Cooling storage container in phases

Abstract

A storage container in a current temperature is cooled to a target temperature in two phases comprising a first phase of convective heat transfer from the storage container to dry ice, and a second phase of flowing sublimed dry ice to the storage container. Deviation of the current temperature from the target temperature is measured. The first phase is applied, when the deviation of the current temperature inside the storage container is higher than a threshold value for the deviation. The second phase is applied, when the deviation of current temperature inside the storage container is less than a threshold value.

1 . A method comprising:
 cooling a storage container at a current temperature to a target temperature in two phases comprising:
 a first phase of convective heat transfer from the storage container to dry ice, and 
 a second phase of flowing sublimed dry ice to the storage container; 
   measuring a deviation of the current temperature from the target temperature;   applying the first phase, when the deviation of the current temperature inside the storage container is higher than a first threshold value for the deviation; and   applying the second phase, when the deviation of current temperature inside the storage container is less than a second threshold value.   
     
     
         2 . The method according to  claim 1 , wherein the first threshold value and the second threshold value are the same. 
     
     
         3 . The method according to  claim 1 , wherein when the current cooling phase is the phase of flowing sublimed dry ice to the storage container, the threshold value for evaluating the deviation is high and when the current cooling phase is the phase of convective heat transfer, the threshold for evaluating the deviation is low. 
     
     
         4 . The method according to  claim 1 , wherein the cooling phases are cut-off when the current temperature is lower than the target temperature and the storage container is heated by a free air flow from outside the storage container. 
     
     
         5 . The method according to  claim 4 , wherein the heating of the storage container is stopped, when the current temperature is at the target temperature or within a temperature range from the target temperature. 
     
     
         6 . The method according to  claim 1 , wherein the sublimed dry ice consumed in the cooling phases is conducted out of the storage container and captured in CaO 2 . 
     
     
         7 . A non-transitory computer readable medium comprising executable code that when executed causes a method, the method comprising:
 cooling a storage container at a current temperature to a target temperature in two phases comprising:
 a first phase of convective heat transfer from the storage container to dry ice, and 
 a second phase of flowing sublimed dry ice to the storage container, 
   measuring a deviation of the current temperature from the target temperature;   applying the first phase, when the deviation of the current temperature inside the storage container is higher than a first threshold value for the deviation, and   applying the second phase, when the deviation of current temperature inside the storage container is less than a second threshold value.   
     
     
         8 . An apparatus comprising
 at least one sealed container for dry ice, said at least one sealed container for dry ice being enclosed within another sealed container, wherein the at least one sealed container for dry ice is operatively connected to a storage container for cooling the storage container to a target temperature or to a target temperature range by sublimed dry ice from the at least one sealed container for dry ice,   at least one convection element for convective heat transfer from the storage container to dry ice within the sealed container, wherein said convection element is arranged between the dry ice in the sealed container and the storage container,   a fluid flow control element for controlling flow of sublimed dry ice into the storage container,   at least one sensor being arranged for measuring temperature within the storage container,   a controller connected to the fluid flow control element, and   at least one sensor and the convection element to cause a method, the method comprising:
 cooling a storage container at a current temperature to a target temperature in two phases comprising: 
 a first phase of convective heat transfer from the storage container to dry ice, and 
 a second phase of flowing sublimed dry ice to the storage container, 
 measuring a deviation of the current temperature from the target temperature; 
 applying the first phase, when the deviation of the current temperature inside the storage container is higher than a first threshold value for the deviation, and 
 applying the second phase when the deviation of current temperature inside the storage container is less than a second threshold value. 
   
     
     
         9 . The apparatus according to  claim 8 , wherein said another sealed container has a relief valve that is caused to relieve sublimed dry ice from said another sealed container and out of the apparatus and a CaO2 container is connected to the relief valve for capturing sublimed dry ice consumed in the cooling phases. 
     
     
         10 . The apparatus according to  claim 8 , further comprising a controllable vent for heating the storage container by free air flow from outside the storage container. 
     
     
         11 . The apparatus according to  claim 8 , wherein the at least one sealed container for dry ice is operatively connected to said another sealed container for conducting sublimed dry ice from the at least one sealed container for dry ice to said another sealed container, when the target temperature of the storage container is met. 
     
     
         12 . The apparatus according to  claim 8 , wherein the convection element is arranged in a wall in the sealed container for dry ice and the storage container has a receptacle for receiving the wall for transferring heat to the dry ice by the convection element in the wall positioned in the receptacle. 
     
     
         13 . The method according to  claim 1 , wherein the second threshold value is higher than the first threshold value.