| abstract |
A transcritical vapour compression refrigeration apparatus which comprises a compressor ( 1 ), a gas cooler ( 3 ), an economiser ( 7 ), an evaporator ( 9 ) and a refrigerant; the refrigerant being compressed in the compressor, heat being rejected from the compressed refrigerant at supercritical pressure in the gas cooler, the cooled compressed refrigerant being then expanded in a first stage to first temperature and pressure conditions in the economiser and then expanded in a second stage to second temperature and pressure conditions; a stream of refrigerant from the economiser at said first temperature and pressure conditions then being compressed in a first stream in the compressor; refrigerant at said second temperature and pressure conditions absorbing heat in the evaporator and then being compressed in a separate second stream in the compressor; said first and second compressed streams then being combined before passing to the gas cooler; or the first and second compressed streams passing through separate gas coolers before being combined. Preferably, the ratio of swept volume of the second stream to the first stream is in the ration of 1.1-11 to one. A preferred refrigerant is carbon dioxide. |