Air source heat pump with energy-saving defrosting by relieving frost

Abstract

This invention relates to an air source heat pump that alleviates frost buildup and saves energy during defrosting. It includes a compressor, oil separator, four-way valve, condenser, regenerator, outdoor evaporator, liquid receiver, gas-liquid separator, auxiliary evaporator, filter, electronic expansion valve, three-way valve, three-way pipe, fan, and control unit. When the control unit detects that the outdoor evaporator is frosted and meets defrosting conditions, the heat pump defrosting begins. Under the control of the control unit, ports A and G of the three-way valve are closed, stopping the supply of low-temperature, low-pressure refrigerant to the outdoor evaporator. Ports A and B of the three-way valve are opened, allowing the low-temperature, low-pressure refrigerant to enter the auxiliary evaporator. In the auxiliary evaporator, the refrigerant absorbs stored heat and becomes high-temperature, low-pressure refrigerant before entering the outdoor evaporator through the three-way pipe. This air source heat pump has an ingenious structure; by incorporating an auxiliary evaporator, it introduces an external heat source, effectively defrosting with low energy consumption and continuous heating, ensuring indoor comfort.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air source heat pump, in particular to an air source heat pump for relieving frost and energy-saving defrosting. BACKGROUND

[0002] Air source heat pump is an energy-saving device that uses high-level energy to transfer heat from low-level heat source air to high-level heat source. It is a form of heat pump. As the name implies, heat pump is just like a pump that can convert low-level heat energy (such as heat contained in air, soil, and water) that cannot be directly utilized into high-level heat energy that can be utilized, thereby achieving the purpose of saving part of high-level energy (such as coal, gas, oil, and electricity). Its application prospect and market value are relatively extensive.

[0003] The working principle of air source heat pump is based on thermodynamics, which uses key components such as compressors, evaporators, condensers, and expansion valves to achieve heat transfer. Specifically, it absorbs heat from the air and transfers it to the refrigerant, making it evaporate into a low-temperature and low-pressure gas. Then, the compressor compresses the gas, increasing its temperature and pressure. The high-temperature and high-pressure gas passes through the condenser, releasing heat to water or air, thereby heating the indoor environment. Finally, the refrigerant passes through the expansion valve again to reduce the pressure and returns to the evaporator to absorb heat from the air again, working in a cycle.

[0004] Compared with traditional heating equipment, air source heat pump has many advantages. First, it can obtain free heat energy from the environment, so it has low energy consumption and significant energy-saving effect. Second, it can realize both heating and cooling, which can heat indoor space and also can cool. In addition, air source heat pump is also environmentally friendly because it does not produce direct emissions and does not burn fuel, reducing air pollution and greenhouse gas emissions.

[0005] During the operation of the air source heat pump, heat is absorbed from the air by the evaporator to heat. However, when the outdoor temperature is low, the evaporator surface may be frosted or iced. The system evaporator surface frosting needs to meet two conditions at the same time: 1) the heat exchanger surface temperature is lower than 0℃; 2) the heat exchanger surface temperature is lower than the dew point temperature of the ambient air. The evaporator surface temperature depends on the refrigerant evaporation temperature under the influence of the ambient temperature, and the dew point temperature of the air is affected by the relative humidity, so the air temperature and humidity become the main basis for judging whether the evaporator surface of the heat pump system is frosted or not. When the frosting conditions are met, the frosting process will go through: condensation water droplets, ice layer, frost crystals, frost branches, and frost layer. With the operation of the heat pump system, the thickness of the frost layer also increases, and with the thickening of the frost layer, the evaporation temperature decreases, the heating capacity decreases, the fan performance decays, and the current increases, etc., so that the air source heat pump unit cannot work normally. In order to ensure the winter operation efficiency of the air source heat pump system, especially the comfort and stability of room heating, appropriate methods need to be used to inhibit the frosting of the evaporator surface of the heat pump or to carry out periodic defrosting.

[0006] The existing common defrosting methods are: 1) reverse cycle defrosting method; 2) hot gas bypass defrosting method. The reverse cycle defrosting method of the air source heat pump unit is the refrigeration cycle defrosting. During the defrosting process, not only the heat is not obtained in the room, but also the cold energy stored in the heat exchanger must be eliminated first in the next heating cycle, which reduces the heating capacity. The comfort of the room is poor when using the reverse cycle defrosting method to defrost, the defrosting time is long, the system operation reliability is poor, and the user's use experience is affected. The hot gas bypass defrosting method can overcome some of the shortcomings of the reverse cycle defrosting method: because during the hot gas bypass defrosting, part of the exhaust gas is still introduced into the indoor unit, the temperature of the indoor heat exchanger remains at a high level, and heat can be dissipated to the room through natural convection. Sometimes the indoor fan can be turned on during defrosting to supply heat to the room at the same time, which greatly contributes to the indoor comfort. In addition, since the four-way valve does not reverse during defrosting and the compressor does not stop, the indoor heat exchanger maintains a high temperature during defrosting, and the indoor heat can be immediately supplied after defrosting. However, this defrosting method still has the following problems: ① long defrosting time; ② high load operation of the compressor during defrosting; ③ reliability of the compressor operation, etc., resulting in high defrosting energy consumption and increasing the user's use cost, affecting the user's use experience. SUMMARY

[0007] In order to overcome the defects in the prior art, the application aims to provide an air source heat pump with defrosting and energy-saving melting, which has a clever structure, introduces an external heat source by setting an auxiliary evaporator, stores heat energy in the auxiliary evaporator, heats refrigerant during defrosting, heats the outdoor evaporator with frost through a three-way valve and a three-way pipe, and plays a role in defrosting. Compared with the conventional defrosting and melting method, the air source heat pump has less defrosting energy consumption, can continuously supply heat during defrosting, ensures the comfort of the indoor, enhances the use experience of the user, and is beneficial to the promotion and application of the air source heat pump in the market.

[0008] In order to achieve the above application purpose, the application adopts the following technical scheme: an air source heat pump with defrosting and energy-saving melting, comprising a compressor, an oil separator, a four-way valve, a condenser, a regenerator, an outdoor evaporator, a liquid tank, a gas-liquid separator, an auxiliary evaporator, a filter, an electronic expansion valve, a three-way valve, a three-way pipe, a fan and a control part; when the heat pump is running, the refrigerant passes through the outdoor evaporator, the four-way valve, the gas-liquid separator, the compressor, the oil separator in turn, passes through the four-way valve again, and enters the condenser, the regenerator and the liquid tank in turn; the refrigerant in the liquid tank is filtered by the filter, throttled and depressurized in the electronic expansion valve, and then enters the outdoor evaporator through the three-way pipe; the outdoor evaporator is connected with the fan to form a heating cycle; when the control part detects that the outdoor evaporator is frosted to reach the defrosting condition, the heat pump defrosting starts to work; under the control of the control part, the A port and the G port of the three-way valve are closed to stop supplying low-temperature and low-pressure refrigerant to the outdoor evaporator; the A port and the B port of the three-way valve are opened to send low-temperature and low-pressure refrigerant into the auxiliary evaporator; after absorbing and storing heat in the auxiliary evaporator, the low-temperature and low-pressure refrigerant becomes high-temperature and low-pressure refrigerant, and then enters the outdoor evaporator through the three-way pipe.

[0009] As a preferred scheme of the application, during the heat pump defrosting process, the high-temperature and low-pressure refrigerant becomes low-temperature and low-pressure gaseous refrigerant after entering the outdoor evaporator through the three-way pipe, and then enters the gas-liquid separator through the four-way valve.

[0010] As a preferred scheme of the application, the outdoor evaporator is provided with a temperature sensor, and the temperature sensor is signal-connected with the control part.

[0011] As a preferred scheme of the application, the outdoor evaporator is connected with the fan through an air duct or an air pipe.

[0012] As a preferred scheme of the application, the heat energy of the auxiliary evaporator is any one or a combination of waste heat in air and electric energy.

[0013] As a preferred scheme of the present application, the driving energy source of the compressor is electric energy.

[0014] As a preferred scheme of the present application, the fan is installed at the bottom of the outdoor evaporator.

[0015] As a preferred scheme of the present application, the fan is installed at the bottom of the outdoor evaporator.

[0016] As a preferred scheme of the present application, the fan is installed at the bottom of the outdoor evaporator.

[0017] As a preferred scheme of the present application, the fan is installed at the bottom of the outdoor evaporator.

[0018] Compared with the prior art, the present application has the beneficial effects that: the air source heat pump for relieving frost and energy-saving defrosting is ingenious, when the control part detects that the outdoor evaporator frosting reaches the defrosting condition, under the control of the control part, the A port and the G port of the three-way valve are closed to stop supplying low-temperature and low-pressure refrigerant to the outdoor evaporator, the A port and the B port of the three-way valve are opened to send the low-temperature and low-pressure refrigerant into the auxiliary evaporator, after absorbing the stored heat in the auxiliary evaporator, the low-temperature and low-pressure refrigerant becomes high-temperature and low-pressure refrigerant, enters the outdoor evaporator through the three-way pipe, provides heat to the surface of the outdoor evaporator, and melts the frost layer on the surface of the outdoor evaporator to become low-temperature and low-pressure gaseous refrigerant, which enters the gas-liquid separator after the four-way valve. The compressor is driven by electric energy, compresses the low-temperature and low-pressure gaseous refrigerant from the gas-liquid separator, and discharges high-temperature and high-pressure gaseous refrigerant to the oil separator, after separating the lubricating oil, the high-temperature and high-pressure gaseous refrigerant enters the condenser through the four-way valve, and after the high-temperature and high-pressure gaseous refrigerant releases condensation heat to the hot water in the condenser, it condenses into high-pressure liquid refrigerant, and circulates in turn. After the defrosting is completed, the three-way valve closes the AB channel and opens the AG channel under the control of the control part, and the outdoor evaporator is communicated, during the whole defrosting process, the four-way valve is not reversed, the compressor continues to operate normally, the heat pump continues to provide heat to the heating user, saves energy consumption, ensures the heating of the indoor, ensures the comfort of the user during use, enhances the use experience of the user, and is beneficial to the promotion and application of the above-mentioned heat pump in the market. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structure schematic view of an air source heat pump for relieving frost and energy-saving defrosting in the embodiment.

[0020] Reference numerals: 1, compressor; 2, oil separator; 3, four-way valve; 4, condenser; 5, heat exchanger; 6, outdoor evaporator; 7, liquid receiver; 8, gas-liquid separator; 9, auxiliary evaporator; 10, filter; 11, electronic expansion valve; 12, three-way valve; 13, three-way pipe; 14, fan; 15, muffler; 16, guide vane; 17, rack; 18, control unit. DETAILED DESCRIPTION

[0021] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described below in detail through specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of well-known structures and techniques is omitted to avoid unnecessary confusion of the concept of the present application.

[0022] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0023] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0024] Embodiment: As Figure 1As shown, an air source heat pump for alleviating frosting energy-saving defrosting mainly comprises a control unit 18, a heating circulation system and a heat pump defrosting system. The heating circulation system mainly comprises a compressor 1, an oil separator 2, a four-way valve 3, a condenser 4, a heat accumulator 5, an outdoor evaporator 6, a liquid tank 7, a gas-liquid separator 8, a filter 10, an electronic expansion valve 11, a three-way valve 12, a three-way pipe 13, and a fan 14. When the heat pump is in heating operation, the refrigerant passes through the outdoor evaporator 6 and absorbs heat from the outdoor air, becoming low-temperature and low-pressure steam. After passing through the four-way valve 3, the refrigerant enters the gas-liquid separator 8. The compressor 1 is driven by electric energy, compresses the low-temperature and low-pressure gaseous refrigerant from the gas-liquid separator 8, and discharges high-temperature and high-pressure gaseous refrigerant to the oil separator 2. After the oil separator 2 separates out the lubricating oil, the high-temperature and high-pressure gaseous refrigerant enters the condenser 4 through the four-way valve 3. In the condenser 4, the high-temperature and high-pressure gaseous refrigerant releases condensation heat to the hot water and condenses into high-pressure liquid refrigerant. The high-pressure liquid refrigerant enters the heat accumulator 5, becomes supercooled high-pressure refrigerant, and enters the liquid tank 7. After filtration by the filter 10, the refrigerant is throttled and depressurized in the electronic expansion valve 11, becoming low-temperature and low-pressure refrigerant liquid. After passing through the three-way valve 12, the refrigerant enters the outdoor evaporator 6 through the three-way pipe 13, absorbs heat from the outdoor air in the outdoor evaporator 6, and evaporates into low-temperature and low-pressure gaseous refrigerant. This cycle is repeated to form a heating circulation. The hot water that has absorbed condensation heat from the condenser 4 is pumped into the heating user by the water pump, and the system circulates to continuously provide heat to the heating user.

[0025] The main function of the heat pump is: 1) to raise the heat from a lower temperature to a higher temperature, which consumes useful energy and absorbs heat from the low-temperature heat source; 2) to complete the heat transfer process, in which the compressor 1 plays a role in transferring heat from the low-temperature heat source to the high-temperature heat source.

[0026] During operation of the air source heat pump, heat is absorbed from the air by the outdoor evaporator 6 to heat up. However, when the outdoor temperature is low, frost or ice may form on the surface of the outdoor evaporator 6. This will cause the heat exchange efficiency of the outdoor evaporator 6 to decrease, thereby affecting the performance and heating effect of the heat pump. Therefore, in order to ensure the normal operation of the heat pump, defrosting operation must be performed.

[0027] The heat pump defrosting system in this embodiment is used in cooperation with the heating circulation system. In addition to the shared components, the heat pump defrosting system also has an auxiliary evaporator 9. When the control unit 18 detects that the outdoor evaporator 6 has reached the defrosting condition, the heat pump defrosting system starts to work. Specifically, the control unit 18 can use various methods to detect the frosting of the outdoor evaporator 6. Some common detection methods are as follows: Temperature sensor: The control unit 18 installs one or more temperature sensors on the outdoor evaporator 6. These temperature sensors can measure the temperature of the surface of the outdoor evaporator 6. When the temperature is below the frosting point, frosting may occur. The control unit 18 can detect the frosting condition by monitoring the change of temperature. Humidity sensor: The humidity sensor can be used to detect the air humidity around the outdoor evaporator 6. When the air humidity is higher than a certain threshold, the possibility of frosting increases. The control unit 18 can use the humidity sensor to monitor the change of humidity and determine whether frosting occurs according to the set conditions. Differential pressure sensor: Frosting will cause the airflow on the surface of the outdoor evaporator 6 to be blocked, which will affect the circulation of the refrigerant and the differential pressure. By installing a differential pressure sensor, the control unit 18 can monitor the inlet and outlet pressure difference of the outdoor evaporator 6. When the pressure difference exceeds the preset threshold, it may indicate that the evaporator is frosting. Time control: The control unit 18 can estimate the frosting condition through time control. According to factors such as environmental conditions and running time, the control unit 18 can determine the possibility of frosting according to empirical rules or preset algorithms. For example, if the control unit 18 runs for a period of time under low temperature conditions, it can assume that frosting may occur. The above methods can be used alone or in combination, depending on the specific control system and application requirements. By monitoring parameters such as the temperature, humidity, pressure difference or running time of the outdoor evaporator 6, the control unit 18 can discover the frosting condition in time and take appropriate measures, such as adjusting the refrigerant flow or using defrosting strategies, to prevent or solve the frosting problem of the outdoor evaporator 6.

[0028] When the defrosting condition is met, the defrosting process will go through: condensation of water droplets, ice layer, frost crystals, frost branches, and frost layer. As the heat pump system operates, the frost layer thickness also increases. As the frost layer thickens, the evaporation temperature will decrease, the heating capacity will decrease, the fan performance will decrease, and the current will increase. When the control unit 18 detects that the outdoor evaporator 6 has reached the defrosting condition, under the control of the control unit 18, the A port and the G port of the three-way valve 12 are closed, and the low-temperature and low-pressure refrigerant is stopped from being supplied to the outdoor evaporator 6. The A port and the B port of the three-way valve 12 are opened to send the low-temperature and low-pressure refrigerant into the auxiliary evaporator 9. After absorbing the stored heat in the auxiliary evaporator 9, the low-temperature and low-pressure refrigerant becomes high-temperature and low-pressure refrigerant, which enters the outdoor evaporator 6 through the three-way pipe 13, provides heat to the surface of the outdoor evaporator 6, and melts the frost layer on the surface of the outdoor evaporator 6, and changes into low-temperature and low-pressure gaseous refrigerant, which enters the gas-liquid separator 8 after passing through the four-way valve 3. In this process, the compressor 1 is driven by electricity, compresses the low-temperature and low-pressure gaseous refrigerant from the gas-liquid separator 8, and discharges high-temperature and high-pressure gaseous refrigerant to the oil separator 2. After the oil separator 2 separates the lubricating oil, the high-temperature and high-pressure gaseous refrigerant enters the condenser 4 through the four-way valve 3. After the high-temperature and high-pressure gaseous refrigerant releases condensation heat to the hot water in the condenser 4, it condenses into high-pressure liquid refrigerant, and the cycle continues. After the defrosting is completed, the three-way valve 12 closes the AB channel and opens the AG channel under the control of the control unit 18. During the entire defrosting process, the four-way valve 3 does not reverse, the compressor 1 continues to operate normally, and the heat pump continues to provide heat to the heating user, ensuring the operation effect of the heat pump and enhancing the user experience. The way to provide heat to the auxiliary evaporator 8 depends on the site conditions of the heat pump operation, which can use electric heating, boiler hot water, waste heat, etc. The best choice is waste heat utilization to save energy and reduce user costs.

[0029] The outdoor evaporator 6 is connected to the fan 14 through an air duct or air pipe. In an air source heat pump, the fan 14 plays an important role. It mainly has the following functions: supplying air flow: the fan 14 of the air source heat pump is responsible for sucking air from the outdoor, and then conducting heat exchange through the outdoor evaporator 6 (heat exchanger). The fan 14 generates air flow, so that the air can flow smoothly, and ensures the efficient operation of the outdoor evaporator 6. Promote heat transfer: the operation of the fan 14 can help to strengthen the heat transfer. When the air passes through the outdoor evaporator 6, the action of the fan 14 can increase the contact area between the air and the outdoor evaporator 6, speed up the speed of heat transfer, and improve the heat exchange efficiency. Maintain system balance: the air source heat pump needs to maintain the balance of heat between the indoor and outdoor. The fan 14 can help to adjust the flow speed and direction of the air, so that the heat is evenly distributed among the different outdoor evaporators 6, and the system runs in balance. In general, the fan 14 in the air source heat pump plays the role of promoting air flow, enhancing heat transfer, maintaining system balance and providing indoor air circulation. These functions help to improve the efficiency and performance of the heat pump system, and ensure that the system can effectively heat or cool.

[0030] The driving energy source of the compressor 1 is electrical energy. In addition to electrical energy, the driving power source of the compressor 1 can also be other forms of energy, depending on the design and application scenario of the heat pump system. Here are some possible driving power source options: Gas: Some heat pump systems can use gas as the driving power source of the compressor 1. Gas-driven compressors 1 can use natural gas, liquefied petroleum gas (LPG) and other fuels as fuel, and the heat energy generated during combustion drives the compressor 1 to work. Steam: In some industrial applications, heat pump systems can use steam as the driving power source of the compressor 1. Steam-driven compressors 1 use the pressure and kinetic energy of steam to drive the compressor 1 to work. Diesel or fuel oil: In some special application scenarios, heat pump systems can use diesel or fuel oil as the driving power source of the compressor 1. This type of system is usually used in places away from the power grid or in environments where electricity cannot be supplied. It should be noted that electrical energy is still the most common and widely used driving power source for compressors because electricity supply is generally reliable and convenient. Other non-electric driving heat pump systems are usually used in specific application environments and may face some technical and economic challenges. Therefore, in most cases, the driving power source of the compressor 1 is still electrical energy. The use of electrical energy as the driving power source of the compressor 1 has the following main advantages: Widely available: Electrical energy is a widely available form of energy, and electricity is available almost everywhere in the world. Compared with other energy forms such as gas or fuel oil, electrical energy is more easily accessible and distributed. Environmentally friendly: Compared with combustion-based energy, the use of electrical energy does not produce exhaust gas, waste or emissions. This makes it more environmentally friendly to use electrical energy to drive the compressor, helping to reduce air pollution and greenhouse gas emissions. High efficiency: Electrically driven compressors generally have higher energy conversion efficiency. Modern electric compressor design and control technology can provide higher efficiency and performance, making heat pump systems more energy-efficient and efficient. Adjustable: Using electrical energy as the driving power source allows for precise control and adjustment. Through electronic control systems, the speed and power of the compressor can be adjusted according to demand to better adapt to different working conditions and loads. Safety: Compared with other energy forms such as gas or fuel oil, the use of electrical energy is safer and more reliable. The power system is subject to strict safety standards and regulations, and the use and maintenance of electric equipment is relatively simple and safe. In summary, using electrical energy as the driving power source of the compressor 1 has the advantages of wide availability, environmental friendliness, high efficiency, adjustability and safety. These advantages make electrical energy the most common and recommended driving energy source for the compressor 1.

[0031] In this embodiment, by installing the above-mentioned fan 14 at the bottom of the above-mentioned outdoor evaporator 6, when the air source heat pump is running, the air direction is consistent with the direction of water droplet gravity, and the condensed water on the surface of the outdoor evaporator 6 is easily carried away, delaying frost formation. It can also make the air flow evenly on the entire surface of the outdoor evaporator 6, maximizing heat exchange efficiency. The fan 14 sucks cold air from the bottom and raises them along the outdoor evaporator 6 to increase the contact area of the heat exchange surface, thereby improving the heat transfer effect. Installing the fan 14 at the bottom of the outdoor evaporator 6 can provide additional protection from exposure to harsh environmental conditions. The outdoor evaporator 6 is usually exposed to external air and may be affected by factors such as wind, rain, dust, etc. Placing the fan 14 at the bottom can reduce the direct impact of these external factors on the fan, prolong the service life of the fan 14, and reduce the user's use cost. Installing the fan 14 at the bottom of the outdoor evaporator 6 can reduce the overall height of the system, thereby improving space utilization efficiency. Especially in the installation environment of limited space, this layout can better meet the space constraints. Installing the fan 14 at the bottom of the outdoor evaporator 6 can also reduce noise propagation. The fan 14 blows air upwards, reducing direct contact with the surrounding environment during air flow, thereby reducing noise propagation, reducing noise interference for users, and enhancing user experience.

[0032] In order to provide a stable support platform for the fan 14, the above-mentioned fan 14 is installed on the rack 17, which can be a frame structure, the main purpose is to realize the supporting effect, and the specific structure is not limited here. Installing the fan 14 on the rack 17 can improve the air circulation effect. The rack 17 can improve the position of the fan 14, making it easier for air to be sucked in and discharged, which helps to increase air flow speed and circulation efficiency, improving heat exchange efficiency.

[0033] In order to reduce the impact of noise on surrounding personnel or residential areas, a soundproof device 15 is provided around the above-mentioned fan 14, and in order to avoid the soundproof device 15 from falling off, the above-mentioned soundproof device 15 is fixed on the above-mentioned rack 17 by means of fastening bolts, etc. It can reduce the impact on the fan 14 while playing a noise reduction role. The soundproof device 15 can be soundproof cotton, etc.

[0034] In order to play the role of wind flow guide and reduce resistance, the bottom of the above-mentioned fan 14 is provided with a flow guide plate 16, and the above-mentioned flow guide plate 16 is fixed on the above-mentioned rack 17 by bolts. Further, in order to better play the role of wind flow guide, the cross section of the flow guide plate 16 is arranged in the shape of a "person".

[0035] The air source heat pump of the present embodiment is ingenious, and when the control unit 18 detects that the outdoor evaporator 6 has frost that reaches the defrosting condition, under the control of the control unit 18, the A port and the G port of the three-way valve 12 are closed, and the supply of low-temperature and low-pressure refrigerant to the outdoor evaporator 6 is stopped, the A port and the B port of the three-way valve 12 are opened to send the low-temperature and low-pressure refrigerant into the auxiliary evaporator 9, and after absorbing the stored heat in the auxiliary evaporator 9, the low-temperature and low-pressure refrigerant becomes high-temperature and low-pressure refrigerant, enters the outdoor evaporator 6 through the three-way pipe 13, provides heat to the surface of the outdoor evaporator 6, and melts the frost layer on the surface of the outdoor evaporator 6 into low-temperature and low-pressure gaseous refrigerant, which enters the gas-liquid separator 8 after the four-way valve 3. The compressor 1 is driven by electric energy, compresses the low-temperature and low-pressure gaseous refrigerant from the gas-liquid separator 8, and discharges high-temperature and high-pressure gaseous refrigerant to the oil separator 2, and after separating the lubricating oil, the high-temperature and high-pressure gaseous refrigerant enters the condenser 4 through the four-way valve 3, and after the high-temperature and high-pressure gaseous refrigerant releases condensation heat to the hot water in the condenser 4, it condenses into high-pressure liquid refrigerant, and circulates in sequence. After the defrosting is completed, the three-way valve 12 closes the AB channel and opens the AG channel under the control of the control unit 18, and the four-way valve 3 does not reverse during the entire defrosting process, and the compressor 1 continues to operate normally, and the heat pump continues to provide heat to the heating user, saves energy consumption, ensures the heating of the indoor, ensures the comfort of the user during use, enhances the user experience, and is conducive to the promotion and application of the above-mentioned heat supply air source heat pump in the market.

[0036] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application; therefore, the application is not to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0037] Although the terms: 1, compressor; 2, oil separator; 3, four-way valve; 4, condenser; 5, heat accumulator; 6, outdoor evaporator; 7, liquid tank; 8, gas-liquid separator; 9, auxiliary evaporator; 10, filter; 11, electronic expansion valve; 12, three-way valve; 13, three-way pipe; 14, fan; 15, silencer; 16, guide plate; 17, rack; 18, control unit, etc. are used more frequently in the drawings, the possibility of using other terms is not excluded. The use of these terms is only for the convenience of describing and explaining the essence of the application; any interpretation of them as any kind of additional limitation is contrary to the spirit of the application.

Claims

1. An air source heat pump with defrost energy saving by mitigating frost, characterized by: It comprises a compressor (1), an oil separator (2), a four-way valve (3), a condenser (4), a regenerator (5), an outdoor evaporator (6), a liquid tank (7), a gas-liquid separator (8), an auxiliary evaporator (9), a filter (10), an electronic expansion valve (11), a three-way valve (12), a three-way pipe (13), a fan (14) and a control unit (18); when the heat pump is in heating operation, the refrigerant passes through the outdoor evaporator (6), the four-way valve (3), the gas-liquid separator (8), the compressor (1) and the oil separator (2) in turn, and passes through the four-way valve (3) again and enters the condenser (4), the regenerator (5) and the liquid tank (7) in turn; the refrigerant in the liquid tank (7) is filtered by the filter (10), throttled and depressurized in the electronic expansion valve (11), and then enters the outdoor evaporator (6) through the three-way pipe (13); the outdoor evaporator (6) is connected with the fan (14) to form a heating cycle; when the control unit (18) detects that the outdoor evaporator (6) has reached the defrosting condition, the heat pump defrosting starts to work; under the control of the control unit (18), the A port and the G port of the three-way valve (12) are closed to stop supplying low-temperature and low-pressure refrigerant to the outdoor evaporator (6); the A port and the B port of the three-way valve (12) are opened to send low-temperature and low-pressure refrigerant into the auxiliary evaporator (9); after absorbing the stored heat in the auxiliary evaporator (9), the low-temperature and low-pressure refrigerant becomes high-temperature and low-pressure refrigerant; during the heat pump defrosting process, the high-temperature and low-pressure refrigerant enters the outdoor evaporator (6) through the three-way pipe (13) and becomes low-temperature and low-pressure gaseous refrigerant, and then enters the gas-liquid separator (8) through the four-way valve (3).

2. The air source heat pump with defrost alleviation and energy saving according to claim 1, characterized in that: The outdoor evaporator (6) is provided with a temperature sensor which is signal-connected with the control unit (18).

3. The air source heat pump with defrost alleviation and energy saving according to claim 1, characterized in that: The outdoor evaporator (6) is connected with the fan (14) through an air duct or an air pipe.

4. The air source heat pump with defrost alleviating and energy saving according to claim 1, characterized in that: The auxiliary evaporator (9) uses any one of air waste heat and electric energy or a combination of both.

5. The air source heat pump with defrost alleviating and energy saving according to claim 4, characterized in that: The driving energy source of the compressor (1) is electric energy.

6. The air source heat pump with defrost alleviating and energy saving according to claim 1, characterized in that: The fan (14) is installed at the bottom of the outdoor evaporator (6).

7. The air source heat pump with defrost alleviating and energy saving according to claim 6, characterized in that: The fan (14) is installed on a rack (17).

8. The air source heat pump with defrost alleviating and energy saving according to claim 7, characterized in that: The fan (14) is provided with a sound attenuation device (15) around it, and the sound attenuation device (15) is fixed to the rack (17).

9. The air source heat pump with defrost alleviating and energy saving according to claim 8, characterized in that: The fan (14) is provided with a guide vane (16) at the bottom, and the guide vane (16) is installed on the rack (17).

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