Design of a cooling system for storage of agricultural products with emphasis on Irish potatoes

Abstract

This project focuses on the design of a cooling system for storage of agricultural products. It compares the efficiency of a vapour compression cycle powered by electricity from a binary geothermal power plant, and an absorption refrigeration unit which uses a geothermal heat source to drive the absorption cycle in a chilling process, both in a 25°C environment with a compartment temperature of 5°C. These two cycles are to provide the same cooling to the cold storage with a heat load equivalent to 140 kW. The parameters that were mainly monitored for comparison are COP, the power required to run the cycles, and the required mass flow of a geothermal fluid. After mathematical and thermodynamic analysis of the cycles, it was found that the overall efficiency of a binary plant coupled to the compression refrigeration is a bit low, or 0.432, as it must include both the thermal efficiency of the plant and the COP of the compression cycle, and that of the absorption refrigeration cycle is 0.471, but can go as high as 0.6 when a heat exchanger is used.