Heat pump circulation system and heat pump circulation control method

Abstract

The invention discloses a heat pump circulation system and a heat pump circulation control method. The heat pump circulating system comprises a compressor, a first condenser, a second condenser, an evaporator, an expansion valve, a first switch valve, a second switch valve and a third switch valve, and the compressor communicates with the first condenser through a first branch pipeline of a first pipeline and communicates with the second condenser through a second branch pipeline. The first condenser and the second condenser are connected in series through the second pipeline, the first switch valve is arranged on the first branch pipeline, the second switch valve is arranged on the second branch pipeline, and the third switch valve is arranged on the second pipeline. By controlling the on-off of the first switch valve, the second switch valve and the third switch valve, the heat pump circulation system has a primary heating mode in which only the second condenser participates in work and a secondary heating mode in which the first condenser and the second condenser work simultaneously, so that the heat exchange efficiency of the condensers is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump cycles, and particularly to a heat pump cycle system and a heat pump cycle control method. Background Art

[0002] In a traditional heat pump cycle system, it mainly consists of four major components: a compressor, a condenser, a throttle valve, and an evaporator, and its structure is relatively simple. The exhaust temperature of the compressor is generally relatively high. In the condenser, the refrigerant is cooled by flowing water. Since the heat exchange temperature difference between the refrigerant and water is relatively large, especially at the hot end of the condenser, the heat exchange temperature difference is often above 20°C, and even above 30°C, resulting in a relatively low heat exchange efficiency of the condenser.

[0003] Therefore, how to propose a heat pump cycle system that can improve the heat exchange efficiency of the condenser is a technical problem that urgently needs to be solved at present. Summary of the Invention

[0004] The first object of the present invention is to provide a heat pump cycle system, which has two modes: a primary heating mode and a secondary heating mode, and is conducive to improving the heat exchange efficiency of the condenser.

[0005] The second object of the present invention is to provide a heat pump cycle control method, which can select different heating modes according to the exhaust temperature of the compressor, and is conducive to improving the heat exchange efficiency of the condenser.

[0006] The third object of the present invention is to provide a heat pump cycle control method, which can select different heating modes according to the inlet temperature of the water to be heated, and is conducive to improving the heat exchange efficiency of the condenser.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] A heat pump cycle system, comprising: a compressor and a first pipeline. The first pipeline includes a main pipeline, a first branch pipeline and a second branch pipeline that are connected to each other. The outlet of the compressor is connected to the main pipeline; a first condenser and a second condenser. The outlet of the first condenser and the inlet of the second condenser are connected through a second pipeline. The outlet of the first branch pipeline is connected to the inlet of the first condenser, and the outlet of the second branch pipeline is connected to the inlet of the second condenser; a water inlet pipeline that enables the water to be heated to flow through the second condenser and the first condenser in sequence for heat exchange; an evaporator and an expansion valve. The outlet of the second condenser, the expansion valve, the evaporator and the inlet of the compressor are connected in sequence through pipelines and form an annular passage for the refrigerant to flow with the first pipeline and the second pipeline; a first switching valve, a second switching valve and a third switching valve. The first switching valve is arranged on the first branch pipeline, the second switching valve is arranged on the second branch pipeline, and the third switching valve is arranged on the second pipeline; wherein, the heat pump cycle system has a primary heating mode in which the first switching valve blocks the first branch pipeline, the second switching valve opens the second branch pipeline, and the third switching valve blocks the second pipeline, and a secondary heating mode in which the first switching valve opens the first branch pipeline, the second switching valve blocks the second branch pipeline, and the third switching valve opens the second pipeline.

[0009] Preferably, the outlet of the second branch pipeline is connected to the second pipeline and the connection point is A. The second pipeline includes a first section located on one side of the connection point A and close to the first condenser and a second section located on the other side of the connection point A and close to the second condenser. The third switching valve is arranged on the first section.

[0010] Preferably, the heat exchange area of the first condenser is less than or equal to the heat exchange area of the second condenser.

[0011] Preferably, the water inlet pipeline includes a water inlet section, an intermediate pipe section and a water outlet section. The water inlet section is connected to the water inlet of the second condenser. The intermediate pipe section is connected between the water outlet of the second condenser and the water inlet of the first condenser. The water outlet section is connected to the water outlet of the first condenser. A first water inlet is formed on the water inlet section.

[0012] Preferably, a second water inlet is arranged on the intermediate pipe section. Through the second water inlet, separate water inlet into the first condenser can be realized in the secondary heating mode.

[0013] Preferably, the intermediate pipe section includes a first pipe section located on one side of the second water inlet and close to the first condenser, and a second pipe section located on the other side of the second water inlet and close to the second condenser. A fourth switching valve or a check valve is provided on the second pipe section.

[0014] Preferably, the outlet of the second condenser is communicated with the inlet of the evaporator through a third pipeline, the outlet of the evaporator is communicated with the inlet of the compressor through a fourth pipeline, and an expansion valve is provided on the third pipeline; the heat pump cycle system further includes a regenerator which has a heat flow side passage and a cold flow side passage. The heat flow side passage is connected in series to the third pipeline, the cold flow side passage is connected in series to the fourth pipeline, and the expansion valve is provided between the heat flow side outlet of the regenerator and the evaporator.

[0015] Preferably, the heat pump cycle system further includes a four-way reversing valve. The first valve port of the four-way reversing valve is communicated with the second branch pipeline, the second valve port of the four-way reversing valve is communicated with the inlet of the second condenser, the third valve port of the four-way reversing valve is communicated with the cold flow side outlet of the regenerator, and the fourth valve port of the four-way reversing valve is communicated with the inlet of the compressor;

[0016] Wherein, the heat pump cycle system has a defrosting mode in which the first switching valve blocks the first branch pipeline, the second switching valve opens the second branch pipeline, the third switching valve blocks the second pipeline, and the four-way reversing valve is in a state where the first valve port is communicated with the third valve port and the second valve port is communicated with the fourth valve port.

[0017] A heat pump cycle control method for the above heat pump cycle system, the heat pump cycle control method includes the following steps:

[0018] Obtain the exhaust temperature of the compressor;

[0019] Judge whether the exhaust temperature of the compressor is higher than a first temperature value;

[0020] If so, control the first switching valve and the third switching valve to open and the second switching valve to close, so that the refrigerant flowing out of the compressor flows through the first condenser and the second condenser in sequence, and control the water to be heated to flow through the second condenser and the first condenser in sequence to exchange heat with the refrigerant, so that the heat pump cycle system is in a secondary heating mode;

[0021] If not, control the first switching valve and the third switching valve to close and the second switching valve to open, so that the refrigerant flowing out of the compressor directly flows through the second condenser, and control the water to be heated to flow through the second condenser to exchange heat with the refrigerant, so that the heat pump cycle system is in a primary heating mode.

[0022] Preferably, the heat pump cycle control method further includes the following steps:

[0023] Determine whether the coil of the evaporator needs defrosting;

[0024] If so, control the first switching valve to close, the third switching valve to close, the second switching valve to open, and control the first port and the third port of the four-way reversing valve to conduct, and the second port and the fourth port to conduct, so that the refrigerant flowing out of the compressor sequentially flows through the first flow path connecting the first port and the third port of the four-way reversing valve, the cold-side passage of the regenerator, the evaporator, the hot-side passage of the regenerator, and the second flow path connecting the second port and the fourth port of the four-way reversing valve and then returns to the compressor.

[0025] A heat pump cycle control method for the above heat pump cycle system, the heat pump cycle control method includes the following steps:

[0026] Obtain the water inlet temperature at the water inlet pipeline;

[0027] Determine whether the water inlet temperature is lower than the second temperature value;

[0028] If so, control the first switching valve and the third switching valve to open, the second switching valve to close, so that the refrigerant flowing out of the compressor sequentially flows through the first condenser and the second condenser, and control the water to be heated to sequentially flow through the second condenser and the first condenser to exchange heat with the refrigerant, so that the heat pump cycle system is in the secondary heating mode;

[0029] If not, control the first switching valve and the third switching valve to close, the second switching valve to open, so that the refrigerant flowing out of the compressor directly flows through the second condenser, and control the water to be heated to flow through the second condenser to exchange heat with the refrigerant, so that the heat pump cycle system is in the primary heating mode.

[0030] Preferably, the heat pump cycle control method further includes the following steps:

[0031] Determine whether the coil of the evaporator needs defrosting;

[0032] If so, control the first switching valve to close, the third switching valve to close, and the second switching valve to open, and control the first port and the third port of the four-way reversing valve to conduct, and the second port and the fourth port to conduct, so that the refrigerant flowing out of the compressor sequentially flows through the first flow path connecting the first port and the third port of the four-way reversing valve, the cold-side passage of the regenerator, the evaporator, the hot-side passage of the regenerator, and the second flow path connecting the second port and the fourth port of the four-way reversing valve and then returns to the compressor.

[0033] Advantages of the present invention:

[0034] The heat pump cycle system provided by the present invention includes a compressor, a first condenser, a second condenser, an evaporator, an expansion valve, a first switching valve, a second switching valve, and a third switching valve. The compressor is connected to the first condenser through the first branch pipeline of the first pipeline and to the second condenser through the second branch pipeline. The first condenser and the second condenser are connected in series through the second pipeline. The first switching valve is arranged on the first branch pipeline, the second switching valve is arranged on the second branch pipeline, and the third switching valve is arranged on the second pipeline. By controlling the on-off of the first switching valve, the second switching valve, and the third switching valve, the heat pump cycle system has a primary heating mode in which only the second condenser participates in work and a secondary heating mode in which the first condenser and the second condenser work simultaneously, thereby improving the heat exchange efficiency of the condenser. Description of the drawings

[0035] Figure 1 is a schematic diagram of the heat pump cycle system provided by the embodiment of the present invention;

[0036] Figure 2 is a schematic diagram of the heat pump cycle system provided by the embodiment of the present invention in the primary heating mode;

[0037] Figure 3 is a pressure-enthalpy diagram of the heat pump cycle system provided by the embodiment of the present invention in the primary heating mode;

[0038] Figure 4 is a schematic diagram of the heat pump cycle system provided by the embodiment of the present invention in the secondary heating mode;

[0039] Figure 5 is a pressure-enthalpy diagram of the heat pump cycle system provided by the embodiment of the present invention in the secondary heating mode;

[0040] Figure 6 is a schematic diagram of the heat pump cycle system provided by the embodiment of the present invention in the defrosting mode;

[0041] Figure 7 is a schematic diagram of the heat pump cycle system provided by the embodiment of the present invention when the water inlet pipeline has two water inlets;

[0042] Figure 8 is a flowchart of a heat pump cycle control method provided by an embodiment of the present invention;

[0043] Figure 9 is a flowchart of another heat pump cycle control method provided by an embodiment of the present invention.

[0044] In the figure:

[0045] 1. Compressor; 2. First pipeline; 201. Main pipeline; 202. First branch pipeline; 203. Second branch pipeline; 3. First condenser; 4. Second condenser; 5. Second pipeline; 6. Water inlet pipeline; 601. First water inlet; 602. Second water inlet; 7. Evaporator; 8. Third pipeline; 9. Fourth pipeline; 10. Expansion valve; 11. First switching valve; 12. Second switching valve; 13. Third switching valve; 14. Regenerator; 15. Four-way reversing valve. Detailed implementation manners

[0046] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0047] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0048] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0049] The present invention discloses a heat pump cycle system, as Figures 1 to 7As shown in the figure, the heat pump cycle system includes a compressor 1, a first condenser 3, a second condenser 4, a water inlet pipeline 6, an evaporator 7, a first switching valve 11, a second switching valve 12, a third switching valve 13, a first pipeline 2, a second pipeline 5, a third pipeline 8, and a fourth pipeline 9. Specifically, the first pipeline 2 is a three-way pipeline. The first pipeline 2 includes a main pipeline 201, a first branch pipeline 202, and a second branch pipeline 203 that are interconnected. The first pipeline 2 includes a first port located at the main pipeline 201, a second port located at the first branch pipeline 202, and a third port located at the second branch pipeline 203. The outlet of the compressor 1 is connected to the first port of the main pipeline 201. The outlet of the first condenser 3 and the inlet of the second condenser 4 are connected through the second pipeline 5. The outlet of the first branch pipeline 202 (i.e., the second port) is connected to the inlet of the first condenser 3, and the outlet of the second branch pipeline 203 (i.e., the third port) is connected to the inlet of the second condenser 4. The outlet of the second condenser 4 is connected to the inlet of the evaporator 7 through the third pipeline 8, and the outlet of the evaporator 7 is connected to the inlet of the compressor 1 through the fourth pipeline 9. An expansion valve 10 is provided on the third pipeline 8. The first pipeline 2, the second pipeline 5, the third pipeline 8, and the fourth pipeline 9 form an annular passage for the refrigerant to flow through.

[0050] Among them, the water inlet pipeline 6 enables the water to be heated to flow through the second condenser 4 and the first condenser 3 in sequence for heat exchange. The first switching valve 11 is provided on the first branch pipeline 202 and is used to control the on-off of the first branch pipeline 202. The second switching valve 12 is provided on the second branch pipeline 203 and is used to control the on-off of the second branch pipeline 203. The third switching valve 13 is provided on the second pipeline 5 and is used to control the on-off of the second pipeline 5. It should be noted that when the first switching valve 11 is opened, the first branch pipeline 202 is conducted; when the first switching valve 11 is closed, the first branch pipeline 202 is blocked. When the second switching valve 12 is opened, the second branch pipeline 203 is conducted; when the second switching valve 12 is closed, the second branch pipeline 203 is blocked. When the third switching valve 13 is opened, the second pipeline 5 is conducted; when the third switching valve 13 is closed, the second pipeline 5 is blocked.

[0051] The heat pump cycle system has a primary heating mode and a secondary heating mode. When the heat pump cycle system is in the primary heating mode, the first switching valve 11 is closed to block the first branch pipeline 202, the second switching valve 12 is opened to conduct the second branch pipeline 203, and the third switching valve 13 is closed to block the second pipeline 5. When the heat pump cycle system is in the secondary heating mode, the first switching valve 11 is opened to conduct the first branch pipeline 202, the second switching valve 12 is closed to block the second branch pipeline 203, and the third switching valve 13 is opened to conduct the second pipeline 5.

[0052] The heat pump cycle system can switch between the primary heating mode and the secondary heating mode by controlling the on-off states of the first switching valve 11, the second switching valve 12, and the third switching valve 13. The heat pump cycle system selects different heating modes according to the exhaust gas temperature range of the compressor 1 and / or the inlet water temperature range of the water to be heated, which can always achieve better heat exchange temperature difference matching in the condenser, thereby obtaining better heat exchange efficiency.

[0053] To obtain the exhaust gas temperature of the compressor 1, a first temperature detection mechanism (not shown in the figure) is provided at the exhaust port of the compressor 1, and the temperature of the exhaust port of the compressor 1 can be obtained by using the first temperature detection mechanism. Optionally, the first temperature detection mechanism is a temperature sensor. In some embodiments, when the first temperature detection mechanism detects that the exhaust gas temperature of the compressor 1 is higher than or equal to 85 °C, the heat pump cycle system switches to the secondary heating mode by controlling the on-off states of the first switching valve 11, the second switching valve 12, and the third switching valve 13; when the first temperature detection mechanism detects that the exhaust gas temperature of the compressor 1 is lower than 85 °C, the heat pump cycle system switches to the primary heating mode by controlling the on-off states of the first switching valve 11, the second switching valve 12, and the third switching valve 13.

[0054] To obtain the inlet water temperature of the water to be heated, a second temperature detection mechanism (not shown in the figure) is provided at the inlet of the water inlet pipe 6, and the inlet water temperature of the water to be heated can be obtained by using the second temperature detection mechanism. Optionally, the second temperature detection mechanism is a temperature sensor. In some embodiments, when the second temperature detection mechanism detects that the exhaust gas temperature of the compressor 1 is lower than or equal to 10 °C, the heat pump cycle system switches to the secondary heating mode by controlling the on-off states of the first switching valve 11, the second switching valve 12, and the third switching valve 13; when the second temperature detection mechanism detects that the exhaust gas temperature of the compressor 1 is higher than 10 °C, the heat pump cycle system switches to the primary heating mode by controlling the on-off states of the first switching valve 11, the second switching valve 12, and the third switching valve 13.

[0055] In some embodiments, the outlet of the second branch pipe 203 is directly connected to the inlet of the second condenser 4. In some parallel embodiments, the outlet of the second branch pipe 203 is connected to the second pipe 5, and the connection point is A (as Figure 1 shown), the second pipe 5 includes a first section on one side of the connection point A and close to the first condenser 3 and a second section on the other side of the connection point A and close to the second condenser 4, and the third switching valve 13 is provided on the first section. Such a setting makes the connection between the second branch pipe 203 and the second pipe 5 more convenient and the assembly more efficient.

[0056] In some embodiments, the heat exchange area of the first condenser 3 is less than or equal to that of the second condenser 4. When the heat exchange area of the first condenser 3 is less than that of the second condenser 4, the heat load that the first condenser 3 can bear is also smaller. The different heat exchange areas of the first condenser 3 and the second condenser 4 enable the heat pump cycle system to better match the heat exchange temperature difference, thereby obtaining better heat exchange efficiency.

[0057] As Figure 7 shown, in order to connect the water inlet pipe 6 with the first condenser 3 and the second condenser 4, in some embodiments, the water inlet pipe 6 includes a water inlet section, an intermediate pipe section, and a water outlet section. The water inlet section is connected to the water inlet of the second condenser 4. The intermediate pipe section is connected between the water outlet of the second condenser 4 and the water inlet of the first condenser 3. The water outlet section is connected to the water outlet of the first condenser 3. A first water inlet 601 is formed on the water inlet section.

[0058] Through the first water inlet 601, water to be heated can be injected into the water inlet section. The water enters the second condenser 4 through the water inlet section. During the process of flowing through the second condenser 4, the water to be heated undergoes a first heat exchange with the refrigerant flowing through the second condenser 4. In the secondary heating mode, the water flowing out of the second condenser 4 flows into the first condenser 3 through the intermediate pipe. During the process of flowing through the first condenser 3, the water to be heated undergoes a second heat exchange with the refrigerant flowing through the first condenser 3. The water that has been secondarily heated flows out through the water outlet section.

[0059] Of course, in the secondary heating mode, the primary heating of water can also be achieved by changing the water inlet position. As Figure 7 shown, in some embodiments, a second water inlet 602 is provided on the intermediate pipe section. Through the second water inlet 602, separate water inlet into the first condenser 3 can be achieved in the secondary heating mode. Such a setting makes the heating of water more flexible. Especially when the heat exchange areas of the first condenser 3 and the second condenser 4 are different, users can more flexibly select to heat water separately using only the second condenser 4 in the primary heating mode, heat water using both the first condenser 3 and the second condenser 4 simultaneously in the secondary heating mode, and heat water using only the first condenser 3 in the secondary heating mode.

[0060] To prevent the water entering the intermediate pipe section from the second water inlet 602 from flowing back to the second condenser 4, in some embodiments, the intermediate pipe section includes a first pipe section located on one side of the second water inlet 602 and close to the first condenser 3, and a second pipe section located on the other side of the second water inlet 602 and close to the second condenser 4. A fourth switching valve (not shown in the figure) or a check valve (not shown in the figure) is provided on the second pipe section. By providing the fourth switching valve and the check valve, the water can be prevented from flowing back to the second condenser 4. Optionally, the above-mentioned first switching valve 11, second switching valve 12, third switching valve 13, and fourth switching valve are all solenoid valves.

[0061] In the actual application of this heat pump cycle system, due to the change of the ambient temperature and the operating characteristics of different refrigerants, the operating conditions of the evaporator 7 change, and the operating conditions of the compressor 1 also change. To ensure the superheat of the suction of the compressor 1, in the prior art, it is generally achieved by adjusting the opening degree of the electronic expansion valve. However, only adjusting the opening degree of the electronic expansion valve will cause the heat pump cycle system not to always be in a more suitable operating condition, and the system operating performance is poor.

[0062] To ensure the superheat degree of the refrigerant at the suction port of the compressor 1, in the embodiment of the present application, the heat pump cycle system further includes a regenerator 14. The regenerator 14 has a heat flow side passage and a cold flow side passage. The heat flow side passage is connected in series to the third pipeline 8, and the cold flow side passage is connected in series to the fourth pipeline 9. And the expansion valve 10 is arranged between the heat flow side outlet of the regenerator 14 and the evaporator 7. Optionally, the expansion valve 10 is an electronic expansion valve.

[0063] The heat regeneration effect of the regenerator 14 further increases the subcooling degree of the refrigerant at the outlet of the second condenser 4, while ensuring the superheat degree of the refrigerant at the suction port of the compressor 1, avoiding the occurrence of liquid carrying during suction, and improving the reliability of the system. At the same time, the addition of the regenerator 14 reduces the control action of the expansion valve 10 on the suction superheat degree, and reduces the fluctuation during the operation of the heat pump cycle system. And, the refrigerant is further heated after leaving the evaporator 7 through the regenerator 14. In addition to ensuring the superheat degree at the suction inlet of the compressor 1, the temperature of the refrigerant at the outlet of the second condenser 4 is further cooled, and the subcooling degree of the refrigerant before the expansion valve 10 is increased.

[0064] Further, as Figure 1 shown, in some embodiments, the heat pump cycle system further includes a four-way reversing valve 15. Optionally, the four-way reversing valve 15 is a four-way electromagnetic reversing valve. The first valve port of the four-way reversing valve 15 is communicated with the second branch pipeline 203, the second valve port of the four-way reversing valve 15 is communicated with the inlet of the second condenser 4, the third valve port of the four-way reversing valve 15 is communicated with the cold flow side outlet of the regenerator 14, and the fourth valve port of the four-way reversing valve 15 is communicated with the inlet of the compressor 1. As Figure 6As shown, the heat pump cycle system also has a defrosting mode. When the heat pump cycle system is in the defrosting mode, the first switching valve 11 is closed to block the first branch pipeline 202, the second switching valve 12 is opened to open the second branch pipeline 203, the third switching valve 13 is closed to block the second pipeline 5, and the first valve port of the four-way reversing valve 15 is communicated with the third valve port, and the second valve port is communicated with the fourth valve port. In this way, the heat pump cycle system can defrost the coil of the evaporator 7, avoiding the long-term accumulation of frost on the coil of the evaporator 7 and affecting its performance. It should be noted that as Figure 2 and Figure 4 shown, when the heat pump cycle system is in the primary heating mode and the secondary heating mode, the first valve port of the four-way reversing valve 15 is communicated with the second valve port, and the third valve port is communicated with the fourth valve port.

[0065] As Figure 3 shown is the pressure-enthalpy (p-h) diagram of the heat pump cycle system in the primary heating mode.

[0066] The specific working process of the primary heating mode is as follows: The refrigerant is compressed by the compressor 1 and becomes a superheated gas in a high-temperature and high-pressure state ( Figure 3 point 2 in), and then enters the heat flow side of the second condenser 4, where it is fully cooled and condensed. At the outlet of the heat flow side of the second condenser 4, the refrigerant becomes a saturated liquid or a liquid with a certain degree of subcooling. After the refrigerant leaves the second condenser 4, it enters the regenerator 14, where it is further heated by the low-temperature and low-pressure refrigerant flowing back from the evaporator 7. The temperature of the high-pressure refrigerant leaving the heat flow side of the regenerator 14 is further reduced, and the degree of subcooling increases. The liquid-phase refrigerant with sufficient subcooling enters the expansion valve 10, where it is throttled to reduce the temperature and pressure. At the outlet of the expansion valve 10, the refrigerant becomes a gas-liquid two-phase state with a low temperature, low pressure, and a certain dryness. This refrigerant then enters the cold flow side of the evaporator 7 to absorb heat and evaporate. The temperature of the refrigerant rises, and the dryness increases. At the outlet of the evaporator 7, the state of the refrigerant is a saturated state or a gas-liquid two-phase state with a large dryness. This refrigerant then enters the cold flow side of the regenerator 14 to absorb the heat of the high-pressure refrigerant leaving the second condenser 4, and the temperature rises, becoming a superheated gas with a certain degree of superheat. Finally, this refrigerant enters the suction inlet of the compressor 1 and is compressed and pressurized in the compressor 1 to complete a complete heat pump cycle.

[0067] When the exhaust temperature of the compressor 1 is relatively low and lower than the set monitoring value, or the inlet temperature of the water to be heated is relatively high and exceeds the set monitoring value, the control system is in the primary heating mode. The refrigerant leaving the compressor 1 can obtain a suitable heat exchange temperature match only by passing through the second condenser 4, and has a certain degree of subcooling at the outlet of the heat flow side of the second condenser 4.

[0068] As Figure 5The figure shows the pressure-enthalpy (p-h) diagram of the heat pump cycle system in the secondary heating mode.

[0069] The specific working process of the secondary heating mode is as follows: After being compressed by the compressor 1, the refrigerant becomes a superheated gas at high temperature and high pressure ( Figure 5 point 2 in the figure), and then enters the heat flow side of the first condenser 3, where it is initially cooled and its temperature decreases. At the outlet of the heat flow side of the first condenser 3, the refrigerant is in a gas-liquid two-phase state close to the saturated gas state or with a large dryness. Subsequently, the refrigerant enters the heat flow side of the second condenser 4 and is fully cooled and condensed. At the outlet of the heat flow side of the second condenser 4, the refrigerant becomes a saturated liquid or a liquid with a certain degree of subcooling. After leaving the second condenser 4, the refrigerant enters the regenerator 14, where it is further heated by the low-temperature and low-pressure refrigerant flowing back from the evaporator 7. The temperature of the high-pressure refrigerant leaving the heat flow side of the regenerator 14 further decreases, and its subcooling degree increases. The liquid-phase refrigerant with sufficient subcooling enters the expansion valve 10 for throttling, cooling, and pressure reduction. At the outlet of the expansion valve 10, the refrigerant becomes a gas-liquid two-phase state at low temperature and low pressure with a certain dryness. Subsequently, this refrigerant enters the cold flow side of the evaporator 7 to absorb heat and evaporate, and the temperature of the refrigerant increases and the dryness increases. At the outlet of the evaporator 7, the refrigerant is in a saturated state or a gas-liquid two-phase state with a large dryness. This refrigerant then enters the cold flow side of the regenerator 14 to absorb the heat of the high-pressure refrigerant leaving the second condenser 4, causing the temperature to rise and becoming a superheated gas with a certain degree of superheat. Finally, this refrigerant enters the suction inlet of the compressor 1 and is compressed and pressurized in the compressor 1 to complete a full heat pump cycle.

[0070] When the exhaust temperature of the compressor 1 is relatively high and exceeds the set monitoring value, or the inlet temperature of the water to be heated is relatively low and lower than the set monitoring value, the control system operates the cycle system in the secondary heating mode. The refrigerant leaving the compressor 1 is first cooled in the first condenser 3 and then further cooled in the second condenser 4. At the same time, the water to be heated first enters the cold flow side of the second condenser 4 to absorb the heat of the refrigerant, and the water temperature rises. After leaving the second condenser 4, it then enters the cold flow side of the first condenser 3 to absorb the heat of the refrigerant. Thus, the water to be heated fully absorbs the heat of the refrigerant and rises to a higher water temperature, and the refrigerant is fully cooled and has sufficient subcooling at the outlet of the heat flow side of the second condenser 4. In the first condenser 3 and the second condenser 4, the heat transfer temperature difference between the hot and cold ends of the refrigerant and the water to be heated decreases, achieving better temperature matching, improving the heat transfer efficiency of the condenser, and enhancing the performance of the heat pump cycle system.

[0071] It should be noted that in this embodiment, the heat pump cycle system further includes a control mechanism, and the control mechanism can be a centralized or distributed controller. For example, the controller can be a single microcontroller or composed of multiple distributed microcontrollers. A control program can run in the microcontroller to control the first switching valve 11, the second switching valve 12, the third switching valve 13, the fourth switching valve, the four-way reversing valve 15, and the expansion valve 10 to achieve their functions.

[0072] Compared with the traditional heat pump cycle system, the heat pump cycle system provided by the embodiment of the present invention has the following beneficial effects:

[0073] 1. The heat pump cycle system has two heating modes. When the exhaust temperature of the compressor 1 is relatively high due to changes in the operating environment conditions or the inlet temperature of the water to be heated is relatively low, the heat pump cycle system enters the secondary heating mode. While enabling the water to be heated to have a higher outlet temperature, it fully condenses the high-temperature refrigerant, ensures the superheat degree, and at the same time obtains a better heat exchange temperature difference between the cold end and the hot end in the condenser, with better temperature matching and improved heat exchange efficiency.

[0074] 2. An additional regenerator 14 is added to the heat pump cycle system. After the refrigerant leaves the evaporator 7, it is further heated by the regenerator 14. In addition to ensuring the superheat degree at the suction inlet of the compressor 1, it further cools the temperature of the refrigerant at the outlet of the condenser, increasing the subcooling degree of the refrigerant before the expansion valve.

[0075] 3. After adding an additional sub-condenser and regenerator 14, the defrosting mode of the heat pump cycle system can still be normally realized.

[0076] Based on the above heat pump cycle system, the present invention provides a heat pump cycle control method. As Figure 8 shown, the heat pump cycle control method includes the following steps:

[0077] Obtain the exhaust temperature of the compressor 1;

[0078] Judge whether the exhaust temperature of the compressor 1 is higher than the first temperature value;

[0079] If so, control the first switching valve 11 and the third switching valve 13 to open and the second switching valve 12 to close, so that the refrigerant flowing out of the compressor 1 flows through the first condenser 3 and the second condenser 4 in sequence, and control the water to be heated to flow through the second condenser 4 and the first condenser 3 in sequence to exchange heat with the refrigerant, so that the heat pump cycle system is in the secondary heating mode;

[0080] If not, control the first switching valve 11 and the third switching valve 13 to close and the second switching valve 12 to open, so that the refrigerant flowing out of the compressor 1 directly flows through the second condenser 4, and control the water to be heated to flow through the second condenser 4 to exchange heat with the refrigerant, so that the heat pump cycle system is in the primary heating mode.

[0081] Further, in some embodiments, the heat pump cycle control method further includes the following steps:

[0082] Judge whether the coil of the evaporator 7 needs defrosting;

[0083] If so, control the first switching valve 11 to close, the third switching valve 13 to close, and the second switching valve 12 to open, and control the first port and the third port of the four-way reversing valve 15 to conduct, and the second port and the fourth port to conduct, so that the refrigerant flowing out of the compressor 1 sequentially flows through the first flow path connecting the first port and the third port in the four-way reversing valve 15, the cold-side passage of the regenerator 14, the evaporator 7, the hot-side passage of the regenerator 14, and the second flow path connecting the second port and the fourth port in the four-way reversing valve 15 and then returns to the compressor 1.

[0084] Based on the above heat pump cycle system, the present invention also provides a heat pump cycle control method, as Figure 9 shown, the heat pump cycle control method includes the following steps:

[0085] Obtain the water inlet temperature at the water inlet pipeline 6;

[0086] Judge whether the water inlet temperature is lower than the second temperature value;

[0087] If so, control the first switching valve 11 and the third switching valve 13 to open and the second switching valve 12 to close, so that the refrigerant flowing out of the compressor 1 sequentially flows through the first condenser 3 and the second condenser 4, and control the water to be heated to sequentially flow through the second condenser 4 and the first condenser 3 to exchange heat with the refrigerant, so that the heat pump cycle system is in the secondary heating mode;

[0088] If not, control the first switching valve 11 and the third switching valve 13 to close and the second switching valve 12 to open, so that the refrigerant flowing out of the compressor 1 directly flows through the second condenser 4, and control the water to be heated to flow through the second condenser 4 to exchange heat with the refrigerant, so that the heat pump cycle system is in the primary heating mode.

[0089] Further, in some embodiments, the heat pump cycle control method further includes the following steps:

[0090] Judge whether the coil of the evaporator 7 needs defrosting;

[0091] If so, control the first switching valve 11 to close, the third switching valve 13 to close, and the second switching valve 12 to open, and control the first valve port and the third valve port of the four-way reversing valve 15 to conduct, and the second valve port and the fourth valve port to conduct, so that the refrigerant flowing out of the compressor 1 sequentially flows through the first flow path connecting the first valve port and the third valve port in the four-way reversing valve 15, the cold-side passage of the regenerator 14, the evaporator 7, the hot-side passage of the regenerator 14, and the second flow path connecting the second valve port and the fourth valve port in the four-way reversing valve 15 and then returns to the compressor 1.

[0092] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can be made on the basis of the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A heat pump cycle system, characterized in that, Comprising: A compressor (1) and a first pipeline (2), the first pipeline (2) includes a main pipeline (201), a first branch pipeline (202) and a second branch pipeline (203) that are interconnected, and the outlet of the compressor (1) is communicated with the main pipeline (201); A first condenser (3) and a second condenser (4), the outlet of the first condenser (3) and the inlet of the second condenser (4) are communicated through a second pipeline (5), the outlet of the first branch pipeline (202) is communicated with the inlet of the first condenser (3), and the outlet of the second branch pipeline (203) is communicated with the inlet of the second condenser (4); A water inlet pipeline (6), the water inlet pipeline (6) enables the water to be heated to flow through the second condenser (4) and the first condenser (3) in sequence for heat exchange; An evaporator (7) and an expansion valve (10), the outlet of the second condenser (4), the expansion valve (10), the evaporator (7) and the inlet of the compressor (1) are communicated through pipelines in sequence, and form a circular path for refrigerant circulation with the first pipeline (2) and the second pipeline (5); A first switching valve (11), a second switching valve (12) and a third switching valve (13), the first switching valve (11) is arranged on the first branch pipeline (202), the second switching valve (12) is arranged on the second branch pipeline (203), and the third switching valve (13) is arranged on the second pipeline (5); Wherein, the heat pump cycle system has a primary heating mode in which the first switching valve (11) blocks the first branch pipeline (202), the second switching valve (12) opens the second branch pipeline (203), and the third switching valve (13) blocks the second pipeline (5), and a secondary heating mode in which the first switching valve (11) opens the first branch pipeline (202), the second switching valve (12) blocks the second branch pipeline (203), and the third switching valve (13) opens the second pipeline (5).

2. The heat pump cycle system according to claim 1, wherein The outlet of the second branch pipeline (203) is communicated with the second pipeline (5) and the communication point is A, the second pipeline (5) includes a first section on one side of the communication point A and close to the first condenser (3) and a second section on the other side of the communication point A and close to the second condenser (4), and the third switching valve (13) is arranged on the first section.

3. The heat pump cycle system according to claim 1, wherein The heat exchange area of the first condenser (3) is less than or equal to the heat exchange area of the second condenser (4).

4. The heat pump cycle system according to claim 1, wherein The inlet pipeline (6) includes an inlet pipe section, an intermediate pipe section, and an outlet pipe section. The inlet pipe section is communicated with the water inlet of the second condenser (4). The intermediate pipe section is communicated between the water outlet of the second condenser (4) and the water inlet of the first condenser (3). The outlet pipe section is communicated with the water outlet of the first condenser (3). A first water inlet (601) is formed on the inlet pipe section.

5. The heat pump cycle system according to claim 4, wherein a second water inlet (602) is provided on the intermediate pipe section, and through the second water inlet (602), separate water inlet into the first condenser (3) can be realized in the secondary heating mode.

6. The heat pump cycle system according to claim 5, wherein the intermediate pipe section includes a first pipe section located on one side of the second water inlet (602) and close to the first condenser (3), and a second pipe section located on the other side of the second water inlet (602) and close to the second condenser (4). A fourth switching valve or a check valve is provided on the second pipe section.

7. The heat pump cycle system according to any one of claims 1-6, wherein the outlet of the second condenser (4) is communicated with the inlet of the evaporator (7) through a third pipeline (8). The outlet of the evaporator (7) is communicated with the inlet of the compressor (1) through a fourth pipeline (9). An expansion valve (10) is provided on the third pipeline (8); the heat pump cycle system further includes a regenerator (14). The regenerator (14) has a heat flow side passage and a cold flow side passage. The heat flow side passage is connected in series to the third pipeline (8), and the cold flow side passage is connected in series to the fourth pipeline (9). And the expansion valve (10) is provided between the heat flow side outlet of the regenerator (14) and the evaporator (7).

8. The heat pump cycle system according to claim 7, wherein the heat pump cycle system further includes a four-way reversing valve (15). The first valve port of the four-way reversing valve (15) is communicated with the second branch pipeline (203). The second valve port of the four-way reversing valve (15) is communicated with the inlet of the second condenser (4). The third valve port of the four-way reversing valve (15) is communicated with the cold flow side outlet of the regenerator (14). The fourth valve port of the four-way reversing valve (15) is communicated with the inlet of the compressor (1); wherein, the heat pump cycle system has a defrosting mode in which the first switching valve (11) blocks the first branch pipeline (202), the second switching valve (12) opens the second branch pipeline (203), the third switching valve (13) blocks the second pipeline (5), and the four-way reversing valve (15) is in a state where the first valve port is communicated with the third valve port, and the second valve port is communicated with the fourth valve port.

9. A heat pump cycle control method, characterized in that, For the heat pump cycle system according to any one of claims 1-8, the heat pump cycle control method includes the following steps: Obtain the exhaust temperature of the compressor (1); Judge whether the exhaust temperature of the compressor (1) is higher than a first temperature value; If so, control the first switching valve (11) and the third switching valve (13) to open and the second switching valve (12) to close, so that the refrigerant flowing out of the compressor (1) flows through the first condenser (3) and the second condenser (4) in sequence, and control the water to be heated to flow through the second condenser (4) and the first condenser (3) in sequence to exchange heat with the refrigerant, so that the heat pump cycle system is in the secondary heating mode; If not, control the first switching valve (11) and the third switching valve (13) to close and the second switching valve (12) to open, so that the refrigerant flowing out of the compressor (1) directly flows through the second condenser (4), and control the water to be heated to flow through the second condenser (4) to exchange heat with the refrigerant, so that the heat pump cycle system is in the primary heating mode.

10. The heat pump cycle control method according to claim 9, characterized in that, The heat pump cycle control method further includes the following steps: Judge whether the coil of the evaporator (7) needs defrosting; If so, control the first switching valve (11) to close, the third switching valve (13) to close, and the second switching valve (12) to open, and control the first port and the third port of the four-way reversing valve (15) to conduct, and the second port and the fourth port to conduct, so that the refrigerant flowing out of the compressor (1) flows through the first flow path connecting the first port and the third port of the four-way reversing valve (15), the cold-side passage of the regenerator (14), the evaporator (7), the hot-side passage of the regenerator (14), and the second flow path connecting the second port and the fourth port of the four-way reversing valve (15) in sequence and then returns to the compressor (1).

11. A heat pump cycle control method, characterized in that, For the heat pump cycle system according to any one of claims 1-8, the heat pump cycle control method includes the following steps: Obtain the water inlet temperature at the water inlet pipe (6); Judge whether the water inlet temperature is lower than the second temperature value; If so, control the first switching valve (11) and the third switching valve (13) to open and the second switching valve (12) to close, so that the refrigerant flowing out of the compressor (1) flows through the first condenser (3) and the second condenser (4) in sequence, and control the water to be heated to flow through the second condenser (4) and the first condenser (3) in sequence to exchange heat with the refrigerant, so that the heat pump cycle system is in the secondary heating mode; If not, control the first switching valve (11) and the third switching valve (13) to close and the second switching valve (12) to open, so that the refrigerant flowing out of the compressor (1) directly flows through the second condenser (4), and control the water to be heated to flow through the second condenser (4) to exchange heat with the refrigerant, so that the heat pump cycle system is in the primary heating mode.

12. The heat pump cycle control method according to claim 11, characterized in that, The heat pump cycle control method further includes the following steps: Judge whether the coil of the evaporator (7) needs defrosting; If so, control the first switching valve (11) to close, the third switching valve (13) to close, and the second switching valve (12) to open, and control the first valve port and the third valve port of the four-way reversing valve (15) to conduct, and the second valve port and the fourth valve port to conduct, so that the refrigerant flowing out of the compressor (1) sequentially flows through the first flow path connecting the first valve port and the third valve port of the four-way reversing valve (15), the cold-side passage of the regenerator (14), the evaporator (7), the hot-side passage of the regenerator (14), and the second flow path connecting the second valve port and the fourth valve port of the four-way reversing valve (15), and then returns to the compressor (1).

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