temperature analysis for earth air heat exchanger

Temperature analysis for Earth air heat exchanger

Baljit Singh #1, Arun Kumar Asati *2 Rakesh Kumar#3 #1Ph.D Research Scholar, Department of Mechanical Engineering IKGPTU Kapurthala, Punjab, India.

#3IET Bhaddal, Ropar Punjab, India 1 [email protected] [email protected]

*Department of Mechnaical Engineering, SBSSTC, Ferozepur, Punjab, India. SBSSTC, Ferozepur, Punjab, India.

2 [email protected]

Abstract—Now a days save electricity is major concern for societal needs. Various Conventional methods used for to save environment. To make comfort environment many techniques used like thermal comfort. The use of geothermal energy is the best way to make environment healthy for mankind and to reduce the demand of electricity which is increasing day by day. The Earth Air Heat Exchanger system is a best passive technology to the use of geothermal energy. The investigation shows the major temperature drop of 8.9 °C corresponding to inlet temperature (Tin) 41.9 °C on date 31 March 2017, minor drop of 1.1 °C corresponding to inlet temperature (Tin) 26.2 °C on date 5 April 2017. In this research paper efforts will be made to study the accomplishment of low cost cooling system for hot-dry climate.

Keyword - Geothermal energy, Passive, climate.

I. INTRODUCTION

This type of heat exchanger is good for making environment comfort for human beings. It uses the undisturbed temperature of earth for cooling the room. The undisturbed temperature remains constant. It consists of group of buried pipes under the earth through which the air passed through a fan or blower. The material of the pipe may be Poly Vinyl Chloride (PVC), Mild Steel and Concrete. The design parameters that impact the evaluation of this system are: pipe depth, pipe length, pipe diameter, air velocity, air flow rate, pipe material, pipe arrangement [1]. In this paper the Earth Air Heat Exchanger (EAHE) system is studied for hot-dry climate. Air-conditioning systems is the largest energy consumer that is the biggest challenge which arisesnow days. This problem can be overcome by the use of ground coupled heat exchanger in air conditioning system [2]. It suitably meets heating and cooling energyloads of a building. Its performance is based uponthe seasonally varying inlet temperature, and out lettemperature which further depends on the groundtemperature [3].

This heat exchanger built by burying in the ground at a particular depth so that the required cooling and heating can be achieved from system. This air is often outside air for ventilation, but also useful for partially or totally managing thermal loads of construction [4]. In present research study efforts will be made to save electricity by proper set-up of EAHE in spite of using other conventional systems in houses.

The climatic conditions and parameters used strongly affect this system. The modifications of the system depend upon the variation in the parameters used [5]. The set up is free from any dust particles enter into the pipe of heat exchanger which block the passage of air through the pipe.

A large amount of the primary energy is consumed by space heating and cooling in buildings/houses. The requirement of huge renewable energy in the building sector and industrial establishments is the demand for sustainable energy and environments. Geothermal energy is one of the renewable energy sources that we utilised for supplying air at low expense of energy and with a low impact on the environment [6]. The utilizing styles and exploring methods are various, geothermal electricity, ground source heat pump, earth to air heat exchanger (EAHE), etc. are the main application measures. Among them, an EAHE has the advantages of simple system, easy implementation and low operation cost [7].

The use of earth as a component of energy system can be accomplished through three primary methods: direct, indirect and isolated. In direct system, the building is in contact with the earth through the pipes and fresh air form the environment maintains the comfort temperature. In the indirect system, the building interior is cooled by a low cost cooling system or by an earth air tunnel heat exchanger. The isolated system uses the geothermal temperature of earth to enhance the effectiveness of a heat pump by moderating temperatures [8].

The ground temperatures at several depths can be measured, the overall heat transfer coefficient (overall HTC) can be determined; the heat exchange rate quantified. The HGHE consists of 50 m of length buried at 1 m of depth. The energy and exergy analysis of horizontal ground heat exchanger (HGHE) for hot climatic conditions can be determined [9]. The objective of this study is to found a low cost cooling system with the help of this passive method of cooling for ho-dry climate.

ISSN (Print) : 2319-8613 ISSN (Online) : 0975-4024 Baljit Singh et al. / International Journal of Engineering and Technology (IJET)

DOI: 10.21817/ijet/2017/v9i5/170905188 Vol 9 No 5 Oct-Nov 2017 3958

II. EXPERIMENTAL SET-UP AND INSTRUMENTATIONS

It consists of burial concrete pipe of diameter 0.224 m and is buried in the soil at a distance of 1.5 m. The one end of buried pipe is open to the fields and other end is in the room for testing. A blower is connected to the open end of pipes which deliever air to the room for study. The temperature will be measured with the help RTDs of 0.5°C accuracy and least count 0.1°C, range 0-100°C. The RTDs are connected at two different points. One at the inlet to the pipe and other is at the outlet of the pipe. The arrangement of different instruments used for the investigation of the complete system shown in fig 1.

Fig 1.Schematic Diagram of the experimental set-up

III. METHODOLOGY

The EAHE system is switch on and air is flows through the pipes from inlet to outlet from time 7.30 am to 4.00 pm on eight days i.e 29 March 2017 to 5 April 2017. The temperature reading is noted for every half hour. The dry bulb temperature is noted at two points. The buried pipes and temperature indicators are shown in Fig 2.

Fig 2.the buried pipes and temperature indicator used for study.

IV. RESULTS & DISCUSSIONS

A. EFFECT OF TEMPERATURE

In the study of earth air heat exchanger temperature difference between the inlet temperature (Tin) and outlet temperature (Tout) plays an important role. The temperature drop of 2.1 °C is observed at 8.00 am which is caused by minor difference in inlet temperature and soil temperature. The inlet temperature line rapidly goes on increasing after 9.00 am due to rise in Tin temperature from value 30.6 °C to 32.3 °C. The drop of only 0.2 °C is available from time 11.00 am to 11.30 pm which is because of less heat transfer between air and soil at that time. The major drop of temperature is 7.4 °C experienced after 1.30 pm because of excess rise in Tin to value 36.4 °C. The maximum temperature drop is available because of maximum difference in inlet temperature and soil temperature which increasing the rate of heat transfers from air in the pipe and the soil. The lines of temperatures Tin and Tout come closer and closer after 3.00 pm and the fall is equal to 5.4 °C due to decrease in inlet temperature and undisturbed temperature of earth. The undisturbed temperature of the earth is that temperature which remains almost constant throughout the year.



The dropThe fall temperatu°C of theof 2:00 pmaximumshows thsets in ev

The inletat that timoutdoor ctemperatuMinimumand the presistance

p of temperatuof temperaturure 36.3 °C at

e summer daypm is 8.1 °C. Tm heat transfehat difference vening. Also d

t temperature me and fall isclimatic condure of environ

m temperaturepipe surface ie.

Fig

ure is low aftre is constant t that time. A. Therefore froTherefore thiser depends upis reducing af

difference in te

Fig

line after 10.3s equal to 5.5ditions. The Tnment. Maxime difference atis calculated

g 3.Variation of ti

er 8.30 am caand equal to

As we know thom the figures study is compon the differefter 2.00 pm aemperature ob

g 4.Variation of ti

30 suddenly b °C. The perf

Tin curve of temum temperatt the time 8.0using the gen

me vs. temperatu

aused by hot 7.4 °C from

he maximum o 4 it is found

mpletely validaence of two tas the environmbserved at the

me vs. temperatu

ends downwaformance of eemperature exture difference00 am is 2.5 °neral heat tran

ure on 29 March 2

waves passingtime 1.00 pm

outdoor tempethat the maximating the resuemperatures. ment temperatime of 4.00 p

ure on 30 March 2

ards which is bearth air heat xtends upwarde on this day C. The heat tnsfer equation

2017

g near blowerm to 1.30 pm erature at the tmum drop of lts obtained frThe trends of

ature goes on pm is 6.5 °C.

2017

because of woexchanger is

ds after 12.00 at the time oftransfer at then, assuming t

r during mornthis is due totime of 2:00 ptemperature a

from the experf two lines Ti

decreasing wh

orse climatic cgreatly affectpm because

f 2.00 pm is 8e interface betthat there is n

ning time. o same Tin pm is 36.6 at the time riment the in and Tout hen sun is

conditions ted by the of rise in

8.9 °C and tween soil no contact



The variaFerozepuEAHE reworse enand dropdifferencas shownthe air flo

differencam as scontinuou°C is avadrop of that that timThe inlet6.7 °C wThe drop

ation in two cur. Therefore eveals that thenvironmental cp of temperatuce after the timn in Figure 6. ow direction (

The temperatce (Tin-Tout) ofhown figure usly shows inailable at timehe day is avaime. This maxt temperature

which occurs bp of 5.5 °C is o

Fig

curves of Tin athe inlet tem

e performanceconditions anure varies fromme of 1.30 pm

The temperatu(inside the hea

Fi

ture observatif 2.2 °C is obs

7. The diffencreasing trene 10.30 am belable at 1.30 p

ximum fall of(Tin) of 3.00 p

because of decobserved at th

g 5.Variation of ti

and Tout on thmperature variee of system cand passing awm 5.6 °C to 6

m is 8.2 °C andures of soil, aat exchanger).

ig 6.Variation of t

ions on 2 Apserved becauseerence of inlds with increa

ecause of inletpm is 8.4 °C cf temperature pm shows varcrease in inlet

he time of 4.00

me vs. temperatu

hat day showses and corres

an be improveway of clouds 6.9 °C from 1d minimum temair and heat ex

time vs. temperat

pril 2017 aree of morning tlet temperatuase in environt temperature correspondingobserved due

riation in downt temperature

0 pm.

ure on 31 March 2

s abrupt changsponding outled by making

the temperatu1.00 am to 12mperature difxchanger and

ture on 1 April 20

e shown in fitime at the inlre (Tin) and nment temperis reaches to to maximum

e to excess henward directioto value 37.1

2017

ges caused byet temperatursystem compure after 10.32.00 pm. The fference at the the heat trans

017

igure 7. The let and outlet temperature

ature. The fal35.9 °C at thenvironment

eat transfer beon with tempe1 °C and there

y rain in somere varies. Theletely dust fre0 am changesmaximum tem time 8.00 amfer rate also v

minimum temof the pipe at of tested ro

ll of temperatuhat time. The m

temperature oetween the airerature drop oefore less hea

e areas of e study of ee. Due to s abruptly mperature

m is 2.9 °C vary along

mperature time 8.00 om (Tout) ure of 6.0 maximum of 39.3 °C r and soil. of equal to at transfer.



is suddenoutlet tem33.3 °C icurve is bmaximumconstructconcrete.fall is incthe differand beco

increasinThis is duis observtemperatuand less change ienvironmconsidera

The time vs. nly deflected mperature (Tou

instead of 31.bending to dowm drop of thetion of earth a. The inlet tecreasing continrence in inlet

omes almost co

Figure 9 showng in continue ue morning tim

ved from 9.00 ure is changechange in env

in the inlet ament temperatuably.

Fi

temperature pupwards at 9

ut) is 29.1 °C. .5 °C at 9.00 wnward direc

e day availablair heat exchanemperature reanuously as thetemperature

onstant to valu

Fi

ws the tempemanner. The me and differam to 9.30 ams from 4.4 °Cvironment temand outlet valure of the day

ig 7.Variation of t

plots on date 39.00 am due t

The fall is 1.am. The temp

ction at time 1le at 2.30 pmnger as other raches to 40.3 e day reaches (hot) and soilue 7.5 °C to 7

ig 8.Variation of t

erature variatiminimum temence in soil tem is because oC to 5.4 °C fromperature. Thlues of temp

y is 37.2 °C at

time vs. temperat

3 April 2017 ato rise in inle7 °C more thaperature fall o.30 pm is bec

m is 8.5 °C anresearchers us°C at 3.00 pmto peak heati

l temperature 7.0 °C from tim

time vs. temperat

ions on 4 Apmperature dropemperature anof small rise inom time 10.0

he reading of terature at the

t 2.00 pm. The

ture on 2 April 20

are shown in ft temperaturean 2 April 201of 7.5 °C is obause of cool a

nd increases bsed the PVC pm and correspng of the day.(cold) is incr

me of 3.30 pm

ture on 3 April 20

ril 2017. Thep of 2.3 °C is

nd environmenn environmen0 am to 10.30two temperatue time of 2.0e environment

017

fig 8. The cure (Tin) is 33.3 17 as the envibserved after air prevailing because of usepipes whose cponding fall o. The increasereases. Fall of

m to 4.00 pm.

017

e inlet temperas usually ob

nt temperaturent temperature0 am is due toures Tin and T00 pm is 8.0t conditions a

rve of inlet tem°C and corre

ronment temptime of 12.00around the bloe of concrete

conductivity isobserved is 8.e in heat transf temperature

rature (Tin) onserved at time

e. A small falle of 0.9 °C. Tho same conditTout shows con0 °C as the maffect the EAH

mperature esponding perature is 0 pm. The ower. The pipes for

s less than 1 °C. The fer rate as decreases

n this day e 8.00 am. of 0.3 °C he drop of tion of air nsiderable maximum

HE system



A figureavailableincreasinenvironmtime 12.330.4°C apipes mamoisture temperatu2.00 pm.

The averof averagMarch 20temperatuThe averall other average TThe fall oon 1 Apr°C is 6.1temperatu

10 shows ate is 1.1 °C. Tng in morningment temperatu30 pm to 1.00and correspondaximizing the

through condure rises to 3

rage temperatuge fall vs. no. 017 is equal ture of 27.3 °Cage inlet tempdays. The am

Tin of 37.2 °Cof temperaturril 2017. On 2 1 °C. The aveure is 30.0 °C

Fi

t 8.00 am theThe drop tempg hours, dropure decreases

0 pm which cading maximumair to wall codensation. Th0.4°C only. T

Fig

ure fall vs. noof days provi

to is 5.5 °C wC. The fall ofperature curvemplitude of a

C on 31 marchre decreases by

April 2017 therage inlet tem

C correspondin

ig 9.Variation of t

e inlet tempeperature is 1.9p is rises to from peak ho

aused by worsm fall observe

ontact for comhe 5 April 201The drop decr

g 10.Variation of

o. of days showide more clearwhich is becauf 5.7 °C is obse extends upwaverage inlet h 2017 and coy 0.4 °C due

he average inlemperature 36ng maximum

time vs. temperat

erature (Tin) i9 °C at the ti

maximum vours of the dase climatic coned is 5.7 °C d

mplete heat exc17 is coolest reases as the e

f time vs. tempera

ws in figure 1r and concise use of averagserved on 2nd

ward after 3rd dtemperature rresponding mto decrease inet temperature

6.5 °C which fall than othe

ture on 4 April 20

s 26.2 °C at ime of 8.30 a

value in peakay. Temperatunditions. The due to the air change and, inday as compaenvironment t

ature on 5 April 2

11 from date 2picture of teme Tin temperaday caused by

day which givecurve is max

maximum dropn average Tin te is 35.8 °C anis maximum

er days is 6.5

017

this temperaam. The tempk hours and ure fall of only

maximum vacrashes arounn the summerared to other temperature d

017

29 March to 5mperature variature of 33.8 °y velocity of aes the indicati

ximum this is p of temperattemperature frnd average outhan other da°C which bec

ature the miniperature drop drop decreasy 0.1 °C obseralue of Tin at 2nd constantly r, removal of days because

decreases after

5 April 2017. iations. The d°C air and avair 2.5 m/s onion of warmer

because of mture 6.6 °C onrom 37.2 °C t

utlet temperatuays and averacause of maxi

imum fall is slowly es as the rved from 2.00 pm is inside the excess air e the inlet r the time

The plots drop on 29 erage Tout

n that day. r day from maximum n that day. to 36.1 °C ure is 29.7 age outlet imum rate



of heat tris less asis 5.4 °Ccorresponchanges i

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&Bartaria V.N (2ew” MAY 2016 I(2016), “Experimng (JMSME) p-ISRamana P. V. (2ng Climate Condin, Yu Daihong, Lichanger” Applied H, Boyd TL (2005rem, Kaur Harminvironmental Sus

mi Majdi, Kooli atic condition of

temperature afewer rises inin downward is less and equat transfer rate

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t exchanger bike energy savld of renewab

with the help sPunjab can bte level. The (Tin) 41.9 °C oate 5 April 20

ACKN

Punjab Technations of EartProfessor, Sh

iate professort at every step

, “A Review on4, March 2016.

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2016), “Earth AirIJETT, Volume 3

mental PerformanSSN: 2393-9095;2016), “Experimeition” ISSN: 2455i Haorong (2015)Energy 137 (201

5) “Direct applicander (2015), “A stainability: ConcSami, Farhat Abnorthern Tunisia”

and soil (cold)n average inletdirection on ual to 3.9 °C

e along the pip

e temperature fall

CONCLUSI

brings us that ving, money ible energy ressuch type of sbecome energ

investigationon date 31 M17.

NOWLEDGM

nical Universitth Air Heat Ex

haheed Bhagatr and Head o of my researc

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4(6):691–727. ysis of Earth Air TN: 978-93-83083s of horizontal g

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on 7th day at that day

days and ed that the

th the soil e benefits ciety. The ited in the ble energy of 8.9 °C ponding to

unity to go kind help

pur. I also nt at IET,

Tunnel heat

-0072, DEC

Supply Air

Science and 5, pp 40-44. y Simulation

ty prediction

Tunnel Heat -75-6. ground heat 05.



AUTHOR PROFILE

Baljit Singh is Ph.D Research Scholar, Department of Mechanical Engineering, IKGPTU Kapurthala, Punjab, India. He is working in the department of Mechanical Engineering in SBSSTC, Ferozepur, Punjab,India. He has 8 years of teaching experience. He has specialisation in Material, Coating and Thermal Engineering.

Dr. Arun Kumar Asati is working as Associate Professor at SBSSTC, Ferozepur, Punjab,India. He completed his Ph.D from IIT, Delhi. He has 30 years experience in the field of teaching. He has specialization in thermal engineering. He is very hard working. He has published many research publications in international journals and international conferences.His areas of interests are Heat Transfer, Refrigeration and Air Conditioning, Thermodynamics and Desiccant Cooling.

Dr. Rakesh Kumar is working as Associate Professor and Head of Mechanical Engineering Departmentat IET, Bhaddal, Ropar, Punjab. He completed his Ph.D from IKGPTU, Kapurthala in 2016. He has more than 16 year teaching experience in the field of Mechanical Engineering. His areas of interests are Heat Transfer, Refrigeration and Air Conditioning, Micro tubes and Thermal Engineering. He has published many research papers in international journals and conferences.



temperature analysis for earth air heat exchanger

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