Transport refrigeration unit with battery boost

Abstract

A transport refrigeration unit (26) includes a compressor (58) constructed and arranged to compress a refrigerant and an electric compressor motor configured to drive the compressor. A generator (54) of the unit is configured to provide electric power to the compressor motor during standard set point conditions, and an energy storage device of the unit is configured to supplement the electric power to the compressor motor during temperature pulldown conditions.

1 . A transport refrigeration unit comprising:
 a compressor constructed and arranged to compress a refrigerant;   an electric compressor motor configured to drive the compressor;   a generator configured to provide electric power to the compressor motor during standard set point conditions; and   an energy storage device configured to supplement the electric power to the compressor motor during temperature pulldown conditions   at least one heat exchanger operatively coupled to the compressor;   at least one fan configured to provide air flow over the at least one heat exchanger; and   at least one electric fan motor configured to drive the at least one fan, and wherein the generator is configured to provide electric power to the at least one fan motor during standard set point conditions.   
     
     
         2 - 3 . (canceled) 
     
     
         4 . The transport refrigeration unit set forth in  claim 1 , wherein the energy storage device is configured to supplement the electric power to the at least one fan motor during temperature pulldown conditions. 
     
     
         5 . The transport refrigeration unit set forth in  claim 4 , wherein the at least one heat exchanger includes an evaporator heat exchanger, the at least one fan includes an evaporator fan, and the at least one electric fan motor includes an evaporator fan motor. 
     
     
         6 . The transport refrigeration unit set forth in  claim 5 , wherein the at least one heat exchanger includes a condenser heat exchanger, the at least one fan includes a condenser fan, and the at least one electric fan motor includes a condenser fan motor. 
     
     
         7 . The transport refrigeration unit set forth in  claim 1 , wherein the refrigerant is a natural refrigerant. 
     
     
         8 . The transport refrigeration unit set forth in  claim 6 , wherein the refrigerant is a natural refrigerant. 
     
     
         9 . The transport refrigeration unit set forth in  claim 1 , wherein the energy storage device is a battery. 
     
     
         10 . The transport refrigeration unit set forth in  claim 9 , wherein the battery has a voltage potential with a range of about 48V to 250V. 
     
     
         11 . A method of operating a transport refrigeration unit comprising:
 utilizing one of an electric generator and an energy storage device to provide electric power generally during steady state conditions; and   providing supplemental power from the other of the electric generator and the energy storage device during a temperature pull down state.   
     
     
         12 . The method set forth in  claim 11 , wherein the energy storage device is a battery. 
     
     
         13 . The method set forth in  claim 11 , wherein the supplemental power is provided to a compressor motor. 
     
     
         14 . The method set forth in  claim 11 , wherein the compressor motor is an alternating current motor and the supplemental power is delivered through an inverter. 
     
     
         15 . The method set forth in  claim 14 , wherein the electric generator has a maximum power output that is less than a system power load during the temperature pull down state. 
     
     
         16 . The method set forth in  claim 11  further comprising:
 charging the energy storage device by the electric generator during part load operating conditions. 
 
     
     
         17 . The method set forth in  claim 11  further comprising:
 driving the electric generator by a combustion engine. 
 
     
     
         18 . The method set forth in  claim 14 , wherein an evaporator fan motor and a condenser fan motor of the transport refrigeration unit are direct current motors. 
     
     
         19 . The method set forth in  claim 11 , wherein the electric generator provides the power to a compressor motor, an evaporator fan motor and a condenser fan motor during steady state conditions. 
     
     
         20 . The method set forth in  claim 11 , wherein the energy storage device provides the power to a compressor motor, an evaporator fan motor and a condenser fan motor during steady state conditions. 
     
     
         21 . A transport refrigeration unit comprising:
 a compressor constructed and arranged to compress a refrigerant;   an electric compressor motor configured to drive the compressor;   a generator configured to provide electric power to the compressor motor during standard set point conditions; and   an energy storage device configured to supplement the electric power to the compressor motor during temperature pulldown conditions;   at least one heat exchanger operatively coupled to the compressor;   at least one fan configured to provide air flow over the at least one heat exchanger; and   at least one electric fan motor configured to drive the at least one fan, and wherein the energy storage device is configured to provide electric power to the at least one fan motor during standard set point conditions.