Air source heat pump system adopting flash evaporator

Abstract

The utility model discloses an air source heat pump system adopting a flash evaporator. The air source heat pump system comprises a compressor, a four-way reversing valve, a water side heat exchanger, the flash evaporator, an electronic expansion valve, an air side heat exchanger, a gas-liquid separator, a first electromagnetic valve, a second electromagnetic valve and a throttling mechanism. During defrosting, if the low pressure is too low, the low pressure can be increased by different amplitudes by controlling the first electromagnetic valve and the second electromagnetic valve, so that the low pressure of the system is controlled to be in a safe area all the time; the compressor is effectively prevented from being abraded in the defrosting process, or the heat exchanger is effectively prevented from frost cracking caused by local icing in the heat exchanger due to too low low pressure in the defrosting process of plate exchange, sleeve and shell and tube heat exchange.

Description

Technical Field

[0001] The utility model relates to an air source heat pump system adopting a flash evaporator. Background Art

[0002] The traditional defrosting method of air source heat pump system relies on the expansion valve for adjustment, which can only meet the defrosting requirements in some cases. When the expansion valve is too small or too large, it is easy to cause the water side heat exchanger to freeze and crack, or the compressor to return liquid or increase the compression ratio and cause the compressor to be damaged. Utility Model Content

[0003] In view of the above problems, the utility model provides an air source heat pump system using a flash evaporator, which effectively solves the problems pointed out in the background technology.

[0004] The technical solution adopted by the utility model is:

[0005] An air source heat pump system using a flash evaporator comprises a compressor, a four-way reversing valve, a water-side heat exchanger, a flash evaporator, an electronic expansion valve, an air-side heat exchanger, a gas-liquid separator, a first solenoid valve, a second solenoid valve and a throttling mechanism, wherein the exhaust port of the compressor is connected to the D port of the four-way reversing valve, the C port of the four-way reversing valve is connected to the E port of the four-way reversing valve after passing through the water-side heat exchanger, the flash evaporator, the electronic expansion valve and the air-side heat exchanger in sequence, the S port of the four-way reversing valve is connected to the return air port of the compressor after passing through the gas-liquid separator, the first solenoid valve and the throttling mechanism are connected in series to form a throttling pipeline, one end of the throttling pipeline is connected to the exhaust port of the compressor, and the other end is connected to the pipeline between the water-side heat exchanger and the flash evaporator, one end of the second solenoid valve is connected to the flash evaporator, and the other end is connected to the inlet of the gas-liquid separator.

[0006] Preferably, a low pressure detector is provided on the pipeline of the compressor air return port.

[0007] During defrosting, if the low pressure is too low, the utility model can control the first solenoid valve and the second solenoid valve to increase the low pressure to different extents, thereby controlling the low pressure of the system to always be in a safe area, effectively preventing the compressor from being worn during the defrosting process or preventing plate, sleeve, and shell and tube heat exchangers from partially freezing in the heat exchanger due to too low a low pressure during defrosting, thereby causing the heat exchanger to freeze and crack.

[0008] The beneficial effects of the utility model are as follows:

[0009] 1. Can effectively prevent the system pressure from decreasing during the defrosting process;

[0010] 2. Solve the problem of compressor damage caused by large compression ratio due to low pressure reduction;

[0011] 3. Increase the inlet and outlet pressure of the water-side heat exchanger to prevent the heat exchanger from freezing and cracking due to local freezing;

[0012] 4. If the system water flow rate decreases, it can prevent the system heat exchanger from freezing;

[0013] 5. While solving the defrosting problem, the gaseous refrigerant in the throttled gas-liquid mixed refrigerant can be separated in advance, which can increase the cooling capacity of the system during refrigeration. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the system schematic diagram of the air source heat pump;

[0015] Figure 2 This is the control principle diagram of the utility model during defrosting. DETAILED DESCRIPTION

[0016] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0017] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0018] In addition, in the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0019] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "plurality" means two or more, unless otherwise clearly defined.

[0020] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0022] The present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0023] like Figure 1 As shown, an air source heat pump system using a flash evaporator includes a compressor 1, a four-way reversing valve 2, a water-side heat exchanger 3, a flash evaporator 4, an electronic expansion valve 5, an air-side heat exchanger 6, a gas-liquid separator 7, a first solenoid valve 8, a second solenoid valve 9 and a throttling mechanism 10. The throttling mechanism 10 can use an electronic expansion valve. The exhaust port of the compressor 1 is connected to the D port of the four-way reversing valve 2. The C port of the four-way reversing valve 2 passes through the water-side heat exchanger 3, the flash evaporator 4, the electronic expansion valve in sequence. 5. The air-side heat exchanger 6 is connected to the E port of the four-way reversing valve 2, and the S port of the four-way reversing valve 2 is connected to the return air port of the compressor 1 after passing through the gas-liquid separator 7. The first solenoid valve 8 and the throttling mechanism 10 are connected in series to form a throttling pipeline, one end of the throttling pipeline is connected to the exhaust port of the compressor 1, and the other end is connected to the pipeline between the water-side heat exchanger 3 and the flash evaporator 4. One end of the second solenoid valve 9 is connected to the flash evaporator 4, and the other end is connected to the inlet of the gas-liquid separator 7.

[0024] A low pressure detector 11 is provided on the pipeline of the air return port of the compressor 1 .

[0025] For the air source heat pump system, the utility model also provides a defrosting control method for an air source heat pump, the control principle of which is as follows: Figure 2As shown, when the air source heat pump enters defrosting, the following control is performed according to the system low pressure Lp detected by the low pressure detector:

[0026] 1) When Lp>A, conventional defrosting is performed, i.e., action 1. This is the first refrigerant flow direction during defrosting, i.e., the four-way reversing valve is controlled to reverse for defrosting. The high-temperature and high-pressure gaseous refrigerant discharged from the compressor passes through the four-way reversing valve and enters the air-side heat exchanger. The fan generates forced convection heat exchange to condense the high-temperature and high-pressure gaseous refrigerant into medium-temperature and high-pressure liquid refrigerant. Since the refrigerant temperature is higher than the outdoor air temperature and the frost layer temperature on the heat exchanger surface, the frost layer on the heat exchanger surface can be melted to achieve the purpose of defrosting. After throttling and reducing the pressure by the electronic expansion valve, a low-temperature and low-pressure gas-liquid mixed refrigerant is formed, which passes through the flash evaporator and enters the water-side heat exchanger. In the water-side heat exchanger, the refrigerant and water are heat exchanged to expand and evaporate. After forming a low-temperature and low-pressure gaseous refrigerant, it passes through the four-way valve and enters the gas-liquid separator for gas-liquid separation, and finally returns to the suction port of the compressor to form a cycle.

[0027] 2) When B≤Lp≤A, the electronic expansion valve throttles and then flows through the water side heat exchanger and the four-way reversing valve before entering the compressor. At this time, a small pressure loss is generated due to passing through various components, which reduces the low pressure. While performing conventional defrosting, the second solenoid valve is opened and the first solenoid valve is closed, that is, action 2. The gaseous refrigerant separated by the flash evaporator is directly sent to the gas-liquid separator and returned to the suction port of the compressor, which slightly increases the low pressure at the suction port of the compressor. This is the second refrigerant flow direction during defrosting. The specific refrigerant flow direction is as follows: the flash gas generated after the electronic expansion valve throttles is directly sent to the gas-liquid separator, mixed with the refrigerant after flowing through the water side heat exchanger and the four-way reversing valve, and then returned to the suction port of the compressor. Because the flash gas separated by the flash evaporator has not passed through the water side heat exchanger and the pressure reduction of the four-way reversing valve, the low pressure at the suction port of the compressor can be increased;

[0028] 3) When Lp<B, the pressure loss of the refrigerant passing through various components is large, and the low pressure needs to be greatly increased. In order to prevent the water side heat exchanger from freezing and cracking or the compressor from wearing due to low low pressure, the first solenoid valve is opened and the second solenoid valve is closed while performing routine defrosting, that is, action 3, to mix part of the high temperature and high pressure gaseous refrigerant discharged from the compressor exhaust port with the low temperature and low pressure gas-liquid mixed refrigerant flowing out of the flash evaporator, increase the inlet pressure and outlet pressure of the water side heat exchanger, and greatly increase the low pressure of the compressor suction port. This is the third refrigerant flow direction during defrosting. The high temperature and high pressure gaseous refrigerant discharged from the compressor passes through the first solenoid valve and the throttling mechanism after opening to adjust the refrigerant flow, so that the high temperature and high pressure gaseous refrigerant is mixed with the low temperature and low pressure gas-liquid mixed refrigerant, increase the inlet pressure and outlet pressure of the water side heat exchanger, and increase the low pressure of the compressor suction port.

[0029] Finally, it should be noted that the above examples are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art from the present invention should be considered as the protection scope of the present invention.

Claims

1. An air source heat pump system using a flash evaporator, It is characterized in that The invention comprises a compressor (1), a four-way reversing valve (2), a water-side heat exchanger (3), a flash evaporator (4), an electronic expansion valve (5), an air-side heat exchanger (6), a gas-liquid separator (7), a first solenoid valve (8), a second solenoid valve (9) and a throttling mechanism (10), wherein the exhaust port of the compressor (1) is connected to the D port of the four-way reversing valve (2), and the C port of the four-way reversing valve (2) passes through the water-side heat exchanger (3), the flash evaporator (4), the electronic expansion valve (5), the air-side heat exchanger (6) and the four-way The first electromagnetic valve (8) and the throttling mechanism (10) are connected in series to form a throttling pipeline, one end of the throttling pipeline is connected to the exhaust port of the compressor (1), and the other end is connected to the pipeline between the water side heat exchanger (3) and the flash evaporator (4); one end of the second electromagnetic valve (9) is connected to the flash evaporator (4), and the other end is connected to the inlet of the gas-liquid separator (7).

2. An air source heat pump system using a flash evaporator according to claim 1, It is characterized in that A low pressure detector (11) is provided on the pipeline of the air return port of the compressor (1).

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