Özet:

: In this work we analyze numerically different design configurations to be used in a R1234yf DMS cycle coupled with a water source, transcritical CO 2 heat pump for heating applications in the building sector. Specifically, we study the temperature range proposed by a European standard for heating with inlet/outlet water temperatures of: 30 °C/35 °C, 40 °C/45 °C, 47 °C/55 °C and 55 °C/65 °C. Moreover, 25 °C/30 °C is also analyzed which is the range expected for indoor swimming pool water pool heating applications. A water inlet temperature of 10 °C at the evaporator was considered in all of the cases. Results show that depending on the coupling strategy between the DMS cycle and the CO 2 heat pump, optimal COP values obtained can vary up to 30% whereas the optimal operating pressure of the CO 2 cycle can vary up to 8%. A configuration based on splitting the water flow to be heated into the DMS condenser and the gas cooler in a system with IHX was the best option for all the temperature ranges studied. The improvement in the maximum COP values obtained with this configuration ranges between 5% (for swimming pool applications) and 25% (for space heating with 40 °C/45 °C) when compared with the base cycle depending on the water temperature range considered. When this configuration is not considered, the basic transcritical CO 2 with IHX and without DMS was found the best option.

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