Thermal Energy Storage Using Latent Heat of Phase Change Materials

The major energy consumption comes from buildings and there is about 40% energy consumption from air conditioner (AC) units. In this study, the objective is to reduce cooling load from AC units during peak periods, by utilizing thermal energy storage (TES) unit, via latent thermal storage, implementing a phase change material (PCM). A phase change composite (PCC) has been fabricated, which is capable of storing cold with an increased thermal conductivity using a graphite matrix and an organic low melting PCM. To verify and validate the performance of the fabricated PCC material, a TES unit was built with the phase change composite to compare with existing TES units from conventional phase change materials. Experiments were performed to test the functioning of the TES units on varying rates of cold discharge. In addition, finite element analysis (FEA) on the TES unit was carried out. Key factors that affect performance such as surface area, thermal conductivity and geometry of the TES, were identified through the numerical analysis and experimental tests. After that, a commercially successful ice TES prototype unit and a PCC TES prototype unit were developed with design optimization carried out to compare the performance of the TES units. Finally, with equal performance rates, a cost analysis was carried out to evaluate the two TES technologies.