Research of CO2 high temperature heat pump for industrial steam generation with data center heat source

Abstract

The solution of integrating large-scale high-temperature heat pump (HTHP) with data center not only reduces carbon emissions but also enhances energy efficiency, aligning with dual-carbon goals. However, pressure ratios and environmentally friendly refrigerants limit the conventional HTHPs. Therefore, this paper proposes an improved transcritical CO₂ HTHP steam system (CO₂-NC) with dual-pressure gas coolers and expander. Detailed thermodynamic analysis, exergy analysis, and economic analysis are conducted to evaluate the cycle performance. Compared to the conventional CO₂ cycle, the COP of CO₂-NC is improved by 32.7 %, and the pressure ratio is reduced by 13.22 %, with a 110 °C saturated steam supply. With the superior thermal matching performance of dual-pressure gas coolers, the irreversible loss of gas coolers in CO₂-NC is diminished by 75.89 %. The total pressure ratio of CO₂-NC is less than 1/4 of that in the conventional cycles with HFC/HFO refrigerants, providing an advantage in large-scale HTHPs with centrifugal compressors. Exergy analysis highlights that the expander in the CO₂-NC decreases irreversible losses in the expansion process by 81.27 %. CO₂-NC with the least variation in COP and pressure ratio shows excellent adaptability to data center heat sources, and CO₂-NC exhibits the least variation with changes in saturated steam temperature. Furthermore, the optimum compressor discharge pressure for CO₂ HTHPs is analyzed. Economic analysis highlights the advantages of CO₂-NC in operation and refrigerant costs with the constraints of high initial capital costs. This study emphasizes the potential of combining transcritical CO₂ HTHP to fulfill data center cooling and industrial heating needs.