On the optimisation of a direct current (dc) hot-wall refrigerator

Abstract

This study presents an experimental investigation conducted on a refrigerator powered by direct current and composed of a 166L cabinet, a condenser embedded in the external wall of the compartment (hot-wall), an internal static evaporator, a hermetic variable speed compressor. The refrigerant fluid used is the R290a, a natural fluid. By placing the refrigerator in a temperature-controlled environment, four external temperatures have experimented: 22, 25, 29 and 32 °C. Three different temperature setpoints have been set for each temperature: -5, -10, -20 °C. In this way, 12 test conditions were defined, and each of them was repeated by imposing four different compressor rotation speeds: 2000, 2500, 3000, 3500 rpm. The set of tests allowed to identify for each operating condition the optimal number of operating revolutions aimed at minimising the energy consumption of the analysed device.