Low-temperature enthalpy-increasing heat recovery system
By introducing an economizer into the liquid receiver, a low-temperature enthalpy-increasing heat recovery system was designed, which solved the problems of adaptability and efficiency of the heat recovery system in low-temperature environments, realized stable distribution of refrigerant and efficient energy utilization, and improved the system's heating capacity in low-temperature environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GREE ELECTRIC APPLIANCE INC OF ZHUHAI
- Filing Date
- 2025-05-28
- Publication Date
- 2026-04-28
AI Technical Summary
Existing heat recovery systems have poor adaptability to low-temperature environments, resulting in reduced heat absorption capacity of the evaporator, low heating efficiency, and immature integration of gas replenishment technology, thus limiting heat recovery efficiency.
An economizer is introduced on the basis of the liquid receiver. The compressor unit is replenished with gas through the enthalpy-increasing branch of the economizer. A low-temperature enthalpy-increasing heat recovery system is designed, including a compressor unit, three heat exchangers and a liquid receiver, to achieve stable distribution of refrigerant and efficient energy utilization.
It improves the operating performance of the heat recovery system in low-temperature environments, ensures system stability and energy efficiency, adapts to multiple working modes, and increases the heating output in low-temperature environments.
Smart Images
Figure CN224175367U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of heat pump system technology, and in particular to a low-temperature enthalpy-increasing heat recovery system. Background Technology
[0002] Heat pumps, as highly efficient energy conversion devices, extract heat from the environment and transfer it to locations requiring heat through refrigerant circulation. Driven by energy conservation and emission reduction policies, they have been widely adopted in recent years. Heat recovery technology, an important branch of heat pump systems, aims to recover heat from waste heat or low-grade heat sources to improve energy efficiency and reduce dependence on traditional energy sources.
[0003] Currently, the performance of heat recovery heat pump systems mainly depends on heat exchanger design and fluid flow path optimization. However, existing technologies still have the following limitations:
[0004] 1. Poor adaptability to low-temperature environments: When the ambient temperature is cold (e.g., below -10℃), the heat absorption capacity of the evaporator of the traditional heat recovery system decreases significantly, resulting in a significant reduction in the system's heating efficiency (COP), making it difficult to meet the needs of cold regions;
[0005] 2. Insufficient application of gas replenishment technology: Although enthalpy-increasing gas replenishment technology (such as jet enthalpy increase) has been applied in ordinary heat pumps, its integration scheme in heat recovery systems is still immature. Heat recovery systems have multiple working modes and flexible refrigerant flow, and the matching problem between gas replenishment pipelines and heat pump systems has not yet been effectively solved.
[0006] 3. Heat recovery efficiency bottleneck: The heat recovery rate of conventional single-stage compression heat pumps is limited by the refrigerant cycle characteristics. Especially when dealing with low-grade heat sources, the system is difficult to balance high energy efficiency and stable output.
[0007] Therefore, how to design a heat recovery system that is suitable for efficient operation in low-temperature environments is a pressing technical issue for the industry. Utility Model Content
[0008] To address the shortcomings of existing heat recovery systems in poor adaptability to low-temperature environments, this invention proposes a low-temperature enthalpy-increasing heat recovery system. This system introduces an economizer into the liquid receiver and uses the enthalpy-increasing branch of the economizer to replenish the compressor unit, thereby improving the operating performance of the heat recovery system.
[0009] The technical solution adopted in this utility model is to design a low-temperature enthalpy-increasing heat recovery system, including: a compressor unit, three heat exchangers and a liquid receiver. The compressor unit can be connected to any two heat exchangers to form a refrigerant circulation loop. The inlet pipe of the liquid receiver is connected to the condenser outlet side of the refrigerant circulation loop. The outlet pipe of the liquid receiver is connected to an economizer. The main circuit of the economizer is connected back to the refrigerant circulation loop. The enthalpy-increasing branch of the economizer is connected in series with an auxiliary circuit throttle valve and connected to the gas injection port of the compressor unit.
[0010] Furthermore, the three heat exchangers are the first heat exchanger, the second heat exchanger, and the third heat exchanger. The exhaust side of the compressor unit can be switched to connect to the first end of any heat exchanger, and the second end of each heat exchanger is connected to the inlet pipe of the liquid receiver through a valve. The second end of the first heat exchanger and the second end of the third heat exchanger are connected through a throttling pipeline, which is connected in series with a first throttling valve and a second throttling valve. The main line of the economizer is connected between the first throttling valve and the second throttling valve.
[0011] In some embodiments, the first heat exchanger is an air conditioning water heat exchanger, the second heat exchanger is a hot water heat exchanger, and the third heat exchanger is an outdoor heat exchanger.
[0012] Furthermore, the operating modes of the heat recovery system include at least one of the following: hot water mode, cooling mode, heating mode, and cooling and heating water mode.
[0013] When the heat recovery system is operating in hot water mode, the second heat exchanger acts as a condenser, the third heat exchanger acts as an evaporator, and the first heat exchanger does not participate in the refrigerant cycle.
[0014] And / or when the heat recovery system is operating in cooling mode, the first heat exchanger acts as an evaporator, the third heat exchanger acts as a condenser, and the second heat exchanger does not participate in the refrigerant cycle;
[0015] And / or when the heat recovery system is operating in heating mode, the first heat exchanger acts as a condenser, the third heat exchanger acts as an evaporator, and the second heat exchanger does not participate in the refrigerant cycle;
[0016] And / or when the heat recovery system is operating in cooling and heating water mode, the first heat exchanger acts as an evaporator, the second heat exchanger acts as a condenser, and the third heat exchanger does not participate in the refrigerant cycle.
[0017] Furthermore, the auxiliary throttle valve is closed when the heat recovery system is operating in hot water mode.
[0018] Furthermore, the compressor unit is connected to three heat exchangers through two four-way valves; the D end of the first four-way valve is connected to the discharge side of the compressor unit, the E end is connected to the first end of the first heat exchanger, the S end is connected to the suction side of the compressor unit, and the C end is connected to the D end of the second four-way valve; the C end of the second four-way valve is connected to the first end of the third heat exchanger, the E end is connected to the first end of the second heat exchanger, and the S end is connected to the suction side of the compressor unit.
[0019] Furthermore, the valve is a one-way valve, which only allows refrigerant to flow to the receiver.
[0020] In some embodiments, the heat recovery system is a variable frequency heat pump system. The IPM module of the heat recovery system is equipped with a heat dissipation pipe, which is connected in series with the inlet pipe of the liquid receiver so that the refrigerant sent to the liquid receiver passes through the heat dissipation pipe.
[0021] Furthermore, a filter is installed at the first and / or second end of each heat exchanger.
[0022] Furthermore, the compressor unit includes two compressors connected in parallel.
[0023] Compared with existing technologies, this invention introduces an economizer into the liquid receiver. The economizer is connected to the outlet pipe of the liquid receiver, which buffers pressure fluctuations at the condenser outlet, ensuring a stable refrigerant flow for the economizer. The economizer then diverts the refrigerant, with the main path ensuring liquid supply to the evaporator and the enthalpy-enhancing branch precisely replenishing gas, thus improving compressor unit efficiency and achieving high-efficiency energy utilization. Through the liquid receiver's flow stabilization and the economizer's diversion, rational refrigerant distribution and low-temperature enthalpy enhancement are achieved, balancing system stability and energy efficiency improvement. Attached Figure Description
[0024] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:
[0025] Figure 1 This is a schematic diagram of the system connection of this utility model;
[0026] Figure 2 These are schematic diagrams of system connections in some embodiments;
[0027] Figure 3 These are system connection diagrams for other embodiments;
[0028] Figure 4 This is a schematic diagram of the refrigerant flow in hot water mode;
[0029] Figure 5 This is a schematic diagram of the refrigerant flow in the cooling mode;
[0030] Figure 6 This is a schematic diagram of the refrigerant flow in the heating mode;
[0031] Figure 7 This is a schematic diagram of the refrigerant flow in a cooling and heating water supply mode;
[0032] Figure descriptions: 1. Compressor unit; 2. First heat exchanger; 3. Second heat exchanger; 4. Third heat exchanger; 5. Liquid receiver; 6. Economizer; 7. First check valve; 8. Second check valve; 9. Third check valve; 10. First throttle valve; 11. Second throttle valve; 12. Auxiliary throttle valve; 13. First four-way valve; 14. Second four-way valve; 15. IPM module; 16. Gas-liquid separator; 17. Filter; 18. Oil separator; 19. Oil return valve. Detailed Implementation
[0033] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.
[0034] like Figures 1 to 3 As shown, the heat recovery system proposed in this utility model has multiple heat exchangers and the refrigerant flow direction is flexible and variable. In order to adapt the gas injection technology to the heat recovery system, an economizer is introduced on the basis of the liquid receiver. The enthalpy-increasing branch of the economizer is used to inject gas into the compressor to improve the operating performance of the heat recovery system.
[0035] Specifically, the low-temperature enthalpy-increasing heat recovery system includes: a compressor unit 1, three heat exchangers, and a liquid receiver 5. The compressor unit 1 contains at least one compressor and can be connected to any two heat exchangers to form a refrigerant circulation loop. The inlet pipe of the liquid receiver 5 is connected to the condenser outlet side of the refrigerant circulation loop, and the outlet pipe of the liquid receiver 5 is connected to an economizer 6. The main circuit of the economizer 6 is connected back to the refrigerant circulation loop, and the enthalpy-increasing branch of the economizer 6 is connected in series with an auxiliary circuit throttle valve 12 to the gas supply port of the compressor unit 1.
[0036] High-temperature and high-pressure refrigerant is discharged from compressor unit 1 and enters the condenser for heat exchange. After being subcooled into high-pressure liquid refrigerant, a portion of it enters the receiver 5. The refrigerant in receiver 5 is then subcooled by economizer 6 and divided into two paths—the main path and the enthalpy-increasing branch. The main path sends the refrigerant back to the refrigerant circulation loop. The enthalpy-increasing branch is throttled at the auxiliary path throttle valve 12 and then enters economizer 6 to evaporate into a relatively low-temperature gaseous refrigerant, which enters compressor unit 1 through the gas injection port.
[0037] This invention connects the economizer 6 to the outlet pipe of the receiver 5. The receiver 5 buffers pressure fluctuations at the condenser outlet, ensuring a stable refrigerant flow for the economizer 6. The economizer 6 then distributes the refrigerant, with the main path ensuring liquid supply to the evaporator and the enthalpy-enhancing branch precisely replenishing gas, thereby improving the compressor unit's efficiency and achieving high-efficiency energy utilization. Furthermore, the gas replenishment lowers the exhaust temperature, allowing the heat recovery system to maintain high heating capacity even under extreme conditions such as low temperatures. This design, through receiver flow stabilization and economizer distribution, achieves rational refrigerant distribution and low-temperature enthalpy enhancement, balancing system stability and energy efficiency improvement.
[0038] like Figures 1 to 3 As shown, in some embodiments of this utility model, the three heat exchangers are the first heat exchanger 2, the second heat exchanger 3, and the third heat exchanger 4. For ease of understanding, the first end and the second end of each heat exchanger have been marked on the connection diagram of the heat recovery system, with the first end marked as "①" and the second end marked as "②".
[0039] The discharge side of compressor unit 1 can be switched to connect to the first end ① of any heat exchanger, and the second end ② of each heat exchanger is connected to the inlet pipe of receiver 5 through a valve. When compressor unit 1 is connected to the first end ① of a heat exchanger, the heat exchanger acts as a condenser, the second end ② of the heat exchanger is the condenser outlet side, and the refrigerant flowing out of the second end ② can enter receiver 5 through the valve.
[0040] The second end ② of the first heat exchanger 2 is connected to the second end ② of the third heat exchanger 4 through a throttling pipe. The throttling pipe is connected in series with a first throttling valve 10 and a second throttling valve 11. The first throttling valve 10 is close to the first heat exchanger 2, and the second throttling valve 11 is close to the third heat exchanger 4. The main line of the economizer 6 is connected between the first throttling valve 10 and the second throttling valve 11. The refrigerant flowing out of the main line can enter the first heat exchanger 2 through the first throttling valve 10, and the refrigerant flowing out of the main line can also enter the third heat exchanger 4 through the second throttling valve 11. The specific flow direction depends on the working mode of the heat recovery system.
[0041] This design simplifies the connection piping of the heat recovery system. The refrigerant distribution status of the three heat exchangers is controlled by the first throttle valve 10, the second throttle valve 11, and the auxiliary throttle valve 12. While maintaining the simplicity of the piping, it achieves high-precision regulation of refrigerant flow rate and direction, and is especially suitable for heat recovery systems with diverse operating modes.
[0042] In addition, the valves mentioned above can be control valves with switchable on / off states or check valves. The check valve of the first heat exchanger 2 is the second check valve 8, the check valve of the second heat exchanger 3 is the first check valve 7, and the check valve of the third heat exchanger 4 is the third check valve 9. By utilizing the one-way conduction characteristic of the check valve, it is ensured that the refrigerant can only flow from the heat exchanger to the receiver 5, avoiding the refrigerant backflow during different mode switching, which would cause system pressure disturbance or efficiency reduction. No additional electrical control signal is required, reducing the complexity of valve adjustment.
[0043] In common application scenarios, the first heat exchanger 2 is an air conditioning water heat exchanger, which typically uses a plate heat exchanger. The second heat exchanger 3 is a hot water heat exchanger, which typically uses a shell-and-tube heat exchanger. The third heat exchanger 4 is an outdoor heat exchanger, which typically uses a finned heat exchanger equipped with a fan. When the finned heat exchanger participates in refrigerant circulation, the fan of the finned heat exchanger is turned on. This design, by configuring an air conditioning water heat exchanger, a hot water heat exchanger, and an outdoor heat exchanger, can concentrate cooling, heating, and hot water supply modes into a heat recovery system, resulting in more efficient waste heat recovery and more stable low-temperature operation.
[0044] Specifically, the heat recovery system has at least one of the following operating modes: hot water mode, cooling mode, heating mode, and cooling and heating water mode. The following text details the operating status of the three heat exchangers under different operating modes.
[0045] like Figure 4 As shown, when the heat recovery system is running in hot water mode, the second heat exchanger 3 acts as a condenser, the third heat exchanger 4 acts as an evaporator, the first heat exchanger 2 does not participate in the refrigerant cycle, the exhaust side of the compressor unit 1 is connected to the first end of the second heat exchanger 3, and the main circulation loop flows as follows: compressor unit 1 → second heat exchanger 3 → liquid receiver 5 → economizer 6 → second throttle valve 11 → third heat exchanger 4 → back to compressor unit 1.
[0046] like Figure 5 As shown, when the heat recovery system is operating in cooling mode, the first heat exchanger 2 acts as an evaporator, the third heat exchanger 4 acts as a condenser, the second heat exchanger 3 does not participate in the refrigerant cycle, the exhaust side of the compressor unit 1 is connected to the first end of the third heat exchanger 4, and the main circulation loop flows as follows: compressor unit 1 → third heat exchanger 4 → liquid receiver 5 → economizer 6 → first throttle valve 10 → first heat exchanger 2 → back to compressor unit 1.
[0047] like Figure 6 As shown, when the heat recovery system is in heating mode, the first heat exchanger 2 acts as a condenser, the third heat exchanger 4 acts as an evaporator, the second heat exchanger 3 does not participate in the refrigerant cycle, the exhaust side of the compressor unit 1 is connected to the first end of the first heat exchanger 2, and the main circulation loop flows as follows: compressor unit 1 → first heat exchanger 2 → liquid receiver 5 → economizer 6 → second throttle valve 11 → third heat exchanger 4 → back to compressor unit 1.
[0048] like Figure 7 As shown, when the heat recovery system operates in the cooling and heating water mode, the first heat exchanger 2 acts as an evaporator, the second heat exchanger 3 acts as a condenser, the third heat exchanger 4 does not participate in the refrigerant cycle, the exhaust side of the compressor unit 1 is connected to the first end of the first heat exchanger 2, and the main circulation loop flows as follows: compressor unit 1 → second heat exchanger 3 → liquid receiver 5 → economizer 6 → first throttle valve 10 → first heat exchanger 2 → back to compressor unit 1.
[0049] The heat recovery system utilizes three heat exchangers working in tandem to flexibly switch operating modes under different conditions, maximizing waste heat recovery. For example, in cooling mode, the refrigerant absorbs heat in the evaporator (air conditioning water heat exchanger) to achieve cooling; in heating mode, the high-temperature refrigerant discharged from compressor unit 1 releases heat in the condenser (air conditioning water heat exchanger) to achieve heating; in hot water mode, the high-temperature refrigerant discharged from compressor unit 1 is used to heat domestic water in the hot water heat exchanger, improving hot water supply efficiency; in the combined operating mode (cooling + hot water), the heat from the recovered refrigerant is used to heat domestic hot water, achieving cascaded energy utilization and improving the energy efficiency of the heat recovery system.
[0050] It should be noted that in the preferred embodiment, the auxiliary throttle valve 12 is closed when the heat recovery system is operating in hot water mode. That is, the auxiliary throttle valve 12 can be opened in cooling mode, heating mode, and cooling / heating water mode to introduce some refrigerant into compressor unit 1 for gas replenishment. However, in hot water mode, the auxiliary throttle valve 12 remains closed. This design is because in hot water mode, the system prioritizes meeting the demand for domestic hot water heating. Closing the auxiliary throttle valve 12 at this time avoids diverting refrigerant for gas replenishment, ensuring that more heat is used to heat the water tank, thus improving heating efficiency. Furthermore, in hot water mode, the load on compressor unit 1 is usually low (water temperature demand is stable), and increasing enthalpy might actually increase unnecessary energy consumption; closing it saves more electricity.
[0051] like Figure 1 As shown, in some embodiments of this utility model, the heat recovery system includes the four working modes mentioned above. To achieve more accurate and reliable switching to different working modes, the compressor unit 1 is connected to three heat exchangers through two four-way valves; the D end of the first four-way valve 13 is connected to the exhaust side of the compressor unit 1, the E end is connected to the first end of the first heat exchanger 2, the S end is connected to the suction side of the compressor unit 1, and the C end is connected to the D end of the second four-way valve 14; the C end of the second four-way valve 14 is connected to the first end of the third heat exchanger 4, the E end is connected to the first end of the second heat exchanger 3, and the S end is connected to the suction side of the compressor unit 1.
[0052] Specifically, the switching states of the four-way valve under different operating modes are as follows:
[0053] When the heat recovery system is running in hot water mode, the D end of the first four-way valve 13 is connected to the C end and the E end is connected to the S end, and the D end of the second four-way valve 14 is connected to the E end and the C end is connected to the S end.
[0054] When the heat recovery system is operating in cooling mode, the D end of the first four-way valve 13 is connected to the C end and the E end is connected to the S end, and the D end of the second four-way valve 14 is connected to the C end and the E end is connected to the S end.
[0055] When the heat recovery system is in heating mode, the D end of the first four-way valve 13 is connected to the E end and the C end is connected to the S end, and the D end of the second four-way valve 14 is connected to the C end and the E end is connected to the S end.
[0056] When the heat recovery system is operating in cooling and heating water mode, the D end of the first four-way valve 13 is connected to the C end and the E end is connected to the S end, and the D end of the second four-way valve 14 is connected to the E end and the C end is connected to the S end.
[0057] like Figure 2As shown, in some embodiments of this utility model, the heat recovery system is a variable frequency heat pump system. The IPM module 15 of the heat recovery system is equipped with a heat dissipation pipe, which is connected in series with the inlet pipe of the liquid receiver 5 so that all refrigerant sent to the liquid receiver 5 passes through the heat dissipation pipe. This design places the heat dissipation pipe of the IPM module 15 on the inlet side of the liquid receiver 5, ensuring that the liquid refrigerant cooled by the condenser always passes through the heat dissipation pipe, stably and reliably dissipating heat from the IPM module 15 and improving the safety of the heat recovery system.
[0058] To facilitate understanding, the operating status under different working modes will be explained using application examples of this utility model.
[0059] Hot water mode
[0060] like Figure 4 As shown, when the heat recovery system is turned on, it enters the hot water mode. The first four-way valve 13 is de-energized (D end connects to C end, E end connects to S end), the second four-way valve 14 is energized (D end connects to E end, C end connects to S end), the second throttle valve 11 enters the working mode, the compressor unit 1 is turned on, and the first throttle valve 10 and the auxiliary throttle valve 12 remain closed.
[0061] After the heat recovery system is running stably, the high-temperature and high-pressure refrigerant vapor is discharged from the compressor unit 1 and flows through the DC channel of the first four-way valve 13 and the DE channel of the second four-way valve 14. It then enters the second heat exchanger 3 for heat exchange, transferring heat to the water side. After being subcooled into high-pressure liquid refrigerant, it flows out from the second heat exchanger 3, passes through the first one-way valve 7 to dissipate heat for the IPM module 15, and then enters the liquid receiver 5. It is then sent to the upstream of the second throttle valve 11 by the main line of the economizer 6. After being throttled at the second throttle valve 11, it enters the third heat exchanger 4 as a low-temperature and low-pressure two-phase refrigerant to absorb heat from the air. After being vaporized into low-temperature and low-pressure refrigerant vapor, it flows out and enters the gas-liquid separator 16 through the CS channel of the second four-way valve 14. Finally, it returns to the compressor unit 1 from the gas-liquid separator 16.
[0062] Cooling mode
[0063] like Figure 5 As shown, when the heat recovery system is turned on, it enters the cooling mode. The first four-way valve 13 is de-energized (D end connects to C end, E end connects to S end) and the second four-way valve 14 is de-energized (D end connects to C end, E end connects to S end). The first throttle valve 10 and the auxiliary throttle valve 12 enter the working mode, the compressor is turned on, and the second throttle valve 11 remains closed.
[0064] After the heat recovery system is running stably, the high-temperature and high-pressure refrigerant vapor is discharged from the compressor unit 1, flows through the DC channel of the first four-way valve 13 and the DC channel of the second four-way valve 14, and enters the third heat exchanger 4 for heat exchange. After being subcooled into high-pressure liquid refrigerant, it flows out and passes through the third one-way valve 9 to dissipate heat to the IPM module 15. Then, it is subcooled by the economizer 6 and divided into two paths - the main path and the enthalpy-increasing branch path.
[0065] The refrigerant from the main economizer circuit is throttled at the first expansion valve 10, then enters the first heat exchanger 2 as a low-temperature, low-pressure two-phase refrigerant to absorb heat from the air conditioning water side. After vaporizing into low-temperature, low-pressure refrigerant vapor, it flows out and enters the gas-liquid separator 16 through the ES channel of the first four-way valve 13, and then returns to the compressor unit 1 from the gas-liquid separator 16. The refrigerant from the enthalpy-increasing branch circuit is throttled at the auxiliary circuit expansion valve 12 and then enters the economizer 6 to evaporate into a relatively low-temperature gaseous refrigerant, which then enters the gas supply port of the compressor unit 1.
[0066] The water pump on the water side of the first heat exchanger 2 starts, driving the cold water in the first heat exchanger 2 to the terminal for users to use for cooling.
[0067] Heating mode
[0068] like Figure 6 As shown, when the heat recovery system is turned on and enters the heating mode, the first four-way valve 13 is energized (D end connects to E end, C end connects to S end), the second four-way valve 14 is de-energized (D end connects to C end, E end connects to S end), the second throttle valve 11 and the auxiliary throttle valve 12 enter the working mode, the compressor unit 1 is turned on, and the first throttle valve 10 remains closed.
[0069] After the heat recovery system is running stably, the high-temperature and high-pressure refrigerant vapor is discharged from the compressor unit 1, flows through the DE channel of the first four-way valve 13, enters the first heat exchanger 2 for heat exchange, and transfers heat to the water side. After being subcooled into high-pressure liquid refrigerant, it flows out and passes through the second one-way valve 8 to dissipate heat to the IPM module 15. Then, it is subcooled by the economizer 6 and divided into two paths - the main path and the enthalpy-increasing branch path.
[0070] The refrigerant from the main circuit is throttled at the second throttle valve 11 and then enters the third heat exchanger 4 as a low-temperature, low-pressure two-phase refrigerant to absorb heat from the air. After vaporizing into low-temperature, low-pressure refrigerant vapor, it flows out and enters the gas-liquid separator 16 through the CD channel of the second four-way valve 14 and the CS channel of the first four-way valve 13. Then, it returns to the compressor unit 1 from the gas-liquid separator 16. The refrigerant from the enthalpy-increasing branch is throttled at the auxiliary circuit throttle valve 12 and then enters the economizer 6 to evaporate into a relatively low-temperature gaseous refrigerant, which then enters the gas supply port of the compressor unit 1.
[0071] The water pump on the water side of the first heat exchanger 2 is started, driving the hot water in the first heat exchanger 2 to the terminal for users to use for heating.
[0072] Cooling and heating water modes
[0073] like Figure 7 As shown, when the heat recovery system is turned on, it enters the cooling and heating water supply mode. The first four-way valve 13 is de-energized (D end connects to C end, E end connects to S end), the second four-way valve 14 is energized (D end connects to E end, C end connects to S end), the first throttle valve 10 and the auxiliary throttle valve 12 enter the working mode, the compressor unit 1 is turned on, and the second throttle valve 11 remains closed.
[0074] After the heat recovery system is running stably, the high-temperature and high-pressure refrigerant vapor is discharged from the compressor unit 1 and flows through the DC channel of the first four-way valve 13 and the DE channel of the second four-way valve 14. It then enters the second heat exchanger 3 for heat exchange, transferring heat to the water side. After being subcooled into high-pressure liquid refrigerant, it flows out from the second heat exchanger 3. After passing through the first one-way valve 7 to dissipate heat to the IPM module 15, it is then subcooled by the economizer 6 and divided into two paths—the main path and the enthalpy-increasing branch path.
[0075] In the economizer main circuit, the refrigerant is throttled at the first throttle valve 10 and enters the first heat exchanger 2 as a low-temperature, low-pressure two-phase refrigerant to absorb heat from the air conditioning water side. After vaporizing into low-temperature, low-pressure refrigerant vapor, it flows out and enters the gas-liquid separator through the ES channel of the first four-way valve 13, and then returns to the compressor unit 1 through the gas-liquid separator 16. The refrigerant in the enthalpy-increasing branch circuit is throttled at the auxiliary circuit throttle valve 12 and enters the economizer 6 to evaporate into a relatively low-temperature gaseous refrigerant, which then enters the gas injection port of the compressor unit 1.
[0076] The water pump on the water side of the first heat exchanger 2 starts, driving the cold water in the first heat exchanger 2 to the terminal for users to use for cooling.
[0077] like Figure 1 As shown, in order to make the heat recovery system operate more stably and for longer, a filter 17 is installed at the first and / or second end of each heat exchanger. The filter 17 is used to intercept impurities in the refrigerant circulation loop, prevent clogging of the expansion valve or wear of the compressor, reduce maintenance frequency, and extend the system life.
[0078] The compressor unit 1 has an oil separator 18 on its discharge side. The outlet pipe of the oil separator 18 is connected in series with an oil return valve 19 to the suction side of the compressor unit 1. The oil return valve 19 opens when the compressor unit 1 is started. The oil separator 18 efficiently captures refrigerant oil in the discharge, preventing lubricating oil from entering the circulation system and causing the compressor to seize due to oil shortage. The oil return valve 19 controls the return of lubricating oil to the suction side of the compressor, ensuring continuous and reliable lubrication and extending the compressor's lifespan.
[0079] likeFigure 3 As shown, in a preferred embodiment of this invention, compressor unit 1 includes two compressors connected in parallel. The parallel operation of the two compressors allows for control of their operating status based on the load. For example, only one compressor can be started under low load conditions, while both compressors operate simultaneously under high load / low temperature conditions, sharing the compression ratio to avoid overloading of a single compressor. Through the dual compressors and enthalpy-enhancing gas injection design, the capacity and energy efficiency of the heat recovery system are significantly improved, enabling the system to operate under different environmental conditions, especially low-temperature environments, thus expanding its applicability.
[0080] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments according to this utility model. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., in the apparatus and methods shown in the specification and drawings can be implemented in any order unless a specific express order is specified, and as long as the output of the preceding process is not used in the subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.
[0081] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.
[0082] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A low-temperature enthalpy-increasing heat recovery system, comprising: The system comprises a compressor unit, three heat exchangers, and a liquid receiver. The compressor unit can be connected to any two of the heat exchangers to form a refrigerant circulation loop. The inlet pipe of the liquid receiver is connected to the condenser outlet side of the refrigerant circulation loop. The liquid receiver's outlet pipe is connected to an economizer. The main circuit of the economizer is connected back to the refrigerant circulation loop. The enthalpy-increasing branch of the economizer is connected in series with an auxiliary circuit throttle valve to the compressor unit's gas injection port.
2. The low-temperature enthalpy-increasing heat recovery system according to claim 1, characterized in that, The three heat exchangers are the first heat exchanger, the second heat exchanger, and the third heat exchanger. The exhaust side of the compressor unit can be switched to connect to the first end of any heat exchanger, and the second end of each heat exchanger is connected to the inlet pipe of the liquid receiver through a valve. The second end of the first heat exchanger is connected to the second end of the third heat exchanger through a throttling pipe. The throttling pipe is connected in series with a first throttling valve and a second throttling valve. The main circuit of the economizer is connected between the first throttling valve and the second throttling valve.
3. The low-temperature enthalpy-increasing heat recovery system according to claim 2, characterized in that, The first heat exchanger is an air conditioning water heat exchanger, the second heat exchanger is a hot water heat exchanger, and the third heat exchanger is an outdoor heat exchanger.
4. The low-temperature enthalpy-increasing heat recovery system according to claim 3, characterized in that, The heat recovery system operates in at least one of the following modes: hot water mode, cooling mode, heating mode, and cooling and heating water mode. When the heat recovery system is operating in hot water mode, the second heat exchanger acts as a condenser, the third heat exchanger acts as an evaporator, and the first heat exchanger does not participate in the refrigerant cycle. And / or when the heat recovery system is operating in cooling mode, the first heat exchanger acts as an evaporator, the third heat exchanger acts as a condenser, and the second heat exchanger does not participate in the refrigerant cycle; And / or when the heat recovery system is operating in heating mode, the first heat exchanger acts as a condenser, the third heat exchanger acts as an evaporator, and the second heat exchanger does not participate in the refrigerant cycle; And / or when the heat recovery system is operating in cooling and heating water mode, the third heat exchanger acts as an evaporator, the second heat exchanger acts as a condenser, and the first heat exchanger does not participate in the refrigerant cycle.
5. The low-temperature enthalpy-increasing heat recovery system according to claim 4, characterized in that, The auxiliary throttling valve is closed when the heat recovery system is operating in the hot water mode.
6. The low-temperature enthalpy-increasing heat recovery system according to claim 2, characterized in that, The compressor unit is connected to the three heat exchangers via two four-way valves; The first four-way valve has its D end connected to the exhaust side of the compressor unit, its E end connected to the first end of the first heat exchanger, its S end connected to the suction side of the compressor unit, and its C end connected to the D end of the second four-way valve. The C end of the second four-way valve is connected to the first end of the third heat exchanger, the E end is connected to the first end of the second heat exchanger, and the S end is connected to the suction side of the compressor unit.
7. The low-temperature enthalpy-increasing heat recovery system according to claim 2, characterized in that, The valve is a one-way valve, which only allows refrigerant to flow to the liquid receiver.
8. The low-temperature enthalpy-increasing heat recovery system according to claim 1, characterized in that, The heat recovery system is a variable frequency heat pump system. The IPM module of the heat recovery system is equipped with a heat dissipation pipe. The heat dissipation pipe is connected in series with the inlet pipe of the liquid receiver so that all the refrigerant sent to the liquid receiver passes through the heat dissipation pipe.
9. The low-temperature enthalpy-increasing heat recovery system according to claim 1, characterized in that, Each of the heat exchangers is equipped with a filter at its first and / or second end.
10. The low-temperature enthalpy-increasing heat recovery system according to any one of claims 1 to 9, characterized in that, The compressor unit comprises two compressors connected in parallel.