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Participating countries

Canada, Denmark, Japan, the Netherlands, Norway, Switzerland, United Kingdom, USA.

Compression Systems with Natural Working Fluids

Most of the substances being considered to replace chlorofluorocarbons (CFCs) and HCFCs as working fluids in heat pumping (heat pump, air conditioning and refrigeration) systems are new synthetic compounds, foreign to nature. Extensive use of such man-made compounds may yield unforeseen environmental effects, as has already been experienced with CFCs and HCFCs. By applying naturally occurring and ecologically safe substances as working fluids, uncertainties and potential negative environmental effects are eliminated.

To further develop the technology and expand the knowledge on natural working fluids in compression heat pumping systems, this project was set up. Fluids covered included: ammonia, hydrocarbons, carbon dioxide, water and air. The project – Annex 22 of the IEA Heat Pump Programme – was entitled: Compression Systems with Natural Working Fluids.


The objectives of the project were:

  • To present up to date information
  • To carry out research, development and demonstration activities
  • To establish acknowledged guidelines for component and system design