The producers of HFCs dismiss the high global warming potential of their products by claiming that in optimized equipment the TEWI of HFCs is lower than that of natural refrigerants. This claim is incorrect. In both domestic and commercial refrigeration the TEWI of HFC-134a, for example, is actually higher than its natural refrigerant alternatives.
A 1994 UNEP Information Paper writes: "Testing to date shows that refrigerators with HC-600a [isobutane] systems are nearly always more efficient than equivalent ones using HFC-134a and often more efficient than those using CFC-12. "* Combining these test results with the nearly zero global warming potential of hydrocarbons indicates that the TEWI rating of hydrocarbon domestic refrigeration technology will be lower than those using HFCs.
Meanwhile, the energy efficiency of hydrocarbon-based domestic Greenfreeze refrigerators is constantly improving . For example, in 1994 Bosch-Siemens reported energy savings of up to 50% with a 360 liter unit. This super efficient refrigerator is completely CFC, HCFC and HFC-free. It has the energy consumption of .10kWh/100 liters-- the equivalent of a 15 Watt light bulb. In 1995, Electrolux Compressors is introducing a new hydrocarbon compressor that is 30% more efficient than existing models.
In supermarket refrigeration Westward Refrigeration of Gloucester conducted TEWI tests for the major UK retailer Sainsbury. Two HFC & HCFC systems were compared with an ammonia based secondary cooling system. The tests concluded that the overall TEWI of the system using ammonia was 5% less than that of a HCFC 22 / HFC-134a system, and 17% lower than the system using HFC-404a.**
These tests convinced Sainsbury to install an ammonia based secondary cooling system in a new superstore in Horsham, Sussex, even though just 18 months earlier the company stated "it is madness to suggest that a modern supermarket might equip with ammonia".***
