CO2 unit and CO2 heat pump system

Abstract

The invention relates to the technical field of air conditioners, in particular to a CO2 unit and a CO2 heat pump system. The CO2 heat pump unit aims at solving the problems that the exhaust temperature of a compressor of the CO2 heat pump unit is too high under the low environment temperature, and the heat pump performance is reduced when the return water temperature of an air cooler is high. In order to achieve the purpose, the CO2 unit comprises a compressor, an air cooler, a throttling element, an evaporator and an air preheater. Wherein the evaporator is an air cooling evaporator, the air preheater is arranged on the upstream side of the air inlet direction of the evaporator, a first port of the air preheater is communicated with a heat supply and water return connector of the CO2 unit, and a second port of the air preheater is communicated with a first liquid port of the air cooler. According to the CO2 unit, the problems that the exhaust temperature of the compressor of the CO2 heat pump unit is too high at the low environment temperature and the heat pump performance is reduced when the return water temperature of the air cooler is high can be solved at the same time, the operation stability and the heating capacity in the low-temperature environment are improved, and meanwhile the heating performance in the heating scene is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the air conditioning technical field, specifically to a CO2 unit and a CO2 heat pump system. BACKGROUND

[0002] CO2 (carbon dioxide) as a natural refrigerant, with its low cost, has zero ODP value (ozone depletion potential), low GWP value (global warming potential), non-toxic and non-flammable, high heat transfer coefficient and other characteristics, which is very suitable for use as an air conditioning alternative refrigerant. Among them, the high heat transfer coefficient of CO2 determines that it is very suitable for the application scene of heating operation.

[0003] In practical application, the CO2 heat pump unit based on heating and hot water demand faces two key technical problems: first, at low ambient temperature, the evaporation temperature and evaporation pressure of the refrigerant in the evaporator are low, so that the compression ratio of the compressor is large, and the exhaust temperature of the compressor is high. If the exhaust temperature is too high, the compressor will not run normally. In addition, the low evaporation temperature will also cause the specific volume of the compressor to be large (i.e. the density decreases), and the refrigerant circulation mass flow decreases, resulting in small system heating capacity and unable to meet user demand. The second aspect is that in the heating scene, the temperature difference between the inlet and outlet water temperature of the heating terminal is small, usually the inlet water temperature is about 40℃, and the outlet water temperature is about 35℃. At this time, the return water temperature of the air cooler (i.e. the outlet water temperature of the heating terminal) is relatively high, so the refrigerant temperature at the outlet of the air cooler is also high, which means that the refrigerant dryness at the inlet of the evaporator is large, the heat pump system absorbs less heat from the environment, the heating capacity of the air cooler decreases, and the advantage of large temperature span of CO2 refrigerant cannot be fully utilized, and the heat pump performance decreases.

[0004] To solve the above two technical problems, the utility model patent with publication number CN205807620U discloses a circulating water heating system based on carbon dioxide heat pump. The patent adds a second heat exchanger to heat the low-temperature carbon dioxide in the carbon dioxide heat pump system using the waste heat of the circulating return water, so as to improve the evaporation efficiency of carbon dioxide, thereby ensuring the stable compression efficiency of the compressor, and at the same time, the temperature of the circulating return water is reduced, the heat energy is fully utilized, the continuous, stable and efficient heat exchange in the first heat exchanger is ensured, the entire heating system is more energy-saving and stable, and has high heating efficiency.

[0005] However, the applicant discovered through actual testing that the technical solution of the aforementioned patent cannot simultaneously solve the two technical problems mentioned above, for the following reasons: In this technical solution, the cold source for cooling the circulating return water is the cooling capacity of the refrigerant between the evaporator outlet and the compressor suction port. Although the temperature of the refrigerant is low in this state, it is in a saturated gaseous state with a small heat capacity. After exchanging heat with the circulating return water, its temperature will rise significantly, resulting in excessively high refrigerant temperature entering the compressor, and further increasing the compressor discharge temperature. In other words, while this solution alleviates the problem of reduced system performance due to high circulating return water temperature, it exacerbates another problem due to the further increase in compressor discharge temperature.

[0006] Accordingly, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0007] To address at least one of the aforementioned problems in the prior art, namely, to resolve the issue of reduced heat pump performance in CO2 heat pump units when the compressor exhaust temperature is too high at low ambient temperatures and the return water temperature of the air cooler is too high, this application provides a CO2 unit comprising:

[0008] compressor;

[0009] An air cooler includes a first refrigerant port, a second refrigerant port, a first liquid port, and a second liquid port. A first heat exchange channel is formed between the first refrigerant port and the second refrigerant port, and a second heat exchange channel is formed between the first liquid port and the second liquid port. Heat exchange can occur between the first heat exchange channel and the second heat exchange channel. The first refrigerant port is connected to the exhaust port of the compressor, and the second liquid port is connected to the heating water outlet of the CO2 unit.

[0010] A throttling element, wherein the first port of the throttling element is connected to the second refrigerant port;

[0011] An evaporator, wherein the evaporator is an air-cooled evaporator, and the first port of the evaporator is connected to the second port of the throttling element, and the second port of the evaporator is connected to the suction port of the compressor;

[0012] An air preheater is provided, located upstream of the evaporator in the air inlet direction. The first port of the air preheater is connected to the heating return water interface of the CO2 unit, and the second port is connected to the first liquid port.

[0013] The CO2 unit of the present application can solve the problems of high compressor discharge temperature and reduced heat pump performance of the CO2 heat pump unit under low ambient temperature by setting the air preheater on the upstream side of the evaporator inlet air direction, improve the operation stability and heating capacity under low temperature environment, and improve the heating performance under heating scene.

[0014] Specifically, the first port of the air preheater is in communication with the heating return water interface, and the second port is in communication with the first liquid port, which can realize the waste heat utilization of the heating return water, utilize the heat exchange between the low-temperature cold air and the air preheater, reduce the return water temperature entering the air cooler, thereby fully utilizing the large temperature glide characteristics of the CO2 refrigerant, and improving the heating performance of the CO2 unit. Moreover, the temperature of the low-temperature cold air is increased after heat exchange with the air preheater, which can increase the temperature of the air blown into the evaporator, thereby increasing the evaporation temperature and evaporation pressure, reducing the compression ratio and discharge temperature of the compressor, so that the system can still stably heat under low ambient temperature. At the same time, the increase of the evaporation temperature can increase the refrigerant circulation mass flow rate, and the heating capacity under low ambient temperature can be increased.

[0015] Compared with the utility model patent in the background art, the cold source for pre-cooling the heating return water in the present application is low-temperature cold air, not refrigerant, so it will not cause the increase of the compressor return air temperature, and will not cause the further increase of the discharge temperature. In addition, the cold air is preheated and exchanged with the evaporator, which can increase the evaporation temperature of the refrigerant instead of the temperature increase of the refrigerant itself, and the increase of the evaporation temperature can reduce the compression ratio of the compressor, and at this time, the discharge temperature of the compressor can also be reduced, thereby solving the two technical problems in the background art.

[0016] In the preferred technical solutions of the above-mentioned CO2 unit, the air preheater and the evaporator are independently arranged.

[0017] The air preheater and the evaporator are different pipe sections of the same heat exchanger.

[0018] In the preferred technical solutions of the above-mentioned CO2 unit, the air preheater and the evaporator are independently arranged.

[0019] In the preferred technical solutions of the above-mentioned CO2 unit, the CO2 unit further comprises a first electrically controlled three-way valve and a second electrically controlled three-way valve, the first interface of the first electrically controlled three-way valve is in communication with the heating return water interface, the second interface of the first electrically controlled three-way valve is in communication with the first port of the air preheater, the first interface of the second electrically controlled three-way valve is in communication with the second liquid port, the second interface of the second electrically controlled three-way valve is in communication with the heating outlet water interface, and the third port of the second electrically controlled three-way valve is in communication with the third port of the first electrically controlled three-way valve.

[0020] By setting the first electrically controlled three-way valve and the second electrically controlled three-way valve, the flow direction of the heat supply return water and the flow of each flow direction can be adjusted by using the two, so as to realize accurate temperature adjustment of the first liquid port of the air cooler and the heat supply outlet.

[0021] In the preferred technical solution of the CO2 unit, the CO2 unit further comprises a first pump body, a liquid return port of the first pump body being in communication with the second liquid port, and a liquid discharge port of the first pump body being in communication with the heat supply outlet.

[0022] In the preferred technical solution of the CO2 unit, the CO2 unit further comprises a four-way valve, four interfaces of the four-way valve being in communication with the exhaust port of the compressor, the first refrigerant interface, the second port of the evaporator, and the suction port of the compressor, respectively.

[0023] The application also provides a CO2 heat pump system, comprising:

[0024] a heat cycle assembly;

[0025] The CO2 unit in any of the above technical solutions, the heat cycle assembly being in communication with the heat supply outlet and the heat supply return interface, respectively.

[0026] The CO2 heat pump system of the application can solve the problems of high compressor exhaust temperature and reduced heat pump performance when the return water temperature of the air cooler is high, improve the operation stability and heating capacity in a low-temperature environment, and improve the heating performance in a heating scenario.

[0027] In the preferred technical solution of the CO2 heat pump system, the heat cycle assembly comprises a heat supply water tank and a heating pipeline, a heat exchange pipe is arranged in the heat supply water tank, a first end of the heat exchange pipe and a first end of the heating pipeline are in communication with the heat supply outlet, and a second end of the heat exchange pipe and a second end of the heating pipeline are in communication with the heat supply return interface.

[0028] The above arrangement can simultaneously realize two combined supplies of heat supply water and heating of the CO2 heat pump system.

[0029] In the preferred technical solution of the CO2 heat pump system, the heat cycle assembly further comprises a buffer water tank and a third electrically controlled three-way valve, the buffer water tank has a first inlet, a second inlet, and a first outlet, the first inlet is in communication with the heat supply outlet, the first outlet is in communication with the first end of the heating pipeline, a first interface of the third electrically controlled three-way valve is in communication with the second end of the heating pipeline, a second interface of the third electrically controlled three-way valve is in communication with the heat supply return interface, and a third interface of the third electrically controlled three-way valve is in communication with the second inlet of the buffer water tank.

[0030] By setting the third electrically controlled three-way valve and the buffer water tank, the water temperature entering the heating pipeline can be adjusted by using the buffer water tank, so that more accurate and stable control is realized.

[0031] In the preferred technical solution of the CO2 heat pump system, the heat circulation assembly further comprises a fourth electrically controlled three-way valve, a first interface of the fourth electrically controlled three-way valve is in communication with the second end of the heat exchange pipe, a second interface of the fourth electrically controlled three-way valve is in communication with the heat supply return water interface, and a third interface of the fourth electrically controlled three-way valve is in communication with the second inlet of the buffer water tank; and / or

[0032] The heat circulation assembly further comprises a second pump body, and a liquid discharge port of the second pump body is in communication with the second inlet of the buffer water tank.

[0033] By setting the fourth electrically controlled three-way valve, the water outlet of the heat exchange pipe enters the buffer water tank to adjust the water temperature in the buffer water tank, so that cascade utilization of heat is realized, and the system energy efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] The present application will be described below with reference to the accompanying drawings. In the drawings:

[0035] Figure 1 The system diagram of the CO2 heat pump system of the present application.

[0036] List of reference signs

[0037] 10, CO2 unit; 11, compressor; 12, air cooler; 13, throttling element; 14, evaporator; 141, fan; 15, air preheater; 161, first electrically controlled three-way valve; 162, second electrically controlled three-way valve; 17, first pump body; 18, four-way valve; 191, heat supply return water interface; 192, heat supply water outlet interface;

[0038] 20, heat circulation assembly; 21, heat supply water tank; 22, heating pipeline; 23, heat exchange pipe; 24, buffer water tank; 251, third electrically controlled three-way valve; 252, fourth electrically controlled three-way valve; 26, second pump body; 271, first on-off valve; 272, second on-off valve. DETAILED DESCRIPTION

[0039] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application.

[0040] It should be noted that in the description of this application, the terms "upper," "lower," "left," "right," "inner," and "outer," which indicate directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These terms are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0042] First refer to Figure 1 This paper provides a brief introduction to the CO2 unit of this application. Figure 1 In the diagram, the refrigerant flow path is drawn with a solid line, while the heat transfer medium flow path is drawn with a dotted dashed line.

[0043] like Figure 1 As shown, to address the issue of reduced heat pump performance in CO2 heat pump units when the compressor discharge temperature is too high under low ambient temperatures and the return water temperature of the air cooler is too high, the CO2 unit 10 of this application includes a compressor 11, an air cooler 12, a throttling element 13, an evaporator 14, and an air preheater 15. The air cooler 12 includes a first refrigerant port ( Figure 1 Middle left lower port), second refrigerant port ( Figure 1 Middle left upper port), first liquid port ( Figure 1 Middle right upper port) and second liquid port ( Figure 1 The first refrigerant port and the second refrigerant port form a first heat exchange channel, and the first liquid port and the second liquid port form a second heat exchange channel, which can exchange heat. The first refrigerant port is connected to the exhaust port of the compressor 11, and the second liquid port is connected to the heating water outlet 192 of the CO2 unit 10. The first port of the throttling element 13 (… Figure 1 The right-hand port of the evaporator 14 is connected to the second refrigerant port. The evaporator 14 is an air-cooled evaporator 14, and the first port of the evaporator 14 ( Figure 1 The upper port) and the second port of the throttling element 13 ( Figure 1 The left port of the middle section is connected to the second port of the evaporator 14. Figure 1The middle lower side port is in communication with the suction port of the compressor 11. The throttling element 13 can be an electronic expansion valve or a capillary tube.

[0044] The air preheater 15 is arranged on the upstream side of the air inlet direction of the evaporator 14. The first port (the middle upper side port) of the air preheater 15 is in communication with the heat supply return water interface 191 of the CO2 unit 10, and the second port (the middle lower side port) is in communication with the first liquid port. Figure 1 Figure 1 The middle lower side port is in communication with the suction port of the compressor 11. The throttling element 13 can be an electronic expansion valve or a capillary tube.

[0045] The heat supply outlet water interface 192 and the heat supply return water interface 191 in the present application refer to the interfaces of the CO2 unit 10 and the heat circulation assembly 20. In actual products, the heat supply outlet water interface 192 and the heat supply return water interface 191 are arranged on the shell of the equipment. By connecting the total inlet water pipe and the total outlet water pipe in the pipeline of the heat circulation assembly 20 to the heat supply outlet water interface 192 and the heat supply return water interface 191, the entire system is built.

[0046] In the above arrangement, when the CO2 unit 10 is running, on the one hand, the CO2 refrigerant discharged by the compressor 11 passes through the air cooler 12, the throttling element 13 and the evaporator 14 in turn to return to the compressor 11, forming a refrigerant circulation. The CO2 refrigerant releases heat when passing through the air cooler 12 and absorbs heat when passing through the evaporator 14. On the other hand, the heat-conducting medium (such as water, ethylene glycol or a mixture of the two) in the heat circulation assembly 20 exchanges heat with the refrigerant in the air cooler 12 to increase the temperature. The heat-exchanged heat-conducting medium is discharged from the CO2 unit 10 through the heat supply outlet water interface 192 and enters the heat circulation assembly 20 to provide heat (such as providing domestic hot water, heating water, etc.) for users, and the temperature decreases. The heat-conducting medium with reduced temperature enters the CO2 unit 10 through the heat supply return water interface 191, and exchanges heat with outdoor air when passing through the air preheater 15, and the temperature further decreases. The heat-conducting medium with further reduced temperature enters the air cooler 12 to participate in heat exchange again. The above-mentioned cold air with increased temperature after exchanging heat with the air preheater 15 continues to exchange heat with the evaporator 14.

[0047] The CO2 unit 10 of the present application can solve the problems of high exhaust temperature of the compressor 11 and low heat pump performance of the air cooler 12 when the return water temperature is high, by arranging the air preheater 15 on the upstream side of the air inlet direction of the evaporator 14. The running stability and heating capacity in low temperature environment are improved, and the heating performance in heating scenarios is improved.

[0048] ​Specifically, the first port of the air preheater 15 is in communication with the heating return water interface 191, and the second port is in communication with the first liquid port, so that the waste heat of the heating return water can be utilized, the low-temperature cold air is used to exchange heat with the air preheater 15, the temperature of the return water entering the air cooler 12 is reduced, the large temperature glide characteristics of the CO2 refrigerant are fully utilized, and the heating performance of the CO2 unit 10 is improved. Moreover, the temperature of the low-temperature cold air is increased after heat exchange with the air preheater 15, so that the temperature of the air blown into the evaporator 14 can be increased, the evaporation temperature and the evaporation pressure are increased, the compression ratio and the exhaust temperature of the compressor 11 are reduced, and the system can still stably heat at a low ambient temperature. At the same time, the increase of the evaporation temperature can increase the refrigerant circulation mass flow rate, and the heating capacity at a low ambient temperature can be increased.

[0049] Compared with the utility model patent in the background art, the cold source for pre-cooling the heating return water in the present application is low-temperature cold air, not refrigerant, so that the return air temperature of the compressor 11 is not increased, and the exhaust temperature is not further increased. In addition, the cold air is preheated and exchanged with the evaporator 14, so that the evaporation temperature of the refrigerant is increased instead of the temperature of the refrigerant itself, and the compression ratio of the compressor 11 is reduced, so that the exhaust temperature of the compressor 11 is also reduced, thereby solving the two technical problems in the background art.

[0050] Further reference will be made below Figure 1 to introduce a possible embodiment of the CO2 unit 10 of the present application.

[0051] As Figure 1 shown, in a specific embodiment, the CO2 unit 10 includes a compressor 11, a four-way valve 18, an air cooler 12, a throttling element 13, an evaporator 14, an air preheater 15, a first pump body 17, a first electrically-controlled three-way valve 161, and a second electrically-controlled three-way valve 162.

[0052] The four-way valve 18 has four interfaces a, b, c, and d. The air cooler 12 is a liquid-cooled heat exchanger, which includes a first refrigerant port, a second refrigerant port, a first liquid port, and a second liquid port. The first refrigerant port and the second refrigerant port form a first heat exchange channel therebetween, the first liquid port and the second liquid port form a second heat exchange channel therebetween, and the first heat exchange channel and the second heat exchange channel can exchange heat therebetween. The evaporator 14 is a wind-cooled evaporator 14, such as a fin heat exchanger, which is provided with a fan 141 arranged at an air outlet side of the evaporator 14.

[0053] In this configuration, the discharge port of compressor 11 is connected to interface a of four-way valve 18; interface b of four-way valve 18 is connected to the first refrigerant port of air cooler 12; the second refrigerant port of air cooler 12 is connected to the first port of throttling element 13; the second port of throttling element 13 is connected to the first port of evaporator 14; the second port of evaporator 14 is connected to interface c of four-way valve 18; and interface d of four-way valve 18 is connected to the suction port of compressor 11. Thus, a refrigerant cycle is formed between compressor 11, four-way valve 18, air cooler 12, throttling element 13, and evaporator 14. The working principle of this refrigerant cycle is common knowledge in the art and will not be elaborated further in this application.

[0054] The air preheater 15 is an air-cooled heat exchanger, which is set independently of the evaporator 14 and is arranged side by side on the air inlet side of the evaporator 14. When the fan 141 is started, the outdoor air passes through the air preheater 15 and the evaporator 14 in sequence, and exchanges heat with the air preheater 15 and the evaporator 14 in turn.

[0055] The first port of the first electrically controlled three-way valve 161 ( Figure 1 The right-side interface is connected to the heating return water interface 191, and the second interface of the first electrically controlled three-way valve 161 ( Figure 1 The left-side interface is connected to the first port of the air preheater 15. The first interface of the second electrically controlled three-way valve 162 ( Figure 1 The left-side interface is connected to the second liquid port of the air cooler 12, and the second interface of the second electrically controlled three-way valve 162 is connected to the second liquid port of the air cooler 12. Figure 1 The right-side interface is connected to the heating water outlet interface 192, and the third port of the second electrically controlled three-way valve 162 ( Figure 1 The upper interface) and the third port of the first electrically controlled three-way valve 161 ( Figure 1 (Lower interface) connected. The first electrically controlled three-way valve 161 and the second electrically controlled three-way valve 162 can be either solenoid-controlled or electrically controlled valves. Both valves can achieve flow diversion control. Taking the first electrically controlled three-way valve 161 as an example, by controlling the valve core of the first electrically controlled three-way valve 161, its first interface can be connected to the second interface independently, its first interface can be connected to the third interface independently, or its first interface can be connected to both the second and third interfaces simultaneously. The outlet flow of the second and third interfaces can be adjusted by changing the position of the valve core.

[0056] The first pump body 17 is a water pump, and the return port of the water pump is connected to the second liquid port. The discharge port of the first pump body 17 is connected to the first interface of the second electrically controlled three-way valve 162.

[0057] The four-way valve 18 is provided to realize multi-mode operation of the CO2 unit 10. The air preheater 15 and the evaporator 14 are independently arranged to reduce the design and installation difficulty. The air preheater 15 and the evaporator 14 are arranged side by side to improve the heat exchange effect of the air flow. The first electrically-controlled three-way valve 161 and the second electrically-controlled three-way valve 162 are provided to adjust the flow direction of the heating return water and the flow of each flow direction, and to realize accurate temperature adjustment of the first liquid port of the air cooler 12 and the heating outlet 192.

[0058] The CO2 heat pump system of the present application will be described below. Figure 1 The CO2 heat pump system of the present application will be described below.

[0059] As shown in Figure 1 , the CO2 heat pump system of the present application comprises a heat cycle assembly 20 and the CO2 unit 10 in the above embodiment, wherein the heat cycle assembly 20 is in communication with the heating outlet 192 and the heating return 191 respectively.

[0060] In a specific embodiment, the heat cycle assembly 20 comprises a heating water tank 21, a buffer water tank 24, a heating pipeline 22, a second pump body 26, a third electrically-controlled three-way valve 251 and a fourth electrically-controlled three-way valve 252.

[0061] The heating water tank 21 is used to provide domestic water for users, and a heat exchange pipe 23 is arranged therein. The first end (the upper end in Figure 1 ) of the heat exchange pipe 23 is in communication with the heating outlet 192 through the first on-off valve 271, and the second end (the lower end in Figure 1 ) of the heat exchange pipe 23 is connected to the first interface (the right interface in Figure 1 ) of the fourth electrically-controlled three-way valve 252, and the second interface (the left interface in Figure 1 ) of the fourth electrically-controlled three-way valve 252 is in communication with the heating return 191. The buffer water tank 24 has a first inlet, a second inlet and a first outlet. The first inlet (the left lower interface in Figure 1 ) is in communication with the heating outlet 192 through the second on-off valve 272, and the first outlet (the right interface in Figure 1 ) is in communication with the first end (the lower end in Figure 1 ) of the heating pipeline 22, and the second end (the upper end in Figure 1 ) of the heating pipeline 22 is in communication with the first interface (the right interface in Figure 1 ) of the third electrically-controlled three-way valve 251, and the second interface (the left interface in Figure 1The first on-off valve 271 and the second on-off valve 272 are both electromagnetic valves. The third electrically-controlled three-way valve 251 and the fourth electrically-controlled three-way valve 252 are similar to the first electrically-controlled three-way valve 161 and the second electrically-controlled three-way valve 162, and can achieve shunt control. Details are not described herein again.

[0062] Further, the third interface of the third electrically-controlled three-way valve 251 and the third interface of the fourth electrically-controlled three-way valve 252 are both in communication with the liquid return port of the second pump body 26. The liquid discharge port of the second pump body 26 is in communication with the second inlet of the buffer water tank 24.

[0063] The CO2 heat pump system of the present application can solve the problems of high exhaust temperature of the compressor 11 and low heat pump performance of the CO2 heat pump unit 10 at low ambient temperature, improve the operation stability and heating capacity at low temperature, and improve the heating performance in the heating scene. The heat cycle assembly 20 includes the heating water tank 21 and the heating pipeline 22, which can realize the combined supply of hot water and heating of the CO2 heat pump system. The third electrically-controlled three-way valve 251 and the buffer water tank 24 can be used to adjust the water temperature entering the heating pipeline 22, and realize more accurate and stable control. The fourth electrically-controlled three-way valve 252 can be used to adjust the water temperature in the buffer water tank 24 by using the outlet water of the heat exchange pipe 23, realize the cascade utilization of heat, and improve the system energy efficiency.

[0064] The working principle of the CO2 heat pump system of the present application will be described below. Figure 1 The working principle of the CO2 heat pump system of the present application will be described below.

[0065] As shown in Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure In a specific working process, the compressor 11, the fan 141, the first pump body 17 and the second pump body 26 are started and operated, the first on-off valve 271 and the second on-off valve 272 are opened, and the spools of the first electrically-controlled three-way valve 161, the second electrically-controlled three-way valve 162, the third electrically-controlled three-way valve 251 and the fourth electrically-controlled three-way valve 252 are all moved to the shunt position. At this time, the system performs two independent cycles of refrigerant circulation and medium circulation.

[0066] In the refrigerant circulation, the CO2 refrigerant discharged from the compressor 11 passes through the four-way valve 18, the gas cooler 12, the throttling element 13, the evaporator 14 and the four-way valve 18 in turn to return to the compressor 11. The CO2 refrigerant releases heat when passing through the gas cooler 12, and absorbs heat when passing through the evaporator 14.

[0067] In the medium circulation, the heat conducting medium exchanges heat with the refrigerant in the air cooler 12 and its temperature rises. The heat conducting medium after heat exchange enters the second electrically controlled three-way valve 162 under the pumping of the first pump body 17, and after mixing and temperature adjustment with the heat conducting medium flowing back from the first electrically controlled three-way valve 161, it is discharged from the CO2 unit 10 through the heat supply outlet water interface 192 and enters the heat circulation assembly 20. In the heat conducting medium entering the heat circulation assembly 20, part of it enters the heat supply water tank 21 through the first on-off valve 271 and exchanges heat with the water in the heat supply water tank 21, so that its temperature decreases. The heat conducting medium after temperature decrease flows to the fourth electrically controlled three-way valve 252, and after the fourth electrically controlled three-way valve 252, it is divided into two branches, one of which flows back to the CO2 unit 10 through the heat supply return water interface 191, and the other of which enters the buffer water tank 24 through the second pump body 26. In the heat conducting medium entering the heat circulation assembly 20, another part of it enters the buffer water tank 24 through the second on-off valve 272, and after mixing and temperature adjustment with the low-temperature heat conducting medium pumped into the buffer water tank 24 by the second pump body 26, it enters the heating pipeline 22 and exchanges heat with indoor air, so that its temperature decreases. The heat conducting medium after temperature decrease enters the third electrically controlled three-way valve 251, and after the third electrically controlled three-way valve 251, it is divided into two branches, one of which flows back to the CO2 unit 10 through the heat supply return water interface 191, and the other of which enters the buffer water tank 24 through the second pump body 26. The heat conducting medium entering the CO2 unit 10 through the heat supply return water interface 191 is also divided into two branches. The heat conducting medium in one of the branches flows to the second electrically controlled three-way valve 162, mixes and adjusts the temperature with the heat conducting medium from the air cooler 12, and is discharged from the CO2 unit 10. The heat conducting medium in the other branch enters the air preheater 15. Under the action of the fan 141, outdoor cold air first exchanges heat with the heat conducting medium in the air preheater 15. The heat conducting medium is thus further decreased in temperature, and the air after heat exchange is increased in temperature. The heat conducting medium further decreased in temperature enters the air cooler 12 to participate in heat exchange again. At this time, the temperature difference between the first liquid port and the second liquid port of the air cooler 12 is large, so that the large temperature span advantage of the CO2 refrigerant can be fully utilized to improve the system heating performance. The cold air increased in temperature after heat exchange with the air preheater 15 continues to exchange heat with the evaporator 14, which can increase the evaporation temperature and the evaporation pressure, reduce the compression ratio and the exhaust temperature of the compressor 11, so that the system can still stably heat at low ambient temperature. At the same time, the increase of the evaporation temperature can increase the mass flow of the refrigerant circulation, so that the heating capacity at low ambient temperature can be increased.

[0068] Of course, the above working principle only introduces one possible working process of the CO2 heat pump system, and those skilled in the art can adjust the working state of each component so that the present application is applicable to more specific application scenarios. For example, those skilled in the art can adjust the opening and closing of the first on-off valve 271 and the second on-off valve 272 so that the CO2 heat pump system only works in one of the hot water production and heating modes. For another example, those skilled in the art can also adjust the valve core positions of the first electrically controlled three-way valve 161, the second electrically controlled three-way valve 162, the third electrically controlled three-way valve 251, and the fourth electrically controlled three-way valve 252 to adjust the flow direction of the heat conducting medium, etc.

[0069] It should also be noted that the above embodiments of the CO2 unit 10 and the CO2 heat pump system are only used to illustrate the principles of the present application and are not intended to limit the scope of protection of the present application. Those skilled in the art can adjust the above arrangement without deviating from the principles of the present application so that the present application can be applicable to more specific application scenarios.

[0070] For example, in an alternative embodiment, although the above air preheater 15 and evaporator 14 are introduced as an example of being arranged independently of each other, the arrangement between the two is not unique, and those skilled in the art can adjust the arrangement of the two as long as the air preheater 15 is arranged on the upstream side of the evaporator 14. For example, the air preheater 15 and the evaporator 14 can be arranged as different pipe sections of the same heat exchanger. For example, the first row of pipes on the windward side of a finned heat exchanger with three rows of pipes is used as the air preheater 15, and the remaining two rows of pipes are used as the evaporator 14.

[0071] For another example, in another alternative embodiment, the air preheater 15 and the evaporator 14 are arranged side by side, which is only one possible embodiment, and in other embodiments, those skilled in the art can adjust the arrangement, such as arranging the air preheater 15 and the evaporator 14 in the same air duct and spacing them apart.

[0072] For another example, in another alternative embodiment, the first electrically controlled three-way valve 161, the second electrically controlled three-way valve 162, the third electrically controlled three-way valve 251, and the fourth electrically controlled three-way valve 252 can all be omitted, or only one or several of them can be provided, or the above one or several can be replaced by two-way valves. Such adjustment only has a certain impact on the control accuracy of the CO2 heat pump system, but does not deviate from the principles of the present application.

[0073] For another example, in another alternative embodiment, although the above embodiments are described by way of example in combination with the first electrically controlled three-way valve 161 and the second electrically controlled three-way valve 162 being arranged in the CO2 unit 10, and the third electrically controlled three-way valve 251 and the fourth electrically controlled three-way valve 252 being arranged in the heat cycle assembly 20, the arrangement positions of the first electrically controlled three-way valve 161, the second electrically controlled three-way valve 162, the third electrically controlled three-way valve 251 and the fourth electrically controlled three-way valve 252 are not fixed, and a person skilled in the art can adjust the arrangement positions thereof. For example, all the four electrically controlled three-way valves can be arranged in the CO2 unit 10 simultaneously, or can be arranged in the heat cycle assembly 20 simultaneously, or the four electrically controlled three-way valves can be distributed in the CO2 unit 10 and the heat cycle assembly 20 in any manner.

[0074] For another example, in another alternative embodiment, although the above embodiments are described by way of example in combination with the first pump body 17 and the four-way valve 18 being arranged in the CO2 unit 10, the arrangement of the first pump body 17 and the four-way valve 18 is not necessary, and a person skilled in the art can selectively omit one or all of the two.

[0075] For another example, in another alternative embodiment, the heat cycle assembly 20 is described by way of example in combination with the hot water supply tank 21, the heating pipeline 22 and the buffer water tank 24 being arranged, but the specific composition of the heat cycle assembly 20 is not fixed, and a person skilled in the art can select based on a specific application scenario. For example, the heat cycle assembly 20 can only be provided with the hot water supply tank 21 or the heating pipeline 22, or can be provided with both the hot water supply tank 21 and the heating pipeline 22 but omit the buffer water tank 24. Alternatively, the hot water supply tank 21 and the heating pipeline 22 can be arranged in series, the hot water supply tank 21 is arranged on the upstream side of the heating pipeline 22, and the like.

[0076] For another example, in another alternative embodiment, although the above embodiments are described in combination with the first on-off valve 271 and the second on-off valve 272 being arranged, the arrangement of the first on-off valve 271 and the second on-off valve 272 is not necessary, and in some embodiments, any one or all of the two can be omitted. In addition, the first on-off valve 271 and the second on-off valve 272 can be electrically controlled valves in other forms or even manual valves in addition to solenoid valves.

[0077] For another example, in another alternative embodiment, the arrangement of the second pump body 26 is not necessary, and a person skilled in the art can select whether to arrange the second pump body 26 based on a specific application scenario.

[0078] Of course, the above alternative embodiments can also be used in cross combination between the alternative embodiments and between the alternative embodiments and the preferred embodiments, so as to combine new embodiments to be applicable to more specific application scenarios.

[0079] Those skilled in the art will appreciate that the features of the various embodiments can be combined with each other in any combination within the scope of the application and form different embodiments. For example, in the claims of the application, any of the claimed embodiments can be used in any combination.

[0080] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will all fall within the protection scope of the present application.

Claims

1. A CO2 generator unit, characterized in that, The CO2 unit includes: compressor; An air cooler includes a first refrigerant port, a second refrigerant port, a first liquid port, and a second liquid port. A first heat exchange channel is formed between the first refrigerant port and the second refrigerant port, and a second heat exchange channel is formed between the first liquid port and the second liquid port. Heat exchange can occur between the first heat exchange channel and the second heat exchange channel. The first refrigerant port is connected to the exhaust port of the compressor, and the second liquid port is connected to the heating water outlet of the CO2 unit. A throttling element, wherein the first port of the throttling element is connected to the second refrigerant port; An evaporator, wherein the evaporator is an air-cooled evaporator, and the first port of the evaporator is connected to the second port of the throttling element, and the second port of the evaporator is connected to the suction port of the compressor; An air preheater is located upstream of the evaporator in the air inlet direction. The first port of the air preheater is connected to the heating return water interface of the CO2 unit, and the second port is connected to the first liquid port.

2. The CO2 unit according to claim 1, characterized in that, The air preheater and the evaporator are configured independently of each other; or The air preheater and the evaporator are different sections of the same heat exchanger.

3. The CO2 unit according to claim 1, characterized in that, The air preheater and the evaporator are arranged side by side.

4. The CO2 unit according to claim 1, characterized in that, The CO2 unit also includes a first electrically controlled three-way valve and a second electrically controlled three-way valve. The first port of the first electrically controlled three-way valve is connected to the heating return water port, the second port of the first electrically controlled three-way valve is connected to the first port of the air preheater, the first port of the second electrically controlled three-way valve is connected to the second liquid port, the second port of the second electrically controlled three-way valve is connected to the heating outlet water port, and the third port of the second electrically controlled three-way valve is connected to the third port of the first electrically controlled three-way valve.

5. The CO2 unit according to claim 1, characterized in that, The CO2 unit also includes a first pump body, the return port of the first pump body is connected to the second liquid port, and the discharge port of the first pump body is connected to the heating water outlet interface.

6. The CO2 unit according to claim 1, characterized in that, The CO2 unit also includes a four-way valve, the four ports of which are respectively connected to the exhaust port of the compressor, the first refrigerant port, the second port of the evaporator, and the suction port of the compressor.

7. A CO2 heat pump system, characterized in that, include: Thermal cycling components; According to any one of claims 1 to 6, the heat circulation component is connected to the heating outlet and the heating return interface respectively.

8. The CO2 heat pump system according to claim 7, characterized in that, The heat circulation assembly includes a hot water tank and a heating pipe. A heat exchange tube is installed in the hot water tank. The first end of the heat exchange tube and the first end of the heating pipe are both connected to the heating outlet interface. The second end of the heat exchange tube and the second end of the heating pipe are both connected to the heating return interface.

9. The CO2 heat pump system according to claim 8, characterized in that, The heat circulation assembly also includes a buffer water tank and a third electrically controlled three-way valve. The buffer water tank has a first inlet, a second inlet, and a first outlet. The first inlet is connected to the heating water outlet interface, and the first outlet is connected to the first end of the heating pipeline. The first interface of the third electrically controlled three-way valve is connected to the second end of the heating pipeline, the second interface of the third electrically controlled three-way valve is connected to the heating return water interface, and the third interface of the third electrically controlled three-way valve is connected to the second inlet of the buffer water tank.

10. The CO2 heat pump system according to claim 9, characterized in that, The heat circulation assembly further includes a fourth electrically controlled three-way valve, the first port of which is connected to the second end of the heat exchange tube, the second port of which is connected to the heating return water port, and the third port of which is connected to the second inlet of the buffer water tank; and / or The thermal circulation assembly also includes a second pump body, the drain port of which is connected to the second inlet of the buffer tank.

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