Refrigeration system with heat recovery
A refrigeration system with heat recovery includes a vapor compression circuit having at least one compressor, a gas cooler, a receiver, a first expansion device fluidly connected between a first refrigerant path of the gas cooler and the receiver, a second expansion device fluidly connected between the receiver and a second refrigerant path of the gas cooler, and at least one evaporator. The refrigeration system includes a heat exchanger configured to exchange heat between refrigerant flowing in the vapor compression circuit and a fluid flowing in a hot fluid circuit. The gas cooler is arranged such that heat from refrigerant flowing in the first refrigerant path of the gas cooler is transferred to refrigerant flowing in the second refrigerant path of the gas cooler when the second expansion device is open and allowing refrigerant flow from the receiver to the second refrigerant path of the gas cooler.
1 . A refrigeration system with heat recovery comprising:
a vapor compression circuit comprising:
at least one compressor;
a heat exchanger configured to exchange heat between refrigerant flowing in the vapor compression circuit and a fluid flowing in a hot fluid circuit;
a valve configured to control a flow of refrigerant through the heat exchanger from the at least one compressor;
a gas cooler having a first refrigerant path and a second refrigerant path;
a receiver;
a first expansion device fluidly connected between the first refrigerant path of the gas cooler and the receiver;
a second expansion device fluidly connected between the receiver and the gas cooler; and
at least one evaporator;
a refrigeration controller configured to control the at least one compressor, the valve, the first expansion device and the second expansion device;
wherein the gas cooler is arranged such that heat from refrigerant flowing in the first refrigerant path of the gas cooler is transferred to refrigerant flowing in the second refrigerant path of the gas cooler when the second expansion device is open and allowing refrigerant flow from the receiver to the second refrigerant path of the gas cooler.
2 . The refrigeration system according to claim 1 , wherein the refrigerant in the vapor compression circuit comprises carbon dioxide.
3 . The refrigeration system according to claim 1 , wherein the at least one compressor comprises two or more compressors.
4 . The refrigeration system according to claim 1 , wherein the at least one compressor comprises a medium temperature compressor and a low temperature compressor.
5 . The refrigeration system according to claim 1 , wherein the at least one evaporator comprises two or more evaporators.
6 . The refrigeration system according to claim 1 , wherein the at least one evaporator comprises a medium temperature evaporator and a low temperature evaporator.
7 . The refrigeration system according to claim 6 , further comprising:
a third expansion device fluidly connected between the receiver and the medium temperature evaporator; and
a fourth expansion device fluidly connected between the receiver and the low temperature evaporator;
wherein the controller is configured to control the third expansion device and the fourth expansion device.
8 . The refrigeration system according to claim 1 , wherein the valve is a three-way valve.
9 . The refrigeration system according to claim 1 , wherein the refrigeration controller is configured to control the valve, the first expansion device and/or the second expansion device based on a level of heat demand in a heat demand signal received by the refrigeration controller.
10 . The refrigeration system according to claim 9 , wherein, when the level of heat demand is a first level, the refrigeration controller is configured to control the valve to move from a first position where no refrigerant is flowing through the heat exchanger to a second position where refrigerant is flowing through the heat exchanger while the at least one compressor is operating.
11 . The refrigeration system according to claim 10 , wherein, when the level of heat demand is a second level, the refrigeration controller is configured to control the first expansion device to increase pressure in the first refrigerant path of the gas cooler by closing the first expansion device or reducing an opening degree of the first expansion device.
12 . The refrigeration system according to claim 11 , wherein, when the level of heat demand is a third level, the refrigeration controller is configured to control the second expansion device to open, thereby allowing refrigerant to flow from the receiver to the second refrigerant path of the gas cooler.
13 . The refrigeration system according to claim 1 , wherein the refrigeration controller is configured to variably open the second expansion device based on a level of heat demand of a heat demand signal received by the refrigeration controller.
14 . A refrigeration controller for controlling a refrigeration system, the refrigeration system including:
a vapor compression circuit that includes:
at least one compressor;
a heat exchanger configured to exchange heat between refrigerant flowing in the vapor compression circuit and a fluid flowing in a hot fluid circuit;
a valve configured to control a flow of refrigerant through the heat exchanger from the at least one compressor;
a gas cooler having a first refrigerant path and a second refrigerant path;
a receiver;
a first expansion device fluidly connected between the first refrigerant path of the gas cooler and the receiver;
a second expansion device fluidly connected between the receiver and the gas cooler; and
at least one evaporator;
wherein the gas cooler is arranged such that heat from refrigerant flowing in the first refrigerant path of the gas cooler is transferred to refrigerant flowing in the second refrigerant path of the gas cooler when the second expansion device is open and allowing refrigerant flow from the receiver to the second refrigerant path of the gas cooler;
the refrigeration controller comprising:
a processor configured to generate and send signals for controlling the at least one compressor, the valve, the first expansion device and the second expansion device.
15 . The refrigeration controller according to claim 14 , wherein the processor is configured to control the valve, the first expansion device and/or the second expansion device based on a level of heat demand in a heat demand signal received by the refrigeration controller.
16 . The refrigeration controller according to claim 15 , wherein, when the level of heat demand is a first level, the processor is configured to control the valve to move from a first position where no refrigerant is flowing through the heat exchanger to a second position where refrigerant is flowing through the heat exchanger while the at least one compressor is operating.
17 . The refrigeration controller according to claim 16 , wherein, when the level of heat demand is a second level, the processor is configured to control the first expansion device to increase pressure in the first refrigerant path of the gas cooler by closing the first expansion device or reducing an opening degree of the first expansion device.
18 . The refrigeration controller according to claim 17 , wherein, when the level of heat demand is a third level, the processor is configured to control the second expansion device to open, thereby allowing refrigerant to flow from the receiver to the second refrigerant path of the gas cooler.
19 . The refrigeration controller according to claim 14 , wherein the processor is configured to variably open the second expansion device based on a level of heat demand of a heat demand signal received by the refrigeration controller.