Dual-cold-source integrated air source heat pump rooftop unit and control method thereof
By designing a dual-source integrated air-source heat pump rooftop unit, the refrigerant circulation path is optimized, solving the problems of low energy efficiency and defrosting reliability in conventional air conditioning systems, achieving efficient cooling and heating, and reducing system energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG KING CO LTD
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-29
AI Technical Summary
Conventional rooftop air conditioning systems suffer from problems such as high system power consumption, high engineering costs, poor cooling capacity, low energy efficiency ratio, and the impact of defrosting on compressor reliability.
The rooftop unit adopts a dual-source integrated air-source heat pump, which integrates water-cooled cooling, air-source heat pump heating, and component-independent defrosting functions. By having the refrigerant work in different heat exchangers in different modes, combined with a water-cooled condenser, finned coil unit, and cooling tower, the refrigerant circulation path is optimized to avoid the refrigerant passing through the four-way valve.
It improves cooling efficiency, lowers condensing temperature, reduces system energy consumption, achieves efficient cooling and heating, and does not interrupt heating during defrosting, thus improving the overall energy efficiency ratio of the system.
Smart Images
Figure CN122107485A_ABST
Abstract
Description
Technical Field
[0001] This disclosure pertains to the field of heat pump system technology, and in particular to a dual-cold-source integrated air-source heat pump roof unit and its control method. Background Technology
[0002] Conventional rooftop air conditioning systems generally employ one of the following two methods: 1. Water-cooled direct expansion system, 2. Air-cooled direct expansion heat pump system.
[0003] In a water-cooled direct expansion system, a water-cooled compressor-condenser unit supplies 6°C refrigerant to the air-side heat exchanger to cool the room air. The water-cooled condenser transfers the condensation heat to the cooling water, which then discharges the condensation heat to the outdoor atmosphere via a cooling tower. Typically, there is a long cooling water circulation pipeline between the water-cooled compressor-condenser unit and the cooling tower, requiring a high-power, high-lift water pump to drive the cooling water circulation. This results in high system power consumption and significant construction and space requirements, leading to higher project costs. Furthermore, to meet heating needs during winter and transitional seasons, the system also requires additional heating equipment such as boilers or electric heaters.
[0004] In air-cooled direct expansion heat pump systems, the air-cooled compressor-condenser unit ultimately discharges heat to the outdoor atmosphere through the air-cooled condenser. However, the outdoor air temperature is already high during cooling, resulting in poor cooling capacity. Especially since air-cooled chiller-water units exchange sensible heat with the outdoor air via finned heat exchangers, the air-side heat transfer coefficient is low, leading to a very high condensing temperature and an energy efficiency ratio typically between 2.6 and 3.0. Furthermore, conventional air-cooled heat pumps require components such as gas-liquid separators and four-way valves to facilitate switching between heating and cooling, avoid wet shock to the compressor during winter defrosting, and improve unit reliability. However, in actual operation, the low-pressure refrigerant exiting the evaporator must pass through the four-way valve and gas-liquid separator, creating additional resistance and reducing the unit's operating efficiency. Summary of the Invention
[0005] To address the technical problems existing in the prior art, this disclosure integrates water-cooled refrigeration, air-source heat pump heating, and independent defrosting functions, resulting in high refrigeration efficiency, uninterrupted heating during defrosting, high integration, low operating costs, and strong reliability.
[0006] On one hand, this disclosure proposes a dual-source integrated air-source heat pump rooftop unit, including a refrigerant circulation loop. The refrigerant circulation loop includes a compressor, a water-cooled condenser, an air handling unit, and at least two sets of parallel-connected finned coil units. The compressor outlet is connected to the oil separator inlet. The oil separator gas outlet is connected to a second electric valve and a third electric valve. The third electric valve is sequentially connected to the water-cooled condenser, a fourth electric valve, a liquid receiver, and a dryer filter. The dryer filter outlet is divided into two paths: one path is connected to a first throttle valve, which is connected to the liquid-side interface of the air handling unit. The air-side interface of the air handling unit is connected to the second electric valve and the first electric valve. The first electric valve is sequentially connected to the gas-liquid separator and the compressor inlet. The liquid-side interface of the air handling unit is also connected to the first one-way valve. The outlet of the first one-way valve is connected to the inlet of the liquid receiver. Another path of the outlet of the dryer filter is connected to the first solenoid valve. The first solenoid valve is connected to each finned coil unit. The finned coil unit is connected to the inlet of the gas-liquid separator. In the cooling mode, the gaseous refrigerant discharged from the compressor is condensed by the water-cooled condenser, throttled by the first throttle valve, and then evaporated by the air handling unit. The evaporated refrigerant returns to the compressor after passing through the first electric valve and the gas-liquid separator. In the heating mode, the gaseous refrigerant discharged from the compressor enters the air handling unit for condensation. The condensed refrigerant then enters the finned coil unit for evaporation. The evaporated refrigerant returns to the compressor after passing through the gas-liquid separator.
[0007] Preferably, the oil outlet of the oil separator is directly connected to the suction side of the compressor via a second solenoid valve.
[0008] Preferably, the outlet of the water-cooled condenser is connected to the inlet of the two-way water valve, the outlet of the two-way water valve is connected to the inlet of the cooling tower, the outlet of the cooling tower is connected to the inlet of the cooling water circulation pump, the outlet of the cooling water circulation pump is connected to the inlet of the one-way water valve, and the outlet of the one-way water valve is connected to the inlet of the water-cooled condenser.
[0009] Preferably, the air handling unit is enclosed by a panel forming a closed cavity, and a filter, a heat exchanger, and an EC fan are arranged sequentially along the air handling direction inside the cavity. The heat exchanger is connected to the gas-side and liquid-side interfaces of the refrigeration cycle loop, respectively.
[0010] Preferably, the unit includes two sets of finned coil units. The outlet of the first solenoid valve is divided into two paths, which are respectively connected to the inlets of the second throttle valve and the third throttle valve. The outlet of the second throttle valve is connected to the liquid side interface of the first finned coil, and the outlet of the third throttle valve is connected to the liquid side interface of the second finned coil. The gas side interface of the first finned coil is connected to interface c of the first four-way valve, and the gas side interface of the second finned coil is connected to interface c of the second four-way valve. The interfaces b of the first four-way valve and the second four-way valve are both connected to the inlet of the gas-liquid separator.
[0011] Preferably, the inlet of the second check valve is connected to the outlet of the second throttle valve, the inlet of the third check valve is connected to the outlet of the third throttle valve, and the outlets of the second and third check valves are connected in parallel to the inlet of the reservoir; the high-pressure port a of the first four-way valve and the high-pressure port a of the second four-way valve are both connected to the gas outlet of the oil separator.
[0012] On the other hand, this disclosure also proposes a control method for a heat pump unit, applied to the dual-source integrated air-source heat pump rooftop unit as described above. The control method includes: the unit receiving a mode command; if the mode command is a cooling command, controlling multiple valves to switch to the cooling circuit so that the refrigerant circulates according to the cooling mode path; if the mode command is a heating command, controlling multiple valves to switch to the heating circuit so that the refrigerant circulates according to the heating mode path.
[0013] Preferably, the refrigeration mode path cycle is as follows: the high-temperature, high-pressure gaseous refrigerant discharged from the compressor passes through an oil separator and a third electric valve. The gaseous refrigerant then enters a water-cooled condenser, where it releases heat to the circulating cooling water and condenses into a high-pressure liquid refrigerant. The circulating cooling water is driven by a cooling water circulation pump into a cooling tower, where it exchanges heat with the air to cool down. After cooling down, it returns to the water-cooled condenser to continue absorbing the condensation heat of the high-temperature refrigerant. The refrigerant flows through a fourth electric valve, a liquid receiver, and a dryer filter before entering a first throttling valve. After being throttled by the first throttling valve, it becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant. It then exchanges heat with the indoor air through an air handling unit, absorbing heat from the indoor air to cool it down and evaporate into a low-pressure gaseous refrigerant. After that, it returns to the gas-liquid separator through the first electric valve. After gas-liquid separation, it returns directly to the compressor, unlike conventional air-cooled heat pumps which require passing through a four-way valve before entering the compressor. The heating mode path loop is as follows: the high-temperature and high-pressure gaseous refrigerant discharged from the compressor enters the air handling unit through the oil separator and the second electric valve. The refrigerant releases heat to the indoor air to heat it and then condenses into a high-pressure liquid refrigerant. The refrigerant flows through the first one-way valve, the liquid receiver, the dryer filter, and the first solenoid valve. Then, it is throttled by the second throttle valve and the third throttle valve to become a low-temperature and low-pressure gas-liquid two-phase refrigerant. It then passes through the first finned coil and the second finned coil respectively and exchanges heat with the outdoor air. After evaporating into a low-pressure gaseous refrigerant, it finally returns to the compressor through the low-pressure interface c and interface b of the first four-way valve and the second four-way valve.
[0014] Preferably, during heating mode operation, if frost is detected on at least one finned coil unit, the four-way valve connected to it is switched to allow the refrigerant to circulate along the defrost path. Specifically, the defrost path circulation involves allowing a portion of the high-temperature refrigerant discharged from the compressor to flow into that finned coil for defrosting, while simultaneously maintaining the remaining finned coils to continue absorbing heat from the outdoor air.
[0015] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain the preferred examples of this disclosure.
[0016] The above-mentioned technical solution has the following advantages or beneficial effects: The heat pump unit of this disclosure, by setting up three heat exchangers, allows the refrigerant to operate in two of them in different modes. This enables the unit to use a more energy-efficient water-cooled condensation method for cooling in summer, where the refrigerant exchanges heat with the circulating cooling water, significantly reducing the condensation temperature and improving the system's cooling efficiency. In the unit's refrigeration system design, the refrigerant vapor from the evaporator does not pass through a four-way valve, resulting in a smaller pressure drop in the suction pipe and higher cooling efficiency. During transitional seasons or when heating is required in winter, the unit uses an air-source heat pump mode for heating. In summary, the unit of this disclosure, integrating a water-cooled condenser, finned coil heat exchange unit, cooling tower and hydraulic module, and air handling unit, uses the most energy-efficient system design in all operating modes, resulting in a high overall system energy efficiency ratio and greater energy saving and environmental protection compared to existing products. Of course, no single technical solution of this disclosure may simultaneously achieve all the advantages described above. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on the provided drawings without any creative effort.
[0018] Figure 1 This is a schematic diagram of the structure of a dual-cold-source integrated air-source heat pump roof unit according to an embodiment of the present disclosure; Figure 2 This is a schematic diagram of the refrigerant flow direction of a unit in cooling mode according to an embodiment of the present disclosure; Figure 3 This is a schematic diagram of the refrigerant flow direction of a unit in heating mode according to an embodiment of the present disclosure; Figure 4 This is a schematic diagram of the refrigerant flow of a unit in heating and defrosting modes according to an embodiment of the present disclosure; Figure 5 This is a schematic diagram of the structure of an air handling unit according to an embodiment of the present disclosure.
[0019] The components include: compressor 1, oil separator 2, first four-way valve 3, water-cooled condenser 4, first electric valve 5, liquid receiver 6, dryer filter 7, first solenoid valve 8, first throttle valve 9, air handling unit 10, gas-liquid separator 11, first one-way valve 12, second one-way valve 13, second four-way valve 14, second electric valve 15, third electric valve 16, third one-way valve 17, fourth electric valve 18, first finned coil 19, second finned coil 20, second throttle valve 21, third throttle valve 22, second solenoid valve 23, cooling tower 24, water circuit two-way valve 25, cooling water circulation pump 26, water circuit one-way valve 27, filter 28, heat exchanger 29, EC fan 30, and box plate 31. Detailed Implementation
[0020] The technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of this disclosure and are intended to explain the inventive concept. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.
[0021] The terms “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “axial,” “radial,” “circumferential,” “center,” “longitudinal,” “transverse,” “length direction,” “width direction,” and “thickness direction” used in the description indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are for the purpose of simplifying the description only and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation.
[0022] The terms "first," "second," etc., used in the description are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of that feature. The term "multiple" means two or more, unless otherwise explicitly specified.
[0023] Unless otherwise explicitly specified and limited, the terms "connected," "connected," etc., used in the description should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments according to the specific circumstances.
[0024] Unless otherwise explicitly specified and limited, the terms "above," "below," or "on top of" the second feature can mean that the first and second features are in direct contact or indirect contact through an intermediate medium. Furthermore, "above," "on top of," or "on top of" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," or "below" the second feature can mean that the first and second features are in direct contact or indirect contact through an intermediate medium. Moreover, "below," "below," or "below" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0025] The term "a specific embodiment" as used in the description means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0026] refer to Figure 1 One specific embodiment of this disclosure proposes a dual-source integrated air-source heat pump rooftop unit capable of operating in both cooling and heating modes. The unit includes a cooling circulation loop, a cooling water circulation loop, and an air conditioning system loop.
[0027] The refrigeration cycle includes a compressor 1, an oil separator 2, a water-cooled condenser 4, a first electric valve 5, a liquid receiver 6, a dryer filter 7, a first solenoid valve 8, a first throttle valve 9, an air handling unit 10, a gas-liquid separator 11, a first check valve 12, a second electric valve 15, a third electric valve 16, a fourth electric valve 18, a second solenoid valve 23, and a finned coil unit. The cooling water circulation cycle includes a cooling tower 24, a two-way water valve 25, a cooling water circulation pump 26, and a one-way water valve 27.
[0028] The air conditioning system circuit includes an air handling unit 10, which includes a panel 31, a filter 28, a heat exchanger 29, and an EC fan 30.
[0029] The finned coil unit includes a four-way valve, a finned coil, a throttle valve, and a check valve. Preferably, the finned coil unit is arranged in two parallel sets, including a first four-way valve 3, a second four-way valve 14, a first finned coil 19, a second finned coil 20, a second throttle valve 21, a third throttle valve 22, a second check valve 13, and a third check valve 17.
[0030] The high-pressure outlet of compressor 1 is connected to the inlet of oil separator 2. The oil outlet of oil separator 2 is connected to the suction side of compressor 1 via second solenoid valve 23. The gas outlet of oil separator 2 is multi-connected, connected to the inlet of second electric valve 15 and the inlet of third electric valve 16 respectively. The outlet of third electric valve 16 is connected to the gas side interface of water-cooled condenser 4. The liquid side interface of water-cooled condenser 4 is connected to the inlet of fourth electric valve 18. The outlet of fourth electric valve 18 is connected to the inlet of liquid receiver 6. The outlet of liquid receiver 6 is connected to the inlet of dryer filter 7. The outlet of dryer filter 7 is divided into two paths, one connected to the inlet of first throttle valve 9 and the other connected to the inlet of first solenoid valve 8.
[0031] The outlet of the second electric valve 15 is connected to the air-side interface of the air handling unit 10. The air-side interface of the air handling unit 10 is also connected to the inlet of the first electric valve 5. The outlet of the first electric valve 5 is connected to the inlet of the gas-liquid separator 11. The outlet of the gas-liquid separator 11 is connected to the air inlet of the compressor 1. The liquid-side interface of the air handling unit 10 is connected to the outlet of the first throttle valve 9. The liquid-side outlet of the air handling unit 10 is also connected to the inlet of the first check valve 12.
[0032] Preferably, the outlet of the fourth electric valve 18 is connected in parallel with the outlet of the first check valve 12, and then together they are connected to the inlet of the reservoir 6.
[0033] The outlet of the water-cooled condenser 4 is connected to the inlet of the two-way water valve 25, the outlet of the two-way water valve 25 is connected to the inlet of the cooling tower 24, the outlet of the cooling tower 24 is connected to the inlet of the cooling water circulation pump 26, the outlet of the cooling water circulation pump 26 is connected to the inlet of the one-way water valve 27, and the outlet of the one-way water valve 27 is connected to the inlet of the water-cooled condenser 4, thus forming a cooling water circulation loop.
[0034] Preferably, taking two sets of parallel finned coil units as an example, the outlet of the first solenoid valve 8 is divided into two paths, which are respectively connected to the inlets of the second throttle valve 21 and the third throttle valve 22; the outlet of the second throttle valve 21 is connected to the liquid-side interface of the first finned coil 19, and the outlet of the third throttle valve 22 is connected to the liquid-side interface of the second finned coil 20; the inlet of the second check valve 13 is connected to the outlet of the second throttle valve 21, and the inlet of the third check valve 17 is connected to the outlet of the third throttle valve 22. The outlets of the second one-way valve 13 and the third one-way valve 17 are connected in parallel to the inlet of the liquid reservoir 6; the gas-side interface of the first finned coil 19 is connected to interface c of the first four-way valve 3, and the gas-side interface of the second finned coil 20 is connected to interface c of the second four-way valve 14; the low-pressure interfaces b of the first four-way valve 3 and the second four-way valve 14 are both connected to the inlet of the gas-liquid separator 11, and the high-pressure interfaces a of the first four-way valve 3 and the second four-way valve 14 are both connected to the gas outlet of the oil separator 2. The aforementioned finned coil units are not limited to two sets; in actual applications, multiple sets of finned coil units can be connected in parallel depending on the usage environment.
[0035] refer to Figure 5 One specific embodiment of this disclosure proposes an air handling unit. The air handling unit 10 has a box plate 31 forming a closed cavity. A filter 28, a heat exchanger 29, and an EC fan 30 are arranged sequentially along the air handling direction inside the cavity. The heat exchanger 29 is connected to the gas side and liquid side interfaces of the refrigeration cycle loop, respectively.
[0036] refer to Figure 2 In one specific embodiment of this disclosure, the unit operates in cooling mode, with the first electric valve 5, the third electric valve 16, and the fourth electric valve 18 open, the second electric valve 15 closed, and the first solenoid valve 8 closed. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 1 passes through the oil separator 2 and the third electric valve 16. The gaseous refrigerant then enters the water-cooled condenser 4, where it releases heat to the circulating cooling water and condenses into a high-pressure liquid refrigerant. The circulating cooling water is driven by the cooling water circulation pump 26 into the cooling tower 24, where it exchanges heat with the air to cool down, and then returns to the water-cooled condenser 4 to continue absorbing the condensation heat of the high-temperature refrigerant. The refrigerant flows through the fourth electric valve 18, the liquid receiver 6, and the dryer filter 7 before entering the first throttle valve 9. After being throttled by the first throttle valve 9, it becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant. Then, it passes through the air handling unit 10 to exchange heat with the indoor air, absorbing heat from the indoor air to cool it down and evaporate it into a low-pressure gaseous refrigerant. After that, it returns to the gas-liquid separator 11 through the first electric valve 5. After gas-liquid separation, it returns directly to the compressor 1, unlike conventional air-cooled heat pumps which require passing through a four-way valve before entering the compressor 1.
[0037] refer to Figure 3In a specific embodiment of this disclosure, the unit operates in heating mode, with the first electric valve 5, the third electric valve 16, and the fourth electric valve 18 closed, the four-way valve de-energized and its c-port and b-port connected, and the second electric valve 15 and the first solenoid valve 8 open. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 1 enters the air handling unit 10 via the oil separator 2 and the second electric valve 15. The refrigerant releases heat to the indoor air, heating it and condensing it into a high-pressure liquid refrigerant. The refrigerant flows through the first one-way valve 12, the liquid receiver 6, the dryer filter 7, and the first solenoid valve 8, and then is throttled by the second throttling valve 21 and the third throttling valve 22 into a low-temperature, low-pressure gas-liquid two-phase refrigerant. It then passes through the first finned coil 19 and the second finned coil 20 respectively, exchanging heat with the outdoor air, and then evaporates into a low-pressure gaseous refrigerant. It is then introduced into the gas-liquid separator 11 via the low-pressure ports c and b of the first four-way valve 3 and the second four-way valve 14, and finally enters the air inlet of the compressor 1.
[0038] refer to Figure 4 One specific embodiment of this disclosure proposes that when the unit is operating in heating mode, if a certain finned coil is severely frosted, independent defrosting is performed simultaneously. Taking the first finned coil 19 as an example, the corresponding first four-way valve 3 is energized and switched, and interface a and interface c of the first four-way valve 3 are connected. Most of the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 enters the air handling unit 10, where it heats the indoor air as described above. The remaining high-temperature and high-pressure gaseous refrigerant enters the first finned coil 19 after passing through interface a and interface c of the first four-way valve 3, heating the frost layer on the fin surface, melting the frost, and then condensing it into a high-pressure liquid. The condensed liquid refrigerant enters the liquid receiver 6 through the second one-way valve 13 for recirculation. Thus, while each finned coil is independently defrosted, the unit can still output normal heat to heat the indoor air.
[0039] In summary, this disclosure utilizes a three-heat-exchange configuration, with the refrigerant operating in two of the heat exchangers under different modes. This allows the unit to employ water-cooled condensation in summer, where the refrigerant directly exchanges heat with the circulating cooling water through the condenser heat exchange tubes, significantly reducing the condensation temperature and improving system cooling efficiency. In the unit's refrigeration system design, the opening and closing of four electric valves in the pipeline allows the refrigerant in the refrigerant circulation loop to flow through each heat exchanger and component in different states. These state changes within the heat exchangers achieve cooling and heating of the air in the air handling unit under various modes. The refrigerant vapor from the evaporator does not need to pass through a four-way valve, resulting in a smaller suction pipe pressure drop and higher cooling efficiency. During transitional seasons or winter heating, the unit uses an air-source heat pump mode for heating. Overall, this disclosed unit employs the most energy-efficient system design in all operating modes, resulting in a high overall system energy efficiency ratio and greater energy saving and environmental friendliness compared to existing products.
[0040] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Various changes and modifications may be made to the present disclosure without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of the claimed disclosure.
Claims
1. A dual-source integrated air-source heat pump rooftop unit, comprising a refrigerant circulation loop, wherein the refrigerant circulation loop includes a compressor (1), a water-cooled condenser (4), an air handling unit (10), and at least two sets of parallel-connected finned coil units; characterized in that: The compressor outlet is connected to the oil separator (2) inlet. The oil separator gas outlet is connected to the second electric valve (15) and the third electric valve (16) respectively. The third electric valve is connected in sequence to the water-cooled condenser, the fourth electric valve (18), the liquid receiver (6), and the dryer filter (7). The dryer filter outlet is divided into two paths. One path is connected to the first throttle valve (9). The first throttle valve is connected to the liquid side interface of the air handling unit. The air side interface of the air handling unit is connected to the second electric valve and the first electric valve (5) respectively. The first electric valve is connected in sequence to the gas-liquid separator (11) and the compressor inlet. The liquid side interface of the air handling unit is also connected to the first check valve (12). The outlet of the first check valve is connected to the liquid receiver inlet. The other path of the dryer filter outlet is connected to the first solenoid valve (8). The first solenoid valve is connected to each finned coil unit respectively. The finned coil unit is connected to the gas-liquid separator inlet. In cooling mode, the gaseous refrigerant discharged by the compressor is condensed by a water-cooled condenser, throttled by the first throttle valve, and then evaporated by the air handling unit. The evaporated refrigerant then returns to the compressor after passing through the first electric valve and the gas-liquid separator in sequence. In heating mode: the gaseous refrigerant discharged from the compressor enters the air handling unit for condensation, the condensed refrigerant then enters the finned coil unit for evaporation, and the evaporated refrigerant returns to the compressor via the gas-liquid separator.
2. The dual-cold-source integrated air-source heat pump rooftop unit according to claim 1, characterized in that: The oil outlet of the oil separator is directly connected to the suction side of the compressor via the second solenoid valve (23).
3. The dual-cold-source integrated air-source heat pump rooftop unit according to claim 1, characterized in that: The outlet of the water-cooled condenser is connected to the inlet of the two-way water valve (25), the outlet of the two-way water valve is connected to the inlet of the cooling tower (24), the outlet of the cooling tower is connected to the inlet of the cooling water circulation pump (26), the outlet of the cooling water circulation pump is connected to the inlet of the one-way water valve (27), and the outlet of the one-way water valve is connected to the inlet of the water-cooled condenser.
4. The dual-cold-source integrated air-source heat pump rooftop unit according to claim 1, characterized in that: The air handling unit's box panel (31) forms a closed cavity. Inside the cavity, a filter (28), a heat exchanger (29), and an EC fan (30) are arranged sequentially along the air handling direction. The heat exchanger is connected to the gas-side and liquid-side interfaces of the refrigeration cycle loop, respectively.
5. The dual-cold-source integrated air-source heat pump rooftop unit according to claim 1, characterized in that: The unit includes two sets of finned coil units. The outlet of the first solenoid valve is divided into two paths, which are connected to the inlets of the second throttle valve (21) and the third throttle valve (22), respectively. The outlet of the second throttle valve is connected to the liquid side interface of the first finned coil (19), and the outlet of the third throttle valve is connected to the liquid side interface of the second finned coil (20). The gas side interface of the first finned coil is connected to the interface c of the first four-way valve (3), and the gas side interface of the second finned coil is connected to the interface c of the second four-way valve (14). The interfaces b of the first four-way valve and the second four-way valve are both connected to the inlet of the gas-liquid separator.
6. The dual-cold-source integrated air-source heat pump rooftop unit according to claim 5, characterized in that: The inlet of the second check valve (13) is connected to the outlet of the second throttle valve, the inlet of the third check valve (17) is connected to the outlet of the third throttle valve, and the outlets of the second check valve and the third check valve are connected in parallel to the inlet of the reservoir; the high pressure port a of the first four-way valve and the high pressure port a of the second four-way valve are both connected to the gas outlet of the oil separator.
7. A control method for a heat pump unit, applied to a dual-cold-source integrated air-source heat pump rooftop unit as described in any one of claims 1-6, characterized in that: The control method includes: the unit receiving a mode command; if the mode command is a cooling command, controlling multiple valves to switch to the cooling circuit so that the refrigerant circulates according to the cooling mode path; if the mode command is a heating command, controlling multiple valves to switch to the heating circuit so that the refrigerant circulates according to the heating mode path.
8. The control method for a heat pump unit according to claim 7, characterized in that: The specific cooling mode circulation path is as follows: The high-temperature, high-pressure gaseous refrigerant discharged from the compressor passes through the oil separator and the third electric valve. The gaseous refrigerant then enters the water-cooled condenser, where it releases heat to the circulating cooling water and condenses into a high-pressure liquid refrigerant. The circulating cooling water is driven by the cooling water circulation pump into the cooling tower, where it exchanges heat with the air to cool down. After cooling down, it returns to the water-cooled condenser to continue absorbing the condensation heat of the high-temperature refrigerant. The refrigerant flows through the fourth electric valve, the liquid receiver, and the dryer filter before entering the first throttling valve. After being throttled by the first throttling valve, it becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant. It then exchanges heat with the indoor air through the air handling unit, absorbing heat from the indoor air to cool it down and evaporate into a low-pressure gaseous refrigerant. After that, it returns to the gas-liquid separator through the first electric valve. After gas-liquid separation, it returns directly to the compressor, unlike conventional air-cooled heat pumps which require passing through a four-way valve before entering the compressor. The heating mode path loop is as follows: the high-temperature and high-pressure gaseous refrigerant discharged from the compressor enters the air handling unit through the oil separator and the second electric valve. The refrigerant releases heat to the indoor air to heat it and then condenses into a high-pressure liquid refrigerant. The refrigerant flows through the first one-way valve, the liquid receiver, the dryer filter, and the first solenoid valve. Then, it is throttled by the second throttle valve and the third throttle valve to become a low-temperature and low-pressure gas-liquid two-phase refrigerant. It then passes through the first finned coil and the second finned coil respectively and exchanges heat with the outdoor air. After evaporating into a low-pressure gaseous refrigerant, it finally returns to the compressor through the low-pressure interface c and interface b of the first four-way valve and the second four-way valve.
9. A control method for a heat pump unit, applied to the dual-cold-source integrated air-source heat pump rooftop unit as described in claim 6, characterized in that: The control method includes: receiving a mode command; if the mode command is a cooling command, controlling multiple valves to switch to the cooling circuit, so that the refrigerant circulates according to the cooling mode path; if the mode command is a heating command, controlling multiple valves to switch to the heating circuit, so that the refrigerant circulates according to the heating mode path; during the operation of the heating mode, if at least one finned coil unit is detected to be frosted, controlling the four-way valve connected to it to switch, so that the refrigerant circulates according to the defrosting path.
10. The control method for a heat pump unit according to claim 9, characterized in that: The defrosting path cycle specifically involves allowing a portion of the high-temperature refrigerant discharged from the compressor to flow into the finned coil for defrosting, while simultaneously maintaining the remaining finned coils to continue absorbing heat from the outdoor air.