8/13/2019 Hadi Ate2013

1/5

Phase change material: Optimizing the thermal properties andthermal conductivity of myristic acid/palmitic acid eutectic mixturewith acid-based surfactantsq

Hadi Fauzi a,c,*, Hendrik S.C. Metselaar a,*, T.M.I. Mahlia b, Mahyar Silakhori a, Hadi Nur d

a Department of Mechanical Engineering, University Malaya, Kuala Lumpur 50603, Malaysiab Department of Mechanical Engineering, Universiti Tenaga Nasional, Kajang 43000, Selangor, Malaysiac Department of Chemical Engineering, Syiah Kuala University, Banda Aceh 23111, Indonesiad Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia

h i g h l i g h t s

Myristic acid (MA) and palmitic acid (PA) are fatty acids component.The eutectic composition ratio of MA/PA obtained at 70/30, wt.%.5% each acid-based surfactants were reduces the melting and undercooling temperature of MA/PA (70/30, wt.%).Thermal conductivity and DHfof MA/PA (70/30, wt.%) were increased by adding 5% surfactants.MA/PA 5% acid-based surfactants have a great potential to apply in LHTES applications.

a r t i c l e i n f o

Article history:

Received 14 March 2013Accepted 24 June 2013Available online 4 July 2013

Keywords:

Phase change materialLatent heat storageSurfactant additivesFatty acidThermal propertiesThermal conductivity

a b s t r a c t

In this study the addition of surfactant to fatty acids as phase change materials (PCMs) for solar thermalapplications is proposed. The incorporation of surfactant additives into a eutectic mixture of fatty acids

can signicantly increase the value of latent heat storage and can suppress undercooling. We report thepreparation of myristic acid/palmitic acid (MA/PA) eutectic mixture as Phase Change Material (PCM) withaddition of 0, 5, 10, 15, and 20% sodium myristate (SM), sodium palmitate (SP), and sodium stearate (SS),the inuence of surfactant additives on thermal properties and thermal conductivity of eutectic mix-tures. It was found that the addition of 5% SM, 5% SP, and 5% SS to MA/PA eutectic mixture is veryeffective in depressing the liquid/solid phase change temperature, reducing the undercooling andincreasing the amount of latent heat of fusion as well as thermal conductivity of eutectic PCM comparedto eutectic PCM without surfactants. Furthermore MA/PA 5%SS has the highest latent heat of fusion of191.85 J g1, while MA/PA 5%SM showed the least undercooling of 0.34 C and the highest thermalconductivity of 0.242 W m1 K1.

2013 Elsevier Ltd. All rights reserved.

1. Introduction

Research and development on thermal energy storage (TES)have been conducted in order to obtain a heat storage system witha high heat capacity and good heat transfer mechanism. Deter-mining the appropriate material to store the heat is the key indevelopment of heat storage systems, particularly the investigationof solideliquid phase change materials (PCMs) due to the followingconsiderations: suitable range temperature, involves high latentheat PCMs, narrow phase transition temperature [1,2].

The selection of a suitable heat storage material is a very impor-tant factor in optimizing the thermal efciency, economic feasibility,and durability of latent heat thermal energy storage (LHTES) systems

q The submitted manuscript has been created by Mechanical EngineeringDepartment, managed by University Malaya through High Impact Research grantunder contract No. UM.R/HIR/MOHE/ENG/21-D000021-16001 with MalaysianMinistry of Higher Education and University of Malaya Research Grant No. UMRGRP021-2012A.* Corresponding authors. Department of Mechanical Engineering, University

Malaya, Kuala Lumpur 50603, Malaysia. Tel.: 60 3 79674451; fax: 60 3 796744.E-mail addresses: hadidoank@gmail.com (H. Fauzi), h.metselaar@um.edu.my

(H.S.C. Metselaar).

Contents lists available atSciVerse ScienceDirect

Applied Thermal Engineering

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m/ l o c a t e / a p t h e r m e n g

1359-4311/$e see front matter 2013 Elsevier Ltd. All rights reserved.

http://dx.doi.org/10.1016/j.applthermaleng.2013.06.050

Applied Thermal Engineering 60 (2013) 261e265

mailto:hadidoank@gmail.commailto:h.metselaar@um.edu.myhttp://www.sciencedirect.com/science/journal/13594311http://www.elsevier.com/locate/apthermenghttp://dx.doi.org/10.1016/j.applthermaleng.2013.06.050http://dx.doi.org/10.1016/j.applthermaleng.2013.06.050http://dx.doi.org/10.1016/j.applthermaleng.2013.06.050http://dx.doi.org/10.1016/j.applthermaleng.2013.06.050http://dx.doi.org/10.1016/j.applthermaleng.2013.06.050http://dx.doi.org/10.1016/j.applthermaleng.2013.06.050http://www.elsevier.com/locate/apthermenghttp://www.sciencedirect.com/science/journal/13594311http://crossmark.dyndns.org/dialog/?doi=10.1016/j.applthermaleng.2013.06.050&domain=pdfmailto:h.metselaar@um.edu.mymailto:hadidoank@gmail.com

8/13/2019 Hadi Ate2013

2/5

[3]. In general, the disadvantages of materials in LHTES are the lowthermal conductivity, density changes and thermal stability proper-ties for long time utilization, and large undercooling [3].

Materials that have been developed for LHTES are organic orinorganic. In previous studies, the thermal properties and thermalstability of PCMs eutectic mixture such as Mg(NO3)2$NH4NO3 6H2O (61.5/38.5, wt.%), Mg(NO3)2$6H2O MgCl2$6H2O (58.7/41.3,wt.%), Mg (NO3)2$6H2O Al(NO3)2$9H2O (53/47, wt.%), urea acetamide (37.5/63.5, wt.%), naphthalene benzoic acid (67.1/32.9,wt.%) were investigated, and it was concluded that those eutecticshave potential as PCM for LHTES[2,4e6]. Moreover, the fatty acideutectic mixtures have better stability than inorganic eutectic PCMsafter a large number of thermal cycles[1,7,8].

Fatty acids are selected for the development of heat storagematerial because they have thermodynamic and kinetic propertiessuitable for low temperature latent heat storage [4,9e12]. Fattyacids have a high latent heat of fusion and their volume changesduring the phase transition are insignicant[11]. They also have asuitable melting temperature range for solar heating application[13]. These make them superior over other PCMs mostly due tocongruent melting, good chemical stability and non-toxicity.Furthermore, fatty acids are more sustainable than other PCMs

because they are derived from common vegetable and animal oils,which are renewable materials[14,15].

Saret al.[1,7,16]prepared the myristic acid/palmitic acid (MA/PA) eutectic mixture and the result show that the melting tem-perature and latent heat of fusion of MA/PA eutectic mixture are42.6 C (58/42, wt.%) and 169.7 J g1, respectively[16].Matsui et al.[17]improved the phase transition temperature and latent heat offusion capric acid/lauric acid (70/30, wt.%) eutectic mixture byadding the acid based surfactant additives of 5, 10, 15, and 20%,respectively. In a recent study on MA and PA, the phase transitiontemperature and latent heat of fusion MA/PA eutectic mixture wasimproved by the addition of acid-based surfactants.

The objectives of this study to determine the suitable phasechange transition temperature and the optimum latent heat of

fusionof preparedMA/PA eutectic mixture and to observe the effectof adding surfactant additives such as sodium myristate (SM), so-dium palmitate (SP), and sodium stearate (SS) as much as 5, 10, 15,and 20%, respectively. The thermal properties were determinedusing Differential Scanning Calorimetric (DSC) analysis techniques,

and the thermal conductivity of eutectics PCM was evaluated usingthe hot wire method by KD2Pro thermal conductivity analysis.

2. Materials and methods

2.1. Preparation of MA/PA eutectic mixture

A eutectic mixture of myristic acid/palmitic acid (MA/PA) wasformulated by blending the single components with mass fractioncomposition ratio of 0e100% in intervals of 10%. Refer to Fig.1, 2 g o f each mixture of MA and PA was blended in a jacketed ask reactorcontacting with heat transfer uid (HTF) at a temperature of 80 C,whereas the previous research used a hotplate for heating [10]. Theproposed modication was to spread heat evenly across the surfaceof the reactor, so the eutectic PCM mixed more homogenously. Themixture was stirred for 20 min and then cooled to room temper-ature. Surfactant with acid based properties of sodium myristate(pure, 99%), sodium palmitate (pure, 98.5%), and sodium stearate(pure, 99%) in the amount of 5, 10, 15, and 20% was added. Myristicacid (pure, 99%) and palmitic acid (pure, 98%) were obtained fromAcros Organic meanwhile sodium myristate (SM), sodium palmi-tate (SP), and sodium stearate (SS) were obtained from Sigma

Aldrich, both fatty acids and surfactants were used without furtherpurication.

2.2. DSC thermal properties analysis

Thermal properties such as melting temperature (Tm), solidify-ing temperature (Ts), and the latent heat of fusion (DHf) ofpure MA/PA and MA/PA with surfactant additives were identied using DSCthermal analysis (Mettler Toledo, DSC1 Stare system). The heatingand cooling rate were set to 5 C min1. To obtain an accurateanalysis, determinationof thermal properties was repeated 3 times.Standard deviation of liquid/solid phase change temperature andlatent heat of MA/PA eutectic mixture obtained were 0.064 C and2.7 J g1, respectively.

2.3. Thermal conductivity analysis

Thermal conductivity of pure MA/PA and MA/PA with surfactantadditives was determined using the hot wire method KD2Pro

Fig. 1. Preparation process of eutectic mixtures MA/PA.

H. Fauzi et al. / Applied Thermal Engineering 60 (2013) 261e265262

8/13/2019 Hadi Ate2013

3/5

thermal conductivity analyzer (Decagon, USA). Sensor used was thesingle needle (TR-1) with a diameter of 2.4 mm and a length of100 mm.

3. Results and discussion

3.1. Thermal properties of MA/PA eutectic mixture

The DSC curve analysis of single component fatty acids and fattyacid mixtures is shown in Fig. 2. The determination of melting/solidication temperature and latent heat of fusion of eutectic PCMwas located from onset and normalized value in original graph ofDSC analysis. It was shows that the melting temperature of MA and

PAcomponents was 54.7

C and 63.08

C, and that the latent heat offusion (DHf) was 161.37 J g1 and 173.69 J g1, respectively. Thus,

both of these components areselectedas candidates to form MA/PAeutectic mixture with a large latent heat storage and suitable phasechange temperature in LHTES applications. The prepared eutecticmixture of MA/PA in Fig. 3 shows that the lowest melting tem-perature occurs at the composition ratio 70/30 wt.%. Therefore thiscomposition was used for further investigation. The same condition

also reported by Karaipekli et al. [9,10]that obtained the meltingtemperature of CA/SA eutectic mixture (83/17, wt.%), CA/LA (64/36,wt.%), and CA/MA (73/27, wt.%) which were lower than the meltingtemperatures of their single components.

However, the phase transition temperature of MA/PA eutecticmixture (70/30, wt.%) indicated the occurrence of undercooling asthere is a gap between the melting temperature and solidifyingtemperature of the eutectic mixture: the melting and solidifyingtemperatures of MA/PA were 46.73C and 44.76 C, respectively. Inthis experiment, we expected the range of liquid/solid phasechange temperature of eutectic PCM of 35e45 C, and high latentheat. Therefore, the surfactant additives with acids base propertieswere added to MA/PA eutectic PCM to control the undercooling anddepress the melting temperature as well as to increase the latent

heat amount of the MA/PA eutectic mixture.

3.2. Effect of surfactant additives

Surfactants such as sodium myristate (SM), sodium palmitate(SP), and sodium stearate (SS) were added to the MA/PA (70/30,

Fig. 2. DSC curve of thermal properties of MA, PA components, and MA/PA eutectic

mixture.

Fig. 3. Curve of melting and solidifying temperature of MA/PA (70/30, wt.%) eutectic

mixture.

Fig. 4. DSC curve thermal properties of MA/PA (70/30, wt.%) and MA/PA (70/30,

wt.%) 5%SM.

Fig. 5. DSC curve thermal properties of MA/PA (70/30, wt.%) and MA/PA (70/30,

wt.%)

5%SP.

H. Fauzi et al. / Applied Thermal Engineering 60 (2013) 261e265 263

8/13/2019 Hadi Ate2013

4/5

wt.%) as a control agent to minimize undercooling and depress thephase change temperature of the eutectic mixture[17]. DSC curvesinFigs. 4e6show the effect of SM, SP, and SS addition respectively5% signicantly in improving the thermal properties of MA/PAeutectic mixture. In order to decrease the melting temperature to41.36 C, 41.58 C, 41.81 C and increase the latent heat of fusionvalue reach to 179.12 J g1,184.14 J g1, and 191.85 J g1, respectively(Table 1).

Thermal properties of MA/PA (70/30, wt.%) eutectic mixturewith addition of SM, SP, and SS obtained in this study are shown inTables 2e4.The addition of SM inTable 2clearly shows that 5% SMwas a suitable composition in obtained the lowest solid/liquidphase transition temperature with low subcooling and good latentheat of fusionvalue is179.12 J g1 compare to others composition of

SM. Even though MA/PA with 10% SM indicated the higher latentheat of fusion, but it does not signicantly lower the solid/liquidphase transition temperature of MA/PA eutectic mixture and it haslarge subcooling temperature. The same phenomenon is also

shown in the addition of SP and SS. Tables 3and4shows that the

MA/PA with 5% SP and MA/PA with 5% SS have the complete criteriato selected as eutectic phase change materials (PCMs) compared toothers composition.

The melting temperature of MA/PA 5%SM, MA/PA 5%SP, andMA/PA 5%SS decreased by 5.37 C, 5.15 C, and 4.92 C, respec-tively. Whereas, the latent heat of fusions (DHf) of each eutecticsincreased by 23.69 J g1, 28.71 J g1, and 36.42 J g1, respectively.The results of these experiments indicated that the surfactant ad-ditives are very effective to optimize the thermal properties of MA/PA eutectic mixture. The current eutectic PCM has high latent heatwhen compared to other eutectic fatty acid mixtures, such ascapric/stearic acid [10], lauric/myristic acid, lauric/palmitic acid,myristic/stearic acid [18], myristic/palmitic acid, and palmitic/stearic acid[7].

Undercooling is the effect that a temperaturesignicantly belowthe melting temperature has to be reached before a material beginsto solidify and release heat (Fig. 7). If the temperature is notreached, the PCM will not solidify at all and thus only releasesensible heat[19]. The undercooling occurs is caused by differencein characteristics and composition of binary mixture components[17]. Thus, surfactant addition is needed to suppress undercooling.The addition of 5% SM, SP, and SS was able to decrease the tem-perature difference between the melting point and solidifyingpoint in binary mixture to 0.34 C, 0.4 C, and 0.82 C as shown inTables 2e4. This indicates that SM, SP, and SS were very effective in

Fig. 6. DSC curve thermal properties of MA/PA (7:3) and MA/PA (7:3) 5%SS.

Table 1

Thermal properties of MA/PA eutectic mixture measured by DSC analysis.

MA/PA (wt.%) Tm(C) DHm (J g1) Ts(C) DHs(J g

1)

0.0e100.0 63.08 173.69 61.90 172.9210.0e90.0 59.89 172.09 58.33 170.3520.0e80.0 56.43 181.00 54.61 176.8030.0e70.0 49.32 159.21 47.88 153.7040.0e60.0 47.95 154.29 45.26 153.5750.0e50.0 47.91 153.12 46.44 152.3260.0e40.0 47.08 151.72 50.73 151.1570.0e30.0 46.73 155.43 44.76 152.6480.0e20.0 49.81 154.57 45.67 150.3290.0e10.0 51.16 127.94 48.83 128.47100.0e0.0 54.70 161.37 52.58 161.14

Table 2

Thermal properties of MA/PA (70/30, wt.%) eutectic mixtures with SM.

Phase change materials(PCMs)

Tm(C) DHm(J g1) Ts(C) DHs(J g

1) DT(C)

MA/PA SM0% 46.73 155.43 44.76 152.64 1.97MA/PA SM5% 41.36 179.12 41.70 176.26 0.34MA/PA SM10% 46.05 188.98 42.13 187.04 3.92MA/PA SM15% 46.54 174.55 42.49 166.10 4.05MA/PA SM20% 51.82 182.44 46.32 176.02 5.5

Table 3

Thermal properties of MA/PA (70/30, wt.%) eutectic mixtures with SP.

Phase change materials(PCMs)

Tm(C) DHm(J g1) Ts(C) DHs(J g

1) DT(C)

MA/PA SP0% 46.73 155.43 44.76 152.64 1.97MA/PA SP5% 41.58 184.14 41.98 184.06 0.4MA/PA SP10% 43.51 181.28 42.88 179.57 0.63MA/PA SP15% 43.61 180.08 42.12 160.67 1.49

MA/PA SP20% 50.36 175.92 42.21 174.23 9.36

Table 4

Thermal properties of MA/PA (70/30, wt.%) eutectic mixtures with SS.

Phase change materials(PCMs)

Tm(C) DHm(J g1) Ts(C) DHs(J g

1) DT(C)

MA/PA SS0% 46.73 155.43 44.76 152.64 1.97MA/PA SS5% 41.81 191.85 41.00 188.06 0.81MA/PA SS10% 42.18 192.70 40.53 188.51 1.65MA/PA SS15% 43.42 191.65 40.16 190.66 3.26MA/PA SS20% 43.36 197.96 39.89 190.64 3.47

Fig. 7. Schematic temperature change during melting and solidication of a PCM with

undercooling[1].

H. Fauzi et al. / Applied Thermal Engineering 60 (2013) 261e265264

8/13/2019 Hadi Ate2013

5/5

decreasing the undercooling of MA/PA binary mixture as comparedto the binary mixture of MA/PA without surfactant addition.

Investigation of thermal properties of eutectic mixture MA/PAhave observed by other researchers in the literature, Kauranen, P.et al. [20] obtained eutectic composition ratio of MA/PA (59/41,wt.%), Tm 39.8 C and DHf174.0 J g

1. Furthermore, Sar [1] con-ducted eutectic composition ratio of these binary mixture (58/42,wt.%),Tm42.6 C and DHf169.7 J g

1. When comparing to thermalproperties in the previous literature to our results, the present MA/PA eutectic mixtures as shows inTables 2and3indicated that theyhave a better thermal properties with the addition of 5% SM,SP, andSS. The composition ratio of MA/PA eutectics component in this

study was difference to previous study caused by two factors: thecontent of impurities in the composition of eutectic mixture andthe rate of heat ow in the DSC measurement[21].

The important novelty was found in determining the thermalproperties of MA/PA eutectic mixture with addition of 5% SM, 5% SP,and 5% SS. It is potential to be applied as a heat storage material inthermal energy storage systems.

3.3. Thermal conductivity

Table 5shows the thermal conductivity of MA/PA (70/30, wt.%)and MA/PA (70/30, wt.%) with addition of 5% SM, 5% SP, and 5% SSsurfactants. The result indicated that adding surfactants increasedthe thermal conductivity of MA/PA eutectic mixture. Previous

studies were determined the thermal conductivity of parafn0.21 W m1 K1 [2,22,23]. Lane[5], prepared the organic eutecticmixture of blended naphthalene and benzoic acid (67.1/32.9 wt.%),the thermal conductivity of this eutectic PCM is 0.136 W m1 K1.Thus, the thermal conductivity of eutectic PCM obtained in thisstudy is better compared to other organic PCMs.

4. Conclusions

Eutectic phase change materials (PCMs) that have thermal char-acteristics appropriate to latent heat thermal energy storage (LHTES)applications have been identied. These eutectic PCMs were formu-lated by blending pure fatty acids, myristic acid (MA) and palmiticacid (PA), in a mass ratio of 70% myristic acid and 30% palmitic acid.Thermal properties and thermal conductivity of eutectic PCM weredetermined. Furthermore, the addition of acid-based surfactant so-dium myristate 5%, sodium palmitate 5%, and sodium stearate 5%showed a signicant effect on reduction of undercooling temperatureto 0.34 C, 0.4 C, and 0.81 C, and phase change transition tem-perature of eutectic PCM by 5.37 C, 5.15 C, 4.92 C, respectively.Whereas, the latent heat of fusion values and thermal conductivitiesof eutectic PCM were increased by 23.69 J g1, 28.71 J g1, 36.42 J g1,and 0.017 W m1 K1, 0.011 W m1 K1, 0.005 W m1 K1, respec-tively. Thus, the developed PCM in this study has a great potential tobe applied as heat storage materials in thermal energy storagesystems.

Acknowledgements

The authors acknowledge the Minister of Science, Technologyand Innovation Malaysia fornancial support through Science FundFunding, Ministry of Higher Education and University Malayathrough High Impact Research grant (UM.R/HIR/MOHE/ENG/21-D000021-16001) and University of Malaya Research Grant No.UMRG RP021-2012A.

References

[1] A. Sar, Thermal reliability test of some fatty acids as PCMs used for solarthermal latent heat storage applications, Energy Conversion and Management44 (14) (2003) 2277e2287.

[2] A. Abhat, Low temperature latent heat thermal energy storage: heat storagematerials, Solar Energy 30 (4) (1983) 313e332.

[3] M.M. Farid, A.M. Khudhair, S.A.K. Razack, A review on phase change energystorage: materials and applications, Energy Conversion and Management 45(9e10) (2004) 1597e1615.

[4] B. Zalba, J.M. Marin, L.F. Cabeza, H. Mehling, Review on thermal energy storagewith phase change: materials, heat transfer analysis and applications, AppliedThermal Engineering 23 (3) (2003) 251e283.

[5] G.A. Lane, Low temperature heat storage with phase change materials, In-ternational Journal of Ambient Energy 1 (3) (1980) 155e168.

[6] D. Zhou, C.Y. Zhao, Y. Tian, Review on thermal energy storage with phasechange materials (PCMs) in building applications, Applied Energy 92 (0)(2012) 593e605.

[7] A. Sar, H. Sar, A. nal, Thermal properties and thermal reliability of eutecticmixtures of some fatty acids as latent heat storage materials, Energy Con-version and Management 45 (3) (2004) 365e376.

[8] A. Sar, Eutectic mixtures of some fatty acids for latent heat storage: thermalproperties and thermal reliability with respect to thermal cycling, EnergyConversion and Management 47 (9e10) (2006) 1207e1221.

[9] A. Karaipekli, A. Sar, K. Kaygusuz, Thermal properties and long-term reli-ability of capric acid/lauric acid and capric acid/myristic acid mixtures forthermal energy storage, Energy Sources, Part A: Recovery, Utilization, andEnvironmental Effects 30 (13) (2008) 1248e1258.

[10] A. Karapekl, A. Sar, K. Kaygusuz, Thermal properties and thermal reliabilityof capric acid/stearic acid mixture for latent heat thermal energy storage,Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 31(3) (2009) 199e207.

[11] D. Rozanna, T.G. Chuah, A. Salmiah, T.S.Y. Choong, M. Saari, Fatty acids asphase change materials (PCMs) for thermal energy storage: a review, Inter-

national Journal of Green Energy 1 (4) (2005) 495e513.[12] A. Sar, A. Karaipekli, Preparation and thermal properties of capric acid/pal-mitic acid eutectic mixture as a phase change energy storage material, Ma-terials Letters 62 (6e7) (2008) 903e906.

[13] A.S.K. Kaygusuz, Thermal energy storage system using some fatty acids aslatent heat energy storage materials, Energy Sources 23 (3) (2001) 275e285.

[14] F.O. Cedeo, M.M. Prieto, A. Espina, J.R. Garcia, Measurements of temperatureand melting heat of some pure fatty acids and their binary and ternarymixtures by differential scanning calorimetry, Thermochimica Acta 369 (1e2)(2001) 39e50.

[15] D. Feldman, M.M. Shapiro, D. Banu, C.J. Fuks, Fatty acids and their mixtures asphase-change materials for thermal energy storage, Solar Energy Materials 18(3e4) (1989) 201e216.

[16] A. Sar, Thermal characteristics of a eutectic mixture of myristic and palmiticacids as phase change material for heating applications, Applied ThermalEngineering 23 (8) (2003) 1005e1017.

[17] T. Matsui, M. Yoshida, H. Yamasaki, Y. Hatate, Thermal properties of multi-component fatty acids as solideliquid phase change materials for coolingapplications, Chemical Engineering Communications 194 (1) (2007) 129e139.

[18] A. Sar, Eutectic mixtures of some fatty acids for low temperature solarheating applications: thermal properties and thermal reliability, AppliedThermal Engineering 25 (14e15) (2005) 2100e2107.

[19] H. Mehling, L. Cabeza, Basic thermodynamics of thermal energy storage, in:Heat and Cold Storage with PCM, Springer, Berlin, Heidelberg, 2008, pp. 1e10.

[20] P. Kauranen, K. Peippo, P.D. Lund, An organic PCM storage system withadjustable melting temperature, Solar Energy 46 (5) (1991) 275e278.

[21] H. Bo, E.M. Gustafsson, F. Setterwall, Tetradecane and hexadecane binarymixtures as phase change materials (PCMs) for cool storage in district coolingsystems, Energy 24 (12) (1999) 1015e1028.

[22] A. Sar, A. Karaipekli, Thermal conductivity and latent heat thermal energystorage characteristics of parafn/expanded graphite composite as phasechange material, Applied Thermal Engineering 27 (8e9) (2007) 1271e1277.

[23] D. Zhou, C.Y. Zhao, Experimental investigations on heat transfer in phasechange materials (PCMs) embedded in porous materials, Applied ThermalEngineering 31 (5) (2011) 970e977.

Table 5

Effectof surfactant additives to thermal conductivity of MA/PA (70/30, wt.%) eutecticmixture.

Phase change materials(PCMs)

Thermal conductivity(W m1 K1)

Temperature (C)

MA/PA 0.225 30.19 (solid)MA/PA 5%SM 0.242 29.35 (solid)MA/PA 5%SP 0.236 29.85 (solid)

MA/PA 5%SS 0.230 29.60 (solid)

H. Fauzi et al. / Applied Thermal Engineering 60 (2013) 261e265 265

http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1http://refhub.elsevier.com/S1359-4311(13)00475-4/sref2http://refhub.elsevier.com/S1359-4311(13)00475-4/sref2http://refhub.elsevier.com/S1359-4311(13)00475-4/sref2http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref4http://refhub.elsevier.com/S1359-4311(13)00475-4/sref4http://refhub.elsevier.com/S1359-4311(13)00475-4/sref4http://refhub.elsevier.com/S1359-4311(13)00475-4/sref4http://refhub.elsevier.com/S1359-4311(13)00475-4/sref4http://refhub.elsevier.com/S1359-4311(13)00475-4/sref5http://refhub.elsevier.com/S1359-4311(13)00475-4/sref5http://refhub.elsevier.com/S1359-4311(13)00475-4/sref5http://refhub.elsevier.com/S1359-4311(13)00475-4/sref5http://refhub.elsevier.com/S1359-4311(13)00475-4/sref6http://refhub.elsevier.com/S1359-4311(13)00475-4/sref6http://refhub.elsevier.com/S1359-4311(13)00475-4/sref6http://refhub.elsevier.com/S1359-4311(13)00475-4/sref6http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref13http://refhub.elsevier.com/S1359-4311(13)00475-4/sref13http://refhub.elsevier.com/S1359-4311(13)00475-4/sref13http://refhub.elsevier.com/S1359-4311(13)00475-4/sref13http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref19http://refhub.elsevier.com/S1359-4311(13)00475-4/sref19http://refhub.elsevier.com/S1359-4311(13)00475-4/sref19http://refhub.elsevier.com/S1359-4311(13)00475-4/sref19http://refhub.elsevier.com/S1359-4311(13)00475-4/sref20http://refhub.elsevier.com/S1359-4311(13)00475-4/sref20http://refhub.elsevier.com/S1359-4311(13)00475-4/sref20http://refhub.elsevier.com/S1359-4311(13)00475-4/sref21http://refhub.elsevier.com/S1359-4311(13)00475-4/sref21http://refhub.elsevier.com/S1359-4311(13)00475-4/sref21http://refhub.elsevier.com/S1359-4311(13)00475-4/sref21http://refhub.elsevier.com/S1359-4311(13)00475-4/sref21http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref23http://refhub.elsevier.com/S1359-4311(13)00475-4/sref23http://refhub.elsevier.com/S1359-4311(13)00475-4/sref23http://refhub.elsevier.com/S1359-4311(13)00475-4/sref23http://refhub.elsevier.com/S1359-4311(13)00475-4/sref23http://refhub.elsevier.com/S1359-4311(13)00475-4/sref23http://refhub.elsevier.com/S1359-4311(13)00475-4/sref23http://refhub.elsevier.com/S1359-4311(13)00475-4/sref23http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref22http://refhub.elsevier.com/S1359-4311(13)00475-4/sref21http://refhub.elsevier.com/S1359-4311(13)00475-4/sref21http://refhub.elsevier.com/S1359-4311(13)00475-4/sref21http://refhub.elsevier.com/S1359-4311(13)00475-4/sref21http://refhub.elsevier.com/S1359-4311(13)00475-4/sref20http://refhub.elsevier.com/S1359-4311(13)00475-4/sref20http://refhub.elsevier.com/S1359-4311(13)00475-4/sref20http://refhub.elsevier.com/S1359-4311(13)00475-4/sref19http://refhub.elsevier.com/S1359-4311(13)00475-4/sref19http://refhub.elsevier.com/S1359-4311(13)00475-4/sref19http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref18http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref17http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref16http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref15http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref14http://refhub.elsevier.com/S1359-4311(13)00475-4/sref13http://refhub.elsevier.com/S1359-4311(13)00475-4/sref13http://refhub.elsevier.com/S1359-4311(13)00475-4/sref13http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref12http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref11http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref10http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref9http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref8http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref7http://refhub.elsevier.com/S1359-4311(13)00475-4/sref6http://refhub.elsevier.com/S1359-4311(13)00475-4/sref6http://refhub.elsevier.com/S1359-4311(13)00475-4/sref6http://refhub.elsevier.com/S1359-4311(13)00475-4/sref6http://refhub.elsevier.com/S1359-4311(13)00475-4/sref5http://refhub.elsevier.com/S1359-4311(13)00475-4/sref5http://refhub.elsevier.com/S1359-4311(13)00475-4/sref5http://refhub.elsevier.com/S1359-4311(13)00475-4/sref4http://refhub.elsevier.com/S1359-4311(13)00475-4/sref4http://refhub.elsevier.com/S1359-4311(13)00475-4/sref4http://refhub.elsevier.com/S1359-4311(13)00475-4/sref4http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref3http://refhub.elsevier.com/S1359-4311(13)00475-4/sref2http://refhub.elsevier.com/S1359-4311(13)00475-4/sref2http://refhub.elsevier.com/S1359-4311(13)00475-4/sref2http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1http://refhub.elsevier.com/S1359-4311(13)00475-4/sref1