The maximum discharge pressure for highest COP in heat
recovery operation is dependent on the CO2 exit temperature
from the de-superheater; in this case 88 bar for 35 C exit from
the de-superheater. It follows the same correlation for the
optimum discharge pressure for maximum COP in a CO2
refrigeration system.
Following the suggested control strategy in this study, the
analyzed CO2 system produces heating COP1HR higher than
a typical heat pump for almost all the calculated temperature
range.