Heat pump device and control method thereof

Abstract

The application relates to a heat pump device and a control method thereof. The heat pump device and the control method thereof comprise a first circuit, a second circuit, a third circuit, an energy storage tank and a control unit. The first circuit is used for heat pump refrigerant circulation; the energy storage tank is used for storing heat exchange liquid; the second circuit is used for conveying the heat exchange liquid to the compressor surface for heating and then returning to the energy storage tank; the third circuit is used for conveying the heat exchange liquid to the outdoor side heat exchanger for defrosting and then returning to the energy storage tank; and the control unit is electrically connected with the first circuit, the second circuit and the third circuit respectively and controls the on-off of the circuits. The heat pump device and the control method thereof have the advantages of avoiding energy waste and greatly improving the capacity energy efficiency of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat pump, in particular to a heat pump device and a control method thereof. BACKGROUND

[0002] In the prior art, the heat pump device such as air conditioner and water heater for heating or hot water supply is generally provided with a four-way valve, an outdoor heat exchanger and a compressor located outdoors. The heat generated by the compressor during operation is directly dissipated in the external environment, resulting in waste of energy.

[0003] On the other hand, the existing heat pump device directly enters defrosting by switching direction using the four-way valve, so that the outdoor heat exchanger acts as a condenser for defrosting during defrosting. Although this method can defrost, it loses more heat at low temperature and ultra-low temperature, and the room temperature or water temperature drops significantly and rises slowly. Frequent defrosting leads to a significant reduction in the capacity and energy efficiency of the unit, and the utilization rate of energy is extremely low. SUMMARY

[0004] Therefore, the purpose of the present application is to overcome the defects or deficiencies of the prior art, and to provide a heat pump device.

[0005] The heat pump device comprises a first circuit, a second circuit, a third circuit, an energy storage tank and a control unit. The first circuit is used for heat pump refrigerant circulation and comprises a compressor, an outdoor heat exchanger and a four-way valve. The energy storage tank is used for storing heat exchange liquid. The second circuit is used for delivering the heat exchange liquid to the surface of the compressor for heating and then returning to the energy storage tank. The third circuit is used for delivering the heat exchange liquid to the outdoor heat exchanger for defrosting and then returning to the energy storage tank. The control unit is electrically connected to the first circuit, the second circuit and the third circuit and controls the on-off thereof.

[0006] The heat pump device of the present application can heat by the first circuit, store the heat generated during the heating process of the first circuit by the second circuit, and avoid waste of energy. When the temperature of the energy storage tank is greater than the set temperature, the third circuit is started to deliver the heat of the energy storage tank to the first circuit for heat exchange, thereby prolonging the time of normal heating of the first circuit and greatly improving the capacity and energy efficiency of the system.

[0007] Further, the control unit comprises a temperature sensor and a timer. The temperature sensor detects the temperature of the heat exchange liquid inside the energy storage tank and the ambient temperature, and the timer detects the operation time of the first circuit of the compressor heat recovery system during heating.

[0008] Further, the first circuit further comprises an indoor side heat exchanger, two of the four-way valve interfaces are connected to the indoor side heat exchanger and the side of the outdoor side heat exchanger connected to the side of the outdoor side heat exchanger through pipes, the other two of the four-way valve interfaces are connected to the outlet and the inlet of the compressor through pipes, and the other side of the outdoor side heat exchanger and the indoor side heat exchanger are connected through pipes, thereby forming a circuit for a heat pump refrigerant cycle.

[0009] The present application also provides a heat pump device control method, which is executed in the heat pump device described above, comprising the following steps: operating the first circuit with the outdoor side heat exchanger as an evaporator; operating the second circuit after the first circuit performs heating; comparing the ambient temperature with the set ambient temperature; if the ambient temperature is not less than the set ambient temperature, comparing the heat exchange liquid temperature in the energy storage tank with the set temperature to determine whether to operate the third circuit; if the ambient temperature is less than the set ambient temperature, comparing the heat exchange liquid temperature in the energy storage tank and / or the operating time of the first circuit to determine whether to operate the third circuit or switch the four-way valve direction.

[0010] Further, the step of comparing the heat exchange liquid temperature in the energy storage tank with the set temperature to determine whether to operate the third circuit comprises the following steps: if the heat exchange liquid temperature is not less than the set temperature, operating the third circuit until the heat exchange liquid temperature is less than the set temperature, and then disconnecting the third circuit; if the heat exchange liquid temperature is less than the set temperature, not operating the third circuit.

[0011] Further, the step of comparing the heat exchange liquid temperature in the energy storage tank and / or the operating time of the first circuit to determine whether to operate the third circuit or switch the four-way valve direction comprises the following steps: if the heat exchange liquid temperature is not less than the set temperature and / or the operating time of the first circuit is not greater than the set time, operating the third circuit until the heat exchange liquid temperature is less than the set temperature, and then disconnecting the third circuit; after disconnecting the third circuit, comparing the operating time of the first circuit with the set time, if the operating time of the first circuit is greater than the set time, switching the four-way valve direction, and the outdoor side heat exchanger as a condenser; during the defrosting process, detecting the temperature of the outdoor side heat exchanger, and when the outdoor side heat exchanger reaches the set defrosting temperature, ending the defrosting and switching the four-way valve direction, and the outdoor side heat exchanger as an evaporator.

[0012] Further, the second circuit is operated simultaneously with the third circuit; or the second circuit is disconnected when the third circuit is operated; the second circuit is operated when the third circuit is closed, and the third circuit and the second circuit are independently operated.

[0013] Further, the set environment temperature is a temperature threshold at which the outdoor-side heat exchanger is defrosted when operated.

[0014] Further, the set time is a time at which the first circuit is defrosted after continuous operation.

[0015] Further, the set defrosting temperature is greater than or equal to the set environment temperature.

[0016] In order to better understand and implement, the present application is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The overall flow chart of the heat pump device control method in the present application;

[0018] Figure 2 The flow chart of the sub-step when the environment temperature is not less than the set environment temperature in the heat pump device control method in the present application;

[0019] Figure 3 The flow chart of the sub-step when the environment temperature is less than the set environment temperature in the heat pump device control method in the present application;

[0020] Figure 4 The structural schematic diagram of the heat pump device in the present application. DETAILED DESCRIPTION

[0021] The inventor analyzes the existing heat pump device, and finds that the heat pump device is in working state and generates a large amount of heat in both the heating stage and the cooling stage, which is directly discharged to the outside environment, causing certain energy waste, and the outdoor heat exchanger needs a large amount of heat when defrosting, so the heat generated by the compressor can be stored and utilized in defrosting work, and therefore the present application designs a heat pump device capable of recycling the heat energy of the compressor.

[0022] Please refer to Figure 4The heat pump device of the present application comprises a first circuit, a second circuit, a third circuit, an energy storage tank 7 and a control unit 6, the first circuit comprises a compressor 1, a four-way valve 12, an outdoor heat exchanger 2 and an indoor heat exchanger 13, two interfaces of the four-way valve 12 are connected to the interfaces of one side of the outdoor heat exchanger 2 and one side of the indoor heat exchanger 13 respectively through pipelines, the other two interfaces of the four-way valve 12 are connected to the outlet and inlet of the compressor 1 through pipelines respectively, and the other side interfaces of the outdoor heat exchanger 2 and the indoor heat exchanger 13 are connected through pipelines, thereby forming a circuit for heat pump refrigerant circulation. In heating mode, the outdoor heat exchanger 2 serves as an evaporator and the indoor heat exchanger serves as a condenser; in low temperature environment, when the outdoor heat exchanger 2 is frosted, the flow direction of the refrigerant in the four-way valve 12 is switched, so that the outdoor heat exchanger 2 becomes a condenser to improve the temperature for defrosting. The energy storage tank 7 is provided with a first liquid inlet 71, a first liquid outlet 72, a second liquid inlet 73 and a second liquid outlet 74 which are in communication with the inside of the energy storage tank 7, and the inside of the energy storage tank 7 stores heat exchange liquid. The second circuit comprises a first electromagnetic valve 8, a first water pump 9 and a second electromagnetic valve 10. The first liquid outlet 72, the first electromagnetic valve 8, the first water pump 9, the second electromagnetic valve 10 and the first liquid inlet 71 are connected in sequence through pipelines, and a part of the pipeline between the first water pump 9 and the second electromagnetic valve 10 is wound around the surface of the compressor 1, thereby forming a heat exchange liquid heating circuit for delivering the heat exchange liquid to the surface of the compressor 1 for heating and returning to the energy storage tank 7. The third circuit comprises a third electromagnetic valve 11, a heat exchanger 3, a fourth electromagnetic valve 4 and a second water pump 5, the second liquid outlet 74, the third electromagnetic valve 11, the heat exchanger 3, the fourth electromagnetic valve 4, the second water pump 5 and the second liquid inlet 73 are connected in sequence through pipelines, the heat exchanger 3 is connected with the outdoor heat exchanger 2 to exchange heat, heat the outdoor heat exchanger 2, thereby forming a defrosting circuit for delivering the heat exchange liquid to the outdoor heat exchanger 2 for defrosting and returning to the energy storage tank 7. The heat exchange liquid flows out of the energy storage tank 7, is pumped to the pipeline wound around the surface of the compressor 1 in sequence through the first electromagnetic valve 8 and the first water pump 9, and then flows back to the energy storage tank 7 through the second electromagnetic valve 10, the heat exchange liquid flowing in the pipeline absorbs the heat generated in the working process of the compressor 1 and is stored in the energy storage tank 7; in the third circuit, the energy storage tank 7 delivers the heat exchange liquid with a certain amount of heat to the heat exchanger 3, the heat exchanger 3 is close to and contacts with the outdoor heat exchanger 2, the heat exchanger 3 exchanges heat with the outdoor heat exchanger 2, the heat exchange liquid flows out of the energy storage tank 7, flows to the heat exchanger 3 through the third electromagnetic valve 11, and then flows back to the energy storage tank in sequence through the fourth electromagnetic valve 4 and the second water pump 5.

[0023] The control unit 6 is electrically connected with the first electromagnetic valve 8, the second electromagnetic valve 10, the third electromagnetic valve 11, the fourth electromagnetic valve 4, the first water pump 9, the second water pump 5 and the four-way valve 12 respectively, and controls the opening and closing of them.

[0024] When the first electromagnetic valve 8, the second electromagnetic valve 10 and the first water pump 9 are opened, and the third electromagnetic valve 11, the fourth electromagnetic valve 4 and the second water pump 5 are closed, the second circuit is operated and the third circuit is disconnected. The first water pump 9 pumps the heat exchange liquid from the energy storage tank 7 to the surface of the compressor 1 through the first liquid outlet 72, absorbs the heat generated in the working process of the compressor 1, and the heated heat exchange liquid returns to the energy storage tank 7 through the first liquid inlet 71, so as to store the heat generated in the working process of the compressor 1 in the energy storage tank 7.

[0025] When the first water pump 9, the second water pump 5, the first electromagnetic valve 8, the second electromagnetic valve 10, the third electromagnetic valve 11 and the fourth electromagnetic valve 4 are opened at the same time, the second circuit and the third circuit are operated at the same time, and the first water pump 9 and the second water pump 5 pump the heat exchange liquid from the energy storage tank 7 to the surface of the compressor 1 through the first liquid outlet 72, absorb the heat generated in the working process of the compressor 1, and the heated heat exchange liquid is pumped back to the energy storage tank 7 through the first liquid inlet 71, and the heated heat exchange liquid is transported from the energy storage tank 7 to the heat exchanger 3 through the second liquid outlet 74, and the outdoor heat exchanger 2 is heated, and then the heat exchange liquid flows back to the energy storage tank 7 through the second liquid inlet 73.

[0026] Further, the control unit 6 comprises a temperature sensor and a timer; the temperature sensor detects the temperature C of the heat exchange liquid in the energy storage tank 7, the ambient temperature T and the temperature of the outdoor heat exchanger respectively, and the timer detects the operation time T of the first circuit of the compressor heat recovery system during heating.

[0027] Please refer to Figures 1-3 , the control method of the heat pump device comprises the following steps:

[0028] S10: The heat pump device is powered on, the first circuit is heated, and the outdoor heat exchanger is used as an evaporator.

[0029] S20: After the first circuit is heated, the second circuit is operated to heat the heat exchange liquid.

[0030] The first electromagnetic valve 8, the second electromagnetic valve 10 and the first water pump 9 are opened, the second circuit is operated, and the first water pump 9 pumps the heat exchange liquid from the energy storage tank 7 to the surface of the compressor 1 through the first liquid outlet 72 to absorb the heat generated in the working process of the compressor 1. The heated heat exchange liquid returns to the energy storage tank 7 through the first liquid inlet 71 to store the heat generated in the working process of the compressor 1 in the energy storage tank 7.

[0031] S30: Obtain the ambient temperature T and the set ambient temperature C1 and compare them.

[0032] The set ambient temperature C1 is a frosting threshold value. When the ambient temperature T is less than the set ambient temperature C1, the outdoor heat exchanger 2 is prone to frosting during operation, which is an empirical value. In this embodiment, the set ambient temperature C1 is set to 7℃.

[0033] S40: If the ambient temperature T is not less than the set ambient temperature C1, obtain the heat exchange liquid temperature C in the energy storage tank 7 and the set temperature C2, and compare to determine whether to operate the third circuit. Including the following steps:

[0034] S41: If the heat exchange liquid temperature C is not less than the set temperature C2, operate the third circuit. Until the heat exchange liquid temperature C is less than the set temperature C2, the third circuit is disconnected, and the step S40 is returned.

[0035] The first electromagnetic valve 8, the second electromagnetic valve 10, the first water pump 9, the third electromagnetic valve 11, the fourth electromagnetic valve 4 and the second water pump 5 are opened at the same time. The first water pump 9 and the second water pump 5 pump the heat exchange liquid from the energy storage tank 7 to the surface of the compressor 1 through the first liquid outlet 72 to absorb the heat generated in the working process of the compressor 1. The heated heat exchange liquid is pumped back to the energy storage tank 7 through the first liquid inlet 71. The heated heat exchange liquid is delivered from the energy storage tank 7 to the heat exchanger 3 through the second liquid outlet 74 to heat the outdoor heat exchanger 2. Then the heat exchange liquid flows back to the energy storage tank 7 through the second liquid inlet 73 until the heat exchange liquid temperature C is less than the set temperature C2.

[0036] In one embodiment, the second circuit and the third circuit are operated at the same time. In another embodiment, when the third circuit is operated, the second circuit is disconnected; when the third circuit is closed, the second circuit is operated, and the third circuit and the second circuit are independently operated separately.

[0037] S42: If the temperature C of the heat exchange liquid is less than the set temperature C2, the third circuit is not operated, and the step S40 is returned.

[0038] S50: If the ambient temperature T is less than the set ambient temperature C1, then the heat transfer liquid temperature C in the energy storage tank 7 and / or the first circuit running time T is obtained, and it is determined whether to run the third circuit or switch the four-way valve direction according to the heat transfer liquid temperature C and the first circuit running time T. The following steps are included:

[0039] S51: If the heat transfer liquid temperature C is not less than the set temperature C2 and / or the first circuit running time T is not greater than the set time T1, then the third circuit is run until the heat transfer liquid temperature C is less than the set temperature C2, the third circuit is disconnected, and step S52 is performed.

[0040] S52: After disconnecting the third circuit, the first circuit running time and the set time are compared, and if the first circuit running time T is greater than the set time T1, step S53 is performed, otherwise step S50 is returned.

[0041] The set time T1 is the time when frost is likely to occur after the first circuit is continuously running, which is an empirical value.

[0042] S53: The four-way valve direction is switched, and defrosting is performed through the first circuit.

[0043] At this time, the outdoor heat exchanger 2 acts as a condenser, and the outdoor heat exchanger 2 is defrosted by the compressor 1.

[0044] S54: After defrosting is completed, the four-way valve direction is switched, the first circuit is heated, and step S50 is performed again.

[0045] During defrosting, by detecting the temperature of the outdoor heat exchanger 2, when the outdoor heat exchanger reaches a set defrosting temperature, defrosting is ended, the four-way valve 12 is switched again, the outdoor heat exchanger 2 acts as an evaporator, and the first circuit is heated. The set defrosting temperature is greater than or equal to the set ambient temperature C1.

[0046] The heat pump device and the control method thereof of the present application carry out different operation modes according to different ambient temperatures; the heat generated in the operation of the compressor 1 is stored in the energy storage tank 7 by the heat exchange liquid, so as to avoid waste of energy; the heat of the energy storage tank 7 is delivered to the heat exchanger 3 and the outdoor heat exchanger 2 to carry out heat exchange, when the operation is carried out in the environment temperature without frost, the temperature drop rate of the outdoor heat exchanger 2 is slowed down or the temperature of the outdoor heat exchanger is increased, so as to improve the operation efficiency, when the operation is carried out in the low temperature environment, the outdoor heat exchanger 2 is not frosted, the defrosting interval is prolonged, the defrosting frequency is reduced, and the capacity energy efficiency of the system is greatly improved. The opening of the four-way valve 12 is controlled by detecting the internal temperature of the energy storage tank 7 and the operation time of the machine when the defrosting is required, so as to ensure the defrosting effect of the unit when the heat of the energy storage tank 7 is insufficient. The switching of different operation modes is carried out by detecting the change of the ambient temperature.

[0047] The above-mentioned embodiments only express several embodiments of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the scope of the patent application. It should be pointed out that, for the ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, and the present application also intends to include these modifications and improvements.

Claims

1. A control method for a heat pump device, characterized in that: The heat pump unit includes a first circuit, a second circuit, a third circuit, an energy storage tank, and a control unit. The first circuit is used for heat pump refrigerant circulation and includes a compressor, an outdoor heat exchanger, and a four-way valve. The energy storage tank is used to store the heat exchange fluid. The second circuit is used to deliver the heat exchange fluid to the surface of the compressor for heating and then return it to the energy storage tank. The third circuit is used to deliver the heat exchange fluid to the outdoor heat exchanger for defrosting and then return it to the energy storage tank. The control unit is electrically connected to the first circuit, the second circuit, and the third circuit respectively, and controls their on / off states. The heat pump device control method is carried out in the above-mentioned heat pump device and includes the following steps: The first loop is operated, with the outdoor heat exchanger acting as an evaporator; After the first circuit begins heating, the second circuit is then activated. Acquire and set the ambient temperature, and compare them; If the ambient temperature is not lower than the set ambient temperature, then the temperature of the heat exchange fluid in the energy storage tank and the set temperature are obtained and compared to determine whether the third loop should be operated. If the ambient temperature is lower than the set ambient temperature, the temperature of the heat exchange fluid in the energy storage tank and / or the running time of the first loop are obtained, and the third loop is run or the four-way valve direction is switched based on the temperature of the heat exchange fluid and the running time of the first loop. The set time is the time when frost occurs after the first circuit has been running continuously; If the heat exchange fluid temperature is not less than the set temperature and / or the first loop operation time is not greater than the set time, then the third loop is operated until the heat exchange fluid temperature is less than the set temperature, then the third loop is disconnected.

2. The heat pump device control method according to claim 1, characterized in that: The control unit includes a temperature sensor and a timer; the temperature sensor detects the temperature of the heat exchange fluid inside the energy storage tank and the ambient temperature, and the timer detects the running time of the first circuit during heating.

3. The heat pump device control method according to claim 1, characterized in that: The first circuit also includes an indoor heat exchanger. Two ports of the four-way valve are connected to the ports on the outdoor heat exchanger and the indoor heat exchanger via pipelines, respectively. The other two ports of the four-way valve are connected to the outlet and inlet of the compressor via pipelines, respectively. The other ports of the outdoor heat exchanger and the indoor heat exchanger are connected via pipelines.

4. The heat pump device control method according to claim 1, characterized in that: Obtaining the temperature of the heat exchange fluid in the energy storage tank and the set temperature, and comparing them to determine whether to operate the third loop, includes the following steps: If the temperature of the heat exchange fluid is not lower than the set temperature, the third circuit is operated until the temperature of the heat exchange fluid is lower than the set temperature, at which point the third circuit is disconnected. If the temperature of the heat exchange fluid is lower than the set temperature, the third circuit will not operate.

5. The heat pump device control method according to claim 1, characterized in that: Obtaining the temperature of the heat exchange fluid in the energy storage tank and / or the operating time of the first loop, and determining whether to operate the third loop or switch the direction of the four-way valve based on the temperature of the heat exchange fluid and the operating time of the first loop, includes the following steps: During the defrosting process, the temperature of the outdoor heat exchanger is detected. When the outdoor heat exchanger reaches the set defrosting temperature, the defrosting ends, the direction of the four-way valve is switched, and the outdoor heat exchanger is used as a condenser. After a period of defrosting, defrosting is complete. The direction of the four-way valve is switched, and the outdoor heat exchanger is used as an evaporator.

6. The heat pump device control method according to claim 1, characterized in that: The second circuit and the third circuit operate simultaneously; or when the third circuit is running, the second circuit is disconnected, and when the third circuit is closed, the second circuit is running, and the third circuit and the second circuit operate independently.

7. The heat pump device control method according to claim 1, characterized in that: The set ambient temperature is the temperature threshold at which the outdoor heat exchanger will frost during operation.

8. The heat pump device control method according to claim 5, characterized in that: The set defrost temperature is greater than or equal to the set ambient temperature.

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