Advantages of using Microencapsulated Phase Change Slurries as a heat storage medium in domestic hot water systems

Microencapsulated Phase Change Slurries (PCSs) are a promising solution to be employed as storage media. The Phase Change Material (PCM) core allows a large amount of energy to be stored due to the latent heat, while maintaining the fluidity of the medium under all operating conditions. Recently, PCSs have been proposed as a thermal energy storage medium in HVAC systems, as they potentially reduce the required storage volume and the associated heating capacity due to a peak-shaving effect. In this perspective, this work investigates the benefits of using PCSs as thermal storage media in a typical domestic hot water (DHW) system. The energy model uses experimental data to evaluate the convective heat transfer coefficient occurring in the submerged coils of a PCS tank. For a reference heat load, the results show that storage volume and thermal losses can be reduced by about 3 times compared to water. The results demonstrate the potential of PCSs to facilitate the adoption of thermal storages and, in turn, to allow the use of low-capacity generators, such as heat pumps, in those applications that require high-capacity and intermittent energy services (e.g., DHW), and to introduce flexibility in the generator activation profile.