A magnetocaloric air-conditioning system prototype

Abstract

This paper discusses the design procedure and first results of a large-scale magnetic air-conditioning system prototype demonstrated in a relevant environment compatible with the Technology Readiness Level (TRL) 6. The prototype, which contains all components of a functional cooling system, was experimentally evaluated in an especially developed calibrated calorimeter designed according to international technical standards for testing split-type air-conditioning units. The proposed experimental analysis is one of the first to quantify the impact of external losses associated with the heat exchangers on the cooling system performance. For outdoor and indoor temperatures fixed at 35 and 27 °C, respectively, the coefficient of performance disregarding thermal, flow and mechanical losses beyond the limits of the active magnetic regenerator was 5.72, corresponding to a second-law efficiency of 20.7%. When these losses and other essential operating variables, such as the heat exchanger fan power and the valve power consumption, are included, one-order-of-magnitude reductions are observed in the performance parameters, indicating that they should not be neglected in realistic assessments of not-in-kind cooling technologies.