CO2 air source heat pump heat supply system

Abstract

The utility model provides a CO2 air source heat pump heat supply system. The CO2 air source heat pump heat supply system comprises a first-stage heat pump circulation system, a second-stage heat pump circulation system and a heat supply system body. The first-stage heat pump circulating system is used for providing heat for the second-stage heat pump circulating system and the heat supply system, the second-stage heat pump circulating system is used for providing heat for the heat supply system, the first-stage heat pump circulating system and the second-stage heat pump circulating system can be connected in series or in parallel to provide heat for the heat supply system, and the heat supply system is used for providing heat for a user side; according to the heat supply system, by adjusting the series-parallel connection heat supply mode between the first-stage heat pump circulation system and the second-stage heat pump circulation system and the flow of the first medium, the flow of the second medium and the flow of the third medium, the heat exchange proportion between the heat supply system and the first-stage heat pump circulation system and the heat exchange proportion between the heat supply system and the second-stage heat pump circulation system can be adjusted; the overall energy efficiency ratio of the system is improved, and it is ensured that the air source heat pump can operate normally when the environment temperature is lower than-20 DEG C.

Description

Technical Field

[0001] The utility model relates to the technical field of energy conservation and environmental protection, and in particular to a CO2 air source heat pump heating system. Background Art

[0002] Air source heat pumps use a small amount of electricity to drive the compressor, absorbing low-grade heat energy from the air and converting it into high-grade heat energy for indoor heating. Compared with coal-fired / gas-fired boilers, electric boilers and other heating methods, they have the advantages of energy saving, environmental protection, and easy installation. They have been used on a certain scale in the heating field of residents in northern my country. However, most of the existing air source heat pumps are based on conventional refrigerants (R22, R410A, etc.). When the ambient temperature drops, the evaporation temperature drops, the evaporation pressure also decreases, the compressor pressure ratio increases, and the compressor exhaust temperature rises, which can easily cause the unit to overheat and stop operating. Although some companies have also developed steam injection enthalpy increase and liquid injection cooling technologies to alleviate this problem to a certain extent, when the ambient temperature is below -20℃, the above technologies still cannot effectively respond. Air source heat pumps still stop operating due to overheat protection and cannot operate stably.

[0003] In addition, conventional refrigerants used in existing air source heat pumps, such as R22 and R410A, mostly have high ODP and GWP values, which can easily cause ozone layer damage and lead to an increasingly serious greenhouse effect. Faced with severe environmental and ecological problems, the process of replacing conventional refrigerants worldwide is accelerating.

[0004] As a natural refrigerant, CO2 is non-toxic and non-flammable, has stable chemical properties, and has good safety. It has no destructive effect on the ozone layer, an ODP of 0, and a global warming potential index GWP of 1, with excellent environmental performance. In addition, CO2 still has a high density, thermal conductivity and specific heat capacity in low-temperature environments, and a low dynamic viscosity and surface tension, making it more adaptable to low ambient temperature conditions. Utility Model Content

[0005] In view of this, the present invention aims to propose a CO2 air source heat pump heating system to solve the problem in the prior art that the air source heat pump stops operating due to overheating protection when the ambient temperature is lower than -20°C.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0007] A CO2 air source heat pump heating system, comprising a first stage heat pump circulation system, a second stage heat pump circulation system and a heating system;

[0008] The first-stage heat pump circulation system is used to provide heat to the second-stage heat pump circulation system and the heating system, and the second-stage heat pump circulation system is used to provide heat to the heating system. The first-stage heat pump circulation system and the second-stage heat pump circulation system can be connected in series or in parallel to provide heat to the heating system. The heating system is used to provide heat to the user end;

[0009] By adjusting the flow of the first medium in the first-stage heat pump circulation system, the second medium in the second-stage heat pump circulation system and the third medium in the heating system, the heat exchange ratio between the heating system and the first-stage heat pump circulation system and the second-stage heat pump circulation system can be adjusted to control the water outlet temperature at the user end.

[0010] The CO2 air source heat pump heating system described in the present application, the second-stage heat pump circulation system can further utilize the remaining heat energy in the first-stage heat pump circulation system. By adjusting the series-parallel heating mode between the first-stage heat pump circulation system and the second-stage heat pump circulation system, as well as the flow rates of the first medium, the second medium and the third medium, the heat exchange ratio between the heating system and the first-stage heat pump circulation system and the second-stage heat pump circulation system can be adjusted, thereby improving the overall energy efficiency of the system, more efficiently utilizing the heat energy in the air, and ensuring that the air source heat pump can operate normally when the ambient temperature is below -20°C.

[0011] Furthermore, the first-stage heat pump circulation system includes a first compressor, an air cooler, a second evaporator, a regenerator, a first expansion valve and a first evaporator, and the regenerator includes a first heat regeneration channel and a second heat regeneration channel;

[0012] The first compressor, the air cooler, the second evaporator, the first heat recovery channel, the first expansion valve, the first evaporator and the second heat channel are connected in series through a first connecting pipe, and the first medium in the first connecting pipe exchanges heat with the third medium in the heating system in the air cooler.

[0013] This heat exchange method helps reduce temperature fluctuations of CO2 refrigerant during circulation and improves system stability and reliability.

[0014] Furthermore, the second-stage heat pump circulation system includes a second compressor, a condenser, a second expansion valve and a second evaporator. The second compressor, condenser, second expansion valve and second evaporator are connected in series through a second connecting pipe. The second medium in the second connecting pipe exchanges heat with the third medium in the heating system in the condenser.

[0015] By setting up a second-stage heat pump circulation system, the remaining heat energy in the first-stage heat pump circulation system can be further utilized, thereby improving the overall energy efficiency of the system and ensuring stable operation of the system.

[0016] Furthermore, the heating system includes a third communicating pipe, which is connected to the condenser and the air cooler, and the condenser and the air cooler are connected in parallel or in series. The first medium in the first communicating pipe and the third medium in the third communicating pipe exchange heat in the air cooler, and the second medium in the second communicating pipe and the third medium in the third communicating pipe exchange heat in the condenser.

[0017] This setting enables the third connecting pipe to be flexibly connected to the condenser and air cooler, and can flexibly adjust the path and method of heat exchange according to the actual needs of the user end, thereby improving the flexibility and adaptability of the system and better meeting the heating needs of different users under different conditions.

[0018] Furthermore, the third communicating pipe includes a first heat exchange branch and a second heat exchange branch, the first heat exchange branch is connected to the air cooler, and the second heat exchange branch is connected to the condenser.

[0019] This setting enables the system to select different heat exchange methods according to the actual needs of the user, thereby better meeting the user's heating needs under different conditions.

[0020] Furthermore, the third connecting pipe also includes a third heat exchange branch, and the first heat exchange branch and the second heat exchange branch are connected through the third heat exchange branch.

[0021] This setup enables the air cooler and condenser to be connected in series, optimizing the heat exchange pattern of the system.

[0022] Furthermore, the heating system includes a water pump, which is used to push the third medium to flow in the third connecting pipe.

[0023] This setting can flexibly adjust the flow of the heating system according to actual needs to meet the heating needs of users under different conditions.

[0024] Furthermore, the first heat exchange branch is provided with a first valve, the second heat exchange branch is provided with a second valve, and the third heat exchange branch is provided with a third valve. By adjusting the states of the first valve, the second valve and the third valve, the flow rate of the third medium in the first heat exchange branch, the second heat exchange branch and the third heat exchange branch can be controlled.

[0025] By adjusting the opening of the first valve, the second valve and the third valve, the flow of the third medium in the first heat exchange branch, the second heat exchange branch and the third heat exchange branch can be accurately controlled, thereby flexibly adjusting the heat exchange mode between the heating system and the first-stage heat pump circulation system and the second-stage heat pump circulation system to meet the user's heating needs under different conditions.

[0026] Compared with the existing technology, the CO2 air source heat pump heating system described in the present invention has the following advantages: the second-stage heat pump circulation system can further utilize the remaining heat energy in the first-stage heat pump circulation system, and by adjusting the series-parallel heating mode between the first-stage heat pump circulation system and the second-stage heat pump circulation system, as well as the flow rate of the first medium, the second medium and the third medium, the heat exchange ratio between the heating system and the first-stage heat pump circulation system and the second-stage heat pump circulation system can be adjusted, thereby improving the overall energy efficiency of the system, more efficiently utilizing the heat energy in the air, and ensuring that the air source heat pump can still operate normally when the ambient temperature is below -20°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a diagram of a heating system when the return water temperature at the user end is less than 25°C according to an embodiment of the present utility model;

[0028] Figure 2 This is a diagram of a heating system when the outlet water temperature at the user end is 70°C to 80°C according to an embodiment of the present utility model;

[0029] Figure 3 This is a diagram of a heating system when the outlet water temperature at the user end is between 80°C and 95°C according to an embodiment of the present utility model;

[0030] Figure 4 This is a diagram of a heating system when the outlet water temperature at the user end is between 95°C and 120°C as described in an embodiment of the present utility model.

[0031] Description of reference numerals:

[0032] 1. Water pump; 2. First valve; 3. Condenser; 4. Second expansion valve; 5. Second compressor; 6. Second evaporator; 7. Regenerator; 8. First expansion valve; 9. First evaporator; 10. First compressor; 11. Air cooler; 12. Third valve; 13. Second valve; 14. User end; 110. First-stage heat pump circulation system; 111. First connecting pipe; 120. Second-stage heat pump circulation system; 121. Second connecting pipe; 130. Heating system; 131. Third connecting pipe; 1311. First heat exchange branch; 1312. Second heat exchange branch; 1313. Third heat exchange branch. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0034] Example 1

[0035] like Figure 1-4As shown, a CO2 air source heat pump heating system includes a first stage heat pump circulation system 110, a second stage heat pump circulation system 120 and a heating system 130;

[0036] The first-stage heat pump circulation system 110 is used to provide heat to the second-stage heat pump circulation system 120 and the heating system 130. The second-stage heat pump circulation system 120 is used to provide heat to the heating system 130. The first-stage heat pump circulation system 110 and the second-stage heat pump circulation system 120 can be connected in series or in parallel to provide heat to the heating system 130. The heating system 130 is used to provide heat to the user end 14.

[0037] By adjusting the flow rates of the first medium in the first-stage heat pump circulation system 110, the second medium in the second-stage heat pump circulation system 120, and the third medium in the heating system 130, the heat exchange ratio between the heating system 130 and the first-stage heat pump circulation system 110 and the second-stage heat pump circulation system 120 can be adjusted to control the outlet water temperature at the user end 14.

[0038] The CO2 air source heat pump heating system described in the present application, the second-stage heat pump circulation system 120 can further utilize the remaining heat energy in the first-stage heat pump circulation system 110. By adjusting the series-parallel heating mode between the first-stage heat pump circulation system 110 and the second-stage heat pump circulation system 120, as well as the flow rates of the first medium, the second medium and the third medium, the heat exchange ratio between the heating system 130 and the first-stage heat pump circulation system 110 and the second-stage heat pump circulation system 120 can be adjusted, thereby improving the overall energy efficiency of the system, more efficiently utilizing the heat energy in the air, and ensuring that the air source heat pump can operate normally when the ambient temperature is below -20°C.

[0039] As a preferred example of the present application, the first-stage heat pump circulation system 110 includes a first compressor 10, an air cooler 11, a second evaporator 6, a regenerator 7, a first expansion valve 8 and a first evaporator 9, wherein the regenerator 7 includes a first heat regeneration channel and a second heat regeneration channel;

[0040] The first compressor 10, the air cooler 11, the second evaporator 6, the first heat recovery channel, the first expansion valve 8, the first evaporator 9 and the second heat channel are connected in series through the first connecting pipe 111. The first medium in the first connecting pipe 111 and the third medium in the heating system 130 exchange heat in the air cooler 11.

[0041] Specifically, the first medium is CO2 refrigerant, which evaporates in the first evaporator 9 and absorbs heat from the air. At this time, the CO2 refrigerant is in a low-temperature, low-pressure subcritical state. The CO2 refrigerant flowing out of the first evaporator 9 becomes a high-temperature, high-pressure supercritical state after being compressed by the first compressor 10. The high-temperature CO2 refrigerant flowing out of the first compressor 10 heats the medium in the heating system in the air cooler 11. The CO2 refrigerant flowing out of the air cooler 11 becomes a low-temperature, high-pressure state. The CO2 refrigerant flowing out of the air cooler 11 enters the second evaporator 6 to exchange heat with the medium in the second-stage heat pump circulation system.

[0042] The low-temperature, low-pressure CO2 refrigerant flowing out of the first evaporator 9 flows through the first heat regeneration channel, and the low-temperature, high-pressure CO2 refrigerant flowing out of the second evaporator 6 flows through the second heat regeneration channel. The low-temperature, low-pressure CO2 refrigerant and the low-temperature, high-pressure CO2 refrigerant exchange heat in the regenerator 7. This heat exchange method helps to reduce the temperature fluctuation of the CO2 refrigerant during the circulation process and improve the stability and reliability of the system.

[0043] The refrigerant flowing out of the regenerator 7 is throttled by the first expansion valve 8 and becomes a low-temperature and low-pressure gas-liquid two-phase mixture and enters the first evaporator 9, completing the circulation of the first-stage heat pump circulation system 110.

[0044] As a preferred example of the present application, the second-stage heat pump circulation system 120 includes a second compressor 5, a condenser 3, a second expansion valve 4 and a second evaporator 6. The second compressor 5, the condenser 3, the second expansion valve 4 and the second evaporator 6 are connected in series through a second connecting pipe 121. The second medium in the second connecting pipe 121 exchanges heat with the third medium in the heating system 130 in the condenser 3.

[0045] Specifically, when the ambient temperature is lower than -20°C, the single-stage heat pump system may trigger overheating protection and stop operating due to the high exhaust temperature of the compressor. By setting up the second-stage heat pump circulation system 120, the remaining heat energy in the first-stage heat pump circulation system 110 can be further utilized to improve the overall energy efficiency of the system, effectively reduce the working pressure and temperature of the single heat pump, thereby improving the low-temperature adaptability and stability of the system, and ensuring that the system can operate stably.

[0046] As a preferred example of the present application, the heating system 130 includes a third communicating pipe 131, which is connected to the condenser 3 and the air cooler 11, and the condenser 3 and the air cooler 11 are connected in parallel or in series. The first medium in the first communicating pipe 111 and the third medium in the third communicating pipe 131 exchange heat in the air cooler 11, and the second medium in the second communicating pipe 121 and the third medium in the third communicating pipe 131 exchange heat in the condenser 3.

[0047] Specifically, this setting enables the third connecting pipe 131 to be flexibly connected to the condenser 3 and the air cooler 11, and can flexibly adjust the path and method of heat exchange according to the actual needs of the user end 14, thereby improving the flexibility and adaptability of the system and being able to better meet the heating needs of different users under different conditions.

[0048] As a preferred example of the present application, the third connecting pipe 131 includes a first heat exchange branch 1311 and a second heat exchange branch 1312 , wherein the first heat exchange branch 1311 is connected to the air cooler 11 , and the second heat exchange branch 1312 is connected to the condenser 3 .

[0049] Specifically, this setting enables the system to select different heat exchange modes according to the actual needs of the user end 14, so as to better meet the user's heating needs under different conditions.

[0050] As a preferred example of the present application, the third connecting pipe 131 further includes a third heat exchange branch 1313 , and the first heat exchange branch 1311 and the second heat exchange branch 1312 are connected through the third heat exchange branch 1313 .

[0051] Specifically, this arrangement enables the air cooler 11 and the condenser 3 to be connected in series, thereby optimizing the heat exchange mode of the system. At the same time, it also increases the redundancy of the system and reduces the overall failure of the system due to branch blockage.

[0052] As a preferred example of the present application, the heating system 130 includes a water pump 1 , which is used to push the third medium to flow in the third connecting pipe 131 .

[0053] Specifically, this setting can flexibly adjust the flow of the heating system 130 according to actual needs to meet the user's heating needs under different conditions. At the same time, it can ensure the stable circulation of the third medium in the third connecting pipe 131, avoiding problems such as uneven heating or system failure caused by poor medium flow.

[0054] As a preferred example of the present application, the first heat exchange branch 1311 is provided with a first valve 2, the second heat exchange branch 1312 is provided with a second valve 13, and the third heat exchange branch 1313 is provided with a third valve 12. By adjusting the states of the first valve 2, the second valve 13 and the third valve 12, the flow rate of the third medium in the first heat exchange branch 1311, the second heat exchange branch 1312 and the third heat exchange branch 1313 can be controlled.

[0055] Specifically, by adjusting the opening of the first valve 2, the second valve 13 and the third valve 12, the flow of the third medium in the first heat exchange branch 1311, the second heat exchange branch 1312 and the third heat exchange branch 1313 can be accurately controlled, thereby flexibly adjusting the heat exchange mode between the heating system 130 and the first-stage heat pump circulation system 110 and the second-stage heat pump circulation system 120 to meet the user's heating needs under different conditions.

[0056] The present invention also provides a heating method for a CO2 air source heat pump heating system, which is used in the above-mentioned CO2 air source heat pump heating system, comprising the steps of:

[0057] S1: Detect and determine whether the return water temperature of the user end 14 is less than 25°C. If so, proceed to step S2; if not, proceed to step 3;

[0058] S2: The first valve 2 is opened, the second valve 13 and the third valve 12 are closed, and the water pump 1 pushes the third medium to circulate through the first heat exchange branch 1311. The third medium exchanges heat with the first medium in the air cooler 11.

[0059] S3: Determine the outlet water temperature required by the user terminal 14. If the outlet water temperature is between 70°C and 80°C, proceed to step 4. If the outlet water temperature is between 80°C and 95°C, proceed to step 5. If the outlet water temperature is between 95°C and 120°C, proceed to step 6.

[0060] S4: The first valve 2 and the second valve 13 are opened, the third valve 12 is closed, the first heat exchange branch 1311 and the second heat exchange branch 1312 are connected in parallel, and the water pump 1 pushes the third medium to circulate through the first heat exchange branch 1311 and the second heat exchange branch 1312. The third medium exchanges heat with the first medium in the air cooler 11 and with the second medium in the condenser 3.

[0061] S5: The first valve 2 and the second valve 13 are closed, and the third valve 12 is opened. The third medium circulates through the water pump 1, the condenser 3, the third valve 12, and the air cooler 11 in sequence. The third medium exchanges heat with the first medium in the air cooler 11 and with the second medium in the condenser 3.

[0062] S6: the first valve 2 and the third valve 12 are closed, the second valve 13 is opened, and the third medium circulates through the water pump 1, the condenser 3 and the second valve 13 in sequence, and the third medium exchanges heat with the second medium in the condenser 3.

[0063] Specifically, in S2, the second compressor 5 stops running and the first valve 2 is opened, so that heat exchange can be performed between the first-stage heat pump circulation system 110 and the heating system 130. In S4, by adjusting the opening of the first valve 2 and the second valve 13, the flow of the third medium in the first heat exchange branch 1311 and the second heat exchange branch 1312 can be controlled to adjust the outlet water temperature of the user end 14. In S5, the third medium flows through the condenser 3 and the air cooler 11 in sequence, which can further increase the outlet water temperature of the user end 14 based on S4. In S6 The heating system 130 only exchanges heat with the condenser 3, so that the outlet water temperature of the user end 14 reaches the highest. This setting can improve the overall energy efficiency of the system by controlling the heat exchange method between the heating system 130 and the first-stage heat pump circulation system 110 and the second-stage heat pump circulation system 120 according to the return water temperature and outlet water temperature of the user end 14, more efficiently utilize the heat energy in the air, flexibly adjust the outlet water temperature of the user end 14, improve the adaptability and heating efficiency of the system, and ensure that the air source heat pump can operate normally when the ambient temperature is below -20°C.

[0064] As a preferred example of the present application, in S4, the second medium is set to R134a or R515B refrigerant; in S5, the second medium is set to R515B refrigerant; in S6, the second medium is set to R245fa refrigerant.

[0065] Specifically, selecting different refrigerants based on the user-end water outlet temperature requirements can optimize the system performance, ensure the stable operation of the heat pump system under high load, and avoid problems such as overheating protection.

[0066] The CO2 air source heat pump heating system described in the present application has the following advantages: the second-stage heat pump circulation system 120 can further utilize the remaining heat energy in the first-stage heat pump circulation system 110, and by adjusting the series-parallel heating mode between the first-stage heat pump circulation system 110 and the second-stage heat pump circulation system 120, as well as the flow rates of the first medium, the second medium and the third medium, the heat exchange ratio between the heating system 130 and the first-stage heat pump circulation system 110 and the second-stage heat pump circulation system 120 can be adjusted, thereby improving the overall energy efficiency of the system and utilizing the heat energy in the air more efficiently; by adjusting the opening of the first valve 2, the second valve 13 and the third valve 12, the flow rate of the third medium in the first heat exchange branch 1311, the second heat exchange branch 1312 and the third heat exchange branch 1313 can be precisely controlled, thereby flexibly adjusting the heat exchange mode between the heating system 130 and the first-stage heat pump circulation system 110 and the second-stage heat pump circulation system 120, ensuring that the air source heat pump can still operate normally when the ambient temperature is below -20°C. Although the present invention is disclosed as above, it is not limited thereto. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope defined by the claims.

Claims

1. A CO2 air source heat pump heating system, characterized in that: It includes a first-stage heat pump circulation system (110), a second-stage heat pump circulation system (120) and a heating system (130); The first-stage heat pump circulation system (110) is used to provide heat to the second-stage heat pump circulation system (120) and the heating system (130); the second-stage heat pump circulation system (120) is used to provide heat to the heating system (130); the first-stage heat pump circulation system (110) and the second-stage heat pump circulation system (120) can be connected in series or in parallel to provide heat to the heating system (130); and the heating system (130) is used to provide heat to the user end (14); By adjusting the flow rates of a first medium in the first-stage heat pump circulation system (110), a second medium in the second-stage heat pump circulation system (120), and a third medium in the heating system (130), the heat exchange ratio between the heating system (130) and the first-stage heat pump circulation system (110) and the second-stage heat pump circulation system (120) can be adjusted, thereby controlling the outlet water temperature at the user end (14).

2. The CO2 air source heat pump heating system according to claim 1, characterized in that: The first-stage heat pump circulation system (110) comprises a first compressor (10), an air cooler (11), a second evaporator (6), a regenerator (7), a first expansion valve (8) and a first evaporator (9), wherein the regenerator (7) comprises a first heat regeneration channel and a second heat regeneration channel; The first compressor (10), the air cooler (11), the second evaporator (6), the first heat regeneration channel, the first expansion valve (8), the first evaporator (9) and the second heat channel are connected in series via a first communicating pipe (111); a first medium in the first communicating pipe (111) exchanges heat with a third medium in the heating system (130) in the air cooler (11).

3. The CO2 air source heat pump heating system according to claim 1, characterized in that: The second-stage heat pump circulation system (120) comprises a second compressor (5), a condenser (3), a second expansion valve (4) and a second evaporator (6); the second compressor (5), the condenser (3), the second expansion valve (4) and the second evaporator (6) are connected in series via a second communicating pipe (121); a second medium in the second communicating pipe (121) exchanges heat with a third medium in the heating system (130) in the condenser (3).

4. The CO2 air source heat pump heating system according to claim 1, characterized in that: The heating system (130) includes a third communicating pipe (131), the third communicating pipe (131) is connected to the condenser (3) and the air cooler (11), and the condenser (3) and the air cooler (11) are connected in parallel or in series. The first medium in the first communicating pipe (111) and the third medium in the third communicating pipe (131) exchange heat in the air cooler (11), and the second medium in the second communicating pipe (121) and the third medium in the third communicating pipe (131) exchange heat in the condenser (3).

5. The CO2 air source heat pump heating system according to claim 4, characterized in that: The third connecting pipe (131) comprises a first heat exchange branch (1311) and a second heat exchange branch (1312), wherein the first heat exchange branch (1311) is connected to the air cooler (11), and the second heat exchange branch (1312) is connected to the condenser (3).

6. The CO2 air source heat pump heating system according to claim 5, characterized in that: The third connecting pipe (131) includes a third heat exchange branch (1313). The first heat exchange branch (1311) and the second heat exchange branch (1312) are connected via the third heat exchange branch (1313).

7. The CO2 air source heat pump heating system according to claim 4, characterized in that: The heating system (130) comprises a water pump (1), and the water pump (1) is used to push the third medium to flow in the third communicating pipe (131).

8. The CO2 air source heat pump heating system according to claim 6, characterized in that: The first heat exchange branch (1311) is provided with a first valve (2), the second heat exchange branch (1312) is provided with a second valve (13), and the third heat exchange branch (1313) is provided with a third valve (12). By adjusting the states of the first valve (2), the second valve (13) and the third valve (12), the flow rates of the third medium in the first heat exchange branch (1311), the second heat exchange branch (1312) and the third heat exchange branch (1313) can be controlled.

Images