Transport Refrigeration Unit with Vented Cryogenic Cooling

Abstract

A Transport Refrigeration Unit (TRU) includes one or more evaporators inside the TRU each containing two manifold tubes located at opposite ends of the evaporator and a multiplicity of cooling tubes traversing between the manifold tubes; one or more super-insulated vacuum tanks located in front of, beneath or inside the TRU, filled with liquid nitrogen, carbon dioxide or a cryogenic coolant connected to the one or more evaporators using vacuum-insulated pipes; a solenoid or pneumatic valve located upstream or downstream of the evaporator to meter a flow of nitrogen through the evaporator; a temperature controlling circuit that operates the solenoid or pneumatic valve; a flow restricting device that limits the flow of the cryogenic coolant through the evaporator; a vent pipe to vent the spent coolant outside the TRU; and a multiplicity of fans located adjacent to and above the evaporators that distribute the cooled air uniformly throughout the TRU.

What is claimed is: 
     
         1 . A Transport Refrigeration Unit (TRU), comprising:
 one or more evaporators inside the TRU each containing two manifold tubes located at opposite ends of the evaporator and a multiplicity of cooling tubes traversing between the manifold tubes;
 one or more super-insulated vacuum tanks located in front of, beneath or inside the TRU, filled with liquid nitrogen, carbon dioxide or a cryogenic coolant connected to the one or more evaporators using vacuum-insulated pipes; 
 a solenoid or pneumatic valve located upstream or downstream of the evaporator to meter a flow of nitrogen through the evaporator; 
 a temperature controlling circuit that operates the solenoid or pneumatic valve; 
 a flow restricting device that limits the flow of the cryogenic coolant through the evaporator; 
 a vent pipe to vent the spent coolant outside the TRU; and 
 a multiplicity of fans located adjacent to and above the evaporators that distribute the cooled air uniformly throughout the TRU. 
   
     
     
         2 . The device of  claim 1 , comprising a heater located in an air flow path to raise the TRU temperature above the ambient temperature. 
     
     
         3 . The device of  claim 2 , wherein the heater is powered by electricity, propane, liquefied natural gas (LNG), compressed natural gas (CNG), liquefied petroleum gas (LPG), or hydrogen. 
     
     
         4 . The device of  claim 1 , comprising a valve to divert a portion of the nitrogen from the vent pipe to injectors inside the TRU. 
     
     
         5 . The device of  claim 1 , wherein a multiplicity of insulated dividers separate the TRU into multiple compartments, each maintained at a different temperature. 
     
     
         6 . The device of  claim 5 , wherein the temperature of each of the multiple compartments is cooled by a separate evaporator and fan system and controlled by one or more sensors and solenoid valves within each compartment. 
     
     
         7 . The device of  claim 5 , comprising a vent coolant stored in a first compartment, and wherein the vent coolant from the first compartment supplies energy to a multiplicity of compartments. 
     
     
         8 . The device of  claim 7 , wherein two separate valves in each compartment change the source from a main compartment vent to a tank source. 
     
     
         9 . The device of  claim 5 , wherein the insulated dividers retract to a ceiling of the TRU. 
     
     
         10 . The device of  claim 1 , wherein the TRU is insulated with Vacuum Insulated Panels on a plurality of sides. 
     
     
         11 . The device of  claim 1 , comprising a bolt mounting frame coupled to the TRU with a matching bolt layout as a bolt layout for standard semi-trailer tractor TRUs. 
     
     
         12 . The device of  claim 1  wherein the fan and control system are powered by one or more of the following:
 a. Solar panels attached to the outside top of the TRU, 
 b. Nitrogen vent gas turbine generator, 
 c. Stirling engine, 
 d. Fuel cell, 
 e. Deep charge batteries. 
 
     
     
         13 . The device of  claim 1  comprising a multiplicity of cryogenic supply and vent lines with quick disconnect fittings. 
     
     
         14 . The device of  claim 1  comprising a multiplicity of cryogenic supply and vent lines that support sub-cryogenic freezing units within the TRU. 
     
     
         15 . A method for transporting an object with a Transport Refrigeration Unit (TRU), comprising:
 providing one or more evaporators inside the TRU each containing two manifold tubes located at opposite ends of the evaporator and a multiplicity of cooling tubes traversing between the manifold tubes;   providing one or more super-insulated vacuum tanks located in front of, beneath or inside the TRU, filled with liquid nitrogen, carbon dioxide or a cryogenic coolant connected to the one or more evaporators using vacuum-insulated pipes;   metering a flow of nitrogen through the evaporator with a solenoid or pneumatic valve located upstream or downstream of the evaporator;   controlling the temperature with a circuit that operates the solenoid or pneumatic valve;   flow restricting a flow of the cryogenic coolant through the evaporator;   venting the spent coolant outside the TRU; and   distributing cooled air uniformly throughout the TRU with a multiplicity of fans located adjacent to and above the evaporators.   
     
     
         16 . The method of  claim 15 , comprising a heater located in an air flow path to raise the TRU temperature above the ambient temperature. 
     
     
         17 . The method of  claim 16 , comprising powering the heater by electricity, propane, liquefied natural gas (LNG), compressed natural gas (CNG), liquefied petroleum gas (LPG), or hydrogen. 
     
     
         18 . The method of  claim 15 , comprising diverting a portion of the nitrogen from the vent pipe to injectors inside the TRU. 
     
     
         19 . The method of  claim 15 , comprising separating the TRU with a multiplicity of insulated dividers into multiple compartments, each maintained at a different temperature. 
     
     
         20 . The device of  claim 15 , comprising matching bolt layout frame to a bolt layout frame for standard semi-trailer tractor TRUs.