Transcritical CO2 heat pump system, Dynamic COP
Liquid–liquid CO2 heat pump systems are a promising technology for commercial building applications, which require simultaneous heating and cooling. This paper presents the investigation of a data center on the Purdue University, West Lafayette campus. The data center located in the Department of Mathematics is the most energy intensive data center on campus. The cooling load of the data center is approximately 750 kW/hour. The heating season in West Lafayette is 7 to 8 months and the heating load of the buildings is very high during the coldest months. The heating load of the Mathematics building can go to as high as 600 kW/hour during the coldest days of the year. To suffice this simultaneous cooling and heating demand, a liquid-liquid CO2 heat pump is proposed. Presently, the cooling load of the data center is met by eight electrically driven and four steam-driven chillers and the heating load is satisfied by two coal fired and two natural gas boilers. Simulations are performed to compare the proposed CO2 heat pump system with the present system. The assessment shows noteworthy fuel savings and reduction in the CO2 emissions with the system working with a coefficient of performance (COP) of 6.19. If the CO2 heat pump system is installed, 574.92m3/day of natural gas and 751.68 kg/day of coal could be saved on a cold day. The system has the potential to reduce CO2 emissions by 2980.76 kg/day.