KR102297905B1 - Multiple refrigeration cycle system - Google Patents

Abstract

The present invention relates to a multi-refrigeration cycle system. According to the present invention, in the multi-refrigeration cycle system, carbon dioxide refrigerators each perform a refrigeration cycle. A brine tank stores brine inside. A brine chiller cools the brine in the brine tank to a set cooling temperature. Brine supply pipes supply the brine in the brine tank to condensers of the carbon dioxide refrigerators, respectively, and lower the condensation temperature of carbon dioxide refrigerant by exchanging heat with the carbon dioxide refrigerant in the condenser. Brine discharge pipes discharge the brine that has passed through the condensers of the carbon dioxide refrigerators, respectively, to the brine tank. Condensation temperature control devices are installed in each of the brine supply pipes, adjust the brine on the brine supply pipe side to a set temperature, and supply the brine to the corresponding condenser.

Description

Multiple refrigeration cycle system

The present invention relates to a system capable of implementing refrigeration and refrigeration functions by performing a refrigeration cycle.

As the conventional Freon (CFC)-based refrigerant is known as the main culprit of environmental destruction such as ozone layer depletion and global warming, interest in the development of alternative refrigerants to protect the environment is growing. As one of these alternative refrigerants, a refrigeration cycle using carbon dioxide is attracting attention.

However, since the critical temperature of the carbon dioxide refrigerant is as low as 31°C, the condensation temperature of the carbon dioxide refrigerant is lowered by using a dual/multiple refrigeration cycle system. The binary refrigeration cycle system consists of a low-temperature side refrigerator performing a low-temperature cycle and a high-temperature side refrigerator performing a high-temperature cycle.

In this case, the low-temperature side refrigerator uses the carbon dioxide refrigerant, and the condenser of the low-temperature side refrigerator exchanges heat with the evaporator of the high-temperature side refrigerator to lower the condensation temperature of the carbon dioxide refrigerant. However, according to the prior art, since it is common to use a Freon-based refrigerant for a high-temperature side refrigerator, continuous use is difficult due to environmental problems.

In addition, according to the prior art, when a refrigeration/refrigeration function is implemented by configuring several low-temperature side refrigerators using carbon dioxide refrigerant, the high-temperature side refrigerator is configured and operated separately for each low-temperature side refrigerator, so power consumption is considerably high, and piping and construction There is a problem that the cost is quite high.

An object of the present invention is to provide a multi-refrigeration cycle system that is environmentally friendly, reduces power consumption according to operation, and can achieve cost savings.

A multi-refrigeration cycle system according to the present invention for achieving the above object includes a plurality of carbon dioxide chillers, a brine tank, a brine chiller, brine supply pipes, brine discharge pipes, and condensation including temperature control devices.

Carbon dioxide refrigerators include a compressor for compressing a carbon dioxide refrigerant from a low-temperature and low-pressure gas to a high-temperature and high-pressure gas, a condenser for receiving and condensing the compressed carbon dioxide refrigerant through the compressor, an expansion valve for receiving the condensed carbon dioxide refrigerant through the condenser and reducing the pressure, and Each of the evaporators is provided for receiving the reduced pressure carbon dioxide refrigerant through the expansion valve, evaporating it and discharging it to the compressor, and each refrigeration cycle is performed.

The brine tank stores the brine inside. The brine chiller cools the brine in the brine tank to a set cooling temperature. The brine supply pipes supply brine in the brine tank to the condensers of the carbon dioxide refrigerators, respectively, and lower the condensation temperature of the carbon dioxide refrigerant by exchanging heat with the carbon dioxide refrigerant in the condenser. The brine discharge pipes discharge the brine that has passed through the condensers of the carbon dioxide chillers, respectively, to the brine tank. The condensing temperature control devices are installed in each of the brine supply pipes, adjust the brine on the brine supply pipe side to a set temperature, and supply it to the corresponding condenser.

Here, the condensing temperature control device can be supplied to the condenser by adjusting the brine to a set temperature by exchanging the heat medium with the brine on the brine supply pipe side.

In a further aspect, the condensing temperature control device bypasses the brine discharged to the brine discharge pipe of the carbon dioxide freezer for refrigeration of a relatively low temperature, and exchanges heat with the brine on the brine supply pipe side of the carbon dioxide freezer for refrigeration of a relatively high temperature with a heating medium. Depending on the temperature, the brine can be adjusted to the set temperature and supplied to the condenser.

The multi-refrigeration cycle system according to the present invention is environmentally friendly, reduces power consumption according to operation, and can achieve cost savings. Therefore, the multi-refrigeration cycle system according to the present invention is expected to be usefully applied to fields requiring various refrigeration effects, such as cryogenic freezing, low-temperature freezing, and low-temperature refrigeration.

1 is a block diagram of a multi-refrigeration cycle system according to an embodiment of the present invention.

The present invention will be described in detail with reference to the accompanying drawings as follows. Here, the same reference numerals are used for the same components, and repeated descriptions and detailed descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted. The embodiments of the present invention are provided in order to more completely explain the present invention to those of ordinary skill in the art. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clearer description.

1 is a block diagram of a multi-refrigeration cycle system according to an embodiment of the present invention.

Referring to FIG. 1 , the multi-refrigeration cycle system according to an embodiment of the present invention includes a plurality of carbon dioxide chillers 110 , a brine tank 120 , a brine chiller 130 , a brine chiller 130 , and a brine. It includes supply pipes 140 , brine discharge pipes 150 , and condensing temperature control devices 160 .

Each of the carbon dioxide refrigerators 110 is a refrigerator that performs a refrigeration cycle using a carbon dioxide refrigerant. Each carbon dioxide refrigerator 110 includes a compressor 111 , a condenser 112 , an expansion valve 113 , and an evaporator 114 .

The compressor 111 compresses the carbon dioxide refrigerant from low-temperature and low-pressure gas to high-temperature and high-pressure gas. The compressor 111 is connected to the condenser 112 by the refrigerant circulation pipe 110a. That is, the compressor 111 sucks in the low-temperature and low-pressure carbon dioxide refrigerant evaporated in the evaporator 114 , compresses it into a high-temperature and high-pressure gas, and then sends it to the condenser 112 . The compressor 111 may be controlled by a system controller (not shown) that controls the overall system.

The condenser 112 receives and condenses the compressed carbon dioxide refrigerant through the compressor 111 . The condenser 112 may be connected to the expansion valve 113 by the refrigerant circulation pipe 110a. The expansion valve 113 receives the condensed carbon dioxide refrigerant through the condenser 112 and depressurizes it. The expansion valve 113 may be connected to the evaporator 114 by the refrigerant circulation pipe 110a.

The evaporator 114 receives the reduced pressure carbon dioxide refrigerant through the expansion valve 113 , evaporates it, and discharges it to the compressor 111 . The carbon dioxide refrigerant takes heat from the surrounding air in the process of being evaporated in the evaporator 114 to lower the temperature of the surrounding air. At this time, the evaporator 114 may generate a freezing effect such as cryogenic freezing, low-temperature freezing, low-temperature refrigeration, etc. around it according to the heat of evaporation.

The liquid separator 115 may be installed in the refrigerant circulation pipe 110a between the evaporator 114 and the compressor 111 . The liquid separator 115 separates the liquid carbon dioxide refrigerant when the carbon dioxide refrigerant is not completely evaporated in the evaporator 114 so that only the gaseous carbon dioxide refrigerant can be sucked by the compressor 111 . Accordingly, the liquid separator 115 may prevent suction of the liquid carbon dioxide refrigerant into the compressor 111 to prevent damage to the compressor 111 .

The receiver 116 may be installed in the refrigerant circulation pipe 110a between the condenser 112 and the expansion valve 113 . The receiver 116 may absorb a change in the amount of refrigerant according to a load change by temporarily collecting the liquefied refrigerant.

The refrigerant bypass pipe 110b may be connected to the refrigerant outlet end and the refrigerant inlet end of the compressor 111 . The expansion tank 117 may be installed in the refrigerant bypass pipe 110b. The expansion tank 117 prevents the refrigerator 110 from being damaged due to a pressure increase due to the expansion of the carbon dioxide refrigerant during operation of the refrigerator 110 . Valves 118 are installed in the refrigerant bypass pipe 110b with the expansion tank 117 interposed therebetween to control the flow of the carbon dioxide refrigerant. The valve 118 may be an electromagnetic valve and may be controlled by a system controller.

The brine tank 120 stores the brine therein. Here, the brine may be made of inorganic brine such as sodium chloride or calcium chloride, or organic brine such as ethylene glycol or propylene glycol. The brine is supplied from the brine tank 120 to the condensers 112 , respectively, and serves to indirectly cool the carbon dioxide refrigerant as it heats with the carbon dioxide refrigerant in the condensers 112 .

The brine chiller 130 cools the brine in the brine tank 120 to a set cooling temperature. The brine chiller 130 may include a cooling heat exchanger 131 through which a refrigerant flows. The cooling heat exchanger 131 may be located outside the brine tank 120 . The cooling heat exchanger 131 heats the internal refrigerant with the brine circulating through the cooling circulation pipe 132 of the brine tank 120 to cool the brine to maintain it at a set cooling temperature.

As another example, although not shown, the cooling heat exchanger 131 is disposed in the brine tank 120 and comes into contact with the brine in the brine tank 120 , thereby exchanging the internal refrigerant with the brine to cool the brine.

As another example, the brine chiller 130 may include a thermoelement. A thermoelectric element is a device capable of absorbing or generating heat by using the Peltier effect, which is a phenomenon in which heat is absorbed or generated by an electric current. The thermoelectric element is installed in the brine tank 120 and controlled to absorb the heat of the brine tank 120 , thereby cooling the brine in the brine tank 120 .

The brine supply pipes 140 respectively supply the brine in the brine tank 120 to the condensers 112 of the carbon dioxide refrigerators 110 to exchange heat with the carbon dioxide refrigerant in the corresponding condenser 112, thereby lowering the condensation temperature of the carbon dioxide refrigerant.

The condenser 112 may be configured as a plate heat exchanger. In this case, the condenser 112 may be configured such that a plurality of flat plates are arranged at regular intervals to have a flow path, and the carbon dioxide refrigerant and the brine pass through one by one in the flow path. Here, the condenser 112 has a refrigerant inlet end and a refrigerant outlet end connected to the refrigerant circulation pipe 110a. The condenser 112 has a brine inlet end connected to the brine supply pipe 140 , and a brine outlet end connected to the brine outlet pipe 150 .

As such, the brine may cool the carbon dioxide refrigerant as it heats up with the carbon dioxide refrigerant while passing through a flow path different from that through which the carbon dioxide refrigerant passes in the condenser 112 .

As another example, the condenser 112 may be composed of a heat exchanger in which a flow path through which the carbon dioxide refrigerant flows and a flow path through which brine flows are coaxially formed in a corrugate shape, and thus the condenser 112 is not limited thereto.

In a further aspect, an auxiliary condenser 119 may be provided between the compressor 111 and the condenser 112 . The auxiliary condenser 119 is installed in the refrigerant circulation pipe 110a between the compressor 111 and the condenser 112 . The auxiliary condenser 119 may assist the condensation of the carbon dioxide refrigerant in the condenser 112 by first condensing the carbon dioxide refrigerant supplied from the compressor 111 as necessary. The auxiliary condenser 119 may be formed of an air-cooled condenser or the like.

The brine discharge pipes 150 discharge the brine that has passed through the condensers 112 of the carbon dioxide coolers 110 to the brine tank 120 . The brine discharge pipe 150 configures a brine circulation line together with the brine supply pipe 140 to allow the brine to circulate between the condenser 112 and the brine tank 120 .

The condensing temperature control devices 160 are respectively installed in the brine supply pipe 140 , adjust the brine on the brine supply pipe 140 side to a set temperature and supply it to the corresponding condenser 112 . Accordingly, the condensing temperature of the carbon dioxide refrigerant flowing in the condenser 112 may be controlled according to the temperature of the brine adjusted by the corresponding condensing temperature control device 160 . Accordingly, the carbon dioxide coolers 110 may generate refrigeration effects such as cryogenic freezing, low-temperature freezing, and low-temperature refrigeration by the corresponding evaporator 114 for each condensation temperature of the corresponding condensers 112 .

For example, the condensing temperature control device 160 may supply the heat medium to the condenser 112 by adjusting the brine to a set temperature by exchanging the heat medium with the brine on the side of the brine supply pipe 140 . The condensing temperature control device 160 may include a control heat exchanger 161 , a heat medium flow rate control valve 162 , a temperature sensor 163 , and a processor.

The control heat exchanger 161 may raise the temperature of the brine through heat exchange while passing the heating medium and the brine through different flow paths. The control heat exchanger 161 may be formed of a plate heat exchanger or a double tube heat exchanger.

As another example, although not shown, the control heat exchanger 161 may heat the internal heating medium with the brine in the brine supply pipe 140 while passing the corresponding brine supply pipe 140 to the inside to increase the temperature of the brine. The heating medium may be made of an antifreeze having a higher temperature than that of the brine in the brine tank 120 .

The heat medium flow rate control valve 162 controls the flow rate of the heat medium supplied to the control heat exchanger 161 . The temperature sensor 163 measures the temperature of the brine supplied to the condenser 112 . The processor controls the heat medium flow control valve 162 based on the temperature of the brine measured from the temperature sensor 163 to adjust the flow rate of the heat medium supplied to the control heat exchanger 161, so that the The temperature of the brine can be adjusted and maintained at the set temperature. The processor may be configured separately or integrated into the system controller.

The condensing temperature control device 160 bypasses the brine discharged to the brine discharge pipe 150 of the carbon dioxide freezer 110 for refrigeration of a relatively low temperature, thereby bypassing the carbon dioxide refrigerator 110 for refrigeration of a relatively high temperature together with a heating medium. By exchanging heat with the brine on the side of the brine supply pipe 140 , the brine can be adjusted to a set temperature and supplied to the condenser 112 . At this time, the bypass brine is heat-exchanged with the brine on the side of the brine supply pipe 140 in a state in which the heat is absorbed, thereby increasing the temperature of the brine on the side of the brine supply pipe 140 .

Therefore, the brine used in the carbon dioxide freezer 110 for refrigeration of a relatively low temperature is not immediately recovered to the brine tank 120, but can be used for heat dissipation by the condenser 112 of the carbon dioxide freezer 110 for refrigeration of a relatively low temperature. Therefore, it is possible to further reduce power consumption due to driving.

For example, the condensing temperature control device 160 bypasses the brine discharged to the brine discharge pipe 150 of the carbon dioxide freezer 110 for cryogenic freezing, and the carbon dioxide freezer 110 for low temperature refrigeration or a carbon dioxide freezer for low temperature refrigeration together with a heating medium ( It can exchange heat with the brine on the side of the brine supply pipe 140 of 110).

In addition, the condensation temperature control device 160 bypasses the brine discharged to the brine discharge pipe 150 of the low-temperature refrigeration carbon dioxide refrigerator 110 to bypass the brine supply pipe 140 of the low-temperature refrigeration carbon dioxide freezer 110 together with a heating medium. It can be heat-exchanged with the brine of

In this case, the condensing temperature control device 160 may further include a bypass pipe 164 and a brine flow rate control valve 165 . The bypass pipe 164 is branched from the brine discharge pipe 150 and is connected to the brine tank 120 . The control heat exchanger 161 may raise the temperature of the brine on the brine supply pipe 140 side through heat exchange while passing the bypass brine and the brine on the brine supply pipe 140 side through different flow paths.

The brine flow control valve 165 controls the flow rate of the bypass brine supplied to the control heat exchanger 161 . Here, the processor controls the brine flow control valve 162 and the heat medium flow control valve 165 based on the temperature of the brine measured from the temperature sensor 163 to control the bypass brine supplied to the control heat exchanger 161 and By adjusting the flow rate of the heating medium, the temperature of the brine supplied to the condenser 112 can be adjusted and maintained at the set temperature.

As such, the multi-refrigeration cycle system according to this embodiment uses one brine chiller 130 to control several carbon dioxide chillers 110 to produce multiple heat sources such as cryogenic freezing, low-temperature freezing, and low-temperature refrigeration in an environmentally friendly way. have. Therefore, the multi-refrigeration cycle system according to the present embodiment can reduce power consumption due to operation and reduce costs due to piping and construction, compared to the conventional example in which a high-temperature side refrigerator is configured and operated separately for each low-temperature side refrigerator.

In addition, the multi-refrigeration cycle system according to this embodiment does not directly recover the brine used in the carbon dioxide freezer 110 for refrigeration of a relatively low temperature to the brine tank 120, but a carbon dioxide freezer 110 for a relatively low temperature refrigeration. ), since it can be used for heat dissipation of the condenser 112, it is possible to further reduce power consumption according to operation.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, it will be understood that this is merely exemplary, and that various modifications and equivalent other embodiments are possible therefrom by those skilled in the art. will be able Accordingly, the true scope of protection of the present invention should be defined only by the appended claims.

110..CO2 chiller 111..Compressor
112..Condenser 113..Expansion valve
114..evaporator 120..brine tank
130..Brine chiller 140..Brine supply pipe
150..Brine discharge pipe 160..Condensation temperature control device

Claims (3)

a compressor for compressing a carbon dioxide refrigerant from a low-temperature and low-pressure gas to a high-temperature and high-pressure gas; a condenser for receiving and condensing the compressed carbon dioxide refrigerant through the compressor; an expansion valve for receiving and depressurizing the condensed carbon dioxide refrigerant through the condenser; and a plurality of carbon dioxide refrigerators each having an evaporator for receiving the reduced carbon dioxide refrigerant through the expansion valve, evaporating the refrigerant, and discharging the refrigerant to the compressor;
a brine tank that stores the brine inside;
a brine chiller for cooling the brine in the brine tank to a set cooling temperature;
brine supply pipes for respectively supplying brine in the brine tank to the condensers of the carbon dioxide refrigerators to exchange heat with the carbon dioxide refrigerant in the condenser to lower the condensation temperature of the carbon dioxide refrigerant;
brine discharge pipes for discharging the brine that has passed through the condensers of the carbon dioxide refrigerators, respectively, to the brine tank; and
Condensing temperature control devices installed in each of the brine supply pipes to adjust the brine on the brine supply pipe side to a set temperature and supply it to the corresponding condenser; includes,
The condensing temperature control device,
By heat-exchanging the heating medium with the brine on the brine supply pipe side, the brine is adjusted to a set temperature and supplied to the condenser;
By bypassing the brine discharged to the brine discharge pipe of the carbon dioxide freezer for refrigeration at a relatively low temperature, the brine is adjusted to the set temperature by exchanging heat with the brine on the brine supply pipe side of the carbon dioxide freezer for refrigeration at a relatively high temperature with the heating medium. Multi-refrigeration cycle system, characterized in that the supply to the condenser. delete delete

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