I have a project with an air-source heat pump that can either do heating, cooling or simultaneous heating and cooling (4 pipes).

When calculating Rc, if only the cooling capacity is taken into account, this type of equipament will be unfairly penalized. This can easily be demonstrated if compared with a situation where dedicated air-source heat pumps are installed for heating and cooling only (2 pipes), because in this situation it is obvious that the heating capacity must be considered in order to calculate Rc.

Our suggestion is to calculate Rc by dividing the total refrigerant charge by the sum of cooling capacity and corrected heating capacity (evaporator themal capacity when the units is operating in heating mode).

Do you agree with this approach?

Thanks!