Kitchen Pollutants Control And Ventilation: A Ventilation Guide To Asian & European Kitchen Environment 9811364958, 9789811364952, 9789811364969

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Angui Li · Risto Kosonen

Kitchen Pollutants Control and Ventilation A Ventilation Guide to Asian & European Kitchen Environment

Kitchen Pollutants Control and Ventilation

Angui Li Risto Kosonen •

Kitchen Pollutants Control and Ventilation A Ventilation Guide to Asian & European Kitchen Environment

123

Angui Li Xi’an University of Architecture and Technology Xi’an, Shaanxi, China

Risto Kosonen Aalto University Espoo, Finland

ISBN 978-981-13-6495-2 ISBN 978-981-13-6496-9 https://doi.org/10.1007/978-981-13-6496-9

(eBook)

Library of Congress Control Number: 2019930973 © Springer Nature Singapore Pte Ltd. 2019 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Foreword I

Kitchen environment is quite different from the environment of other public and private spaces. Cooking has been recognized as a major source of indoor pollutants, which can cause great harm to people’s health. Furthermore, the large amount of heat and moisture generated during cooking process by closely located sources increases the risk of extremely uncomfortable thermal and olfactory environment for employees which is often ignored. Kitchen pollution (heat and contaminants) generation and ventilation theory need to be well understood for maintaining good environment as well as for reducing energy consumption. Because the kitchen environment is so specific and important, professors Angui Li and Risto Kosonen jointly wrote this book. Angui Li and Risto Kosonen are top-level scientists with great expertise in the field of ventilation obtained over 30 years of research and practical implementation of engineering solutions. In this book Kitchen Pollutants Control and Ventilation, they summarize the accumulated knowledge and achievement over the years in the field of kitchen ventilation. This book introduces the pollutants generated during cooking and the kitchen ventilation principles in a comprehensive way. The book is a practical and easily understandable guide for design, operation, and evaluation of Asian and European kitchen systems and environment. It covers the fundamentals as well as the most advanced topics of kitchen ventilation. The recent developments in kitchen ventilation research and its applications in practice are presented. The book, written for HVAC researchers, designers, engineers, and other professionals, will instruct readers on how to apply effectively ventilation to remove generated pollution and to ensure a good air quality in kitchens. This book provides basis for the development of standards. Lyngby, Denmark July 2018

Arsen Melikov Technical University of Denmark

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Foreword II

Kitchen ventilation and pollution control is a complex combination of processes and technologies which requires an in-depth understanding of numerous cooking processes, climatic conditions, building construction methods, thermodynamics, fluid mechanics, biology, and chemistry. Modern kitchens especially commercial and industrial production kitchens are multifaceted indoors spaces contained within various types of buildings, which are required to be ventilated effectively in order to make them safe and comfortable for human beings who have to work in these spaces for long hours on daily basis. Heat and pollutants generated in these kitchens by cooking processes, combustion of fuels, and generation of biological hazards are complicated and are diverse according to the cultural, ethnic, culinary, and regional customs around the globe. This diversity has always been a challenge for the professional kitchen designers and HVAC engineers to design and select an effective and energy-efficient ventilation system for their projects. I, personally being a food service design consultant in professional practice for over 38 years, have always found it a challenge. This has largely been due to the lack of authoritative and well-researched reference material available to industry professionals as an authoritative guide to kitchen ventilation prerequisites and principles. The only reference material available until now has been the ASHRAE guide which is rather generic in nature and has left several parameters to open-ended suppositions. I am deeply impressed by the meticulous research work and dedication of Prof. Angui Li and Prof. Risto Kosonen for writing this monumental compendium and guide book which shall serve us well as a design guide book for many years to come. It is an invaluable resource for industry professionals as well as for students of engineering who wish to become HVAC engineers or kitchen planners.

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Foreword II

In the end, I wish to congratulate the authors, Prof. Angui Li and Prof. Risto Kosonen, for writing this greatly needed book, which I for sure will be using as an authoritative reference for all my future design projects. On that note, happy reading to all who seek knowledge to excel. Kuala Lumpur, Malaysia August 2018

Ahmed Subactog FCSI

Foreword III

The indoor air comfort within hot prep kitchen environments has always been a cause for great concern for industry professionals entrusted with addressing such problems as well as for hospitality operators and end users over several decades now. Culinary personnel are exposed to toxic burnt gases, heat stress, noise, in an increasingly hazardous work environment. Good ventilation engineering goes a long way in creating a comfortable indoor air climate that helps promote work productivity, personal health and well-being, work creativity, and a better management of work-related stress. Cooking has been recognized as a major source of indoor and outdoor pollutants, capable of causing great harm to people’s health. The heat source in kitchens especially due to burn gases is somewhat concentrated, resulting in large amount of heat and moisture emitted during the cooking process. The risks related to employee well-being in such hazardous environments have been very often overlooked due to weak legislation and poor in-depth understanding of the subject by the relevant professionals who could have made a real difference to ventilation engineering. Even now this is a very poorly understood field of science, and this book is therefore timely not only for industry professionals but also for people who manage local codes of practice. Hence, it is applaudable that we now obtain a comprehensive, well-researched work of scholarship from Professors Angui Li and Risto Kosonen on kitchen pollutants and ventilation theory, which I believe can help shed light on the required methodologies to ensuring good kitchen air quality as well as reducing energy consumption in line with current sustainability measures. I have known Risto Kosonen for several years now and have often engaged with him in work-related situations to discuss the prevalent problems in the HVAC field. Angui Li and Risto Kosonen are primary experts in the field of ventilation, have carried out extensive research over 30 years of industry engagements, and have a unique view in this field of ventilation. Kitchen pollutants control and ventilation is the final product of their long years of professional endeavor.

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Foreword III

This is an excellent book that covers the fundamentals as well as the advanced topics of kitchen ventilation and presents the most recent development in research and its corresponding applications. Written for HVAC researchers, designers, engineers, etc., this book will be useful for industry professionals in food service and ventilation engineering on how to effectively apply the right principles to ensure good indoor air quality in kitchens. Having gone through the full span of this book and its contents, I recommend it highly as a great source of reference for professionals engaged in this field of work. Kuala Lumpur, Malaysia August 2018

Alburn S. William President, CKP Hospitality Consultants

Preface

This book is authored by Angui Li (Xi’an University of Architecture and Technology, China) and Risto Kosonen (Aalto University, Finland), It is written based on the vast experience of the authors in the field of both Asian and European kitchen ventilation, includes their knowledge of the subject, and presents the results mainly from extensive research programs, some of which were supported by the National Science Foundation of China (NSFC) and Finnish Funding Agency for Technology and Innovation (TEKES). Kitchens of residential and commercial buildings play an important role in life, whereas also they are the main source from which contaminants are generated, due to the cooking process. These contaminants significantly affect indoor air quality and have a serious impact on people’s health. Properly designed kitchen ventilation systems are essential for the removal of pollutants and maintain good indoor air quality. To achieve the aims, combined with the characteristics of Asia and European catering industry, the authors analyze and discuss pollutants control and ventilation in kitchens, especially for multi-storey and high-rise buildings in China and Europe. The distribution characteristics of oil fume and thermal plume under typical cooking mode are found out. The theoretical basis and method for calculating the exhaust airflow rate of exhaust shaft are put forward, and the design method of high-performance ventilation for kitchen is given. This book covers kitchen pollutants control, the theoretical basis of high-performance ventilation and advanced technologies and design methods. The emphasis of the book has been laid on the theoretical research and engineering practice; it is suitable for HVAC researchers, engineers, kitchen designers, and related fields, such as research, system design, and operation management. It can also provide reference for environmental management and industry law enforcement. The book is divided into nine chapters. Chapters 1–3 contain an introductory chapter in which the cooking history and development of kitchen techniques, requirements for kitchen ventilation are expounded and then proceeds to and physical, chemical and microbial pollutions of cooking oil fume and their health risks. Next four chapters are concerned with design solutions on airflow rate, energy xi

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Preface

saving potential, and high-performance kitchen ventilation. The last two chapters are devoted to stack effects of kitchen exhaust shaft in high-rise buildings. Typical case studies have been chosen, focused on ventilation design for a high-rise residential building and commercial kitchens, to give a well understandability of kitchen ventilation. Chapters 1–3, 5, and 7–9 of the book are mainly completed by Angui Li, and Chaps. 4–6 are mainly completed by Risto Kosonen. Finally, Prof. Angui Li is indebted to National Science Foundation of China (NSFC) of the financial support (Nos. 51178374 and 50778145). Meanwhile, Prof. Risto Kosonen wants to thank Finnish Funding Agency for Technology and Innovation (TEKES) of the financial support. We also thank Dr YJ Zhao, Dr ZJ Liu, DH Jiang, JH Zhou and MX Gao for their contribution in this study; Ms O Han and HM Huo help to prepare the manuscript, and Derek Schrock did careful revisions of the manuscript. Thanks to Arsen Melikov, Ahmed Subactog, and Alburn S. William for reviewing the book and writing forewords. Xi’an, China Espoo, Finland June 2018

Angui Li Risto Kosonen

Contents

1 Cooking History and Development of Kitchen Appliances 1.1 Development of Cooking Process in Human History . 1.2 Chinese Cooking Techniques . . . . . . . . . . . . . . . . . . 1.2.1 Culinary Traditions of Chinese Cuisine . . . . . 1.2.2 Typical Chinese Cooking Techniques . . . . . . 1.3 European Cooking Techniques . . . . . . . . . . . . . . . . . 1.3.1 European Cuisine . . . . . . . . . . . . . . . . . . . . . 1.3.2 Typical European Cooking Techniques . . . . . 1.4 Kitchen History and Development . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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2 Kitchen Ventilation Requirements . . . . . . . . . . . . . . . . . 2.1 Pollutants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Natural Ventilation Principle . . . . . . . . . . . . . . . . . . 2.2.1 Flow Characteristics of Openings . . . . . . . . 2.2.2 Wind-Driven Ventilation . . . . . . . . . . . . . . . 2.2.3 Buoyancy-Driven Ventilation . . . . . . . . . . . 2.2.4 Hybrid Ventilation . . . . . . . . . . . . . . . . . . . 2.3 Mechanical Ventilation Principle . . . . . . . . . . . . . . . 2.4 Evaluation of Kitchen Indoor Air Quality . . . . . . . . . 2.4.1 Evaluation Indexes . . . . . . . . . . . . . . . . . . . 2.4.2 Improvement of Kitchen Indoor Air Quality References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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3 Pollutions of Cooking Oil Fume and Health Risks 3.1 Measurmental and Analytical Methodology . . 3.1.1 Measurement Points’ Layout . . . . . . . 3.1.2 PM10 /PM2:5 . . . . . . . . . . . . . . . . . . . 3.1.3 VOCs . . . . . . . . . . . . . . . . . . . . . . .

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3.1.4 Total Number of Bacteria . . . . . . . . . . . . . . . . . . . . 3.1.5 Others . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Real-Time online Monitoring System of Cooking Fume . . . . 3.3 Physical Properties of Cooking Pollutants . . . . . . . . . . . . . . 3.3.1 Particle Mass Concentration from Cooking . . . . . . . 3.3.2 Particle Sizes of Pollutants from Cooking . . . . . . . . 3.4 Chemical Properties of Cooking Pollutants . . . . . . . . . . . . . . 3.4.1 CO/CO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.2 VOCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.3 N-Alkanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.4 PAHs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.5 Aldehydes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.6 Fatty Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.7 Dicarboxylic Acids . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.8 Molecular Biomarkers . . . . . . . . . . . . . . . . . . . . . . 3.4.9 Others . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 Microbial Contamination in Kitchen . . . . . . . . . . . . . . . . . . 3.5.1 Air Microbial Contamination Status of Kitchens . . . 3.5.2 Measures for Preventing Cross-contamination . . . . . 3.6 Health Risks of Particulate Matter on Children’s Upper Respiratory Tracts (URTs) . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6.1 Velocity Pattern in Oropharyngeal Region Under Sedentary Condition . . . . . . . . . . . . . . . . . . . . . . . . 3.6.2 Flow Characteristics of Pediatric Upper Respiratory Tract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6.3 Effect of Particle Size on Deposition Rate . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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4 Thermal Environment in Kitchen . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Thermal Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.1 Heat Exchange Between Human Body and Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.2 The Human Body Physiological Response of Thermal Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Thermal Comfort and Thermal Sensation . . . . . . . . . . . . . . . . 4.2.1 The Whole Body Thermal Sensation . . . . . . . . . . . . . 4.2.2 Local Thermal Comfort . . . . . . . . . . . . . . . . . . . . . . 4.2.3 Adaptable Thermal Comfort . . . . . . . . . . . . . . . . . . . 4.2.4 Productivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Classification of Thermal Environment . . . . . . . . . . . . . . . . . . 4.4 Evaluation of Thermal Environment . . . . . . . . . . . . . . . . . . . . 4.4.1 Equipment for Thermal Comfort Measurement . . . . . . 4.4.2 Field Measurement . . . . . . . . . . . . . . . . . . . . . . . . . .

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4.5 Case Study of Western-Style Commercial Kitchen . . . . . . . . . . . 182 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 5 Basis to Calculate Exhaust Airflow Rate . . . . . . . . . . . . . . . . . . . 5.1 Investigation of Thermal Plumes of Kitchen Appliances . . . . 5.1.1 Theory of Thermal Plumes . . . . . . . . . . . . . . . . . . . 5.1.2 Physical Experiments of Kitchen Appliances Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.3 Thermal Plumes of Kitchen Appliances During Idle Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.4 Thermal Plumes of Kitchen Appliances During Cooking Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.5 Comparison of Thermal Plumes During Idle and Cooking Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Methods to Set Airflow Rates . . . . . . . . . . . . . . . . . . . . . . . 5.2.1 Engineering Experience . . . . . . . . . . . . . . . . . . . . . 5.2.2 Load-Based Design . . . . . . . . . . . . . . . . . . . . . . . . 5.2.3 Face Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2.4 Exhaust Hood Area Method Used in China . . . . . . . 5.2.5 Room Energy Balance Method . . . . . . . . . . . . . . . . 5.2.6 Convection Load-Based Design . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Design of Kitchen Ventilation . . . . . . . . . . . . . . . . . . . . 6.1 Guaranteed Operation Preconditions . . . . . . . . . . . . 6.2 Operation Preconditions of Kitchen Ventilation . . . 6.3 The Meaning of Design Solutions on Airflow Rate and Energy Saving Potential . . . . . . . . . . . . . . . . . 6.4 Energy Saving Potential . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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7 High-Performance Kitchen Ventilation . . . . . . . . . . . . . . . . . . . . 7.1 Influence Factors on the Ventilation Efficiency of Kitchen . . 7.1.1 Kitchen Hoods and Exhaust Fans . . . . . . . . . . . . . . 7.1.2 Grease Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1.3 Ventilated Ceiling Ventilation in Kitchen . . . . . . . . 7.1.4 Architectural Parameters of Kitchen . . . . . . . . . . . . 7.2 Method to Determine Capture and Containment Performance of Kitchen Hoods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.1 Determining Threshold of Capture and Containment (ASTM F1704 2012) . . . . . . . . . . . . . . . . . . . . . . . 7.2.2 Determining Heat Load to Space . . . . . . . . . . . . . . . 7.2.3 Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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7.3

Determining the Capture Efficiency . . . . . . . . . . . . . . . . . . . . 7.3.1 Sarnosky’s Derivation . . . . . . . . . . . . . . . . . . . . . . . 7.3.2 A Modified Derivation for Capture Efficiency . . . . . . 7.3.3 Determining of Capture Efficiency for Residential Kitchen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Effect of Relevant Parameters on Hood Performance . . . . . . . 7.4.1 Effect of Range Top Diversity on Capture and Containment Performance . . . . . . . . . . . . . . . . . . . . . 7.4.2 Diversity in Hood Shapes . . . . . . . . . . . . . . . . . . . . . 7.4.3 Diversity on Rear Seal and Side Panels . . . . . . . . . . . 7.5 The Performance of Typical Chinese-Style Cooking Hoods . . . 7.6 Effects of Appliance Diversity and Position on Commercial Kitchen Hood Performance (Capture and Containment Exhaust Airflow Rate) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6.1 Airflow Requirements for like-Duty Appliance Lines . 7.6.2 Diversity in Appliance Usage . . . . . . . . . . . . . . . . . . 7.6.3 Diversity in Appliance Duty and Position . . . . . . . . . 7.7 Residential Exhaust Systems Performance . . . . . . . . . . . . . . . 7.8 Effects of Mannequin and Walk-by Motion on Hood Spillage . 7.9 Design Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10 Performance Analysis of Enhanced Ventilation Systems for Kitchen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10.1 Low Radiation Cooking Equipment for Commercial Kitchen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10.2 Ventilated Ceiling System Capture and Containment Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10.3 Push-Pull Ventilation System in Residential Kitchen . 7.11 CFD Simulation of Kitchen Ventilation . . . . . . . . . . . . . . . . . 7.11.1 Indoor Air Quality of a Commercial Kitchen in China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.11.2 Indoor Air Quality Inside a Community Kitchen . . . . 7.11.3 Effect of the Shape of Separation Plate on Kitchen Hood Performance . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8 Stack Effects of Kitchen Exhaust Shaft in High-Rise Buildings . 8.1 Main Types of Kitchen-Centralized Exhaust System . . . . . . . 8.2 Theoretical Calculation of Centralized Exhaust Shaft . . . . . . 8.2.1 Flow Resistance Loss . . . . . . . . . . . . . . . . . . . . . . . 8.2.2 Local Resistance Loss at the Combining T Junctions (Combining Ts) . . . . . . . . . . . . . . . . . . . . . . . . . . .

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8.3

Drag Reduction Measures . . . . . . . . . . . . . . . . . . . 8.3.1 Turning Vane/Deflector . . . . . . . . . . . . . . 8.3.2 Change the Flow Channel Form . . . . . . . . 8.4 Pressure Loss of the Local Components . . . . . . . . . 8.5 Influence Factors of Exhaust Effect of Shaft . . . . . . 8.5.1 Shapes and Structures of Shaft . . . . . . . . . 8.5.2 Cross-sectional Size of Shaft . . . . . . . . . . . 8.5.3 Non-constant Cross-sectional Shaft . . . . . . 8.6 Kitchen Exhaust Hoods Performance . . . . . . . . . . . 8.7 Operating Rate and Location of Kitchen Hoods . . . 8.8 Effect of Temperature Difference on Exhaust Shaft . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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9 Case Study and Design of Kitchen Ventilation . . . . . . . . . . . . . 9.1 Design Calculation of Residential Centralized Exhaust System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2 Ventilation Design for a High-Rise Residential Building . . . 9.2.1 Design Procedures . . . . . . . . . . . . . . . . . . . . . . . . 9.2.2 Selection of Centralized Exhaust Shaft . . . . . . . . . 9.2.3 Design Parameters . . . . . . . . . . . . . . . . . . . . . . . . 9.2.4 Cross-Sectional Size Check of Centralized Exhaust Shaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.3 Ventilation Design for a Commercial Kitchen A in China . . 9.3.1 Exhaust Airflow Rate . . . . . . . . . . . . . . . . . . . . . . 9.3.2 Makeup Airflow Rate . . . . . . . . . . . . . . . . . . . . . . 9.3.3 Calculation Principle of Ventilation Duct and Vent Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.3.4 Pressure Loss for Duct and Fan Selection . . . . . . . 9.4 Ventilation Design for a Commercial Kitchen B in China . . 9.4.1 Ventilation Categories in Kitchen . . . . . . . . . . . . . 9.4.2 Exhaust Airflow Rate . . . . . . . . . . . . . . . . . . . . . . 9.4.3 General Ventilation Airflow Rate . . . . . . . . . . . . . 9.4.4 Makeup Airflow Rate . . . . . . . . . . . . . . . . . . . . . . 9.4.5 Pressure Loss for Duct and Fan Selection . . . . . . . 9.5 Ventilation Design for an Institutional School Kitchen in Europe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.6 Ventilation Design for a Restaurant Kitchen in Europe . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

347 348 348 349 353 353 354 357 358 362 367 373

. . . . 375 . . . . .

. . . . .

. . . . .

. . . . .

375 379 379 380 382

. . . .

. . . .

. . . .

. . . .

385 385 385 389

. . . . . . . .

. . . . . . . .

. . . . . . . .

. . . . . . . .

389 391 393 393 395 397 397 397

. . . . 401 . . . . 404 . . . . 407

Nomenclature

a A b c cp C Cd Ch Cp Cs Dh f fcl g h hc hr hk Dh H Icl Iu kc kr ks kw Ka l m Ma

Velocity distribution factor (–) Area (m2) Temperature distribution factor (–) Concentration (kg/m3) Specific heat (J/(kg
K)) Rate of heat exchange by convection (W/m2) Discharge coefficient for an opening (–) Perimeter of exhaust hood (m) Surface pressure coefficient (–) Shaft section perimeter (m) Equivalent diameter (m) Product-specific factor of the virtual origin (–) Clothing surface area factor (–) Acceleration due to gravity (m/s2) Vertical distance (m) Convective heat transfer coefficient (W/(m2
K)) Radiative heat transfer coefficient (–) Heat transfer coefficient of the shaft wall (W/m2
°C) Specific enthalpy (kJ/kg) Enthalpy flux (W) Clothing insulation (m2
K/W) Local turbulence intensity (%) Cowl pressure coefficient (–) Reduction factor of installation place (–) Spillage coefficient (–) Window leakage factor (–) Absolute surface roughness (mm) Length (m) Mass (kg) Molecular mass (g/mol)

xix

xx

n N P DPfric Pj qg qv r Rt Rv SC SE SP ta to tmr trm tpr ∆t ∆te ∆tpr T V vh vc w z z0 a b bq d dv dt di η ηc hage j k n q rj s C

Nomenclature

Number (–) Air change rate (1/h) Pressure (kPa) Friction loss (Pa) Connected load of the kitchen equipment j (–) General ventilation rate (m3/h) Exhaust airflow rate (m3/h) Width of plume (m) Width of the temperature profiles (m) Width of the velocity profile (m) Contaminant captured by the hood (kg/s) Contaminant escaping from the hood (kg/s) Contaminant produced at the source (kg/s) Air temperature (°C) Operative temperature (°C) Mean radiant temperature (°C) Running mean outdoor temperature (°C) Plane radiant temperature (°C) Temperature differences (°C) Excess temperature (°C) Radiant asymmetry (°C) Absolute temperature (K) Volume (m3) Capture velocity at the exhaust hood entrance (m/s) Axial velocity (m/s) Width (m) Height above cooking surface (m) Virtual origin (m) Entrainment factor (–) Angle of central shaft and branch flue (°) Exhaust unbalance coefficient (–) Spreading angle of cooking thermal plume (°) Spreading angle of velocity profiles (°) Spreading angle of temperature profiles (°) Thickness of shaft wall (mm) Operating rate (%) Capture efficiency (–) Age of air (s) Thermal expansion coefficient (–) Friction coefficient (–) Pressure loss coefficient (–) Density (kg/m3) Room load factor of the hood for the equipment j (–) Time (s) Momentum flux (kg/m
s2)

Nomenclature

u Uconv Ufume v wj X

xxi

Simultaneous factor of kitchen equipment (–) Convective heat output of the cooking appliance (W) Heat capacity of the cooking exhaust fume (kg/h) Ratio factor of temperature and velocity distribution (–) Sensible heat proportion of the connected load of the equipment j (W/W) Kinetic energy flux (W)

Chapter 1

Cooking History and Development of Kitchen Appliances

Abstract Kitchen environment is quite different from the environment of other public and private spaces. Kitchen ventilation is a complex combination of processes and technologies which requires an in-depth understanding of numerous cooking processes, climatic conditions, building construction methods, thermodynamics, and fluid mechanics. This chapter covers the history of cooking as well as the most recent development in research and its corresponding applications in Asia and Europe.

1.1 Development of Cooking Process in Human History Generally, cooking or cookery is the art, technology, and craft of preparing food for consumption with the use of heat. Cooking techniques and ingredients vary widely all over the world, from grilling food over an open fire to using stoves, to baking in various types of ovens, reflecting unique environmental, economic, and cultural traditions and trends. Preparing food with heat or fire is an activity unique to humans, which terminated the era almost entirely using raw ingredients. In South Africa, phylogenetic analysis suggests that human ancestors may have invented cooking as far back as 1.8–2.3 million years ago (Organ et al. 2011). Evidence for the controlled use of fire by Homo erectus beginning at 400,000 years ago is scholarly supported (Berna et al. 2012; Miller 2013). Archaeological evidences, from 300,000 years (Smith 2014) in the form of ancient hearths, earth ovens, burnt animal bones, and flint, are found across Europe and the Middle East. Archaeologists have discovered burnt bone fragments and plant ashes from the Wonderwerk Cave, which has provided evidence supporting human control of fire (see Fig. 1.1). Most anthropologists believe that widespread cooking fires began only about 250,000 years ago, when hearths came into being (Pennisi 1999). In Asia, the evidence of controlled use of fire during the Lower Paleolithic is found in Xihoudu in Shanxi Province, China. The black, gray, and grayish-green discoloration of mammalian bones was found at the site illustrating the evidence of burning by early hominids (Jia 1978; James 1989). Another early site is Yuanmou, near Shangnabang, Yunnan Province, where two Homo erectus incisors were found in 1965. Later excavations uncovered several stone tools and non-hominid vertebrate © Springer Nature Singapore Pte Ltd. 2019 A. Li and R. Kosonen, Kitchen Pollutants Control and Ventilation, https://doi.org/10.1007/978-981-13-6496-9_1

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1 Cooking History and Development of Kitchen Appliances

Fig. 1.1 An archaeological site inside Wonderwerk Cave in South Africa (1 million year ago)

fossils that are suggestive of burning, which date back to 1.7 million years BP (BP stands for before the present which accustomed to regard 1950 as the starting point) (Yi 1980; Olsen and Wu 1985). Evidences at Zhoukoudian cave (see Fig. 1.2) in China date back control of fire as early as 230,000–460,000 BP (Huang 1995; Nicholson 1998). Fire in Zhoukoudian is suggested by the presence of burned bones, burned chipped-stone artifacts, charcoal, ash, and hearths. This evidence comes from Zhoukoudian, also known as the Peking Man Site, where several bones were found to be uniformly black to gray. The extracts from the bones were determined to be characteristic of burned bone rather than manganese staining. The site itself does not show that fires were made in Zhoukoudian, but the association of blackened bones with quartzite artifacts at least shows that humans did control fire at the time of the habitation of the Zhoukoudian cave (Yi 1980; Weiner et al. 1998; Gao et al. 2016). Utilization of natural resources has been developed widely by intelligent people in recent years. When people found hot stones can also play a role in cooking food, stone cooking method has appeared. The stone bread, which is traced to prehistoric flavored food in Shaanxi Province, northern China, is a widespread product of the stone cooking method. The expansion of agriculture, commerce, trade, and transportation between civilizations in different regions offered many new ingredients for cooking technology. Both baking and “hot stone” are no longer suitable for cooking grain when time goes to agrarian age which people grow grain on a big scale. People inevitably need a new cooking way to make grain really delicious when grain gradually becomes the staple food of human. New inventions and techniques, such as the invention of pottery for holding and boiling water (see Fig. 1.3), expanded cooking technologies a lot. The remains of burnt pits in Neolithic and Paleolithic Ages, coarse, and crude “chimneys” for natural ventilation are still in evidence, as well as the daily utensils and art works once employed by the people of Banpo, Xi’an city (Li and Jones 2000).

1.1 Development of Cooking Process in Human History

(a)

3

(b)

Fig. 1.2 Zhoukoudian caves, a World Heritage Site and an early site of human use of fire in China (230,000–460,000 years ago). a Looking north, b looking into the site. Reprinted from Reference Goldberg et al. (2001), Copyright 2001, with permission from Elsevier

(a)

(b)

Fig. 1.3 Banpo primitive residential village and invention of pottery. a Banpo primitive residential village in Xi’an, Shaanxi, China: the covered hall, b human faced fish decoration bowl, 5,600~6,700 years ago, Banpo village

The cooking places and cooking methods reflect the rich history, science, and culture, and are the crystallization of the wisdom of the ancient laboring people. In the Shanzhou area of Henan Province, China, in order to prevent wind and earthquake, the local ancestors dig the ground as a hole to built their houses, which are now called “pit courtyards” and have a history of approximately 4,000 years. So far, there are still hundreds of solid and durable sunken courtyards. In the underground pit courtyards, there is a magical stove made of clay—“Chuanshan stove” (Fig. 1.4). The burners are sloping upward in turn, and the chamber of which is connected so that the thermal air flows upward to cook. There are nine burners in turn, and nine pots can be placed. It is very efficient to cook food using these nine burners at the same time. This is why it is always used to cook local specialties “ten bowls of dishes”, which are designed to entertain guests at the dinner of wedding or funeral. The Chuanshan stove makes full use of heat energy. The first burner has the strongest firepower and is suitable for

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1 Cooking History and Development of Kitchen Appliances

(a)

(b)

Fig. 1.4 Chuanshan stove. a Chuanshan stove in the Pit courtyards of Henan Province, China that have a history of approximately 4,000 years, b feasting guests in the Pit courtyards

steaming and boiling. With the gradual decrease of firepower, it has the functions of deep-frying, frying, stewing, simmering, and heat preservation in turn. Although the appearance of the Chuanshan stove is simple, its structure is ingenious, its function is powerful, and it is full of the wisdom of the people living in the underground pit courtyards. In the long stream of history, the discovery of fire, the conscious control of the fire, the development of cooking utensils, and the improvement of cooking methods reflect the continuous progress of cooking technology and the level of the development of social productivity. With technical advance of the human being, the kitchen came into being. The evolution of the kitchen is linked to the invention of the cooking range or stove and food. Technical advances in heating food in the eighteenth and nineteenth centuries changed the architecture of the kitchen. A kitchen is a room or part of a room used for cooking and food preparation in a dwelling or in a commercial establishment. The main function of a kitchen is serving as a location for storing, preparing food, and cooking or doing related tasks.

1.2 Chinese Cooking Techniques 1.2.1 Culinary Traditions of Chinese Cuisine Pollutants in kitchens have a close connection with the cooking techniques. In China, unique regional cuisines evolved and gained widespread acceptance, because of China’s varying climate, enormous size, and topography. Basically, Chinese cuisines

1.2 Chinese Cooking Techniques

5

Fig. 1.5 Eight Culinary Traditions of Chinese cuisine

have many schools in cooking based on the different ethnic cultures and geographical environments. Some of the most influential and representative classifications recognized by the community are Shandong, Sichuan, Cantonese, Fujian, Jiangsu, Zhejiang, Hunan, and Anhui, which are often called as the Eight Culinary Traditions of Chinese cuisine (see Fig. 1.5 and Table 1.1). Without doubt, many other local cuisines are famous too, such as Shanghai Cuisine and Beijing Cuisine. The formation of a cuisine has a relative relationship with its long history as well as unique cooking characteristics. The Chinese cuisine today is usually derived from the Eight Culinary Traditions of Chinese cuisine. At the same time, it is also affected by the region’s natural geography, climate conditions, resources and specialty, eating habits, and so on.

1.2.2 Typical Chinese Cooking Techniques The Chinese cooking techniques inherit from the profound and vigorous Chinese traditional culture, which is the harmonious unification of intelligence and operation. It is well known that Chinese cooking techniques are a set of methods and techniques traditionally used in Chinese cuisine. There are usually 24 cooking techniques in Chinese cooking, which can either be grouped into ones that use a single cooking method or a combination of several cooking methods. With 24 common cooking techniques, every cuisine can be cooked into 200–300 dishes (Nakayama 1992). The most typical cooking techniques in Chinese cuisine are stir-frying, deepfrying, steaming, and boiling. During cooking process, a wide range of seasoning is applied and oils are usually first heated at high temperatures in a wok (large metal pans with raised sides). The pollutants emissions are closely related to cooking

Typical dishes

Fried carp with sweet and sour sauce

Kung pao chicken

Stir-fried rice noodles with beef

Cuisines

Shandong cuisine

Sichuan cuisine

Cantonese cuisine

Pictures

Table 1.1 Brief description of Eight Culinary Traditions of Chinese cuisine

(continued)

Cantonese cuisine comes from Guangdong Province and is one of the Eight Culinary Traditions of Chinese cuisines. Its prominence outside China is due to the large number of emigrants from Guangdong (Solomon 1976). Guangzhou, the capital of Guangdong Province, has long been a trading port and many imported foods and ingredients are used in Cantonese cuisine

Sichuan cuisine is a style of Chinese cuisine originating from the Sichuan Province of southwestern China, famed for bold flavors, particularly the pungency and spiciness resulting from liberal use of garlic and chili peppers, as well as the unique flavor of the Sichuan peppercorn, Chinese red pepper and facing heaven pepper. Peanuts, sesame paste, and ginger are also prominent ingredients in this style (Dunlop 2003)

Shandong cuisine (also called Lu cuisine) has a long history. It was once an important part of the imperial cuisine and was widely spread in North China. Lu cuisine dishes are known for their fresh, salty, crisp, and tender features. Besides, due to the Jiaodong peninsula is seated in the Bohai and the Yellow sea, Shandong cuisine is characterized by various cooking techniques and seafood ingredients. The typical dishes are braised abalone, braised trepang, sweet and sour carp, and Dezhou chicken

Descriptions

6 1 Cooking History and Development of Kitchen Appliances

Typical dishes

Buddha jumps over the wall

Sweet and sour spareribs

Soysauced Dongpo pork

Cuisines

Fujian cuisine

Jiangsu cuisine

Zhejiang cuisine

Table 1.1 (continued)

Pictures

(continued)

Zhejiang cuisine derives from the traditional ways of cooking in Zhejiang Province in China, south of Shanghai and around the former Chinese capital of Hangzhou. In general, Zhejiang-style food is not greasy but has a fresh and soft flavor with a mellow fragrance. Zhejiang cuisine consists of at least three styles, namely Hangzhou, Shaoxing, and Ningbo subcuisines. Some sources also include the Wenzhou style as a separate subdivision (due to its proximity to Fujian), characterized as the greatest source of seafood as well as poultry and livestock (Benjamin et al. 1910)

Jiangsu cuisine consists of the styles of Yangzhou, Nanjing, Suzhou, and Zhenjiang dishes. It is especially prevalent in the lower reach of the Yangtze River. Jiangsu cuisine is characterized by soft, but not mushy or falling apart. Typical Jiangsu cuisine includes Jinling salted dried duck, crystal meat, clear crab shell meatballs, Yangzhou steamed jerky strips, triple combo duck, etc

Fujian cuisine is one of the native Chinese cuisines derived from the native cooking style of Fujian Province in China, most notably from the Fuzhou region. Fujian-style cuisine is known to be light but flavorful, soft, and tender, with particular emphasis on umami taste, known in Chinese cooking as “xianwei,” as well as retaining the original flavor of the main ingredients instead of masking them. Many diverse seafoods and woodland delicacies are used and the most commonly employed cooking techniques in the region’s cuisine include braising, stewing, steaming, and boiling. Strong emphasis is put on the making and utilizing of broth and soups (Grigson 1985)

Descriptions

1.2 Chinese Cooking Techniques 7

Typical dishes

Steamed fish head with chili pepper

Soy braised mandarin fish

Cuisines

Hunan cuisine

Anhui cuisine

Table 1.1 (continued)

Pictures

Anhui cuisine is derived from the native cooking styles of the Huangshan mountains region in China and is similar to Jiangsu cuisine. Anhui cuisine is known for its use of wild herbs, from both the land and the sea, and simple methods of preparation. Braising and stewing are common cooking techniques. Anhui cuisine can be classified as the Yangtze River region, Huai River region, and southern Anhui region. Because Anhui Province has ample uncultivated fields and forests, the wild herbs used in the region’s cuisine are readily available

Hunan cuisine, also known as Xiang cuisine, consists of the cuisines of the Xiang River region, Dongting Lake, and western Hunan Province in China. It is famous for its hot spicy flavor, fresh aroma, and deep color. Frequently used cooking techniques include stewing, frying, pot-roasting, braising, and smoking. There are a variety of ingredients in Hunan dishes, such as chili peppers, shallots, and garlic. Hunan cuisine is known for being dry hot or purely hot and uses smoked and cured goods in its dishes much more frequently; this is a significant difference with the Sichuan cuisine

Descriptions

8 1 Cooking History and Development of Kitchen Appliances

1.2 Chinese Cooking Techniques

9

techniques. The processes used in cooking such as frying, roasting, grilling, boiling, and broiling contribute to pollutant emissions and are affected by ingredients, recipes and procedures, fuel types, temperature, and extraction/ventilation equipment (Zhang et al. 2013). The emissions include grease particles, vapor and smoke, products of heat, combustion, and moisture. (1) Stir-Frying Stir-frying is a Chinese cooking technique in which ingredients are fried in a small amount of very hot oil while being stirred in a wok (see Fig. 1.6). This technique originated in China, and in recent centuries has spread into other parts of Asia and the West. Many claimed that this quick, hot cooking seals in the flavors of the foods, as well as preserving their color and texture (Liley and Vicki 2007). Scholars think that wok (or pan) frying may have been used as early as the Han dynasty (206 BC–220 AD) for drying grain, not for cooking, but it was not until the Ming dynasty (1368–1644) that the wok reached its modern shape and allowed quick cooking in hot oil (Wilkinson 2012). Well into the twentieth century, while restaurants and affluent families could afford the oil and fuel needed for stir-frying, the most widely used cooking techniques remained boiling and steaming. Stir-fry cooking came to predominate over the course of the century as more people could afford oil and fuel, and in the West spread beyond Chinese communities (Anderson 1988). Stir-frying has been promoted as healthy and nutritious. Cooks extolled the quick cooking at high heat for retaining color, texture, and nutritional value. But, stir-frying is not without health risks. Recent studies show that heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are formed by stir-frying meat at very high temperatures. These chemicals cause DNA changes that may contribute to increased risk of cancer (National Cancer Institute 2015). (2) Deep-Frying Deep-frying food is defined as a process where food is completely submerged in hot oil at temperatures typically between 180 and 190 °C (see Fig. 1.7). One common Fig. 1.6 Typical Chinese cooking technique: stir-frying

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1 Cooking History and Development of Kitchen Appliances

Fig. 1.7 Typical Chinese cooking technique: deep-frying

method for preparing food for deep-frying which involves adding multiple layers of batter around the food, such as cornmeal, flour, or tempura, breadcrumbs, may also be used (Bittman 2013). It also can be divided into dry deep-frying, soft deep-frying, and crisp deep-frying. After the food is submerged in oil, the surface of it begins to dehydrate and it undergoes Maillard reactions which break down sugars and proteins, creating the golden brown exterior of the food. Once the surface is dehydrated, it forms a crust which prevents further oil absorption. The heat conducts throughout the food causing proteins to denature starches to undergo starch gelatinization and dietary fiber to soften. Some studies have found that deep-frying which cooking with oil contributes to the production of more particles than cooking with water (See and Balasubramanian 2006a). The largest amount of particulate matter measured (close to the breathing zone of the cook) was generated during deep-frying (PM2.5 190 µg/m3 ) (See and Balasubramanian 2008). In addition, high-temperature frying was found to lead to production of higher molecular weight PAHs, while low-temperature cooking results in formation of lower molecular weight PAHs (See and Balasubramanian 2006a). Consistent studies revealed that particles generated from cooking were found to be mainly in the ultrafine range (about 90% of total particles), with frying being found to generate more particles than any other cooking method (Wallace et al. 2004). The cooking method used has been identified as one of the influential factors affecting emission of some compounds, with deep-frying found to produce more pollutants and an abundance of higher molecular weight PAHs. Deep-frying generated more PAHs than other cooking methods due to the high temperature during cooking as well as the large amount of oil used for this method of cooking. Chinese cooking, on the other hand, was found to emit higher molecular weight PAHs such as benzo, fluoranthene, indeno, pyrene, and benzoperylene. These trends were attributed to the cooking methods employed in each type of cooking from the amount of food cooked, the amount and type of oil used, to the temperatures reached during cooking, and the cooking time (See and Balasubramanian 2006a).

1.2 Chinese Cooking Techniques

11

The deep-frying in olive and sunflower oils has been found to be less of a detriment to health and in some cases have positive effects on insulin levels (Davis 2015). Oil can be reused a few times after original use after straining out solids (Bittman 2013). However, excessive use of the same oil can cause it to break down and release compounds into the food that may be carcinogenic, affect liver health, or influence the body’s ability to absorb vitamins. (3) Steaming Steaming is a method of cooking using steam. This is often done with a food steamer, a kitchen appliance made specifically to cook food with steam, but food can also be steamed in a wok (see Fig. 1.8). In China’s Yellow River Valley, early steam cookers made of stoneware have been found dating back as far as 5000 BC (Chen 1995). Steaming works are most often done by placing the food into a food steamer, typically a circular container made of metal or bamboo. The steamer usually has a lid that is placed on the top of the container during cooking to allow the steam to cook through the food. Food can be steamed inside a wok, supported over boiling water in the bottom of the wok by a stainless steel frame. In physics, a vapor emitted in steaming is a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapor can be condensed to a liquid by increasing the pressure on it without reducing the temperature (Petrucci et al. 2002). A vapor is different from an aerosol. An aerosol is a suspension of tiny particles of liquid, solid, or both within a gas (Cheng 2014). A vapor may coexist with a liquid. Consequently, the two phases will be in equilibrium, and the gas partial pressure will be equal to the equilibrium vapor pressure of the liquid. Analysis of various cooking methods which included steaming, boiling, stirfrying, pan-frying, and deep-frying was obtained by See and Balasubramanian (2008), which revealed that the lowest amount of particulate matter measured at 20 cm from the cooker was generated during steaming (PM2.5 72 µg/m3 ). In addition, water with a boiling point of 100 °C is much more volatile than corn oil which has a boiling point of 245 °C. Therefore, under the high temperature in enclosed kitchen, water droplets are most likely to exist in the gaseous phase than in the

Fig. 1.8 Typical Chinese cooking technique: steaming

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1 Cooking History and Development of Kitchen Appliances

particulate phase while less volatile oil droplets tend to remain as particles. Steaming also released lower particle counts than boiling as the wok was covered during steaming and thus particles could have been trapped inside. (4) Boiling Boiling is the method of cooking food in boiling water, or other water-based liquids such as milk (see Fig. 1.9). The boiling point of water is typically considered to be 100 °C. Pressure and different composition of ingredient may alter the boiling point of the liquid (IAPWS 2009). Boiling can be done in several ways: The food can be placed into already rapidly boiling water and left to cook, and the food can be simmered after absorbing the heat of heating liquid, or the food can also be placed into the pot, and cold water may be added to the pot, then put the pot on the slow fire to burn. This process may last until the food is satisfactory. The boiling time depends on the variety of ingredient and taste of diners. Foods suitable for boiling include vegetables, starchy foods such as rice, noodles, and potatoes, eggs, meats, sauces, stocks, and soups. Additionally, boiling can be subdivided into instant boiling and slow boiling. The instant boiled mutton in northern region of China is the most common dish involving boiling. Boiling is also often used to remove salt from certain foodstuffs, such as bacon, if a less saline product is required. The findings revealed that cooking with water (steaming and boiling) liberated less harmful submicron-sized particles than cooking with oil (stir-frying, pan-frying, and deep-frying). Nanoparticles accounted for 55% (steaming) and 62% (boiling) of all particles during water-based cooking as compared to 69% during stir-frying to 90% during deep-frying. On the other hand, water-based cooking produced more ultrafine and accumulation mode particles presumably due to the higher humidity in the kitchen. The water vapor generated while boiling water could have condensed on pre-existing nanoparticles to form larger particles in the ultrafine and accumulation mode (See and Balasubramanian 2006a). It was reported the content of organic ions in the smoke produced when using several cooking techniques (See and Balasubramanian 2008). Consistent to the trend observed for other organics, techniques that involve the use of water, such as steaming

Fig. 1.9 Typical Chinese cooking technique: boiling

1.2 Chinese Cooking Techniques

13

and boiling, released lower amounts of organic ions than those which involve the use of hot oils. Nonetheless, for organic ions, deep-frying releases the highest amounts of organic ions. The metal content of the aerosol emitted during cooking was analyzed by See and Balasubramanian (2008) during steaming, boiling, stir-frying, pan-frying, and deep-frying. They found that generally, the higher concentrations were observed in those techniques that used mainly oil, and frequently the highest concentrations were found in the smoke released during deep-frying.

1.3 European Cooking Techniques 1.3.1 European Cuisine European cuisine (or alternatively Western cuisine) refer to the cuisine of Europe and other Western countries, including (depending on the definition) that of Russia, as well as non-indigenous cuisine of Australasia, the Americas, Southern Africa, and Oceania, which derive substantial influence from European settlers in those regions. The cuisines of Western countries are diverse by themselves, although there are common characteristics that distinguish Western-style cooking from cuisines of Asian countries and others. Compared with traditional cooking of Asian countries, for example, meat is more prominent and substantial in serving size. Steak and cutlet in particular are common dishes across the West. Western cuisines also put substantial emphasis on grape wine and on sauces as condiments, seasonings, or accompaniments (in part due to the difficulty of seasonings penetrating the often-larger pieces of meat used in Western-style cooking). Many dairy products are utilized in the cooking process, except in nouvelle cuisine. Cheeses are produced in hundreds of different varieties, and fermented milk products are also available in a wide selection. Wheatflour bread has long been the most common source of starch in this cuisine, along with pasta, dumplings, and pastries, although the potato has become a major starch plant in the diet of Europeans and their diaspora since the European colonization of the Americas. Maize is much less common in most European diets than it is in the Americas; however, cornmeal (polenta) is a major part of the cuisine of Italy and the Balkans. Although flatbreads (especially with toppings such as pizza) and rice are eaten in Europe, they do not constitute an ever-present staple. Salads (cold dishes with uncooked or cooked vegetables with sauce) are an integral part of European cuisine. Historically, European cuisine has been developed in the European royal and noble courts. European nobility was usually arms-bearing and lived in separate manors in the countryside. The knife was the primary eating implement (cutlery) and eating steaks and other foods that require cutting followed. Generally speaking, European cuisine can be classified as Central European cuisines, Eastern European cuisine, Northern European cuisine, Southern European

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1 Cooking History and Development of Kitchen Appliances

cuisines (Mediterranean cuisine), and Western European cuisines. Brief description of European cuisine can be seen in Table 1.2 (Parasecoli et al. 2005; https://en. wikipedia.org).

1.3.2 Typical European Cooking Techniques (1) Roasting (such as roast chicken) Roasting is a cooking method that uses dry heat where hot air envelops the food, cooking it evenly on all sides with temperatures of at least 150 °C from an open flame, oven, or other heat source. Roasting can enhance flavor through caramelization and Maillard browning on the surface of the food. Roasting uses indirect, diffused heat (as in an oven) and is suitable for slower cooking of meat in a larger, whole piece. Meats and most root and bulb vegetables can be roasted. Any piece of meat, especially red meat that has been cooked in this fashion, is called a roast. Meats and vegetables prepared in this way are described as “roasted,” e.g., roasted chicken (see Fig. 1.10) or roasted potatoes. For roasting, the food may be placed on a rack, in a roasting pan, or be rotated on a spit or rotisserie to ensure even application of heat. If a pan is used, the juice can be retained for use in gravy, Yorkshire pudding, etc. During oven roasting, hot air circulates around the meat, cooking all sides evenly. There are several plans for roasting meat: low-temperature cooking (95–160 °C), high-temperature cooking, and a combination of both. Each method can be suitable, depending on the food and the tastes of the people. Traditionally recognized roasting methods consist only of baking and cooking over or near an open fire. Grilling is normally not technically a roast, since a grill is used. Barbecuing and smoking differ from roasting because of the lower temperature and controlled smoke application. Grilling can be considered as a low-fat food preparation, as it allows any fat in the food to drip away. Roasted meat products are favored by consumers because of its unique color, aroma, and taste. However, polycyclic aromatic hydrocarbons (PAHs), heterocyclic amine, and other harmful substances formed during roasting processing are great threat to human health (Feng et al. 2009). (2) Baking Baking is a method of cooking food that uses prolonged dry heat, normally in an oven, but also in hot ashes, or on hot stones. The most common baked item is bread (see Fig. 1.11). Heat is gradually transferred “from the surface of cakes, cookies, and breads to their center. As heat travels through, it transforms batters and doughs into baked goods with a firm dry crust and a softer center.” Baking can be combined with grilling to produce a hybrid barbecue variant by using both methods simultaneously, or one after the other. Baking is related to barbecuing because the concept of the masonry oven is similar to that of a smoke pit. It should be noted that “partially

Dishes

Austrian wiener schnitzel

Russian soup

Fish and chips

Cuisines

Central European cuisine

Eastern European cuisine

Northern European cuisine

Pictures

Table 1.2 Brief description of typical European cuisine

(continued)

Northern European cuisine includes Baltic cuisine, Cuisine of the Isles of the North Atlantic (IONA), and Scandinavian cuisine

Eastern European cuisine encompasses many different cultures, ethnicities, languages, and histories of Eastern Europe. It includes Bulgarian cuisine, Serbian cuisine, Belarusian cuisine, Romanian cuisine, Russian cuisine, and so on. The cuisine of the region is strongly influenced by its climate and still varies, depending on a country. For example, countries of the Sarmatic plain (Belarusian, Russian, and Ukrainian cuisine) show many similarities

The Central European cuisine is the cuisine of Central Europe. It includes Austrian cuisine, German cuisine, Hungarian cuisine, Polish cuisine, and so on. The cuisine within each country in the region is strongly influenced by the local climate. For example, German cuisine, Polish cuisine, Austrian and Czech cuisine show many similarities, yet differ from the highlander cuisine in these countries

Descriptions

1.3 European Cooking Techniques 15

Dishes

Spaghetti

Paprika sausage with potatoes at the Zeughauskeller (Swiss cuisine)

Cuisines

Southern European cuisine

Western European cuisine

Table 1.2 (continued) Pictures

Western European cuisine include Belgian cuisine, Dutch cuisine, French cuisine, Monegasque cuisine, Swiss cuisine, and so on

Southern European cuisine includes Mediterranean cuisine, cuisine of the Balkans, cuisine of the Italian Peninsula, and cuisine of the Iberian Peninsula

Descriptions

16 1 Cooking History and Development of Kitchen Appliances

1.3 European Cooking Techniques

17

Fig. 1.10 Roast chicken prepared on a rotating spit

Fig. 1.11 Baked bread

hydrogenated” fats used to improve the quality and shelf life of baked products tend to produce trans fats (including trans fatty acids), which are harmful to human health. (3) Smoking Smoking is the process of flavoring, browning, cooking, or preserving food by exposing it to smoke from burning or smoldering material, most often wood. Meat and fish are often smoked (see Fig. 1.12). Smoking can be classified as cold smoking, hot smoking, and smoke roasting. The smoking of food directly with wood smoke is

18

1 Cooking History and Development of Kitchen Appliances

Fig. 1.12 Hot-smoked chum salmon

known to contaminate the food with carcinogenic polycyclic aromatic hydrocarbons which may cause intestinal type of gastric adenocarcinoma. In Europe, alder is the traditional smoking wood, but oak is more often used now, and beech to a lesser extent. In North America, hickory, mesquite, oak, pecan, alder, maple, and fruit-tree woods, such as apple, cherry, and plum, are commonly used for smoking. Other biomass besides wood can also be employed, sometimes with the addition of flavoring ingredients. Chinese tea-smoking uses a mixture of uncooked rice, sugar, and tea, heated at the base of a wok.

1.4 Kitchen History and Development Since human have learned to use fire to deal with food, to some extent, the cooking appliances appeared. Meat is burned on hot stones, and water is boiled in natural vessels. Although these are not cooking appliances invented by human beings, the cooking began to appear (Chen 2015). In the Neolithic Age, human began to develop agriculture, and at the same time there was pottery (Chen 2015). The emergence of pottery in the history of cooking had epoch-making significance for the reason that the heat transfer of pottery is rather faster than stone, and it is handy to use. During this time, the pottery cooking utensils mainly included pottery fu, pottery jar, pottery li, pottery tripod, pottery zeng, pottery yan, pottery gui, etc. (see Fig. 1.13) (Wang 2013). The pottery fu which form is roughly similar to today’s casserole. It can be used to cook porridge or boil soup. The pottery jar was used for storing and boiling water. In later times, the pottery tripod and pottery li appeared. The shape of the pottery li is similar to the pottery tripod, but its supporting feet is hollow in order to increase heating area. However, these kinds of pottery appliances only can cook liquid food, such as porridge and soup. As a result, the pottery zeng was invented when people wanted to eat some

1.4 Kitchen History and Development

19

Fig. 1.13 Earthenware cooking appliances in the Neolithic Age (Chen 2002)

different tastes of solid food. The shape of the pottery zeng is approximate like the basin or bowl, which has a number of round holes on the bottom. The function of the hole is similar to grates in the steamer. The pottery zeng is a complex object which has two parts. When it is used to cooking, the lower part can be used to stew food, and the water vapor directly supplied to the upper part to steam the food. The pottery yan is a fixed combination of the pottery zeng and the pottery li, a “grate” must be placed in the pottery yan when you use it. The pottery zeng and yan have more “grate hole” and “pottery cover” than other single utensils so that they can meet the need of steaming and boiling. They indicated that the cooking utensils moved from single function to multi-function, from single use to combined use (Wang 2013). A stove that made of bricks or metal is a kitchen appliance designed for the purpose of cooking food. It is the place where the fuel is burned; it mainly plays the role of controlling the fire and making full use of the fire. At the same time, it is the support of the cooker, in order to put pots, cans, cages, and other utensils for cooking (Chen 1999). The creation of stove can be traced back to human cognition and use of fire. Fire is the root of cooking. It should be said that with the fire, there appeared people’s diet culture. The most primitive stove is pit that dug in the land; people can cook directly in the pit or hang food material on other apparatus for cooking. Until late prehistoric real stoves, pottery stoves had appeared. Prehistoric stoves, usually monocular foci, are mostly connected to cooking utensils and have fire door and smoke vent (see Fig. 1.14a) (Zheng 2011). In today’s Chinese rural areas, the stoves mainly are Huo-tang, kitchen stoves, kitchen stoves with Kang, gas stove, solar cooker, etc.

20

1 Cooking History and Development of Kitchen Appliances

(a)

(c)

(b)

Fig. 1.14 Stoves. a Prehistoric pottery stoves without handle, b prehistoric pottery stoves with handle, c the large-scale fu and stove in the picture of Han dynasties of China (Xu 1999)

(1) Huo-tang Huo-tang (see Fig. 1.15) is the kitchen stove form of traditional gan lan-type common people residence in southern areas of China. Huo-tang is generally set in the middle or the side of the living room on the second floor of the gan lan residence. The Huo-tang usually is a square hole, which is as the concave furnace excavated on the floor. People burn firewood in Huo-tang, above which is a three-legged iron stand for supporting a circular iron pot ring. The Huo-tang not only can meet all the cooking needs of people, but also can dry clothes in winter or rainy season (Wang 2011).

Fig. 1.15 Huo-tang in Yunnan Province of China (Wang 2011)

1.4 Kitchen History and Development

21

Fig. 1.16 Kitchen hearth in Qidong region of Jiangsu Province (Wang et al. 2010)

(2) Kitchen Hearth Agriculture dominates the economy in some areas of China which is rich in combustion resources, so burning method of the traditional farmhouse kitchen still is widely used in this region. For thousands of years, the kitchen hearth was the center of the household. The three-burner kitchen hearth (see Fig. 1.16) is typically used in the farmer’s home. This kitchen hearth is made up of kitchen stove, chimney and bellow, etc., and it use wood or straw as the fuel to cook food. (3) Kitchen Stoves with Kang Chinese Kang is associated with the stoves (see Fig. 1.17), in the traditional rural and the northern district, which called “warm bed”. With the same airflow rate of the equivalent fuel stoves, the Chinese Kang is more energy-efficient and is used widely in Chinese rural and the northern district. The invention of the Chinese Kang extends the function of the stove from the kitchen to the house and enhances the performance of cooking appliances, which is an intelligent design in the development of kitchen ventilation. (4) Gas Stove Gas stove is one of the China modern stoves; it uses manufactured gas or liquefied petroleum gas as a fuel source. The gas stove is composed of a stove body, a bracket, an air inlet bend pipe, a control valve knob, a burner, an air adjusting plate, and other components; it needs to be equipped with gas pipeline or liquefied petroleum gas cylinder, pressure reducing valve, rubber hose, and other accessories. Gas stove is widely used in urban families and restaurants because it is convenient, safe, and hygienic. (5) Solar Cooker A solar cooker (see Fig. 1.18) is a device which uses the energy of direct sunlight to processed food. The solar cooker has been widely used in some Chinese rural

22

1 Cooking History and Development of Kitchen Appliances

Fig. 1.17 Chinese stoves with Kang (Yang 2007)

Fig. 1.18 Boiling water with a solar cooker

areas like Gansu, Qinghai, Tibet, and other remote areas, and China has made some progress in the development of low-cost practical solar cooker. The solar cooker is popular with the people in rural area especially the area which is rich in solar energy and lack of other energy resource because its simple structure, convenient manufacture, and low cost (Liu and Yu 2008). Of the culinary utensils of the ancients, our knowledge is very limited, but as the art of living, in every civilized country, is pretty much the same, the instruments for cooking must, in a great degree, bears a striking resemblance to one another (Beeton 1861). For example, in the Middle Eastern villages and towns of the middle first millennium AD, historical and archaeological sources record that Jewish households generally had stone measuring cups, a meyh.am (a widenecked vessel for heating water), a kederah (an unlidded pot-bellied cooking pot),

1.4 Kitchen History and Development

23

a ilpas (a lidded stewpot/casserole pot type of vessel used for stewing and steaming), yorah and kumkum (pots for heating water), two types of teganon (frying pan) for deep- and shallow-frying, an iskutla (a glass serving platter), a tamh.ui (ceramic serving bowl), a keara (a bowl for bread), and a lagin (a wine decanter),etc. (Schwartz 2006). At ancient times, types of kitchen utensils varied outstandingly from household to household. The inventory of London kitchen appliances that survived in the fourteenth century shows the application of kitchen utensils. Similarly, in Minnesota in the second half of the nineteenth century, John North is recorded as having himself made “a real nice rolling pin, and a pudding stick” for his wife, whereas an immigrant Swedish family is recorded as having brought with them “solid silver knives, forks, and spoons. Quantities of copper and brass utensils burnished until they were like mirrors hung in rows” (Kreidberg 1975). The nineteenth century, particularly in the USA, saw an explosion in the number of kitchen utensils available on the market, with many labor-saving devices being invented and patented throughout the century. Maria Parloa’s Cook Book and Marketing Guide listed a minimum of 139 kitchen utensils without which a contemporary kitchen would not be considered properly furnished. Parloa wrote that “the homemaker will find that there is continually something new to be bought” (J. M. Volo and D. D. Volo 2007). A growth in the range of kitchen utensils available can be traced through the growth in the range of utensils recommended to the aspiring householder in cookbooks as the century progressed. Earlier in the century, in 1828, Frances Byerley Parkes had recommended a smaller array of utensils. By 1858, Elizabeth H. Putnam, in Mrs Putnam’s Receipt Book and Young Housekeeper’s Assistant, wrote with the assumption that her readers would have the “usual quantity of utensils,” such as copper saucepans, well lined, with covers, from three to six different sizes, a flat-bottomed soup-pot, an upright gridiron, sheet-iron bread pans instead of tin, a griddle, Hector’s double boiler, a tin coffeepot for boiling coffee, or a filter—either being equally good, a tin canister to keep roasted and ground coffee in, a canister for tea, a covered tin box for bread, a spoon-tray, etc. (Williams 2006). Obviously, the history of the European kitchen is fascinating (see Table 1.3). It is sensible that the kitchen has undergone many technological and social changes in the past few years. The kitchen we know today is an indispensable component to contemporary life. Today’s kitchen is often open to the family and dining rooms, and it is the natural gathering place when entertaining. Homeowners today are demanding large kitchen plans with plenty of space for baking, cooking, and hosting. Double islands, walk-in pantries, and specialty appliances keep kitchen remodelers busy (Reagan 2015). However, the European kitchens were not luxurious and unlike today’s kitchen, they were not rooms where people wanted to spend time in, historically. They were dark and prone to catching fire; they were filled with noises, messes, and smells. For these reasons, kitchens tended to be situated as far away as possible from the social or private rooms in a home (Reagan 2015). Today, with time goes by, kitchen appliances refer to the appliances and tools used for cooking and eating. Kitchen appliances can be divided into commercial

(continued)

A sixteenth-century Tudor manor kitchen. The oversized hearth served as a multitasking feature, used for cooking, roasting, heating In the Middle Ages (in Europe this spanned the fifth–fifteen centuries), life centered on the always-lit open fireplace. Smoke and soot were a constant bother for eyes and lungs. Romans had used brick tubes to draw out smoke, and the earliest example of a chimney in England was 1185 But smoke and soot remained a huge problem until the sixteenth century when chimneys became widely used in homes. With a chimney, smoke was drawn up and out of the great hall, making it easier to breathe and easier to create large cooking fires in fireplaces. But the large, brick chimney and fireplace effectively divided this great room, creating two rooms: the living room (where guests were received and business conducted), and the kitchen

Sixteenth century

Description A recreated twelfth-century kitchen range at Dover castle. This was an open-style kitchen, lacking a chimney to draw smoke out of the great hall In European communal societies of ages past, cooking was essentially done over an open fire within a one-room home or within the great hall of a larger structure. All manner of life revolved around the cooking area, which was the primary source of heat, light, and safety. Over time, the general layout of the home changed and the central, great hall was subdivided

Typical kitchens

Twelfth century

Period

Table 1.3 History and development of the European kitchens (Reagan 2015)

24 1 Cooking History and Development of Kitchen Appliances

Eighteenth century

Period

Typical kitchens

Table 1.3 (continued)

(continued)

An eighteenth-century kitchen. Notice the round wheel above the fireplace, this would have held a turnspit dog. Specifically bred for this task, the device would spin the wheel and turn the spit for roasted meats Economic trends and politics had a major influence on the design and function of the kitchen. The eighteenth and nineteenth centuries saw an influence of the French style of cooking (both in England and America), with elaborate dishes, formal table settings, and strict etiquette. Increased trade between Europe, the Americas, and Asia brought new foods and new demands to the kitchen. Servants were necessary to not only cook but also take care of and clean the increasing amounts of cutlery, dishware, gadgets, and ovens

Description

1.4 Kitchen History and Development 25

Early 1900s

Period

Typical kitchens

Table 1.3 (continued)

(continued)

A Hoosier cabinet from the early 1900s created a more efficient kitchen design with its built-in features, extra storage, and additional workspace The industrial revolution spurred new inventions, cheaper prices, and new ways of thinking like economic and ergonomic efficiency. In 1899, the Hoosier manufacturing company was formed and they introduced a freestanding kitchen storage piece, known as the Hoosier cabinet. It incorporated space-saving features like upper and lower cabinetry, in-cabinet storage spaces for things like flour and sugar, and often featured a pullout work surface. Although the Hoosier cabinet was not large, it filled the storage void for the homemaker and made working in the kitchen that much more efficient

Description

26 1 Cooking History and Development of Kitchen Appliances

1960s

Period

Typical kitchens

Table 1.3 (continued)

(continued)

This kitchen is large and functional and features a more open layout, perfect for cooking and entertaining The kitchen became a source for honing culinary crafts, displaying designer cookware and served as the hub for social activity. By the 1980s, the idea of a completely open kitchen, with appliances designed to show off, came into being. The trophy kitchen was born

Description

1.4 Kitchen History and Development 27

Twenty-first century

Period

Typical kitchens

Table 1.3 (continued)

A contemporary kitchen layout with the kitchen opens to the dining area and family room Kitchens are being used as testing grounds for new ideas, and swarms of bloggers and entrepreneurs are entering the food crafting marketplace. There is also a parallel trend toward connectivity, integrated appliances, and using wireless technology throughout the home. Refrigerators can tell our phones that we are out of milk and our tablets can monitor our recipes and food intake

Description

28 1 Cooking History and Development of Kitchen Appliances

1.4 Kitchen History and Development

(a)

29

(b)

Fig. 1.19 Present kitchens. a Residential kitchen, b commercial kitchen

kitchen appliances and residential kitchen appliances with respect to different using occasions. Commercial kitchen appliances are generally used for hotels, restaurants, hospitals, educational and workplace facilities, and similar establishments while residential kitchen appliances are for home. According to the function, kitchen appliances are grouped into five groups: storage appliances that used to store food and utensils, such as refrigerators, freezers, cupboard, wash appliances, including hot and cold water supply system, wash basin, wash cabinet, drainage pipe, garbage bin, and so on, processing equipment, such as chopping board, steamed bread machine, noodle machine, cutting machine, meat grinder, juicer, etc., cooking appliances, mainly including the furniture in the dining room and the utensils and appliances for eating like bowls, plates, cups, pots, dishes, chopsticks, spoon, knife, fork, etc. (Ruan 2014). Generally, a present or contemporary residential kitchen (see Fig. 1.19a) is typically equipped with a stove, a sink with hot and cold running water, a refrigerator, counters and kitchen cabinets arranged according to a modular design. Many households have a microwave oven, a dishwasher, and other electric appliances. A present commercial kitchen (see Fig. 1.19b) is generally larger and equipped with bigger and more heavy-duty equipment than a residential kitchen. For example, a large restaurant may have a huge walk-in refrigerator and a large commercial dishwasher machine. Commercial kitchens are generally subject to public health laws. They are inspected periodically by public health officials and forced to close if they do not meet hygienic requirements mandated by law. It should be pointed out, today, in Chinese urban area, in order to make a maximum utilization of limited land resources, the development of architectures has a tendency to be multi-storey or high-rise buildings. On the other hand, the development of steel structure and the emergence of the elevator have contributed to the construction of multi-storey buildings. Due to the presence of the passenger elevator, the construction gradually made a breakthrough beyond five-layer height limitation (the feasible ascent distance on foot) after the nineteenth century. From then on, the high-rise building has experienced more than a century of vigorous development.

30

(a)

1 Cooking History and Development of Kitchen Appliances

(b)

Fig. 1.20 Centralized exhaust shaft in high-rise residential buildings. a Shaft structure in high-rise residential building, b field test of exhaust duct with range hoods. Reprinted from reference Li et al. (2017), Copyright 2017, with permission from Elsevier

Currently, the kitchen which located in the new high-rise building is installed central exhaust shaft (see Fig. 1.20a). Equal section exhaust duct is one of the most common forms in the design of kitchen ventilation. Due to its good exhaust effect, low-cost system, facilitate construction, and other advantages, the central exhaust ducts are widely used in the actual project. Field test of exhaust duct with range hoods was shown in Fig. 1.20b. It should be pointed out that high-rise structures pose serious challenges to HVAC designs. High-rise buildings of multi-dwelling units have been widely used as a residential building in China. Most of cooking exhaust shafts in high-rise residential building takes the form of central exhaust system. The inconsistence of exhaust airflow rate of kitchen hoods often leads to reverse flow and taint of odor in central exhaust shaft, which decreases the performance of kitchen hoods.

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Chapter 2

Kitchen Ventilation Requirements

Abstract This chapter mainly covers the kitchen ventilation requirements, including fundamental natural ventilation and mechanical ventilation principle, and evaluation of kitchen indoor air quality. The emphasis of this chapter has been laid on the theoretical analyses and engineering practice.

2.1 Pollutants The human health and welfare consequences of air pollution are the major reasons for our scientific concern about the atmospheric environment. Indoor environments constitute a small fraction of the atmosphere. However, most of the air that is breathed by humans on a daily basis is breathed indoors. As investigated by Nazaroff et al. (2003), the primary, nonreactive species emitted into an indoor atmosphere is roughly 1000 times more likely to be inhaled than if that same species is emitted into outdoor air. The attributes of the global, urban, and indoor atmospheres are presented in Tables 2.1 and 2.2, and the tables compare some parameters that influence pollutant behavior in urban and indoor environments. Consequently, surface transformations, including redox reactions, particle deposition, and sorption phenomena, take on unusual significance indoors. Cooking is an important source of indoor air pollution. In indoor environment, 43.2% of the microparticles and 52.5% of the microparticles exposure were from

Table 2.1 Some attributes of the global, urban, and indoor atmospheres Environment

Mass, kg

Flow, qm (kg/d)

Mass b (kg/d) breathed,qm

b Ratio, qm

Global atmosphere

5 × 1018

–

~1011

–

~1012

~1013

Urban atmospheres Indoor atmospheres

~1015

~3 ×

1015

~4 × ~8 ×

1010

~10−5

1010

~10−2

Reprinted from Nazaroff et al. (2003), Copyright 2003, with permission from Elsevier Notes For the urban and indoor atmospheres, attributes are summed over all environments on earth. For the global and urban atmospheres, the mass breathed includes air inside and outside of buildings © Springer Nature Singapore Pte Ltd. 2019 A. Li and R. Kosonen, Kitchen Pollutants Control and Ventilation, https://doi.org/10.1007/978-981-13-6496-9_2

33

34 Table 2.2 Some attributes of urban and indoor atmospheres

2 Kitchen Ventilation Requirements

Parameter

Urban atmosphere

Indoor atmosphere

Residence time

~10 h

~1 h

Light-energy flux

~1000 W/m2 (day time)

~1 W/m2

Surface–volume ratio

~0.01 m2 /m3

~3 m2 /m3

Precipitation

~10–150 cm/year

Absent

Reprinted from Nazaroff et al. (2003), Copyright 2003, with permission from Elsevier

the cooking process (Zhao et al. 2006; Chowdhury et al. 2012; Pervez et al. 2012). In urban environments, cooking particles can also contaminate outdoor air. Studies showed that 10–30% of organic carbon in urban air comes from cooking emissions (Schauer et al. 1996; Robinson et al. 2006; Zheng et al. 2006; Wang et al. 2009). The organic aerosol emissions from cooking accounted for 24.4% of the total mass of atmospheric organic matter in Beijing (Huang 2010). In Los Angeles city, 20% of the PM2.5 in the atmosphere comes from cooking fumes (Schauer 2000). Besides, 20–75% polycyclic aromatic hydrocarbons (PAHs) in the atmosphere come from the cooking process (Venkataraman 1994). To some extent, cooking is more dangerous than other sources of air pollution, such as industrial, energy, and agricultural pollution, where cooking is more susceptible to inhalation or contact with the skin. Cooking fumes are mainly composed of particles, oil droplets, water in food, combustion products, and composition. The surface of particles is generally attached to organic matter, such as polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and aldehydes. Epidemiological studies have shown that exposure to these pests increases the risk of some diseases, including respiratory infections, pneumonia, tuberculosis, chronic obstructive pulmonary disease, lung cancer, asthma, and cardiovascular diseases (Kim et al. 2011). Earlier studies have also reported increased mortality from respiratory diseases such asthma, emphysema, lung function abnormalities, and lung cancer in the employees of hotels and restaurants (Svendsen et al. 2002; Riihimaki et al. 2002; Mahembe et al. 2010; Ko et al. 1997). Previous studies indicated that Asian-style cooking emits more particulate matter than Western-style cooking (Lee et al. 2001; Levy et al. 2001; He et al. 2004). In China, the kitchen possesses the most delicate culinary skills in controlling the degree of cooking (heat, temperature, or duration). Since China’s local dishes have their own typical characteristics, generally including many heavy load cooking techniques: deep-frying, quick-frying, crisp-frying, pan-frying, stir-frying, boiling, stewing, steaming, roasting, smoking, etc., some dishes require much edible oil or lard for cooking. In addition, a wide range of seasoning is applied, especially for commercial kitchens. Therefore, the emissions from different styles of cooking operation might make a quite significant contribution to indoor air pollution in Chinese-style restaurants (Li et al. 2012). Oils are usually first heated to high temperatures in a wok (large metal pan with raised sides) to increase dish flavors,

2.1 Pollutants

35

resulting in large emissions of effluent. The effluent includes smoke, grease particles, and vapor, products of combustion, heat, and moisture (Bramfitt 2006). There is a higher incidence of lung cancer in Chinese women than in Western (Maclennan et al. 1977; Gao et al. 1987; Seow et al. 2000). These women smoke little but contact lung cancer rather frequently. Epidemiological surveys indicated that indoor air contamination deriving from cooking practices might be an important risk factor for lung cancer in Chinese women (Wu-Williams et al. 1990). The composition of cooking fumes is highly diverse, depending upon factors such as fuels, raw food composition, cooking oil, cooking temperature, and cooking style (Abdullahi et al. 2013). Several fuels are used for cooking throughout the world, including biomass (e.g., wood or charcoal), coal, kerosene, natural gas, liquefied petroleum gas (LPG), and electrical energy (˙I¸sler and Karaosmano˘glu 2008). Cooking fuels are one of the most important sources of indoor air pollution, particularly in developing countries (Ellegard 1996; Kim et al. 2011). The impact of biomass fuel smoke on respiratory and other diseases is shown in Fig. 2.1. Most fire-based cooking is based on the combustion of fuel types that can also increase overall health risks. A total of 393 kitchen workers from 53 Chinese restaurants were once surveyed (Wong et al. 2011). The results showed that the poorer lung function and higher prevalence of respiratory symptoms among workers in gas-fueled kitchens compared to those in electricity powered kitchens may be associated with exposure to higher concentrations of toxic air pollutants generated during gas cooking.

Fig. 2.1 Impact of biomass fuel smoke on respiratory and other diseases

36

2 Kitchen Ventilation Requirements

Numerous studies have identified the relationships between the properties of airborne particulate matter and human health (Atkinson et al. 2001; Franck et al. 2011; Langkulsen et al. 2006). A number of epidemiological studies have associated negative health impacts with particle mass concentration (Pope 2000; Samet et al. 2000; Hauck et al. 2004; Samoli et al. 2005; Pope and Dockery 2006); for example, Samoli et al. (2005) estimate the PM-mortality association with data from 22 European cities participating in the APHEA (Air Pollution and Health-A European Approach) project using regression spline models, as depicted in Fig. 2.2. Scientific studies found that increasing the mass concentration of particulate matter increased the mortality rate (Samet et al. 2000; Polichetti et al. 2009). Additionally, particles in the PM1.0 size fraction (i.e., with an aerodynamic diameter of less than 1.0 µm) are more dangerous to human health because they adversely impact the human respiratory, circulatory, and cardiovascular systems (Caggiano et al. 2010; Cheng et al. 2011). The adverse health effects associated with particulate matter (PM) not only depend on the physical properties (e.g., particle size and number, total surface area, and electrostatic properties), but also related to the chemical and biological compositions of the PM (Gemenetzis et al. 2006; Rajasekar and Balasubramanian 2011; Oeder et al. 2012). Toxicologists found that many hazardous airborne species emitted during cooking processes are potential human carcinogens (Shields et al. 1995). Moreover, despite the fact that the elemental mass fraction of the PM is small, trace elements, such as Pb, As, Se, Cd, and Hg, may pose serious threats to human health, and, more specifically, they may cause inflammation, lung and heart diseases, or DNA damage because toxins, including heavy metals, are absorbed onto the large surface area of the PM2.5 (Gemenetzis et al. 2006; Senlin et al. 2008). There are scholars who proposed that the poor lung functions in kitchen workers can be due to single or combined association with indoor air pollutants, CO, PAHs, TVOCs (Wong et al. 2011) in Tables 2.3 and 2.4. The VOCs emissions from oils heated in woks are mutagenic in several in vitro short-term test systems, and con-

Fig. 2.2 PM-mortality association to data from 22 European cities. Reprinted from reference Pope and Dockery (2006), by permission of Taylor & Francis Ltd.

2.1 Pollutants

37

Table 2.3 Lung function in kitchen workers by fuel use and stove exposure Stove exposure

Lung function parameter

Adjusted mean (liters, BTPS) Kitchens using electricity, E (n = 115)

Kitchens using gas, G (n = 278)

Percentage difference (%) 100 × (E − G)/G

Stove-exposed, n = 283

FVC

3.40 (0.06)

3.25 (0.04)

4.62

FEV1

2.85 (0.05)

2.70 (0.04)

5.56

Non-exposed, n = 110

FVC

2.93 (0.10)

2.88 (0.07)

1.74

FEV1

2.44 (0.09)

2.33 (0.07)

4.72

Both groups, n = 393

FVC

3.27 (0.05)

3.15 (0.03)

3.81

FEV1

2.74 (0.05)

2.60 (0.03)

5.38

Notes Analysis of covariance was used, adjusting for age, gender, height, the smoking habits of the workers and their family members, and, for stove-exposed and non-exposed groups combined, stove exposure. Numbers in parentheses denote standard errors. FVC forced vital capacity, FEV 1 forced expiratory volume in 1 s

sistent positive associations are found between the risk of lung cancer and a variety of indices of exposure to indoor air pollution arising from Chinese-style cooking (Zhong et al. 1999). A cross-sectional study was conducted on 94 kitchen workers employed at commercial kitchen in Lucknow city, North India, by Singh et al. (2016). The results showed that the exposure to PM, VOCs, and PAHs in indoor air and presence of urinary PAHs metabolites may lead to inflammation, which can cause microalbuminuria in kitchen workers.

2.2 Natural Ventilation Principle 2.2.1 Flow Characteristics of Openings When a difference in pressure is applied across an opening, a flow of air takes place through the opening in a kitchen. The aerodynamics of this flow is complex but, by classifying openings within two general types, it is possible to specify simple formula to relate the flow rate to the pressure difference. The categories are: (a) cracks, or small openings with a typical dimension less than approximately 10 mm, (b) openings with a typical dimension larger than approximately 10 mm. For cracks, the airflow rate q can be described commonly in the following form: q = kwl(P)n

(2.1)

38

2 Kitchen Ventilation Requirements

Table 2.4 Prevalence of respiratory symptoms in kitchen workers Respiratory symptom

Kitchens using electricity (n = 115)

Kitchens using gas (n = 278)

Adjusteda OR (95% CI)

Cough in the past month

11 (9.6%)

31 (11.2%)

1.11 (0.52–2.80)

Regular cough

8 (7.0%)

18 (6.5%)

1.34 (0.54–3.36)

Phlegm in the past month

14 (12.2%)

43 (15.5%)

1.29 (0.64–2.64)

Regular phlegm

7 (6.1%)

25 (9.0%)

2.70 (1.01–7.23)

Frequent wheeze

1 (0.9%)

9 (3.2%)

3.43 (0.41–28.85)

Breathlessness while walking up slope

45 (39.1%)

94 (33.8%)

0.73 (0.45–1.18)

Chest cold

16 (13.9%)

33 (11.9%)

0.69 (0.35–1.38)

Eye pain, watery eyes, red eyes

11 (9.6%)

34 (12.2%)

1.51 (0.69–3.30)

Runny nose in the past month

13 (11.3%)

31 (11.2%)

1.09 (0.51–2.31)

Sore throat in the past month

7 (6.1%)

38 (13.7%)

2.33 (0.96–5.66)

Note a Binary logistic regression was used, adjusting for age, gender, height, the smoking habits of the workers and their family members, and stove exposure

where l is the length of the crack, m, the P is the applied pressure difference, Pa, and k w is window leakage factor which is related to the crack forms. A suitable value for n is 0.67. For larger openings: q = Cd A(2P/ρ)1/2

(2.2)

It is conventional to assign a value to the discharge coefficient, C d , corresponding to that for a sharp-edged orifice, taken here as 0.61. The value of A for other types of opening then becomes the equivalent area associated with that particular opening (BS 5925-1991). Ventilation is used in buildings to create thermally comfortable environment with acceptable indoor air quality by regulating indoor air parameters, such as air temperature, relative humidity, air speed, and chemical species concentrations in the air (Chen 2009). Natural ventilation is a process of supplying air to and removing air from an indoor space without using mechanical systems. It refers to the flow of external air to an indoor space as a result of pressure differences arising from natural forces. As shown in Table 2.5, there are three types of natural ventilation occurring in buildings, which are wind-driven ventilation, buoyancy-driven ventilation, and hybrid ventilation. Wind-driven ventilation arises from the different pressures created by wind around a building or structure, and openings being formed on the

2.2 Natural Ventilation Principle

39

Table 2.5 Principle of natural ventilation of a building (BS 5925-1991) Conditions

Schematic representation

(a) Wind only

Formula qw = Cd Aw vt (Cp1 − Cp2 )1/2 1 A2w

(b) Temperature difference only

1 (A1 +A2 )2

qt = C d A b 1 A2b

(c) Wind and temperature difference together

=

=



+

2T gh T¯

1 (A1 +A3 )2

+

1 (A3 +A4 )2

1/2 1 (A2 +A4 )2

q = qt , for √vr T

< 1/2  1/2  h 0.26 AAwb Cp1 −Cp2 q = qw , for √vr T

> 1/2  1/2  h 0.26 AAwb Cp1 −Cp2 Notes A1 , A2 , A3 , A4 , Ab , Aw equivalent area of specific openings denoted in the text, C d discharge coefficient for an opening (default value 0.61), C p surface pressure coefficient, g acceleration due to gravity, h vertical distance between the centers of two openings in a wall, vr reference wind speed, T absolute temperature, q airflow rate, qt airflow rate due to the effect of temperature only, qw airflow rate due to the effect of wind only, T¯ Average of inside and outside air temperatures It should be appreciated that, in practice, some openings exist unintentionally, e.g., junctions between building components, and that such openings will contribute to the ventilation actually achieved

perimeter which then permit flow through the building. Buoyancy-driven ventilation occurs as a result of the directional buoyancy force that results from temperature differences between the interior and exterior (Linden 1999). Since the internal heat gains which create temperature differences between the interior and exterior are created by natural processes including the heat from people, wind effects are variable, and naturally ventilated buildings are sometimes called “breathing buildings.”

2.2.2 Wind-Driven Ventilation The static pressure of air is the pressure in a free-flowing air stream and is depicted by isobars in weather maps. Differences in static pressure arise from global and microclimate thermal phenomena and create the air flow entitled wind. Dynamic

40

2 Kitchen Ventilation Requirements

pressure is the pressure exerted when the wind comes into contact with an object such as a hill or a building. The pressure distribution on a building is in connection with the shape of building and the direction of wind (Clancy 1975). The wind on a building affects the ventilation and infiltration rates through it and associates with heat losses or heat gains. Wind speed increases with height rising and is lower toward the ground due to frictional drag. Wind-driven ventilation depends on wind performance, the interactions with the building envelope as well as openings or other air exchange devices such as inlets or chimneys. The impact of wind on the building pattern creates positive pressure on the windward side of a building and negative pressure on the leeward side of a building. Thus, building shape and local wind patterns are crucial in creating the wind pressures that will drive air flow through its apertures. In practical, wind pressure will vary considerably and create complex air flows and turbulence by the interaction with elements of the natural environment (trees, hills) and urban context (buildings, structures). Vernacular and traditional buildings in different climatic regions rely heavily on natural ventilation for maintaining thermal comfort conditions in the enclosed spaces. Due to the difference in mean pressures between the windward and leeward faces, air flows in through the openings A1 and A2 , and out through A3 and A4 . Aw is the effective equivalent area of the four openings, and the details are illustrated in Table 2.5. It can be seen that openings in parallel can be added together arithmetically, while those in series should be obtained from the reciprocal of their squares. It may also be noted that ventilation rate is proportional to wind speed and to the square root of the applied differential mean pressure coefficient. Thus, a range of from 0.1 to 1.0, a ratio of 10, gives only a ratio of approximately 3 for the change in ventilation rate for the same wind speed. Higher values are typical of exposed building, whereas lower values are more typical of sheltered buildings (BS 5925-1991).

2.2.3 Buoyancy-Driven Ventilation Buoyancy-driven ventilation arises due to density differences of interior and exterior air, which is directly caused by temperature differences. When there is a temperature difference between two adjoining airflow rates, the warmer air will have lower density and be much lighter, and thus it will rise above the cold air producing an upward air stream. Forced buoyancy-driven ventilation in a building usually takes place in a traditional fireplace. Passive stack ventilators are common in most bathrooms and other types of spaces without direct access to the outdoors. In Fig. 2.3, the air flows in at the lower openings A2 and A4 and out through A1 and A3 . The equivalent area is now Ab . The formula given in Table 2.5 shows that ventilation rate is proportional to both temperature difference and height between openings (BS 5925-1991). Buoyancy-driven ventilation increases with temperature difference, as well as the height of rising between the higher and lower apertures in displacement ventilation. When both high- and low-level openings are fixed, the neutral plane in a building can be obtained at the location between the high and low openings at which the internal pressure will be the same as the external pressure (in the absence of wind-driven). It

2.2 Natural Ventilation Principle

41

is demonstrated that above the neutral plane, the internal air pressure will be positive and air will flow out of any intermediate-level apertures, while below the neutral plane, the internal air pressure will be negative and external air will be drawn into the space through any intermediate-level apertures.

2.2.4 Hybrid Ventilation Hybrid ventilation is wind-driven coupled buoyancy-driven ventilation. For the simple case under consideration, at low temperatures the flow pattern is similar to that for wind alone. If the temperature is increased, keeping wind speed constant, the combined effect of wind and temperature difference is to enhance the flow through the lower windward and upper leeward openings and to reduce the flow in the upper windward and lower leeward openings. Eventually, in this example, the flow in the upper windward and lower leeward openings becomes zero and as the temperature difference increases further it reverses, approaching a flow pattern typical of temperature difference acting alone. Even for this simple example, the ventilation rate of the space due to the action of both wind and temperature difference is not easy to calculate. But a reasonable approximation can be made by calculating the airflow rates expected for the two conditions acting separately and taking the larger to apply r , given in Table 2.5, determines whether to the combined case. The expression √vT wind or temperature difference will dominate. The form of this expression indicates that taller, or more sheltered, buildings will tend to have natural ventilation rates independent of wind speed for a large part of the colder months of the year (BS 5925-1991). The chimney presented in Fig. 2.4 is a traditional as well as one of the most important natural ventilation devices to exhaust smoke in rural areas. When the people’s living environment is very poor, the smoke exhaust effect is not solved very well. People usually make a fire outside the house, then moved it to the house for

Fig. 2.3 Arrangement of openings in a simple building (BS 5925-1991)

42

2 Kitchen Ventilation Requirements

Fig. 2.4 Chimney in the rural kitchen (Zhang 2005)

cooking, so it can avoid the problem that the smoke cannot be exhausted from room (Zhang 2005). Tracing to kitchen history, Qin and Han dynasties are very important periods for the ancient Chinese kitchen development. At that time, people started to set up the fire stove on the ground with stones, which also called the fixed fire stove hearth (kitchen stove). And after that, people have used this kind of kitchen stove more than two thousand years. The main function of chimney is making the fire drawn, exhausting the smoke and improving the combustion conditions. The chimney plays an important role in full combustion of fuel, heat energy utilization, and exhaust flow inside the stove chimney (Zheng 2011). In Qidong district of Jiangsu Province, the economic model of this region is still predominantly based on agriculture. In this region, there are rich agricultural resources, so the traditional farmhouse kitchen burning method still is widely used. For example, the three-burner stove shown in Fig. 2.5 is typically used in the farmer’s home. Chinese Kang is associated with the stoves in the traditional rural and the northern district which is called “warm bed” (see Fig. 2.6). One side of the Kang leads to the chimney, the other side equipped with cooking stoves, and the two sides are connected with the exhaust flue. Part of the working principle of the Kang is the same as the stove. The waste heat of smoke that generated from cooking process entered the body of the Kang from the inlet, heated the Kang body, and finally exhausted through the chimney. The chimney has two effects on natural ventilation. On the one hand, it is driven by the thermal pressure to exhaust smoke and powered the smoke flow enter the Kang. On the other hand, it caused a negative pressure inside the Kang which will avoid the smoke infiltrate into the room and destruct the indoor air quality. Instead of using the originally single form stove, the heat generated during cooking can be reused along the flue which is a way to recycle energy. In 2006, Chinese archaeologist found a fire Kang of the Western Han dynasty period; hence, the time for the Kang’s history has been moved up for 2000 years.

2.2 Natural Ventilation Principle

43

Fig. 2.5 Structure of the three-burner stove (Zheng 2011)

(a)

(b)

Fig. 2.6 Chinese Kang. a Structure (Zheng 2011), b schematic of typical Kang. Reprinted from reference Li et al. (2016), Copyright 2015, with permission from Elsevier

In another word, as early as the Western Han dynasty (202 B.C.–8 A.D.) of China, the people in the central plains of China had invented Kang. The formative period of the stove was just takes place during the Han dynasty, which confirmed by a close relationship with Kang. In another aspect, “Chimney,” as an important tool of natural ventilation, was introduced to Western Europe from the East more than 1200 years ago. Gradually, from the imperial palace to the ordinary families, the cooking and heating activities both have to be equipped with a chimney. And up till

44

2 Kitchen Ventilation Requirements

now, researchers are still taking a long time to study how to improve the performance of chimney. From the end of the eighteenth century to the end of the nineteenth century, the industrial revolution in Europe and the USA brought the development of productivity and economic prosperity. In this period, with the urbanization rapidly growing, the urban building with modern kitchens grows at a high speed. Tamura and Wilson (1967) investigated the pressure difference caused by the chimney effect in high-rise buildings. Murakami et al. (1990) analyzed the pressure distributions in a centralized shaft through numerical method. They conducted a model experiment and provided comprehensive results on the pressure distributions. Kwon and Ahn (2009) improved the exhaust performance of kitchen hoods by controlling the pressure distributions in a shaft through the use of roof fans and on-off dampers at each story. Han (2010) analyzed various system parameters that affect the pressure distribution in a centralized shaft in high-rise buildings and investigated the correlations between these parameters. In recent years, some progress has been made in residential kitchen ventilation, available calculation method to analysis centralized exhaust system of kitchens in the multi-story and high-rise residential buildings was proposed, see Chap. 9. With the improvement in people’s living condition, the mechanical technology as well as the sealed performance of doors and windows merely by natural ventilation method already cannot satisfy the requirement of people for good air quality, especially for the houses that needs airtight doors and windows during summer cooling and winter heating stage. At present, the ventilation rate of nature ventilation is still difficult to control. However, during the winter, the ventilation rate through opening a window far exceeds the ventilation rate that maintains the indoor air quality, which can cause heat loss in winter.

2.3 Mechanical Ventilation Principle Mechanical ventilation is the intentional movement of air into and out of a building using fans, intake and exhaust vents. The power produced in mechanical ventilation is provided by a fan, which neglects the influence of outdoor environment. A mechanical ventilation system mainly consists of fans, ducts, and air openings. The ventilation pattern in mechanical ventilation can be classified as mixing ventilation, displacement ventilation, and local ventilation. Mixing ventilation is an expression for an air distribution pattern, and not a ventilation system. It can also be called an air distribution pattern with mixing effect or mixing air distribution. Mixing room air distribution aims for diluting of polluted and warm/cool room air with cleaner and cooler/warmer supply air. The air is supplied to the room with high initial mean velocity, and the established velocity gradients generate high turbulence intensity aiming to promote good mixing and uniform temperature and pollution distribution in the occupied zone (Muller et al. 2013). Besides, the reverse flow region is near the working zone so that the wind velocity and tem-

2.3 Mechanical Ventilation Principle

45

46

2 Kitchen Ventilation Requirements

Fig. 2.8 Drawing and a photograph of the hood of typical Chinese commercial kitchens. a Photograph, b drawing

to flow backward frequently. In addition, the installation fan on the outside walls of the building really affects overall aesthetics, especially in the high-rise residential buildings in the city. On the other hand, the exhaust smoke from different storys could be mutual diffused, which may even spread to neighboring buildings and affect other residents’ health. The most unfavorable situation is if all residents around the building use this kind of fan to exhaust cooking oil fumes, it is easy to form a cross contamination. At present, a reasonable and widely accepted method is installing the exhaust hood above the kitchen stove in the household. By controlling the fan speed of the exhaust hood, the emitted cooking oil fumes can be collected to the centralized exhaust shaft in each story of building and removed outside through an exhaust cowl (see Fig. 1.19a). It is an efficient method to remove contaminant in the high-rise residential buildings. At present, the size of the kitchen hoods is standardized in residential kitchen; however, in the commercial kitchen, exhaust hoods need to be designed according to hearth arrangement. The front lower edges of the hoods of the restaurant’s overhang are set to the 1.8 m as measured vertically from the finished floor. In addition, the smoke from cooking in restaurants is withdrawn through the hood, and the grease and impurities are partly captured from the exhaust air using the baffle-type grease filter. Finally, grease and contaminant that have been removed and flow into a drain channel which connected with a collection tray. In order to avoid the grease emitting from cooking and adhering to the hood and finally falling into the wok, the front lower edge of the hood is designed at about 30°. So, the grease can fall down along the edge of the hood and flow into a drain channel and orients the collection tap. The baffles and the front edge of the hood constitute a triangle that would reduce the exhaust efficiency because of the small hood volume. A drawing and a photograph of the hood are shown in Fig. 2.8. Air conditioning system becomes more and more common in commercial kitchen. The main functions of air conditioning system in the commercial kitchen are to provide enough air for person breathing, exhaust the pollution generated during cooking process in the kitchen, remove the indoor waste heat and moisture, especially the

2.3 Mechanical Ventilation Principle

47

waste heat that transferred from cooking area to the interior space by heat convection and radiation, creating suitable thermal environment for kitchen work.

2.4 Evaluation of Kitchen Indoor Air Quality 2.4.1 Evaluation Indexes Indoor air quality (IAQ) is a multi-disciplinary phenomenon and is determined by the many pathways in which physical, chemical, and biological contaminants eventually become a portion of the total indoor environmental composition. According to US EPA (U.S. Environmental Protection Agency), IAQ refers to “the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants.” It defined elements of good indoor climate as: (a) ensuring adequate ventilation (introduction and distribution of clean indoor air), (b) controlling contaminants traveling in the air, and (c) maintaining acceptable thermal comfort. Considering the importance of air quality inside the kitchen, several researchers studied the evaluation indexes of IAQ parameters which are reviewed in this section. IAQ has been receiving more and more attention, and increasing interest has been directed toward controlling of indoor obnoxious gases such as CO2 and CO. (Saha et al. 2012). Normally, the quality of indoor air is evaluated by means of parameters such as airflow rate, air change rate (ACH), CO2 concentration, air change effectiveness (ACE), and mean age of air (MAA). Indoor air quality is an essential determinant of people’s health. In a kitchen, the air quality is affected by contaminants (including particulate matter (PM), carbon monoxide, carbon dioxide, volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons) released from the cooking processes, and microbial contamination in kitchens. The contaminants emissions are related to different recipes, cooking approaches (such as frying, roasting, and grilling), food materials (and ingredients), fuel types, and extraction/ventilation equipment. Indoor exposure to air pollutants causes very significant damage to health globally—especially in developing countries (WHO 2010). Due to the health effects of indoor air pollutants, most governments/organizations have published regulations for risk assessment and risk prevention. Some standards (GB 3095-2012; US EPA 201A; EU 2008) are showed in Tables 2.6, 2.7, 2.8, and 2.9. There are no specific requirements of air quality for commercial kitchens. However, three standards were introduced to evaluate the indoor air quality for residential kitchens. Table 2.10 is a summary of the ASHRAE 62.1 (ASHRAE 2013), 62.2 (ASHRAE 2013), and (EN 15251 2007) standards with the main parameters recommended for IAQ evaluation. It should be noted that the European standard (EN 15251 2007) contains the largest number of parameters related to the evaluation of IAQ. Therefore, the standard (EN 15251 2007) with an acceptable satisfaction level

48

2 Kitchen Ventilation Requirements

Table 2.6 Ambient air particulate matter (PM10 , PM2.5 ) concentration standards (GB 3095-2012; US EPA. 201A; EU 2008) China standard (µg/m3 )

American standard (µg/m3 )

EU standards (µg/m3 )

Annual mean

24-h average

Annual mean

24-h average

Annual mean

24-h average

PM10

70

150

–

150

40

50

PM2.5

35

75

12

35

25

–

Particulate matter

was recommended. This standard also considers that the humidification of indoor air is usually not necessary, while ASHRAE 62.1 suggests a maximum limit of 65% for relative humidity, which was used as upper comfort limit.

2.4.2 Improvement of Kitchen Indoor Air Quality IAQ has been receiving more and more attention, and increasing interest has been directed toward controlling of indoor obnoxious gases such as CO2 and CO. In a commercial kitchen, working conditions are especially demanding. The air quality is affected by high emission rate of contaminants released from the cooking processes. Ventilation plays an important role in providing comfortable and productive working conditions and in securing contaminant removal. In the present work, a detailed analysis is performed to study the distribution of pollutants and temperature. One difficulty when attempting to predict the detailed indoor air flow is that there are many factors which influence or govern the flow. It is affected by the details of the air distribution design, building construction, outdoor environment, and the presence and activities of the human beings occupying the space, among many other factors. When designing and analyzing heating, ventilation, and air conditioning (HVAC) systems, engineers and scientists generally have at their disposal three tools to study the indoor air flow patterns: analytical model, fullscale or small-scale model measurements, and computational fluid dynamics (CFD). Analytical models are usually restricted by the need for simplifying assumptions and simplistic configurations. Full-scale measurements can provide the most reliable data but are most expensive and difficult (or mostly impossible) to perform. Extrapolation from small-scale model data to a real size room or building is limited by scaling difficulties. CFD seems to be a general and accessible method, but it still needs to face several challenges. For the application of CFD to indoor air flow, the challenges include modeling the physics of the flow including turbulence, specifying realistic boundary conditions, representing the complex geometry of the room, and developing accurate and efficient numerical algorithms. At present, the studies on the indoor environment of residential and commercial kitchens mainly focused on the chemical and physical properties of various

Pollutants

Benzene

Toluene

Xylene

Formaldehyde

Acetaldehyde

Acrolein

Naphthalene

Styrene

Benzo[a]pyrene

Benzo (a) anthracene

Benzo (b) fluoranthene

Benzo (k) fluoranthene

Benzo (1,2,3-cd) pyrene

CO

NO2

SO2

No.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

–

–

–

0.39

0.39

0.39

0.39

3.9

–

0.12

–

0.01

0.021

–

–

0.1

Tumor Slope Factor (kg d−1 mg−1 )

–

–

–

–

–

–

–

–

–

–

0.7

300

9

–

–

3

8-h reference exposure limits (RELs) (µg m−3 )

660

470

23,000

–

–

–

–

–

21,000

–

2.5

470

55

22,000

37,000

27

Acute reference exposure limits (RELs) (µg m−3 )

–

–

–

–

–

–

–

–

900

9

0.35

140

9

700

300

3

Chronic reference exposure limits (RELs)(µg m−3 )

Table 2.7 OEHHA regulation of indoor concentrations of common cooking contaminants (OEHHA 2008, 2009)

–

–

–

–

–

0.096

0.033

0.06

–

5.8

–

90

40

–

–

13

No significant risk level (NSRL)—inhalation (µg d−1 )

2.4 Evaluation of Kitchen Indoor Air Quality 49

50 Table 2.8 WHO regulation of indoor concentrations of common cooking contaminants (WHO 2000, 2010)

2 Kitchen Ventilation Requirements

No.

Pollutants

Standard value (mg/m3 )

Average time

1

Carbon monoxide

100

15-min average

60

30-min average

30

1-h average

2

Dichloromethane 3 mg/m3 0.45

mg/m3

24-h average Weekly average

3

Formaldehyde

0.1 mg/m3

30-min average

4

Nitrogen dioxide

200 µg/m3

1-h average

Styrene

0.26 mg/m3

Weekly average

6

Toluene

0.26

mg/m3

Weekly average

7

Naphthalene

0.01 mg/m3

5

40

µg/m3

Annual mean

Annual mean

pollutants and its pathogenic that emitted during cooking process. The dangers of extreme thermal environment to the employees in kitchen are often ignored. Indoor air pollution in developing nations is a major health hazard (Bruce et al. 2000). A major source of indoor air pollution in developing countries is the burning of biomass (e.g., wood, charcoal, dung, or crop residue) for heating and cooking (Duflo et al. 2008). The resulting exposure to high levels of particulate matter resulted in between 1.5 million and 2 million deaths in 2000 (Ezzati and Kammen 2002). A good indoor air quality in a kitchen not only enhances the enjoyment of the kitchen surroundings, but also protects the health of cooks from exposure to harmful air pollutants (Lee et al. 2001). The air quality is affected by high emission rate of contaminants released from the cooking processes. In general, improved ventilation is the most efficient strategy to improve indoor air quality. Room air distribution systems, like other HVAC systems, are intended to achieve required thermal comfort and ventilation for space occupants and processes. The air quality is affected by high emission rate of contaminants released from the cooking processes. Ventilation is used in buildings to create thermally comfortable environments with acceptable IAQ by regulating indoor air parameters, such as air temperature, relative humidity, air speed, and chemical species concentrations in the air (Pitarma et al. 2016). The role of ventilation has also been supported by various studies (BalKrishnan et al. 2004; Dasgupta et al. 2006; Huq et al. 2004). Moreover, better combustion technology and automatic wood burning stoves are suitable for low-carbon dwellings and meet the remaining heat demand (Carvalho et al. 2013). Open or well-ventilated kitchen conditions lower the pollutant concentration. It is better to adopt such kitchen settings (by the means of poor family) rather than switching to more expensive clean fuels to cost-effective cleaner fuel in the rural areas (Begum et al. 2009). Natural ventilation is the movement of air through openings (trickles or valves) in the building, due to wind or static pressures created by differences in temperature

2.4 Evaluation of Kitchen Indoor Air Quality Table 2.9 Standard values of indoor pollutants in China National Standard (GB/T 18883-2002)

51

No.

Pollutants

Standard values

Average time

1

Sulfur dioxide

0.50 mg/m3

1-h average

2

Nitrogen dioxide

0.24 mg/m3

1-h average

3

Carbon monoxide

10 mg/m3

1-h average

4

Carbon dioxide

0.10%

24-h average

5

Ammonia

0.20 mg/m3

1-h average

6

Formaldehyde

0.10 mg/m3

1-h average

7

Benzene

0.11 mg/m3

1-h average

8

Toluene

0.20 mg/m3

1-h average

9

Xylene

0.20 mg/m3

1-h average

10

Benzo [a] pyrene

1.0 ng/m3

24-h average

11

Nitrogen oxide

0.01 mg/m3

24-h average

12

TVOC

0.60 mg/m3

8-h average

14

Total number of bacteria

2500 cfh/m3

–

15

222 Rn

400 Bq/m3

Annual mean

between the interior and exterior of the building (generally known as “stack” effect), or to a combination of these acting together. Opening windows and doors, operating window or attic fans, when the weather permits, or running a window air conditioner with the vent control open increases the outdoor ventilation rate (see Fig. 2.9). Furthermore, there are several methods of mechanical ventilation, the simplest being the supply or extraction of air from space using a fan (see Fig. 2.10). In these cases, an adequate opening should be supplied to allow the exit or entry of air, in order that the fan can operate satisfactorily. More complex systems involve the use of ducted air supply from centrally located fans, possibly providing supply and extraction of air, conditioning of the air, and heat recovery from the extracted air. The main advantage of mechanical ventilation is its controllability. Mechanical ventilation is a strategy with a high impact on the quality of the indoor air of a building and the comfort of users, since it is difficult or even impossible for

N/C

N/C

47–93 m2 : 1 bedroom 21 l/s and 2 bedrooms 35 l/s Hallways 30 l/s per 100 m2

0.42 l/s. m2

ASHRAE 62.2

EN 15251

Note N/C—Not Counted

N/C

2.5 l/s per person or 0.3 l/s per m2

ASHRAE 62.1

Average air speed (m/s)

Air change rate

Standard

7 l/s

N/C

N/C

1 l/s. m2

Supply airflow

25 l/s

Bathroom >15–20% 15 l/s

20 l/s

10 l/s

Kitchen

5 ach

Continuous

50 l/s

80% (Fig. 3.24) of the total amount of PAHs in the commercial cooking emissions (Chen et al. 2007), which was consistent with the result of 76–90% in earlier study (Zhu and Wang 2003). The emission profiles for both gaseous and particulate phase PAHs from controlled cooking styles were shown in Fig. 3.25. Among of them in gaseous phase, naphthalene (67–89%) was the most abundant PAH in all of the exhaust samples, and the contribution of acenaphthylene was significantly higher in emissions from the Chinese restaurants, whereas fluorene was higher in emissions from the

3.4 Chemical Properties of Cooking Pollutants

103

Fig. 3.25 Gaseous and particulate PAH emission profiles for deep-frying, steaming, and mixed cooking styles (combination of steaming and frying) in a staff canteen study. Reproduced from reference Chen et al. (2007) by permission of The Royal Society of Chemistry

Western-style cooking restaurants (Chen et al. 2007). The relatively low proportion PAH compounds in Chinese emissions were observed by See and Balasubramanian (2006a) when they made a health risk assessment of occupational exposure to PAH associated with Chinese, Malay, and Indian cooking. They found that Malay cooking emitted higher PAH concentrations and also a larger fraction of PAH in PM2.5 (600 ng/m3 and 0.25%, respectively) than the other methods (Chinese, 141 ng/m3 and 0.07%, Indian, 37.9 ng/m3 and 0.02%, respectively) (See and Balasubramanian. 2006a). PAH compounds with different numbers of rings have been observed to exhibit different toxicity values, and PAHs with numerous rings were found to be more toxic than those with fewer rings (Zhu and Wang 2003). The 3-ring PAHs were the most abundant fraction in the exhaust of the Western-style cooking restaurants, accounting for 25–57% (see Fig. 3.26) of total measured particulate PAHs. Meanwhile, the Chinese restaurants had a lower value in the 3-ring fraction (>42%), while higher contributions (>60%) of heavier PAHs (4-rings and above) were found for the Chinese restaurants, and PAHs with higher molecular weight are associated with higher toxic equivalent factors (Chen et al. 2007).

104

3 Pollutions of Cooking Oil Fume and Health Risks

Fig. 3.26 Distribution of particulate PAHs based on the number of rings in the exhausts of sampled commercial kitchens: CR—Chinese restaurant, WR—Western restaurant, FR—Western fast-food restaurant. Reproduced from reference Chen et al. (2007) by permission of The Royal Society of Chemistry

Fig. 3.27 Distribution characteristics of PAHs with different ring numbers in edible oils after different deep-frying periods: DPF—deep-fried potatoes, DFCN—deep-fried chicken nuggets. Reprinted from reference Hao et al. (2016), Copyright 2016, with permission from Elsevier

To further understand the relationship between the ring number distribution of PAHs and the cooking methods, the changes of 16 PAHs ring quantities percentage (2-, 3-, 4-, 5-, and 6-ring) when using four kinds of edible oils (see Fig. 3.27) were examined by Hao et al. (2016) and the ring number percentage for diverse edible oils and cooking methods (see Fig. 3.28) was examined by Yao et al. (2015). In addition, the kitchen type (see Fig. 3.29) was also related to the ring number distribution of PAHs (Zhu and Wang 2003).

3.4 Chemical Properties of Cooking Pollutants

105

Fig. 3.28 Percentages of PAHs by ring number: RO—rapeseed oil, SO—soybean oil, PO—peanut oil, OO—olive oil, DPF—deep-fried potatoes, DFCN—deep-fried chicken nuggets, FE—fried eggs, and FH—fried hairtails. Reprinted with the permission from reference Yao et al. (2015), Copyright 2007 American Chemical Society 80 Commercial kitchens Domestic kitchens Oil fumes Cooking practice

Distribution of different PAHs (%)

70 60 50 40 30 20 10 0

2-ring

3-ring

4-ring

5-ring

Fig. 3.29 Distribution of 2-, 3-, 4-, and 5-ring PAHs in oil fume and in air of commercial and domestic kitchens. Reprinted from reference Zhu and Wang (2003), Copyright 2012, with permission from Elsevier

Another study illustrated that all four fresh (unused) edible oils contain PAHs (189.9–2754.8 mg/kg) and mainly low-ring (2- to 4-ring) PAHs and its concentrations (see Fig. 3.27) in the edible oils increased with increasing deep-frying time, especially among the high-ring (5-ring and above; see Fig. 3.30) PAHs (Hao et al. 2016). According to the size distribution, the particulate PAHs emitted from grilled fish were collected and divided into three particle size ranges (>10, 10–2.5,