how to make CO2 heat pump a better efficiency than normal one

Residential CO2 heat pump systems for both space heating and hot water heating can achieve a similar or even better seasonal performance factor (SPF) compared to the most energy efficient brine-to-water heat pumps, under certain conditions:

- The CO2 heat pump must be able to meet the entire hot water heating demand, with at least 25 to 30% of the total annual heat output being used for hot water production.

- The CO2 heat pump should be used in combined heating mode when there is a need for both space heating and hot water heating at the same time.

- The return temperature in the hydronic space heating system should be around 30ºC or lower.

- The city water temperature should be approximately 10ºC or lower.

- The thermodynamic losses in the hot water storage tank should be minimal, with very little mixing losses and minimal heat transfer between hot and cold water during use.