Transportation refigeration system

Abstract

A transportation refrigeration unit (TRU) system is provided and includes a damper assembly configured to direct air flows through first or second pathways and an evaporator disposed in the first pathway, a coil element surrounded by phase change material (PCM) and disposed in the second pathway and a routing assembly configured to direct refrigerant through the evaporator or the coil element. With the PCM pre-cooled, the damper and routing assemblies are controllable to respectively direct the air flows through the first pathway and the refrigerant through the evaporator when first conditions are met and to respectively direct the air flows through the second pathway when second conditions are met.

What is claimed is: 
     
         1 . A transportation refrigeration unit (TRU) system, comprising:
 a damper assembly configured to direct air flows through first or second pathways; and   an evaporator disposed in the first pathway, a coil element surrounded by phase change material (PCM) and disposed in the second pathway and a routing assembly configured to direct refrigerant through the evaporator or the coil element,   wherein, with the PCM pre-cooled, the damper and routing assemblies are controllable to respectively direct:
 the air flows through the first pathway and the refrigerant through the evaporator when first conditions are met, and 
 the air flows through the second pathway when second conditions are met. 
   
     
     
         2 . The TRU system according to  claim 1 , wherein:
 the PCM is pre-cooled with grid or battery power,   the first conditions are high-load conditions, and   the second conditions are low-load conditions.   
     
     
         3 . The TRU system according to  claim 1 , wherein:
 the damper assembly comprises first dampers at an outlet of the first pathway, second dampers at an outlet of the second pathway and third dampers between the first and second pathways, and   the routing assembly comprises first and second piping fluidly connecting an expansion valve with the evaporator and the evaporator with a compressor, respectively, first and second valves disposed along the first and second piping, respectively, third and fourth piping fluidly connecting the first piping with the coil element and the coil element with the second piping, respectively, and third and fourth valves disposed along the third and fourth piping, respectively.   
     
     
         4 . The TRU system according to  claim 3 , wherein:
 the first, second and third dampers are closed, the first and second valves are closed and the third and fourth valves are opened while the PCM is pre-cooled,   the first dampers are opened, the second and third dampers are closed, the first and second valves are opened and the third and fourth valves are closed when the first conditions are met, and   the first dampers are closed, the second and third dampers are open and at least the third and fourth valves are closed when the second conditions are met.   
     
     
         5 . The TRU system according to  claim 1 , wherein the coil element comprises:
 the PCM; and   refrigerant tubes extending through the PCM and through which the refrigerant, which is directed through the coil element, flows.   
     
     
         6 . The TRU system according to  claim 1 , wherein the coil element comprises a plurality of coil element slabs between which the air flows, which are directed through the coil element, proceed. 
     
     
         7 . A transportation refrigeration unit (TRU) system, comprising:
 an air supply chamber comprising a damper assembly configured to direct air flows through first or second pathways;   a vapor compression cycle comprising an evaporator disposed in the first pathway, a coil element surrounded by phase change material (PCM) and disposed in the second pathway and a routing assembly configured to direct refrigerant through the evaporator or the coil element; and   a controller configured to pre-cool the PCM and to control the damper and routing assemblies to respectively direct:
 the air flows through the first pathway and the refrigerant through the evaporator when first conditions are met, and 
 the air flows through the second pathway when second conditions are met. 
   
     
     
         8 . The TRU system according to  claim 7 , wherein:
 the controller pre-cools the PCM with grid or battery power,   the first conditions are high-load conditions, and   the second conditions are low-load conditions.   
     
     
         9 . The TRU system according to  claim 7 , wherein the damper assembly comprises:
 first dampers at an outlet of the first pathway;   second dampers at an outlet of the second pathway; and   third dampers between the first and second pathways.   
     
     
         10 . The TRU system according to  claim 9 , wherein the controller closes the first, second and third dampers while the PCM is pre-cooled, opens the first dampers and closes the second and third dampers when the first conditions are met and closes the first dampers and opens the second and third dampers when the second conditions are met. 
     
     
         11 . The TRU system according to  claim 7 , wherein the routing assembly comprises:
 first and second piping fluidly connecting an expansion valve with the evaporator and the evaporator with a compressor, respectively;   first and second valves disposed along the first and second piping, respectively;   third and fourth piping fluidly connecting the first piping with the coil element and the coil element with the second piping, respectively; and   third and fourth valves disposed along the third and fourth piping, respectively.   
     
     
         12 . The TRU system according to  claim 11 , wherein the controller closes the first and second valves and opens the third and fourth valves while the PCM is pre-cooled, opens the first and second valves and closes the third and fourth valves when the first conditions are met and closes at least the third and fourth valves when the second conditions are met. 
     
     
         13 . The TRU system according to  claim 7 , wherein:
 the damper assembly comprises first dampers at an outlet of the first pathway, second dampers at an outlet of the second pathway and third dampers between the first and second pathways, and   the routing assembly comprises first and second piping fluidly connecting an expansion valve with the evaporator and the evaporator with a compressor, respectively, first and second valves disposed along the first and second piping, respectively, third and fourth piping fluidly connecting the first piping with the coil element and the coil element with the second piping, respectively, and third and fourth valves disposed along the third and fourth piping, respectively.   
     
     
         14 . The TRU system according to  claim 13 , wherein:
 the controller closes the first, second and third dampers, closes the first and second valves and opens the third and fourth valves while the PCM is pre-cooled,   opens the first dampers, closes the second and third dampers, opens the first and second valves and closes the third and fourth valves when the first conditions are met, and   closes the first dampers, opens the second and third dampers and closes at least the third and fourth valves when the second conditions are met.   
     
     
         15 . The TRU system according to  claim 7 , wherein the coil element comprises:
 the PCM; and   refrigerant tubes extending through the PCM and through which the refrigerant, which is directed through the coil element, flows.   
     
     
         16 . The TRU system according to  claim 7 , wherein the coil element comprises a plurality of coil element slabs between which the air flows, which are directed through the coil element, proceed. 
     
     
         17 . A method of operating a transportation refrigeration unit (TRU) system, comprising a damper assembly configured to direct air flows through first or second pathways, an evaporator disposed in the first pathway, a coil element surrounded by phase change material (PCM) and disposed in the second pathway and a routing assembly configured to direct refrigerant through the evaporator or the coil element, the method comprising:
 pre-cooling the PCM;   directing the air flows through the first pathway and the refrigerant through the evaporator when first conditions are met; and   directing the air flows through the second pathway when second conditions are met.   
     
     
         18 . The method according to  claim 17 , wherein:
 the pre-cooling of the PCM comprises pre-cooling the PCM with grid or battery power,   the first conditions are high-load conditions, and   the second conditions are low-load conditions.   
     
     
         19 . The method according to  claim 17 , wherein:
 the damper assembly comprises first dampers at an outlet of the first pathway, second dampers at an outlet of the second pathway and third dampers between the first and second pathways, and   the routing assembly comprises first and second piping fluidly connecting an expansion valve with the evaporator and the evaporator with a compressor, respectively, first and second valves disposed along the first and second piping, respectively, third and fourth piping fluidly connecting the first piping with the coil element and the coil element with the second piping, respectively, and third and fourth valves disposed along the third and fourth piping, respectively.   
     
     
         20 . The method according to  claim 19 , wherein:
 the pre-cooling of the PCM comprises closing the first, second and third dampers, closing the first and second valves and opening the third and fourth valves,   the directing when the first conditions are met comprises opening the first dampers, closing the second and third dampers, opening the first and second valves and closing the third and fourth valves, and   the directing when the second conditions are met comprises closing the first dampers, opening the second and third dampers and closing at least the third and fourth valves.