Use of CO2 in heat pump systems – practical experience with transcritical systems
The use of CO2 as refrigerant in heat pump and refrigeration systems has increased over the past few years in Denmark, especially in the Danish commercial refrigeration market (e.g. in supermarkets). The Danish environmental authorities have implemented a plan for phasing out HFC refrigerants, and the plan has initiated a lot of activities within the fi eld of alternative refrigerants. An essential part of the work has focused on the use of transcritical CO2 in heat pump systems. This presentation concentrates on four projects concerning the use of CO2 as refrigerant in small, mediumsized and large heat pump systems: • CO2 used in domestic hot water heat pumps • CO2 used in heat pumps for commercial applications • CO2 used in HVAC systems (air conditioning and heat pump systems) • CO2 used in large heat pump systems for district heating. It also presents project results obtained through a combination of traditional R&D projects and fi eld test measurements. Finally, the discussion considers the future of CO2in refrigeration and heat pump systems