Waste heat recovery auxiliary defrosting system and method

Abstract

The embodiment of the invention discloses a waste heat recovery auxiliary defrosting system and method. The system comprises a waste heat recovery module and at least one heat pump unit, and each heat pump unit comprises a compressor, an exhaust pipeline, a switch module and an evaporator; the exhaust pipeline is connected with an exhaust port of the compressor, the waste heat recovery module is arranged at the exhaust pipeline and / or the exhaust port of the compressor, and the waste heat recovery module is used for absorbing and storing heat of gas exhausted by the compressor; and the switch module is connected with the waste heat recovery module and the evaporator, and the switch module is configured to transmit heat stored by the waste heat recovery module to the evaporator when the waste heat recovery module communicates with the evaporator so as to defrost the evaporator. Waste heat is used for replacing traditional electric heating or reverse circulation defrosting, comprehensive defrosting energy consumption is reduced, shutdown is not needed in the defrosting period, temperature fluctuation is reduced, frequent starting and stopping of a compressor and loss of an electric heating element are reduced, and the energy utilization efficiency and environment friendliness of the system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump systems, and in particular to a waste heat recovery auxiliary defrosting system and method. Background Art

[0002] In an air source heat pump system, when the evaporator surface temperature is lower than the dew point temperature of the ambient air, the moisture in the air will condense into frost. Frosting will increase the wind resistance of the outdoor unit. Thick frost will cause the evaporator fins to deform and the pipes to clog. In severe cases, the heat exchange tubes may collapse. Evaporator blockage forces the system to start and stop frequently, shortening the life of the equipment.

[0003] At present, traditional electric heating or reverse cycle is mainly used for defrosting. The energy consumption of traditional electric heating defrosting accounts for 10%-20% of the total energy consumption of the system. In addition, the local temperature rises suddenly during electric heating defrosting, which is easy to damage the evaporator fins or coating, reducing the life of the equipment. Reverse cycle defrosting leads to heating interruption and frequent start and stop losses of the compressor. Summary of the invention

[0004] The present invention provides a waste heat recovery auxiliary defrosting system and method to solve the problems of high energy consumption, low waste heat utilization rate and large temperature fluctuation in the existing defrosting technology.

[0005] The present invention provides a waste heat recovery auxiliary defrosting system, comprising a waste heat recovery module and at least one heat pump unit, wherein the heat pump unit comprises a compressor, an exhaust pipe, a switch module and an evaporator;

[0006] The exhaust pipe is connected to the exhaust port of the compressor, the waste heat recovery module is placed at the exhaust pipe and / or the exhaust port of the compressor, and the waste heat recovery module is used to absorb and store the heat of the exhaust gas of the compressor;

[0007] The switch module is connected to the waste heat recovery module and the evaporator respectively, and is configured to transfer the heat stored in the waste heat recovery module to the evaporator when the waste heat recovery module and the evaporator are connected, so as to defrost the evaporator.

[0008] Optionally, the waste heat recovery module includes a heat pipe unit and a phase change heat storage unit;

[0009] The heat pipe unit is placed on the outer wall of the exhaust pipe of the compressor, and the heat pipe unit is used to absorb the heat of the exhaust gas of the compressor;

[0010] The phase-change heat storage unit is respectively connected to the heat pipe unit and the switch module, and the phase-change heat storage unit is used to store the heat of the exhaust gas of the compressor.

[0011] Optionally, it further includes a control module, a first temperature detection module and a second temperature detection module, wherein the control module is respectively connected to the first temperature detection module, the second temperature detection module and the switch module, and the first temperature detection module is used to detect the heat storage temperature of the phase change heat storage unit;

[0012] The second temperature detection module is used to detect the surface temperature of the evaporator;

[0013] The control module is used to control the switch module to transfer the heat stored in the waste heat recovery module to the evaporator to defrost the evaporator when determining that the evaporator needs to be defrosted according to the temperatures detected by the first temperature detection module and the second temperature detection module.

[0014] Optionally, the heat pump unit also includes an electric heating auxiliary module, which is connected to the control module. The control module is also used to control the start-up of the electric heating auxiliary module as a supplement to defrost the evaporator when the temperature detected by the first temperature detection module is lower than a first preset temperature and / or when the temperature detected by the second temperature detection module is lower than a second preset temperature after the waste heat recovery module and the evaporator are connected for a preset time.

[0015] Optionally, the switch module includes a three-way solenoid valve;

[0016] The three-way solenoid valve has a first port, a second port and a third port, the first port is connected to the outlet of the phase change heat storage unit through a pipeline, the second port is connected to the condenser, and the third port is connected to the evaporator through a pipeline;

[0017] The control module is used to control the first port and the third port of the three-way solenoid valve to be connected when it is detected that the evaporator needs to be defrosted, so as to transfer the heat stored in the waste heat recovery module to the evaporator;

[0018] The control module is also used to control the first port to be connected to the second port when the temperature detected by the second temperature detection module is greater than a second preset temperature, so as to transfer the heat stored in the waste heat recovery module to the condenser.

[0019] Optionally, the heat pump unit further comprises a condenser, and the condenser is connected to the exhaust pipe;

[0020] The control module is also used to control the gas discharged from the exhaust pipe to be transmitted from the evaporator to the condenser and then to the compressor through the air intake pipe of the compressor when the temperature detected by the first temperature detection module is lower than a first preset temperature and / or when the temperature detected by the second temperature detection module is lower than a second preset temperature after the waste heat recovery module and the evaporator are connected for a preset time.

[0021] Optionally, the heat pump unit further includes a four-way valve, the four-way valve includes a fourth port, a fifth port, a sixth port and a seventh port, the fourth port is connected to the exhaust pipe, the fifth port is connected to the evaporator, the sixth port is connected to the compressor through a pipeline, and the seventh port is connected to the condenser through a pipeline;

[0022] The control module is also used to control the fourth and fifth ports of the four-way valve to be connected, and after the gas discharged from the exhaust pipe is transferred from the evaporator to the condenser, control the sixth and seventh ports of the four-way valve to be connected, and transfer the gas to the compressor through the air intake pipe of the compressor, when the temperature detected by the first temperature detection module is lower than a first preset temperature, and / or when the temperature detected by the second temperature detection module is lower than a second preset temperature after the waste heat recovery module and the evaporator are connected for a preset time.

[0023] Optionally, at least two heat pump units are included, the waste heat recovery module includes at least two heat pipe units, and the heat pipe units are arranged on the outer wall of the exhaust pipe of the compressor in a one-to-one correspondence;

[0024] The control module is used to determine the heat pump unit with the lowest evaporator temperature among at least two heat pump units according to the temperatures detected by each of the second temperature detection modules, and control the switch module in the heat pump unit with the lowest evaporator temperature to preferentially transfer the stored heat to the evaporator. After the heat pump unit with the lowest evaporator temperature is defrosted preferentially, the evaporators of other heat pump units are controlled to be defrosted.

[0025] According to another aspect of the present invention, a waste heat recovery assisted defrosting method is provided, which adopts the waste heat recovery assisted defrosting system described in any of the above embodiments, comprising:

[0026] When the evaporator needs to be defrosted, the switch module is controlled to connect the waste heat recovery module and the evaporator, and the heat stored in the waste heat recovery module is transferred to the evaporator to defrost the evaporator.

[0027] Optionally, when the evaporator needs to be defrosted, controlling the switch module to connect the waste heat recovery module with the evaporator, and transferring the heat stored in the waste heat recovery module to the evaporator to defrost the evaporator, including:

[0028] When it is determined that the evaporator needs to be defrosted according to the heat storage temperature of the waste heat recovery module detected by the first temperature detection module and the surface temperature of the evaporator detected by the second temperature detection module, the switch module is controlled to transfer the heat stored in the waste heat recovery module to the evaporator to defrost the evaporator;

[0029] When the temperature detected by the first temperature detection module is lower than a first preset temperature, and / or when the temperature detected by the second temperature detection module is lower than a second preset temperature after the waste heat recovery module and the evaporator are connected for a preset time, the electric heating auxiliary module is controlled to be started and / or the gas discharged from the exhaust pipe is controlled to be transmitted from the evaporator to the condenser and then transmitted to the compressor through the air intake pipe of the compressor to defrost the evaporator.

[0030] The technical solution of the embodiment of the present invention can reduce energy waste by arranging a waste heat recovery module at the position of the exhaust pipe and / or exhaust port of the compressor to absorb and store the heat of the exhaust gas of the compressor. When the evaporator needs to be defrosted, the waste heat recovery module and the evaporator are connected through the switch module, and the heat stored in the waste heat recovery module is transmitted to the evaporator to achieve defrosting of the evaporator. The technical solution of the embodiment of the present invention uses waste heat to replace traditional electric heating or reverse cycle defrosting, which reduces the comprehensive defrosting energy consumption, does not require shutdown during defrosting, reduces temperature fluctuations, reduces frequent start and stop of the compressor and loss of electric heating elements, and improves the energy utilization efficiency and environmental friendliness of the system.

[0031] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 1 is a schematic structural diagram of a waste heat recovery auxiliary defrosting system provided by an embodiment of the present invention;

[0034] Figure 2 is a structural schematic diagram of another waste heat recovery auxiliary defrosting system provided by an embodiment of the present invention;

[0035] Figure 3 is a structural schematic diagram of another waste heat recovery auxiliary defrosting system provided by an embodiment of the present invention;

[0036] Figure 4 This is a structural block diagram of a waste heat recovery auxiliary defrosting system provided by an embodiment of the present invention;

[0037] Figure 5 It is a structural schematic diagram of the flow direction of the refrigerant during the heating cycle;

[0038] Figure 6 It is a structural diagram of the defrost cycle and the flow direction of the refrigerant;

[0039] Figure 7 is a structural schematic diagram of a waste heat recovery auxiliary defrosting system of a multi-heat pump unit provided by an embodiment of the present invention;

[0040] Figure 8 This is a structural block diagram of a waste heat recovery auxiliary defrosting system for a multi-heat pump unit provided by an embodiment of the present invention;

[0041] Fig. 9 This is a flow chart of a waste heat recovery auxiliary defrosting method provided by an embodiment of the present invention;

[0042] Fig.10 The present invention provides another waste heat recovery auxiliary defrosting method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0044] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0045] Figure 1 This is a schematic diagram of the structure of a waste heat recovery auxiliary defrosting system provided by an embodiment of the present invention. This embodiment can be applied to refrigeration, heating and dehumidification equipment that requires defrosting, such as air conditioning systems, cold storage equipment, food processing, and pharmaceutical production in cold northern regions. Figure 1As shown, the system includes: a waste heat recovery module 101, at least one heat pump unit 10, the heat pump unit 10 includes a compressor 102, an exhaust pipe 103, a switch module 104 and an evaporator 105;

[0046] The exhaust pipe 103 is connected to the exhaust port of the compressor 102, and the waste heat recovery module 101 is placed at the exhaust pipe 103 and / or the exhaust port of the compressor 102. The waste heat recovery module 101 is used to absorb and store the heat of the exhaust gas of the compressor 102;

[0047] The switch module 104 is connected to the waste heat recovery module 101 and the evaporator 105 respectively. The switch module 104 is configured to transfer the heat stored in the waste heat recovery module 101 to the evaporator 105 when the waste heat recovery module 101 and the evaporator 105 are connected to defrost the evaporator 105 .

[0048] Among them, the compressor 102 can compress the refrigerant vapor and discharge high-temperature and high-pressure gas. The exhaust temperature of the compressor is usually high, for example, the exhaust temperature is greater than 50°C, or even as high as 80-100°C. If the heat is directly dissipated to the environment through the condenser, energy loss will be caused. In traditional systems, direct discharge is mostly used, resulting in energy waste and environmental problems. In this embodiment, the waste heat recovery module 101 is placed at the exhaust pipe 103 and / or the exhaust port of the compressor 102, which can absorb the heat of the exhaust gas of the compressor 102 and store it, which can be used to assist defrosting in the defrosting system. In this way, energy waste can be reduced, and the energy utilization efficiency and environmental friendliness of the system can be improved. When the system is running, the surface temperature of the evaporator 105 is low, and the water vapor in the air will condense into frost, affecting the heat exchange efficiency and system performance of the evaporator 105. In order to maintain the efficient operation of the system, regular defrosting operations are required. When the evaporator 105 needs to be defrosted, the switch module 104 can be turned on to connect the waste heat recovery module 101 and the evaporator 105. Among them, the switch module 104 can include a valve, such as a solenoid valve or a mechanical valve. After the switch module 104 is turned on, the heat stored in the waste heat recovery module 101 will be released, and the heat will be transferred to the evaporator 105 through the switch module 104. The frost layer on the surface of the evaporator 105 absorbs the heat and begins to melt, thereby achieving defrosting. The waste heat of the compressor is utilized, which reduces the system's dependence on external heat sources, reduces energy consumption, and ensures the continuous and stable operation of the heat pump system.

[0049] The technical solution of the embodiment of the present invention can reduce energy waste by arranging a waste heat recovery module at the position of the exhaust pipe and / or exhaust port of the compressor to absorb and store the heat of the exhaust gas of the compressor. When the evaporator needs to be defrosted, the waste heat recovery module and the evaporator are connected through the switch module, and the heat stored in the waste heat recovery module is transmitted to the evaporator to achieve defrosting of the evaporator. The technical solution of the embodiment of the present invention uses waste heat to replace electric heating, which reduces the comprehensive defrosting energy consumption. There is no need to shut down during defrosting, which reduces temperature fluctuations, reduces the frequent start and stop of the compressor and the loss of electric heating elements, and improves the energy utilization efficiency and environmental friendliness of the system.

[0050] Figure 2 is a schematic diagram of the structure of another waste heat recovery auxiliary defrosting system provided by an embodiment of the present invention. In some optional embodiments of the present invention, such as Figure 2 As shown, the waste heat recovery module 101 includes a heat pipe unit 1011 and a phase change heat storage unit 1012;

[0051] The heat pipe unit 1011 is placed on the outer wall of the exhaust pipe 103 of the compressor 102, and the heat pipe unit 1011 is used to absorb the heat of the exhaust gas of the compressor 102;

[0052] The phase change heat storage unit 1012 is connected to the heat pipe unit 1011 and the switch module 104 respectively, and the phase change heat storage unit 1012 is used to store the heat of the compressor exhaust gas.

[0053] Among them, the heat pipe unit 1011 may include multiple heat pipes, and multiple heat pipes are arranged in an array. In some embodiments, multiple heat pipes are closely arranged. The heat pipe unit 1011 can efficiently conduct heat and is used to transfer the heat of the exhaust gas of the compressor 102. The heat pipe unit 1011 is arranged on the outer wall of the exhaust pipe 103 of the compressor 102. When the compressor 102 discharges high-temperature and high-pressure gas, the heat pipe unit 1011 absorbs and transmits the heat of the exhaust gas of the compressor 102, and transfers the heat from one end of the heat pipe to the other end. The phase change heat storage unit 1012 has a built-in phase change material, which uses the phase change material to change the state of matter with temperature changes, such as solid to liquid, and can complete the heat storage through the characteristics of latent heat, and the temperature change is relatively small, which buffers the temperature fluctuation. The heat transferred from the heat pipe unit 1011 is absorbed by the phase change heat storage unit 1012. The phase change material undergoes a phase change when absorbing this heat, and stores the heat in the form of latent heat. The phase change heat storage unit 1012 can not only store a large amount of heat, but also keep the temperature relatively stable during the storage process. When it is necessary to release heat, the phase change material can quickly reverse phase change, such as changing from liquid to solid, to release the stored heat.

[0054] In some optional embodiments of the present invention, continue to refer to Figure 2The waste heat recovery auxiliary defrosting system also includes a control module 106, a first temperature detection module 107 and a second temperature detection module 108. The control module 106 is connected to the first temperature detection module 107, the second temperature detection module 108 and the switch module 104 respectively. The first temperature detection module 107 is used to detect the heat storage temperature of the phase change heat storage unit 1012.

[0055] The second temperature detection module 108 is used to detect the surface temperature of the evaporator 105;

[0056] The control module 106 is used to control the switch module 104 to transfer the heat stored in the waste heat recovery module 101 to the evaporator 105 to defrost the evaporator 105 when determining that the evaporator 105 needs to be defrosted according to the temperatures detected by the first temperature detection module 107 and the second temperature detection module 108.

[0057] Among them, the first temperature detection module 107 and the second temperature detection module 108 can use temperature sensors. The first temperature detection module 107 detects the heat storage temperature of the phase change heat storage unit 1012, and can monitor the heat storage temperature of the phase change heat storage unit 1012. The second temperature detection module 108 detects the temperature of the surface of the evaporator 105, and can timely find out that the surface temperature of the evaporator 105 is too low or frosting occurs. The control module 106 can obtain the temperature data of the first temperature detection module 107 and the second temperature detection module 108 in real time to determine whether the evaporator 105 needs to be defrosted. When the surface temperature of the evaporator 105 is too low and the heat storage temperature of the phase change heat storage unit 1012 is sufficient, the control module 106 controls the switch module 104 to open, and transfers the heat stored in the waste heat recovery module 101 to the evaporator 105, and uses the waste heat to remove the frost layer on the surface of the evaporator 105.

[0058] Specifically, the evaporator 105 needs to be defrosted if the coil temperature of the evaporator is lower than the third preset temperature within the first preset time, and / or the difference between the ambient temperature and the evaporator fin temperature meets the preset difference after the second preset time after defrosting is completed, and / or the difference between the ambient temperature and the evaporator fin temperature increases by the fourth preset temperature within the third preset time. Exemplarily, the first preset time and the second preset time may be 40 minutes, the third preset temperature may be 0°C, the preset difference may be 7°C, the third preset time may be 5 minutes, and the fourth preset temperature may be 2°C. That is, if the coil temperature of the evaporator is lower than 0°C within 40 minutes, and / or the difference between the ambient temperature and the evaporator fin temperature meets 7°C 40 minutes after defrosting is completed, and / or the difference between the ambient temperature and the evaporator fin temperature increases by 2°C within 5 minutes, the evaporator 105 needs to be defrosted.

[0059] In some optional embodiments of the present invention, continue to refer to Figure 2The heat pump unit 10 also includes an electric heating auxiliary module 109, which is connected to the control module 106. The control module 106 is also used to control the start of the electric heating auxiliary module 109 as a supplement to defrost the evaporator 105 when the temperature detected by the first temperature detection module 107 is lower than the first preset temperature and / or when the temperature detected by the second temperature detection module 108 is lower than the second preset temperature after the waste heat recovery module 101 and the evaporator 105 are connected for a preset time.

[0060] Among them, the electric heating auxiliary module 109 can be set on the surface of the evaporator 105, mainly used to remove the frost layer on the surface of the evaporator 105 to maintain the efficient operation of the system. When defrosting is required, the electric heating element starts to work and generates heat. The heat generated by the electric heating element is transferred to the surface of the evaporator by heat conduction, so that the frost layer gradually melts into water. The first preset temperature is the temperature threshold of the waste heat recovery module 101 for defrosting. When the heat storage temperature of the waste heat recovery module 101 is less than the first preset temperature, it means that the heat stored in the waste heat recovery module 101 cannot complete the defrosting of the evaporator 105. The preset time refers to the time threshold for defrosting using the stored heat of the waste heat recovery module 101. The second preset temperature refers to the temperature threshold for defrosting on the evaporator surface. After the waste heat recovery module 101 and the evaporator 105 are connected for a preset time, when the temperature detected by the second temperature detection module 108 is less than the second preset temperature, it also means that the heat stored in the waste heat recovery module 101 cannot complete the defrosting of the evaporator 105. At this time, the control module 106 may start the electric heating auxiliary module 109 to defrost the evaporator 105 .

[0061] For example, the first preset temperature may be 55°C. When the heat stored in the waste heat recovery module 101 is less than 55°C, the electric heating auxiliary module 109 may be controlled to be started as a supplement to defrost the evaporator 105. The preset time may be 5 minutes, and the second preset temperature may be 5°C. When the surface temperature of the evaporator 105 is less than 5°C after the evaporator 105 is defrosted for 5 minutes using the heat stored in the waste heat recovery module 101, the electric heating auxiliary module 109 may be controlled to be started as a supplement to defrost the evaporator 105.

[0062] The technical solution of the embodiment of the present invention detects the temperature of the phase change heat storage unit and the surface of the evaporator through the first temperature detection module and the second temperature detection module. The heat storage temperature in the phase change heat storage unit can be monitored, and it can be found that the surface temperature of the evaporator is too low and frosting may occur. The control module determines whether the evaporator needs to be defrosted based on the temperatures detected by the first temperature detection module and the second temperature detection module, and controls the switch module to transfer the heat stored in the waste heat recovery module to the evaporator to defrost the evaporator. When the heat storage temperature of the waste heat recovery module is insufficient or the defrosting completion threshold is not reached within the preset time, the electric heating auxiliary module is controlled to defrost the evaporator. Combined with the hybrid defrosting strategy of waste heat recovery module heat storage and electric heating, waste heat is used first, and when it is insufficient, the traditional electric heating defrosting method is supplemented, thereby realizing seamless switching of defrosting.

[0063] Figure 3 is a structural schematic diagram of another waste heat recovery auxiliary defrosting system provided by an embodiment of the present invention. Figure 4 is a structural block diagram of a waste heat recovery auxiliary defrosting system provided by an embodiment of the present invention. In some optional embodiments of the present invention, such as Figure 3 and Figure 4 As shown, the switch module 104 includes a three-way solenoid valve 1041;

[0064] The three-way solenoid valve 1041 has a first port A, a second port B and a third port C. The first port A is connected to the outlet of the phase change heat storage unit 1012 through a pipeline, the second port B is connected to the condenser 110, and the third port C is connected to the evaporator 105 through a pipeline.

[0065] The control module 106 is used to control the first port A and the third port C of the three-way solenoid valve 1041 to be connected when it is detected that the evaporator 105 needs to be defrosted, so as to transfer the heat stored in the waste heat recovery module 101 to the evaporator 105;

[0066] The control module 106 is further configured to control the first port A and the second port B to be connected when the temperature detected by the second temperature detection module 108 is greater than a second preset temperature, so as to transfer the heat stored in the waste heat recovery module 101 to the condenser 110 .

[0067] Among them, the three-way solenoid valve 1041 uses electromagnetic principles to control the valve that switches between three channels of fluids, such as gas, liquid, etc. When it is detected that the evaporator 105 needs to be defrosted, the control module 106 can control the waste heat recovery module 101 to be connected with the evaporator 105, that is, the first port A is connected with the second port B, and the heat stored in the waste heat recovery module 101 is transmitted to the evaporator 105 to defrost the evaporator 105. When the surface temperature of the evaporator is greater than the second preset temperature, it indicates that the defrosting of the evaporator 105 is completed. At this time, the control module 106 can control the waste heat recovery module 101 to be connected with the condenser 110, that is, the first port A is connected with the third port C, and the heat stored in the waste heat recovery module 101 is transmitted to the condenser 110 for heat dissipation.

[0068] In some optional embodiments of the present invention, continue to refer to Figure 3 , the heat pump unit 10 further includes a condenser 110, and the condenser 110 is connected to the exhaust pipe 103;

[0069] The control module 106 is also used to control the gas discharged from the exhaust pipe 103 to be transmitted from the evaporator 105 to the condenser 110, and then to the compressor 102 through the air intake pipe of the compressor 102 when the temperature detected by the first temperature detection module 107 is lower than the first preset temperature and / or when the temperature detected by the second temperature detection module 108 is lower than the second preset temperature after the waste heat recovery module 101 and the evaporator 105 are connected for a preset time.

[0070] Among them, reverse cycle defrosting refers to the technology of performing defrosting operation by changing the flow direction of refrigerant in the refrigeration system. In the conventional refrigeration or heating mode, the refrigerant flows according to a certain circulation path, and in the defrosting mode, the flow direction of the refrigerant is changed by controlling the switching of valves and other components, thereby realizing the defrosting function. The condenser 110 can condense the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 102 into a liquid state, thereby realizing the refrigeration cycle. When the heat storage temperature of the waste heat recovery module 101 is insufficient or the defrosting completion threshold is not reached within the preset time, the control module 106 can control the gas discharged from the exhaust pipe 103 to be transmitted from the evaporator 105 to the condenser 110, and then transmitted to the compressor 102 through the air intake pipe of the compressor 102. During the reverse cycle, the surface temperature of the evaporator 105 increases, and the heat is transferred to the frosted surface of the evaporator 105, so that the frost layer gradually melts.

[0071] In some optional embodiments of the present invention, continue to refer to Figure 3 The heat pump unit 10 further includes a four-way valve 111, which includes a fourth port D, a fifth port E, a sixth port E and a seventh port G. The fourth port D is connected to the exhaust pipe 103, the fifth port E is connected to the evaporator 105, the sixth port F is connected to the compressor 102 through a pipeline, and the seventh port G is connected to the condenser 110 through a pipeline;

[0072] The control module 106 is also used to control the fourth port D and the fifth port E of the four-way valve 111 to be connected when the temperature detected by the first temperature detection module 107 is lower than the first preset temperature and / or when the temperature detected by the second temperature detection module 108 is lower than the second preset temperature after the waste heat recovery module 101 and the evaporator 105 are connected for a preset time, so as to transfer the gas discharged from the exhaust pipe 103 from the evaporator 105 to the condenser 110, and then control the sixth port F and the seventh port G of the four-way valve 111 to be connected, and transfer the gas to the compressor 102 through the intake pipe of the compressor 102.

[0073] The four-way valve 111 has four channels, and the flow direction of the fluid in the valve is changed by the movement of the valve core. When the heat storage temperature of the waste heat recovery module 101 is insufficient or the defrosting completion threshold is not reached within the preset time, the control module 106 can control the fourth port D and the fifth port E of the four-way valve 111 to be connected, and after the gas discharged from the exhaust pipe 103 is transmitted from the evaporator 105 to the condenser 110, the sixth port F and the seventh port G of the four-way valve 111 are controlled to be connected, and transmitted to the compressor 102 through the intake pipe of the compressor 102.

[0074] Figure 5 It is a structural diagram of the flow of refrigerant during the heating cycle. Figure 6 The defrost cycle is a schematic diagram of the flow direction of the refrigerant. In the heat pump system, the four-way valve 111 is often used to control the flow direction of the refrigerant to achieve the switching between cooling and heating, or to change the flow direction of the refrigerant during the defrost process. Figure 5 As shown, in a normal heating cycle, the refrigerant flows from the exhaust pipe 103 of the compressor 102 to the condenser 110 through the four-way valve 111, and then flows from the condenser 110 to the evaporator 105 and then flows to the compressor 102 through the four-way valve 111. The refrigerant absorbs heat in the evaporator 105 and evaporates, and releases heat in the condenser 110 and condenses. In a defrosting cycle, as shown in FIG. Figure 6 As shown, the refrigerant flows from the exhaust pipe 103 of the compressor 102 to the evaporator 105 through the four-way valve 111 for defrosting, then flows to the condenser 110, and flows to the compressor 102 through the four-way valve 111. The flow direction of the refrigerant is changed by the four-way valve 111, so that the refrigerant condenses in the evaporator 105 to release heat, and evaporates in the condenser 110 to absorb heat.

[0075] The technical solution of the embodiment of the present invention realizes the connection between the waste heat recovery module and the evaporator through the electromagnetic three-way valve, and defrosts the evaporator through the heat storage of the waste heat recovery module. When the heat storage temperature of the waste heat recovery module is insufficient or the defrosting completion threshold is not reached within the preset time, the evaporator is defrosted by controlling the four-way valve using a reverse cycle. Combining the hybrid defrosting strategy of heat storage and reverse cycle of the waste heat recovery module, waste heat is used first, and when it is insufficient, the traditional reverse cycle defrosting method is supplemented, thereby realizing seamless switching of defrosting.

[0076] Figure 7 1 is a schematic structural diagram of a waste heat recovery auxiliary defrosting system for a multi-heat pump unit provided by an embodiment of the present invention. Figure 8 is a structural block diagram of a waste heat recovery auxiliary defrosting system for a multi-heat pump unit provided by an embodiment of the present invention. In some optional embodiments of the present invention, reference Figure 3 , Figure 7 and Figure 8 , including at least two heat pump units 10, the waste heat recovery module includes at least two heat pipe units 1011, and the heat pipe units 1011 are arranged one by one on the outer wall of the exhaust pipe 103 of the compressor 102;

[0077] The control module 106 is used to determine the heat pump unit 10 with the lowest evaporator 105 temperature among at least two heat pump units 10 according to the temperatures detected by each second temperature detection module 108, and control the switch module 104 in the heat pump unit 10 with the lowest evaporator 105 temperature to preferentially transfer the stored heat to the evaporator 105. After the heat pump unit 10 with the lowest evaporator 105 temperature is defrosted preferentially, the evaporators 105 of other heat pump units 10 are defrosted.

[0078] Among them, the heat pipe units 1011 are arranged one by one on the outer wall of the exhaust pipe 103 of the compressor 102. The heat pipe units 1011 can transfer the heat of the exhaust gas of the compressor 102 to the phase change heat storage unit 1012. The phase change heat storage unit 1012 is connected with at least two heat pipe units 1011, and the phase change heat storage unit 1012 can store the heat transferred by at least two heat pipe units 1011. Each second temperature detection module 107 detects the surface temperature of the evaporator 105 of at least two heat pump units 10, and determines that the heat pump unit 10 with the lowest surface temperature of the evaporator 105 is the heat pump unit 10 with priority defrosting. At this time, the corresponding control module 106 controls the switch module 104 to preferentially transfer the heat stored in the phase change heat storage unit 1011 to the evaporator 105. After the heat pump unit 10 with the lowest evaporator 105 temperature is preferentially defrosted, the evaporators 105 of other heat pump units 10 are defrosted.

[0079] The technical solution of the embodiment of the present invention is to transmit the heat of the exhaust gas of the compressor to the phase change heat storage unit through the heat pipe unit which is arranged one by one on the outer wall of the exhaust pipe of the compressor, thereby improving the energy utilization efficiency and reducing the energy consumption of the system. The heat pump unit with the lowest evaporator surface temperature is determined by each second temperature detection module, and at the same time, the corresponding control module controls the switch module to transfer the heat stored in the phase change heat storage unit to the unit with the lowest evaporator surface temperature, and defrost the evaporator of the unit. It can accurately provide heat to the unit that needs defrosting the most, improve the defrosting efficiency, and reduce the defrosting time. After defrosting is completed, the switch modules of other units are controlled to control the defrosting of the evaporators of other units. The damage to the equipment caused by frequent start and stop and low-temperature operation is reduced, the maintenance and replacement costs of the equipment are reduced, and the occurrence of the situation where the overall system performance is affected by severe frosting of individual evaporators is reduced.

[0080] Fig. 9 is a flowchart of a waste heat recovery auxiliary defrosting method provided by an embodiment of the present invention, with reference to Figure 3 and Fig. 9 , using the waste heat recovery auxiliary defrosting system of any of the above embodiments, the method comprises:

[0081] S201 . When the evaporator 105 needs to be defrosted, the switch module 104 is controlled to connect the waste heat recovery module 101 and the evaporator 105 , and the heat stored in the waste heat recovery module 101 is transferred to the evaporator 105 to defrost the evaporator 105 .

[0082] When it is detected that the evaporator 105 needs to be defrosted, the switch module 104 can connect the waste heat recovery module 101 and the evaporator 105. At this time, the heat stored in the waste heat recovery module 101 will be released and transferred to the evaporator 105. The frost layer on the surface of the evaporator 105 absorbs the heat and begins to melt, thereby achieving defrosting.

[0083] The technical solution of the embodiment of the present invention can reduce energy waste by absorbing and storing the heat of the exhaust gas of the compressor through the waste heat recovery module. When the evaporator needs to be defrosted, the waste heat recovery module and the evaporator are connected through the switch module, and the heat stored in the waste heat recovery module is transmitted to the evaporator to achieve defrosting of the evaporator. The technical solution of the embodiment of the present invention utilizes the waste heat of the compressor, reduces the system's dependence on external heat sources, reduces energy consumption, and ensures the continuous and stable operation of the heat pump system.

[0084] Fig.10 is a flow chart of another waste heat recovery auxiliary defrosting method provided by an embodiment of the present invention. In some optional embodiments of the present invention, reference Figure 3 , Fig. 9 and Fig.10When the evaporator needs to be defrosted, the control switch module connects the waste heat recovery module and the evaporator, and transmits the heat stored in the waste heat recovery module to the evaporator to defrost the evaporator, including:

[0085] S301, when it is determined that the evaporator 105 needs to be defrosted according to the heat storage temperature of the waste heat recovery module 101 detected by the first temperature detection module 107 and the surface temperature of the evaporator 105 detected by the second temperature detection module 108, the switch module 104 is controlled to transfer the heat stored in the waste heat recovery module 101 to the evaporator 105 to defrost the evaporator 105;

[0086] Among them, the first temperature detection module 107 detects the heat storage temperature of the phase change heat storage unit 1012, and can monitor the heat storage temperature of the waste heat recovery module 101. The second temperature detection module 108 detects the temperature of the surface of the evaporator 105, and can promptly find out that the surface temperature of the evaporator 105 is too low or frosting occurs. The control module 106 can obtain the temperature data of the first temperature module 107 and the second temperature detection module 108 in real time to determine whether the evaporator 105 needs to be defrosted. When the surface temperature of the evaporator 105 is too low and the heat storage temperature of the phase change heat storage module 101 is sufficient, the control module 106 controls the switch module 104 to transfer the heat stored in the waste heat recovery module 101 to the evaporator 105, and use the waste heat to remove the frost layer on the surface of the evaporator 105.

[0087] S302, when the temperature detected by the first temperature detection module 107 is lower than the first preset temperature, and / or, after the waste heat recovery module 101 and the evaporator 105 are connected for a preset time, when the temperature detected by the second temperature detection module 108 is lower than the second preset temperature, control the start of the electric heating auxiliary module 109 and / or control the gas discharged from the exhaust pipe 103 to be transmitted from the evaporator 105 to the condenser 110, and then transmitted to the compressor 102 through the air intake pipe of the compressor 102, so as to defrost the evaporator 105;

[0088] Among them, when the heat storage temperature of the waste heat recovery module 101 is lower than the first preset temperature, it means that the heat stored in the waste heat recovery module 101 cannot complete the defrosting work of the evaporator 105. After the waste heat recovery module 101 and the evaporator 105 are connected for a preset time, when the temperature detected by the second temperature detection module 108 is lower than the second preset temperature, it also means that the heat stored in the waste heat recovery module 101 cannot complete the defrosting work of the evaporator 105. At this time, the control module 106 can start the electric heating auxiliary module 109 and / or control the gas discharged from the exhaust pipe 103 to be transmitted from the evaporator 105 to the condenser 110, and then transmitted to the compressor 102 through the air intake pipe of the compressor 102, so as to defrost the evaporator 105.

[0089] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0090] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A waste heat recovery auxiliary defrosting system, characterized in that: It includes a waste heat recovery module and at least one heat pump unit, wherein the heat pump unit includes a compressor, an exhaust pipe, a switch module and an evaporator; The exhaust pipe is connected to the exhaust port of the compressor, the waste heat recovery module is placed at the exhaust pipe and / or the exhaust port of the compressor, and the waste heat recovery module is used to absorb and store the heat of the exhaust gas of the compressor; The switch module is connected to the waste heat recovery module and the evaporator respectively, and is configured to transfer the heat stored in the waste heat recovery module to the evaporator when the waste heat recovery module and the evaporator are connected, so as to defrost the evaporator.

2. The system according to claim 1, characterized in that The waste heat recovery module includes a heat pipe unit and a phase change heat storage unit; The heat pipe unit is placed on the outer wall of the exhaust pipe of the compressor, and the heat pipe unit is used to absorb the heat of the exhaust gas of the compressor; The phase-change heat storage unit is respectively connected to the heat pipe unit and the switch module, and the phase-change heat storage unit is used to store the heat of the exhaust gas of the compressor.

3. The system according to claim 2, characterized in that It also includes a control module, a first temperature detection module and a second temperature detection module, wherein the control module is connected to the first temperature detection module, the second temperature detection module and the switch module respectively, and the first temperature detection module is used to detect the heat storage temperature of the phase change heat storage unit; The second temperature detection module is used to detect the surface temperature of the evaporator; The control module is used to control the switch module to transfer the heat stored in the waste heat recovery module to the evaporator to defrost the evaporator when determining that the evaporator needs to be defrosted according to the temperatures detected by the first temperature detection module and the second temperature detection module.

4. The system according to claim 3, characterized in that The heat pump unit also includes an electric heating auxiliary module, which is connected to the control module. The control module is also used to control the start-up of the electric heating auxiliary module as a supplement to defrost the evaporator when the temperature detected by the first temperature detection module is lower than a first preset temperature and / or when the temperature detected by the second temperature detection module is lower than a second preset temperature after the waste heat recovery module and the evaporator are connected for a preset time.

5. The system according to claim 3, characterized in that The switch module includes a three-way solenoid valve; The three-way solenoid valve has a first port, a second port and a third port, the first port is connected to the outlet of the phase change heat storage unit through a pipeline, the second port is connected to the condenser, and the third port is connected to the evaporator through a pipeline; The control module is used to control the first port and the third port of the three-way solenoid valve to be connected when it is detected that the evaporator needs to be defrosted, so as to transfer the heat stored in the waste heat recovery module to the evaporator; The control module is also used to control the first port to be connected to the second port when the temperature detected by the second temperature detection module is greater than a second preset temperature, so as to transfer the heat stored in the waste heat recovery module to the condenser.

6. The system according to claim 3, characterized in that The heat pump unit further comprises a condenser, and the condenser is connected to the exhaust pipe; The control module is also used to control the gas discharged from the exhaust pipe to be transmitted from the evaporator to the condenser and then to the compressor through the air intake pipe of the compressor when the temperature detected by the first temperature detection module is lower than a first preset temperature and / or when the temperature detected by the second temperature detection module is lower than a second preset temperature after the waste heat recovery module and the evaporator are connected for a preset time.

7. The system according to claim 6, characterized in that The heat pump unit further includes a four-way valve, the four-way valve including a fourth port, a fifth port, a sixth port and a seventh port, the fourth port being connected to the exhaust pipe, the fifth port being connected to the evaporator, the sixth port being connected to the compressor through a pipeline, and the seventh port being connected to the condenser through a pipeline; The control module is also used to control the fourth and fifth ports of the four-way valve to be connected, and after the gas discharged from the exhaust pipe is transferred from the evaporator to the condenser, control the sixth and seventh ports of the four-way valve to be connected, and transfer the gas to the compressor through the air intake pipe of the compressor, when the temperature detected by the first temperature detection module is lower than a first preset temperature, and / or when the temperature detected by the second temperature detection module is lower than a second preset temperature after the waste heat recovery module and the evaporator are connected for a preset time.

8. The system according to claim 3, characterized in that It comprises at least two heat pump units, the waste heat recovery module comprises at least two heat pipe units, and the heat pipe units are arranged on the outer wall of the exhaust pipe of the compressor in a one-to-one correspondence; The control module is used to determine the heat pump unit with the lowest evaporator temperature among at least two heat pump units according to the temperatures detected by each of the second temperature detection modules, and control the switch module in the heat pump unit with the lowest evaporator temperature to preferentially transfer the stored heat to the evaporator. After the heat pump unit with the lowest evaporator temperature is defrosted preferentially, the evaporators of other heat pump units are controlled to be defrosted.

9. A waste heat recovery assisted defrosting method, characterized in that: The waste heat recovery auxiliary defrosting system according to any one of claims 1 to 8 comprises: When the evaporator needs to be defrosted, the switch module is controlled to connect the waste heat recovery module and the evaporator, and the heat stored in the waste heat recovery module is transferred to the evaporator to defrost the evaporator.

10. The method according to claim 9, characterized in that When the evaporator needs to be defrosted, the switch module is controlled to connect the waste heat recovery module with the evaporator, and the heat stored in the waste heat recovery module is transmitted to the evaporator to defrost the evaporator, including: When it is determined that the evaporator needs to be defrosted according to the heat storage temperature of the waste heat recovery module detected by the first temperature detection module and the surface temperature of the evaporator detected by the second temperature detection module, the switch module is controlled to transfer the heat stored in the waste heat recovery module to the evaporator to defrost the evaporator; When the temperature detected by the first temperature detection module is lower than a first preset temperature, and / or when the temperature detected by the second temperature detection module is lower than a second preset temperature after the waste heat recovery module and the evaporator are connected for a preset time, the electric heating auxiliary module is controlled to be started and / or the gas discharged from the exhaust pipe is controlled to be transmitted from the evaporator to the condenser and then transmitted to the compressor through the air intake pipe of the compressor to defrost the evaporator.

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