600

0

Heat supp I i ed MJ/ day 600 650 0 so 100

I I ' 15 . 655. 8 - . ~

11120 1,.;oo;;;;;,--- ,--~

12 15

12 20

~ 3

; ~ : . ~ 0 3 =--~ e..--:. -~ 0 '.!

housf' ~I ~ i -e.. ~

• house l ~

1------Fig. 8 Amount of heat

supplied by heater per day

opposite in the summer and rge eaves of house M are ·mall thennal mass and small house M and house I, the

t loss from the windows was ~ater led to excessive energy idt:ntial buildings should be

'1ut out direct solar radiation

e heat capacity corresponding laced consideration of solar

utl rs on windows, for cross

~ air-conditioner to conserve

. 115 g Energy Conservation, PP·

\

House with a Solar Syste~n , Proc. of JSES/JWEA Joint

10513

THERMAL EFFECT OF SUNSPACE ON INDOOR ENVIRONMENT OF PASSIVE SOLAR HOUSE:

MEASUREMENT AND COMPUTER SIMULATION

Hiroshi YOSHINO* and Hiroyuki SATO**

*Professor, Department of Architecture, Faculty of Engineering, Tohoku University Aoba, Sendai 980-77, Tel:+81-22-217-7883, Fax:+Sl-22-217-7886

**Design Division, Mitsui Corporation, M.Eng.

ABSTRACT A passive solar house with sunspace made of reinforced concrete was constructed in Sendai, Japan in 1984. One year measurement of room temperatures were recorded. Also, detail measurements have been made during the summer and winter seasons.

Further, calculation of indoor temperature was conducted using response factor methods for studying the thermal effects of the sunspace on the indoor environment. This paper describes the measurement and calculation results.

1. INTRODUCTION

Sunspaces are becoming popular in Japanese houses ro obiain an additional room for ameniry and horticulture. F rom the point of view of thennal comfort , the sunspace can get so much solar r3;diation that in the daytime during the winter, tha1 space is warm and comfortable. However, the sunspace is easily over-heated in the daytime during the summer and becomes too cold in the night during the winter. If thermal mass is insralled in the sunspace, the large fluctuation of room temperature can be reduced by absorbing the heat into the mass during the day and releasing heat during the night.

A reinforced concrete passive solar house with a sunspace was constructed in Sendai, Japan in I 984. One year measurements of room temperatures have recorded and detail measurements have also been made for a week during the summer and winter seasons. Additional indoor temperatures were predicted from the data using the response factor method to study the 1hermal effects of the sunspace and other strategies on the indoor environment. This paper describes the measurement results of the passive solar house and the calculation results on how to improve the indoor environment by the sunspace and the oLher strategies.

2. DESCRIPTION OF THE PASSIVE SOLAR HOUSE

The two-storied passive solar house, which has a large sunspace attached to the southern wall, is made of reinforced concrete furnished with 30 mm glass wool insulation. The first floor plan and the section are shown in, Figures 1 and 2, respectively. Th.e total flo?r area of the house except for rhe sunspace is <tround 250 m2 and the inside arr volume is 700 m3. The sunspace has a floor area of 32 m1 and an inside air volume of 200 m3

• All windows have double glazing (K=2.5 I kcaVm2h°C) and low-E glass is used for the glass wall of the sunspace. The K-value of double glazing with low-E glass is 1.88 ~caVm2h0C.

From measurements, the air change rate for an indoor-outdoor pressure difference of

" r m l>

;>'(

c Cf)

I :I)

0

c ill 0 :J

N

(Jl

N

18,000

Figure 1. First floor plan of the investigated house

50 Pa, is 2.3 times per hour. lt can be sai.d that this house is airtight. The equive lant leakage area of glass walls is 139 cm2•

Jn rhe living room, dining room, study room (2nd floor) and bedroom (2nd floor) air-conditioners (Capacity is 2240 kcaVh for cooling and 3500 kcal/h for heating) are installed. In the living room and hall way, hot water pane l radiators are installed (Capacity is 1980 kcal/h and I 134 kcal/h, re pectively). Electric heat is used in the runing room

Two occupants , a couple. are Uving in thi house. The wife is in the house during rhe day. Table 1 shows the occupant 's behavior related to heating and cooling.

3. MEASUREMENT RESULTS 3.1 Measurement Method and Period Measurement of temperature and hurniruty started on Aug. 23, 1994 using small data loggers connected to sensors . Additional detail temperature measurements were made from July 31 to Aug. 8, 1994 in the summer and from Feb. 1 to 8, 1995 in the winter using the thermocouples and data logger.

3.2 One-Year Measurement

From left side

D?uble 9lazing ·openable window

Siding 12mm Air gap I OOmm lnsula1ion I SOmm

(Glass wool) Concre1e

Figure 2. Section of the investigated house

Table I . Occupant's behaviour Term ~ovmg $ 1ylo

1 Openl"!J w1ruJowc botween sunspace and other roomn oarly 1n lhc morning.

2 Operating uir-condilionors in rooms except for the Jap;,nooo slylo room from morning lo

night. . Summer 3 Shading ttoo wn nl !too windows between

rooms on 2nd-floor ond the sunspace. 4 No shading in lho sunspacc. s Opening windows of su~space from 6 to 21

O'CIOCK 1 Operalin!) pnnul 11on1ors wilh nol waler

during d~ytirno, nnd an olcclric healer only In

Winier the kilchon In lho morning and evening. 2 When II b hot in lho sunspace, occupants

open windowf.i botwoon tho sunspace and other room?. lo htlnkc hot a ir.

Figure 3 shows the profiles of daily mean . temperature and humiruty during one year. The sunspace tempcrnturc decreases wach the outdoor temperature but the temperature difference between them is more rhan IO"C during the ~i.nter. Room temperatures are stable during rhe whole year between ~O ~nd 26"C. Humidity of the outdoor and the sunspace changes day by day but chat of the ms1de rooms is fairly stable around 30% in the winter.

1 .:~ 7 0 1

.Q :o.: t

Figure 3.

3.3 Temper . Figure 4 sho!ture m Sm room and s the temp from A Olar radiation of che ;;~s4 ro 6· 1994. T higher tha/t~ce was alw increased to at of. the oi ma"; a maxi mum ..... mum duri o tb ' no sunshade no e .daytij the sunspace oeven w!1h tho temperature of~~ g:rng the room were stabJ oom occupant:S

0 e. a1 around .

indicated rraion ofair-c1 temperature ~~ ~he q uestio the night time. e bedroom

3.4 Temp F erature in w·

1gure 5 show h mte solar radiation ~ t e tempera to 5, 1995 Tor three days sunspace ch~ he tempera1 outdoor air an!~s greatly wiri the OUld . ISJ010 25oc t oor temp ~n:iperacuresofth erat 1

duung room w e bedroo the record of th ere stable at ar windows betw: oc~u~ant 's be Panel heaters wen ms1de roor occupant~ beh e~e operared a1

~he temperatur:;1or between t\'. U! the daytime thaof the bedroo temperatures of th n the tempen

ose rooms di

eJ house

Section of the investigated house

! . Occupant's behaviour

L1v1119 Sl lo ming '\Vlncows berwccn sunspace and 3f rooms ear1y in the morning Haling air-·~onditioners In rooms except !he Japanese style room trom morning to

it. b I n iding lhe sun al !he windows e wee rns on 2nd-lloor and the sunspace. shading in lhe sunspace. ening windows of su~space from 6 lo 21

ock. c1,.ur.n1 pitn OI noat<.Hs .... '1th hot water . ing day1ime. and an electric heater only tn

kitchen in the morning and evening. ien il is hol in the sunspace, occupants ~n windows between the sunspace and

ier rooms to intake hot n1r.

~mpernmre decreases with l!te v n them is more ch an I 0 C

1c , hole year between 2.0 ~nd ~ y by day uL that of the 111side

Sunspace (2F) Sunspace (1 F)

Mey. Jun. ' Jul ' Aug.

Figure 3. Temperature and humidity profiles for one year

3.3 Temperature in Summer Figure 4 shows the temperature at each room and solar radiatio n for three days from Aug. 4 to 6, 1994. The 1emperarure of the sunspace was alwa ys abo ut 5°C higher than that of the o utdoor air and increased to a maximum of 39°C at the maximum during the daytime because of no sunshade even with the windows of the sunspace open during the daytime. The temperature of the bedroom and the dining room were stable at around 25°C from the occupant's operation of air-conditioners as indicated by the questionnaire. The temperature of the bedroom decreases in the night time.

3.4 Temperature in Winter

Sunspace (2F) Suns pace (1 F)

Ou;~;;;·;;; .. ~~~·:;;; .. ·-- Dining room

. Transmit1ed vortica1 10 Horizontal solar radiation ·solar radiation

Aug.4 Aug.5 Aug.6

Figure 4 . Temperature profiles in summer

c: .Q

"-····- · .. --·· ·· ·· ·~ · · .. ... 2 (Q '5

.1 Horlzonml solar radiation Transmitted 'Jertical 1 ~ -solar radlaUon .,

a

Figure 5 shows the temperature and the solar radiation for three days from Feb. 3 to 5, 1995 . The temperature of the sunspace changes greatly with that of the outdoor air and is 10 to 25°C higher than ·

1 Feb.3 Feb.4 Feb.s

o.l--"""-',...._-.--...-uu.c.__-.-~<!W.Q..._-!,· O en

the outdoor temperature. The Figure 5. Temperature profiles in winter temperatures of the bedroom and the dining room were stable at around 22°C except for the daytime on Feb. 3. On that day the record of the occupant's behavior indicates the panel heater was not operated and the windows between inside rooms and the sunspace were open during the daytime. The panel heaters were operated and the windows were closed on Feb. 4. The difference of occupant's behavior between two days influences the room l'cmperaiure change. Namely, the temperatures of the bedroom and the dining room become about 6 C and 4°C high r in the daytime than the temperatures of those rooms in the early morning_ Howe ver, the temperatures of those rooms did not change on Feb. 4.

,.,., >

N

w

-c ' rn )>

"" c (fl

I :JJ 0

4. EFFECT OF SUNSPACE AND OTHER STRATEGIES BY CALCULATION 4.1 Calculation Method In order to study the effect of tile sunspace and the stra tegies for improvino rhe thermal condition. the calculation has been done using the response factor method for heat transfer witb the multi­room ve nti la ti on cal culatio n model. Figure 6 shows a mode l building for ca lcula1ion which is simplified from the acrua l passive solar house. The mode l building has three rooms, that is the first floor room, the second floor room and the sunspace. Table 2 shows the fundamental condition for calculation. Table 3 shows the conditions for 11 cases.

4.2 Comparison between Measurement and Calculation Figure 7 shows the comparison of temperature between measurement and calculation in two cases of the summer and the winter. As the standard weather data of Sendai is used for calculation, the outdoor temperature and the amount of solar radiation are different from those shown in the measurement. So it is difficult to evaluate the agreement between calculation and measurement. But the characteristics of the profiles of the sunspace and the room temperature are similar between them

Figure 6. Model for calculation

Table 2. Conditions for calculation Structure Reinforced concrete

Sunspace direction The soulh

Total floor area Building: 250m2 I Surispeco: 32m2

Room volume Bulldin11: 763m3/ Sunspace: 205m3

Number ol rooms 3

Number of walls 37

Thermal mass of lumiture 4.SkcaVm""c Effective area of window Bulldlnn 48m' I Sunspaco: 113m'

Details of window Building: Double grazing I Sunspace~ Low·E, Double glazing

Ventilation among each rooms Taking into consideration

Occupnncy. Heat generation Aa:ordlng to living schedule

Wealher Data Slandard weather data 1n Sendai

Table 3. Cases for calculation Cases Condit ion~ lorcalculn1lon

Case1 No sunspace (Summor)

Case2 No sunspace (Winier)

Case3 Sunspoce attached (summer)

Case4 Sunspace attached (Winter)

Winter

Cases lnsut~ting the gloss wall of sunspace during the nl ht

CaseG Openlng windows between sunspace ond rooms a.i da ime

Case 12 Cases + Case6

Case7 Shading the solar radiation into sunspace

Cases Oponlng windows of sunspace from 6 to 21 4.2 Calculation Results 1-- -+o"-•c"""1oc""k;.;..._ _ _ _ _ _ _ _ -1

(l)Effect of sunspace Figure 8 Summar Case9 Opening windows of sunspace all dny shows the calculation results of the C to Case9 + Oponing windows between

nsa suntpaco and rooms lrom 18 to 5 O'cloc~ effect of the sunspace on indoor case11 case7+Case10

temperature in the winter and summer. In the summer, where the suospace is attached to rhe house without sunshade and ventilation, the temperature of the suns pace greatly increases to more than 60°C at the maximum during the daytime and the room temperatures are kept IOOC higher than tb~t of the room temperarure without the sunspace. ln the winter, the room temperatures in

the case of the house with the sunspace are also kept l 3<'C h.igher than that in the case of no sunspace. The sunspace is effective for warming the room in the winter but it causes

•o-,---J a) Calcu

U JO ~ ~ '; i;;J.' :J 20· ·- :r-~"

~ ~ 10 ~ ~ j

f- ' Outdoc

o-

. 10---~----Aug.6

40-:--=--,--! a) Calcul;

l .---. ·W----"

Feb.7

Figure 7. Co1

707', ------

«!~· ,,_. Sunsoa•

e so Room 8 i2F)

~ .:.O· ~oo~. A (i FJ

~ ' -~ ~ io: / - Ou:cc.or E r-r---.-,,, :- -i! '' - - . /-...__..,.

j £.. Room B (2FJ 10J Room A 11F)

0 I .n:;l fr-.._

Aug.7 At

(a) Summe Figure ;

over-heating in the room

(2)Effect of night time irn shows the calculation resu ye.ntilation between the suns is mstalled on the glass wall to 5°C higher than that in C to 2°C higher than that in C

In the case where the inti room, the rise of the sunspac

---r e l for calculation

ons for calculation '1e1nforced concrete

fhe soulh

3u1ldlnq: 250m2 I Sunspaco: 32m2

3ulldJno: 763m3/ Sunspaee: 20Sm'

3

37

~.Skcallm"c 3urld1ng: •am' I Suns~aco: 11Jm2

3uilding: Double grazing I :unspaco: Low·E, Double grazing

r01r\Jng into consideration

~ccocdint to IJvlng schedule

3tandard weather data in Sendai

.ses for calculation ins lor Cl\ll:ulaliori

;p~ce (Summer)

:poco \Wlntoc)

ce attached (summer)

oe attached (Win1or)

1g the glass wall of sunspace during

l windows between sunspace and :da)'.!ime

· Cases

1 the solar radiation into sunspnce

l windows of sunspace lcom 6 to 21

1 windows of sunspaco all day

· Opening wlndows between e and rooms from 18 to 5 O'clock

• Case10

1se without sunshade and s to more than 60°C at the kept 10°C higher than that the room temperatures in

;her than that in the case of in the winter but it causes

40 l a) Calculation

OuidoorAlr

0

Aug.6 Aug.7 Aug.6

(a) Summer 40 ' I a) Calculation Room A(1 F) i

e ~~~ ... r· .. '.:~;~p~c~ .. -.. :: _r (l) ... 0 -t'"-·"' . . \"'" '-·····. •-. ., __ _

2 ; i ~ !Oj Room 8(2F)

~ ...... -....... ~ f- o:~ !

' Ouldoor Air ~ .. --·!C-----'-"------==-==,____:

Feb.7 Feb.8 Feb.7

(b) Winter

Living room (1 F)

r:! (ij 0

I "' ~ . ~ ~ 0

N

lo .§ :c

Aug.7

Feb.8

Figure 7. Comparison between calculation and measurement

···----------~lll/i,- Su~spacej\ L NE

I i ~ t:_ '°! ~Room B (2F) 1 :> c

I -Room A (1F) , Case 3[ o ~ ~1 . "-- I ) ' ~.i ~ ;;; . ~~"-"~--=""'---,-.; ~ ~ ra~ ./'.-Outdoor Air : 3 ;:a

~ :ol~;r'" ~,} - ~ : i - Room A (1F) Case 1 : c::

10 ""I 2 ! .-·ii,:\. .._ .. ..,.. t .§ ~ .,_ _ _, ·- "o r

Aug.7 Aug.8 Feb.7 Feb.8

(a) Summer (b) Winter Figure 8. Calculation with and without sunspace

over-heating in the room

(2)Effect of night time insulation and internal ventilation in the winter Figure 9 shows the calculation results of the effect of the night time insulation and the internal ventilation between the sunspace and the rooms. In the case where the night time insulation is installed on the

0lass walls of the sunspace (Case 5). the sunspace temperature increases

to 5°C higher than that in Case 4 with no insuJ, tion. The room temperature also increases to 2°C higher than that in Ca e 4.

In the c~se where the internal air is naturally ventilated b tw en the sunspace and the room, the nse of the sunspace temperature is controlled and Lh room temperature increases

,, r rn )>

(Cl (Cl --.J

;><: c (./)

:r: :n 0

.,, ' m J>

?< c (/) I ::n 0

a little.

~Cases Case12

~ 0 0

· 10-:-. ----.,..--...,..----,-~

Feb. 2nd 3rd 41h Slh 6ih 71h 81h

~Case12 j Room B (2F)

. ~Cases

1~ : ---Q-; ' I - Case6 •

j = ~o~:~~~ Air ~ - •· · ·~·- ·· ..• r ! . .•.. . • I

Feb . 2nd 3rd 41h 5th 61h 7th 81h

Figure 9. Effect of night insulation and open windows(Winter)

70 . I Sunspace

.G" 60j ~ ' e 1 ~ 50~ C! c. § ·10

~ 301 2:-

Case3 -

8 20?

1 0,~l~~~~-.:,.:=;;.~~ Aug. 2nd 3rd 41h Slh 6th 7th Bin

! Room B (2F)

Case3

Casa7

Aug 2nd 3rd 4th 5th 6th 7th Bth

Figure 10. Effect of shading and open windows(Summer)

In the combination(Case 12) of Case 5 and Case 6, the room temperature increases to 4°C higher than that in Case 4.

(3)Effect of sunshade and night time ventilation in the summer Figure 10 shows the calculation results of the effect of the sunshade and night time ventilation. In the case where the sunspace is installed with the ·sunshade (Case 7), the sunspace temperature decrease remarkably and the room temperature also decreases. When the sunspace is naturally ventilated through open windows on all days, the sunspace temperature is close to the outdoor temperature and the room temperature decreases by 3°C. In addition, when the room is naturally ventilated through the open windows, both the sunspace temperature and the room temperature are close to the outdoor temperature.

5. CONCLUSIONS Room temperatures of a passive solar house with sunspace, which is made of conc:-ete with thich insulation, were measured for one year. The room temperature was stable due to the heavy mass during the whole year and the sunspace temperature was influenced greatly by the solar radiation and the natural ventilation.

Calculation results on the effect of the sunspace and the several strategies on ~he room temperature and the sunspace temperature show chat the sunspace is very effe~nve for the room temperature rise in the winter and the night time insulation is especially effective. It is important to install the sunshade and to open windows for ventilation. These effects on indoor temperatures could be estimated by the calculation.

THE I.\1PAC

ABSTR-\CT The imp dwelling has raised the ii colour influences the ther have been undertaken by to the sun and many papc

computer simulations un ci walls and roof of an unins Central Australia . The late NatHERS is used for the \

I. INTRODUCTION

Early work by Olgyayli/ illL irradiance on surface.\ of di early as the 1970s and sinct potential value one way or i similar name) fiiJ was marke1

farm houses and similar bui l type products lhal dispfay si cl1e general misunder. tandin · ~eating effects and in regard' m the community that such r, actually "shade che building

2. THE TEST BUILDIJI

The house being simulated in x l 8m with long facade facing slab on ground floor and full c distributed in proportion to !:he