Storage of excess heat in cold side of heat engine

Abstract

Extra heat in a closed cycle power generation system, such as a reversible closed Brayton cycle system, may be dissipated between discharge and charge cycles. An extra cooling heat exchanger may be added on the discharge cycle and disposed between a cold side heat exchanger and a compressor inlet. Additionally or alternatively, a cold thermal storage medium passing through the cold side heat exchanger may be allowed to heat up to a higher temperature during the discharge cycle than is needed on input to the charge cycle and the excess heat then dissipated to the atmosphere.

1 . An energy system comprising:
 a compressor;   a hot side heat exchanger;   a turbine;   a cold side heat exchanger;   a working fluid circulating in a closed cycle path in both charge and discharge modes, the working fluid circulating through, in sequence, the compressor, the hot side heat exchanger, the turbine, and the cold side heat exchanger in the discharge mode;   a cold side thermal storage (“CTS”) medium;   a first CTS tank;   a second CTS tank; and   a first flow path configured to flow CTS medium from the first CTS tank, through the cold side heat exchanger, to the second CTS tank, wherein the cold side heat exchanger is configured to communicate heat transfer between the CTS medium and the working fluid; and   a cooling heat exchange system configured to remove heat from the working fluid in the discharge mode.   
     
     
         2 . The energy system of  claim 1 , wherein the working fluid circulates in the closed cycle path in the same direction in both the charge mode and the discharge mode. 
     
     
         3 . The energy system of  claim 1 , further comprising:
 a first hot side thermal storage (“HTS”) tank;   a second HTS tank; and   an HTS medium flowing from the first HTS tank, through the hot side heat exchanger, and to the second HTS tank.   
     
     
         4 . The system of  claim 3 , wherein the cooling heat exchange system comprises a cooling tower. 
     
     
         5 . The energy system of  claim 3 , wherein the cooling heat exchange system includes a radiator for expelling heat to the environment. 
     
     
         6 . The energy system of  claim 1 , wherein in the discharge mode, the cooling heat exchange system removes heat from the working fluid before heat transfer between the CTS medium and the working fluid via the cold side heat exchanger. 
     
     
         7 . The energy system of  claim 6 , wherein the cooling heat exchange system removes heat from the working fluid, and the working fluid with heat removed is circulated through the cold side heat exchanger to further remove heat. 
     
     
         8 . The energy system of  claim 6 , wherein the heat removed from the working fluid via the cooling heat exchange system is excess heat. 
     
     
         9 . The energy system of  claim 8 , wherein excess heat includes heat of the working fluid having higher temperature during the discharge mode than required for the charge mode. 
     
     
         10 . A method comprising:
 in a closed cycle system operable in a power generation mode and an energy charge mode, circulating a working fluid through a closed cycle fluid path including, in sequence, a compressor, a hot side heat exchanger, a turbine, and a cold side heat exchanger in the power generation mode;   flowing the working fluid through a cooling heat exchange system to remove excess heat; and   flowing a cold side thermal storage (“CTS”) medium from a first CTS tank, through the cold side heat exchanger to a second CTS tank to remove heat from the working fluid.   
     
     
         11 . The method of  claim 10 , wherein the working fluid circulates in the closed cycle path in the same direction in both the energy charge mode and the power generation mode. 
     
     
         12 . The method of  claim 10 , further comprising varying the flow rate of CTS medium from the first CTS tank to the second CTS tank. 
     
     
         13 . The method of  claim 10 , further comprising flowing a hot side thermal storage (“HTS”) from a first HTS tank, through the hot side heat exchanger, and to the second HTS tank. 
     
     
         14 . The method of  claim 10 , wherein the cooling heat exchange system comprises a cooling tower. 
     
     
         15 . The method of  claim 10 , wherein the cooling heat exchange system includes a radiator for expelling heat to the environment. 
     
     
         16 . The method of  claim 10 , wherein in the power generation mode, the cooling heat exchange system removes heat from the working fluid before heat transfer between the CTS medium and the working fluid via the cold side heat exchanger. 
     
     
         17 . The method of  claim 16 , wherein the cooling heat exchange system removes heat from the working fluid, and the working fluid with heat removed is circulated through the cold side heat exchanger to further remove heat. 
     
     
         18 . The energy system of  claim 16 , wherein the heat removed from the working fluid via the cooling heat exchange system is excess heat. 
     
     
         19 . The energy system of  claim 18 , wherein excess heat includes heat of the working fluid having higher temperature during the discharge mode than required for the charge mode.