CRYOGENIC COOLING METHOD AND INSTALLATON USING LIQUID CO2 AND EMPLOYING TOW EXCHANGERS IN SERIES

摘要

A method and installation using liquid CO2 as a cryogenic fluid for transferring cold energy to products, wherein liquid CO2 is sent into a heat exchanger system including first and second heat exchangers connected in series. The liquid CO2 is supplied to the first heat exchanger where it evaporates. Gaseous CO2 from the first exchanger is supplied to the second heat exchanger. The atmosphere surrounding the products is blown across the heat exchangers to provide a cooled atmosphere with which to cool the products. The latent heat of vaporization of the liquid CO2 in the first heat exchanger and the sensible heat of the gaseous CO2 in the second heat exchanger satisfies the cooling requirement of the products. The first exchanger is kept at a pressure higher than the triple point pressure for CO2, whereas the second exchanger is held at atmospheric pressure or at a pressure between the triple point of the fluid and atmospheric pressure.