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Environmental aspects of the CO2 heat pump


The aim of most heat pumps is to reduce the energy consumption from the grid with as little effect on the environment as possible. Along with the added benefits with regards to performance of CO2 in the refrigeration cycle it also possesses environmental benefits.

CO2 or R-744 is classed as a natural refrigerant and all of these are becoming more popular because of the damage done to the ozone and the climate of the earth by the traditional refrigerants like HFCs, CFCs and CHFCs. The use of natural refrigerant will enable to avoid all the potential leakage of the traditional ones during their production and use in the heat pump.

The two main criteria or standard of measurement by which refrigerants are assessed and compared are its Ozone Depletion Potential (ODP) and Global Warming Potential (GWP). The table below highlights some of the environmental comparisons between CO2 and other traditional refrigerants:


Table 1. Environmental impact comparison

It can be noticed that the use of HFC instead of HCFC enable to deal with the ozone depletion problem. However their global warming potential is very important in comparison with natural refrigerants.

It would be also interesting to study the total CO2 emissions associated with the use of the heat pump. In comparison with a simple electric heater, the carbon footprint for a heat pump during the system operation will be divided by the seasonal performance factor of the installation (as seen in the economical aspects page). However, a heat pump is a more complex device which might have a higher carbon footprint for its production. Further study will be required to assess the actual improvement linked to the use of a heat pump instead of an electric heater.


Table 1: Figures taken from


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