Analysis and optimization on energy and exergy bases of a flat plate solar collector with integrated PCM compared with a traditional device

In this paper, two flat plate solar collectors were evaluated under the same operating conditions from energy and exergy perspectives. one of these prototypes was modified with an integrated energy storage system with PCM under the absorber plate, and the other one is a traditional collector used as a baseline to conduct a comparative analysis. A thermal model based on the first and second laws of thermodynamic was used to evaluate the energy and exergy thermal performance of both collectors. The model was validated with experimental measurements for three study cases: high, medium, and low solar radiation. Results show that the PCM collector presented higher outlet water temperature in nocturnal times, even to provide useful heat during the whole night, with similar energy and exergy efficiencies as those obtained by the traditional collector. In addition, the model was used to find optimum design parameters of the collector and desirable thermal properties of the PCM to maximize the performance of the overall system. The parameters obtained on the optimization process were evaluated for the three study cases, and significant improvements on the estimated thermal energy harnessing and potential useful heat were obtained.