Engineering Design Handbook - Criteria for Environmental Control of Mobile Systems

Citation preview

Downloaded from http://www.everyspec.com

UNCLASSIFIED

AD NUMBER AD889588

NEW LIMITATION CHANGE

TO Approved for public release, unlimited

distribution

FROM Distribution authorized to U.S. Gov't. agencies only; Test and Evaluation; SEP 1971. Other requests shall be referred to Army Materiel Command, Attn: AMCRD-TV, Washington, DC 20315.

AUTHORITY USAMC ltr,

14 Jan 1972

THIS PAGE IS UNCLASSIFIED

Downloaded from http://www.everyspec.com

""NIAMC PAMPNLET

AiCP N-120

m =

m

00

i

00

ENGINEERING DESIGN

i•

HANDBOOK

Sm

0 CRITERIA FOR ENVIRONMENTAL CONTROL OF MOBILE SYSTEMS

°.. ".4

I

for ti.-

to

HEASi ARTERS, IU.. ARMY UA!I;aiI COMMAND "

at• :A,,x •

-r•i

Downloaded from http://www.everyspec.com

Best

Available Copy

Downloaded from http://www.everyspec.com

HEADQUARTERS UNITED STATES ARMY MATERIEL COMMAND WASHINGTON. D.C. 20315 AMC PAMPHLET NO. 706-120

16 zepLember 1971

ENGINEERING DESIGN HANDBOOK CRITERIA FOR ENVIRONMENTAL CONTROL OF MOBILE SYSTEMS Paragraph

page LIST OF ILLUSTRATIONS ............... LIST OF TABLES .... ....... ............. PREFACE ...............................

vu X1 xii

CHAPTER I. TYPES OF ENVIRONMENT'AL CONTROL REQUIREMENTIS 1-1

1-4

Introduction ........................ Temperature Lontrol ....................... Humidity Control ........................ Ventilation ...............................

!-5

Control of Contaminants and Odors ...........

1-6

Noise and Vibrations ....................... References ...............................

1-2 1-3

......

.I-! ..

-2

1-2 1-4

.1-5

11-6

CHAPTER 2. TYPES OF INSTALLATIONS

2-1

Introduction .............................

2-1

2-2

Floor .................................

2-1

-t

2

W.dI

2-4 2-4.1 2-4.2 2- 5

Interior-extenor .......................... ingle-packap .......................... Multi-eckage .... ....................... Muitiplc-unit ........................... Renote Unit ........... ............ Reference .............. ................

2-I 2-3 2-3 2-5 ... Z2-8

CHAPTER 3. TYPES OF MILITARY AIR CONDITIONERS 3 1 3- 2 3- 3 3 -4 3-5 3 6

Introductiqu ...... ....................... Single- and Multi-packa Units . Configuration (Horizontal and Vertical) ......... ('ontinumnt and Intermittent Operation ......... Electric-powered and Gasoline-cngine-driven .... Skid- and Trailer-mounted ................. Reference ..... ....... . .. . .-

3-1 1-1 1............. 3-1 3- 4 3--6 3-6 3......

Downloaded from http://www.everyspec.com

TABLE OF CONTENTS MCon't) Parwnph

Pare

CHAPTER 4. FEATURES OF MILITARY AiR CONDITIONERS 4-1I

Introduction ...

4- 2 4- 2.1 4 - 2.2 4-2.3 42.64

Service Versatility Cooling Capacity .............. Heating 'CapLhility .............. Ventilation ...... ....................... Colectivne ProteVction Compatibility i..... .....

4 -2. 5

4- 16 4-3 4t-4 4- 5 4-6 4-7 4-8

...

4

Compatibility With Sensitive Electronic Systems .

Tolerance of Variations in tho: Power Supp!y .... Easm of Operation .. ....................... Mobility ............................... Riabllity and Durabgity .................... Maintenance .............................. Installation .......................... Storage ................................. References ...............................

...

1

4 1 4 1 4 2 4- 2 4-2 4-3

4--3 4-3 4-3 4-4 4 -5 4-6 4-6 4-6

CHAPTER 5. TYPES OF MILITARY HEATERS 5-I 5-2 5-3

Introduction .............................. Electric Heatenrs ........................... Combustion Heaters ....................... R'-nces ................... ...........

5-I 5-1 5-3 5-5

CHAPTER 6. FEATURES OF MILITARY HEATERS 6-i 6-2 6-3 6-4 6-5 6-5.1 6 -_.

Introduction ............................ Service Versatility ......................... Ease of Openraion .......................... Muh~ty ............................... Reliab9ity and Dumbiity .................... Otiec s ............................... Features Contributing to Reliability and

6-6• 6- 6.1 6-6.2 6-63 6- 7 6. 8

Maintennce ............................ Three Maintenance Categories ............... Maintenance Tine Objectives .............. Features Contributing to Eas of Maintenanc. Installation ............................. Sto age ........ .............. .......... References ........................... .

Duability .............

.....

6-I 6- 1 6-2 6-2 6-2 6-2

.. .... o-3 6-3 6-4 6-4 6--5 -S

CHAPTER 7. METHODS OF MINIMIZING COOLING AND HlEATING LOADS 7- i

Imution ...........................

7-1

Downloaded from http://www.everyspec.com

AMttP 7tMI2

TABLE OF CONTENTS (Cn't.)

SParagraph 7 2 7 2.1 7-__ 7-2.3 7- 2.4 7 -3 7 -4 7- 5 7- o

Page Reduction of Solar Load .............. General ... .......... . . .. .. ..... . Reduction of Window Are. .................. Shading ............ ...................Increasing Reflectivity of Exeinor Surfaces ... Independent Ventilation of Heat-rele~ng Lquipnient .............................. Recirculation of Air from Heat-releasing Equipment ......... ................... Ventilation Independent of Environmental Control System ................................. Elficient Lighling System .................... References ...............................

7-I 7 1 2 t

7 3 7- 3 7-4 7-6 7- 6 7-6

CHAPTER 8. CRITERIA FOR SELECTION O1 ENVIRONMENTAL CONTROL UNITS 8-1 8-2 8- 2.1 8-2.2 8-2.3 8-3 8-3.1 8-3.2 8-3.3 8-4 8-5 8-5.1 8-5.2

Introduction ........................... Perfommnce Requirements .................. Determination of Requirements .............. onbined Hnin and Cooling Units vs Separate Units .......................... Nonstandard Units ........................ Electrical Liritations .................... Power-supply OCaracteristics ................ Power Rating ............................ Electrical Inteffernce ..................... Physical Limitations ..................... Transportation Livwi -tnou .................. Mobility ................................ Vibration .............................. References ...............................

. .

..

8- 1 h- 1 8- 1 8- 2 8-2 8-3 8-3 8-3ý 8-3 8-3 8-4 8-4 8-4 8-4

CHAPTER 9. INSTALLATION GUIDES 9-I

Introduction ..............................

9-2

General Arrangement of Environmental Control

9-2.1 9- 2.2 9-2.3

9-3 9 -3.1 9 -3.1.1 9-3.1.2 9-3.1.3

9-i

System ........................... ..... Chor c ietww Free Discharge and Duct System ................................ Location of Ewironmevntal Control Units ...... lyp"a System Layouts .................. ..

Mountins Desi* ..................... Types of Mouni-4 ........................ Introduction ....................... Throuetthe-wall Mounting ................ Exterior Mounting .....................

9_19-i 9-1 9-2

9-2 ....

9-2 9-2 9-5 9-5 Wi

Downloaded from http://www.everyspec.com

AMC*

ft120 TABLE OF CONTSENTS I',on'.) Pnras~h - - 3. !.4 9 3 1.5

9-3.1.6 9--3.2 9- 3.3 9- 3.3.1 9-3.3.2 9-3.3.3 9--3.3.4 9-3.4 9-4 9-4.1 9-4.2 9-4.3 9-4.4 9-4.5 9-4.5.1 9-4.5.2 9-5

Interior-vxterior Mounting ............ Reractabr e Mount! ....................

tieater Mountiog

....

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

VibiJt!Qn Control ... .. ................. Exte ralConnectios ....... .......... Eleitrical Connectiorns .................. Condensate Drain ........................ ...... Fuel and Exhaust Connections .. Reirigerant Pining ........ ............. Provions fm Trnsportation ................ Air Distributitm nti (iCrculation .............. Introduction ............................. Air Distribution Systems ................... General Ru!.s of Ventilation ............... Methods of Av'oiding Objectionably High Air Velocities .............................. Heating Systems .......................... Air Distribution With and Without DIauwork ........................... Conditions in Polar Regions ................ E&uct Desg ..............................

9 9 9- 9

9-9 9-9 9-13 9- 13 9 19 9-19 9-24 9-24 9- 24 9- 24 9- 25 9- 28 9- 28 9-29 9-29 9-29 9-30

9- 5.1 9-5.2

General Rules of Duct Design ................ Design Velocitis ........................

9-30 9-31

9-5.3

Design Procedure ........................

9-31

9-5.4

Duct Fabrication .........................

9-5.5

Supply Outlets ...........................

7-32 9-36

9-5.6

Ducts for Remote Units ....................

9-5.7

Selection of Duct Material ..................

9-36 9-36

9-6 9-6.1 9-6.2 9-6.3

Controls. ..... .... ..................... Control Panel ............................ Thermostat .............................. Dampen ................................

9--36 9-36 9-39 9-39

9-6.4 9-7

Auxiliary Controls . ...................... Safety Cowvidetatiom .......................

9-40 9-40

9-7.1 9-7.2 9--7.3

Introduction ...................... ...... Combustion Heater Opention ............... Emergency Override Switch .................

9-40 9-40 9-41

9-7., 9-8

Safety Prcautiom ........................ Maintenance ftovis .....................

9-A! 9-43

9-8.i

Introduction .............................

9-43

9-8.2 9-8.3 9-8&4 9-9 9-9.) 9-9.2 9-9.3

iy

Page

Acc~ensib ity ............................. Coding of FIo and Receptacks ............ Protecxio Against Deterioation ............ N"osie Contf.l .......................... Intoduction ............................ Air Noie Control ....................... Mechci¢l Noise Control ..................

9-47 9-48 9-48 9-49 9-49 9-49 9-50

Downloaded from http://www.everyspec.com

TABLE OF CO

Ref..........

ENTS (QCWnt0

. . . ....

..

9 53

......

(CIAPTEk 10. CXWLING OF ELECTRONIC EQUIPMENT

10 I 10 2

Cooling Methods .................... .... Computation of Cooling Requa-ements ....... Referenc .......... .....................

1010, 2 10-4

CHAPTER 1I. CHEMICAL, BIOLOGICAL, AND NAMAOLOGICAL CON'SiDERATaONS 11I- I 11-2 11 -2.1 11i- 2.2

Introduction .......................... ... C-nrud Cotsideratiom of Collective Protection... Kind& of Contamiation .................... Airflow Requirenents .....................

11-2.34ti ............................ 11! - 2.4 Perttm w ............................ I1-215 Ckeso Rooins ............................ 11 3 Collezke cftwti:or System Components ....... I -i.! Introd ction ............................. 11-3.2 Air Inlet Protector ........................ 11-3.3 Prefilter ................................ 11-3.4 Blower .......................... 11-3.5 Particulate Fiters ......................... 11-3.6 Gas Fdter ............................. 11-3.7 Filter Units ............................. 11-3.8 Control of Pre ure ....................... 11-3.9 Contrls ............................... 11-3.10 Protective Entrances ....................... 11-4 Installation and Mounting ................... Refetrences ............................... GLOSSARY ............................. ABBREVIATIONS .........................

I11- I 1[1-3 11-3 11i- 3 11-3 I 1 ! -3 11-4 11-4 11-4 11-5 11-5 11-5 11-5 11-6 I1-6 11-6 11-7 11-7 11-9 11-15 G- I G-4

APPENDXES APPENDIX A- FUNDAMENTALS AA- 2 A-3

The sychrowetk Chart .................... Overall W--t rarnder Coefficent .............. Meav (i Reliability .............. ........ References ...............................

A-I A-i A-3 A-3

APPENDIX 9. VESIGN CRITERIA -I

Clinwtk Desi

Crikeds ....................

.9-1

Downloaded from http://www.everyspec.com

AMCP 7WI20

TABLE OF CONTENTS MCon't.} P.•.ngrapthPa

B 2 B 3 8- 4

Aflowa]e ('arbon Munoxd (concntrations Noiw LveI Specifications ....... Effect of Noie on Verbal Coammunca3tio n

3

Refefencce•

4

....

........

.

APPENDIX C. DESIGN PRKO'EVURES C- I C -1. 1 C- 1.2 C. 1.3 C-- 1 4

-ta"trmnation of Envirow.rentWa Control R[qu!, ment .......... n...... .. . ntiofProccdul .. .. Latent Heat Load Considerations ...... Environnicntal Requirements for Equipment an~d Activities . .................

Performunce Variation With Aititt,,b-

..

C- 2 C-3

CalcuLation of Cooling Requirer-,ent .. Exampic of Air Conditoner Selection.......

C-4

Calculation of Heating and Cooling for M.19 Van ............ Interior Design Air Condition ......... .. Exterior Des. Air Condition ............ Heat Load C.Iculation .......... ...... Alignment Chart for Calculating Coolin- Loads ... Refe•rences .......................... ...

C-4.1 C- 4. 2 C- 4.3 C'- 5

"

3

(". C C-18 (

20

APPENDIX D. AiR CONDITIONER TOPICS D- I

"D-2

T-chnical Characteristics for Air Conditioning. Van Type ......................... . Refrigerant Circuit With Hot-ps Bypass........... References . ..................... ........

D I 1) 2 -4

APPENDIX E. COLLECTIVE PROTEC-TION SYSTEM (CPS) FOR COMMAND POST VEHICLF Reference ..............

I

..

.

.

F 1

Downloaded from http://www.everyspec.com

LIST OF ILLUSTRATIONS Fig. No.

TIdle

Page

I I

Cha.rt 1for IDct-rinining, lffective lempupatme for I _2 Normially ('lothed, Sedentary Individuals .... I2 Revised ASIIRAF Comfort Chart ...... .......... 1- 3 21 The loor-mounted Installat ions of 15,000 FBtu/hr Heater ................ ..... TW 0io 0,00(0 vitt/hr hleate~rs Mounted Jriid'. 2 FExpansible Var' .. . . . . .. . . . . 2) ,000 nm/hfr Air Conditioner Mounted Through Wall of Air Trantsportahle Hut..................2--3 9 ,000 Btu/hr Air C'onditioner Mount d Through Van Wa!] Witt, Half Iniside and Half Outside 2- 3 the Van............... ................... 25 Frequently Used Configuration%for Mounting 2--4 18.000 Btu/hr, Multi-package Air Conditioner ... 20 Illustrations; of Thrý!e Mounting C'onfith'.rat.-ons of 18.000 Btu/hr Multi-package Air Conditioner 2-_S 27 Illustration of' 9,000 Btu/hr Air Conditioner Mounted Outside an Inflatable Shelter 2- 6 Employing Flexible Ducts for. Air now .... 2--8 View of 60,000 Btu/iir Gasol ine-engine-d riven Air .Conditioner With Duct Storage Compartment 2-7 3--1 Example of A,- Conditioner With Separate Conden-s.ýr and §-vaporator Se!ctions (6,000 3-3 Btu/hr NMulti-packa_,e Air. Cinditioner) ........... 3_4 3 2 18.000 lltu/hr Multi-packagc Air Conditioner . ... 3-3 Two Examples of Sirgl.!J 1cg Air Conditioners . 3--5 5-- 1 60.000 Btu/hr Gasoline-burning Heater ......... 5--4 150,000 IBtu/hr Pot table Duc:t.'ype Heaiter .... 5- 7- 1 Example of the Use of Shading to Reduce Solar Heating of Air Conditioners ................... 7 -3 7- 2 Method of Ventilating Heat-releasing Equipment 7_-S to Reduce Environmental Control Loads .... uI Typical Air Distfihution Arrangements for Traihkrs ............................ ...... 9-3 9_2 Typ';.--l Heating and Air-conditioning Installation in Semi-trailer Using Vertical Ducts .............. 9--6 9- 3 Typical Heating and Air-conditioning Installation 9- 7 in Semni-trailer Using Horizontal Ducts ............ 9-.4 Through-the-wall Installation of Air Condi' ioner,;...............................9-8 9- 5 Door-mounted Environmental Control Unit ...... , Hinged Air Conditioner Mountinig Which Permits 9 6 Swinging for Servicing ....................... 9- 10 9-_7 Large Air Conditioner Mounted on Van With Detachable Frame................. ......... 9_Il 9 Installation of Multi-unit Air Conditioner..........9 - I 2 Vii

Downloaded from http://www.everyspec.com

AMCP 706-120

LIST OF ILLUSTRATIONS (Con't.) Fig. No. 9) 9

Tit.

Pave"

Wall-mounted lfeater and Air Conditioner in Shelter ..................................

9

13

"9 10

Exterior Mounting of Condenser Section of 6.000 ltu/hr Air Conditioner Showing Power Cables arid Refrigerant Lines ................ "9 I !(A) Elevation Views of Air Conditioner and Heater Installation in Shop Van .............. 9 - I I(B) Inside Isometric View of Air Conditioner :and Heater Ilistallation in Shop Van .............. 9- 1I (C) Outside Isometric View of Air Conditioner and Heater Instdllation in Shop Van .... ......... 9-- 12 Telescoping Rail Installation .................. 9- 13 Heater Mounted on Floor of Shelter ........... 9-- 14 Floor-mounted Space Heater With Quickdisconnect Fuel Adapter ................... 9- 15 Space Heater Mounted on Floor of Shelter ...... 9-16 Pedestal-mounted, Gasoline-burning Heater ...... Heater Fuel Line With Quick-disconnect Fittings. 9- 17 "--18

9- 19 9- 20 9-21 9-22

9-23 9-24 9-25 9--26 -

9-27 9-28 9-29 9- 30 9-31 9-32

Viii..

9 14 9_ 15 9 16 9- 17 9 18 9 -19 .

9-20 9 21 9- 22 9

-23

Clearance for Vibration Control in

Through-the-wall Installation ................ 9 24 Method of Passing Power Cable Between Condenser arnd Evaporator Sections of Multipl -unit Installation .............................. 9 25 Method of Connecting Condensate Drain to 9-- 20 Air-conditioning Uni ...................... Method of Attaching Condensate Drain to Heater Exhaust Line ....................... .9-_26 Fitting for Connecting Refrigerant Line

Through Shelter Wall ...................... 9- 27 Arrangements for Protecting Exterior Openings in the Envihonmental Control System During Transit ............ ............. ....... 9-- 28 I,1asic Air Distribution Problem ................. 9-29 Illustration of Poor and Good Duct Design ...... 9.31 Friction of Air in Straight Ducts for Volumes of 10 to 2,000 cfm ........................ 9- 33 Portion of Heater Discharge Ducl in Semi-trailer . 9-_37 Heater Duct Transition Piece ...............* *-39 Heater and Air Conditioner Installation Wilh Connecting Ductwork in Semi-trailer .......... 9 40 View of Semi-trailer Environmental Control Installation .............................. 9- 4 1 Heater and Air Conditioner Discharge Ducts in Semi-trailer .............................. .9 42 Completed Installation of I:ivironmental Control Ductwork in Semi-trailer .............. .... . 9 43

Downloaded from http://www.everyspec.com A

't."

ýXj- IX Ut

LIST OF ILLUSTRATIONS (Con't.) Fig. No. 9 33 9 34 9 35 9 30 9 37

Q..- 38 9-39

Title

lakv

View of Ventilation System for Magneti-: Iape U nit . ....... ..... .... .. ...... .. .... .... Interior View of Shop Van Showing l:lectronic Equipment and Environmental Control Units ... View of Completed Van Installation ........... Conversior Materials Required for Flexible Duct Application ............................. Drawing Showing Cani-lock Arrangement for Conne-ting Flexible Duct to Plen!p ...........

Drawing Showing Method of Attachinz, Flexible Duct to Female (onnector With Metal Ring Clamp ................................ %-'tachments for Attenuating Noise at Intake and Discharge Openings of Ernviron mental ('Cntrol

9. 4 4 V 45 9 46 9-46 9 47

. 9-48

U nits ..................................

9-40 10- 1

.9- 5 1

I!--8

Attenuation of Noise in Discharge Ductwork ..... Diagram To Illustrate Solution of Problem on Cooling of Electronic Apparatu, ........... Category A Collective lProtection ....... ...... Exploded Views of Two Concepts for Modular Configurations of Coll,:ctive Protection Equipment .............................. Recommended Gas-particulate Filter Unit ((;PFU) Design Air Flows and Ranges ......... Air Inlet Prote'ctor ......................... Straight-flow Dust Separator Tube Cyclone Principle ................................ Cyclone Arrangements for Continuous I)ust R em oval ..... ........................... Typical Panel-type Particulate Filter Construction ............................ Typical Lates!-design Gas Filt.,r ...............

I - ) II - 11

H --9

Air Purification Unit .......................

11

1 -.10 1 - II H - 12 11 13

Parallel Ar,nangcment of Three GI'FU's ..........

I - I I1 --2 11-3 1 1-4 II -5 11

-

o

1 I--7

9-52 10 3 11 2 11 3 1I1 11

Typical ('PE Air Distribution Methods .......... Schematic Drawing of Collective Protection

I ! 7 I1 8

Syst•m With Booster Blower ................

Schematic Drawing of Shelter (olleciive Protectior System With Air (Conditionerand Filter Unit Miounted on rrailer ..............

A- I

U.S. Army Psychrometric Ch:rt ........

B.- I

Fffect of Noise, Separation, and Voice I Oe'el -n Person-to-person Communiication .......... Plan View of SI 4i Shelter ................... Revised ASHRAF. Comfort (':arW .............

C-- I C-..,

5

- 13

1 13 . I - 14 I1 15

Antibackdraft Valves .......................

I1 - 14

4

.....

..

I 1-

I6

11

17

A- 2

B--4 . C- 3 . C--10 ix

Downloaded from http://www.everyspec.com

LIST OF ILLUSTRATIONS (Con't) Fig \0 ( (

4

•

( C k D E

5 6 I I

T-itle Psychtometnrc Probabdityhr"j Heat Source-. Smks. and Surface fieat Transfer in M29 2 Van Extenor Surfaces of S129Q Van Psychro-mtnc Density ('hat Air (onditionng Load ( •ilulator Nomogaph Refrigerant Flow Dagram Recommended Collective Protection System for M292 Fxpa'ndable Van

Npe (

-

ilI

(

-

12

C 14 C 17 C 19 D- 3 E 2

Downloaded from http://www.everyspec.com

AMCP 706-120 LIST OF TABLES Table No. 3

I

3-2 4- 1 4- 2 5-1 o ---I 9-1 99-3 9-4 9-5 I 1--I 11-2 11--3 11 -4 B-I B-2 B-3

C-I C-2 C-3 C-4

C- 5 C(6 C-7 C-8 ('-9 C-_10

Title Specifications of Military Environmental Control U nits .................................. Future Environmental Control Units ........... Cooling Capacity Specification for 60,000 Btu/hr Vertical, Compact Air Conditioner ............ Maintenance Time Objectives for Military Air Conditioners .......................... Specifications of Military Heaters .............. Maintenance Time Objectives for Military Heaters Recommended and Maximum Duct Velocities for Conventional Systems ..................... Circular Equivalents of Rectangular Du%,is for Equal Friction and Capacity ................. Recommended Construction for Rectangular Low Pressure Ducts ........................... General Characteristics of Outlets ............. Transmission Constants for Typical Isolators ..... Dust Concentrations for Different Transport Conditions .............................. Existing Particulate Filters for Collective Protection Systems ........................ Existing Gas Filters for Collective Protection Systems ........................ Standard CB Filter Units ..................... Maximum Allowable Concentrations of Carbon Monoxide ............................... Maximum Steady State Noise Level for Army Materiel Command Equipment ............... Maximum Steady State Noise Level for Nonelectrically Aided Person-to-person Communication .......................... Temperature and Humidity Requirements for Typical Equipment and Activities ............ Total Equivalent Temperature Differentials for Walls for April 20 and August 24 .............. Compact-'!nit Cooling Capacities (Btu/hr) at 1.0 Sensible Heat Ratio and Free Delivery ......... Compact-unit Cooling Capacities and SHR at Nominal Military Conditioned Air Design Conditions .............................. Cooling Correction Factors .................. Cooling and SHR Correction Factors ............ Conditioned Air Fan Performance - CFM ....... Psychrometric Conditions at 99.9% Probability ... Corrected Equivalent Temperature Differences ... rotal Heat Load Calculations. Summer Condition: M292 Van .....................

Page

3- 2 3-4 4-2 4-5 5-2 6--4 9-31 9-34 9-35 9-38 9-52 ! 1-6 11 - 10 . I 10 I1 - 12 B-2 B-2

B-3 C-2 C-5 C-7

C-8 C--8 C- 8 C-8 C-1 2 C- 14 ('-15 xi

Downloaded from http://www.everyspec.com

PREFACE Th, Engineermg Design Handbook Series of the Army Materiel (ommand 3 coordinated series of handbook; contaming basit information ani fundamental data useful in the design and development of Army materiel and systems. The handbooks are authoritative reference books of practical information and quantitative facts helpful in the design and development of Army materiel so that it will meet the tactical and the technical needs of the Armed Frces. IS

The purpose of this handbook is to help fill the need for comprehensnme technical documents for regulating the environmental control of mobile systems, such as shelters. vans. and trailers. As used in this handbook. environmernal control refers to the regulation of the temperature. cleanhness. and purity of the air in the controlled space, it also includes regulation of the noise and vibration genera!ed by the environmental control equipment. Following an introductory chapter covering the different aspects of environmental control and a chapter on types of installations. most of the first half of the handbook consists of chapters which describe the military air conditioners and heaters, and the criteria for selecting them. A major chapter nffers guides on the insta•t!ion. of en'rironmental control systems Other chapters discuss methods of minimizing heating and cooling loads and the cooling of electronic equipment. which represent the major demand for environmental control in mobile systems. A final chapter considers coilectise protection equipment for chemical and biological contaminants. Various design data and sample design calculation.appendixes.

..

... '"d tn

The Handbooks are readily available to all elements of AMC. including personnel and contractors having a need and/ot requirement. The Army Materiel Command policy is to release these Engineering Design Handbooks to other DOD activities and their contractors and to other Government agencies in accordance with current Army Regulation "0-31. dated Q September 196f Procedures for acquiring these Handbooks follo% 2. Activities within AMC and oth" offictal form from

DOD agenckes ordV direct on an

Commanding Officer Letterkenny Army Depot ATTN AMXLE-ATD Chambetsburg. Pennsylvania 17"201

3W

Downloaded from http://www.everyspec.com

b Contractors who have Department of Defense contracts should submit thtr requests through their contracltng officer with proper justification to the addte listed m par a. c. Government agencies other than DOD havirg need for the Handbooks may submit their request directly to the address listed in par a or to Commanding (;eneral v. S. Army Materiel Command ATTN AM(AM-ABS Washington. D.C. 20315 d. Industries not having (Government contracts (this includes colleges and universities) must forward their requests to Commanding General U.S. Army Materiel Command ATTN: AMCRD-TV Washington. D.C. 20315 e. All foreign requests must be submitted through the Washir•!on. D.C. Embassy to: Assistant Chief o6 Staff for Intelligence

ATTN: Foreign Liaison Office Department of the Army Washington. D.C. 20310 All requests. other than those originaetig within DOD. must be accompanied by a valid justification.

Comments and suuestions on this handbook are welcome and should be addressed to Army Reserch Office-Durham. Box CM. Duke Station. Durham. North Carolina 27'06.

Xul

Downloaded from http://www.everyspec.com

CHAPTER I

TYPES OF ENVIRONMENTAL CONTROL REQUIREMENTS

1-1

INTRODUCIiON

In its broadest sense. environmental •.ontroi entails reguTation of the temperature. prossure. density. cleanliness, and putity of the gas in the controlled space; control )f the concentratiops of its componenlt, paiculry water vapor: the circulation and distribution of the gas; and also the control of noise and vibration. Environmental control also involves ~Envro-n,-ental ~ wa rn~ gpollutants provisions forproviions~ detectin and ing against their critict accumulations which c-uld cause humaH incapacitation or death. The term "air conditioning" cowrs only the r€ocess of treatig air so as to control simau.1nteously its temperature, nhui~aiy, And diMtrision to meet the requirements of the conditioned space. As used in this handbook, environmental

control has two major purposes: (I) Toinovide a tolerabne habitat wher degradation of human performance is mi and also to enhance survival under extreme conditions. (2) To provide optimum environmental conditions for materials and equipment operation. These conditions may be incompatible in special cases. For instance, in locations where food is being pocemed. temperatures new the freezing point are desiable to tetard spoilage while a room temperature above 6OF is favorable for personnel. In cames of such mutually conflicting requirementh compromises maust be sought, however, the compromise must be in favor of the item it was desined to protect-in this cam food; personnid can wear protective cklhing.

Becci•e of the necessarily high equipment density in many mobile military strutlures. the space -vailable for personnel may be less trbxq what is considered desirable for operator effiwiency. It is, therefore, important to control the environment within the structure to avoid discomfort. fatigue. and other conditions that may cause degradation of human performance.

reqiirments (temperature.

v ni a . n o s ) f r ml t r p b ai n ns ,,fi, dnoise) for military appbcatli aetle by the published the standards ed in are spt U.S. Art xy Human Enlgineering Laboe,• trtes'" and also by MIL-STD-14722b. The ps V-ary specificatioa is the required Effective

Temperature (ET). This parnmeter, which is defined in the Glossary, combines the effects of temperature. humidity. and air movement on human thermal sensation into a single quantity. In accordance with current military

design chtena for environmientaiiy cutro1 spaces, the recomaneded El vadue is 81.3*F. and the maximum allowable value is 85eF. (The maximum desired dry-bulb temperature is 9 0 0F.) The effective temperature chart in Fig i -i relates ET to dry-bulb and wet-bulb temperatures and air velocity. Fig. 1-2 illustrates the results of studies at th•e ASHRAE Laboratory on the effect of emironmental conditions on the sensation of comfort. The major conditions regulattd by environ mental control are elaborated briefly in the paragraphs which fovvw. Several design aids. including a description of the psychrometric chart which is commonly used in air-conditioninig practice. are given in the appendices of this handbook. * in dw In o W -0 n .m CM-4. 1I4

I

Downloaded from http://www.everyspec.com

a

S//

444

/

ri do4

vk~tto"

o*So

A-IL

CANAA

La'

Ceg. 47 V4 emE M4? # fv . o

0 It f 100

944,gAY. w 34 ipewd

fS

1766I

F*ume 1-1. Chart for 0emmtniy Effecti,, Ty*r.eW e for Normaly Clothed.

SederitWy

ti*

fAW Uopyripftwvv y A5II#Ar

-;mnmt by pwer

nsr

from ASHRAE Guide and Data Book 1967. 1-2 TEMPERATURE CONTROL Tabe 5-1.) In addition to the umi of elctric combustion heaters. heating is sometimes

The most common form of environmental control is the regulation of temperature. Usually. a thermostat is used to control the addition or removal of heat as may be required to raise o. lower the tempcnrature of

achieved by circulation of a fluid connected to a thermal reservoir as. for exampe. in the circulation of engine coolant through heateiused in personnel compartmcnts of some military vehicles. IUmiled temperaturc contrcl

the environment

Can au

In the type of enclosures considered in this handbook. heat is usually added by the use of electric or combustion heatets. and heat is removed by the use of air conditioner%. Most military air conditioners are in the form of environmental control units which include eectric 1-hatia; elements. so that they ,in be used for healing as well as for %voling purposes (The ,fsifieations of military environrmc al control units are given n Table 3-I. and those of military heater, firc given in

1-2

-

,

-

,an;

with

outside air. this is feasible when the temperature of the outside air is low enough so that the required ten., erature in the enclosure can 1,c obtained with a tolerable rate of ventilation. 1-3 HIJWIXTY CONTROL Humidityj• control is important because of its effects on both personnel and material. High huflikdity ;Cduceý the comfort -f prepsA 3nd causes many materials to corrode and

Downloaded from http://www.everyspec.com

A"* MOVEMUE? on ufteutL(cC

So

-

14

110

iflhe comfort dinfurs~Aon curt show that ade nwxkmtmn pmeeneW of poo~p* &#ow4be womlorftbs at 71 ET in maamw at 60 ET mnwi~nm Thm diuribtivacomw are b"O On~ Abe rMMOM Of P~WWM kn, wd&O4' aft., en a condiNomd lpmTO* AW haws VAms 3. 4. 5. mid 6) sOmw tho mcomm of v*.cem aftar &Aeximawgyhkwq how Oc*Spmiwy. If itel a AI m rM ~l~ that OWSM will Ifel quit worm afitt wMiea toan? eftomvn at 85 ET the mmxinim uW~ien on m""ur t^WOic Im

Firpm 1-2 Rei~f ASHRAE Comfort Chiwt Copyriftu by ASHRAE. RO"~m bY Puruvon frogi ASHRAE G"id aW D~a Book 1967.

Downloaded from http://www.everyspec.com

Selectricity

decompose. Low humidity maty cause difticulties in using certain materials. such as paper and fabrics. The increase of static assciated with low humidity may even initiate explosions in sonm environments. amount of moistur' in an en The atmospher dependonmseveral factors.the re depends on sevorai factorus the atmos f moisture content of outside air • ventilation, the amount of moisture that may be added or removed by the environmenta control equipment. moisture that may be added or removed by processes crried out in the enckloue, and on inoisture derived from human respiration and perspiration. When 3i; hokld the maximum possible amount of moisture in vapor form it is said to be saturated. Relative humidity (RH) refers to the actual moisture content of the air, e;ipremstd as a percentage of the maximum amount it can hold at a giWen temperature and preuure. The dew point is the temperature at which air with a given moisture cor, rnt becomes saturated, i.e., the temperature at whch its RH is 100 percent. Fig, 1-2 should be consulted for the effect of relative humidi-

ty on the comfort of penrsonl The controls of temperature and humidity are intimately related because the saturation vapor pressure of water rises with increasing temperature. Therefore, when the temperature of a given atmosphere is increased without the addition of moisture, the relative humkiity decreases. The principal means of relative humidity are to spray the air raisi with water or to evaporate water into it. Relative humidity can be lowered by chemical means, though this is not an economical method. More commonly, relative humidity is lowered by decreasing the temperature of the air to be dehumidified to the dew point of air having a moisture content such that mixture with room air or. in extreme cases. subsequent heated air brirg the proce'sed air to the desired temperature and humidity. Dehumidification occurs when air is cooled in an air conditioner if the temperature of the humid air fait- below the dew point. causing I-4

some of the water vapor to condense. When moist air passew over cooling coils. thete is insible cooling of both the (dry) air and the water vapor, and dehumidification occurs when the temperature of the moist air falls below the dew point. Most cooling coils provide simultaneotsly both sensible cooling and dehumidification. In such a system. the amount of dehumidification which occurs is dependent on the %ensiblecooling load; and it may not necessarily meet the humidity tequirement of the enclosed space. If not enough moisture is removed, the refrigeration system may have to be combined with a sption 4ystem. or. if too much moisture is removed. a humidifying system may have to be added Unlike what happens when mist air n, cooled. then. is no change in moisture content when moist air is heated - though generally the relative humidity is decreased.

Printing operations' provide an example of an application in which humidity control is important. Adsorption and desorption of

moisture can cause paper stocks to stretch or shrink; and when these occur mm-urnifotmly. the paper may become distorted. The enhanced development of static electricity in an atmosphere of low relative humidity -may interfere with printing operation: on the other hand. high relative humidity can prevent proper ink drying. Depending on the type of printing done and the natural environment of the printing plant. separate control of humidtty and temperature may be required. Computer installations are another example of facilities in which humidity control may be important- Lack of adequate moisture in the atmosphere can 'nterfere with the reeling of nagnetic tapes in computer machinery. 14 VENTILATMIO The purpose of ventilation is to renew part of the air in the controlled space to replenish oxygen and to dilute pollutants such as CO0. obnoxiou* funtes, and odor

Downloaded from http://www.everyspec.com

Venttiation and circulation rcquirements

typically contain tarboa monoe•,r. oxides of

for imltar) apphl.atonm arc spe~cfied by H[L Standards. I-or communications systems and related eqwpment. for example. they awe giwen asW

nitrogen. and annmonia arr one source of noxious substasices encountered ini military operations. Another source is the exhaust

"-1 Ventilation facilities should prowide a minimum supply of 1000 ftK of fresh air per person per hour. "2 Air circulation around the operator should be less than 100 ft per min and velocities less than 65 ft per nun are desirablc.

"'S. Hot or cold torced-atr systems should be designed so that the hot or told air discharge !s not directed on personnel." Where odors and furtles must be diluted, the needed level of ventilation can be considerably higher than is indicated in Item I. When the temperature of t!- circulated outside air must be increased or decreased to ment temperature requirements, vrentilation represents maadditional load on the environmental control system. In cases where the heat which has to be removed from a space is generated inside the space a certain amount of air cooling can be achieved by ventiltion with outside air provided it is rot too hot or

products of cniges'b

The maximum &Ilow-

able concentrations of these gases and other pollutants Ifvapors. fumes. dusts, ett i can be obtained from the Threshold Lanut Values published by the American (onfetence of Government Industrial Hygienists. Maximum allowable concentrations of carbon monoxide are gven in I able H.f. Appendix B. The removal of gases. vapors. odors. and tine mists depeinds vet) much on their naturv an6 concentration. If the solubility properties perrmt it. washing or scrubbing is indicated. Other forms of removal are chemica reaction. combustion. and adsorption on an activated solid substatwe suh as sihca gel and activated carbon. or alumina. Provision is usually srade for the rm.onstitution of adsorbent niatenals. usually bý heating. Pa•riculate matter v, th sizes dewn to i imcron in diameter such as industrial dusts. pollen. and bacteria--can be effectively removed from the air with common air filters. ISee Ref. 3. Ch II, Fig. I Spe.:ial high efficiency filters made of dass. or glass-asbstes. fibers-- are uc-essary for smaller-sized particulates' CBR* air filters tied by the military remove 99.97 percent of rlticulatc matter down to 0.3 nmcron in diameter

humid.

Recovery of recr.d.ulated air. as b) charcoal filtration, can significantly reduce the tequired outside air ventilation rates, producing substantial cost savings p-3 illustrates a uail mounting on a transportable hut in which the unit protrudes through the wall mhen in tue. but can be withdrawn into a recessed pos•tion during transit when the un;: is not ,eeded 24 INTERIOR-EXTERIOR A sligh; reduction in tP' requtred cooling capacity and blower power of air conditioners can be achieved by mounting the condenser section extenally and the evaporator section in the wall or. better. inside of the controlled 2-1

Downloaded from http://www.everyspec.com

(Al

Heater mntkiled in poilabk phowop.phc dark room iva (see

Arrowl

(B)

Hleaetr insWul6an in mnbile ground ,tajn comtnrction van

(WYiACru*WAtinj

(C0

hwwu u#mtsw in dwthelt Showing exsut 0w y

pgfdov fe Sri//

Figure 2-1. Three Fioor-mcnted Instollations of 15,000 Brulhr Heatrer

Figure 2-2. Two 60,000 BwuAh Heaters Moumnted Irarde Fcpwwsibe van

Downloaded from http://www.everyspec.com

t|

(A)

Unit in opemi*ng positton

(8)

Urqt in trarsit p•ovon

Figure2-3. 9,000 Btu/hr Air ConditionerMounted Through Wall of Air Trwsoable :u (A special frame allows it to be rolled into recessed position during transir. space. However. the prime advantage of intenor-exterior mounting is greater installation iersatility as described in par. 2-4.2 2-4.1 SINGLE-PACKAGE Refer to par. 2-3. =ir, 2-4 illustrates this type . instalh!in -n the cas of a laboratory darkroom var

Figure24. 9.000 Bru/fr Air Condition-€ Mounted Through Van Wall With Half Inside and Half Outside the Van

2-4.2 MULTI-PACKAGE Greater installation %ersatiht) is provided by environmental control units built with separable sections. Some units have separate condenser and evaporator sctions. and one (18.000 Btu/hr! unit is constructed in five sections comprcsor, condenser. condenser fan. evaporator, and evaporator fan- The sections can be scparatcd and placed in man) "different configurations. mxking the unit compatible -with a vanect% of structures. Fig.. -5 illustrates different t rk-s of installation possible with units having scparac ciaporator aano condensr sections. Fap, >-5 and 2-1 illustrate sone of the installations possible with the five-section unit. A multt-package air conditioner is recoieaended for structures where large mounting holes would weaken the wall. When the evaporator -n. a mounted in the conditioned spac. and the condenser on the outidc. the oDii wall opcning r-qurred is a >- to --m. dianmetcr hole foT passage of refrigerant and elcctnrc lincx 2-3

Downloaded from http://www.everyspec.com

4I FA

Feque 2.5. FreqwJnflI Used Contpra"tion tol Mounting 18,000J Stu/?hr, A(,dd-pwcke Air C*,ndhtionw 2-4

Downloaded from http://www.everyspec.com

each carn/n a fcwtiop cl the la'd. An advantage of this type of instation is that failure of one art: *oes not diaiulc the entire

"V•,'l; as Iog as at leg one unit emauins operable, the "ystem can meet a poriton of the ± A comparable single-unit iutallation

would resut in co.pTI&L- !huY4-nr

Sin

"-

3t

-

R

•e

1 u

of

ailure. Fo& appfhctions in which a disruption full erice is intolerable, a multipte-unit installation should be used with one or more units as standby in case of failure of an operating unit. Multiple-unit installations may also be applied to systems which encounter lawge variations in load requirements depeneling on the season, geographical location, or operating conditions. Occasionally, special consideations incate the use of a multiple-unit instaUaion. For example, the conventional 18.000 Btu,'hr ""envuonental control unit (Table 3-1I. weighs more than two of the conventional

9000 DtuI'hr units Therefore, in this case a two-unit installation would nave the advantage of weighing less than a sinile-unit installation. SITo • ,

••

.

avoid excessive power s$rs in inultaple-unit installations, provision shoud be time delay between the starting of ~individlmade for aunits.

Rk.

Fipure 2-6 fIkhjsratiomof Tha ,ooitr ConfJowbm of 18,000 BtuStr Multi.tckcage Air Corditiow 2- MULTiPLE-UNIT When the heating or cooling load is substantial, and especiaBy if the load is variable, it nay be advisable to we two or more units.

"A practcal examnple of a ta-w.nut ippiication to a sheter is given in fSeL 1.. the thermostat of one a- conditioner was set at the desied temperl um kvel. and the thermostat of the second unit was set about V F above the dered tempeatwe. This made ont unit operate full time while the second unit cycled on oly un-d extreme conditions. Lt.. when the tenipertue was too high for the feist unit to handle the toed. With this nrgement there was little dmaner that both umt would start imultarous•. causing a lar po•we drain on the gnerator. As indicated in a preceding pararaph. unkls th, is a -"cal wamnpanent as just described. multiunits would have to be turned on in sequence to prevent an excesive power surge when starting the system. 2-5

Downloaded from http://www.everyspec.com

24 RyM

•

Remote environnental contrW u

moy

In some appfictons it mkv be advantsagous or ev"• nww to mout the

be mounted on srad traiers or an W•eso skid& Type arrangments wre shown in FOqDI

space being conba&. Rcame mounting is OeniEw Jf I! WOOMture is not strong enough

for ask flow between the enyvnmnental tow trol unit and the controled encosure. Re-

to support the unit as, for ewsanvi, in the

mote-control pael connected to the umi by

cae of an inflatable shdter. A uqwantety-

cable permit operation to be controled from

eswonmmatal coMrul unit remote from the

Sunit

s p •m ."Ml

a

nd

wpeeds installation for riwl-rected stuctures. Econonasa af realized if a seperatelymounted unit can service sreeral structures Which do not require l-time opMtioM. Remote mounting also makes more spece avaiable for other uses within the controlled

2-7 and 2-& Usmally, flexible ducts are eed

witta the endoure. Heat trans•r throuh ft walls of the ducts inacases the requied heating or coolg capacity of the unit, and friction omes through the ducts im the blowr power required for a given flow rtme. To minimize both effects the ducts should be insulated, and they should be kept as Ohort

nd asstraight as possble.

strucure.

"T

!

Fioure -7. iMaltivnof 9.00 Outsid an l-ff•W Stmh

w#f*r A* Comndrw Moun

Entowiny Fmxibe Ducts for Air Flow

Downloaded from http://www.everyspec.com

AMCP 706-120

'JIJ

2-7

Downloaded from http://www.everyspec.com

IAK I

AM~?11120

REFERENCE

1. W. MI. Imlen. Ret

I's

Shefte,

4,,wi1~naw

Icchima4 Rortiv

RAD(-Mr-04-30P.

r f' wphitPlai"

Rqxwrt No. Atr i)cvcdop-

mcm (nciawn. (Anffrj,,, An I--ore ix c Nacw i York. Auwi~ IM96 f AD~sx 7 SOU

Downloaded from http://www.everyspec.com

CHAPTER 3

TYPES OF MILITARY AIR CONDITIONERS

3-1 INTRODUCTION

Ref. 8 lists the units in Table 3-2 for tuture development

The military air conditioners of interest tot applications covered by this handbook have cooling capacities between 6000 and 60,000 Btufhr. They are listed in Table 3-1 which gives some performance and physical data for military environmental control units*. More detailed information on the configuration of these units can be obtained from Ref. 1 which has draisingp of exterior views of the units. The design and testing of some of the compact. horizontal units are discussed in Refs. 2. 3, and 4. It may be noted that all of the compvact units and many of the cninennorta units arc capable of heating -- by means of electric heating elements - in addition to cooling. Environmental control units intended for future developmnent, probably aftet 1970. are listed in Table 3-2.

3-2 SINGLE- AND MULTI-PACKAGE UNITS

In addition to the Carnlcs Iofnemm tal a control units.whichfames ofisted in Table 3-many control un'it. which ate listed in Table 3-.

Environmental control units arc avawlbic in both single- and multi-package configurations. As the terms unpl). the singe-package .,nits are completely self-contained in a unglc cawas and the multi-package units are separable into two or more components wiuch :an bv mounted in a variety of configurations Ihc simplest multi-package units am- those -Ai%.h have separate evaporator and condenser -.tions. such as those shown in Fig. 3-1. Tic two sections are connected b. electnijl cables and flexible. quick-disconnect. precharged refrigerant lins.- A more complex multi-package configu& tion. shown in Fig. 3-2, has five separable sections in addition to the condrnser and evaporator, the condenser fan. evaporator fan. and compressor ane mounted in separable sections. Multipackage units with separable sections arc iN.o discussed in par. 2-4. Single-package units have the advantage oi being morne compact and hghtnr than multipackag units of eual capacit' and corpwabk design. As illustrated in Figs, 2-5 and 2-6. multi-package units have the advanit; of greater instalhtion %vrsatility Other advattt:Ages of the multi-package configuration include the reduction of inventory investment made possible by the fact that ont- unit tits applications and the rapid repair attainable by simple replacement of defectis sec-

OU•bmw DWmi O

tions 3-3 CONFIGURATION (HORIZONTAL

Whecevr possible, the stanAad units Listed in Table 31 should be used in designing air-conditioning systems. Units of 6000, 9000. and 18,000 Btu/h cooling capacity are those used most often ? loads are usually met by installing multiples of the smaller units. Specaai units can be developed for unusual applications only if sufficient lead time is available. Occasionally, it is necessary to use commercial units for these special applications,

bustb t ok#W, MA o at viW. MmilWk Iby Ow FeduaI Swck Rumbae,Me avik

fW P4MUM11•es,, Acm

UThe

AND VERTICAL) availability of air conditioners in both 3-1

I

Downloaded from http://www.everyspec.com

!

t,

""q4.

4

4q

Mill::lii Ili~lIi M!f

I

PUM

" ,:,,'"---.. ,,,,,,,,,,* ,,,,,,,,,,,:- .-$

Its

Atllli t

ill -- zI

•

44

:W049

--

li

l

I

'-4i)

I

Downloaded from http://www.everyspec.com

~VINT-tNlIa

AMU

i

EVAPMaATOR

CONDOENS IA)

MOWd 4/f

wirOrWe~a air ccvndidocvv

Fiqwe34. Exampfe of Air Conditionrw With Separae Condenser and Emporator Seaions (6,0061 Otu/hr Vulti-packaW Air Conditiower

AM

Downloaded from http://www.everyspec.com

horizontal and vertical configurations facilitates fitting the units to the available space. The horizontal configuration is suited pnmarily to window and wall mounting, and the vertical configpAration is suited prim•aiy to floor mounting. Air flow paths for typical horizontal and vertical single-package units

EVAPOAT1O

1

are shown in FiLL 3-3. COMMiSEM FAN TAKLE 3-2 FUTURE ENWROUMEUTAL CONTROL UNITS

(1) Thermoelectric Eni:rwonmental Control Unit. 00060Oanc4IP400 Hz 24,000 Stu/hr, 208-V. 3-phas, S2) Waste Heat Powered Entironmental Control Un01. 60.000 Btufhr (3) Mobile Utdit" Moduies. 18.000; 36,000; 60.000 Btu/hr (Cooling) The modules will provide cooling, heating, and auxiliary electrk power. "They will provide also for inclusion of hot water heating .-d prexurized air equipment when these are specifically required. (4) CompactMultion Air Condftioner. 10-15 ton (120.000- 180.000 Btulhr). 208-V, 3-plase. 60 Hz

3-4 CONTiU ME•ATION

AND INTERMITTENT

c0*9SSG

Multi-ack Figure 3.2. 18,0W Bru 'hr gte3..1,08r hMut-ac• Air Conditioner ori w m t ei ni in contnuois operation. (ontrol s)stenis inmo.!in, internuttent operation are uimpler tnd cheaper than modulating system, hut in many military app#;cztbons. the pouev )urm, ' that occur whtn motors ae turned, on or off cannot be tolerated in other equipment sharing the same power suppW. In such cases one must select unitt, provided with modulating control One method of modulating control used in air conditioners is automatic cyclnmg of rcfngerant alternately through the evaporator sod and a bypass, depending on %tether or not cooling is required. This actucvs contro! of discharge air temperature while allowing th< compressor. condenser and evaporator motors to opetate continuousl). Another method of modulating control is to vary the rate of an flow by means of a variable speed fan or adjust3bk dampers.

To keep the environmental conditions in the controlled space within the desired litnits. operation of the air-conditioning equipment may be controlled by either o V4Oii•ethods. One method involves the intermittent operation of a corrlonent, such as a compressor or a fan, so that refrigerant flow ot the flow of air across cooling -.,;, respectively, is turned on or off. The rmethod of modulating control involves varying the rate of flow of refrigerant

3-4

Control systems having continuous fan operation. with internmttent cooling. tnvole a humidity effect which may not be acceptable i some applicstions. When the cooling cods are cycled off. the continued fan operation causes recvaporation of water from the cooling coils and the drain pan. resulting in lhghe powe, *A"vw0%d

.•

nt,

,- ra,t' -, , dwad

Downloaded from http://www.everyspec.com

EVAP•RATOR SECTION

COLLECTIVE PIOTECTOR MiET IWHEN ATYACHE1o

OUTSIDE VENTILATION Aill

RETURN (ROOM) AIR

WHEN REQUIREO)

I'l

60.000 tu ',hr a,ood•ttoner

COND•ENSER

ACONDENSER

COU4OENSMR AIR

FR1ESH All

RETURN AIR901i

(8) 9,000

Btu'hr aw condfti0wv

Figure 3-J. Two Examples of Sinje-pockap&Asr ConJitioner3

Downloaded from http://www.everyspec.com

fimniuityinv the occupied space. Unless the ,idity can be tolerated, continuous h•,'!e. should not be used. ,-,•iti'n )I r3 : L3 L•CYRIC-POWERFD AND GASOLINEFNGIN*E.DRIVEN nmij:itary air conditioners are designed K, •, ';I operation when connected with lpply indicated in TFable 3-! The wh!w•-, aii conditioners are also designed to

stallation can be mounted on skids or trailers, as illustrated in Fig. 2-8. These portable mountings lend considerable flexibility to installation, and they also facilitate the handling and transportation of the controlled enclosures. The choice between skid and trailer mounting depends on the service required.

Skid-mowited units can be placed directly on the ground, but it is preferable to provide a base to prevent trouble due to snow, rain water, and other deleterious conditions on the

power supplied by military

ground. It is necessary to provide for the

ý'i•,t•~t(os. When system power is limited or requires an air conditioner t)•. •;l•c:•tionl

loading and unloading of skid-mounted unit-

w)t.iitt

fiont

o)LfltL.J (,,

a trailer or skid mounted, a

,0) 00O lBtoi hr gasoline-engine-driven unit is m-.liklbl.. At the present time, only a special, 60,0OO-MB/tur air condi-tioner is available as a ga~olinc-cngme-driven unit. 3-6 SKID- AND TRAILER-MOUNTED Air conditioners intended for exterior in-

onto and from Trailer-mounted

the transporting vehicle. units may be located

wherever room is available, consistent with power and ductwork requirements; and they are easily relocated when necessary. With trailer mounting it is usually possible to provide space on the trailer for auxiliary equipment such as ductwork and collectiveprotection filter units. Hauling a 'trailermounted unit over long distances, especially over rough roads, might be more cumbersome than hauling a skid-mounted unit in a truck.

REFERENCES

I. viditairy Standard (Preliminary), Environmental Control Units, Performance & In,tallation lData, U. S. Army Engineer Rewearch and Development Laboratori',s, Fort Belvoir, Va., Rev. October 1966. 2. Nominal 18,000-Btu/hr Compact. liodzontal Air-Conditioning Units. Tech. Inlobrmation Rep. 33.1.4.2, University of Pittsburgh Research Staff, Wash., D.C., NMarch 1968 (AD-830 057). 3. R. P'eterson. Nominal 36,000-Bltn/hr, Cornpaet, lHorizontal. Air-Conditioning Units,

3-6

Report 1918, Army Mobility Equipment Res. and Dev. Center, Fort Belvoir, Va., Dec. 1967 (AD-665 368). 4. D. P. Swan, Nominal 60,O00-Btu/hr, Compact, Horizontal, Air-Conditioning Units, Report 1932, U. S. Army Mobility Equipment Res. and Dev. Center, Fort Belvoir, Va., August 1968 (AD-676 119). 5. AMCR 701-6, Logistics Responsibilities, Assignment of Environmental Controland RefrigerationEquipment, 4 April 1968.

Downloaded from http://www.everyspec.com

AMCP 701&120

CHAPTER 4 FEATURES OF MILITARY AIR CONDITIONERS

4-1 INTRODUCTION

Ihe puroose of this chapter is to describe

"Yolle of the general features relating to the storage, transportation, installation, operation, and maintenance of military air conditioners. The desilyn objectives of the group of compnact military air conditioners, which cornprises most of the military family, include minimum size and weight, standardization of components, minimum power requirements, and maximum relability and maintainability. The features of compact conditioners include rugged construction; capabilities for automatically controlled heating as well as cooling; for conditioned air delivery against appreciable back pressure; for ventilation with or without cooling or heating; compatibility with collective protection systems; and selfprotection against abnormal temperatures, pressures, anrd loads; and against cutoff of condenser airflow. The hot-gas bypass type of control system is used in the units for precise conditioning without cyclic disturbance of its external Llectric power supply circuit. Par. D-I, Appendix D, taken from Ref. I, specifies the general technical characteristics

required of van-type air conditioners designed for military use. A description of the refrigerant circuit with a hot-gas bypass control system is given in Par, D-2, Appendix D.

tioners which are to be used in military applications wherever possible, and it gives the procedures which apply when special purpose equipment is necessary. General specifications of the units are listed in Table 3-1; information on the featwes of military air conditioners can be obtained from the Military Specifications listed there. Additional information, including the discussion of problems and their correction, can be found in development and testing reports and operating manuals, such as Refs. I and 3 through 11. (2) Ref. 12 describes the environmental conditions, including climatic doign criteria. that are to be considered in the design. development, and testing of materiel by the Department of the Army. Environmental requirements for materiel of the Mobility Equipment Research and Development Center (MERDC) are clarified in Ref. 13. (3) Ref. 14 includes specifications of some of the tests used for determining the resistance of equipment to environments peculiar to military operations - such as temperature. humidity, fungus, salt fog. and vibration. Ref. 15 gives the MERDC vibratior. .. st procedure for air conditioners. 4-2 SERVICE VERSATILITY 4-2.1 COOLING CAPACITY

Althougn the air-conditioner features are amplitied in this chapter, one must reter to other documents for more detailed information. Some pertinent references are:

The full rated cooling capacity must be delivered at ambient temperatures up to I120°F, with the return air having a dry-bulb temperature of 90rF and a wet-bulb temper. 0 w bnt yte aly aas shown ature ature of of750F. 9FUsually. by the

I I) Ref. 2 lists the family of air condi-

example in Table 4-1. the sensible cooling capacity is specified as a percent of the total 4-i

Downloaded from http://www.everyspec.com

TABLE 4-1 COOLING CAPACITY SPIECIFICATION FOR 60.0%) BTUIHR VERTICAL. COMPACT AIR CONDITION'ER (ram #Miwaiy SpscfAlioa MIL.A-U2S15MO)) Ev

,aeAhAnt

Ammnst rPma~tar.

F Dofw rY Seab

Dry Bull)

*a BUtt

SmuI.k Cco-" Total so ,w

of TC Tot. mnesC001i" cc"city. %Sti

CASiemvt

A

120

9

75

6u

60000

C

95

80

67

65

60.000

.oolng capa,.at) tor ,_ifferent ambient and return conditions,

hercnt to ihýs ollecinc protectiton syý-tem 1o be compatible with collective protection. air-

condit;

-z units

ha~t the

4-2.2 HEATIr•G CAPABILITY All of the compact units and some of the conventional units have thermostatically controlled eiectncal heating capability in addition vo the cooling capability. On some units. an clectral interlock prevents operation of t-ne heaters dunng cooling,

II There must be neglipblc ir 1akage from the evaporator when under precsure (2) Lsc of a blo--throuah eraporator ?an ari a pull-through condenser fan i, required to help proent leakage trom the oatside to the conditioned --ide If the ddpp I 11 -n a coliCtJre protector vs exposed lo the

outside air. it must be prssunrzed to asoid

4-2.3 VENTILATION

recontamination of the suppl) air When cooling or dehumidification are not required. %entilation can be obt,:. •J b-. opening the fresh air inlet damper andperating the evaporator fan alone. Whti .ooling is required. fresh air can be introduced as desired by adjusting the ilet dam-per

4-2.4 COLLECTIVE PAW ULITY

PROTECTION

C'-ý'-

For installations requiring prot.tiors again•t chemicaJ. biological, and radioactive contamination. unuts are provided with a separate inlet for connection to a collective protector filter unit An auxiliary evaporator air blower may be required to overcome the statiR pressure loss and ductwork loss., in-

4-2

03 Travs and check salfs the Lo.,densjlc drain%

are required in

141 Head presure .on'trol is requ.n-d it', permit op-rat.on on %.oohn! in io- ambient temperature Cooling ma% be req-ired ever with lo% ambient temr.erature if the internal heat generaton i% high enoriuh Accordingy. the hiead premurc Lontro! %s~icmri designed tit flood part of the condenser and maintain condenser pressure when the ambient temTerature drop, .x) lov. that the pressure differetti d,,rkr, th0 esaporator expansion valve bcrt-)ome, ton small to induce the floA of refnrerant needed to sauisf. the load

Downloaded from http://www.everyspec.com

411-2.6 COMPATISILITY WITH SENSITIVE ELECTRONIC SYSTEMS Electromagnetic radiation ciranae±iaS from eictromitchaical equipment can interfere wth~ zhe operaton of sensitne electronic equipment. Such tnterference can result, for ey~mple, from the current surges generated when motoi-s start and stop. Features which reduce such interference arm (1) Use of a hot Sas bypass for tempersture control eliminates the stopping and restarting of the compressor aftez the Ifintial itart. thereby preventing current surges. This systei , is described in Appendix D)-2. (2) Use of a pressure equalizing, valve and electrical control of the starting sequence of fan and compressor motors minimizes cutint surges during the initial. manually-actuated start(F control devices such as main power line andsheddcb.

7

THE PCW&R SUPPLY

put most units into op.-lawan, it shouEJ suffice to connect them to drain lines icondernwte lines in the c.oolinS mode) and the proper electrical power soure. A siraple. readily accessibit selector switch should allow the opefator to select easily the heating. ventilating, or cooling mode of operation. In the cooling or heating mode, the enclkiair tempvrature should be aulon~xically controlledi by an adjustable thenmottat. Simple damper adjustment should permit control of the amount of fresh air entering the enclosure. The use of principles of human engineerin, in the de-sig of the controls makes them easier to use. Standardizvt.n o1 controis permits personnel familiar with the operation of one unit to opmstc other units in the saunie famnily without !idditional training. t

ho aigtmet ihsc Safety and ease of operation are enha~mcd by providing moving pans and parts SUbjeCC guards if they present a hazard to per-sonnel

of the compressor. when units are itrutil1

su.pply. Typical requiremnents call fo~r 60 cps

ratcd frtquencv at voltages between 95 and 10 pei%..nt of the rated value.

4-3 EASE OF OPERATION Miiayair cuaditionern are &csignd fo maximum practicable eaw of operation. To

PWL tm eitim*Rma (MM the rthn MuEIt gew i sbhdied "~ a tWkA-of puate

O't

Caeol abn muz* bt #dtUd of ther4M =*- t

performance and communication of personnei in the conditioned ý.pacc. Quiet operation is needed for intelligible conversaton 41~tna voice levels and for satisfactory ese of telephone and open microphone-peaker systemns. In sorme cases-. e2l!temall sound attenu~to- airr needed to satisfy the noise requiremcnt,-

The inobiltay of in'itary air-conditioner' it. enhanced by design &catureswhich lower the 4.3

Downloaded from http://www.everyspec.com

size and weight of the units, by arra

nnnts

which yield high rcstiance to shock and vibration. and by provumon of lifting and tie-dowa devices. Canvas covets can be prov•ded to prooect the condenser side of the units during transit. Canvas covers should also be provided for the evaporator sections of ,kid-mounted units during transit.

I I Self protection

tn} Ovcrtemperature element

cutoff for hter

(b) O(erpressure cutoff for compressr and overpressure refrigerant release device (c) Antifrost control for evaporator coil

The accelerations and vibrations which envirc rimental costrol units am required to

(d) Automatic

cutoff when ambient

dr-•. -_ ibelw

db•!a-- . n,--

-mthstund ca-tbe toutd in the Military Specti fications refernced in Table 3-1. which also lists the size and weight of the units. Corm-

mum

pliance with the specifications isurwes tt the units are capable of withstanding loads associated with transport over rough terrain with-

(t) Ohvrcurrent and winding overheat cutoffs for motors (To avoid needless tnpping of circuit breakm used in cutoff circuis. a

out ecqwung pump-down+ and blocking or te-uown of internal components.

tone delay dependent on the magnitude and duration of the current overload is employed.)

4-5 RELIABILITY AND DURABILITY

(f) Phase sequence reina

for 3-phase

units The reliability cbjectvts for mditary air conditioners are MI, Missuon reiabmhty* of 95 percent with Simission timr ,), N4 hr (21

A

mean-time-between-failures*

of

1 104 hr w;th 0'0per~ent confidence rice life of 10 yr. with 4000h 3) A .oiaerhieouls..wth400h (3tweA

(2) Construction

to withstand salt

rain. misture condensot"on. fungus. inmect attack, dust. sand. and high ambient temperature and humidit. (0

The use of a filter-d•rer irn the refng-

erant circuit to remove mosture. filter

(4) Hermetic compressors

Although the mean-tim- -betwcen-failures is important. it does not suffice to give a total

i15

to Features now avaaiable which contribute the durabilit. and rehabdit' of military air

nm-

purities. and act as an acid neutralizer

between overhauls.

indication of system reliability. Equipment reliability also imolves the case of repair and the simphcatt of pre.entive n 'ntena.ne procedures. These feature, are d&scusscd in par. 4-6.

fog.

Hot gas bypass temperature control

ib A rng sccured to cabinet and electncal totors to present abrasion of insulation C7) L se of high temperature soided joint, ;n the piping to reduce the p.svAbilith of

leakage an the reirigerant ystem IS) Permanent type filters. i .ones which can be cleaned b) washing or brtshing and returned to w-',%-

S4t) S"m

4-4

Tube fin coali pmp4-3.Appe-t•A.

I 10I

;•se of an cectritcal mnterlfck to pre-

Downloaded from http://www.everyspec.com

vent ormtion of the heaters when the ak

for routine Service is less than 5 percent of the

c.aditi,'•r is wt for cooling,

COgkting til

414t 14MI•TENNE

for life so that no routine lubrication is

(4) Motors and compwrwe are lubricated

for military The maintenance requirements airconditione-rs arm given in Table 4-2. Some of the features now available which reqrments and whih p to achieve t facilitate maintenarwe when it is roquied are: (1) Interchangeability of as many components as possible among the environmentai control ums in a family should be the rune. This re,.quirment reduces not only the supply costs for s-pare pam but akso the trainit requirements. Personnel trained to perform naintenance operations on one unit can persorm the ayme function on othc'adnits of the same faly with titl if any additional tramaing

(5) 1nditionm, In some air

the

sor is mounted on a frame which can be slid out like a drawer to facilitate its removal. (6) The cledtncal imucon box is Arranpd to permit removal from the unit to facilitate servicin (7) Major electrical components are connected by MIL-STID connectors to facilitate repem (8) Fixed anchor nuts of the floating. ekin type used to facilitate maintenance and to reduce the number of loose

pans. (2) Access panels are provided to facilitate maintenance. Greater facility is achieved if the filter and maintenance access panels af the mounted on spring hinges which cause doors to close when released

99 The number of different types a A is kept to a minimum.

(3) The permanent type air filters, which

(10) Drawings are furnished for each non-

must be inspected periodically and washed s necessary. are the only items that requie frequent attention. The filter cleaning operanon require !ess than 10 min. The out time

standard military component. including the smiJllest pams. (II) A single refrigerant. R-22. i used in all units in the compact family.

TAKtE 4-2 (021 The refrigerant system includes s.rvice valves to facilitate p-eventrve mamtenaie checking.

MATENIANCE TWA 0oSCTIVES FOR WLIARY AIR COU•TM•IS

O(ar cr

13) A liquid line sight glass ineucates

aMd C* W6waSin

Okme I I I

PIsgini. 1

h

Gome pWL

wehether there is moisture in the reffigerant or a shortage of refrigerant.

h (14) Number coding is used in the wong.

Men-T,,,e-

(15) Lifting handles or attachientu ame Moan-Tim.-

to-Rap.'

4

8

24

provided to faciliate dsnnomaoning %rith safety if trouble shooinjg is required. 4-5

Downloaded from http://www.everyspec.com

(4) Provision is made for the attachment

4-7 lNSTAULLATM

S~of

ducts.

The following are some of the available fatumt which facilitate the imstalation of military air conditioners:

1!) Unts of each cooling capacity are avzilble io vertical and horizontal contfgurations to facilitate accommnodation to the avadable space.

(2) A choce of power soutce type is available.

(3) Mounting is facilitated by lift fitting. tie-dowrs, ard built-in attachment devvs. Captivc nu• are provided in the base and back of the units.

(5) Provision is nmde for remte mounting of the control panel and the thermostat. (6) The stde surfaces of the units are free of air apertures and Maintenance access panch to permit sidc-by-side installation. 48 STORAGE Mihtary environmental control umts must meet the requirements of Ref. 12 got static exposur to salt fog. ra-n. fu-igus and insect attack. and blowing sand and dust without undue deterioration or excessive cleanup are startup time. Environmental control units must also be capable of storage w-ithout damage at ambient temperptures from -65' F to 15MF.

REFERENCES

1. R. B. Sherfy. Nominal 36.000 Bruihr. Conrenitmd. Standard Weigt. SingleS.ection. 208-svit. 3-Phase. 00-cycle (Model CE36HBC6-208i Aw-Conditionsrg Unit. Report 1854. U. S. Army Engineer Research and Development Laboratories. Fort Beihotr. Va.. May i "66 (AD-485 823L). AMCR 701-6. Longttcs Responsibilities. Asugnment of Environmental Control Umits. Including Air Condtioners. Refftcrators. flea irs. Fams. Blowers. and Dehumidifiers. 19 May 1964.

4. R. L little. Air (ondtuvneri v v#'wb Bliuihr, Muln-Package. 1,1,-ioht fVk-cic and 20P!4.-zt'h 400-s ch 4-wirc. Technical Report 1695-TR. U. S. Armn. Engineer Research and Development [aboratories. Fort kivoir. Va_. I Sep ember 1961. (AD-272 179). 5. H. R. Lopez. Engyneenng Report o! TwokSecnon. 36.10,91 Stu hr 4tr-O(nditinning Unit. Technical Report Ioi I -TR. U. S. Army Engineer Research ar : De. velopment Laboratonem Fort BeMo'u. Va.. 23 December 19.59 iAD-232 9031 6.

3. P. E. Chappell. .ominal 9.000 Btuihr. Compact. iertical. 230-rolt. SinglePhase. 60-ticle (Model CE)I VAL6-230i and 208P-motl. 3-Phase. 400-cyclk (Model CElI 'AL4-20P') APt Conditioning Units. Report 1841. U. S. Army Engineer Research and LDevelepment Laboratories. Fort ld-o4r. Va.. December 1%5 fAD-631 325.

4-6

0. Oidbcrg. lEguneer LDksgr Te..t Report of a 9.000 Btu hr Sphll-Mountng. (6nrentional-Ti-pe Aier Conditioner. Reporn 1836. U. S. Arm% Engneer Research and DInevlopment Laboratones. Fort Bihotr. Va.. Novcmber 1%65 (AD-1,." 301 01. Oldberg. [)eeloprnnt ,,tnt it 1IfBtu hr. Gas",lne-L"ngne-DnIer,, Ifultva kagr -itn (•,nditincr. Report I 7%.

Downloaded from http://www.everyspec.com

AMCP 706-120

U. S. Army .nierResiearch anid 1)cvelOPrllunt Laboratorie~s, Fort eldvoir, Va., '28 January 19055 (AI)459 445).

Ii

J7(J9-IR, U.S. Army Engineer Research and Dievelopmnent Laboratories, Fort IBelvoir, Va., 15 March 1962 (AI)-283 204),

8. J. F. Rylleska, lintil Report o! Sf'rvthe It's of 36,000) Bti r,/j 60-cyciv, Single P'ackage, Jiorizontal, ConeflonlI0iel h'pe .,fir Condiltioner. U.S. Armiy Airborne,

Himcronics antl Specjial Wailare Board, Fort Bragg, North ( ablitia, 28 Dec. I 904 (AD-487 491 L).

9., .J.,Smih, Nmine M,01ý itrih, 9 , C.I. :V ppiIial Symjl i6, 00 I i ('/Jr..ýJ

Comnpactl, V'ertical, 208-t'olt, .,-1'ase, 4 t'- vdc' (M/odel (T10) ~'4 L.W) nd 20H-L'olt, Y Phase. 400-vcvch' MAodel CI:40V,4L4) A'ir-ComditioninK Units, Re-

por" 1861, U.S. Army Engineer Research and D)evelopment Laboratories, Foi Belvoir, Va., June 1966 (A[)-638 011),

10. TNI 541 20-295-15, Air ('on dtiP.',pr, Ifloor Mfounting. ,Ifir-( ooled W00, /lJ1ite/ Pr, 20N '/4Pe volts .50/60 cycle'. .- P/mve, Carrier 11ir (and/hloning (Co. Model 76E3.1410.4, 7 November 1906,

11 McDulnakl Und L.H. Adkins, Eng(it crnfg Repori of' 6, 0OO-BLui//r A ir Cot11f TcnclRpr 1-oii

1 2. AR1 74-3K, lWvxurti.lkr,

~

ii': 4 und Luiltiaton of' M¶aterwi for !f'xireppi ( tdhiSMy19.

13. U. S. ,Armiy

M'ý)hility

LII m idj~D evelop mnlL mt

EquItpment RcCenter., /5,: irm i-

me ,ittd I'quiremieni, for MaterielI of fllu' Molr'ijify' Lquipmen''t C(v'untr, Letter of 28 Jall. I 965. Research. D~evelo~pment and l~niti~tccring iDirvcctorate. F-t. Belvoir, Va. 14. MII-SlI)-8101J. Liznmiroinmwnu( I es 31 ,hod&, 15 June 190J7, Notice-I. 20)

Oct. 190)9. 15. Tcý,

l'w~cu/ire' V.\ 1.54 librawiv: t!.S. Armay Mobility Lq uipment Research ano IX'~v~e~pmcn(i ('-iiter. Fort Bekoi,jj Va.. Novvinher .1'47.

4-7/4-H

Downloaded from http://www.everyspec.com

AMCP M130

CI•APTE R 6

TYPES OF MILITARY HEATERS

5-1 INTRODUCTRION

As with air conditioncrs. heaters ý.an be tnstalled in a vanety of wa) s. i.e.. thc• can be

Military, heaivi- consist primarily of elctric. combustion, and automotive types. A brief description follovs

mounted on the floor as shown ui Fig. >-1. and small units can be mounted on shel, spa•ce as shown in Fig. -2. Heaters .an also b< skid-mounted and trailer-mounted.

ti lecrnc lleaters. Heat as generated by passage of current through a resistive element, Most of the electric heaters used in mobile systems employ a blower to draw air over the hot element and discharge the heated air into the space to be heated.

All heaters require electrical power for their operation. even if ori) Ln the control ciucuitrv. In most cases, an external power source as r-qwred. but engine-dnven uits ,an be completely self-contained, with a generator as an internal componerat. Several of the military heaters are listed in I able 5-i Al are combustion hcaters thich require pow'er on)% for auxilar) puroses , as Lonutoi and the operation of electric fans and fuel pump, One of the units dcscnbed in P-r 5-3 11- i 5-') is of this type.

(2) Cw usn !icakrs. Heat is g rted by burning a fuel. which is usually gasoline or a diesel fuel. in heaters designed for mobile systems. A heat exchanger is u, :d to transfer heat to air which is then discharged into the space to be heated. Exhaust gapes are vented separatel) to prevent contamination of the heated air.

5-2 ELECTRIC HEATERS (3) 4utusmone Heaters. Most automotive heaters are designed to make use of waste heat from the engine, air being heated by a heat exchanger through which the engine cotlant flows. Automotive heaters arc designed for use during transit. while most other s;ed during transportation of hea•t" are n the equipe•nnt

in which lhe) are mounted,

Automotive heaters may be used to suppi) heat either to a vehicular component or to the crew cem;a2nmem. The famtiles of military heaters are tisted in Appendix 11 of Ref. i. which gives the logstic responsibilitmm for eritronmental control uits. Technical data and the characteristics of military heaters are liven in a prop-.d Military Standard 2 . A summary of heater specifications in Re(. 2 ts lsd in Table 5-1.

S•

A vane., of requarements ha~c handhcapped efforts tow-ard %tandArdization of separate electric heaters. Heaters expiwted to be available in the near future ha%e relaticl.% small heating capicites. 4nd their chde use is an spu,, hlaur*n L.nits ot 1,gt-r capacit% are expcctcd to be deocloped

Although clctm. heating systems have lowe; overall cconomý than combustion heaters. theq have %scsraladvantages (I ) Dectrc h.-attng is clean. 42) The absence oL cum•justion products ebhrmnates the problem of their disposal and avoids the danger due to toxii. .ses such as carbon monoxidr. 5-1

Downloaded from http://www.everyspec.com

AMCP 706-120

A~

Z.

T z~ x

w

r r.w

cc~~~..

.,-r'


itern in aordance -,4th dc~gn. Fans and rnotor-s sJhoird. thecefume bc Nclected to provide itIm i sli~ht factcor of i~afetv. and darnpc-ý hould be

VELOCITIES FOR CONVENTION4AL SYSTMW (Adsptsd from Re.~ 12, Chepw F

brAnch outictl

InstallIed in cach

TABLE 0-1 EN IAPDMXUMUC

E

-

--

-

--

_______

%~fMw

for Iaian-cing thle systrm

Vetoctaiw. ftirmnn

**b Avo-Ad qbstructing ducts with piping. conduits, or stnt;;tut;Ji ffeflbm

Un-

avoidable duct obsructions musl be strOutdoor~ drop. tht, length of which should bt at least three tin es the thicknews of the

-vai

-

Re*encti 00

Air Intakes

~ ~ a

Some of these rules arr Alustratted in Fig-

Mon Ducts Brach Ow-s

Branchi Risen

dat

rcported': to twse pven satisfactecry rmulls in cot enttonl systerns. mnay provide a guide for siectuig the - elocity of air -.n ducts. Since

prc2ssure low--* increae Approxifnately as the square of the vekx-.ity amW fan noise geneaztion increases With sttxti pressure Vek)ilttes

~

se

Cc;ýc

~

250

350

10001600

16OD-2400

700900 500

1200-1800

Outdoor Au Fotm~ a FnOwtiets170 noeSM Brom- Cum ~ ucs7000 Brarx -00 ;-h~ ~ ~1~

5

800 1000

S00 S00 Maximrum"Vnioccties. t1'imin So 800es 1200 0036 1700-2800 W 1320 700100 1ow02800

9-5.2 DESIGN VELOCITIES

The veo-.itics Wt~ed ir, Table 9-1 . which

500

5

fan Wes

tear-drop."

BuwIchng

0010

100-60 0

~ faaae

itre~tfe

me., other veioctpes irs xabie are lo net free maft

~

C

C~jhftdby ASKRiAE QC

Rteprtrayperrntivon

9iASJAE GuWeold Orta*IOw f~x

V:should

;