Performance mapping of the thermoelectric subcooler devoted to domestic heat pump applications

sustainable development goals because of their low global warming potential index. For this reason, novel methods must be developed to integrate natural refrigerants such as hydrocarbons and meet the requirements of the F-Gas Regulation. The thermoelectric subcooling method is one of the state-of-the-art methods for improving the coefficient of performance (COP) of vapour compression systems. Thus, the main aim of this paper is to investigate the proposed thermoelectric subcooler (TESC) design performance and create a map to find key takeaways for further studies. Research has been carried out on two different TESC designs (TESCconv, TESC3D), zig-zag and pin-shaped, made of two different materials, copper and AlSi10Mg, with two different manufacturing methods, conventional drilling and welding and 3D-printing, respectively. The TESCs were integrated downstream of the condenser in an 8.0 kW propane (R290) heat pump and experiments were performed for operating conditions where the propane temperature ranged from 40 ◦C to 50 ◦C, the auxiliary water stream temperature ranged from 30 ◦C to 60 ◦C and the voltage ranged from 1.0 to 8.0 V DC. The results showed that TESC3D is superior to TESCconv in terms of the cooling and heating capacity and that the coefficient of performance is between 1% and 17%. TESC systems can be useful for small-scale applications and can provide up to 270 W of additional cooling capacity with a cooling coefficient of performance of 1.22 and up to 490 W of additional heating with a heating coefficient of performance of 2.22. Furthermore, the best heating and cooling coefficient of performance was obtained in the TESC3D design at 1.0 V DC with a 115 W cooling capacity and 123 W heating capacity when the R290 temperature was 50 ◦C and the auxiliary water flow temperature was 40 ◦C.