Study On The Performance Of Phase Change Material Combined With Building Envelop For Cold Storage

Phase change material (PCM) used in the building not only can decrease the indoorthermal environment fluctuations, but also reduce the building energy consumptionthrough absorbing surplus heat/cold and releasing the heat/cold in need. The studyaims to research a new type of passive PCM cold storage system combined withbuilding envelops. Objectives of the study included the development of new PCM,encapsulation, the methods to combine with building envelops, the experiment of coldstorage, and the establishment of heat-transfer model.This research has developed a series of high latent heat PCMs that is workable forthe temperate continental monsoon climate of China, based on the testing instrumentof differential scanning calorimetry (DSC) and the raw materials of higher fatty acidand high alcohols. A new kind of form-stable PCM has been prepared in this study,which was supported and stabilized by high polymer materials (HDPE and EVA), andwhose thermal conductivity was enhanced by aluminum powder. Tests have beenconducted to verify the properties of form-stable PCM, namely, leakage test, SEMtest, infrared spectrum test, DSC test, enhancement test of heat releasing/absorbingefficiency. Another encapsulating method, PCM panel, has been researched. ThePCMs were firmly and securely contained in the PCM panel without leakage. Finswere fixed in the internal structure to strengthen the panel and increase the efficiencyof heat releasing/absorbing. Three full-scale perforated brick test rooms were built totest the cold storage performance. Two systems: PCMOW-PCM panel combined withthe outside surface of building envelop, and PCMIW-PCM panel combined with theinside surface of building envelop, were conducted in the two rooms, and theremaining room was the reference with no PCMs. Three strategies were adopted inthe test, including free cooling, open window and door in night and forced ventilationin night.Results have been compared in the analysis process. It was found that, free coolingstrategy had a worse-performing and the results of the two strategies of open windowand door in night and forced ventilation in night showed almost the same level, butthe strategy of forced ventilation in night consumed energy for air exhauster. It is concluded that open window and door in night is the best strategy. Compared thePCMOW and PCMIW system, PCMIW showed a better cold storage performance inall the three strategies, and the indoor temperatures of both PCMOW and PCMIWwere lower than that of reference. Based on the measured value, the heat-transfermodel of PCM building envelops were established, which has been verified at last.