EcoPack 3

Synthetic refrigerants with high GWP are being substituted in refrigeration and heat pump systems for highly flammable hydrocarbons. To maintain safety with these fluids it is essential that the charge of refrigerant is low. EcoPack3 is the third in a series of projects where we develop heat pump components and systems with low charge. We have demonstrated the design of a heat pump with 12 kW capacity using only 120g of isobutane as refrigerant. This has been achieved by using very compact heat exchangers and the type of compressors used in electric cars.

Background

A hundred years ago CFCs (“Freons”) were introduced as “safety refrigerants”, being non-toxic and non-flammable. It took about 50 years until their effect on the ozone layer was realized. Instead, HFC-refrigerants became the standard, but after another 10 years the high effect on global warming (GWP) of these fluids was highlighted, and they are now being phased out by international agreements. About 15 years ago, the industry introduced HFO-refrigerants, with no effect on the ozone layer and very low GWP. However, these fluids, like CFCs and HFCs belong to the group of PFAS-substances which need to be phased out due to their effect on human health as well as other living organisms. Already thirty years ago, researchers proposed the use of natural fluids as refrigerants as such substances are already present in the environment and no unexpected effects are foreseen when used as refrigerants.

KTHs Division of Applied thermodynamics and refrigeration was one of the first university groups studying hydrocarbons as refrigerants. In particular, we realized the need for decreasing the refrigerant charge if hydrocarbons should be accepted by the industry and the public. Already in 2002, we arranged a conference called Zero Leakage, Minimum Charge! Now, many universities and institutes in Europe and worldwide are studying charge minimization and safety with flammable refrigerants, and products with hydrocarbons are taking on an increasing share of the market in Europe. Other regions are expected to follow.

This project will continue the work towards the use of natural, non-synthetic fluids as refrigerants in refrigeration systems and heat pumps.