Modular refrigeration system, e.g., for ships

Abstract

A self-enclosed modular refrigeration unit for refrigeration system comprises compressor adapted to compress a refrigerant. A heat exchanger is connected to a cooling water network to condense the refrigerant with cooling water. A suction line is connected to a suction side of the compressor and adapted to provide a feed of refrigerant to the compressor. A discharge line is connected to a discharge side of the compressor and to the heat exchanger to direct compressed refrigerant to the heat exchanger. A head pressure control valve is in the discharge line downstream of the heat exchanger to control an upstream pressure. A casing encloses the compressor, the heat exchanger, the head pressure control valve. An outlet line has an outlet end downstream of the head pressure control valve adapted to output cooling refrigerant having passed through the head pressure control valve. An inlet end is upstream of the suction line to provide a feed of refrigerant to the compressor.

1 . A self-enclosed modular refrigeration unit for refrigeration system comprising:
 at least one compressor adapted to compress a refrigerant;   a heat exchanger adapted to be connected to a cooling water network to condense the refrigerant with cooling water;   a suction line connected to a suction side of the compressor and adapted to provide a feed of refrigerant to the compressor;   a discharge line connected to a discharge side of the compressor and to the heat exchanger to direct compressed refrigerant to the heat exchanger;   a head pressure control valve in the discharge line downstream of the heat exchanger to control an upstream pressure;   a casing enclosing the compressor, the heat exchanger, the head pressure control valve;   an outlet line having an outlet end downstream of the head pressure control valve adapted to output cooling refrigerant having passed through the head pressure control valve; and   an inlet end upstream of the suction line adapted to provide a feed of refrigerant to the compressor.   
     
     
         2 . The self-enclosed modular refrigeration unit according to  claim 1 , wherein the discharge line diverges into a subline connected to the heat exchanger and then to the head pressure control valve, and another subline bypassing the heat exchanger to be connected to the head pressure control valve. 
     
     
         3 . The self-enclosed modular refrigeration unit according to  claim 1 , further comprising a closing valve at the outlet end, the closing valve being on a portion of the outlet line outside of the casing. 
     
     
         4 . The self-enclosed modular refrigeration unit according to  claim 1 , further comprising a closing valve at the inlet end, the closing valve being on a portion of the suction line outside of the casing. 
     
     
         5 . The self-enclosed modular refrigeration unit according to  claim 1 , further comprising a receiver in the outlet line, the receiver enclosed in the casing. 
     
     
         6 . The self-enclosed modular refrigeration unit according to  claim 1 , further comprising a suction accumulator in the suction line, the suction accumulator enclosed in the casing. 
     
     
         7 . The self-enclosed modular refrigeration unit according to  claim 1 , wherein the at least one compressor is one of a hermetic reciprocating compressor or a scroll compressor. 
     
     
         8 . The self-enclosed modular refrigeration unit according to  claim 1 , wherein the heat exchanger is a coaxial water-cooled condenser. 
     
     
         9 . The self-enclosed modular refrigeration unit according to  claim 1 , wherein open ends of the heat exchanger adapted to be connected to the cooling water network project out of the casing, and are provided with closing valves. 
     
     
         10 . A watercraft comprising:
 the self-enclosed modular refrigeration unit according to  claim 1 ,   the cooling water network connected to the heat exchanger for circulating cooling water in the heat exchanger;   an enclosure to be refrigerated; and   a refrigeration unit cooler permanently in the watercraft and having an inlet connectable to the outlet line of the self-enclosed modular refrigeration unit for receiving cooling refrigerant, an expansion valve, an evaporator coil in the enclosure and an an outlet connectable to the suction line of the self-enclosed modular refrigeration unit for returning refrigerant to the self-enclosed modular refrigeration unit.   
     
     
         11 . The watercraft according to  claim 10 , further comprising closing valves at the inlet and at the outlet of the refrigeration unit cooler. 
     
     
         12 . The watercraft according to  claim 10 , further comprising flexible pipes between the inlet of the refrigeration unit cooler and the outlet line of the self-enclosed modular refrigeration unit, and between the outlet of the refrigeration unit cooler and the suction line of the self-enclosed modular refrigeration unit. 
     
     
         13 . The watercraft according to  claim 10 , further comprising closing valves at the inlet and at the outlet of the cooling water network. 
     
     
         14 . The watercraft according to  claim 10 , further comprising flexible pipes between cooling water network and the heat exchanger. 
     
     
         15 . The watercraft according to  claim 10 , wherein the expansion valve is an electronic expansion valve, and further wherein a control of the expansion valve is part of the refrigeration unit couler permanently in the watercraft. 
     
     
         16 . A method for replacing a modular refrigeration unit with another, comprising:
 closing a fluid communication between a refrigerant receiver of a first modular refrigeration unit and an evaporator;   operating a compressor of the first modular refrigeration unit upstream of the refrigerant receiver to collect refrigerant in the refrigerant receiver;   upon reaching a given level of refrigerant in the refrigerant receiver, stopping the compressor;   closing a fluid communication between the evaporator and the compressor;   disconnecting a refrigeration circuit of the first modular refrigeration unit from a circuit of the evaporator, and a heat exchanger of the first modular refrigeration unit from a cooling water network; and   replacing the first modular refrigeration unit with a second modular refrigeration unit;   wherein the steps are performed in any appropriate order.   
     
     
         17 . The method according to  claim 16 , wherein replacing the first modular refrigeration unit with a second modular refrigeration unit comprises:
 connecting a refrigeration circuit of the second modular refrigeration unit to the circuit of the evaporator, and a heat exchanger of the second modular refrigeration unit to the cooling water network;   opening a fluid communication between a refrigerant receiver of the second modular refrigeration unit and the evaporator,   opening a fluid communication between the evaporator and a compressor of the second modular refrigeration unit; and   starting the compressor;   wherein the steps are performed in any appropriate order.