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Most cooling systems in buildings use a refrigerant vapour in a cycle of compression and expansion. In part of the cycle the refrigerant is hot and in another part the refrigerant is cold. When required the hot part of the system can be used for heating and the cold part for cooling. Some of these systems provide as much cooling and heating energy as the energy used to provide it in the first place and are described as having a coefficient of performance (COP) of 1; others consume no more energy yet provide twice as much heating or cooling and therefore have a COP of 2. As the vapour changes from hot to cold in virtually all systems there is a loss of useful energy. The loss is caused by the systems inability to make use of the energy in the expanding vapour; this loss is equal to about 25% of the energy input to the system.

Our turbine technology makes use of the expanding vapour and our compressor has less friction in the compression process. These two substantial improvements and the ability to vary the flow rate at a constant speed and pressure, result in a COP of about 5 over a range of heating and cooling output values.

There is environmental pressure to replace vapour refrigerants with air in automotive air conditioners. This is because in arduous automotive applications some of the vapour refrigerant (generally a fluorocarbon) leaks and escapes into the atmosphere. The COP of an air cycle system is generally less than 1 and the energy must be provided by the vehicle’s engine which itself produces undesirable environmental emissions. If our vapour compression system with a COP of 5 is used, the environmental consideration turns to favour using vapour refrigerants.

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