Refrigeration and heating system

Abstract

A method of operating a refrigeration and heating system ( 2 a, 2 b ) comprises: circulating a refrigerant through a refrigeration circuit ( 4 ) which comprises in the direction of flow of the circulating refrigerant: at least one compressor ( 6 a, 6 b, 6 c ); a refrigeration circuit side ( 8 a ) of a coupling heat exchanger ( 8 ); at least one gas cooler ( 10 ); at least one expansion device ( 12, 14 ); and at least one evaporator ( 16 ); circulating a heating fluid through a heating circuit ( 20 ) which comprises a heating circuit side ( 8 b ) of the coupling heat exchanger ( 8 ) and at least one heat consumer ( 22 ); wherein the coupling heat exchanger ( 8 ) is configured for transferring heat from the circulating refrigerant to the circulating heating fluid. The method further includes increasing the temperature of the refrigerant entering the at least one gas cooler ( 10 ) in order to meet increased heating demands by allowing at least a portion of the heating fluid to flow directly from an outlet to an inlet of the heating circuit side ( 8 b ) of the coupling heat exchanger ( 8 ) bypassing the at least one heat consumer ( 22 ) or by allowing at least a portion of the refrigerant circulating through the refrigeration circuit ( 4 ) to bypass the coupling heat exchanger ( 8 ).

1 . Refrigeration and heating system ( 2   a ) comprising:
 a refrigeration circuit ( 4 ) which comprises in the direction of flow of a circulating refrigerant:   at least one compressor ( 6   a ,  6   b ,  6   c );   a refrigeration circuit side ( 8   a ) of a coupling heat exchanger ( 8 );   at least one gas cooler ( 10 );   at least one expansion device ( 12 ,  14 );   and at least one evaporator ( 16 );   a heating circuit ( 20 ) which comprises:   a heating circuit side ( 8   b ) of the coupling heat exchanger ( 8 );   at least one heat consumer ( 22 ); and   at least one controllable heating fluid bypass valve ( 23 ) allowing   
       at least a portion of the heating fluid to flow directly from an outlet to an inlet of the heating circuit side ( 8   b ) of the coupling heat exchanger ( 8 ) bypassing the at least one heat consumer ( 22 );
 wherein the coupling heat exchanger ( 8 ) is configured for transferring heat from the refrigerant flowing through the refrigeration circuit side ( 8   a ) to the heating fluid flowing through the heating circuit side ( 8   b ); and 
 wherein the refrigeration and heating system further comprises a control unit ( 38 ), which is configured for selectively opening the at least one heating fluid bypass valve ( 23 ) for increasing the temperature of the refrigerant leaving the coupling heat exchanger (S) in order to meet increased heating demands. 
 
     
     
         2 . Refrigeration and heating system ( 2   a ) of  claim 1 , wherein the control unit ( 38 ) is further configured to increase the performance of the at least one compressor ( 6   a ,  6   b ,  6   c ) when the at least one heating fluid bypass valve ( 23 ) is opened. 
     
     
         3 . Refrigeration and heating system ( 2   a ) of  claim 1 , the heating fluid bypass valve ( 23 ) is a continuously adjustable valve. 
     
     
         4 . Refrigeration and heating system ( 2   b ) comprising:
 a refrigeration circuit ( 4 ) which comprises in the direction of flow of a circulating refrigerant:   at least one compressor ( 6   a ,  6   b ,  6   c );   a heat exchanger bypass valve ( 34 );   a refrigeration circuit side ( 8   a ) of a coupling heat exchanger ( 8 );   at least one gas cooler ( 10 );   at least one expansion device ( 12 ,  14 );   and at least one evaporator ( 16 );   a heating circuit ( 20 ) which comprises:   a heating circuit side ( 8   b ) of the coupling heat exchanger ( 8 );   and at least one heat consumer ( 22 );   wherein the coupling heat exchanger ( 8 ) is configured for transferring heat from the refrigerant flowing through the refrigeration circuit side ( 8   a ) to the heating fluid flowing through the heating circuit side ( 8   b );   wherein the heat exchanger bypass valve ( 34 ) is provided as an adjustable mixing valve ( 34 ); and   wherein the refrigeration and heating system further comprises a control unit ( 38 ), which is configured for selectively controlling the heat exchanger bypass valve ( 34 ) for allowing at least a portion of the refrigerant to bypass the refrigeration circuit side ( 8   a ) of a coupling heat exchanger ( 8 ) for increasing the temperature of the refrigerant upstream the gas cooler ( 10 ).   
     
     
         5 . Refrigeration and heating system ( 2   a ,  2   b ) of  claim 1 , wherein the refrigeration circuit ( 4 ) comprises a gas cooler bypass line ( 18 ) including a gas cooler bypass valve ( 24 ) allowing refrigerant to selectively bypass the gas cooler ( 10 ). 
     
     
         6 . Refrigeration and heating system ( 2   a ,  2   b ) of  claim 1  further comprising a refrigerant receiver ( 26 ) downstream of the gas cooler ( 10 ). 
     
     
         7 . Refrigeration and heating system ( 2   a ,  2   b ) of  claim 6 , further comprising a high pressure control device ( 12 ) upstream of the refrigerant receiver ( 26 ). 
     
     
         8 . Refrigeration and heating system ( 2   a ,  2   b ) of  claim 6 , further comprising a flash gas line ( 28 ) fluidly connecting an upper portion of the refrigerant receiver ( 26 ) with the inlet line ( 7   a ,  7   b ,  7   c ) of the at least one compressor ( 6   a ,  6   b ,  6   c ). 
     
     
         9 . Refrigeration and heating system ( 2   a ,  2   b ) of  claim 8  further comprising a flash gas valve ( 30 ) in the flash gas line ( 28 ). 
     
     
         10 . Refrigeration and heating system ( 2   a ,  2   b ) of  claim 8 , further comprising a flash gas heat exchanger ( 32 ) providing heat exchange between the flash gas flowing through the flash gas line ( 28 ) and refrigerant leaving from the bottom of the receiver ( 26 ). 
     
     
         11 . Refrigeration and heating system ( 2   a ,  2   b ) of  claim 7 , further comprising an additional flash gas compressor ( 6   d ) and a flash gas compressor line ( 29 ) fluidly connecting an upper portion of the refrigerant receiver ( 26 ) with an inlet line ( 7   d ) of the additional flash gas compressor ( 6   d ). 
     
     
         12 . Refrigeration and heating system ( 2   a ,  2   b ) of  claim 1 , further comprising at least one of a refrigerant pressure sensor ( 40 ), a refrigerant temperature sensor ( 42 ), a heating fluid temperature sensor ( 44 ) and an ambient air temperature sensor ( 46 ) for allowing the control unit ( 38 ) to control the compressors ( 6   a ,  6   b ,  6   c ) and/or the heating fluid bypass valve ( 23 ) based on the measured temperatures and/or pressures. 
     
     
         13 . Refrigeration and heating system ( 2   a ,  2   b ) of  claim 1 , wherein the refrigerant comprises carbon dioxide. 
     
     
         14 . Method of operating a refrigeration and heating system ( 2   a ,  2   b ) comprising:
 circulating a refrigerant through a refrigeration circuit ( 4 ) which comprises in the direction of flow of the circulating refrigerant:
 at least one compressor ( 6   a ,  6   b ,  6   c ); 
 a refrigeration circuit side ( 8   a ) of a coupling heat exchanger ( 8 ); 
 at least one gas cooler ( 10 ); 
 at least one expansion device ( 12 ,  14 ); and 
 at least one evaporator ( 16 ); 
   circulating a heating fluid through a heating circuit ( 20 ) which comprises:
 a heating circuit side ( 8   b ) of the coupling heat exchanger ( 8 ); and at least one heat consumer ( 22 ); 
   wherein the coupling heat exchanger ( 8 ) is configured for transferring heat from the circulating refrigerant to the circulating heating fluid; and   the method includes increasing the temperature of the refrigerant entering the at least one gas cooler ( 10 ) in order to meet increased heating demands by allowing at least a portion of the heating fluid to flow directly from an outlet to an inlet of the heating circuit side ( 8   b ) of the coupling heat exchanger ( 8 ) bypassing the at least one heat consumer ( 22 ) or by allowing at least a portion of the refrigerant circulating through the refrigeration circuit ( 4 ) to bypass the coupling heat exchanger ( 8 ).   
     
     
         15 . Method of operating a refrigeration and heating system ( 2   a ) according to  claim 14 , wherein the method includes controlling a controllable valve ( 23 ), which is connected between the outlet and the inlet of the heating circuit side ( 8   b ) of the coupling heat exchanger ( 8 ). 
     
     
         16 . Method of operating a refrigeration and heating system ( 2   b ) according to  claim 14 , wherein the method includes controlling an adjustable heat exchanger bypass valve ( 34 ), which is configured for allowing refrigerant to bypass the refrigeration circuit side ( 8   a ) of the coupling heat exchanger ( 8 ). 
     
     
         17 . Method of operating a refrigeration and heating system ( 2   a ,  2   b ) according to  claim 14 , wherein the method includes increasing the performance of the at least one compressor ( 6   a ,  6   b ,  6   c ). 
     
     
         18 . Method of operating a refrigeration and heating system ( 2   a ,  2   b ) according to  claim 14 , wherein the method comprises measuring the temperature of the refrigerant circulating within the refrigeration circuit ( 4 ) and/or the temperature of the heating fluid circulating within the heating circuit ( 20 ) and controlling the controllable valve ( 23 ), the adjustable heat exchanger bypass valve ( 34 ) and/or the at least one compressor ( 6   a ,  6   b ,  6   c ) based on the measured temperature of the circulating refrigerant and/or the measured temperature of the heating fluid, respectively. 
     
     
         19 . Method of operating a refrigeration and heating system ( 2   a ,  2   b ) according to  claim 14 , wherein the method comprises measuring the ambient temperature and controlling the controllable valve ( 23 ), the adjustable heat exchanger bypass valve ( 34 ) and/or the at least one compressor ( 6   a ,  6   b ,  6   c ) based on the measured ambient temperature. 
     
     
         20 . Method of operating a refrigeration and heating system ( 2   a ,  2   b ) according to  claim 14 , wherein the method comprises measuring the pressure of the refrigerant circulating within the refrigeration circuit ( 4 ) and controlling the controllable bypass valve ( 23 ), the adjustable heat exchanger bypass valve ( 34 ) and/or the at least one compressor ( 6   a ,  6   b ,  6   c ) based on the measured pressure in order to set the point of operation of the refrigeration circuit ( 4 ). 
     
     
         21 . Method of operating a refrigeration and heating system ( 2   a ,  2   b ) according to  claim 14 , wherein the method comprises to determine the heating and/or cooling demands and controlling the controllable valve ( 23 ), the adjustable heat exchanger bypass valve ( 34 ) and/or the at least one compressor ( 6   a ,  6   b ,  6   c ) based on said demands. 
     
     
         22 . Method of operating a refrigeration and heating system ( 2   a ,  2   b ) according to  claim 14 , wherein the refrigerant comprises carbon dioxide and the refrigeration circuit ( 4 ) is at least partly operated under transcritical conditions.