Concept development and experimentation of a Phase Change Material (PCM) enhanced domestic hot water

In this study, a new lower cost Phase Change Material “PCM” has been developed and valued which will reduce the financial costs related to the domestic hot water system “DHW”. PCM mixture composed of animal fat and paraffin wax was thermally characterized, and integrated into a conventional DHW electric heater to enhance its energy performance. Using the differential scanning calorimetry (DSC) device, the melting range for this new PCM ranged between 35.58 °C and 62.58 °C with a latent heat of fusion between 180 and 210 kJ/kg, making the mixture ideal for DHW use. The new assembled PCM-embedded water tank was experimentally tested in the lab under different operation regimes to evaluate its technical and economic feasibility. Several parameters have been analyzed, including the produced hot water volume, savings in energy consumption, and the associated energy cost. The experimental results indicated that the PCM-enhanced water tank may produce one-third to two times more hot water than the conventional water tank, depending on the thermostat setpoints. In addition, this tank was found to reduce the energy cost by 3.94% and 56.88% at 50 °C and 75 °C, respectively, suggesting that the PCM-enhanced tank should be operated at a higher setpoint to achieve maximum cost benefits.