Stored cryogenic refrigeration

Refrigeration apparatus for cooling material using stored cryogenic refrigeration, which apparatus comprises

• thermally insulated chamber means,
• means for supplying said chamber means with cryogen,
• means associated with said chamber means for creating a reservoir of solid and liquid cryogen in said chamber means at or near the triple point where solid, liquid and vapor exist in equilibrium, and
• means for separating liquid cryogen from said reservoir of solid cryogen, removing said liquid cryogen from said chamber, circulating said removed liquid cryogen exterior of said chamber to heat-exchange means, vaporizing said circulating liquid cryogen by absorbing heat from material being cooled and then removing said absorbed heat from said cryogen vapor by melting solid cryogen in said reservoir in said chamber means.

Refrigeration apparatus using stored cryogenic refrigeration, which apparatus comprises

• thermally insulated chamber means,
• means for supplying said chamber means with cryogen,
• means associated with said chamber means for creating a reservoir of solid cryogen in said chamber means at or near the triple point where solid, liquid and vapor exist in equilibrium,
• a mechanical refrigeration unit employing a fluid refrigerant which is normally supplied to a refrigeration load in liquid form at a first temperature and evaporated,
• means for employing the stored refrigeration in said reservoir of solid cryogen to condense the refrigerant following evaporation at said refrigeration load and to cool said condensed refrigerant to a second temperature which is lower than said first temperature, and
• means for returning said condensed refrigerant to said refrigeration load at a temperature below said first temperature for another pass therethrough.

A refrigeration method for supplying refrigeration over an extended period to a refrigeration load varying in size, which method comprises

• employing a mechanical refrigeration unit to cool a refrigeration load by circulating a liquid refrigerant to said load where said refrigerant evaporates, recovering and condensing said evaporated refrigerant,
• establishing a reservoir of solid cryogen in equilibrium with liquid cryogen and cryogen vapor at or near the triple point within thermally insulated chamber means,
• diverting excess liquid refrigerant from said mechanical refrigeration unit to a first condenser,
• withdrawing cryogen vapor from said chamber means, compressing said vapor and supplying said compressed vapor to said first condenser to form liquid cryogen at a pressure above said triple point pressure,
• returning said higher pressure liquid cryogen to said chamber means via expansion means, whereby additional solid cryogen is formed,
• periodically diverting evaporated refrigerant from said mechanical refrigeration unit to a second condenser,
• condensing said diverted refrigerant therein, in a manner which results in melting solid cryogen in said reservoir, and
• returning said condensed diverted refrigerant to said refrigeration load.

A refrigeration method using stored cryogenic refrigeration, which method comprises

• creating a reservoir of solid cryogen in equilibrium with liquid cryogen and cryogen vapor in thermally insulated chamber means at or near the triple point,
• employing a mechanical refrigeration unit to cool a refrigeration load by circulating a liquid refrigerant at a normal first temperature to said load where said refrigerant evaporates,
• periodically diverting evaporated refrigerant from said mechanical refrigeration unit and cooling and condensing said diverted refrigerant to a second temperature near or below said first temperature by employing the stored refrigeration in said reservoir of solid cryogen, and
• returning said condensed liquid refrigerant to said refrigeration load at a temperature near or below said normal first temperature.