thermal behaviour analysis and cost-saving opportunities

Research ArticleThermal Behaviour Analysis and Cost-Saving Opportunities ofPCM-Integrated Terracotta Brick Buildings

A Chelliah 1 Shaik Saboor 1 Aritra Ghosh 234 and Karolos J Kontoleon 5

1School of Mechanical Engineering Vellore Institute of Technology Vellore - 632014 Tamil Nadu India2Environment and Sustainability Institute University of Exeter Penryn Cornwall TR10 9FE UK3College of Engineering Mathematics and Physical Sciences Renewable Energy University of Exeter PenrynCornwall TR10 9FE UK4Renewable Energy Stella Turk Building University of Exeter Penryn Cornwall TR10 9FE UK5Department of Civil Engineering Aristotle University of 2essaloniki University Campus Gr 54124 2essaloniki Greece

Correspondence should be addressed to Shaik Saboor saboornitkgmailcom

Received 17 October 2020 Revised 3 January 2021 Accepted 23 January 2021 Published 8 February 2021

Academic Editor Loke Foong

Copyright copy 2021 A Chelliah et al (is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Buildings contribute greatly to global energy use and consumption (e energy consumption of buildings is significant due to theintegration of heating ventilation and cooling systems Evidently the utilization of phase change materials (PCMs) in buildingdesign can adequately reduce air-conditioning costs of buildings by diminishing external heat gains and losses Moreover theadoption of natural eco-friendly and cost-effective materials such as terracotta bricks can be valuable from an environmentalpoint of view (is paper intends to assess the air-conditioning cost-saving potential of several PCM stuffed terracotta brickconfigurations In that respect the encapsulated PCMs were filled in the hollows of terracotta bricks For the aims of this study fivedifferent types of PCMs were considered in relation to the thermophysical properties of their solid and liquid state (OM18organic mixture HS22 hydrated salt OM29 OM32 and OM37) In addition three PCM-stuffed terracotta brick configurationswere examined with reference to the number of the PCM layers (PCMTB-A with one PCM layer PCMTB-B with two PCM layersand PCMTB-C with three PCM layers)(erefore fifteen PCM-stuffed terracotta brick configurations were analysed numericallyrelated to environmental conditions that refer to two different scenarios in India (hot dry and composite climates) Results haveunveiled that the OM32 PCM assemblies have shown better thermoeconomic performance compared to the other types of PCMWith respect to the most advantageous number of PCM layers the evidence of this analysis has exposed that the PCMTB-C casehas shown the highest annual air-conditioning cost-savings and the highest yearly carbon emission mitigations in both climates(Ahmedabad and Lucknow) In hot-dry climates the PCMTB-C with OM32 PCM exhibited the highest annual air-conditioningcost-saving ($ 747) the highest annual carbon emission mitigation (143 tonkWh) and the moderate payback period (225 years)compared to the other cases To conclude the findings of this study suggest a suitable way to improve the decision-making processof building design while bridging the performance gap in terms of energy efficiency and sustainability

1 Introduction

Climate change and environmental degradation pose afundamental threat to mankind Commercial and residentialbuildings require a large amount of energy for heatingventilation and cooling systems while they are also re-sponsible for global warming and depletion of nonrenewablefossil fuels In developing countries like India the con-struction sector is growing rapidly due to economic progress

and the growth of urban communities Buildings constituteabout 40 of global consumption of electricity with resi-dential buildings accounting for three-quarters of the overallenergy consumption and one-third of world GHG emissions[1] Many countries have implemented policies in place toimprove energy efficiency in buildings by ameliorating theeffects of climate change People spend over 90 of theirtime in buildings by paying special attention to a safe cleanand comfortable indoor environment [2]

HindawiAdvances in Civil EngineeringVolume 2021 Article ID 6670930 15 pageshttpsdoiorg10115520216670930

(e traditional means of building thermal conveniencesare mechanical air-conditioning systems that are energy-intensive and detrimental to the environment In this regardenergy-efficient and environmentally friendly techniquesapplied to boost thermal comfort at a zero or low powerconsumption are passive heating and cooling systems [3 4]Towards this goal terracotta bricks that are made of firedclay and have a good density which can provide a fairthermal resistance to building envelopes can be considered

(ermal energy storage by using PCMs is a tolerablepassive cooling approach to moderate heat flows throughbuilding envelopes PCMs can absorb a significant amountof heat during themelting stage (from solid to liquid) as wellas they can release the absorbed heat during the solidifi-cation stage (from liquid to solid) [5] (e ability of PCMs toprovide high energy storage and their characteristics toretain thermal storage at a constant temperature make theirutilization attractive for several building applications [6] Asit is widely known PCMs are commonly categorized asorganic inorganic and eutectic while they should havecertain characteristics such as a nontoxic and noncorrosivebehaviour a suitable thermal conductivity a desirable latentheat and a low cost to attain the fundamental goal of energyefficiency sustainably [7] Organic PCMs mostly shownoncorrosive properties and congruent melting points Inaddition to that the melting point and heat of the fusion ofcertain organic PCMs are suitable for the coolingheating ofbuildings [7] (e method to embed PCMs in the encap-sulation material with a scale exceeding 5mm is calledmacroencapsulation of PCMs while the shape of the shellcan vary (cylinders tubes cubes sticks etc) Macro-encapsulated PCMs can be used in any type size and di-mension of the building envelope [8] An active system withPCMs has a separate storage unit within the building to besettled which is considered to be a demerit for the end-users(e main benefit of incorporating PCMs into buildingmaterials is that less space is required while they can beformulated with a certain behavioural pattern at the veryearly stages of building construction [9] In the literaturevarious shell materials having the potential for thermalenergy storage at high temperatures are examined [10]Moreover several studies reviewed and addressed thethermal efficiency of PCM-integrated buildings as wallboardconfigurations assisted by the operation of the HVAC unit[11ndash18] PCM wallboards in buildings have recorded anadvantageous reduction of the decrement factor and in-crease of the time lag as regards the propagation of a pe-riodic heatwave [19ndash22] Zhou et al analytically investigateda ventilated Trombe wall integrated with double PCMwallboard (Inside and outside) and reported the energystorage and release efficiency of 202 (exterior) and 2025(interior) at the optimum PCM thicknesses (8mm for ex-terior and 28mm for interior) [23]

Yoon et al [24] experimentally studied a scaled model ofa PCM integrated cool roof system and reported a betterperformance for the RT44 PCM assembly for a white roof incomparison with the Bio 26PCM assembly for a brown roofJin et al [25] conducted the experiments and reported thatthe placement of the PCMpouch at a distance of (15) L from

the interior wall surface improves the overall thermalcomfort conditions Tunccedilbilek et al [26] conducted nu-merical simulation on PCM-integrated office building andreported energy savings of up to 128 with PCM of 23mmthickness located at the inner side of the wall A review of theuse of macroencapsulated PCMs for various building en-closures was presented in detail [27] (e thermal efficiencyof a concrete wall integrated with PCMs was analysed nu-merically by Lie et al As seen the incorporation of a 10mmthick PCM layer in a vertical wall leads to approximately20ndash30 reduction of heat gains through buildings located inhot tropical climates [28] (e thermal performance of thePCM integrated brick was numerically investigated byTunccedilbilek et al [29] and they reported the optimum PCMrsquosmelting temperatures as 18degC and 26degC respectively forwinter and summer seasons

(e PCM thermal shield position of a building model wasexperimentally investigated and optimized by Lee et al (eresults exposed the optimal location of PCM layers from theinner surface for various wall orientations [30] (e PCMimpact on building energy consumption was simulated forone whole year in five different cities in China by using EnergyPlus Results have underlined a significant energy saving inbuildings integrated with PCMs [31] PCM integration inbuildings was also modelled and simulated in terms of energydemands by Yun et al [32] Results have indicated a re-duction in cooling cost by 748 while a six yearsrsquo paybackperiod was estimated A building model integrated withPCMs for economic analysis was carried out with Energy Plussoftware by Solgi et al as seen the consideration of PCMs inbuildings lowered the energy requirements for certain ther-mal comfort requirements although it is not rational from aneconomical point of view in Iran due to the high cost of PCMsand the low costs of electricity [33]

(e literature revealed that there is no significant infor-mation on the air-conditioning cost-saving potential carbonemission mitigation and payback period by adopting PCMstuffed terracotta bricks in buildings In this respect the currentstudy aims to analyze numerically three different configura-tions of PCM stuffed terracotta bricks in addition five differenttypes of PCMs such as OM18 HS22 OM29 OM32 andOM37 were assessed for two different scenarios in India (hotdry and composite climates) (e thermophysical properties ofthe assumed PCMs were measured experimentally for bothsolid and liquid phases (is paper explores the unsteadythermal characteristics of PCM stuffed terracotta bricks andutilizes an unsteady thermal transmittance methodology todetermine the air-conditioning cost-saving within buildings(is paper also presents themitigation of carbon emissions andthe resulted payback periods for all analysed PCM stuffedterracotta brick buildings(e findings of this study help in thedesign of energy-efficient buildings with PCM integratedterracotta bricks

2 Materials and Methods

21 Materials (e terracotta bricks are natural materialsmade of clay that shows eco-friendly behaviour (e ter-racotta bricks are moulded with hollows to accommodate

2 Advances in Civil Engineering

PCMs while they are fired at 1000ndash1200degC for four hours toobtain certain strength after firing they may obtain acompressive strength of more than 35Nmm2 Moreoverthe terracotta bricks are lighter than the conventional bricksshowing an absorption capacity that ranges within 15ndash20In this work solid and hollow terracotta bricks were con-sidered and the hollows of the terracotta bricks were stuffedwith various commercially available PCM materials (eanalysed PCMs refer to HS22 (hydrated salt) OM18 OM29OM32 and OM37 (organic mixtures) to accomplish thethermoeconomic analysis (e number of the above-mentioned abbreviations illustrates the melting temperaturevalue of each PCM

22 Experimental Methodology (ermophysical propertiesof terracotta bricks (in solid-state) and PCMs (in solid andliquid state) were measured by using an experimental setupas illustrated in Figure 1 (e viscometer consists of coolingand heating elements to cool and heat PCMs when mea-suring thermal conductivity for both solid and liquid statesWith stability ranging up to plusmn004degC the system has atemperature range within minus20degC to 170degC In that respectthe appropriate temperature has been set by using the digitalreading display It consists of a bath tank that heats or coolswater to an appropriate temperature PCMs were sur-rounded externally around the cup by hot or cold water(e hot or cold water was transferred externally from thebath tank to the measuring system by a close -loop PCMssuch as OM18 HS22 and OM29 are cooled in the vis-cometer when calculating their thermal conductivity with alow freezing point below the atmospheric temperature at thesolid-state On the other hand PCMs such as OM32 andOM37 are easily melted above the air temperature due tothis PCMs were heated in the viscometer to test their liquidthermal conductivity

(e KD2 thermal property analyser (hot wire probemethod) was used to measure the thermal conductivity ofPCMs according to the ASTM standard [34 35] It consists of acable a probe and a monitor to display the related data (ereare two pins on the probe the first one is used as a heatingsource by electric pulse while the second one acts as a receiverPins have a diameter of 13mm and a length of 3 cm with adistance of 6mm to each other(e thermal conductivity of thesolid and liquid states of the PCMs is determined by theresulted temperatures through the time domain (e thermalconductivity in the range of 002W(mmiddotK) to 200W(mmiddotK) canbe determined with an accuracy of plusmn10 (e volumetricspecific heat can also be determined in the range of 050 to400MJ(m3middotK) with an accuracy of plusmn10

(e densities of PCMs were measured with a plusmn 1accuracy by applying a specific gravity bottle process (evolume of the PCM in the liquid state was measured in thecontainer and its weight was measured in the weighingmachine (e differences between the weight of the bottleand the weight of the bottle with the PCMprovide the PCMrsquosweight in the liquid state (e density the weight and thevolume of the liquid PCM were measured by the specificgravity Nevertheless uncertainties were noted for each

PCM with reference to the evaluation of their thermalconductivity and specific heat [36] Table 1 shows thethermal conductivity and specific heat values of the plasterthe terracotta brick and the studied PCMs on both solid andliquid states (with uncertainties) (e phase transitiontemperatures of PCMs were measured using differentialscanning calorimetry [37 38] and are presented in Table 1

23 Design Methodology (e outline of analysed terracottabricks and their corresponding dimensions is depicted inFigure 2

(i) Figures 2(a) and 2(b) illustrate the design of a solidterracotta brick size of 029m longtimes 014mwidetimes 009m high

(ii) Figures 2(c) and 2(d) show the design of a terracottabrick integrated with one PCM layer (PCMTB-A)

(iii) Figures 2(e) and 2(f) show the design of a terracottabrick integrated with two PCM layers (PCMTB-B)

(iv) Figures 2(g) and 2(h) show the design of a terra-cotta brick integrated with three PCM layers(PCMTB-C)

Each PCM layer within the terracotta brick is of the size029 mtimes 006 mtimes 001m Figure 3(a) shows the cube-sha-ped building model (300 mtimes 300 mtimes 300m) consideredfor the objectives of this work (e terracotta bricks are laidin and bound together with plaster accordingly the bondbetween bricks and plaster is equal to 00125m Further-more the thickness of the conventional reinforced cementconcrete (RCC) roof is 015m while as seen in Figure 3(b)both sides of its structure are covered with a plaster of00125m

24 AnalyticalMethodology As it is well known the coolingloads through building envelopes can be diminished byadjusting their thermal mass as well as by increasing theirthermal resistance PCM stuffed terracotta bricks can sig-nificantly improve the thermal mass and thermal resistanceof building structure

(e steady-state transmittance (Us) relies exclusively onthe thermal conductivity of the involved materials (ere-fore a steady-state transmittance signifies only the thermalresistance On the contrary an unsteady-state transmittance

Figure 1 Experimental setup with viscometer and KD2 pro-thermal property analyser

Advances in Civil Engineering 3

Table 1 (ermophysical properties of studied building materials

Phasetransitionrange

SolidPCMtemp

k (W(mmiddotK)) Liquid PCM temp Cp (kJ(kgmiddotK)) ρ (kgm3)

PCM (degC) (degC) Solid Liquid (degC) Solid Liquid Solid LiquidOM18 14ndash20 14 0182plusmn 0002 0176plusmn 0003 28 293plusmn 002 270plusmn 002 907plusmn 6 871plusmn 5HS22 18ndash28 15 114plusmn 0001 057plusmn 0005 28 228plusmn 006 253plusmn 003 1651plusmn 3 1556plusmn 4OM29 24ndash33 20 0293plusmn 0004 0173plusmn 0007 33 233plusmn 002 272plusmn 001 976plusmn 5 880plusmn 3OM32 28ndash38 28 0219plusmn 0002 0145plusmn 0002 40 313plusmn 001 282plusmn 002 926plusmn 4 875plusmn 2OM37 33ndash40 33 017plusmn 0003 014plusmn 0002 45 256plusmn 004 263plusmn 002 974plusmn 2 865plusmn 3Plaster mdash 0721plusmn 0005 mdash mdash 176plusmn 004 mdash 840plusmn 3 mdashTerracottabrick mdash 062plusmn 0004 mdash mdash 0816plusmn 004 mdash 1950plusmn 5 mdash

029m 014m

009m

(a)

P TB P

00125P + 014TB + 0125P

(b)

PCM

(c)

P TBTB PPCM

0125P + 0065TB + 001PCM + 0065TB + 00125P

(d)

(e)

P PTB TB TBPCM

PCM

00125P + 004TB + 001PCM + 004TB +001PCM + 004TB + 00125P

(f )

(g)

PTBTB TB TBPCM

PCM

PCM

P

0125P + 0028TB + 001PCM + 0027 + 001PCM+ 0027TB + 001PCM + 0028TB + 00125P

(h)

Figure 2 Outline of assumed terracotta brick geometries (a)-(b) solid terracotta brick (c)-(d) terracotta brick with one PCM layer (e)-(f )terracotta brick with two PCM layers (g)-(h) terracotta brick with three PCM layers


(Ut) is the measure of both the thermal resistance and thethermal mass of building elements (walls slabs roofs etc)as it simultaneously takes into account the thermal con-ductivity the specific heat capacity and the density underperiodic thermal conditions A lower unsteady-state thermaltransmittance value signifies a higher thermal resistance andthermal mass [39ndash43] (e steady-state thermal transmit-tance Us indicates the heat transfer rate through a buildingconfiguration A lower value of steady-state transmittanceimplies better thermal resistance of its assembly It is givenby the following equation

UTB+PCMs 1ho

+Xp

kp

+Xtb

kcb+

Xpcm

kpcm+1hi

1113888 1113889

minus1

(1)

To determine the unsteady-state transmittance the at-tenuation factor (decrement factor) and the time delay (timelag) of masonry walls settled with solid terracotta bricks andPCM stuffed terracotta bricks a one-dimensional heatdiffusion equation was solved by applying the admittancemethod to compute unsteady parameters

z2T

zx2

1α

zT

zτ

Te

qe

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦

cosh(m + im)(sinh(m + im))

c

c sinh(m + im) cosh(m + im)

⎡⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎣

⎤⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎦

Ti

qi

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦

(2)

where Te is the cyclic temperature qe is the cyclic heat flux αindicates the thermal diffusivity (α kρCp) andm signifiesthe cyclic thickness (m xmiddotz) In addition x specifies theelement thickness while z refers to the finite thickness of theelement (z

ρcpkn

1113969) and n is the cyclic period

(e characteristic admittance of an element is derived by(c)

j

11139682πkρcpn and therefore it is

f1 f2

f3 f1

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦

b1 + ib2b3 + ib4( 1113857

c

c minusb4 + ib3( 1113857 b1 + ib2

⎡⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎣

⎤⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎦

b1 coshm cosm

b2 sinhm sinm

b3 (coshm sinm + sinh n cosm)12

radic1113888 1113889

b4 (coshm sinm + sinhm cosm)12

radic1113888 1113889

(3)

Moreover it is(ematrices for internal and external surface resistances

are given by

rst 1 h

minus1i

0 1⎡⎣ ⎤⎦ middot rso

1 hminus1o

0 1⎡⎣ ⎤⎦ (4)

(e transmission matrix for conventional walls withconvection resistance is given by

Te

qe

1113890 1113891 1 h

minus1i

0 1⎡⎣ ⎤⎦

m1 m2

m3 m11113890 1113891

n1 n2

n3 n11113890 1113891

1 hminus1o

0 1⎡⎣ ⎤⎦

Ti

qi

1113890 1113891

(5)

where m and n indicate different building materials

Te

qe

1113890 1113891 A1 A2

A3 A41113890 1113891

Ti

qi

1113890 1113891 (6)

(e unsteady-state transmittance Ut is the heat flow atthe inner surface when the exterior surface is exposed to aperiodic temperature variation while the room temperatureis maintained at a constant temperature It can be computedby the following equation

3m3m

3m N

W

S

E

(a)

P

RCC

P

(b)

Figure 3 (a) Cube-shaped building model (b) RCC roof configuration


Ut 1

A2

11138681113868111386811138681113868111386811138681113868

11138681113868111386811138681113868111386811138681113868 (7)

(e attenuation of the sinusoidal heatwave through thewallroof is called the decrement factor (f ) or attenuationfactor It is the ratio of the unsteady transmittance to thesteady transmittance

f Ut

Us

(8)

(en again the time lag (φ) specifies the time it takes fora heatwave to propagate from the exterior to the interiorsurface with respect to the temperature peaks Its value isgiven by

φ 12πarctan

im(f)

Re(f)1113888 1113889 (9)

A MATLAB code was developed to compute unsteady-state transmittance decrement factor and time lag of var-ious masonry walls settled with terracotta bricks In a secondstep the determined unsteady-state transmittance was uti-lized to estimate the potential for air-conditioning cost-saving and carbon emission mitigation potential as well asthe payback periods of buildings

25 Cost Assessment Methodology (e temperature differ-ences between the external environment and the constantreference temperature within the internal space of a buildingzone delineate the heating and cooling loads throughbuilding enclosures (e degree-hours approach is a feasiblemethod to compute annual energy usage (e annual energysavings of building envelopes for heating and cooling can beestimated by using heating degree-hours (HDH) and coolingdegree-hours (CDH) According to the ASHRAE require-ments 18degC is assumed as the base temperature for bothcooling and heating of buildings ASHRAE meteorologicaldata have been utilized for cooling and heating degree-hoursin Ahmedabad (2307degN 7263degE) and Lucknow (2675degN8088degE) in India [44] Figure 4 shows the monthly coolingand heating degree-hours for both mentioned cities Table 2shows the elements considered for the correspondingthermoeconomic analysis (e sol-air temperature is thetemperature which gives the combined effect of outdoortemperature distribution and incident solar radiation (eCDH can be computed by multiplying the number ofcooling hours with the difference in sol-air temperature andbase temperature Similarly HDH can be computed bymultiplying the number of heating hours with the differencein sol-air temperature and base temperature as shown inequations (10) and (11) respectively

CDH NC TS minus Tb( 1113857 (10)

HDH NH Tb minus TS( 1113857 (11)

where NC and NH are the number of cooling and heatinghours Tb is the constant-base temperature and Ts is the sol-air temperature

(e thermoeconomic analysis can be performed tocompute parameters such as cooling and heating cost sav-ings (Cc and Ch) total air-conditioning cost-savings (Ct)payback period (PB) and carbon emission mitigation (CM)[45ndash47] (e cooling and heating cost-saving findingsprovide information about the beneficial impact of insertingPCMs in terracotta bricks compared with conventionalsolid terracotta brick assemblies in buildings (ey can becomputed by using the following equations

Cc 10minus 3

CeCDHΔUlt

COP1113888 1113889 (12)

Ch 10minus 3

CnHDHΔUst

η1113888 1113889 (13)

Moreover the total air-conditioning cost savings can beobtained from the following equation

Ct Cc + Ch (14)

It should be noted that Ch and Cc refer to the heating andcooling cost savings while ∆Ut is the difference in unsteady-state thermal transmittance between the solid terracottabrick scenario and the filled with PCMs terracotta brickscenario

Saving of electricity leads to a wanted carbon mitigationeffect (is effect can be obtained from

Mc 10minus 3 ΔUltp1

CDH

COP+ ΔUs

tp2HDH

η1113888 1113889 (15)

where p1 is the mass of carbon emission per unit energyproduction by the coal power plant and p2 is the mass ofcarbon emission per unit energy production by natural gas

Finally the payback period highlights the time it takesfor PCMs to recover the funds invested (the initial invest-ment cost) It is derived by the following equation

pp ln Ci(i minus d)Ct + t11113858 1113859

ln(1 + i)(1 + d) (16)

(e inflation rate (i) and discount rate (d) values areconsidered as per the Indian scenario (is payback periodmethod considers inflation rate and discount rates but itdoes not consider the escalation rate of energy

3 Results and Discussion

31 Unsteady Parameters of Various PCM-Stuffed TerracottaBricks Equations (1) and (7) are applied to assess steady andunsteady transmittances of bricks respectively Figure 5(a)depicts the steady and unsteady transmittances of solid andterracotta bricks stuffed with PCMs From these results it isnoted that the unsteady transmittance is lower than thesteady transmittance for all the studied bricks On the otherhand the unsteady transmittance depends on the funda-mental thermophysical properties of bricks such as thermalconductivity specific heat capacity and density Unsteadytransmittance is the finest measure to assess the thermalmass and thermal resistance of a structure while it allows an


accurate calculation of air-conditioning cost-saving poten-tial of various terracotta bricks stuffed with PCMs As it isalready mentioned a lower value of unsteady transmittanceindicates a better thermal performance of terracotta bricks(in relation to the thermal mass and the thermal resistance)PCMs in the liquid phase provide the least values of steadyand unsteady transmittance compared to the solid phasedue to their superior thermophysical properties in this state

In general amongst all studied terracotta brick configura-tions (TB PCMTB-A PCMTB-B and PCMTB-C) thePCMTB-C configuration has shown the best thermal be-haviour due to its lowest unsteady transmittance valueFurthermore in relation to the optimal PCM (OM18 HS22OM29 OM32 and OM37) it is revealed that the OM32shows the lowest steady and unsteady transmittance values(e order of preference of the examined PCMs from the

14000

12000

10000

8000

6000

4000

2000

0

2000

4000Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

1632

72

3048

792

7056

4056

9744

7968

1171

210

488

1053

610

056

8448 87

84

7536

8424

7920

7416 76

8057

36

4752

2136 23

7621

6

168

2544

4855

2 24 48 4813

44

Ann

ual d

egre

e-ho

urs (

degC-h

ours

)

Ahmedabad-CDHAhmedabad-HDHLucknow-CDHLucknow-HDH

Figure 4 Annual cooling and heating degree-hours in Ahmedabad and Lucknow

Table 2 Elements used for the thermoeconomic analysis

S No Elements Value1 Annual cooling degree-hours (CDH18

oC) (degC-hours) in ahmedabad and lucknow 82440 and 6614

2 Annual heating degree-hours (HDH18oC) (degC-hours) in ahmedabad and lucknow 264 and 4512

3 Outside and inside heat transfer coefficients (ho and hi) (Wm2K) 2500 and 7704 Coefficient of performance (COP) 2505 Unit cost of electricity (Ce) ($kWh) 00826 Unit cost of natural gas (Cn) ($kWh) 00147 Efficiency (η) 0808 Mass of CO2 emission rates per unit usage of electricity (p1) (kgkWh) 098 x 1609 Mass of CO2 emission rates per unit usage of natural gas (p2) (kgkWh) 01810 Material cost of PCMs (Ci) ($kg) COM18 CHS22 COM29 COM32 and COM37 375 126 429 268 and 28611 Inflation rate (i) 7612 Discount rate (d) 66


Steady transmittance (Us) (Wm2K)

Unsteady transmittance (Ut) (Wm2K)

3 2 1 2

3 2 1 2

PCMTB-C(solid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-B(liquid)

PCMTB-A(solid)

PCMTB-A(liquid)

TB

UsUt

145143151159

164137135143144145

15148

15416166

144143

149149

1515515415816

167152151155155165

0770720810820850670640707908

078077084084086

075073077081083086084087087088

083082084085087

OM18OM18HS22HS22

OM29OM29

OM32OM32OM37OM37UtUs

18253

(a)

80

75

70

65

60

45

4000

05

10

15

Tim

e lag

(h)

TB-DFTB-TL

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

Time lag

644 645

646 6

556

52

628 63 635 6

56

48

676

677 679 6

966

91

66 665 6

72 686

68

707 708 711

737

73

685 69 7

05 721

717

056

055

055

054

054

057

055 054 053

054

056 054

053 0

50

52

056 056 053 0

50

53

056 052 0

50

470

49

056 055

054 047

051

44

071

Decrement factor

PCMTB-A(liquid)

TB PCMTB-A(solid)

PCMTB-B(liquid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-C(solid)

80

75

70

65

60

45

4000

05

10

15

Dec

rem

ent f

acto

r

(b)

Figure 5 (ermal characteristics of terracotta bricks integrated with PCMs (a) Steady and unsteady transmittance variations (b) decrementfactor and time lag variations


least steady and unsteady transmittance to the highest steadyand unsteady transmittance is OM32ltOM37ltOM29ltHS22ltOM18

(e decrease of the decrement factor as well as theincrease of the time lag by selecting terracotta brick canaffect substantially the indoor thermal comfort conditions inbuildings in that respect temperature peaks due to theheatwave can be attenuated and shifted from peak hours tononpeak hours To assess the decrement factor and time lagvalues one can apply equations (8) and (9) respectively Toimprove the thermal performance of terracotta brick theattenuation factor should be as low as possible while thetime lag should receive a high value Figure 5(b) shows theattenuation factor and its time lag of various terracottabricks stuffed with PCMs PCMs in the liquid phase lead tothe lowest values of the attenuation factor and the highestvalues of time lag in relation to the solid phase PCMTB-Aand PCMTB-B configurations are designed with one andtwo layers of PCMs respectively (e PCMTB-C is designedwith three layers of PCM and therefore the PCMTB-C offersthe highest thermal mass compared to PCMTB-A and B Asit is expected with regard to all analysed terracotta brickconfigurations (TB PCMTB-A PCMTB-B and PCMTB-C)the PCMTB-C configuration has shown the lowest attenu-ation factor and the highest time lag values due to enhancedthermal mass In addition for the optimal PCM (OM18HS22 OM29 OM32 and OM37) it is exposed that theOM32 shows the lowest attenuation factor and the highesttime lag To conclude the thermal performance of allanalysed terracotta brick walls stuffed with a certain PCM isclarified by fOM32lt fOM37lt fOM29lt fHS22lt fOM18 andφOM32gtφOM37gtφOM29gtφHS22gtφOM18

32 Cooling and Heating Cost saving of Terracotta BrickBuildings Integrated with PCMs Equations (12) and (13) areapplied to compute cooling and heating cost saving ofvarious PCM stuffed terracotta brick buildings compared tosolid terracotta brick buildings Figures 6(a) and 6(b) il-lustrate the cooling and heating cost saving of variousbuildings arranged with masonry walls (solid terracottawalls and terracotta walls integrated with PCMs) inAhmedabad and Lucknow climates

In Ahmedabad terracotta brick wall configurationsPCMTB-A stuffed with a certain PCM of OM18 HS22OM29 OM32 and OM37 have shown a cooling cost savingof $ 5992 $ 6134 $ 6200 $ 6334 and $ 6235 respectivelyLikewise the heating cost saving is $ 01 $ 01 $ 01 $ 011and $ 01 Evidently amongst all examined PCMs in thePCMTB-A assembly the OM32 shows the highest coolingand heating cost saving Furthermore the terracotta brickwall configuration PCMTB-B stuffed with OM32 PCMshows the highest cooling and heating cost saving of $ 6927and $ 011 respectively Similarly with respect to all sim-ulated terracotta brick wall configurations the PCMTB-Cstuffed with OM32 showed the highest cooling and heatingcost saving of $ 7458 and $ 012 respectively

Similarly in Lucknow terracotta brick wall configurationPCMTB-C stuffed with OM32 PCM shows the highest

cooling and heating cost saving of $ 598 and $ 204 re-spectively As seen the cooling cost saving is more evident inAhmedabad than in Lucknow due to its hot-dry climaticconditions Nevertheless the heating cost saving is pre-dominant in Lucknow in comparison to Ahmedabad due toits exposed composite climate

(e most influencing thermal characteristic for en-hancing cooling and heating cost savings is the unsteadytransmittance of PCM integrated terracotta bricks A lowervalue of unsteady transmittance contributes to highercooling and heating cost savings (e best order of PCMs asper the highest cooling and heating cost-saving isOM32gtOM37gtOM29gtHS22gtOM18 (e preferred or-der of PCM stuffed terracotta brick configuration as per thehighest cooling and heating cost-saving is PCMTB-Cgt PCMTB-Bgt PCMTB-A

33 Total Building Air-Conditioning Cost Saving of TerracottaBrick Buildings Integrated with PCMs Equation (14) is usedto estimate the total building air-conditioning cost saving ofterracotta brick buildings integrated with PCMs comparedto conventional terracotta brick buildings Figure 7 showsthe total building air-conditioning cost saving of terracottabrick buildings stuffed with PCMs compared to solid ter-racotta brick buildings in Ahmedabad and Lucknowclimates

In Ahmedabad terracotta brick wall configurationsPCMTB-A stuffed with PCMs of OM18 HS22 OM29OM32 and OM37 have shown an overall total building air-conditioning cost saving of $ 6002 $ 6144 $ 621 $ 6345and $ 6263 respectively Amongst all PCMs in the PCMTB-A the OM32 underlines the highest total building air-conditioning cost saving (e terracotta brick wall config-uration PCMTB-B stuffed with OM32 PCM shows thehighest total building air-conditioning cost saving of $ 694among all examined configuration in this category Inoverall among all assumed terracotta brick wall configu-rations stuffed with PCMs (PCMTB-A PCMTB-B andPCMTB-C) the PCMTB-C configuration with PCM cor-responding to OM32 shows the maximum total building air-conditioning cost saving of $ 747

In Lucknow amongst all the examined terracotta brickwall configurations the PCMTB-C stuffed with OM32 re-veals the highest total building air-conditioning cost savingof $ 619 In Ahmedabad and Lucknow the terracotta brickwall configuration PCMTB-B with OM32 shows a 935increase in total building air-conditioning cost savingcompared to PCMTB-A with OM32 (e terracotta brickwall configuration PCMTB-C with OM32 shows an incre-ment of 1773 in total building air-conditioning cost savingcompared to PCMTB-A with OM32

34 Carbon Emission Mitigation Potential of Terracotta BrickBuildings Integrated with PCMs Equation (15) was used todetermine the carbon emission mitigation of terracotta brickbuildings stuffed with PCMs compared to solid terracottabrick buildings Figure 8 shows the carbon emission


80

75

70

65

60

55

50

5

0

5

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)

Cooling cost savings Ahmedabad

599

2 613

4

62

633

4

625

3

625

3

636

666

7 692

7

676

9

644

6

651

8

709

8

745

8

728

4

01 01 01 011 01 011 01 011 011 011 011 01 011 012 011

Heating cost savings

PCMTB-A PCMTB-B PCMTB-C

OM18 CCSOM18 HCS

HS22 CCSHS22 HCS

OM29 CCSOM29 HCS

OM32 CCSOM32 HCS

OM37 CCSOM37 HCS

PCMTB-C

PCMTB-B

PCMTB-A

P

P P

PP

PTB TB

TB

TBTB

TB

TB

TB

TB

PCM

PCM

PCM

PCM

PCM

PCM

(a)

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)

Cooling cost savings Lucknow

65

60

55

50

45

40

35

30

0

5

10

480

8

492

2

497

4

508

2

501

7

501

7

510

3 534

9 555

8

543

1

517

2

522

9

569

5 598

4

584

5

173

175

177

181

175

181

177

181

194

192

186

179

184

204

194

PCMTB-A PCMTB-B

PCMTB-B

PCMTB-A

PCMTB-C

PCMTB-C


OM18 CCS HS22 CCSHS22 HCSOM18 HCS

OM29 CCS OM32 CCSOM29 HCS OM32 HCS

OM37 CCSOM37 HCS

PP

P P

PP

TB

TB

TB TB TB TB

TB TB

TBPCM

PCM

PCM

PCM

PCM

PCM

(b)

Figure 6 Annual cooling and heating cost of terracotta brick buildings integrated with PCMs (a) Ahmedabad (b) Lucknow


mitigation potential of terracotta brick buildings integratedwith PCMs in Ahmedabad and Lucknow climates

In Ahmedabad terracotta brick wall configurationsPCMTB-A stuffed with PCMs of OM18 HS22 OM29OM32 and OM37 have shown a carbon emission mitigationof 115 tonkWh 117 tonkWh 119 tonkWh 121 tonkWh and 120 tonkWh respectively Amongst all PCMs inthe PCMTB-A assembly the OM32 shows the highestcarbon emission mitigation the findings have led to a 121tonkWh mitigation effect due to the significant air-con-ditioning cost saving for this selection (e terracotta brickwall configuration PCMTB-B stuffed with OM32 shows thehighest carbon emission mitigation of 133 tonkWh amongall studied PCMs Within the framework of all analysedterracotta brick wall configurations stuffed with PCMs(PCMTB-A PCMTB-B and PCMTB-C) the PCMTB-Cconfiguration with PCM corresponding to OM32 shows thehighest carbon emission mitigation of 143 tonkWh

(en again in Lucknow amongst all the terracotta brickwall configurations (PCMTB-A PCMTB-B and PCMTB-C)stuffed with PCMs the PCMTB-C formations with PCMcorresponding to OM32 highlights the highest carbonemission mitigation of 117 tonkWh In Ahmedabad andLucknow the terracotta brick wall configuration PCMTB-Bwith OM32 shows an increment of 935 in carbon emissionmitigation compared to PCMTB-A with OM32 (e ter-racotta brick wall configuration PCMTB-C with OM32shows an increment of 1773 in carbon emission mitiga-tion compared to PCMTB-A with OM32

35 Payback Periods of Terracotta Brick Buildings Integratedwith PCMs Equation (16) was used to calculate the paybackperiod of terracotta brick buildings stuffed with PCMsFigure 9 shows the payback periods of terracotta brickbuildings integrated with PCMs compared to conventionalterracotta bricks in Ahmedabad and Lucknow

In Ahmedabad terracotta brick wall configurationsPCMTB-A stuffed with PCMs of OM18 HS22 OM29OM32 and OM37 have resulted in a payback period of 136years 81 years 15 years 94 years and 10 years respectivelyAmongst all PCMs in the PCMTB-A assembly the HS22shows the least payback period of 81 years followed by 94years for OM32 (e payback periods increase from theconfigurations PCMTB-A to PCMTB-C due to the increasedcost of incorporating PCMs in terracotta bricks Accord-ingly the PCMTB-A and PCMTB-B configurations aremore profitable from an economic point of view while theypresent rational payback periods in contrast to PCMTB-CFor the lower payback periods the following PCMmaterialsare preferred in sequence HS22 OM32 OM37 OM18 andOM29(e preferred sequential order of PCM is the same asmaterial cost sequential order of PCM from low cost to highcost (e material cost of PCM is the most influential pa-rameter in the payback period of PCM integrated terracottabricks From the lowest payback periods perspective theconfigurations PCMTB-A and PCMTB-B are preferred overPCMTB-C

(e results of the above research findings apply to hot-dry and composite climatic conditions (e research can be

80

70

60

50

40

30

40

50

60

70

Tota

l bui

ldin

g ai

r con

ditio

ning

cost

savi

ngs (

$ye

ar)

Ahmedabad

600 614

621 63

4

626

626

637 66

8 694

678

646

653

711 74

7

730

498

510

515

526

519

520

528

553

575 56

2 536

541

588

619 604

Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P TBPCM

PCM

PCM

PCM

PCM

PCM

TB P

TB

TB

TB

TB

P

P

TB

TBTB

P

P

Figure 7 Total building air-conditioning cost saving of terracotta brick buildings integrated with PCMs in Ahmedabad and Lucknow


285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081

136Lucknow Amhedabad

Payback period (years)

OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A

Figure 9 Payback periods of terracotta brick buildings integrated with PCMs in Ahmedabad and Lucknow

150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP

Figure 8 Carbon emission mitigation of terracotta brick buildings integrated with PCMs in Ahmedabad and Lucknow climates


extended to other climatic regions as well Future researchcan be carried out on energy-efficient building envelopesintegrated with various combinations of new PCMs

4 Conclusions

(is work evaluates the unsteady heat transfer character-istics air-conditioning cost-saving carbon emission miti-gation and payback periods of various PCM stuffedterracotta bricks compared to conventional terracotta bricksIn that respect the thermophysical properties of five dif-ferent PCMs (OM18 HS22 OM29 OM32 and OM37) inboth solid and liquid phases were measured (is paperpresents a mathematical model to compute unsteady ther-mal parameters which are further utilized for computing theair-conditioning cost-saving potential of PCM stuffed ter-racotta brick buildings in hot-dry and composite climates ofIndia

(i) (e buildings of PCMTB-C configuration stuffedwith OM32 saves the highest yearly air-condi-tioning costs of $ 7470 and $ 619 respectively inhot-dry and composite climates of India among allthree terracotta brick configurations (PCMTB-A Band C) with five PCMs (OM18 HS22 OM29OM32 and OM37) studied

(ii) (e buildings of PCMTB-C configuration stuffedwith OM32 saves the highest carbon emissionmitigation of 143 tonkWh and 117 tonkWhrespectively in hot-dry and composite climates ofIndia among all three terracotta brick configura-tions (PCMTB-A B and C) with five PCMs (OM18HS22 OM29 OM32 and OM37) studied

(iii) (e steady and unsteady transmittances reducewith the increase in the PCM layers in the terracottabricks PCMTB-C configuration stuffed with OM32PCM gives the least steady and unsteady trans-mittance due to its improved thermal mass andthermal resistance compared to all studied con-figurations with five PCMs

(iv) (e attenuation factor reduces and time lag en-hances with the increase in the PCM layers in theterracotta bricks PCMTB-C configuration stuffedwith OM32 PCM gives the least attenuation factorand the highest time lag due to its improvedthermal mass and thermal resistance compared toall studied configurations with five PCMs

(v) (e best order of PCMs as per the desirable un-steady parameters highest air-conditioning cost-saving highest carbon emission mitigation po-tential is OM32gtOM37gtOM29gtHS22gtOM18(e preferred order of PCM stuffed terracotta brickconfiguration as per the desirable unsteady pa-rameters highest air-conditioning cost-saving andhighest carbon emission mitigation potential isPCMTB-CgtPCMTB-Bgt PCMTB-A

(vi) (e payback period of the building increases withthe increase in the PCM layers in the terracotta

brick PCMTB-A stuffed with HS22 buildings inhot-dry climate shows the least payback period of81 years among all three terracotta brick config-urations (PCMTB-A B and C) with five PCMs(OM18 HS22 OM29 OM32 and OM37) studiedFor the lower payback periods in hot-dry andcomposite climates the following PCM materialsare preferred in sequence HS22 OM32 OM37OM18 and OM29 From the lowest payback pe-riods perspective the configurations PCMTB-Aand PCMTB-B are preferred over PCMTB-C

(vii) It is recommended to use PCMTB-B configurationwith OM32 for buildings to have desirable unsteadyparameters higher air-conditioning cost-savinghigher carbon emission mitigation potential andacceptable payback periods It is not advisable to gofor PCMTB-C configuration due to its long pay-back period of about 20 years

(e results of this study are useful in designing energy-conscious buildings with PCM-integrated terracotta bricks

Nomenclature

Cc Cooling cost saving ($)Ce Unit cost of electricity ($kWh)Ch Heating cost-saving ($)Ci Material cost of PCM ($kg)Cn Unit cost of natural gas ($kWh)Cp Specific heat (kJ(kgmiddotK))Ct Annual air-conditioning cost-saving ($)d Discount rate ()f Decrement factor (-)h Heat transfer coefficient (W(m2middotK))i Inflation rate ()k (ermal conductivity (W(mmiddotK))Mc Mass of CO2 emission reduction (tonkWh)NC Number of cooling hours (h)NH Number of heating hours (h)p1p2

Mass of CO2 emission due to energy production (kgkWh)

Tb Base temperature (degC)Ts Sol air temperature (degC)U (ermal transmittance (W(m2middotK))Ut Unsteady transmittance (W(m2middotK))X Building material thickness (m)

Greek letters

α (ermal diffusivityη Efficiency of natural gas power generationφ Time lag (h)ρ Density (kgm3)

Acronyms

CDH Cooling degree-hours (degC-hours)COP Coefficient of performanceHDH Heating degree-hours (degC-hours)HS Hydrated salt


OM Organic mixtureP PlasterPP Simple payback periodPCM Phase change materialPCMTB PCM-stuffed terracotta brickTB Terracotta brick

Data Availability

(e data used to support the findings of this study are in-cluded within the article

Disclosure

(is research received no specific grant from any fundingagency (publiccommercial)

Conflicts of Interest

(e authors declare that they have no conflicts of interest

References

[1] P Nejat F Jomehzadeh M M Taheri M Gohari andM Z Abd Majid ldquoA global review of energy consumptionCO 2 emissions and policy in the residential sector (with anoverview of the top ten CO 2 emitting countries)rdquo Renewableand Sustainable Energy Reviews vol 43 pp 843ndash862 2015

[2] R Qi L Lu and H Yang ldquoInvestigation on air-conditioningload profile and energy consumption of desiccant coolingsystem for commercial buildings in Hong Kongrdquo Energy andBuildings vol 49 pp 509ndash518 2012

[3] D G L Samuel S M S Nagendra and M P Maiya ldquoPassivealternatives to mechanical air conditioning of building areviewrdquo Building and Environment vol 66 pp 54ndash64 2013

[4] K J Kontoleon ldquoGlazing solar heat gain analysis and opti-mization at varying orientations and placements in aspect ofdistributed radiation at the interior surfacesrdquo Applied Energyvol 144 pp 152ndash164 2015

[5] V A A Raj and R Velraj ldquoReview on free cooling ofbuildings using phase change materialsrdquo Renewable andSustainable Energy Reviews vol 14 no 9 pp 2819ndash28292010

[6] A Pasupathy R Velraj and R V Seeniraj ldquoPhase ChangeMaterial-based building architecture for thermal manage-ment in residential and commercial establishmentsrdquo Re-newable and Sustainable Energy Reviews vol 12 no 1pp 39ndash64 2008

[7] S S Chandel and T Agarwal ldquoReview of current state ofresearch on energy storage toxicity health hazards andcommercialization of Phase Changing Materialsrdquo Renewableand Sustainable Energy Reviews vol 67 pp 581ndash596 2017

[8] H Akeiber P Nejat M Z A Majid et al ldquoA review on phasechange material (PCM) for sustainable passive cooling inbuilding envelopesrdquo Renewable and Sustainable Energy Re-views vol 60 pp 1470ndash1497 2016

[9] P K S Rathore and S K Shukla ldquoPotential of macro-encapsulated pcm for thermal energy storage in buildings acomprehensive reviewrdquo Construction and Building Materialsvol 225 pp 723ndash744 2019

[10] F Souayfane F Fardoun and P-H Biwole ldquoPhase ChangeMaterials (PCM) for cooling applications in buildings a re-viewrdquo Energy and Buildings vol 129 pp 396ndash431 2016

[11] R Jacob and F Bruno ldquoReview on shell materials used in theencapsulation of phase change materials for high temperaturethermal energy storagerdquo Renewable and Sustainable EnergyReviews vol 48 pp 79ndash87 2015

[12] H J Akeiber M A Wahid H M Hussen andA T Mohammad ldquoReview of development survey of phasechange material models in building applicationsrdquo ScientificWorld Journal vol 2014 pp 1ndash11 2014

[13] S R L da Cunha and J L B de Aguiar ldquoPhase ChangeMaterials and energy efficiency of buildings a review ofknowledgerdquo Journal of Energy Storage vol 271260 pages2020

[14] S Mengjie N Fuxin M Ning H Yanxin and D ShimingldquoReview on building energy performance improvement usingPhase Change Materialsrdquo Energy and Buildings vol 158pp 776ndash793 2018

[15] A Waqas and Z Ud Din ldquoPhase change material (PCM)storage for free cooling of buildings-A reviewrdquo Renewable andSustainable Energy Reviews vol 18 pp 607ndash625 2013

[16] S Ben Romdhane A Amamou R Ben Khalifa N M SaıdZ Younsi and A Jemni ldquoA review on thermal energy storageusing phase change materials in passive building applica-tionsrdquo Journal of Building Engineering vol 32 Article ID101563 2020

[17] Y Zhou S Zheng Z Liu et al ldquoPassive and active phasechange materials integrated building energy systems withadvanced machine-learning based climate-adaptive designsintelligent operations uncertainty-based analysis and opti-misations a state-of-the-art reviewrdquo Renewable and Sus-tainable Energy Reviews vol 130 Article ID 109889 2020

[18] Y Zhou S Zheng and G Zhang ldquoA review on coolingperformance enhancement for phase change materials inte-grated systems-flexible design and smart control with ma-chine learning applicationsrdquo Building and Environmentvol 174 Article ID 106786 2020

[19] F Kuznik and J Virgone ldquoExperimental investigation ofwallboard containing phase change material data for vali-dation of numerical modelingrdquo Energy and Buildings vol 41no 5 pp 561ndash570 2009

[20] I Mandilaras M Stamatiadou D Katsourinis G Zannis andM Founti ldquoExperimental thermal characterization of amediterranean residential building with pcm gypsum boardwallsrdquo Building and Environment vol 61 pp 93ndash103 2013

[21] D Mazzeo and G Oliveti ldquoParametric study and approxi-mation of the exact analytical solution of the stefan problem ina finite PCM layer in a steady periodic regimerdquo InternationalCommunications in Heat and Mass Transfer vol 84pp 49ndash65 2017

[22] D Mazzeo G Oliveti and N Arcuri ldquoDefinition of a new setof parameters for the dynamic thermal characterization ofPCM layers in the presence of one or more liquid-solid in-terfacesrdquo Energy and Buildings vol 141 pp 379ndash396 2017

[23] Y Zhou C W F Yu and G Zhang ldquoStudy on heat-transfermechanism of wallboards containing active phase changematerial and parameter optimization with ventilationrdquo Ap-plied 2ermal Engineering vol 144 pp 1091ndash1108 2018

[24] S G Yoon Y K Yang T W Kim M H Chung andJ C Park ldquo(ermal performance test of a phase-change-material cool roof system by a scaled modelrdquo Advances inCivil Engineering vol 2018 11 pages 2018

[25] X Jin M A Medina and X Zhang ldquoOn the importance ofthe location of pcms in building walls for enhanced thermalperformancerdquo Applied Energy vol 106 pp 72ndash78 2013


[26] E Tunccedilbilek M Arıcı M Krajcık S Nizetic and H Karabayldquo(ermal performance based optimization of an office wallcontaining PCM under intermittent cooling operationrdquoApplied 2ermal Engineering vol 179 Article ID 1157502020

[27] Z Liu Z Yu T Yang et al ldquoA review on macro-encapsulatedphase change material for building envelope applicationsrdquoBuilding and Environment vol 144 no April pp 281ndash2942018

[28] J Lei J Yang and E-H Yang ldquoEnergy performance ofbuilding envelopes integrated with phase change materials forcooling load reduction in tropical Singaporerdquo Applied Energyvol 162 pp 207ndash217 2016

[29] E Tunccedilbilek M Arıcı S Bouadila and S WonorahardjoldquoSeasonal and annual performance analysis of PCM-integratedbuilding brick under the climatic conditions ofMarmara regionrdquoJournal of 2ermal Analysis and Calorimetry vol 141 no 1pp 613ndash624 2020

[30] K Lee Ok M A Medina E Raith and X Sun ldquoAssessing theintegration of a thin phase change material (pcm) layer in aresidential building wall for heat transfer reduction andmanagementrdquo Applied Energy vol 137 pp 699ndash706 2014

[31] X Mi R Liu H Cui S A Memon F Xing and Y LoldquoEnergy and economic analysis of building integrated withpcm in different cities of Chinardquo Applied Energy vol 175pp 324ndash336 2016

[32] B Y Yun J H Park S Yang S Wi and S Kim ldquoIntegratedanalysis of the energy and economic efficiency of pcm as anindoor decoration element application to an apartmentbuildingrdquo Solar Energy vol 196 pp 437ndash447 2019

[33] E Solgi S Memarian and G N Moud ldquoFinancial viability ofpcms in countries with low energy cost a case study of dif-ferent climates in Iranrdquo Energy and Buildings vol 173pp 128ndash137 2018

[34] ASTMD5334-14 Standard Test Method for Determination of2ermal Conductivity of Soil And Soft Rock by2ermal NeedleProbe Procedure vol 04 no November pp 6ndash13 2016

[35] R Cheng M Pomianowski X Wang P Heiselberg andY Zhang ldquoA new method to determine thermophysicalproperties of PCM-concrete brickrdquo Applied Energy vol 112pp 988ndash998 2013

[36] J P Holman Experimental Methods for Engineers McGraw-Hill Companies New York NY USA 2012

[37] X Sun K O Lee M A Medina Y Chu and C Li ldquoMeltingtemperature and enthalpy variations of phase change mate-rials (PCMs) a differential scanning calorimetry (DSC)analysisrdquo Phase Transitions vol 91 no 6 pp 667ndash680 2018

[38] D Mazzeo G Oliveti A de Gracia J Coma A Sole andL F Cabeza ldquoExperimental validation of the exact analyticalsolution to the steady periodic heat transfer problem in a PCMlayerrdquo Energy vol 140 pp 1131ndash1147 2017

[39] S Shaik and A B Talanki Puttaranga Setty ldquoInfluence ofambient air relative humidity and temperature on thermalproperties and unsteady thermal response characteristics oflaterite wall housesrdquo Building and Environment vol 99pp 170ndash183 2016

[40] CIBSE CIBSE Environmental Design Guide A 2e CharteredInstitution of Building Services Engineers London LondonUK 2006

[41] K J Kontoleon and D K Bikas ldquo(e effect of south wallrsquosoutdoor absorption coefficient on time lag decrement factorand temperature variationsrdquo Energy and Buildings vol 39no 9 pp 1011ndash1018 2007

[42] S Shaik and A B P S Talanki ldquoOptimizing the position ofinsulating materials in flat roofs exposed to sunshine to gainminimum heat into buildings under periodic heat transferconditionsrdquo Environmental Science and Pollution Researchvol 23 no 10 pp 9334ndash9344 2016

[43] G M Soret P Vacca J Tignard et al ldquo(ermal inertia as anintegrative parameter for building performancerdquo Journal ofBuilding Engineering vol 33 Article ID 101623 2020

[44] ASHRAEAmerican Society Of Heating Refrigerating and Air-Conditioning Engineers Climatic Design InformationAtlanta USA Chapter 14 2009

[45] A Bolatturk ldquoOptimum insulation thicknesses for buildingwalls with respect to cooling and heating degree-hours in thewarmest zone of Turkeyrdquo Building and Environment vol 43no 6 pp 1055ndash1064 2008

[46] K G Kumar S Saboor V Kumar K H Kim andT P A Babu ldquoExperimental and theoretical studies of varioussolar control window glasses for the reduction of cooling andheating loads in buildings across different climatic regionsrdquoEnergy and Buildings vol 173 pp 326ndash336 2018

[47] J A Duffie and W A Beckman Solar Engineering of 2ermalProcesses John Wiley and Sons New York NY USA 2013


(e traditional means of building thermal conveniencesare mechanical air-conditioning systems that are energy-intensive and detrimental to the environment In this regardenergy-efficient and environmentally friendly techniquesapplied to boost thermal comfort at a zero or low powerconsumption are passive heating and cooling systems [3 4]Towards this goal terracotta bricks that are made of firedclay and have a good density which can provide a fairthermal resistance to building envelopes can be considered

(ermal energy storage by using PCMs is a tolerablepassive cooling approach to moderate heat flows throughbuilding envelopes PCMs can absorb a significant amountof heat during themelting stage (from solid to liquid) as wellas they can release the absorbed heat during the solidifi-cation stage (from liquid to solid) [5] (e ability of PCMs toprovide high energy storage and their characteristics toretain thermal storage at a constant temperature make theirutilization attractive for several building applications [6] Asit is widely known PCMs are commonly categorized asorganic inorganic and eutectic while they should havecertain characteristics such as a nontoxic and noncorrosivebehaviour a suitable thermal conductivity a desirable latentheat and a low cost to attain the fundamental goal of energyefficiency sustainably [7] Organic PCMs mostly shownoncorrosive properties and congruent melting points Inaddition to that the melting point and heat of the fusion ofcertain organic PCMs are suitable for the coolingheating ofbuildings [7] (e method to embed PCMs in the encap-sulation material with a scale exceeding 5mm is calledmacroencapsulation of PCMs while the shape of the shellcan vary (cylinders tubes cubes sticks etc) Macro-encapsulated PCMs can be used in any type size and di-mension of the building envelope [8] An active system withPCMs has a separate storage unit within the building to besettled which is considered to be a demerit for the end-users(e main benefit of incorporating PCMs into buildingmaterials is that less space is required while they can beformulated with a certain behavioural pattern at the veryearly stages of building construction [9] In the literaturevarious shell materials having the potential for thermalenergy storage at high temperatures are examined [10]Moreover several studies reviewed and addressed thethermal efficiency of PCM-integrated buildings as wallboardconfigurations assisted by the operation of the HVAC unit[11ndash18] PCM wallboards in buildings have recorded anadvantageous reduction of the decrement factor and in-crease of the time lag as regards the propagation of a pe-riodic heatwave [19ndash22] Zhou et al analytically investigateda ventilated Trombe wall integrated with double PCMwallboard (Inside and outside) and reported the energystorage and release efficiency of 202 (exterior) and 2025(interior) at the optimum PCM thicknesses (8mm for ex-terior and 28mm for interior) [23]

Yoon et al [24] experimentally studied a scaled model ofa PCM integrated cool roof system and reported a betterperformance for the RT44 PCM assembly for a white roof incomparison with the Bio 26PCM assembly for a brown roofJin et al [25] conducted the experiments and reported thatthe placement of the PCMpouch at a distance of (15) L from

the interior wall surface improves the overall thermalcomfort conditions Tunccedilbilek et al [26] conducted nu-merical simulation on PCM-integrated office building andreported energy savings of up to 128 with PCM of 23mmthickness located at the inner side of the wall A review of theuse of macroencapsulated PCMs for various building en-closures was presented in detail [27] (e thermal efficiencyof a concrete wall integrated with PCMs was analysed nu-merically by Lie et al As seen the incorporation of a 10mmthick PCM layer in a vertical wall leads to approximately20ndash30 reduction of heat gains through buildings located inhot tropical climates [28] (e thermal performance of thePCM integrated brick was numerically investigated byTunccedilbilek et al [29] and they reported the optimum PCMrsquosmelting temperatures as 18degC and 26degC respectively forwinter and summer seasons

(e PCM thermal shield position of a building model wasexperimentally investigated and optimized by Lee et al (eresults exposed the optimal location of PCM layers from theinner surface for various wall orientations [30] (e PCMimpact on building energy consumption was simulated forone whole year in five different cities in China by using EnergyPlus Results have underlined a significant energy saving inbuildings integrated with PCMs [31] PCM integration inbuildings was also modelled and simulated in terms of energydemands by Yun et al [32] Results have indicated a re-duction in cooling cost by 748 while a six yearsrsquo paybackperiod was estimated A building model integrated withPCMs for economic analysis was carried out with Energy Plussoftware by Solgi et al as seen the consideration of PCMs inbuildings lowered the energy requirements for certain ther-mal comfort requirements although it is not rational from aneconomical point of view in Iran due to the high cost of PCMsand the low costs of electricity [33]

(e literature revealed that there is no significant infor-mation on the air-conditioning cost-saving potential carbonemission mitigation and payback period by adopting PCMstuffed terracotta bricks in buildings In this respect the currentstudy aims to analyze numerically three different configura-tions of PCM stuffed terracotta bricks in addition five differenttypes of PCMs such as OM18 HS22 OM29 OM32 andOM37 were assessed for two different scenarios in India (hotdry and composite climates) (e thermophysical properties ofthe assumed PCMs were measured experimentally for bothsolid and liquid phases (is paper explores the unsteadythermal characteristics of PCM stuffed terracotta bricks andutilizes an unsteady thermal transmittance methodology todetermine the air-conditioning cost-saving within buildings(is paper also presents themitigation of carbon emissions andthe resulted payback periods for all analysed PCM stuffedterracotta brick buildings(e findings of this study help in thedesign of energy-efficient buildings with PCM integratedterracotta bricks

2 Materials and Methods

21 Materials (e terracotta bricks are natural materialsmade of clay that shows eco-friendly behaviour (e ter-racotta bricks are moulded with hollows to accommodate



















SolidPCMtemp



029m 014m

009m

(a)

P TB P

00125P + 014TB + 0125P

(b)

PCM

(c)

P TBTB PPCM

0125P + 0065TB + 001PCM + 0065TB + 00125P

(d)

(e)

P PTB TB TBPCM

PCM

00125P + 004TB + 001PCM + 004TB +001PCM + 004TB + 00125P

(f )

(g)

PTBTB TB TBPCM

PCM

PCM

P


(h)




UTB+PCMs 1ho

+Xp

kp

+Xtb

kcb+

Xpcm

kpcm+1hi

1113888 1113889

minus1

(1)


z2T

zx2

1α

zT

zτ

Te

qe

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦


c


⎡⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎣

⎤⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎦

Ti

qi

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦

(2)


ρcpkn



j


f1 f2

f3 f1

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦

b1 + ib2b3 + ib4( 1113857

c

c minusb4 + ib3( 1113857 b1 + ib2

⎡⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎣

⎤⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎦

b1 coshm cosm

b2 sinhm sinm


radic1113888 1113889


radic1113888 1113889

(3)


are given by

rst 1 h

minus1i


1 hminus1o

0 1⎡⎣ ⎤⎦ (4)


Te

qe

1113890 1113891 1 h

minus1i

0 1⎡⎣ ⎤⎦

m1 m2

m3 m11113890 1113891

n1 n2

n3 n11113890 1113891

1 hminus1o

0 1⎡⎣ ⎤⎦

Ti

qi

1113890 1113891

(5)


Te

qe

1113890 1113891 A1 A2

A3 A41113890 1113891

Ti

qi

1113890 1113891 (6)


3m3m

3m N

W

S

E

(a)

P

RCC

P

(b)



Ut 1

A2

11138681113868111386811138681113868111386811138681113868

11138681113868111386811138681113868111386811138681113868 (7)


f Ut

Us

(8)


φ 12πarctan

im(f)

Re(f)1113888 1113889 (9)







Cc 10minus 3

CeCDHΔUlt

COP1113888 1113889 (12)

Ch 10minus 3

CnHDHΔUst

η1113888 1113889 (13)


Ct Cc + Ch (14)




CDH

COP+ ΔUs

tp2HDH

η1113888 1113889 (15)




ln(1 + i)(1 + d) (16)







14000

12000

10000

8000

6000

4000

2000

0

2000


1632

72

3048

792

7056

4056

9744

7968

1171

210

488

1053

610

056

8448 87

84

7536

8424

7920

7416 76

8057

36

4752

2136 23

7621

6

168

2544

4855

2 24 48 4813

44

Ann

ual d

egre

e-ho

urs (

degC-h

ours

)











3 2 1 2

3 2 1 2

PCMTB-C(solid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-B(liquid)

PCMTB-A(solid)

PCMTB-A(liquid)

TB

UsUt

145143151159

164137135143144145

15148

15416166

144143

149149

1515515415816

167152151155155165

0770720810820850670640707908

078077084084086

075073077081083086084087087088

083082084085087

OM18OM18HS22HS22

OM29OM29


18253

(a)

80

75

70

65

60

45

4000

05

10

15

Tim

e lag

(h)

TB-DFTB-TL

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

Time lag

644 645

646 6

556

52

628 63 635 6

56

48

676

677 679 6

966

91

66 665 6

72 686

68

707 708 711

737

73

685 69 7

05 721

717

056

055

055

054

054

057

055 054 053

054

056 054

053 0

50

52

056 056 053 0

50

53

056 052 0

50

470

49

056 055

054 047

051

44

071

Decrement factor

PCMTB-A(liquid)

TB PCMTB-A(solid)

PCMTB-B(liquid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-C(solid)

80

75

70

65

60

45

4000

05

10

15

Dec

rem

ent f

acto

r

(b)















80

75

70

65

60

55

50

5

0

5

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


599

2 613

4

62

633

4

625

3

625

3

636

666

7 692

7

676

9

644

6

651

8

709

8

745

8

728

4

01 01 01 011 01 011 01 011 011 011 011 01 011 012 011



OM18 CCSOM18 HCS

HS22 CCSHS22 HCS

OM29 CCSOM29 HCS

OM32 CCSOM32 HCS

OM37 CCSOM37 HCS

PCMTB-C

PCMTB-B

PCMTB-A

P

P P

PP

PTB TB

TB

TBTB

TB

TB

TB

TB

PCM

PCM

PCM

PCM

PCM

PCM

(a)

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


65

60

55

50

45

40

35

30

0

5

10

480

8

492

2

497

4

508

2

501

7

501

7

510

3 534

9 555

8

543

1

517

2

522

9

569

5 598

4

584

5

173

175

177

181

175

181

177

181

194

192

186

179

184

204

194

PCMTB-A PCMTB-B

PCMTB-B

PCMTB-A

PCMTB-C

PCMTB-C




OM37 CCSOM37 HCS

PP

P P

PP

TB

TB

TB TB TB TB

TB TB

TBPCM

PCM

PCM

PCM

PCM

PCM

(b)









80

70

60

50

40

30

40

50

60

70

Tota

l bui

ldin

g ai

r con

ditio

ning

cost

savi

ngs (

$ye

ar)

Ahmedabad

600 614

621 63

4

626

626

637 66

8 694

678

646

653

711 74

7

730

498

510

515

526

519

520

528

553

575 56

2 536

541

588

619 604

Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P TBPCM

PCM

PCM

PCM

PCM

PCM

TB P

TB

TB

TB

TB

P

P

TB

TBTB

P

P



285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081



OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A


150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP




4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References



































































SolidPCMtemp



029m 014m

009m

(a)

P TB P

00125P + 014TB + 0125P

(b)

PCM

(c)

P TBTB PPCM

0125P + 0065TB + 001PCM + 0065TB + 00125P

(d)

(e)

P PTB TB TBPCM

PCM

00125P + 004TB + 001PCM + 004TB +001PCM + 004TB + 00125P

(f )

(g)

PTBTB TB TBPCM

PCM

PCM

P


(h)




UTB+PCMs 1ho

+Xp

kp

+Xtb

kcb+

Xpcm

kpcm+1hi

1113888 1113889

minus1

(1)


z2T

zx2

1α

zT

zτ

Te

qe

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦


c


⎡⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎣

⎤⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎦

Ti

qi

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦

(2)


ρcpkn



j


f1 f2

f3 f1

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦

b1 + ib2b3 + ib4( 1113857

c

c minusb4 + ib3( 1113857 b1 + ib2

⎡⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎣

⎤⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎦

b1 coshm cosm

b2 sinhm sinm


radic1113888 1113889


radic1113888 1113889

(3)


are given by

rst 1 h

minus1i


1 hminus1o

0 1⎡⎣ ⎤⎦ (4)


Te

qe

1113890 1113891 1 h

minus1i

0 1⎡⎣ ⎤⎦

m1 m2

m3 m11113890 1113891

n1 n2

n3 n11113890 1113891

1 hminus1o

0 1⎡⎣ ⎤⎦

Ti

qi

1113890 1113891

(5)


Te

qe

1113890 1113891 A1 A2

A3 A41113890 1113891

Ti

qi

1113890 1113891 (6)


3m3m

3m N

W

S

E

(a)

P

RCC

P

(b)



Ut 1

A2

11138681113868111386811138681113868111386811138681113868

11138681113868111386811138681113868111386811138681113868 (7)


f Ut

Us

(8)


φ 12πarctan

im(f)

Re(f)1113888 1113889 (9)







Cc 10minus 3

CeCDHΔUlt

COP1113888 1113889 (12)

Ch 10minus 3

CnHDHΔUst

η1113888 1113889 (13)


Ct Cc + Ch (14)




CDH

COP+ ΔUs

tp2HDH

η1113888 1113889 (15)




ln(1 + i)(1 + d) (16)







14000

12000

10000

8000

6000

4000

2000

0

2000


1632

72

3048

792

7056

4056

9744

7968

1171

210

488

1053

610

056

8448 87

84

7536

8424

7920

7416 76

8057

36

4752

2136 23

7621

6

168

2544

4855

2 24 48 4813

44

Ann

ual d

egre

e-ho

urs (

degC-h

ours

)











3 2 1 2

3 2 1 2

PCMTB-C(solid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-B(liquid)

PCMTB-A(solid)

PCMTB-A(liquid)

TB

UsUt

145143151159

164137135143144145

15148

15416166

144143

149149

1515515415816

167152151155155165

0770720810820850670640707908

078077084084086

075073077081083086084087087088

083082084085087

OM18OM18HS22HS22

OM29OM29


18253

(a)

80

75

70

65

60

45

4000

05

10

15

Tim

e lag

(h)

TB-DFTB-TL

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

Time lag

644 645

646 6

556

52

628 63 635 6

56

48

676

677 679 6

966

91

66 665 6

72 686

68

707 708 711

737

73

685 69 7

05 721

717

056

055

055

054

054

057

055 054 053

054

056 054

053 0

50

52

056 056 053 0

50

53

056 052 0

50

470

49

056 055

054 047

051

44

071

Decrement factor

PCMTB-A(liquid)

TB PCMTB-A(solid)

PCMTB-B(liquid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-C(solid)

80

75

70

65

60

45

4000

05

10

15

Dec

rem

ent f

acto

r

(b)















80

75

70

65

60

55

50

5

0

5

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


599

2 613

4

62

633

4

625

3

625

3

636

666

7 692

7

676

9

644

6

651

8

709

8

745

8

728

4

01 01 01 011 01 011 01 011 011 011 011 01 011 012 011



OM18 CCSOM18 HCS

HS22 CCSHS22 HCS

OM29 CCSOM29 HCS

OM32 CCSOM32 HCS

OM37 CCSOM37 HCS

PCMTB-C

PCMTB-B

PCMTB-A

P

P P

PP

PTB TB

TB

TBTB

TB

TB

TB

TB

PCM

PCM

PCM

PCM

PCM

PCM

(a)

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


65

60

55

50

45

40

35

30

0

5

10

480

8

492

2

497

4

508

2

501

7

501

7

510

3 534

9 555

8

543

1

517

2

522

9

569

5 598

4

584

5

173

175

177

181

175

181

177

181

194

192

186

179

184

204

194

PCMTB-A PCMTB-B

PCMTB-B

PCMTB-A

PCMTB-C

PCMTB-C




OM37 CCSOM37 HCS

PP

P P

PP

TB

TB

TB TB TB TB

TB TB

TBPCM

PCM

PCM

PCM

PCM

PCM

(b)









80

70

60

50

40

30

40

50

60

70

Tota

l bui

ldin

g ai

r con

ditio

ning

cost

savi

ngs (

$ye

ar)

Ahmedabad

600 614

621 63

4

626

626

637 66

8 694

678

646

653

711 74

7

730

498

510

515

526

519

520

528

553

575 56

2 536

541

588

619 604

Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P TBPCM

PCM

PCM

PCM

PCM

PCM

TB P

TB

TB

TB

TB

P

P

TB

TBTB

P

P



285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081



OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A


150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP




4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References



















































UTB+PCMs 1ho

+Xp

kp

+Xtb

kcb+

Xpcm

kpcm+1hi

1113888 1113889

minus1

(1)


z2T

zx2

1α

zT

zτ

Te

qe

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦


c


⎡⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎣

⎤⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎦

Ti

qi

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦

(2)


ρcpkn



j


f1 f2

f3 f1

⎡⎢⎢⎢⎣ ⎤⎥⎥⎥⎦

b1 + ib2b3 + ib4( 1113857

c

c minusb4 + ib3( 1113857 b1 + ib2

⎡⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎣

⎤⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎦

b1 coshm cosm

b2 sinhm sinm


radic1113888 1113889


radic1113888 1113889

(3)


are given by

rst 1 h

minus1i


1 hminus1o

0 1⎡⎣ ⎤⎦ (4)


Te

qe

1113890 1113891 1 h

minus1i

0 1⎡⎣ ⎤⎦

m1 m2

m3 m11113890 1113891

n1 n2

n3 n11113890 1113891

1 hminus1o

0 1⎡⎣ ⎤⎦

Ti

qi

1113890 1113891

(5)


Te

qe

1113890 1113891 A1 A2

A3 A41113890 1113891

Ti

qi

1113890 1113891 (6)


3m3m

3m N

W

S

E

(a)

P

RCC

P

(b)



Ut 1

A2

11138681113868111386811138681113868111386811138681113868

11138681113868111386811138681113868111386811138681113868 (7)


f Ut

Us

(8)


φ 12πarctan

im(f)

Re(f)1113888 1113889 (9)







Cc 10minus 3

CeCDHΔUlt

COP1113888 1113889 (12)

Ch 10minus 3

CnHDHΔUst

η1113888 1113889 (13)


Ct Cc + Ch (14)




CDH

COP+ ΔUs

tp2HDH

η1113888 1113889 (15)




ln(1 + i)(1 + d) (16)







14000

12000

10000

8000

6000

4000

2000

0

2000


1632

72

3048

792

7056

4056

9744

7968

1171

210

488

1053

610

056

8448 87

84

7536

8424

7920

7416 76

8057

36

4752

2136 23

7621

6

168

2544

4855

2 24 48 4813

44

Ann

ual d

egre

e-ho

urs (

degC-h

ours

)











3 2 1 2

3 2 1 2

PCMTB-C(solid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-B(liquid)

PCMTB-A(solid)

PCMTB-A(liquid)

TB

UsUt

145143151159

164137135143144145

15148

15416166

144143

149149

1515515415816

167152151155155165

0770720810820850670640707908

078077084084086

075073077081083086084087087088

083082084085087

OM18OM18HS22HS22

OM29OM29


18253

(a)

80

75

70

65

60

45

4000

05

10

15

Tim

e lag

(h)

TB-DFTB-TL

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

Time lag

644 645

646 6

556

52

628 63 635 6

56

48

676

677 679 6

966

91

66 665 6

72 686

68

707 708 711

737

73

685 69 7

05 721

717

056

055

055

054

054

057

055 054 053

054

056 054

053 0

50

52

056 056 053 0

50

53

056 052 0

50

470

49

056 055

054 047

051

44

071

Decrement factor

PCMTB-A(liquid)

TB PCMTB-A(solid)

PCMTB-B(liquid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-C(solid)

80

75

70

65

60

45

4000

05

10

15

Dec

rem

ent f

acto

r

(b)















80

75

70

65

60

55

50

5

0

5

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


599

2 613

4

62

633

4

625

3

625

3

636

666

7 692

7

676

9

644

6

651

8

709

8

745

8

728

4

01 01 01 011 01 011 01 011 011 011 011 01 011 012 011



OM18 CCSOM18 HCS

HS22 CCSHS22 HCS

OM29 CCSOM29 HCS

OM32 CCSOM32 HCS

OM37 CCSOM37 HCS

PCMTB-C

PCMTB-B

PCMTB-A

P

P P

PP

PTB TB

TB

TBTB

TB

TB

TB

TB

PCM

PCM

PCM

PCM

PCM

PCM

(a)

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


65

60

55

50

45

40

35

30

0

5

10

480

8

492

2

497

4

508

2

501

7

501

7

510

3 534

9 555

8

543

1

517

2

522

9

569

5 598

4

584

5

173

175

177

181

175

181

177

181

194

192

186

179

184

204

194

PCMTB-A PCMTB-B

PCMTB-B

PCMTB-A

PCMTB-C

PCMTB-C




OM37 CCSOM37 HCS

PP

P P

PP

TB

TB

TB TB TB TB

TB TB

TBPCM

PCM

PCM

PCM

PCM

PCM

(b)









80

70

60

50

40

30

40

50

60

70

Tota

l bui

ldin

g ai

r con

ditio

ning

cost

savi

ngs (

$ye

ar)

Ahmedabad

600 614

621 63

4

626

626

637 66

8 694

678

646

653

711 74

7

730

498

510

515

526

519

520

528

553

575 56

2 536

541

588

619 604

Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P TBPCM

PCM

PCM

PCM

PCM

PCM

TB P

TB

TB

TB

TB

P

P

TB

TBTB

P

P



285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081



OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A


150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP




4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References


















































Ut 1

A2

11138681113868111386811138681113868111386811138681113868

11138681113868111386811138681113868111386811138681113868 (7)


f Ut

Us

(8)


φ 12πarctan

im(f)

Re(f)1113888 1113889 (9)







Cc 10minus 3

CeCDHΔUlt

COP1113888 1113889 (12)

Ch 10minus 3

CnHDHΔUst

η1113888 1113889 (13)


Ct Cc + Ch (14)




CDH

COP+ ΔUs

tp2HDH

η1113888 1113889 (15)




ln(1 + i)(1 + d) (16)







14000

12000

10000

8000

6000

4000

2000

0

2000


1632

72

3048

792

7056

4056

9744

7968

1171

210

488

1053

610

056

8448 87

84

7536

8424

7920

7416 76

8057

36

4752

2136 23

7621

6

168

2544

4855

2 24 48 4813

44

Ann

ual d

egre

e-ho

urs (

degC-h

ours

)











3 2 1 2

3 2 1 2

PCMTB-C(solid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-B(liquid)

PCMTB-A(solid)

PCMTB-A(liquid)

TB

UsUt

145143151159

164137135143144145

15148

15416166

144143

149149

1515515415816

167152151155155165

0770720810820850670640707908

078077084084086

075073077081083086084087087088

083082084085087

OM18OM18HS22HS22

OM29OM29


18253

(a)

80

75

70

65

60

45

4000

05

10

15

Tim

e lag

(h)

TB-DFTB-TL

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

Time lag

644 645

646 6

556

52

628 63 635 6

56

48

676

677 679 6

966

91

66 665 6

72 686

68

707 708 711

737

73

685 69 7

05 721

717

056

055

055

054

054

057

055 054 053

054

056 054

053 0

50

52

056 056 053 0

50

53

056 052 0

50

470

49

056 055

054 047

051

44

071

Decrement factor

PCMTB-A(liquid)

TB PCMTB-A(solid)

PCMTB-B(liquid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-C(solid)

80

75

70

65

60

45

4000

05

10

15

Dec

rem

ent f

acto

r

(b)















80

75

70

65

60

55

50

5

0

5

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


599

2 613

4

62

633

4

625

3

625

3

636

666

7 692

7

676

9

644

6

651

8

709

8

745

8

728

4

01 01 01 011 01 011 01 011 011 011 011 01 011 012 011



OM18 CCSOM18 HCS

HS22 CCSHS22 HCS

OM29 CCSOM29 HCS

OM32 CCSOM32 HCS

OM37 CCSOM37 HCS

PCMTB-C

PCMTB-B

PCMTB-A

P

P P

PP

PTB TB

TB

TBTB

TB

TB

TB

TB

PCM

PCM

PCM

PCM

PCM

PCM

(a)

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


65

60

55

50

45

40

35

30

0

5

10

480

8

492

2

497

4

508

2

501

7

501

7

510

3 534

9 555

8

543

1

517

2

522

9

569

5 598

4

584

5

173

175

177

181

175

181

177

181

194

192

186

179

184

204

194

PCMTB-A PCMTB-B

PCMTB-B

PCMTB-A

PCMTB-C

PCMTB-C




OM37 CCSOM37 HCS

PP

P P

PP

TB

TB

TB TB TB TB

TB TB

TBPCM

PCM

PCM

PCM

PCM

PCM

(b)









80

70

60

50

40

30

40

50

60

70

Tota

l bui

ldin

g ai

r con

ditio

ning

cost

savi

ngs (

$ye

ar)

Ahmedabad

600 614

621 63

4

626

626

637 66

8 694

678

646

653

711 74

7

730

498

510

515

526

519

520

528

553

575 56

2 536

541

588

619 604

Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P TBPCM

PCM

PCM

PCM

PCM

PCM

TB P

TB

TB

TB

TB

P

P

TB

TBTB

P

P



285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081



OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A


150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP




4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References




















































14000

12000

10000

8000

6000

4000

2000

0

2000


1632

72

3048

792

7056

4056

9744

7968

1171

210

488

1053

610

056

8448 87

84

7536

8424

7920

7416 76

8057

36

4752

2136 23

7621

6

168

2544

4855

2 24 48 4813

44

Ann

ual d

egre

e-ho

urs (

degC-h

ours

)











3 2 1 2

3 2 1 2

PCMTB-C(solid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-B(liquid)

PCMTB-A(solid)

PCMTB-A(liquid)

TB

UsUt

145143151159

164137135143144145

15148

15416166

144143

149149

1515515415816

167152151155155165

0770720810820850670640707908

078077084084086

075073077081083086084087087088

083082084085087

OM18OM18HS22HS22

OM29OM29


18253

(a)

80

75

70

65

60

45

4000

05

10

15

Tim

e lag

(h)

TB-DFTB-TL

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

Time lag

644 645

646 6

556

52

628 63 635 6

56

48

676

677 679 6

966

91

66 665 6

72 686

68

707 708 711

737

73

685 69 7

05 721

717

056

055

055

054

054

057

055 054 053

054

056 054

053 0

50

52

056 056 053 0

50

53

056 052 0

50

470

49

056 055

054 047

051

44

071

Decrement factor

PCMTB-A(liquid)

TB PCMTB-A(solid)

PCMTB-B(liquid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-C(solid)

80

75

70

65

60

45

4000

05

10

15

Dec

rem

ent f

acto

r

(b)















80

75

70

65

60

55

50

5

0

5

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


599

2 613

4

62

633

4

625

3

625

3

636

666

7 692

7

676

9

644

6

651

8

709

8

745

8

728

4

01 01 01 011 01 011 01 011 011 011 011 01 011 012 011



OM18 CCSOM18 HCS

HS22 CCSHS22 HCS

OM29 CCSOM29 HCS

OM32 CCSOM32 HCS

OM37 CCSOM37 HCS

PCMTB-C

PCMTB-B

PCMTB-A

P

P P

PP

PTB TB

TB

TBTB

TB

TB

TB

TB

PCM

PCM

PCM

PCM

PCM

PCM

(a)

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


65

60

55

50

45

40

35

30

0

5

10

480

8

492

2

497

4

508

2

501

7

501

7

510

3 534

9 555

8

543

1

517

2

522

9

569

5 598

4

584

5

173

175

177

181

175

181

177

181

194

192

186

179

184

204

194

PCMTB-A PCMTB-B

PCMTB-B

PCMTB-A

PCMTB-C

PCMTB-C




OM37 CCSOM37 HCS

PP

P P

PP

TB

TB

TB TB TB TB

TB TB

TBPCM

PCM

PCM

PCM

PCM

PCM

(b)









80

70

60

50

40

30

40

50

60

70

Tota

l bui

ldin

g ai

r con

ditio

ning

cost

savi

ngs (

$ye

ar)

Ahmedabad

600 614

621 63

4

626

626

637 66

8 694

678

646

653

711 74

7

730

498

510

515

526

519

520

528

553

575 56

2 536

541

588

619 604

Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P TBPCM

PCM

PCM

PCM

PCM

PCM

TB P

TB

TB

TB

TB

P

P

TB

TBTB

P

P



285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081



OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A


150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP




4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References




















































3 2 1 2

3 2 1 2

PCMTB-C(solid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-B(liquid)

PCMTB-A(solid)

PCMTB-A(liquid)

TB

UsUt

145143151159

164137135143144145

15148

15416166

144143

149149

1515515415816

167152151155155165

0770720810820850670640707908

078077084084086

075073077081083086084087087088

083082084085087

OM18OM18HS22HS22

OM29OM29


18253

(a)

80

75

70

65

60

45

4000

05

10

15

Tim

e lag

(h)

TB-DFTB-TL

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

Time lag

644 645

646 6

556

52

628 63 635 6

56

48

676

677 679 6

966

91

66 665 6

72 686

68

707 708 711

737

73

685 69 7

05 721

717

056

055

055

054

054

057

055 054 053

054

056 054

053 0

50

52

056 056 053 0

50

53

056 052 0

50

470

49

056 055

054 047

051

44

071

Decrement factor

PCMTB-A(liquid)

TB PCMTB-A(solid)

PCMTB-B(liquid)

PCMTB-C(liquid)

PCMTB-B(solid)

PCMTB-C(solid)

80

75

70

65

60

45

4000

05

10

15

Dec

rem

ent f

acto

r

(b)















80

75

70

65

60

55

50

5

0

5

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


599

2 613

4

62

633

4

625

3

625

3

636

666

7 692

7

676

9

644

6

651

8

709

8

745

8

728

4

01 01 01 011 01 011 01 011 011 011 011 01 011 012 011



OM18 CCSOM18 HCS

HS22 CCSHS22 HCS

OM29 CCSOM29 HCS

OM32 CCSOM32 HCS

OM37 CCSOM37 HCS

PCMTB-C

PCMTB-B

PCMTB-A

P

P P

PP

PTB TB

TB

TBTB

TB

TB

TB

TB

PCM

PCM

PCM

PCM

PCM

PCM

(a)

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


65

60

55

50

45

40

35

30

0

5

10

480

8

492

2

497

4

508

2

501

7

501

7

510

3 534

9 555

8

543

1

517

2

522

9

569

5 598

4

584

5

173

175

177

181

175

181

177

181

194

192

186

179

184

204

194

PCMTB-A PCMTB-B

PCMTB-B

PCMTB-A

PCMTB-C

PCMTB-C




OM37 CCSOM37 HCS

PP

P P

PP

TB

TB

TB TB TB TB

TB TB

TBPCM

PCM

PCM

PCM

PCM

PCM

(b)









80

70

60

50

40

30

40

50

60

70

Tota

l bui

ldin

g ai

r con

ditio

ning

cost

savi

ngs (

$ye

ar)

Ahmedabad

600 614

621 63

4

626

626

637 66

8 694

678

646

653

711 74

7

730

498

510

515

526

519

520

528

553

575 56

2 536

541

588

619 604

Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P TBPCM

PCM

PCM

PCM

PCM

PCM

TB P

TB

TB

TB

TB

P

P

TB

TBTB

P

P



285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081



OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A


150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP




4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References






























































80

75

70

65

60

55

50

5

0

5

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


599

2 613

4

62

633

4

625

3

625

3

636

666

7 692

7

676

9

644

6

651

8

709

8

745

8

728

4

01 01 01 011 01 011 01 011 011 011 011 01 011 012 011



OM18 CCSOM18 HCS

HS22 CCSHS22 HCS

OM29 CCSOM29 HCS

OM32 CCSOM32 HCS

OM37 CCSOM37 HCS

PCMTB-C

PCMTB-B

PCMTB-A

P

P P

PP

PTB TB

TB

TBTB

TB

TB

TB

TB

PCM

PCM

PCM

PCM

PCM

PCM

(a)

Coo

ling

and

heat

ing

cost

savi

ngs (

$ye

ar)


65

60

55

50

45

40

35

30

0

5

10

480

8

492

2

497

4

508

2

501

7

501

7

510

3 534

9 555

8

543

1

517

2

522

9

569

5 598

4

584

5

173

175

177

181

175

181

177

181

194

192

186

179

184

204

194

PCMTB-A PCMTB-B

PCMTB-B

PCMTB-A

PCMTB-C

PCMTB-C




OM37 CCSOM37 HCS

PP

P P

PP

TB

TB

TB TB TB TB

TB TB

TBPCM

PCM

PCM

PCM

PCM

PCM

(b)









80

70

60

50

40

30

40

50

60

70

Tota

l bui

ldin

g ai

r con

ditio

ning

cost

savi

ngs (

$ye

ar)

Ahmedabad

600 614

621 63

4

626

626

637 66

8 694

678

646

653

711 74

7

730

498

510

515

526

519

520

528

553

575 56

2 536

541

588

619 604

Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P TBPCM

PCM

PCM

PCM

PCM

PCM

TB P

TB

TB

TB

TB

P

P

TB

TBTB

P

P



285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081



OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A


150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP




4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References
























































80

70

60

50

40

30

40

50

60

70

Tota

l bui

ldin

g ai

r con

ditio

ning

cost

savi

ngs (

$ye

ar)

Ahmedabad

600 614

621 63

4

626

626

637 66

8 694

678

646

653

711 74

7

730

498

510

515

526

519

520

528

553

575 56

2 536

541

588

619 604

Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P TBPCM

PCM

PCM

PCM

PCM

PCM

TB P

TB

TB

TB

TB

P

P

TB

TBTB

P

P



285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081



OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A


150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP




4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References


















































285266

419255

402

211197

313181

291

119112

17997

161

241225

357216

343

178166

265152

247

10094

15081



OM18

OM18

HS22

HS22

OM29

OM29

OM32

OM32

OM37

OM37

50 40 30 20 10 10 20 30 40

PCMTB-A

PCMTB-B

PCMTB-C

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PPPCMTB-C

PCMTB-B

PCMTB-A


150

125

100

075

050

075

100

125

Tota

l car

bon

emiss

ions

miti

gatio

n (to

nkW

h)Ahmedabad

115 117 119 121

120

120 122 1

28 133

130

123 125

136 1

43

139

094

096

097

099 098

098

099

104

108 106 1

01

102

111

117 1

14Lucknow

PCMTB-A

PCMTB-A

PCMTB-B

PCMTB-B

PCMTB-C

PCMTB-C

OM18OM18

HS22HS22

OM29OM29

OM32OM32

OM37OM37

P

P

TBPCM

TB

TBTB

TB TB TB TB

PCM

PCM

PCM

PCM

PCM

TB

P

P

PP




4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References



















































4 Conclusions











Nomenclature




Greek letters


Acronyms




Data Availability


Disclosure




References



















































Data Availability


Disclosure




References


















































thermal behaviour analysis and cost-saving opportunities

Documents