Expendable Refrigerant System
The use of liquid nitrogen and liquid carbon dioxide for cooling vehicles are becoming more popular. Expendable refrigerants are used in cooling wagons and containers for the transportation of perishable goods. Base system uses liquid, non-toxic, low temperature refrigerant. This is the same as steam, and the system but has condensing unit. Low-cost liquid can be used as a refrigerant is then dumped into the atmosphere. This is called chemical or open cycle cooling.
Refrigerant the latent heat of vaporization is a measure of its heat-absorbing ability. Fig. 18-10 illustrates absorbent ability of liquid nitrogen and liquid carbon dioxide. Both are quite high in the latent heat of vaporization. If properly handled, they create little air pollution. The refrigerant is served in the large cylinders.
Two main cooling mechanisms are in common use. One cold plate cooling; other cooling.
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