Energy payback time, exergoeconomic and enviroeconomic analyses of using thermal energy storage system with a solar desalination system: An experimental study

Abstract

In this study, the performance of solar still incorporated with thermal energy storage (TES) unit of phase change material (PCM) is evaluated based on energy and exergy methodologies. Energy payback time for solar still with and without PCM is quantified and compared. Furthermore, the performance of both configurations is also evaluated from exergoeconomic and exergoenvironmental points of view. Experiments for solar still with and without PCM are conducted in summer and winter seasons subjected to the weather conditions of Alexandria, Egypt. The findings showed that the addition of a PCM storage unit to solar still system increased the annual energy and exergy savings by 10% and 3%, respectively. The results indicated that the incorporation of PCM in solar still was found ineffective compared to traditional still based on energy payback time. Based on the exergy approach, the integration of PCM in the solar still system is not effective where the conventional still (without PCM) achieved more than 400% more CO2 mitigations compared to PCM-based solar still system. Also, the exergoeconomic and exergoenvironmental parameters of the modified system were very poor related to those of traditional still. Therefore, for PCM-based solar stills systems to become competitive from global energy and environmental approaches, attempts should be performed by industrialists and engineers to find storage materials with low embodied energy and with low cost in conjunction with its evaluation from energy and exergy outputs to get a complete picture about the effectiveness of the system. In this case, the potential of thermal energy storage techniques for low-temperature solar-powered desalination systems will be thermodynamically, economically, and environmentally effective.