Design and experimental characterization of a multi-layout R1233zd(E) high temperature heat pump
A 40 kW high temperature heat pump for thermal upgrade up to 130°C has been developed and experimentally tested as part of the THUNDER Horizon EU project, which focuses on an innovative approach to data centre waste heat reutilisation. Security constraints imposed by data centre operators required the use of an A1 working fluid. R1233zd(E) has been selected for its safety, lack of GWP limitations and low PFAS-related issues. A preliminary numerical model was developed to support the selection of the main components and to provide an initial assessment of the expected performance variations under different system layouts. This approach enabled a more efficient experimental design, helping to identify the most promising configurations for maximizing the heat pump efficiency. The device has been equipped with a highly flexible scroll compressor and two performance-enhancing components, such as an economiser and an internal regenerative heat exchanger. Different layouts and the influence of these two heat exchangers have therefore been experimentally tested, varying the temperature lift at different evaporation levels. Even though the use of a regenerative internal heat exchanger is not mandatory considering the shape of the saturation curve, to avoid wet compression, its use can improve device performance up to 5%. A similar effect is observed when the economizer is included in the circuit, while the combined use of both heat exchangers can increase the COP up to 9.5%