Comparación de bombas de calor con ciclo de compresión simple etapa y ciclo de compresión con inyección de vapor para producción de agua caliente sanitaria

Abstract

This research work aimed to compare heat pumps operating with single-stage compression cycles and double-stage compression cycles with steam injection for sanitaryhot water (SHW) production. Firstly, a literature review was carried out on the vapour compression cycle used in heat pumps for DHW, its components, single-stage,and double-stage compression types. To compare the performance of theheat pumps, thermodynamic models based on previous literature were implemented. Using the implemented models, the operation of the twoSHW heat pumps was simulated, considering, on the one hand, various condensation,and evaporation temperatures and, on the other hand, the thermal jump of the secondary fluid with various water outlet temperatures. The following refrigerants were considered in the simulations: R134a, R290, R407C, R32, R152a, R410a, R161 and R1234yf. The comparison of the performance of the heat pumps was carried out in terms of heat capacity, COP,and compressor discharge temperature. The results show that the double-stage heat pump has a coefficient of performance (COP) 10.7% higher, a heat capacity 37% higher and a discharge temperature 1 K lower than the single-stage pump, when the working conditions have a condensing temperature of 60 degrees Celsius and an evaporating temperature of 0 degrees Celsius, with R134a as the refrigerant and a volumetric flow of 14.27 cubic metersper hour in both compressors. Considering the thermal jump of the secondary fluid, the double-stage heat pump, working with R407C refrigerant, has a COP 5.8% higher than with R134a refrigerant with a water outlet temperature of 60 degrees Celsius. Considering the same heat capacity at a nominal operating point, the double-stage heat pump requires a 7.7% smaller downstream compressor size than the single-stage heat pump.