Selection of the Appropriate Phase Change Material for Two Innovative Compact Energy Storage Systems in Residential Buildings

Abstract

The implementation of thermal energy storage systems using phase change materials to support the integration of renewable energies is a key element that allows reducing the energy consumption in buildings by increasing self-consumption and system efficiency. The selection of the most suitable phase change material is an important part of the successful implementation of the thermal energy storage system. The aim of this paper is to present the methodology used to assess the suitability of potential phase change materials to be used in two innovative energy storage systems, one of them being mainly intended to provide cooling, while the other provides heating and domestic hot water to residential buildings. The selection methodology relies on a qualitative decision matrix, which uses some common features of phase change materials to assign an overall score to each material that should allow comparing the different options. Experimental characterization of the best candidates was also performed to help in making a final decision. The results indicate some of the most suitable candidates for both systems, with RT4 being the most promising commercial phase change material for the system designed to provide cooling, while for the system designed to provide heating and domestic hot water, the most promising candidate is RT64HC, another commercial product.

Performance Study of Direct Integration of Phase Change Material into an Innovative Evaporator of a Simple Vapour Compression System

“…The thermo-physical properties as provided by the manufacturer are provided in the Table 2. To determine the specific enthalpy of the PCM, DSC 3+ Mettler Toledo equipment with ±0.2 K accuracy available in GREiA research group at university of Lleida was used [19]. From the results shown in Figure 6 the phase change temperature was found to be around 5 °C.…”

“…From the results shown in Figure 6 the phase change temperature was found to be around 5 °C. (adapted from [19]).…”

“…. DSC results of heat flow in charging and discharging of the commercial PCM RT4 (adapted from [19]).…”

Experimental Devices to Investigate the Long-Term Stability of Phase Change Materials under Application Conditions

“…Phase change materials (PCM) can store large amounts of thermal energy in a small temperature range around their phase change temperature. Therefore, latent heat storage systems based on PCM can provide high thermal energy storage densities [1][2][3][4]. An important prerequisite to select a reliable phase change material (PCM) for thermal energy storage applications is to investigate its stability under application conditions.…”

“…RT = room temperature, 2 without supercooling of SAT, 3 max. bath volume,4 at 200 l•h −1 , 5 PCS in contact with water.…”