Method for Dispensing a Gas

Abstract

A method for dispensing gas within a target temperature range wherein the gas exchanges heat with multiple thermal capacitors to cool the gas.

We claim: 
     
         1 . A method for dispensing gas, the method comprising:
 dispensing a gas from a gas source at an initial temperature into a receiving vessel at a dispensing temperature, the dispensing temperate being within a first target temperature range and being lower than the initial temperature;   cooling the gas from the initial temperature to the dispensing temperature during the dispensing step via heat exchange with a plurality of thermal capacitors arranged in series;   circulating a refrigerant to each of the plurality of thermal capacitors using a refrigeration unit; and   performing the circulating step for each of the plurality of thermal capacitors as a function of a measured temperature of each of the plurality of thermal capacitors and independently of whether the cooling step is being performed.   
     
     
         2 . The method of  claim 1 , further comprising:
 repeating the dispensing step without performing the circulating step, wherein the dispensing step comprises dispensing at least  3  kg of the gas.   
     
     
         3 . The method of  claim 1 , further comprising:
 providing each of the plurality of thermal capacitors with a sufficient thermal mass to enable a dispensing step in which at least  5  kg of gas is dispensed without performing the circulating step.   
     
     
         4 . The method of  claim 1 , further comprising:
 performing at least a portion of the circulating step when the dispensing step is not being performed.   
     
     
         5 . The method of  claim 1 , wherein the cooling step comprises cooling the gas via heat exchange with at least two of the plurality of thermal capacitors and heating the gas via heat exchange with a last of the plurality of thermal capacitors. 
     
     
         6 . A method for dispensing a gas, the method comprising:
 withdrawing a first quantity of the gas from a gas source, the first quantity of gas having an initial temperature;   cooling the first quantity of gas via heat exchange with a first thermal capacitor wherein the first thermal capacitor has a temperature lower than the minimum temperature of a first target temperature range when the first quantity of gas is initially cooled by the first thermal capacitor;   cooling the first quantity of gas via heat exchange with a second thermal capacitor wherein the second thermal capacitor has a temperature lower than the minimum temperature of the first target temperature range when the first quantity of gas is initially cooled by the second thermal capacitor, wherein the first quantity of gas is cooled via heat exchange with the second thermal capacitor after being cooled via heat exchange with the first thermal capacitor;   heating the first quantity of gas via heat exchange with a third thermal capacitor wherein the third thermal capacitor has a temperature within the first target temperature range, wherein the first quantity of gas exchanges heat with the third thermal capacitor after being cooled via heat exchange with the second thermal capacitor; and   introducing the first quantity of gas from the third thermal capacitor into a first receiving vessel, the first quantity of gas thereby having a dispensing temperature within the first target temperature range, wherein the dispensing temperature is less than the initial temperature.   
     
     
         7 . The method of  claim 6  further comprising:
 withdrawing a second quantity of the gas from the gas source; 
 cooling the second quantity of gas via heat exchange with the first thermal capacitor; 
 cooling the second quantity of gas via heat exchange with the second thermal capacitor, wherein the second quantity of gas is cooled via heat exchange with the second thermal capacitor after being cooled via heat exchange with the first thermal capacitor; 
 heating or cooling the second quantity of gas via heat exchange with the third thermal capacitor wherein the third thermal capacitor has a temperature within the first target temperature range, wherein the second quantity of gas exchanges heat with the third thermal capacitor after being cooled via heat exchange with the second thermal capacitor; and 
 introducing the second quantity of gas from the third thermal capacitor into a second receiving vessel, the second quantity of gas thereby having a dispensing temperature within the first target temperature range. 
 
     
     
         8 . The method of  claim 6  further comprising:
 cooling the first thermal capacitor, the second thermal capacitor, and the third thermal capacitor via heat exchange with a refrigerant, wherein the refrigerant is cycled in a refrigeration cycle. 
 
     
     
         9 . The method of  claim 8  wherein the flow rate of the refrigerant to each of the first thermal capacitor, the second thermal capacitor, and the third thermal capacitor is independently controlled. 
     
     
         10 . The method of  claim 6  further comprising:
 cooling the first thermal capacitor and the second thermal capacitor via heat exchange with a refrigerant, wherein the refrigerant is cycled in a refrigeration cycle; and 
 cooling the third thermal capacitor via heat exchange with a second refrigerant, wherein the second refrigerant is cycled in a second refrigeration cycle. 
 
     
     
         11 . The method of  claim 6  further comprising:
 withdrawing a third quantity of the gas from the gas source; 
 cooling the third quantity of gas via heat exchange with the first thermal capacitor; 
 cooling the third quantity of gas via heat exchange with the second thermal capacitor, wherein the third quantity of gas is cooled via heat exchange with the second thermal capacitor after being cooled via heat exchange with the first thermal capacitor; 
 heating or cooling the third quantity of gas via heat exchange with a fourth thermal capacitor wherein the fourth thermal capacitor has a temperature within a second target temperature range, wherein the second target temperature range is different than the first target temperature range, and wherein the third quantity of gas exchanges heat with the fourth thermal capacitor after being cooled via heat exchange with the second thermal capacitor; and 
 introducing the third quantity of gas from the fourth thermal capacitor into a third receiving vessel, the third quantity of gas thereby having a dispensing temperature within the second target temperature range. 
 
     
     
         12 . The method of  claim 11  further comprising:
 measuring an ambient temperature representative of conditions surrounding a fourth receiving vessel; 
 withdrawing a fourth quantity of the gas from the gas source; 
 cooling the fourth quantity of gas via heat exchange with the first thermal capacitor; 
 cooling the fourth quantity of gas via heat exchange with the second thermal capacitor, wherein the fourth quantity of gas is cooled via heat exchange with the second thermal capacitor after being cooled via heat exchange with the first thermal capacitor; 
 heating or cooling the fourth quantity of gas via heat exchange with one of the third thermal capacitor and the fourth thermal capacitor, the third thermal capacitor having its temperature within the first temperature range, the fourth thermal capacitor having its temperature within the second temperature range, the selection of heating or cooling the fourth quantity of gas via heat exchange with the third thermal capacitor or the fourth thermal capacitor dependent upon the measured ambient temperature surrounding the fourth receiving vessel; and 
 introducing the fourth quantity of gas from the third thermal capacitor or from the fourth thermal capacitor into the fourth receiving vessel, the fourth quantity of gas thereby having a dispensing temperature within the first target temperature range when the fourth quantity of gas exchanges heat with the third thermal capacitor or having a dispensing temperature within the second target temperature range when the fourth quantity of gas exchanges heat with the fourth thermal capacitor. 
 
     
     
         13 . The method of  claim 6  wherein at least one of the first thermal capacitor, the second thermal capacitor, and the third thermal capacitor comprises a metal. 
     
     
         14 . The method of  claim 13  wherein the metal is aluminum. 
     
     
         15 . The method of  claim 6  wherein at least one of the first thermal capacitor, the second thermal capacitor, and the third thermal capacitor comprises a liquid. 
     
     
         16 . The method of  claim 15  wherein the liquid is a liquid hydrocarbon. 
     
     
         17 . The method of  claim 16  wherein the liquid hydrocarbon is a C10 to C13 iso-alkane. 
     
     
         18 . The method of  claim 6  further comprising:
 withdrawing a fifth quantity of the gas from the gas source; and 
 introducing the fifth quantity of gas from the gas source into a fifth receiving vessel without cooling the fifth quantity of gas between withdrawing the fifth quantity of gas from the gas source and introducing the fifth quantity of gas into the fifth receiving vessel. 
 
     
     
         19 . The method of  claim 6  further comprising:
 measuring an ambient temperature representative of conditions surrounding the first receiving vessel prior to withdrawing the first quantity of gas from the gas source; and 
 setting the first target temperature range dependent upon the measured ambient temperature prior to withdrawing the first quantity of gas from the gas source.