PREPARATION and PERFORMANCE of COMPOSITE BUILDING MATERIALS with PHASE CHANGE MATERIAL for THERMAL STORAGE

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Energy (2017) 000–000 125–130 EnergyProcedia Procedia143 00 (2017) www.elsevier.com/locate/procedia

World Engineers Summit – Applied Energy Symposium & Forum: Low Carbon Cities & Urban Energy Joint Conference, WES-CUE 2017, 19–21 July 2017, Singapore

PREPARATION and PERFORMANCE of COMPOSITE The 15th International Symposium on District Heating and Cooling BUILDING MATERIALS with PHASE CHANGE MATERIAL for Assessing the feasibility of using the heat demand-outdoor THERMAL STORAGE temperature forecast a,b, function for a,b a long-term a,b district a,cheat demand a,d e a

Qunli Zhang *, Yang Rao , Yuqing Jiao , Liyan Li ,Yinlong Li , Liwen Jin a,b,c a a b c c I. Andrić A. Pina , P. Ferrão J. Air Fournier .,Engineering, B. Lacarrière , O. Le Corre Beijing Municipal Key Lab *, of Heating, Gas Supply, Ventilating,and Conditioning Beijing 2011 Collaborative Innovation

Center of energy conservation and emission reduction, Beijing University of Civil Engineering and Architecture, Beijing 100044, China; a IN+ Center for Innovation, Technology and Policy Research InstitutoUniversity Superior of Técnico, Av. Roviscoand PaisArchitecture, 1, 1049-001 Xicheng Lisbon, Portugal Beijing Advanced Innovation Center For Future Urban Design,-Beijing Civil Engineering District, b Veolia Recherche & Innovation, 291100044, Avenue Dreyfous Beijing China; Daniel, 78520 Limay, France c c Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France Département Systèmes China Architecture Design ＆ Research Group, Beijing 100048, China d SINOPEC Engineering Incorporation, Beijing 100101, China dGroup of Building Environment and Sustainability Technology, Building Environment and Equipment Engineering, Xi’an Jiaotong University, Xi’an and 710049,China Abstract eGroup of Building Environment and Sustainability Technology, Building Environment and Equipment Engineering, Xi’an Jiaotong University, Xi’an and 710049,China b

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, Abstract prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand The polyethylene glycol (PEG-1000) wasinselected phase change material and The the expanded (EP), forecast. The district of Alvalade, located Lisbon as (Portugal), was used as a (PCM) case study. district is perlite consisted of 665 the granular carbon（GAC）, the powdered activated and(low, the expanded graphite buildings thatactivated vary in both construction period and typology. Three carbon weather(PAC) scenarios medium, high) and (EG) three were district selected as porous materials. The composite phase change material was prepared by thevalues physical renovation scenariosadsorption were developed (shallow, intermediate, deep). To estimate the(CPCM) error, obtained heat demand were adsorption method. composite changemodel, materials compound with and the validated polyethylene and the compared with resultsThe from a dynamicphase heat demand previously developed by theglycol authors. The resultsgraphite showed were that when only change is analyzing considered,the the adsorption margin of error couldof besuch acceptable for some applications expanded picked byweather comparing and capacity four types of porous (the error And in annual was lower than 20% for allfor weather scenarios afterand introducing renovation materials. then demand the composite building material thermal storageconsidered). mixed withHowever, the CPCM the cement, scenarios, the error increased to 59.5% (depending on the weather andof renovation scenarios considered). water-reducer, earlyvalue strength agentupwas prepared in the pressure condition -0.05Mpa and thecombination constant temperature The valueofof70℃. slope Its coefficient on average the within the range of 3.8% upthe to compression 8% per decade, that corresponds to the condition thermal increased physical properties, structural stability and resistance capability in quality the number of heating hours of were 22-139h during the heating seasonThe (depending on thethat combination of weather and ofdecrease different proportion specimens experimental researched. results show such composite renovation scenarioswith considered). On the other hand, function interceptconductivity, increased for large 7.8-12.7% decade (depending on the building materials CPCM appears light density, high thermal heat per storage capacity and good coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and stability, and its compression resistance capability can satisfy the requirement of ordinary mortar building material. improve the accuracy of heat demand estimations. © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. * Corresponding author. Tel.: 13522898182; E-mail address: [email protected] Keywords: Heat demand; Forecast; Climate change

1876-6102 © 2017 The Authors. Published by Elsevier Ltd.

Peer-review under responsibility of the scientific committee of the World Engineers Summit – Applied Energy Symposium & Forum: Low Carbon Cities & Urban Energy Joint Conference. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the World Engineers Summit – Applied Energy Symposium & Forum: Low Carbon Cities & Urban Energy Joint Conference. 10.1016/j.egypro.2017.12.659

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Qunli Zhang/ Energy Procedia 00 (2017) 000–000 Qunli Zhang et al. / Energy Procedia 143 (2017) 125–130

© 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the World Engineers Summit – Applied Energy Symposium & Forum: Low Carbon Cities & Urban Energy Joint Conference. Keywords: polyethylene glycol; expanded graphite; phase change material; thermal storage; building material.

1. Introduction The phase change material (PCM) has larger thermal storage capacity during its smaller phase transition temperature range. The PCM applied in building material can improve its thermal storage capacity during its phase transition temperature range and reduce building operation energy consumption [1]. Yan prepared cement wallboard with paraffin/high density polyethylene (HDPE) composite PCM and cement paste. Compared with ordinary wallboard, the thermal storage cement wallboard shows smaller thermal fluctuations, the building component with shape-stabilized phase change material for thermal storage shows well thermal performance and thermal insulation properties [2]. Zhang Ni mixed octodecane/expanded graphite and Portland cement to prepare cement wallboard with composite PCM with different quality content for thermal storage [3]. Xia Li tested regenerative properties and exothermic properties for paraffin/expanded graphite composite PCM, the result show that expanded graphite can significantly improve the thermal storage rate and heat release rate for composite PCM [4]. Xia Wei proposed a kind of flooring heating system with shape-stabilized composite PCM for thermal storage combined with solar energy collector. The feasibility study shows that the heating system shows well safety and reliability performance, well thermal comfort performance and application prospect [5].. Zhou Guobin separately combined capillary network and floor heating polyethylene pipe with sand and PCM applied to hydraulic floor heating system[6]. Zhang Yinping used low-density polyethylene, high-density polyethylene as packaging materials, paraffin as PCM, to prepare shape-stabilized PCM applied to electrical floor heating system with PCM for thermal storage[7]. This paper mainly tests the thermal performance of composite building materials with PCM for thermal storage. 2. Experiment materials and instruments Experiment materials: the polyethylene glycol (PEG-1000), expanded perlite (EP), granular activated carbon (GAC), powdered activated carbon (PAC), expanded graphite (EG), cetyl trimethyl ammonium bromide, gumacabic powder, sodium dodecyl benzene sulfonate, Portland cement, normal sand, water-reducer, early strength agent. Experiment instruments: water bath, vacuum drying oven, low temperature box, Electric-liquid pressure tester, thermal conductivity analyzer. 3. The selection and preparation of the composite PCM 3.1. Test method Compared with other preparation method of PCM, the negative pressure adsorption has advantages of easy preparation, low cost and easy to promote application. This paper mixed PEG-1000 with EG, EP, GAC and PAC to prepare composite PCM under certain pressure by the negative pressure adsorption. In order to study the absorption rate of PCM, a appropriate amount experimental sample is heated in the vacuum drying oven at 70℃ for 1h. The experimental sample is weighed after drying and the absorption rate of PCM can be calculated. The test result is the average value of three calculated values. Absorption rate of PCM characterize the adsorption capacity of porous materials, equals to phase change materials quality percentage of porous materials in composite phrase change materials, the formula is: m - m1 ´ 100% f= 2 m1 Where: φ is absorption rate; m1 is the porous substrate material quality, g; m2 is the porous substrate material quality after adsorption phase change materials.



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3.2. The research on absorption rate 3.2.1 The effect of adsorption temperature This part analysis the absorption rate of composite PCM under testing condition of absorption temperature at 40 ℃, 50℃, 60℃, 70℃, absorption pressure at atmospheric pressure and adsorption time at 60min. The result is shown in Fig.1. The adsorption capacity of four porous materials increase with the adsorption temperature rising. Under the adsorption temperature at 70 ℃, the adsorption quantity of expanded graphite is the largest, followed by expanded perlite, powdered activated carbon, granular activated carbon. 3.2.2 The effect of adsorption time This part analysis the absorption rate of composite PCM under testing condition of absorption time at 10min, 30min, 60min, 120min, absorption pressure at atmospheric pressure and adsorption temperature at 70℃. The result is shown in Fig.1 (b). 3.2.3 The effect of adsorption pressure This part analysis the absorption rate of composite PCM under testing condition of absorption pressure at atmospheric pressure, -0.1 MPa and -0.05MPa, adsorption time at 10min and 30min and adsorption temperature at 70℃. The result is shown in Fig.1 (c) and (d). It can be seen that under the condition of negative pressure for 10 min, it can make close to the saturated porous materials. Powdered activated carbon under the negative pressure for a long time, it’s porous structure change, made the phase change materials bleed out.

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Fig.1 (a) Variation curve of absorption rate at different temperature; (b) Variation curve of absorption rate at different time; (c) Variation curve of absorption rate at different pressure in 10 minutes; (d) Variation curve of absorption rate at different pressure in 30 minutes

3.2.4 The effect of surfactant For the reason that the adsorption capacity of GAC well below other three porous materials, this part analysis the absorption rate of other three composite PCM under testing condition of different surfactants with the same quality percent (1wt%), absorption pressure at atmospheric pressure, adsorption time at 30min and adsorption temperature at 70℃. The three kinds of surfactants were cetyl trimethyl ammonium bromide, Arabian trees powder and sodium dodecyl benzene sulfonic acid, as shown in Fig.2. Summary, expanded graphite has the highest adsorption rate. This paper used expanded graphite as porous material and the preparation method of composite PCM is negative pressure adsorption in the constant temperature drying oven for 10 minutes at pressure of -0.05Mpa and temperature of 70℃.

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3.3. The thermal physical properties of composite PCM 3.3.1 The latent heat and phase transition temperature The phase transition temperature and latent heat of the composite PCM with mass fraction of 0%-10% were measured by differential scanning calorimeter (DSC). The results were shown in Fig.3. 180 160

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The thermal conductivity of composite PCM increases with the expanded graphite, but will reduce the latent heat of the composite PCM. Considering the thermal conductivity of composite PCM and heat storage capacity, the mass content of expansion graphite at 8% has better physical performance. 3.3.2The structural stability The polyethylene glycol/expanded graphite (8% mass fraction) composite PCM is placed in a constant temperature environment of 10℃ and 70℃ for 100 times, and the mass loss of the composite PCM is 4.5% after 100 cycles, performing good structural stability. 4. The preparation and thermal performance of composite building materials with PCM for thermal storage 4.1. The preparation of the building material with PCM for thermal storage This paper used the composite PCM to replace the standard sand to prepare building materials. The composite PCM incorporation ratio X (expressed as a percentage compared with the quality of cement) is: 0.7, 0.8, 0.9, 1.0. The PCM mortar is prepared according to the mass ratio of cement, composite phase change materials, water reducing agent, early strength agent equal to 1:X:0.8~1:0.005:0.02. The water reducer and early strength agent can accelerate solidification. This paper used artificial mixing (5-10min) in the preparation process. Mixing the phase change composite cement mortar into the 70.7mm×70.7mm×70.7mm standard triple mold and the 100 mm×100mm×40mm own molds to prepare phase change energy storage cement block and the phase change energy storage cement plates after mixture. The phase change energy storage cement plates are used for testing physical performance and structural stability, while the phase change energy storage cement block is used for testing compressive strength. The phase change concrete components numbers in Table1. Table 1. The numbers of the phase change concrete components



Qunli Zhang et al. / Energy Procedia 143 (2017) 125–130 Qunli Zhang / Energy Procedia 00 (2017) 000–000 The numbers of the cement plates Samples size Mixing proportion The numbers of the cement blocks Samples size Mixing proportion

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4.2. The testing method of the building material with PCM for thermal storage The apparent density means the mass of the unit apparent volume material under natural state. Repeat five measurements, the results is the average value of the five measurements. This paper uses the transient hot wire method to determine the thermal conductivity of the phase change energy storage cement plates. Repeat five measurements, the results is the average value of the five measurements. This paper uses T-History method to test phase transition temperature and latent heat [8]. Repeat three measurements, the results is the average value of the three measurements. This paper uses the mass loss method to evaluate the structure stability of the phase change energy storage plate. Add different quality of the composite phase change material to the composite phase change energy storage plates, then cycle them in 70 degree and 5 degree in the environment, each heat storage process is greater than 30 min, measure the mass loss of the composite phase change energy storage plates after 0times, 25times, 50times, 75times, 100 times freezing—melting cycle. Repeat five measurements, the results is the average value of the five measurements. Compressive strength test use the measured 70.7mm× 70.7mm×70.7mm cement mortar block, the same proportion of sample six as a group, determination of the arithmetic mean value for the test results, exclude test value more than the average of + 10% results, the remaining values take the arithmetic mean value, if there is more than the average of + 10%results, then do the experiment one more time. 4.3. The physical properties of the building material with PCM for thermal storage 4.3.1 The apparent density The apparent density of the composite building materials with PCM for thermal storage decreases linearly with the increase of the proportion of the composite PCM. The main reason is that the density of the composite PCM is much less than that of the cement and standard sand. 4.3.2 The thermal conductivity The thermal conductivity of the composite building materials with PCM for thermal storage increases linearly with the increase of the proportion of the composite PCM. The thermal conductivity of the composite PCM is 2.719 W/(m•k). 4.3.3 The phase transition temperature and latent heat

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The phase transition temperature and latent heat of the composite building materials with PCM for thermal storage is shown in Fig. 4 (a). The initial temperature and the phase transition temperature of the phase change are

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smaller. The latent heat of the composite building materials with PCM for thermal storage increases with the increase of the composite phase change material. 4.4. The structural stability of the building material with PCM for thermal storage The surface condition of the composite building materials with PCM for thermal storage is shown in Fig.15. The composite phase change energy storage samples have no cracks caused by the volume expansion and contraction. After 100 times of solidification and melting cycle process, sample 5# quality change is larger, unsuitable for building materials. The other energy storage plate has better structure stability, can be used as building materials, as shown in Fig.4 (b). The compressive strength of the composite building materials with PCM for thermal storage decreases linearly with the increase of the proportion of the composite PCM. When the percentage of cement and composite phase change material is greater than 1:0.9, the compressive strength is greater than 0.3 MPa, and the phase change material can be used to meet the basic requirements of ordinary mortar. 5. Conclusions (1) The expanded graphite expansion to granular activated carbon, powdered activated carbon and expanded perlite has better adsorption capacity and thermal conductivity, suitable as porous material for composite PCM. The preparation condition of polyethylene glycol / expanded graphite composite PCM is prepared in constant temperature drying box of adsorption pressure at -0.05 MPa, adsorption temperature at 70℃ and adsorption time at 10 min, the adsorption rate can reach 1849.5%. (2) The composite building materials with PCM for thermal storage has smaller apparent density, better thermal conductivity and larger thermal storage capacity after applied PCM in building materials. Under this experiment condition, the apparent density can be reduced by 15.6%~22.7%, the thermal conductivity can be increased by9.2%~106.3%, and the thermal conductivity increases linearly with the increase of composite PCM mixing proportion. The composite building materials with PCM for thermal storage have stable phase transition temperature and high heat storage capacity. (3) The compressive strength of the specimens can be greatly reduced by the addition of the composite PCM. In order to satisfy the purpose that the compressive strength of composite building materials with PCM for thermal storage should be greater than 0.3 MPa, the quality of cement and composite PCM should be greater than 1:0.9. The composite building materials with PCM for thermal storage have good structural stability. After 100 cycles of solidification and melting cycle, there is no crack on the surface of each sample. References [1] Wang Yi, Yang Rui, Zhang Yinping, Wang Xin. Recent process in shape-stabilized phase change materials [J]. Energy Storage Science and Technology. 2013,7,2(4):362-368 [2] Yan Q, Li L, Liang C. Thermal performance of shape-stabilized phase change paraffin wallboard [J]. Sustain Energy, 2010, 29(4): 185-190. [3] Zhang Ni, Fang Xiaoming, Zhang Zhengguo. Study on the thermal properties of cement boards based on composite phase change materials [J]. New Chemical Materials, 2012,3:41 [4] Xia Li, Zhang Peng, Zhou Yuan, Wang Ruzhu. Study of the charging/discharging characteristics of paraffin and paraffin/expanded graphite composite material [J]. Acta Energiae Solaris Sinica, 2010,5:610 [5] Xiao Wei, Wang Xin, Zhang Yinping. Thermal analysis on shape-stabilized PCM panel as partition walls for energy storage in winter [J]. Journal of Engineering Thermophysics, 2011,32(1):123-125 [6] He Jing, Zhou Guobin, Feng Zhizheng, Yang Laishun. Experimental investigation on floor radiant heating using capillary mat and phase change materials for energy storage [J]. Acta Energiae Solaris Sinica, 2013,10,34(10):1802-1809 [7] Zhang Y P, Wang X, Cheng R. Phase change energy storage building envelope: A review for our research. The 4th International Symposium on Heat Transfer and Energy Conservation. Beijing: China Architecture and Building Press, 2012:21-28. [8] Li Cuimin, Zhao Jianing. Experiment study on thermal storage performance improvement of capric acid [J]. Acta Energiae Solaris Sinica, 2011,12:1833