KR102551875B1 - Hybrid carbon dioxide heat pump - Google Patents

Abstract

The present invention relates to a hybrid carbon dioxide heat pump. The compressor compresses the carbon dioxide refrigerant from a low-temperature, low-pressure gas to a high-temperature, high-pressure gas. The condenser heats the water supplied from the hot water storage tank by exchanging heat with the refrigerant supplied from the compressor, and then discharges the water into the hot water storage tank. The expansion valve receives the condensed refrigerant through the condenser and depressurizes it. The evaporator receives the reduced pressure refrigerant through an expansion valve, evaporates it, and discharges it to the compressor. The water supply source for the evaporator supplies water to the evaporator so that the refrigerant in the evaporator exchanges heat with water heated by renewable energy or waste heat. The evaporation temperature sensor measures the evaporation temperature of the refrigerant supplied from the expansion valve to the evaporator. Based on the information measured from the evaporation temperature sensor, the controller changes the evaporation temperature of the refrigerant to a set value by controlling the water supply for the evaporator to adjust the amount of water supplied to the evaporator.

Description

Hybrid carbon dioxide heat pump

The present invention relates to a heat pump capable of producing high-temperature water using a carbon dioxide refrigerant.

In general, a large amount of hot water is required in places such as bathhouses, saunas, or accommodations. For this purpose, a combustion-type domestic hot water system that heats water with fossil fuels, an electric hot water system that supplies hot water by heating water with electricity, and a heat pump-type domestic hot water system that supplies hot water by heating water with a heat pump are used. there is. A heat pump refers to a cooling/heating device that transfers a low-temperature heat source to a high temperature or a high-temperature heat source to a low-temperature temperature by using heat or condensation heat of a refrigerant.

Recently, as carbon neutrality to prevent global warming has become a global trend, a heat pump system has emerged as the most efficient alternative as an effective HVAC (Heating, Ventilation and Air Conditioning) technology that saves energy and reduces greenhouse gas emissions. In addition, as the use of existing refrigerant gas (F-gas) is restricted due to international environmental regulations, interest in heat pump systems replaced with new refrigerants and natural refrigerants is increasing. As one of these alternative refrigerants, a heat pump using a carbon dioxide refrigerant is attracting attention.

In the heat pump type hot water supply system, evaporation efficiency is significantly reduced when the temperature difference between the refrigerant in the evaporator and the surrounding heating medium is insignificant during the cycle. Existing imported carbon dioxide heat pump type domestic hot water systems generally exchange heat from refrigerant in the evaporator to ambient air heat, and thus, a problem in that efficiency rapidly decreases when the air temperature drops below zero.

Registered Patent Publication No. 10-1348826 (2013.05.20, published)

An object of the present invention is to provide a hybrid carbon dioxide heat pump capable of increasing evaporation efficiency and increasing energy efficiency by using only a necessary amount of heat.

A hybrid carbon dioxide heat pump according to the present invention for achieving the above object includes a hot water storage tank, a compressor, a condenser, an expansion valve, an evaporator, a water source for the evaporator, an evaporation temperature sensor, and a controller. The compressor compresses the carbon dioxide refrigerant from a low-temperature, low-pressure gas to a high-temperature, high-pressure gas. The condenser heats the water supplied from the hot water storage tank by exchanging heat with the refrigerant supplied from the compressor, and then discharges the water into the hot water storage tank. The expansion valve receives the condensed refrigerant through the condenser and depressurizes it. The evaporator receives the reduced pressure refrigerant through an expansion valve, evaporates it, and discharges it to the compressor. The water supply source for the evaporator supplies water to the evaporator so that the refrigerant in the evaporator exchanges heat with water heated by renewable energy or waste heat. The evaporation temperature sensor measures the evaporation temperature of the refrigerant supplied from the expansion valve to the evaporator. Based on the information measured from the evaporation temperature sensor, the controller changes the evaporation temperature of the refrigerant to a set value by controlling the water supply for the evaporator to adjust the amount of water supplied to the evaporator.

According to the present invention, evaporation efficiency can be increased by supplying water heated by renewable energy or waste heat to the evaporator, and energy efficiency can be increased by using only the amount of heat required to change the evaporation temperature to a set value.

In addition, according to the present invention, since the set value of the evaporation temperature can be changed according to the inlet temperature of the condenser and the discharge temperature of the refrigerant can be optimized by maintaining it below the set value, the condenser can operate stably even if the inlet temperature is high. In addition, according to the present invention, it is possible to operate stably by preventing overpressure of the refrigerant that may occur during operation. Therefore, the present invention has an effect of replacing the import of carbon dioxide heat pumps, which are currently entirely dependent on imports.

1 is a block diagram of a hybrid carbon dioxide heat pump according to an embodiment of the present invention.

The present invention will be described in detail with reference to the accompanying drawings. 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 are omitted.

Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clarity.

1 is a block diagram of a hybrid carbon dioxide heat pump according to an embodiment of the present invention.

Referring to FIG. 1, a hybrid carbon dioxide heat pump 100 according to an embodiment of the present invention includes a hot water storage tank 110, a compressor 120, a condenser 130, an expansion valve 140, and an evaporator. 150, a water source for the evaporator 160, an evaporation temperature sensor 170, and a controller 180.

The hot water storage tank 110 stores water to be supplied to the condenser 130 and water heated by the condenser 130 . A replenishment water supply pipe 112 is connected to the hot water storage tank 110 to replenish water. A hot water discharge pipe 113 may be connected to the hot water storage tank 110 to discharge the stored hot water to the outside.

The hot water storage tank 110 and the condenser 130 may be connected by a water circulation pipe 111 for the condenser. The water circulation pipe 111 for the condenser supplies water from the hot water storage tank 110 to the condenser 130 and then returns it to the hot water storage tank 110.

The circulation pump 116 for the condenser may be installed in the water circulation pipe 111 for the condenser to circulate water. The circulation pump 116 for the condenser may be disposed between the outlet end of the hot water storage tank 110 and the inlet end of the condenser 130 . The condenser circulation pump 116 is driven and controlled by the controller 180 .

The water outlet temperature sensor 117 may be installed in the water circulation pipe 111 for the condenser to measure the temperature of the water discharged from the condenser 130 to the hot water storage tank 110 . The outlet temperature sensor 117 may be disposed between the outlet end of the condenser 130 and the inlet end of the hot water storage tank 110 . The water outlet temperature sensor 117 provides the measured temperature information to the controller 180 .

The flow control valve 118 for the condenser may be installed in the water circulation pipe 111 for the condenser to adjust the circulation amount of water circulating between the hot water storage tank 110 and the condenser 130 . The flow control valve 118 for the condenser may be disposed between the outlet end of the condenser circulation pump 116 and the inlet end of the condenser 130 . The flow control valve 118 for the condenser may be made of an electronic proportional control valve. The electronic proportional control valve is configured to proportionally control the flow rate of water passing through the internal passage according to an electrical signal input from the controller 180.

The controller 180 controls the flow control valve 118 for the condenser based on the information measured by the water outlet temperature sensor 117 to adjust the temperature of the water discharged from the hot water storage tank 110 to a set range. . The controller 180 may compare the temperature value measured by the water outlet temperature sensor 117 with a target temperature value and control the condenser flow control valve 118 to adjust the water circulation amount proportional to the difference value. The controller 180 produces hot water of 70 to 95° C. from the hot water storage tank and taps the hot water so that the hot water can be used in various places such as a bathhouse, sauna, or accommodation.

The compressor 120 compresses the carbon dioxide refrigerant from a low-temperature low-pressure gas to a high-temperature high-pressure gas. The compressor 120 compresses the refrigerant discharged from the evaporator 150 and supplies it to the condenser 130 . The compressor 120 is driven and controlled by the controller 180 .

The condenser 130 heats the water supplied from the hot water storage tank 110 by exchanging heat with the refrigerant supplied from the compressor 120, and then discharges the water to the hot water storage tank 110. That is, the condenser 130 generates condensation heat in the process of condensing the refrigerant from a gaseous state to a supercritical state, and heats the water supplied from the hot water storage tank 110 with the condensation heat, so that the heated water is stored in the hot water storage tank 110. ) to be stored. The condenser 130 discharges the condensed refrigerant to the expansion valve 140 .

For example, the condenser 130 may be configured as a plate heat exchanger. In this case, the condenser 130 may be configured such that a plurality of flat plates are arranged at regular intervals to have passages and the refrigerant and water pass through the passages skipping one by one. As another example, the condenser 130 may be configured as a heat exchanger obtained by processing a double tube in which a refrigerant flow path and a water flow path are coaxially formed into a corrugate shape, and thus the condenser 130 is not limited to the illustrated one.

The expansion valve 140 receives the refrigerant condensed through the condenser 130 and depressurizes it. The expansion valve 140 supplies the reduced-pressure refrigerant to the evaporator 150 . The expansion valve 140 may be composed of an electronic expansion valve and driven and controlled by the controller 180 .

The evaporator 150 receives the refrigerant reduced through the expansion valve 140, evaporates it, and then discharges the refrigerant to the compressor 120. The evaporator 150 heat-exchanges the refrigerant therein with water in the process of receiving and discharging water from the water supply source 160 for the evaporator. Similar to the condenser 130, the evaporator 150 may be formed of a plate heat exchanger or a corrugated heat exchanger.

The evaporator 150 is sequentially connected to the compressor 120, the condenser 130, and the expansion valve 140 through the refrigerant circulation pipe 101. The refrigerant goes through the compressor 120, the condenser 130, the expansion valve 140, and the evaporator 150 in order to repeat the supercritical cycle in which the state changes, so that hot water can be produced by the supercritical condensation heat of the condenser 130. do.

The water supply source 160 for the evaporator supplies water to the evaporator 150 so that the refrigerant in the evaporator 150 exchanges heat with water heated by renewable energy or waste heat. Here, renewable energy may be solar heat, geothermal heat, and the like. The waste heat may be waste water heat, waste gas heat, steam condensate, and the like.

The water supply source 160 for the evaporator may increase the ambient temperature of the evaporator 150 by supplying heated water to the evaporator 150 . The water source 160 for the evaporator makes it possible to increase the evaporation efficiency of the evaporator 150 by generating a difference between the refrigerant temperature in the evaporator 150 and the ambient temperature of the evaporator 150 so that the evaporation temperature can be changed to a set value. . Therefore, the heat pump 100 of the present embodiment can sufficiently secure evaporation efficiency even in winter when the ambient temperature drops below zero, and thus can produce hot water without stopping operation.

The water supply source 160 for the evaporator may include a water supply tank 161, a water circulation pipe 162 for the evaporator, a circulation pump 163 for the evaporator, and a flow control valve 164 for the evaporator. The water supply tank 161 stores water heated by renewable energy or waste heat. Water in the water supply tank 161 may be heated by heat exchange with renewable energy or waste heat. The water circulation pipe 162 for the evaporator supplies water from the water supply tank 161 to the evaporator 150 and then returns it to the water supply tank 161 .

The evaporator circulation pump 163 is installed in the evaporator water circulation pipe 162 to circulate water. The circulation pump 163 for the evaporator may be disposed between the outlet end of the water supply tank 161 and the inlet end of the evaporator 150 . The circulating pump 163 for the evaporator is driven and controlled by the controller 180 .

The flow control valve 164 for the evaporator is installed in the water circulation pipe 162 for the evaporator to control the circulation amount of water circulating between the water supply tank 161 and the evaporator 150 . The flow control valve 164 for the evaporator may be disposed between the outlet end of the evaporator circulation pump 162 and the inlet end of the evaporator 150 . The flow control valve 164 for the evaporator may be made of an electronic proportional control valve.

An evaporator intake temperature sensor 165 may be installed in the water circulation pipe 162 for the evaporator to measure the temperature of water supplied to the evaporator 150 from the water supply tank 161 . The evaporator inlet temperature sensor 165 may be disposed between the evaporator circulation pump 1163 and the inlet end of the evaporator 150 . The evaporator intake temperature sensor 165 provides the measured temperature information to the controller 180 .

The controller 180 may control the flow control valve 164 for the evaporator to compare the temperature value measured from the evaporator inlet temperature sensor 165 with the target temperature value and adjust the water circulation amount proportional to the difference value. Therefore, even if the evaporator intake temperature is high, it can be supplied to the evaporator 150 after adjusting only the required amount of heat.

The evaporation temperature sensor 170 measures the evaporation temperature of the refrigerant supplied from the expansion valve 140 to the evaporator 150 . The evaporation temperature sensor 170 is disposed between the expansion valve 140 and the evaporator 150 . The evaporation temperature sensor 170 provides the measured temperature information to the controller 180.

Based on the information measured by the evaporation temperature sensor 170, the controller 180 controls the water source 160 for the evaporator to adjust the amount of water supplied to the evaporator 150, thereby changing the evaporation temperature of the refrigerant to a set value. do. Here, the controller 180 may change the evaporation temperature of the refrigerant to a set value by controlling the water circulation amount by controlling the flow control valve 164 for the evaporator based on the information measured by the evaporation temperature sensor 170. Therefore, only the required amount of heat is used from the water supply source 160 for the evaporator, thereby increasing the evaporation efficiency.

In addition, when the temperature of the water flowing into the condenser 130 increases, the discharge temperature of the refrigerant discharged from the compressor 120 increases. The refrigerant discharge temperature can be lowered by controlling the flow control valve 164 for the evaporator in (160) to lower the evaporation temperature of the refrigerant.

In this case, the discharge temperature sensor 121 may measure the discharge temperature of the refrigerant discharged from the compressor 120 . The discharge temperature sensor 121 may be disposed between the compressor 120 and the condenser 130 . The discharge temperature sensor 121 provides the measured temperature information to the controller 180 . The controller 180 may change the evaporation temperature of the refrigerant based on information measured by the discharge temperature sensor 121 to maintain the discharge temperature below a set value. The controller 180 receives the temperature measured from the condenser inlet temperature sensor 131 together with the temperature information measured from the discharge temperature sensor 121 and can change the evaporation temperature of the refrigerant to maintain the discharge temperature below a set value. .

As such, the heat pump 100 of the present embodiment can be optimized by changing the evaporation temperature set value according to the inlet temperature of the condenser 130 and maintaining the discharge temperature of the refrigerant below the set value, so that the inlet temperature of the condenser 130 is Even if it is high, it can operate stably up to about 67 degreeC, for example.

As an additional aspect, both ends of the refrigerant bypass pipe 102 may be connected to the refrigerant outlet of the compressor 120 and the refrigerant inlet of the evaporator 150 . The expansion tank 103 may be installed in the refrigerant bypass pipe 102. The expansion tank 103 introduces and discharges the refrigerant through the refrigerant bypass pipe 102 .

The first electromagnetic valve 104 may be disposed at the refrigerant inlet end of the expansion tank 103 and installed in the refrigerant bypass pipe 102 . The first electromagnetic valve 104 opens and closes the internal flow path connected to the refrigerant bypass pipe 102 . The first electromagnetic valve 104 operates to open to allow refrigerant to flow from the compressor 120 to the expansion tank 103, and to close to block refrigerant from flowing into the expansion tank from the compressor 120. The first electromagnetic valve 104 may be formed of a solenoid valve or the like.

The first solenoid valve 104 is driven and controlled by the controller 180 . The first electromagnetic valve 104 may be a normally closed (NC) type. The first electromagnetic valve 104 may open according to an ON signal of the controller 180 and close according to an OFF signal of the controller 180 .

The second electromagnetic valve 105 may be disposed at the refrigerant outlet side of the expansion tank 103 and installed in the refrigerant bypass pipe 102 . The second electromagnetic valve 105 opens and closes the internal flow path connected to the refrigerant bypass pipe 102 . The second solenoid valve 105 may open to allow refrigerant to be discharged from the expansion tank 103 and close to block refrigerant from the expansion tank 103 . The second solenoid valve 105 may have the same configuration as the first solenoid valve 104 .

When the discharge pressure of the refrigerant discharged from the compressor 120 exceeds a set value, the controller 180 opens the first solenoid valve 104 and closes the second solenoid valve 105 to supply the refrigerant to the expansion tank 103. bypass it When the discharge pressure of the refrigerant discharged from the compressor 120 is less than a set value, the controller 180 closes the first solenoid valve 104 and opens the second solenoid valve 105 to increase the pressure in the expansion tank 103. lower it Here, the discharge pressure of the refrigerant may be measured by a pressure sensor installed in the compressor 120 and provided to the controller 180 .

The controller 180 repeats the above process to absorb excessive pressure of the refrigerant by the expansion tank 103 and maintain a constant pressure, thereby allowing the heat pump 100 to operate stably.

As such, according to the hybrid carbon dioxide heat pump 100 of the present embodiment, it is possible to increase the evaporation efficiency by supplying water heated by renewable energy or waste heat to the evaporator 150, as well as to change the evaporation temperature to the set value. Energy efficiency can be increased by using only heat.

In addition, according to the hybrid carbon dioxide heat pump 100 of this embodiment, the evaporation temperature set value can be changed according to the inlet temperature of the condenser 130 to optimize the discharge temperature of the refrigerant by maintaining it below the set value, so that the condenser 130 It can operate stably even when the water temperature is high. In addition, according to the hybrid carbon dioxide heat pump 100 of this embodiment, it is possible to operate stably by preventing overpressure of the refrigerant that may occur during operation.

The present invention has been described with reference to an embodiment shown in the accompanying drawings, but this is only exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. You will be able to. Therefore, the true protection scope of the present invention should be defined only by the appended claims.

100..Hybrid carbon dioxide heat pump
101.. Refrigerant circulation pipe 102.. Refrigerant bypass pipe
103.. expansion tank 104.. first solenoid valve
105.. Second solenoid valve 110.. Hot water storage tank
111.. Water circulation pipe for condenser 112.. Make-up water supply pipe
113. Hot water discharge pipe 116.. Circulation pump for condenser
117. Outlet water temperature sensor 118. Flow control valve for condenser
120.. Compressor 121.. Discharge temperature sensor
130.. condenser 131.. condenser inlet temperature sensor
140.. expansion valve 150.. evaporator
160.. water source for evaporator 161.. water tank
162.. water circulation pipe for evaporator 163.. circulation pump for evaporator
164.. Flow control valve for evaporator 165.. Evaporator inlet temperature sensor
170.. Evaporation temperature sensor 180.. Controller

Claims (5)

hot water storage tank;
A compressor for compressing carbon dioxide refrigerant from a low-temperature, low-pressure gas to a high-temperature, high-pressure gas;
a condenser that heats the water supplied from the hot water storage tank by exchanging heat with the refrigerant supplied from the compressor, and discharges the water to the hot water storage tank;
an expansion valve for receiving the refrigerant condensed through the condenser and reducing the pressure;
an evaporator that receives the refrigerant reduced through the expansion valve, evaporates it, and discharges the refrigerant to the compressor;
a water supply source for the evaporator supplying water to the evaporator so that the refrigerant in the evaporator exchanges heat with water heated by renewable energy or waste heat;
an evaporation temperature sensor for measuring an evaporation temperature of the refrigerant supplied from the expansion valve to the evaporator; and
Based on the information measured from the evaporation temperature sensor, a controller that changes the evaporation temperature of the refrigerant to a set value by controlling the water supply for the evaporator to adjust the amount of water supplied to the evaporator; includes,
Further comprising a discharge temperature sensor for measuring the discharge temperature of the refrigerant discharged from the compressor;
Based on the information measured by the discharge temperature sensor, the controller lowers the evaporation temperature by controlling the water source for the evaporator when the discharge temperature of the refrigerant becomes higher than the reference temperature as the temperature of the water flowing into the condenser increases. maintaining the discharge temperature below the set point;
A refrigerant bypass pipe having both ends connected to a refrigerant outlet end of the compressor and a refrigerant inlet end of the evaporator;
An expansion tank installed in the refrigerant bypass pipe;
A first electromagnetic valve disposed at the refrigerant inlet end of the expansion tank, installed in the refrigerant bypass pipe, and allowing refrigerant to flow from the compressor into the expansion tank when opened; and
a second solenoid valve disposed at the refrigerant outlet side of the expansion tank, installed in the refrigerant bypass pipe, and allowing discharge of the refrigerant from the expansion tank toward the refrigerant inlet end of the evaporator during an open operation;
When the discharge pressure of the refrigerant discharged from the compressor exceeds a set value, the controller opens the first electromagnetic valve and closes the second electromagnetic valve to bypass the refrigerant to the expansion tank, and the refrigerant discharged from the compressor The hybrid carbon dioxide heat pump, characterized in that when the discharge pressure of is lower than the set value, the first electromagnetic valve is closed and the second electromagnetic valve is opened to lower the pressure of the expansion tank.
delete According to claim 1,
The water supply source for the evaporator includes a water supply tank for storing water heated by renewable energy or waste heat;
A water circulation pipe for an evaporator supplying water from the water supply tank to the evaporator and then returning it to the water supply tank;
A circulation pump for the evaporator installed in the water circulation pipe for the evaporator to circulate water, and
and a flow control valve for the evaporator installed in the water circulation pipe for the evaporator to control the circulation amount of water circulating between the water supply tank and the evaporator;
The hybrid carbon dioxide heat pump, characterized in that the controller changes the evaporation temperature of the refrigerant to a set value by controlling the water circulation amount by controlling the flow control valve for the evaporator based on the information measured from the evaporation temperature sensor.
According to claim 1,
A water circulation pipe for a condenser supplying water from the hot water storage tank to the condenser and then returning it to the hot water storage tank;
A circulation pump for the condenser installed in the water circulation pipe for the condenser to circulate water;
An outlet temperature sensor installed in the water circulation pipe for the condenser to measure the temperature of the water discharged from the condenser to the hot water storage tank, and
A flow control valve for the condenser installed in the water circulation pipe for the condenser to adjust the amount of circulation of water circulating between the hot water storage tank and the condenser;
The controller controls the flow control valve for the condenser based on the information measured from the water outlet temperature sensor to adjust the temperature of the water tapped from the hot water storage tank to the outside within a set range. Hybrid carbon dioxide heat pump.
delete

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