ARK Journal Paper-Exp Setup

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Experimental study of reinforced cement concrete (RCC) residential building roof implanted

with hollow PVC tubes in weatherproof course - A passie cooling methodology

A! Ramesh "umar#$% "C"! Vi&aya'umar% P! riniasan*

1*

Department of Mechanical Engineering, Faculty of Engineering, Erode Builder Educational

Trusts Group of Institutions, Tirupur !" 1#"

$ %i&e'anandha Institute of Engineering and Technology, Tiruchengode !( $#)

!no+ledge Institute of Technology, alem !( )#-

*.uthor for correspondence/ Tel/ 01 "!-- !-$, Email/ endrumramesh2yahoo3com

During the sunny time, the sunlit roof is the most predominant for heat entering into the

room compared to the side+alls of the residential 4uildings3 The solar radiation e5posing time is

more for the top roof surface 6sunlit roof7 and the length and 4readth of the room is &ery large +hen

compared to its roof thic'ness3 Therefore, recent research in&estigations are carried out in the sunlit

roof to reduce the un+anted heat through the roof3 This e5perimental study sho+s that, 8%9 tu4es

em4edded :99 roof reduces the heat transfer across it3 Due to this un+anted heat transmission

reduction, reduce the underneath temperature of the roof and in turn enhances the comfortness in

the room3

"eywords+:esidential 4uilding roof, heat transfer, solar radiation, 8%9 tu4es, 9omfortness

,ntroduction

.ncient people surely found relief from the heat in the landscape and encircling many passi&e

cooling practices li'e, +indo+s, doors, indoor spaces, trees, gardens, +ater around the 4uilding,

high roofs, &entilated roofs, domed and &aulted roofs, etc3, to create comforta4le thermal

en&ironment in the residential 4uildings3 In the modern life due to more density in population, cost

of li&ing and a smaller amount of floor area, the people are li&ing in the cro+ded concrete s'eleton

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houses and are using electricity 6for air to )#>

of primary energy ?1@3 Energy consumption for cooling represents roughly -# > of the total

utiliAation for residential 4uildings ?$@3 The uantity of air


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.ll dimensions are in mm

Fig3 $ chematic diagram of the roofs under in&estigation

,nestigational set up

The scaled model three identical e5perimental cells are fa4ricated +ith steel structures, each

ha&ing dimensions of 1### 5 1### 5 1### mm!for the e5perimental in&estigation purpose3

The :oof 1 is casted 4y means of 4are reinforced cement concrete roof of 1)# mm thic'ness,

:oof $ is laid using :99 +ith +eatherproof course of () mm thic' and :oof ! is laid 4y :99 +ith

8%9 tu4es implanted inside the +eatherproof course3 The 8%9 tu4e is ha&ing inner diameter of )$

mm, +ith !3 mm +all thic'ness and allo+s air to flo+ freely3 The schematic representation of

in&estigational setup design is sho+n in Fig3 $3

Fig3 ! In&estigational 9ell

The e5perimental setup +as made 4y mild steel structure, ele&ated 4y 1)# mm a4o&e the

ground le&el using four metal supports, and co&ered +ith grass stre+ and thermo cool sheet to

reduce and 'eep a+ay from ground radiation3 The Fig3 ! sho+s the e5perimental configuration of

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the test cells3 The sides of the +all are +ell insulated +ith )# mm thic' thermo cool sheets utiliAed

to minimiAe the side+all solar radiation3 The side faces of the roof are coated +ith thermo

insulation paint and co&ered +ith insulation material to a&oid solar radiation through it3

Fig3 - olar radiation in May month

The Fig3 - and Fig3 ) illustrate typical solar radiation and am4ient temperature conditions of

the Tirupur city 6atitude 11# H and ongitude (( E7 for the month of May, +here the

ma5imum intensity of solar radiation sho+ers on roof3

Fig3 ) .m4ient temperature in May month

aterial Properties

The material properties of the :99, eatherproof 9ourse, 8%9 pipe and air are

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Fig3 .nemometer

8latinum resistance :TDs 6:esistance Temperature Detectors7 along +ith data logging system

are used for temperature measurements are sho+n in Fig3 (3 Data are logged once in e&ery fi&e

minutes3 For the measurement of roof top and ceiling temperature, hole is made on 4oth top and

4ottom surface for a4out 1# mm deep and the :TD pro4e is inserted and thermo


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temperature is lesser than roof $ and roof !3 In the 8%9 treated roof, a significant amount of heat

carried a+ay 4y air, +hich is freely flo+ing through the 8%9 pipe, minimiAes the temperature at the

top surface of the roof3 The roof ! temperature at top surface sho+s that 1#3)! #9 and !3#!#9 lesser

than the roof 1 and roof $3

Fig3 1# Bottom surface temperature difference in the roof 1, roof $, and roof !

The 4ottom roof ceiling ma5imum temperature of roof ! is !#3"#9 and the roof 1 and roof $

temperatures are -(31-#9 and !!3-#9 6Fig 1#73 By relating, the performance of 8%9 implanted

roof +as found as 13$)#9 in ceiling temperature than roof 1 and !3#)#9 than roof $3

Fig3 11 :oom air temperature difference in the roof 1, roof $, and roof !

.ir mo&ement is the &ital element for the roof !, +hich implanted +ith hollo+ 8%9 tu4es in

+eatherproof course3 It increases cooling 4y increasing e&aporation rates3 The study undou4tedly

pointing out that addition of +eatherproof course 6roof $7 reduces the heat transmission 4y !3!( #9

+hen compared to 4are reinforced cement concrete 6roof 17 and for roof ! as -3-- #9 6Fig3 1173 The

ma5imum room air temperatures for roof 1, roof $ and roof ! at pea' hour of the day are a4out

!$3$-#9, $"3"(#9 and $(3"##9 respecti&ely3

Fig3 1$ Bare :99 roof surface, 4ottom surface and room temperatures

Fig3 1! eatherproof 9ourse roof surface, 4ottom surface and room temperatures

Fig3 1- 8%9 treated roof surface, 4ottom surface and room temperatures

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The figures 1$, 1! and 1- sho+s the in&estigational measured temperatures of 4are :99 roof,

eatherproof 9ourse laid :99 roof and 8%9 pipe implanted eatherproof 9ourse laid :99 roof3

In field e5perimental in&estigation, 8%9 laid roof sho+s 4etter performance than 89 laid roof3

The unrestricted air flo+ in 8%9 pipe increases the resistance o&er the heat transfer through roof

due to 4eam radiation3

Conclusions

The roof is an important factor of design +hen it comes to conser&ing energy 4ecause this

part of the 4uilding recei&es the ma=ority of the solar radiation and its shading is not simple3

E5perimental in&estigation on 8%9 pipe laid reinforced cement concrete roof has 4een carried out

to e5plore the possi4ilities of human comfort conditions3 The follo+ing are the ma=or conclusions

of the in&estigation under tropical climatic conditions,

i3 The 4are :99 roofs thermal conducti&ity is more and results less thermal resistance, and more

solar radiation penetration inside the room ceiling3

ii3 The +eatherproof course treated :99 roof gi&es little more resistance than 4are :99 roof3

.4out 11> of heat reduction o4tained compared +ith roof 13

iii38%9 tu4es are comparati&ely good thermal insulators, +hich results in pre&ention of e5cess heat

transfer across the roof 6roof !73

i&3 .4out 1-> and -> of heat reduction is attained into the room of roof ! +hen compared to roof 1

and roof $ respecti&ely3

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&3 The uantity of heat entering the room is directly proportional to the difference 4et+een the roof

4ottom surface temperature and the room air temperature3 esser the difference, lo+er is the heat

entering into the room, +hich is prefera4le3 The differences are the largest +ith :99 roof,

moderate +ith 89 roof and the least +ith 8%9 laid roof3

Cence the 8%9 treated roof gi&es t+o times resistance than resistance of 4are :99 roof3 The

8%9 em4edded +eatherproof course roof gi&es more comfort than con&entional 4are :99 roof and

89 laid :99 roof3

References

13 M33 iddament, M3 rme, JEnergy and &entilation, .pplied Thermal Engineering, pp3 11#1

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