Experimental study of a PCM storage system integrated with a thermal solar collector

Abstract

Recently, phase change materials (PCM) have become widely used in thermal storage systems for both industrial and domestic applications. These materials have good thermal properties, like thermal capacity and phase change temperature, however low thermal conductivity and high viscosity limits their heat transfer coefficient. This paper experimentally investigates the execution of a water-PCM storage system integrated with a flat plate solar collector. Paraffin wax is used as the PCM material and is packed in small cylindrical aluminum containers and accommodated in a hot water tank. In this study, an experimental test facility was designed and built and experiments were carried out in the City of Kerbala in Iraq. The study includes two different heat source types, namely a flat-plate solar collector and an electrical heater element. Experimental results show that the proposed configuration with the PCM material can produce hot water with up to 9.5 °C higher than that of the basic warm water storage system. In the case of the flat plate solar collector, the water remained hot, at about 28.5 °C more than the surrounding temperature during the solar system tests. This study highlights the potential of using PCM materials in heat storage systems and thermal solar energy.

Numerical Analysis on Hot Water Storage Tank Integrated With Phase Change Materials

“…As it is shown in previous studies, there are still discrepancies on the results conducted by different researchers on the benefits of incorporating PCMs into SDWHS [20]. Hence, this study reports the outcome of the numerical simulations through ANSYS Fluent on the application of encapsulated PCMs in a water-PCM storage system, which has been validated against experimental results conducted by Shareef et al [21]. The model assumes a forced circulation, to obtain a well-defined mass-flow rate through the entire system.…”

“…The PCM containers were located into two rows of 16 containers each, and the volume of each container is 0.3 litres. It is important to note that although the majority of the dimensions were obtained from the study conducted by Shareef et al [21], some of the dimensions were not included; thus, the geometries are not exactly the same.…”

“…The initial conditions of both water and the temperature of the PCM were assumed to be 24°C. Thermal losses were considered in the model as convection losses in the external walls, the ambient temperature was set to 20°C [21], and the heat transfer coefficient of the wall was set as 7.5 W/m 2 K. The volume flow rate during the charging period was set to 1L/min. The inlet temperature was calculated based on the useful heat (Qu) provided in the referenced experimental study [21].…”

“…CFD numerical simulations of the two models of the hot water storage tank with and without the PCM containers filled with paraffin wax (melting temperature 44°C) were conducted to analyse and compare the heat transfer performance of the tank. To validate the numerical model developed the results were compared against the experimental data obtained from the research studied conducted by Shareef et al [21]; the validation of the model will allow the CFD model to be further investigated. Fig.…”

“…Fig. 3(a) provides with the average water temperature profile inside the hot water storage tank obtained from the numerical and experimental results [21] during a period of time. From 9:00 until 15:00 the water temperature increased due to the gains of heat from the increase in solar radiation; at that point in time the peak temperatures reached 73.1 and 69.7°C, from the numerical and experimental results, respectively.…”