Design and simulation of a solar thermal cooling system for national medical stores

Abstract

Solar energy is a clean form of energy that is essential for nearly all natural processes. Solar thermal cooling offers multiple advantages compared to conventional electrically powered systems. A study was conducted to design and simulate a solar thermal cooling system for the cold storage facility at the National Medical Stores, to solve the problem of the high electricity cost incurred while running the current cold storage cooling system. The system was designed using assorted calculations and the respective parameters were acquired, it was modeled and simulated, to use flat plate collectors and a LiBr-water absorption chiller. The solar-powered absorption cooling system simulation was carried out using the TRNSYS simulation program, with weather parameters for Kampala, Uganda where the facility is located, and the results indicated that the system is viable and applicable, and can provide the required cooling sufficiently. To ensure continuous system performance and increase reliability, a 119m3 hot water storage tank was included in the system, to ensure that the system can continue running for 48 hours for periods when there is no solar radiation. The system was designed with a capacity of 315kW (89.6 refrigeration tons), a 1,487m2 flat plate solar collector tilted at 100 to the horizontal, and its coefficient of performance (C.O.P) determined as 0.667. The system was successfully designed and simulated and the development is recommended for National Medical Stores in order to control the high costs of electricity that are generated from using grid power. .