Performance evaluation of solar-powered adsorption cooling system with fixed average chilled water outlet

Abstract

Interest in utilizing solar-driven refrigeration systems for air-conditioning or refrigeration purposes has been growing continuously. Solar air conditioning appears highly attractive to the public since more cooling is needed when the solar intensity is strong and ambient temperature is high. Solar cooling is comprised of many attractive features and one of them is the path to develop a more sustainable energy system. In this research, a solar driven adsorption refrigeration system has been selected as a case study for a further detailed investigation. Adsorption cycle has a distinct advantage over other refrigeration systems in its ability to be driven by the heat on relatively low, near-environment temperature. Both experimental and simulation based investigation of adsorption cooling systems shows that the performance of adsorption chillers depend highly on the adsorbent-refrigerant pairs, the choice of operating conditions, and cycle operation time. Many studies were carried out to that different number of collectors and different cycle operation time influences the performance of the chiller. The purpose of this research is to develop a single stage adsorption refrigeration system which utilizes solar heat source to get a fixed average chilled water outlet temperature during the day time for the climatic condition of Dhaka, Bangladesh. In this study, the chilled water mass flow rate has been changed as necessary to keep the chilled water outlet temperature fixed at 7°C. Silica gel and water have been considered here as a working pair. The climate data of the month of April has been chosen to investigate the optimal collector numbers and cycle time based on the performances. The change of chilled water mass flow rate with respect to time is also observed here. Cyclic average cooling capacity (CACC) and coefficient of performance (COP) has also been numerically investigated with different number of collectors and cycle time. It is seen that 16 solar collectors are needed along with 1100s cycle time to get the maximum cooling capacity of 8.1kW and maximum cycle COP of 0.5. The prosperity of the installation of this choice is also studied here for the several months of the year.