Arctic hut heating and ventilation trials

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Arctic hut heating and ventilation trials

NATIONAL RESEARCH COUNCIL

CANADA

DIVISION OF B U I L D I N G RESEARCH

ARCTIC HUT HEATING AND VENTILATION TRIALS

by

A . D, Kent and A. G. Wilson

( A j o i n t p r o j e c t of t h e D i r e c t o r a t e of Engineer Development, DND (Army) and t h e D i v i s i o n of

B u i l d i n g Research, NRC )

Research Paper No. 109 of t h e

D i v i s i o n of B u i l d i n g Research

OTTAWA January 1961

This 9aper d e s c r i b e s and gives t h e r e s u l t s of a compre- hensive study of t h e h e a t i n g and v e n t i l a t i o n of a p r e f a b r i c a t e d Amy a r c t i c h u t c a r r i e d out i n t h e f i e l d during t h e w i n t e r of

1950-51. It i s considerably l o n g e r t h a n t h e u s u a l r e s e a r c h paper

d e s p i t e t h e s u b s t a n t i a l condensa-tion of t h e r e s u l t s tvhicli h a s a l r e a d y been made, and i n a d d i t i o n i s of i n t e r e s t t o a l i m i t e d number" of t h e r e a d e r s of any one s c i e n t i f i c o r t e c h n i c a l journal.

On t h e o t h e r hand it c o n t a i n s mucli valuable information n o t

a v a i l a b l e elsewhere f o r t h o s e i n t e r e s t e d i n t h e p e r f orinance of

camp-type b u i l d i n g s heated w i t h space h e a t e r s , I n view of t h i s t h e

Division has adopted t h e unusual course of i s s u i n g t h i s paper i n

t h e Research Paper s e r i e s even though

it

has not f i r s t been

published elsewhere.

The t r i a l s were i n s t i t u t e d by t h e D i r e c t o r a t e of Engineer Development, Depar%ment of National Defence (Army) a s p a r t of a program o f development of t h e a r c - t i c h u t , and were c a r r i e d o u t

co-operatively witli t h e Division of Building Research. Consequently,

many persons i n botli agencies had a s h a r e i n t h e work and c o n t r i b u t e d d i r e c t l y o r i n d i r e c t l y t o t h e development of t h e i n T o m a t i o n now

made public, Assistance was a l s o given i n t h e a n a l y s i s of f u e l s

by t h e Fuels and Lubricants Laboratory of t h e Division of Mechanical Engineering, NRC, and by t h e Mines Branch, Department of Mines

and Technical Surveys.

The a u t h o r s a r e mechanical engineers and r e s e a r c h o f f i c e r s with t h e Building Services S e c t i o n of t h e Division of

Building Research, Both of them were involved i n t h e planning

and d i r e c t i o n of t h e work throughout t h e p r o j e c t and i n addi-tion,

M r . Kent vias a c t i v e l y engaged i n t h e f i e l d operation.

Ottawa

January 1961

N.

B. Hutcheon,

TABLE OF CONTEXTS

....

...

Introduction

. . . , . . o . . . o .

...

Erection Si'te

Arctic Rut Construction

...

...

Donjek Prototype Hut

Heating and Ventilation Equipment

...

Methods of Test

...

Meteorological Records

...

...

Ehvironmental Records

Ventilation Rate

...

Heat Balance

...

Discussion of Results

....

...

.

Conclusion

...o...

Page

1 2 2

ARCTIC HUT

HEATING AND VENTILATIOlJ TRIALS by

A. D. Kent and A. G. Wilson

I n 1950 t h e D i r e c t o r a t e o f k g i n e e r Development,

Department o f National Defence (Army) completed t h e development

o f t h e Mark

3

v e r s i o n of t h e P r e f a b r i c a t e d Arc-tic Hut, following

which a prototype u n d e ~ v e n t a s e r i e s of t r i a l s t o determine i t s

general s u i t a b i l i t y f o r t r o o p accornrnodation i n t h e Arctic. These

t r i a l s included t r a n s p o r - t a t i o n , assembly and disassembly, occupancy, s t m c % u r e , m a t e r i a l s , and h e a t i n g and v e n t i l a t i o n ,

The Division was p r i v i l e g e d t o a s s i s t t h e D i r e c t o r a t e i n t h e planning, i n s t m i n e n t a t i o n , s u p e r v i s i o n , and a n a l y s i s of records o f t h e h e a t i n g and v e n - t i l a t i o n t r i a l s which were conducted from October 1950 t o A p r i l 1951 a t Donjek River Camp, Yukon

T e r r i t o r j .

The purpose of t h e h e a t i n g and v e n t i l a t i o n t r i a l s was t o t e s t t h e occupied hut under f i e l d o p e r a t i n g c o n d i t i o n s , and

s p e c i f i c a l l y t o determine t h e following f o r d i f f e r e n t degrees o f

s e v e r i t y of-weather conditions and d i f f e r e n t methods of hut v e n t i l a t i o n .

( a ) C o m f o r t c o n d i t i o n s of t h e hut environment a s

c h a r a c t e r i z e d by t h e a i r tenpera%ure

,

r e l a t i v e

hcmidity, s u r f a c e tempera-ture, a i r v e l o c i t y and a i r q u a l i t y .

( b ) Heat i n p u t s and heat l o s s e s o f t h e hut and

i t s contents.

( c ) Performance and adequacy o f t h e h e a t i n g and v e n t i l a t i o n system.

( d ) Probable i n f l u e n c e of %he hut f l o o r heat l o s s e s on permafrost below t h e h u t .

This paper gives a general account o f t h e s e t r i a l s and

t h e r e s u l t s obtained. Item ( d ) w i l l be t h e s u b j e c t o f a

2. THE EREXTION SITE

Donjek River Camp i s a Royal Canadian Xngineersf road maintenance camp l o c a t e d on t h e wooded southwest slope of a mountain overlooking t h e Don jek River b a s i n a t Mile ll3O on t h e Northwest Higbivay System, 214 miles northwest o f Whitehorse,

Yukon T e r r i t o r y , The hut- was e r e c t e d a t t h e south end o f t h e camp w i t h n o r t h e a s t

-

sou-bhrvest or'rentat.ion f a c i n g a l a r g e c l e a r i n g t o t h e s o u t h e a s t (Pig. 1 ) - The n e a r e s t a d j a c e n t h u t was s i t u a i x d 25 t o 30 f t t o t h e nori:h~vest; t h e r e was

v i r t u a l l y no shading f r o m t h e sun by nearby t r e e s ,

The ground a t t h e e r e c t i o n s i t e o f -the h u t consis-bed

o f loose sandy s i l t t o a depth of approximately

6

i n , , w i t h

permafrost below. There was no g r a s s o r o t h e r gro'md cover below t h e hu3.

3,

ARCTIC

-

HUT

COlTSTRUCTION

The a r c t i c h u t

(Mk.

3 ) i s a p r e f a b r i c a k d rec-bangular f l a t r o o f s t m c t ~ x e c o n s i s t i n g of a b a s i c lmit 44 f t long by -

18 f t wide and 8 f t h i g h t o which a r e appended -mo s t o r m

porches, one a t e i t h e r end entrance. The h u t i s designed t o be e r e c t e d d i r e c - t l y on t h e ground w i t h no f i x e d fomda+' sons but uses bearing pads on t h e underside of f l o o r beams, shaped

t o s u i t t h e contours o f t h e ground. Vialls, r o o f , and f l o o r

o f t h e strr~-ctuxe a r e o f p r e f a b r i c a t e d 2 1 j ~ ~ o o d panel c o n s t r u c t i o n ,

supported by aluminna e x t r u s i o n r o o f g i r d e r s and f l o o r beams, and f a s t e n e d t o g e t h e r by s p e c i a l connec%ors f o r easy and r a p i d assembly, ' Panels cont-skiing xindovis a r e in-be:cchangeable w i t h

standard w a l l panels t o give f l e x i b i l i t y i n a~mangeneat of natval 1-ighting, Non-loadbearing par-i-i-bion p a i ~ e l s can be i n - corporated f o r v e r s a t i l i t y o f in-kerior room l a y o u t ,

A

s p e c i a l roof panel i s designed t o accoxmodete ' ~ 3 e _{roof v e n t o r "jack",}

which provides an o ~ . t i e t T o r both the h e a t e r f l u e gases and v e n t i l a t i o n a i l , this s 2 e c i a l panel being inixrchangeable vii-Lh any standard r o o f panel, f o r P l e x i b i l i - t y i n h e a t e r locatioi?,

Wall panels a r e approximately 8 by 4

ft

5y 3-1/8 i n , , c o n s i s t i n g o f i n t e r i o r and ex-Lerior shee3is of 1/4 i n , e x t e r i o r grade plywood glued. and n a i l e d t o a 2 5/8-in. v~ood frame*~fork, t h e i n t e r i o r s h e e t having a pain-kd v a p o 7 ~ r b a r r i e r on t h e non- exposed f a c e , Irzsula-ticn i n t h e panels i s 2 5/8-in. o f g l a s s w o o l e The edges o f ec?.ch pallel a r e P i t t e d w i t h an al~?sni:~~m. s p l i n e

s p l i n e r e c e s s , each m i n g -Yne f u l l l e n g t h o f t h e p a n e l , t h e l a t t e r f i t t e d w i t h a

1 / 4 - i c ,

rubber s t r i p bonded t o t h e aluminum.

The upper h a l f of each windova panel i s framed t o

accomrodate t w o ii~indo'~1: openlilgs

.

The lower opening con-Lains two f i x e d wilidorr~s each 32 i n , l o a g by 12 i n , high, equipped w i t h t h r e e slieets o f c l e a r c e l l u l o s e a c e t a t e p l a s t i c , and

an

e x t e r i o r s t o r m s a s h w i t h s h e e t s of v i n y l c h l o r i d e ace-tate r e s i n

two s h e e t s of p l a s t i c i n a transom s a s h hinged a t t h e lufrer edge t o open inwards, and an e x t e r i o r removable storm s a s h w i t h

sing12 p l a s t i c s h e e t . The storrfi s a s h f o r t h e upper window

c o n t a i n s e i g h t 1 - i n . diameter h o l e s w i t h a wooden cover

p i v o t t e d a t one end and equipped w i t h a s p r i n g s t e e l c l o s u r e ,

The f l o o r p a n e l s a r e approximately

9

by

4

f t by

3 3/8 i n . and a r e s i m i l a r t o t h e w a l l p a n e l s i n g e n e r a l

construc-Lion and i n s u l a t i o n except t h a t t h e 1/4 - i n . i n t e r i o r

plywood f a c e i s r e p l a c e d by a 1/2-in. composite board c o n s i s t i n g

of 1/4-in. plyvood w i t h 1 / 8 - i n , hardboard f a c e s on e i t h e r s i d e .

Roof p a n e l s a r e a p p - o x i n a t s l y 1 0 by 4 f t by 3 3/16 i n . ;

t h e i r g e n e r a l c o n s t r u c t i o n i s s i z i l a r t o t h a t of t h e vrall p a n e l s

except t h a t 5/16-in. ply-~~ood i s used i n place of 1/4-in. on

t h e e x t e r i o r f a c e of t h e p a n e l , Palen assembled, t h e roof p a n e l s

l e a v e a 9-iu. overliang a l o n g tile s i d e s of t h e liut.

DONJEK PROTOTYEE RUT

Figure 2 i s a n i n t e r i o i - view of t h e b a r r a c k p o r t i o n of

t h e h u t d u r i n g occupancy. Tne 3- b y 3 - i n , wooden p o s t s v i s i b l e i n

t h e photograpli mere i n s t a l l e d t o s e r v e a s thermocouple s u p p o r t s . The i n t e r i o r arrangement of t h e p r o t o t y p e h u t e r e c t e d a t t h e

Dorijelr s i t e i s sho~vn i n Fig,

3 ,

It was d i v i d e d i n t o -two sec-tions.

The l a r g e r s e c t i o n , c o n s t i t u . t i n g approximately t h r e e - q u a d e r s

of t h e h u t , was arranged t o accorn~~~odat-e twelve men; t h e remainder

served a s a n instl-unen-b room and s l e e p i n g q u a r t e r s f o r t h e two lion-corninissioned o f f i c e r s i n charge of t h e t r i a l s .

Lavatory, shosirer and t o i l e t f a c i l i t i e s a l o n g w i t h laundry equipment were i n a s p e c i a l h u t e l s e v h e r e i n t h e camp, E l e c t r i c a l pol/ye_r was s u p p l i e d a t 50 c y c l e s , s i n g l e phase,

110 t o 220 v o l t s by -tlie camp d i e s e l - d r i v e n g e n e r a t o r .

5. HEATING AND TJE2TTILATIOTT %WIR!IEN'P

Heating was provided by a s i n g l e o i l - f i r e d "pot-typef' space h e a t e r with a domeskic c i r c u l a t o r cabine-t l o c a t e d a p p r o x i -

mately i n tile c e n t r e of t h e h u t , This was equipped wit'n a f u e l

t a n k of 5 - g a l (U,S, ) c a - x c i t y and a f l o a t - t y p e f u e l r e g u l a t o r

w i t h a n e i g h t p o s i t i o n Z i a l , The h e a t e r was v e n t e d t o a 6 - i n .

f l u e pTpe t e r i n i n a t i n g in a t r a n s i t i o n p i e c e a t t h e

7-ix1,

opening of t h e roof jack1'. An a u t o a a t i c d r a f t r e g u l a t o r

was i n s t a l l e d i n t h e f l u e pipe. I ~ l a n u f a c t u r e r s s p e c i f i c a t i o i i s f o r t h e spacz h e a t e r Nere a s f o l l o v ~ s : Height t o Centre of Vent Ou-iilet, i n . 30 3/4 O v e r - a l l S i z e , i n . Btu Outpu- p e r h o u r 55,000 Fuel Burning r a t e , q u a r t s p e r hour a t lol,v

1 / 7

depth 38

1/4

h e i g h t 40 1/2 rridth 30 a t h i g h 2.2 avg 1.1

Accessories t o t h e h e a t e r were: an automatic feel c o n t r o l , used. a s a n a l t e r n a t i v e t o manual o p e r a t i o n of t h e f u e l r e g u l a t o r , whereby on h e a t demand of a n e l e c t r i c t h e r m o s t a t t h e f u e l valve i s r e p o s i t i o n e d by an e l e c t r i c r e l a y from a " p i l o t flame" s e t t i n g t o t h e s e t t i n g previov-sly e s t a b l i s h e d manually on t h e f u e l r e t x l a t o r d i a l , and on s a t i s f a c t i o n of t h e t h e r ~ o s t a t t h e f u e l v a l v e r e v e r t s t o t h e l o w o r p i l o t p o s i t i o n ; and a c i r c u l a t i n g f a n , l o c a t e d vxder t h e h e a t t r a n s f e r s u r f a c e s of t h e hea-Ler, d r i v e n by a 1/40-hp 1 1 0 - v o l t

60-cycle m o t o r and having a ra-bed c a p a c i t y of 18,000 cu f t of

warm a i r p e r hr, by which some of t h e heated a i r i s dralm

downward and discharged in'Go t h e room h o r i z o n t a l l y through

a g r i l l e a few i n c h e s above f l o o r l e v e l .

Ventila-tion of t h e h u t was by liatu-ral f o r c e s o n l y ,

without t h e use of f a n s . Tne main p r o v i s i o n f o r a i r exhaust

was i n t h e s p e c i a l metal roof "jack" ( P i g .

4)

c o n t a i n i n g a n

11 1/4-in. square opening, c o n c e n t r i c w i t h t h e 7 - i n . f l u e gas

o u t l e t , which passed through t h e roof and t e m i n a t e d i n a

metal cowling f o r p r o t e c t i o n a g a i n s t p r e c i p i t a t i o n . Por a i r

supply a 4 - i n . d i a m e t e r h o l e was provided i n t h e f l o o r d i r e c - t l y

below t h e h e a t e r . Both o f t h e s e openings could b e cl-osed Tram

Qiside t h e h u t by metal covers. For a d d i t i o n a l o r a l t e r n a t i v e

v e n t i l a t i o n t h e openable por%ion 02 t h e 17,~indons could be used.

6. IJETHODS OF TEST

Tne t r i a l s were pla-med t o o b t a i n maximu-m information on tlie behaviour of tlie h u t under a l l weather condi3ions and w i t h t h e h e a t i n g and v e n t i l a t i o m equipmen-i; o p e r a t e d i n

d i f f e r e n t ways, -that i s , usiilg v a r i o u s combinations of h e a t e r a c c e s s o r i e s and v e n t i l a t i o n openinzs.

S i ~ c e dry bulb -hemperatwe v?as tile m o s t important

element of t h e weather, t h e g e n e r a l c l a s s i f i c a t i o n of wea-ther

s e v e r i t y was made a s f o l l o w s :

IJoderate weather

-

Approx. 10°F and above

Modera-tely s e v e r e vieatlier

-

Approx.

l o 0

t o -203P

Severe weather

-

Approx. -20°P and below

The v a r i o u s combinations of v e n t i l a t i o n openings used f o r t h e t r i a l s were a s f o l l o i ~ i s :

Condition Roof Ven-t P l o o r Oi3ening Vind ows

1 closed closed c l o s e d

2 c l o s e d c l o s e d open

3

open c l o s e d c l o s e d

4

open open c l o s e d

5

open c l o s e d open

Normal o p e r a t i o n of t h e h e a t i n g equipment was considered t o be manual f u e l c o n t r o l w i t h h e a t d i s t r i b u t i o n by n a t u r a l

convection, s i n c e t h e hu:t was in-Lended f o r use i n n o r t h e r n

l o c a t i o n s where e l e c t r i c power might n o t be a v a i l a b l e . The use of t h e e l e c t r i c t h e r m o s t a t f o r f u e l c o n t r o l and t h e h e a t e r c i r c u l a t i n g f a n was t o be r e s t r i c t e d t o s p e c i a l . t r i a l s

(d-esignated by s u f f i x e s T and

I?)

t o be compared w i t h t h e

s t a n d a r d t r i a l s having t h e same v e n t i l a t i o n arrangement.

During t h e t r i a l s t h e room t h e r m o s t a t was used more e x t e n s i v e l y t h a n o r i g i n a l l y planned t o achieve c l o s e r a i r temperature c o n t r o l and more s t a b i l i z e d t e s t c o n d i t i o n s .

To study t h e crawl space t e n p e r a t m e and i t s probable e f f e c t on permafrost, a s h o r t s e r i e s of t r i a l s ,

designated a s s e r i e s A , was run w i t h t h e p e r i m e t e r of t h e

crawl space open; f o r succeeding t r i a l s , s e r i e s 3 , t h e

perimeter was c l o s e d by banking-up of snow except f o r a s m a l l h o l e l e f t i n t h e banking t o admit f r e s h a i r f o r c o n d i t i o n s

4 and 6 tihen t h e f l o o r opening was i n u s e . The r e s u l t s of t h e

crawl space temperature measurements w i l l be t h e s u b j e c t of a

s e p a r a t e r e p o r t .

The t r i a l s were scheduled t o provide a s n e a r l y a s

p r a c t i c a b l e a t l e a s t one t r i a l under each of c o n d i t i o n s 1 t o

6

under each of t h e t h r e e b a s i c weather c l a s s i f i c a - L i o n s . The schedule c a l l e d f o r two three-day - t r i a l s and one n o n - t r i a l day

(Sunday) p e r week, wi-t;li a d d i t i o n a l l i o n - t r i a l days a t Christmas

and New Y e a r f s . During t h e t r i a l s , however, it w a s found

a d v i s a b l e t o reduce t h e d u r a t i o n of c o n d i t i o n 1 t r i a l s t o t w o

days each because of t h e u n p l e a s a n t a i r coiidi-Lions r e s u l t i n g

from reduced v e n t i l a t i o n . Each t r i a l day was considered a s

beginning a t 0800

hr

on t h e d a t e of %he t r i a l and c o n t i n u i n g

u n t i l t h e f o l l o w i n g day a t CBOO h r . Over t h e 161-day p e r i o d

from 25 October 1950 t o 3 A p r i l

1 9 5 1 ,

t h e r e were 6 t r i a l s

wi-l-h t h e crawl space banked and 38' t r i a l s wit'n it ~xnbanked.

During -the Ileati ng and v e l i t i l a t i o n t r i a l s t h e f o l l o w i n g me-teorological r e c o r d s were obtained u s i n g s t a n d a r d weat'ner

instrument s

.

O~xtside a i r ( d r y bulb ) temperature

01n"iside a i r r e l a t i v e i i m i d i t y Wind ( s p e e d ) and d i r e c t i o n Depth of snovv cover on roof General weather o b s e r v a t i o n s .

( a ) Room A i r Temperature and R e l a t i v e Humidity a t Control P o i n t The temperature and r e l a t i v e humidity of t h e room a i r were continuously recorded a t t h e " c o n t r o l point'' w i t h a hygro- therrnograph, with check r e a d i n g s once a week by means of a

s l i n g psychrometer. The d a i l y average a i r temperature and r e l a t i v e

humidity recorded a t t h e c o n t r o l p o i n t a r e sliown i n Fig. 6.

( b ) Room A i r Temperature D i s t r i b u t i o n

To o b t a i n t h e a i r terilperature d i s t r i b u - t i o i i t h o u g h o u t t h e h u t , dry-bulb t e m p e r a t u r e s were recorded by means of 24-gauge copper-constantan thermocouples l o c a t e d a t t h e 2 - , 30-, 60- and

95-in. e l e v a t i o n s above t h e f l o o r a t l o c a t i o n s 1 t o 10 shorn1

i n Pig.

3 .

The 30-in. l e v e l a t l o c a t i o n 1 was t a k e n a s t h e

" c o n t r o l p o i n t H . A t l o c a t i o n s 11 and 1 2 i n t h e s o u t h and n o r t h

porches r e s p e c t i v e l y , t e m p e r a t u r e s were recorded a t t h e 8 4 - i n . l e v e l only.

The thermocouple l e a d s were connected through a m u l t i p l e - bank switchboard t o a s t r i p - c h a r t type r e c o r d i n g potentiomet e r .

This 'Jas a s i x t e e n - p o i n t ins-trunent- w i t h a temperature range of -80°F t o 160°F o p e r a t i n g with a one-minute p r i n t i n t e r v a l .

The 64 thermocouples were a r r a n g e d i n t h r e e banks f o r

connection t o t h e r e c o r d e r . The bank c o n t a i n i n g t h e thermocouples

r e c o r d i n g t h e more importan$ t e m p e r a t u r e s remained connected t o t h e

r e c o r d e r f o r most of Lhe d s i l y t e s t p e r i o d , Tliree times d a i l y

a t 0800, 16C0, and 2200 hi-, t h e o t h e r banks were switched i n

c o n s e c u t i v e l y f o r 16 min each, t o r e c o r d t h e remaining temperatures. Tne o r i g i n a l t r i a l d i r e c t i v e c a l l e d f o r t h e a i r

t e m p e r ~ t u r e a t t h e " c o n t r o l p o i n t t i ( 3 0 - i n . e l e v a t i o n a t l o c a t i o n 1)

t o be mainJ6ained a s c l o s e l y a s p o s s i b l e t o 70°F f o r t h e d u r a t i o n

of t h e - I ; r i a l s , This ~ 2 s ~ d h e r e d t o f o r t h e e a r l y t r i a l s b u t

it was found t h a t t h e tempera-twe d i s t r i b u - t i o i i i n t h e hu.t was such t h a t i n f a i r l y s e v e r e n e a t h e r t h e -temperature a t t h e l e v e l

of t h e upper buiiks was a x o a f o r b a . b l y warm f o r s l e e p i n g . Beginning

4 December, t h e r e f o r e , %he con-brol p o i n t temperature f o r 'the n i g h t

p e r i o d , (2200 hr t o 0800 l?r t h e folloirfii?g day) was reduced t o

65'3'.

I t was o r i g i n a l l y intended t h a t t n e f u l l s e t of 4 8

temperatuxes recorded a t each 02 t h e t h r e e p e r i o d s of bank change, 0800, 1600, and 2200 h r would be used i n determining

t h e t e m p e r a t w e d i s - i - r i b u t i o n vvithin t h e b a r r a c k room and instrument

of t h e r e c o r d s , however, it was found t h a t i n many t r i a l s t h e temperature r e a d i n g s a t 0800 h r and 2200 h r coincided w i t h

changes i n s e t t i n g of t h e f u e l r e g i s t e r of t h e h e a t e r ( u n d e r

manual c o n t r o l ) and changes i n set-king of t h e therillostat ( i m d e r

t h e m o s ' t a t i c c o n t r o l ) so t h a t t e n p r a - L u r e s i n tlie hut Itrere

r i s i n g o r f a l l i n g d u r i n g t h e s e p e r i o d s . Furthermore, a t t h e s e

two p e r i o d s of t h e day, t h e hut temperature varLa$ions were a f f e c t e d by t h e opening anC c l o s i n g of t l i e dooi-s of t h e hu-l- due

t o t h e normal nlovenents of %lie personnel. Consequeni;ly t h e only

f u l l s e t of /I-8 temperature r e a d i n g s which cov-ld be r e l i e d upon

t o i n d i c a t e t h e temperature pat-i;ern m ~ d e r r e a s o n a b l y s t e a d y

coliditions were t h o s e recorded a t 1600 h r

(4

P . M . ) . These

4

p.m. r e a d i n g s , when p l o t t e d f o r each t r i a l day u s i n g room a i r

(dnd~-b~-tlb ) tenlperature a s ~ b s c i s s a and e l e v a t i o n above t h e f l o o r

a s o r d i n a t e , r e s u l t e d i n curves of v e r t i c a l temperature g r a d i e n t

f o r each of t h e t e n room l o c a t i o n s . P i ~ w r e s

7

t o 11 i n c l u s i v e

have been selec-be8 t o i n d i c a t e how v e r t i c a l room temperature g r a d i e n t s were a f f e c t e d by t h e severiJGy of t h e weather, t h e use of t h e h e a t e r c i r c u l a t i n g f a n , and t h e degree of v e r l t i l a t i o n provided.

To f u r t h e r i l l u . s t r a t e t h e d i s - t r i b u t i o n of t e m p e r a t u r e s

throughout t h e h u t , t h e temperatures i n Bigs. 8 and

9

f o r

l o c a t i o n s 1 t o

7

have been r e p l o t t e d i l l P i g s . 1 2 and.

1 3

a s

i s o J ~ h e r m a l l i n e s a l o n g t h e l o n g i t u d i n a l and t r a n s v e r s e c e n t r e l i n e s

of t h e b a r r a c k roorn.

( c ) Surface Temgeratures

Measurements mere a l s o nade, w i t h a c o n t a c t pyromeJGer, of t h e i n s i d e s u r f a c e t e n p e r a t w e s of t y p i c a l p a n e l s of t h e

enclosure wider a v a r i e t y o f ! i ~ e a t h e r c o n d i t i o n s . D i f f e r e n c e s

between a i r and su-rface

t

empera-Lures weye q u i t e s m a l l , n o t a b l y f o r

t h e windows. Surf a c e temperature g r a d i e n t s i n t h e v i c i n i t y of

framixg mere a l s o s m a l l . Surface t e n p e r a t u - r e s obtained w i t h t h i s

instm-tnent a r e r e l a t i v e l y c m d e and a r e lilcely t o be sonevdmt

h i g h e r t h a n t h e t r u e s u r f a c e temperatu-re s

.

A i r Q u a l i t y

No r e g y l a r measurenents were made t o a s s e s s t h e a i r

q u a l i t y i n t h e hv:L d u r i n g t h e h e a t i n g and v e n t i l a t i o n t r i a l s .

Observations oQ odour in2l-ensity were made d u r i n g t h e t r i a l s ,

holi:lever, and it was noted t h a t t h e h u t remailled corn-paratively

odour f r e e except d u r i n g a l l c o n d i t i o n 1 t r i a l s and some c o n d i t i o n

2 t r i a l s . Under c o n d i t i o n 1, V ~ i t h a l l v e n t s and windows c l o s e d ,

t i l e r e was a s e r i o u s acc1~-mulation oi" odours from tobacco smolce,

p e r s p i r a t i o n , and o i l y c l o t l i i n g , so o b j e c t i o n a b l e t h a t c o n d i t i o n 1 t r i a l s were reduced t o tv~o-day s i n s t e a d o f three-day! s d u r a t i o n . The o d o w i n t e n s i t y under c o n d i t i o n 2 n a s n o t a s g r e a t b u t i n

m o s t t r i a l s was o b j e c t i o n a b l e and t h e r e were ccmplaints from $he h u t occupants of Isnot enough f r e s h a i r " p a r t i c v . l a r l y f o r s l e eping.

A s a h e a l t h p r e c a u t i o n d u r i n g c o n d i t i o n 1 t r i a l s t h e a i r i n t h e h u t was sampled and analyzed wi%h a n O r s a t a p p a r a t u s

about every t h r e e hours. There was no undue r i s e i n t h e C02

c o n t e n t of t h e a i r . Por f u r t h e r s a f e t y , a p o r t a b l e CO i n d i c a t o r

u s i n g yellow-to-green c a p s u l e s was used t o sample t h e a i r a t v a r i o u s p o s i t i o n s i n t h e room n e a r t h e h e a t e r , samples b e i n g t a k e n once every hour -throughout t h e t r i a l . No s i g n i f i c a n t

amount of C O was detec-Led.

With t h e i n s t r u m e n t a t i o n a v a i l a b l e it was n o t p o s s i b l e

t o measure t h e o v e r - a l l r a t e of a i r change i n t h e h u t . Measurements

were made, however, t o es-bimate t h e a i r exhausted through t h e roof v e n t and f l u e p i p e , t h e l a t t e r c o n s i s t i n g of a i r t h r o u g h t h e d r a f t r e g u l a t o r and a i r f o r combustion.

To determine t h e a i r exhausted through t h e roof v e n t

a vane-type anemometer was mounted

i n

one c o r n e r of t h e roof

jack, approximately midway betmeen t h e square o u t e r c a s i n g

and t h e f l u e pipe. The number of f e e t of a i r p a s s i n g t h r o u g h t h e

anemometer was o b t a i n e d f o r each t r i a l day. E s t i m a t i o n of a i r

f l o w from t h e anemometer r e a d i n g s was su.b j e c t t o c o n s i d e r s b l e e r r o r

because of t h e i r r e g u l a r i t y o f t h e c r o s s - s e c t i o n of t h e ven-b

opening and t h e l o c a t i o n of t h e anemometer which was n e a r t h e e n t r a n c e of t h e roof jack t o f a c i l i t a t e r e a d i n g of t h e d i a l s . Comparison of e a r l y t r i a l s w i t h roof v e n t open and closed showed t h a t t h e c a l c u l a t e d a i r flow through t h e roof ven* based on

anemometer r e a d i n g s was much h i g h e r -than t h e h e a t balance could

j u s t i f y . A c o r r e c t i o n f a c t o r , e q u a l t o C.5, was t h e r e f o r e

e s t a b l i s h e d .

The temperature of t h e a i r p a s s i n g 0u.t $he roof v e n t was given by t h e average of t h e recorded r e a d i n g s of two

thermocouples mouvlted i n t h e lower s e c t i o n of t h e roof v e n t , one

i n each oI" two c o r c e r s . These were pro-l-ec-bed a g a i n s t d i r e c t

r a d i a t i o n from -the f1u.e pipe by cylindrical n e t a l s h i e l d s open

a t b o t h ends. A f l a t r i n g of s h e e t m e t a l , approximately 1 2 i n .

i n diameter was assembled around t h e f l u e pipe a s h o d - d i s t a n c e below t h e lotver s e c t i o n 03 t h e roof v e n t t o a s s i s t i n mixing t h e h i g h e r - v e l o c i t y higher-temperatux-e a i r r i s i n g n e x t t o t h e f l u e p i p e w i t h t h e l o w e r - v e l o c i t y lower-tempera-ture room a i r , and

t o give s t e a d i e r r e a d i n g s of exhaus-: a i r t e m p e r a t u r e and v e l o c i t y . Average temperatme of t h e a i r p a s s i n g t k o u g h t h e roof v e n t

v a r i e d between a maximum of 140"P d u r i n g s e v e r e weather and a

miniroum of 72'3' _{i n moderate weaLher}

with

_{an o v e r - a l l average}

f o r t h e 161-day p e r i o d of approximately 105'F.

A vane-type anemome-ter s i m i l a r t o t h a t used f o r measuring a i r p a s s i n g through t h e roof v e n t was used t o determine t h e f e e t

of a i r passing through t h e d r a f t r e g u l a t o r . Since t h e d r a f t r e g u l a t o r presented an i r r e g u l a r l y shaped opening, a

s p e c i a l entrance l ~ i p e of c i r c u l a r c r o s s - s e c t i o n was f a b r i c a t e d

and i n s t a l l e d over t h e frame of t h e d r a f t r e g u l a t o r . The

anemometer was mounted in t h e t h r o a t of t h i s circu1a.r opening. a s

shown i n Fig. 2. Temperature of -the d r a f t r e g u l a t o r a i r was

given by readings of a d j a c e n t rcom a i r tsmperature thermocouples.

Tne a i r used. f o r combus~~ion was determined by c a l c u l a t i o n

from records of f l u e gas composition and t h e u l t i m a t e a n a l y s i s of t h e f u e l u s i n g t h e r e l a t i o n s h i p :

where At = T o t a l weigh* of a i r , i n c l u d i n g excess,

( l b per l b of f u e l )

( h r 2 I v = Nitrogen in f l u e gas ( p e r cen-t by v o l )

(C02)v = Carbon dioxide i n f l u e gas ( p e r cent by v o l )

( C O ) v = Carbon inonoxid-e i n f l u e gas ( p e r cent by v o l )

C = Tleight of carbon i n f u e l ( l b p e r l b of f u e l ) ,

Flue gas analyses were made t h r e e times durLng each

t r i a . 1 day with an Orsat apparatu-s t o o b t a i n r e c o r d s of C02, 02,

and CO. Since t h e a.nalgses showed changes i n propor-tions - - o f t h e

various gases f o r d i f f eren-b 2u.el cona~mption r a t e s , it as

necessary t o i n t e r - r e l a t e t h e value of

Ai

v!i-Lh f u e l c o n s u ~ p t i o n .

From a l a r g e number o f f l u e gas a r a l y s e s on vari0v.s - t r i a l days

t h e value of t h e to-La1 rnei&t 02 coinbus-bion a i r ( A t ) was found

and p l o t t e d agains-> t h e f u e l consumption r a t e f o r each i n s t a n c e .

From t h e s e many p o i n t s , a c u r r e was plo-tte6 t o g i - ~ 3 t h e

r e l a t i o n between At and Tu-el consunip-tion r a t e , Then f o r each

increnen-L of f u e l c o c s m p t i o n f o r 2ny one t r i a l day a value of

A t was f olmd from t h e cv3-ve and t h e corresponding voluae of

combust-ion a i r c a l c u l a t e d , The s~:rr,mc?~~i-.-~- of t h e s e increments

t h e n gave: -?fie to-La1 vol~~-ine of c ~ n b u s t i o - ~ a i r f o r each " c i a 1 day.

This i s shorm in Pig,

1 4 .

The volume of a i r , r e f e r r e d t o a d e n s i t y of 0.075 l b p e r cu f-b exhau-sted throu-gh t h e roof v e n t and f l u e pipe Inas

t o t a l l e d f o r each t r i a l day and t h e average measured v e n t i l a t i o n

r a t e f o r t h e h u t computed on t h i s b a s i s , Tne result-s a r e shown i n

Pig. 6. It should be noted t h a t t h i s does not include a i r

open windows. Values of t h e measured v e n t i l a t i o n r a t e were p l o t t e d a g a i n s t i n s i d e - o u t s i d e t e m p e r a t u r e d i f f e r e n c e .

Although t h e r e s u l t s showed a wide s c a t t e r t h e r e was a g e n e r a l i n c r e a s e i n measured v e n t i l a t i o n r a t e with d e c r e a s i n g o u t s i d e

t e m p e r a t u r e f o r most t r i a l c o n d i t i o n s . A s t r a i g h t l i n e

r e l a t i o n w a s assumed and c u r v e s dra-ivn t h r o u g h t h e p o i n t s by t h e method of l e a s t s q u a r e s ( F i g . 1 5 ) .

1 0 . HFAT BALANCE

A h e a t b a l a n c e f o r t h e h u t w a s d e t e r m i n e d f o r e a c h

t r i a l day. The t h r e e main components of t h e t o t a l h e a t i n p u t t o

t h e h u t were: t h e h e a t c o n t e n t of t h e f u e l o i l burned

i n

t h e

h e a t e r , t h e h e a t e q u i v a l e n t of e l e c t r i c a l energy u s e d i n t h e h u t , m a i n l y f o r l i g h t i n g p u r p o s e s , and t h e body h e a t e m i t t e d by -the

o c c u p a n t s of t h e h u t . KO a c c o u n t was t a k e n of h e a t g a i n due t o

s o l a r r a d i a t i o n t h r o u g h t h e w h d o ~ v s .

To measure f u e l c o n s w p t i o i i t h e f u e l t a n k was equipped

w i t h a simple f l o a t - r o d d e v i c e c a l i b r a t e d i n t e n t h s of g a l l o n s .

This was r e a d a t t h e b e g i n n i n g and end o f each t r i a l day and

b e f o r e and a f t e r e a c h manual f i l l i n g of t h e t a n k .

An 8-oz sample of t h e f u e l was drawn f r o m t h e l a r g e

s t o r a g e t a n k a f t e r e a c h f i l l i n g by t a n k t r u c k , t l i e

samples l a t e r b e i n g s e n t t o Ottawa l a b o r a t o r i e s f o r u l t i m a t e a n a l y s i s and f o r h e a t c o n t e n t and d e n s i t y d e t e r m i n a t i o n s . The h e a t c o n t e i i t and d e n s i t y r e s p e c t i v e l y were 1 8 , 5 0 0 B t u

p e r l b and 6.94 l b p e r cu f t up t o 9 J a n u a r y and 18,440

B t u p e r l b and 7.10 l b p e r c u f t f o r t h e r e s t of t h e t r i a l s . F u e l consumptio:~ f o r t h e 161-day t r i a l p e r i o d i s shown g r a p h i c a l l y i n P i g . 16. For comparison w i t h t h e f u e l c o n s ~ r n p t i o n c u r v e , t h e c u r v e of degree-days (65OP b a s e ) f o r t h e t r i a l p e r i o d h a s been i n c l u d e d and a f a i r l y c l o s e r e l a t i o n i s a p p a r e n t .

To measure e l e c t r i c a l power consumption, a s t a n d a r d m u l t i p l e d i a l wat-t-hour m e t e r was i n s t a l l e d vihich r e g i s t e r e d t h e

t o t a l power s u p p l i e d t o t h e h u t . Readings were t a k e n t h r e e t i m e s

a d a y i m e d i a t e l y f o l l o r r ~ n g f u e l r e a d i n g s , and a t t h e b e g i n n i n g

and end of e a c h t r i a l , A l l e l e c t r i c a l e n e r g y consumed was

c o n v e r t e d i n t o h e a t u n i t s f o r h e a t b a l a n c e purposes. D a i l y

e l e c t r i c i t y consumption

i n

t h e h u t i s sho~rm i n Fig. 16.

An e s t i m a t e of t h e d a i l y h e a t i n p u t from p e r s o n n e l

was made'based on t h e i r occupancy h a b i t s . It was assumed t h a t

p e r s o n n e l would e m i t h e a t a t - t h e - r a t e of 400 B t u p e r h r p e r man

d u r i n g waking h o u r s a n d 300 B t u p e r hr d u r i n g s l e e p i n g h o u r s . For a l l t r i a l s t h z p r o p o r t i o n of t h e t o - t a l d a i l y h e a t

i n p u t a t t r i b u t a b l e t o perso,mel v a r i e d from 2 t o 8 p e r c e n t w i t h

i n p u t was approximately

3

t o 1 2 p e r c e n t w i t h a rough average of

8 p e r c e n t .

The v a r i o u s h e a t l o s s e s e n t e r i n g i n t o t h e h e a t balance calcula-Lions f o r t h e h u t were a s follo1,vs:

Heat l o s s throu* roof vent.- Tne h e a t r e q u i r e d t o r a i s e t h e

t e m ~ e r a t u r e of $he v e n t i l a t i o n a i r p a s s i n g out t h e roof v e n t

from o u t s i d e temperature t o room temperature.

Heat l o s s through

-

d r a f t r e g u l a J ~ o r o - The h e a t r e q u i r e d t o r a i s e

t h e temperature of t h e a i r p a s s i n g through t h e d r a f t r e g u l a t o r from o u t s i d e temperature -iio room t e m p e r a t u r e ,

Heat l o s s t o combustion

--

a i r . - The h e a t r e q u i r e d t o r a i s e t h e

temperature oY t h e a i r used by %he h e a t e r f o r combustion from ouJ'cside tempe radiure t o room tempem.ture,

Heat l o s s t o f l u e

g_a~.-

The h e a t con4cai-ned i n t h e c o n b u s t i o i ~ gases

p a s s i n g u.p t h e s'iack, r e l a t i v e %o room t e m p e r a t u r e ,

Heat l o s s through ~ t : ~ ~ ~ . c t w e .

-

The h e a t l o

t ~ i ~windov~s and l d ~ g

f l o o r of t'ne h u t ,

h e a t t r a n s n i s s i o n r o o f and

Unaccoun-ted f o r hea'; l o s s e s occurred due -to a i r i n f i l t r a t i o n and,

d u r i n g many of t h e t r i a l s , v e n t i l a , t i o n a i r through open windows. The h e a t l o s s e s attribu-b-table t o a i r e n t e r i n g t h e

roof v e n t

,

d r a f t regula-Lor, and h e a t e r were calcula-ted i n d i v i d u a l l y

from t h e r e c o r d s of 2 . i r volu.ile and t e m p e r a t ~ r e p r e v i o u s l y

r e f e r r e d -Lo,

( a ) Hea-l- Loss t o Flue Gas

Va1-v.e~ of percell-ba ge C02 viere ob-tained from a n a l y s i s

of -the f l u e gas ma& t h r e e -Limes cially n i t h t h e d r a f t r e g u l a t o r

a d j u s t e d t o give t h e draP-b recomroended by t h e na;fiufacturer.

Flue gas temperatures ;>:en t a k e n a t %he same i n t e r v a l s by means

of a mcrcwy-in-glass l a b o r a J ~ o r y ther:oorneter mouiited i n t h e

f l u e belo-rf t h e d r a f t regvLz?ior, From t h e s e GO2 and temperature

r e a d i n g s t h e cornbv.stion ePf i c i e n c y was determined f -ram c w r e s

given i n Chapter

14

02 t h e

1955

3-SK4.E ''C;v.Ldet:, p ~ b l i s h e d by t h e

American Socie-tg of Eea-Cing c?nc'~ Air ConcZii-i-oning Engineers.

Slnce 2 c l o s e r e c o r d of f u e l consurlp'iion Yas Irept,

i-t was p o s s i b l e t o r e l a - t e Che r a t e of fu-el coosu.mp-tion t o Yne

heaAier coabustion e f f i c i e n c : ~ _., a s de'ce-mlined from t h e i n s t a n t a n e o u s

f l u e gas aizaljfses and -Lenpe-ra'u~~es, over a wide range of v a l u e s

froni l o w h e a t e r se-i-tLng t o h i g h h e a t e r s e - k t - i ~ g . From t h e _-

combustion e f f i c i e n c y cvxve +-I- ulius es-tablished ? o r t h e h e a t e r

o f f u e l consumption, over -the e n t i r e day, assuming t h a t f o r any one h e a t e r s e t t i n g t h e f u e l r a t e was e s s e n t i a l l y c o n s t a n t . The h e a t l o s s t o f l u e gas f o r each increment was t h e n r e a d i l y

determined and t h e increments t o t a l l e d f o r tach t r i a l day,

( b ) Heat Loss Through t h e S t r u c t u r e ( H s )

The t o t a l h e a t l o s s by transmission through t h e s t r u c t u r e comprised l o s s e s through t h e r o o f , w a l l s , windows and doors, and t h e f l o o r . These were c a l c u l a t e d f o r each day of t h e t r i a l s , and were based on t h e average temperature

d i f f e r e n c e between t h e a i r i n s i d e and o u t s i d e of each b u i l d i n g component, m u l t i p l i e d by t h e a r e a and by t h e c a l c u l a t e d

o v e r - a l l h e a t transmission c o e f f i c i e n t of each component.

The o v e r - a l l h e a t -transmission c o e f f i c i e n t s

("u"

v a l u e s )

f o r t h e b u i l d i n g s e c t i o n s were c a l c u l a t e d using procedures

and thermal c o e f f i c i e n t s given i n Chapter

9

o f t h e

1955

ASHAE

Guide. These v a l u e s a r e given i n Table I.

The U values of t h e roof panel with d i f f e r e n t

amounts o f snow cover were a l s o c a l c u l a t e d and t h e a p p r o p r i a t e

value used, based on snow depth measurements. Table I g i v e s

t h e value f o r an 8-inch snow cover.

I n obtaining t h e average i n s i d e a i r temperature

a d j a c e n t t o any component a "wei@tedfl average was e s t a b l i s h e d by f i r s t d i v i d i n g t h e i n t e r i o r s u r f a c e s of t h e h u t i n t o t e n zones, t h e average i n s i d e a i r temperature value f o r each zone

being based on t h e readings of a d j a c e n t thermocouples. I n

c e r t a i n zones where thermocou-ples had n o t been i n s t a l l e d t h e

-bemperatures used were those of zones having s i m i l a r temperatures

a s i n d i c a t e d by t h e p a t t e r n of isotherms. Two thermocouples

were used t o obtain crawl space a i r temperatures.

Heat transmission through t h e s t r u c t u r e was c a l c u l a t e d

f o r each t r i a l day. No account was t a k e n o f h e a t storage i n the

s t r u c t u r e s i n c e i t s e f f e c t was small when considered over t h e

s e v e r a l days of each t r i a l condition. The h e a t l o s s e s through t h e

components a s a percentage of t h e t o t a l c a l c u l a t e d heat l o s s

through t h e struGture weEe a s follows: r o o f , 28 t o

4 1

p e r c e n t ;

nralls, windows and doors, $1 t o

59

p e r c e n t ; f l o o r with crawl spa

unbanked,

19

t o 25 p e r c e n t ; f l o o r w i t h crawl space banked,

8 t o 2 1 p e r c e n t ,

he

t o t a i c a l c u l a t e d h e a t l o s s through t h e

s t r u c t u r e i s shorm i n Fig, 18,

The average d i s t r i b u t i o n o f t h e measured heat l o s s e s

during severe weather with t h e h u t perimeter banked i s shown i n Table

11. The d r a f t r e g u l a t o r h e a t l o s s was l e s s than 1 p e r c e n t i n each

The h e a t f o r v a r i e d q u i t e widely f r o m day

t o day. This was i n e v i t a b l e because, i n a d d i t i o n t o e r r o r s i n

measurement, no account was t a k e n o f such f a c t o r s a s i n f i l t r a t i o n ,

v e n t i l a t i o n through open windows, h e a t s t o r a g e , and s o l a r and

n i g h t sky r a d i a t i o n exchange. The d i f f e r e n c e between t o t a l h e a t

i n p u t and t o t a l h e a t l o s s was g e n e r a l l y l e s s t h a n 1 0 per c e n t

and i n most i n s t a n c e s l e s s than

5

per c e n t . I t was o f t e n

n e g a t i v e , e s p e c i a l l y under severe weather conditions.

A d i r e c t l i n e a r r e l a t i o n between t h e t o t a l d a i l y

h e a t requirements and i n s i d e - o u t s i d e temperature d i f f e r e n c e was

apparent f r o m p l o t t e d r e s u l t s . This i s shown i n Pig. 19, t h e

curves having been located by t h e method of l e a s t squares. 11. D I S C U S S I O N OF RXSULTS

( a ) Environment

A study of temperature g r a d i e n t curves such a s t h o s e

shown i n Pigs. 7 t o 11 l e a d s t o t h e following observations vhth regard t o t h e h o r i z o n t a l temperature d i s t r i b u t i o n w i t h i n

t h e hut. A t t h e 2-in. l e v e l , temperatures ranged from 42

t o 68OP f o r severe weather - t r i a l s . Temperatures f o r moderately severe and moderate weather were w i t h i n t h e range of 49 t o 70°P.

A t t h e 30-in. l e v e l room a i r temperatures were w i t h i n t h e range of 60 t o 75OP i n a l l t r i a l s . The v a r i a t i o n i n a i r temperature throughout t h e hut a t t h i s l e v e l was approximately 11 degrees

f o r severe weather t r i a l s , 8 degrees f o r moderately severe

weather, and

5

degrees f o r moderate weather.

lit t h e 60-in. l e v e l , a i r -temperatures ranged from

67 t o 80°P i n a l l t r i a l s , b u t i n i n d i v i d u a l t r i a l s t h e v a r i a t i o n throughout t h e hut r a r e l y exceeded 7 degrees r e g a r d l e s s of t h e

s e v e r i t y of t h e weather. A s was t h e case a t t h e 30-in. l e v e l ,

l o c a t i o n s

9

and

3

a t t h e 60-in. l e v e l showed i n many t r i a l s t h e

h i g h e s t and lowest temperature readings although t h e temperature

a t l o c a t i o n 10 i n t h e instrument room was lower t h a n t h a t o f

locatioi?.

9

on some occasions.

A t t h e 95-in. l e v e l , a i r temperatures f o r t h e m a j o r i t y of l o c a t i o n s i n a l l t r i a l s were between 70 and 95OP, although

f o r t h e severe weather t r i a l s t h e temperature a t some l o c a t i o n s ,

notably l o c a t i o n 6 , reached a s high a s 117'3'. The extreme tempe-

r a t u r e s a t l o c a t i o n 6 were due t o t h e aluminum beams o f t h e

roof s t r u c t u r e vrhLch pocketed hot a i r r i s i n g f r o m t h e h e a t e r

and channelled it a c r o s s t h e room, The use

of

t h e h e a t e r f a n ,

a s i l l u s t r a t e d i n Pig.

9 ,

r e s u l t e d i n a marked decrease i n

a i r temperatures a t t h e 95-in. l e v e l ,

I n general t h e g r e a t e s t a i r temperature g r a d i e n t from f l o o r t o c e i l i n g was found a t l o c a t i o n s 6 and 7 , due mainly t o

g r a d i e n t oZ each t r i a l was shown by l o c a t i o n 10 except i n t h e severe weather t r i a l when t h e f a n was i n operation

( F i g o

9 ) .

When t h e f a n was n o t i n operation t h e v e r t i c a l a i r temperature g r a d i e n t s between t h e 30- and 60-in. l e v e l s were much l e s s than between e i t h e r t h e 2- and 30-in. l e v e l s o r

t h e 60- and 95-in. l e v e l s , being approximately

5

degrees f o r

severe weather,

4

degrees f o r moderately severe weather, and 3

degrees f o r moderate weather.

The o v e r - a l l g r a d i e n t f r o m f l o o r t o c e i l i n g increased

with i n c r e a s i n g s e v e r i t y of weather and with i n c r e a s i n g v e n t i l a t i o n r a t e from condrtions 1 t o 6 , except when t h e f a n was i n

operation. The use of t h e f a n g r e a t l y minimized t h e v e r t i c a l

temperature gradien-ts throughout t h e h u t ,

Under s i m i l a r conditions of weather and v e n t i l a t i o n ,

t h e mean room a i r temperature g r a d i e n t was g r e a t e r t h e

perimeter of t h e crawl s p m e was not banked t h a n when it w a s

banked,

Surface temperatures of t h e s e l e c t e d f l o o r panel were

considerably h i g h e r t c ~ v a r d t h e c e n t r e l i n e of t h e hut t h a n a t t h e

w a l l end. This i s believed t o be due i n p a r t t o t h e proximity

of t h e panel t o t h e h e a t e r . Floor s u r f a c e temperatuxes -,xried

fron?

48

t o 64OF a t t h e wall end of %he panels and L'rorn 58 t o

74'3'

a t t h e h u t c e n t r e l i n e . Floor telnperatures were 'nigher w i t h t h e

h u t perimeter banked than with it rnbanlred. 12 moderate weather

t h i s d i f f e r e n c e was from 1 t o 8 O P while under more severe weather

conditions t h e i n c r e a s e due t o banking w a s from

4-

t o as h i g h a s

1 3 degrees.

Rela-tive humidity v a r i e d d i r e c t l y with t h e number o f

occupants, s i n c e t h e amount of moisture v ~ i t h i n t h e hut was mainly

due t o t h e r e s p i r a t i o n and p e r s p i r a t i o n of t h e occupants, and

t o a small degree t o t h e melting and- evapcration of snow from

t h e f l o o r and from c l o t h i n g a f t e r persoilme1

had

entered frcm

outside. P,lso, t h e r e l a t i v e hurnidj-t jr vras s t r o n g l y influenced

by t h e degree o f h u t - ~ e r ; t i l a t i o n a f f o r d e d by t h e v a r i c u s t r i a l

conditions, These r e l a t i o n s h i p s betwee-n nlmber of occupants,

v e n t i l a t i o n r a t e , and r e l a t i v e hun-idi-by a r e more evident from a study o f Fig. 6, Ylhere v e n t i l a t i o r ? r a t e and number o f occupants remained roughly c o n s t a n t , t h e r i s e s and f a l l s i n i n s i d e r e l a t i v e humidity can (be a t t r i b u t e d t o correspoiiding s h a r p r i s e s an4

f a l l s i n t h e outdoor a i r temperature which occurred u s u a l l y

about one day previous,

( b ) VenUcilatlcn -Rate

l!leasued v e n t i l a t i o n r a t e o f t h e hu-t v a r i e d f r o m a

mintm~m culder condition 1 ( r o o f v e n t , f l o o r opening, and windows

c l o s e d ) t o a maxim7m unaes c o n d i t i o n

6

(roof v e n t , f l o o r opening,

The roof v e n t was r e s p o n s i b l e f o r t h e major p a r t of t h e t o t a l measured v e n t i l a t i o n . On days when t h e roof v e n t was closed t h e a i r r e q u i r e d f o r combustion was t h e major

component. A i r q u a n t i t i e s through t h e d r a f t r e g u l a t o r were s o small a s t o be i n s i g n i f i c a n t except on t r i a l days when t h e roof v e n t was closed.

Prom Pig. 15

it

i s apparent t h a t under c o n d i t i o n s 1

and 2 t h e measured v e n t i l a t i o n r a t e was more o r l e s s independent of o u t s i d e temperature c o n d i t i o n s ; w i t h t h e roof vent open

( c o n d i t i o n s

3

t o 6 ) , however, v e n t i l a t i o n r a t e i n c r e a s e d w i t h d e c r e a s i n g o u t s i d e temperature.

A s bas been i n d i c a t e d v e n t - i l a t i o n r a t e measurements were n e c e s s a r i l y crude. E x f i l t r a t i o n , through c r a c k s i n t h e c o n s t r u c t i o n a r o m d windows and doors, was probably a n e g l i g i b l e component of t h e t o t a l a i r change, i n view of t h e t i g h t n e s s of c o n s t r u c t i o n and weather s t r i p p i n g and t h e a i r exhaust provided by t h e roof jack i n most t r i - a l s . However, t h e correc-tion f a c t o r of 0.5 a p p l i e d t o t h e roof jack anemometer t o o k such e x f i l t r a t i o n i n t o account t o some e x t e n t s i n c e

it

was s e l e c t e d t o give t h e b e s t agreement- on t h e h e a t balance f o r t h e many t r i a l s i n which

windows were closed.

V e n t i l a t i o n rat-e measurements ignored e x f i l t r a t i o x through doors d u r i n g use and through open windows. The volume of such e x f i l t r a t i o n w i l l depend on what e x f i l t r a t i o n e x i s t s through o t h e r openings and upon t h e wind and outdoor temperature

c o n d i t i o n s .

The i n c r e a s e i n measured v e n t i l a t i o n r a t e due t o open wind-ows w i t h t h e roof v e n t open can be seen i n Fig. 15 by

comparing curves

3

and

4

w i t h 5 and 6. Conparison of t h e corresponding curves i n Fig, 19 provides a crude index of t h e i n c r e a s e i n a c t u a l v e n t i l a t i o n r a t e due t o open windows. F o r example, a t a n i n s i d e - o u t s i d e temperature d i f f e r e n c e of 100°P, t h e v e n t i l a t i o n a i r volume corresponding t o t h e d i f f e r e n c e in h e a t i n p u t s beinreen curves

3

and 5 o r

4

and 6 of Pig. 1 9 i s

approximately 55,000 c u f t p e r day. This conpares w i t h a d i f f e r e n c e i n measured v e n t i l a t i o n r a t e i n Pig. 15 of about 30,000 cu f t

p e r day. Thus t h e unmeasured a i r volume due t o e x f i l t r a t i o n through doors and windows was roughly 25,030 cu f t p e r day under t h e s e

c ondi-i; io n s .

Comparison of curves 1 and 2 i n Pig, 15 i n d i c a t e s

t h a t opening of windows had l i t t l e e f f e c t on measured v e n t i l a t i o n r a t e s und-er "buttoned-up'' c o n d i t i o n s . However, t h e open windows d i d i n f a c t provide a s u b s t a n t i a l amount of v e n t i l a t i o n a s

i n d i c a t e d by t h e d i f f e r e n c e i n h e a t requirements f o r t h e same two c o n d i t i o n s shovm i n curves 1 and 2 of Pig. 19.

( c ) Heat Requirements

Figuxe

1 9

shows t h a t t h e d a i l y h e a t i n p u t was a

minimum under c o n d i t i o n 1 and i n c r e a s e d a s t h e means f o r

v e n t i l a t i o n were i n c r e a s e d . The i n f l u e n c e of t h e f l o o r

opening on t h e d a i l y h e a t i n p u t appeared t o be s l i g h t , t h e

d i f f e r e n c e between curves 3 and

4

and a g a i n between

5

and 6

probably b e i n g due t o e r r o r s i n measuremen-b and s c a t t e r

of p o i n t s . Conparing curves 3 and 3-P, t h e o p e r a t i o n of t h e

c i r c u l a t i n g f a n appeared t o have reduced i n p u t requirements t o some e x t e n t , a t l e a s t a t t h e h i g h e r i n s i d e - o u t s i d e a i r temperature d i 5 f e r e n c e s .

Since t h e r e were only a few t r i a l s f o r each c o n d i t i o n number i n which t h e h u t p e r i m e t e r was l e f t unbanlced, t h e number

of p o i n t s was i n s u f f i c i e n t t o p l o t a curve i n each case. The

r e c o r d s show. however. t h a t t h e h e a t i n n u t s f o r t h e unbanked p e r i m e t e r t r i a l s , when compared with t h o s e of t h e corresponding t r i a l s when t h e h u t p e r i m e t e r was banked, were c o n s i s t e n . t l y h i g h e r f o r s i m i l a r weather c o n d i t i o n s .

I t should be kept i n mind t h a t t h e d a i l y h e a t i n p u t i n Pig. 19 i n c l u d e s t h e f u l l h e a t equ-ivalent of t h e f u e l burned, h e a t i n t h e f l u e gas having been regarded a s a h e a t l o s s f o r

purposes of t h i s a n a l y s i s . Thus t h e h e a t a v a i l a b l e f o r h e a t i n g

t h e h u t was l e s s t h a n t h e h e a t i n p u t v a l u e by t h e anount of t h e f l u e gas l o s s .

Table I1 shows t h a t %he s t r u - c t u r e accounted f o r t h e

l a r g e s t percentage of t h e t o t a l h e a t l o s s under a l l t r i a l

c o n d i t i o n s . These h e a t l o s s e s through t h e s t u u c " ~ u r e o b t a i n e d

from calcula-Led U v a l u e s , a r e shovm a s c u i v e s i n Pig. 18.

S t r u c t u r a l h e a t l o s s e s f o r c o n d i t i o n 1 t r i a l s can a l s o be determined by s u b t r a c t i n g o t h e r h e a t l o s s e s from t h e h e a t i n p u t f i g u r e s .

Values obtained i n t h i s may have been p l o t t e d a s i n d i v i d u a l

p o i n t s i n Pig. 18. The r e s u l t s a t t h e extreme l e f t were o b t a i n e d

w i t h no snow cover, while t h o s e a t t h e c e n t r e and extreme r i g h t were obtained w i t h from 2 t o 8 i n . of snow on t h e r o o f .

Agreement w i t h t h e curves based on c a l c u l a t e d f i g u r e s i s r e a s o n a b l y

good*

( d ) Heating System Performance

I n g e n e r a l , t h e performance of t h e h e a t i n g system i n t h e h u t under t e s t was s a t i s f a c t o r y throughout t h e f u l l t r i a l period.

The c a p a c i t y of t h e h e a t e r was adequate t o ensure proper temperatures i n t h e h u t under a l l weather c o n d i t i o n s

experienced. Indeed, t h e r e was s u f f i c i e n t r e s e r v e c a p a c i t y t o

comTor-table temperatures even during t h e most severe weather, On t h e whole, t h e h e a t i n g system was e a s y t o operate

and t o maintain, Under manual operation of t h e h e a t e r ,

however, some d i f f i c u l t y was experienced i n a d j u s t i n g t h e f u e l r e g u l a t o r t o give t h e proper c o n t r o l p o i n t a i r temperat~xre a t

a l l times, Considerable judgment had t o be exercised i n a d j u s t i n g

t h e s e t t i n g f o r t h 3 n i g h t period, t a k i n g i n t o account t h e e x i s t i n g

c o n t r o l p o i n t temperatwe and v~fhether it required r a i s i n g o r

lowering, and alloming f o r any weather change t h a t might be

expected t o occur d w i n g t h e n i g h t . It i s n o t s u r p r i s i n g

t h e r e f o r e t h a t on some occasions under manual c o n t r o l t h e

e a r l y morning temperature a t t'ne c o n t r o l point was considerably

higher o r lower t h a n t h e temperature c a l l e d f o r i n t h e t r i a l

schedule,

When t h e h e a t e r was

under

t h e r m o s t a t i c c o n t r o l , with

t h e themnostat l o c a t e d a t t h e c o n t r o l p o i n t and w i t h s e t t i n g d i f f i c u l t i e s of manual operation eliminated, t h e a i r

temperature a t t h e c o n t r o l poinit remained r e l a t i v e l y c o n s t a n t , depar-tjng Prom t h e d e s i r e d temperatuxe by no more than about

t7vo degrees, One necessary precaution, however, was t o ad j u s t

t h e "high-fire" s e t t i ~ g s u f f i c i e n t l y h i g h -to t a k e carc of t h e

maximum h e a t demand.

Another d i f f i c u l t y encountered under b o t h t h e r m o s t a t i c and manxal operation was t h a t i n m i l a e r weather t h e flame v~ould tend t o go out on very low f u e l s e t t i n g , r e s u l t i n g i n

considerably reduced a i r temperature, e s p e c i a l l y during t h e n i g h t period vihen t h e heate.- was unattended-, Before r e l i g h t i n g t h e h e a t e r t h e o p e r a t o r was oblLged t o d r a i n most of t h e accumulated f u e l

from t h e p o t ,

A t very loo^ f u e l s e t t i n g t h e reduced combustion

e f f i c i e n c y was accompanied by a grzdual s o o t i n g up of t h e h e a t e r

and flue-pipe

--

2 c h a r a c t e r i s t i c o f most p ~ t - ~ c y p e space h e a t e r s

--

and by t h e middle of t h e t r i a l s e r i e s t h e accumulation mas

s u f f i c i e n t t o warrant pzm'ial dismantling and complete c l e a n i n g

of t h e h e a t e r and f l u e - p i p e , By t h e end of t h e s e r i e s t h e

combustion s u r f a c e s were again coated t o t h e p o i n t vihere c l e a n i n g was advisable,

( e ) V e n t i l a t i o n System Perf omnance

The a r r ~ n g e m e n t f o r v e n t i l a t i n g t h e h u t , c o n s i s t i n g

of t h e roof vent opening around t h e f l u e - p i p e o u t l e t and t h e small f l o o r opening below t h e h e a t e r , was adequate f o r p r o p e r v e n t i l a t i o n under t h e conditions of occupancy of t h e t r i a l s even i n t h e m i l d e s t w i n t e r weather,