Air conditioner unit

Abstract

The present invention discloses an air-conditioning unit, comprising: a first-stage compressor, a first-stage condenser and a heat exchanger. One heat exchange branch coming out of the heat exchanger is sequentially connected to a first-stage evaporator and an ejector, and another heat exchange branch is sequentially connected to a second-stage compressor, a second-stage condenser and the ejector. A switchable first branch is connected between the outlet sides of the first-stage evaporator and the second-stage evaporator, and a second switching valve is provided on the pipeline between the second-stage condenser and the ejector. By improving the pipeline structure of the unit, the present invention can realize the switching between large temperature difference heating and conventional heating, and improve the heating demand in the whole heating season. In the large temperature difference mode, high-temperature hot water can be produced for heating water supply at ultra-low ambient temperatures; while at the beginning stage of the heating season, the ambient temperature is relatively high, and medium and low-temperature hot water can meet the demand. At this time, the participation of components is reduced, the system pressure drop is reduced, and the system operation performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and particularly to an air conditioner unit. Background Art

[0002] Currently, under the background of energy conservation and emission reduction, air source is used to replace gas boilers for heating in the north, which greatly reduces environmental pollution. However, the conventional water supply temperature range of a normal-temperature air source heat pump unit is about 45 - 50 °C for hot water heating, and the ambient temperature limit range is generally above -15 °C. For northern heating areas, especially extremely cold areas such as the east and west, during the heating period, the ambient temperature is higher than -15 °C in some periods and lower than -15 °C, reaching -35 °C or lower in some periods. When the ambient temperature is higher than -15 °C, a traditional single-stage compression cycle can be used. When the ambient temperature is too low, the evaporation temperature will be very low, which means the condensation temperature will be very high, and the temperature difference between the condensation temperature and the evaporation temperature is large. A multi-stage compression method is required to improve the performance of the unit. However, the existing heating systems cannot switch between multi-stage compression and single-stage compression. Generally, only multi-stage compression can be used, and when the ambient temperature is not very low, the efficiency of single-stage compression is higher. Summary of the Invention

[0003] In order to solve the technical problem that the existing heating system in the above-mentioned prior art cannot switch between multi-stage compression and single-stage compression, the present invention provides an air conditioner unit.

[0004] The technical solution adopted by the present invention is as follows:

[0005] The present invention provides an air conditioner unit, including: a first-stage compressor, a first-stage condenser, and a heat exchanger connected in sequence through pipelines. The pipeline on the outlet side of the first-stage condenser is divided into two heat exchange branches to connect to the heat exchanger. One heat exchange branch coming out of the heat exchanger is sequentially connected to a first-stage evaporator and an ejector, and the other heat exchange branch is sequentially connected to a second-stage compressor, a second-stage condenser, and the ejector. The pipeline on the outlet side of the ejector is sequentially connected to a second-stage evaporator and the first-stage compressor. A breakable first branch is connected between the outlet sides of the first-stage evaporator and the second-stage evaporator, and a second switching valve is provided on the pipeline between the second-stage condenser and the ejector.

[0006] Further, a gas-liquid separator is connected to the intake pipeline of the first-stage compressor.

[0007] Preferably, the heat exchanger is a plate heat exchanger.

[0008] Further, an intermediate pipeline is connected between the water supply pipeline of the first-stage condenser and the return water pipeline of the second-stage condenser, and an intermediate switching valve is provided on the intermediate pipeline.

[0009] Further, the return water pipe of the secondary evaporator is connected in parallel with the return water pipe of the primary condenser.

[0010] Further, the outlet side of the primary condenser is divided into two heat exchange branches, namely the first heat exchange branch and the second heat exchange branch. The first heat exchange branch is connected to the heat exchanger and the primary evaporator, and the second heat exchange branch is connected to the heat exchanger and the secondary compressor. A second throttle valve is provided on a section of the second heat exchange branch near the inlet side of the heat exchanger, and a first throttle valve is provided on a section of the first heat exchange branch near the outlet side of the heat exchanger.

[0011] Further, a first switching valve is provided on the first branch. A third switching valve is provided on the connecting pipe between the primary evaporator and the ejector.

[0012] Preferably, the switching valve is a solenoid valve.

[0013] Preferably, the air-conditioning unit is an air-source heat pump unit.

[0014] Compared with the prior art, by improving the pipeline structure of the unit, the present invention can realize the switching between large temperature difference heating and conventional heating, and improve the heating demand in the whole heating season. In the large temperature difference mode, high-temperature hot water can be produced for heating water supply at ultra-low ambient temperatures; while at the beginning stage of the heating season, the ambient temperature is relatively high, and medium and low-temperature hot water can meet the demand. At this time, the participation of components is reduced, the system pressure drop is reduced, and the system operation performance is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic structural diagram of an embodiment of the present invention;

[0017] Figure 2 It is a schematic structural diagram of the large temperature difference mode in an embodiment of the present invention;

[0018] Figure 3 It is a schematic structural diagram of the conventional temperature mode in an embodiment of the present invention.

[0019] 1. Primary compressor; 2. Secondary compressor; 3. Primary condenser; 4. Secondary condenser; 5. First throttle valve; 6. Second throttle valve; 7. Plate heat exchanger; 8. Primary evaporator; 9. Secondary evaporator; 10. Ejector; 11. Gas-liquid separator; 12. First switching valve; 13. Second switching valve; 14. Intermediate switching valve; 15. Third switching valve. Detailed implementation mode

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] The principle and structure of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0022] In the northern heating areas, most of them now use air source to replace gas boilers for heating, which greatly reduces environmental pollution. However, due to the relatively low environmental temperature in winter in the north, the evaporation temperature will be very low, and the transportation pipeline in the centralized section is relatively long. The required supply water temperature is higher than that of conventional heat pump units, which means that the condensation temperature will be very high, and the temperature difference between the condensation temperature and the evaporation temperature is relatively large. Therefore, a multi-stage compressor needs to be used for multi-stage compression cycle to increase the supply water temperature. However, the existing multi-stage heating units cannot be switched into conventional temperature single-stage heating units as needed. Because when the outdoor temperature is not very low, using a single-stage heating unit can reduce the refrigerant from entering too many components and has a higher heat exchange efficiency. In contrast, the present invention proposes an air source heat pump unit. By adding some pipelines and valves, the refrigerant flow path can be adjusted, enabling users to change the heating mode according to the actual situation, thereby improving the overall use efficiency of the unit.

[0023] As Figures 1 to 3As shown in the figure, the present invention proposes an air-conditioning unit, which includes: a primary compressor 1, a secondary compressor 2, a primary evaporator 8 (air-side heat exchanger), a secondary evaporator 9, an ejector 10, a heat exchanger, a primary condenser 3, and a secondary condenser 4. Specifically, the exhaust pipeline of the primary compressor 1 is connected to the inlet side of the primary condenser 3, and the pipeline on the outlet side of the primary condenser 3 is divided into two heat exchange branches, both of which are connected to the heat exchanger. The refrigerant in the two heat exchange branches is heat-exchanged through the heat exchanger. Moreover, the outlet side of the heat exchanger is also connected to two heat exchange branches, corresponding to the two heat exchange branches at the inlet end (it should be noted that for the sake of convenient expression, it will be directly stated later that the two heat exchange branches pass through the heat exchanger. In fact, the heat exchanger has four interfaces corresponding to each other in pairs). One of the heat exchange branches is connected to the primary evaporator 8 after passing through the heat exchanger, and the primary evaporator is then connected to the inlet side of the ejector 10 through a pipeline. The outlet side of the ejector 10 is connected to the secondary evaporator 9 through a pipeline, and the pipeline on the outlet side of the secondary evaporator 9 is connected to the intake pipeline of the primary compressor 1, forming a refrigerant circulation channel. That is, the primary compressor 1, the primary condenser 3, the heat exchanger, the primary evaporator, and the ejector 10 are connected to carry out refrigerant circulation. The other heat exchange branch on the outlet side of the primary condenser 3 is connected to the intake pipeline of the secondary compressor 2 after passing through the heat exchanger. The exhaust pipeline of the secondary compressor 2 is connected to the secondary condenser 4, and the secondary condenser 4 is then connected to another inlet of the ejector 10 through a pipeline, forming a secondary refrigerant circulation channel. A switchable first branch is connected between the outlet side of the primary evaporator 8 and the outlet side of the secondary evaporator 9, that is, a first switch valve 12 is provided on the first branch, a second switch valve 13 is provided on the pipeline connecting the secondary condenser 4 and the ejector 10, and a third switch valve 15 is provided on the pipeline connecting the primary evaporator 8 and the ejector 10. When operating in the large temperature difference mode, the first switch valve 12 on the first branch 121 is closed, and the second switch valve 13 and the third switch valve 15 are opened. When it is necessary to switch to the conventional temperature mode, the first switch valve 12 on the first branch is opened, and the second switch valve 13, the third switch valve 15, and the secondary compressor 2 are closed, so that the refrigerant coming out of the primary evaporator directly returns to the primary compressor 1, while the secondary compressor 2 and the secondary condenser 4 are in a non-connected state and no refrigerant will flow through. Thus, the air-conditioning unit can switch the operating mode according to needs, and has both single-stage operation and multi-stage operation modes, improving the applicability of the equipment and the actual use efficiency.

[0024] A gas-liquid separator 11 is connected to the pipeline on the intake side of the primary compressor 1, and both the first branch 121 and the pipeline on the outlet side of the secondary evaporator 9 are connected to the inlet side of the gas-liquid separator 11. Due to the poor control of the liquid volume in the ejector 10, the primary compressor 1 is prone to sucking liquid. By setting the gas-liquid separator 11, this problem can be effectively avoided.

[0025] The heat exchanger is specifically a plate heat exchanger 7. The outlet end of the primary condenser 3 is divided into two heat exchange branches, namely the first heat exchange branch 71 and the second heat exchange branch 72. The first heat exchange branch 71 passes through (connects to) the plate heat exchanger 7 and is connected to the primary evaporator 8. The second heat exchange branch 72 passes through (connects to) the plate heat exchanger 7 and is connected to the secondary compressor 2. A second throttle valve 6 is provided on a section of the second heat exchange branch near the inlet side of the plate heat exchanger 7, and a first throttle valve 5 is provided on a section of the first heat exchange branch near the outlet side of the plate heat exchanger 7. The presence of the plate heat exchanger 7 and the second throttle valve 6 can accurately control the refrigerant amount and refrigerant temperature entering the secondary compressor 2, improving the system reliability.

[0026] The primary condenser 3 is connected to the return pipe of medium and low temperature heating hot water and the supply pipe of medium and low temperature heating hot water. The secondary condenser 4 is connected to the return pipe of high temperature heating hot water and the supply pipe of high temperature heating hot water. And a middle pipe is connected between the outlet pipe of the primary condenser 3 (i.e., the supply pipe of medium and low temperature heating hot water) and the inlet pipe of the secondary condenser 4 (the return pipe of high temperature heating hot water). A middle switch valve 14 is provided on the middle pipe, and the middle switch valve 14 is closed when switching to the conventional temperature mode. The secondary evaporator 9 is simultaneously connected to the return pipe of medium and low temperature heating hot water for heat exchange, improving the heat exchange efficiency.

[0027] The above-mentioned switch valves are all solenoid valves, so that they can be controlled by an electric control method to realize the automatic switching of modes.

[0028] In a specific embodiment, the above-mentioned air-conditioning system is an air-source heat pump unit. That is, the primary evaporator 8 is an air-side heat exchanger.

[0029] The following is a specific description of the two modes:

[0030] The first is the large temperature difference mode. Under the demand of a large temperature difference, the ambient temperature is very low and the hot water temperature to be produced is very high. At this time, the large temperature difference demand mode is started. Specifically, as Figure 2 shown, all the components in the figure participate in the cycle. The second switch valve 13, the middle switch valve 14, and the third switch valve 15 are opened, and the first switch valve is closed. Specifically, as Figure 2 shown.

[0031] ① First, produce medium and low temperature water: The high-temperature and high-pressure refrigerant gas generated by the primary compressor 1 enters the primary condenser 3 to exchange heat with water to produce medium and low temperature water. After condensation, it passes through two heat exchange branches. A part of the refrigerant is throttled by the second throttle valve 6 and exchanges heat in the plate heat exchanger 7 to form a subcooled refrigerant. Another part of the refrigerant exchanges heat in the plate heat exchanger 7 and then is throttled, depressurized, and cooled by the first throttle valve 5 and enters the primary evaporator 8 to exchange heat with the low-grade air source. After absorbing the heat in the air, it forms a low-pressure and low-temperature refrigerant gas.

[0032] Then, high-temperature hot water is produced: After heat exchange is completed in the plate heat exchanger 7 in the above item ①, the branched refrigerant forms a high-pressure and medium-temperature refrigerant gas. This part of the gas enters the second-stage compressor 2 for compression. At this time, the temperature of the refrigerant gas is higher than the temperature of the refrigerant gas discharged from the first-stage compressor 1 in item ①. It enters the second-stage condenser 4 and continues to exchange heat with the medium-low temperature water coming out of the first-stage condenser in item ① to produce high-temperature hot water. After condensation, it forms a high-pressure and high-temperature refrigerant liquid, enters the ejector, mixes with the low-pressure and low-temperature refrigerant gas coming out of the first-stage evaporator 8 in item ①, and enters the second-stage evaporator 9 to exchange heat with water (this part of water is taken from a part of the medium-low temperature hot water return water of the first-stage condenser 3), and after absorbing the heat of the water, it enters the gas-liquid separator 11 for gas-liquid separation and then enters the first-stage compressor 1.

[0033] In the ejector 10, on the one hand, the high-pressure and high-temperature refrigerant liquid from the second-stage condenser 4 is throttled. On the other hand, the low-pressure and low-temperature refrigerant gas coming out of the first-stage evaporator 8 in item ① recovers the expansion work of the throttling of the high-pressure and high-temperature refrigerant liquid, increases the suction pressure of the first-stage compressor 1, reduces the compressor pressure ratio, and improves the system energy efficiency.

[0034] So far, the large temperature difference air source heat pump heating scheme is completed.

[0035] The second is the conventional temperature mode. When switching to the conventional temperature heating mode, the first switching valve 12 is opened, and the second switching valve, the intermediate switching valve, the third switching valve, and the second-stage compressor 2 are closed. Specifically, as Figure 3 shown.

[0036] Producing medium-low temperature water: The high-temperature and high-pressure refrigerant gas generated by the first-stage compressor 1 enters the first-stage condenser 3 to exchange heat with water to produce medium-low temperature water. After condensation, it is throttled, depressurized, and cooled by the first throttle valve 5 and then enters the first-stage evaporator 8 to exchange heat with the low-grade air source, absorbs the heat in the air to form a low-pressure and low-temperature refrigerant gas, and after gas-liquid separation by the gas-liquid separator, it enters the first-stage compressor 1 for compression, and so on in a cycle.

[0037] By improving the pipeline structure of the unit, the present invention can realize the switching between large temperature difference heating and conventional heating, and meet the heating demand in the whole heating season. In the large temperature difference mode, high-temperature hot water can be produced for heating water supply at ultra-low ambient temperatures; while at the beginning stage of the heating season, the ambient temperature is relatively high, and medium-low temperature hot water can meet the demand. At this time, the participation of components is reduced, the system pressure drop is reduced, and the system operation performance is improved.

[0038] It should be noted that the terms used above 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, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0039] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0040] In the description of the present application, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as limiting the protection scope of the present application; the orientation words "inner, outer" refer to the inside and outside relative to the contour of each component itself.

[0041] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper" etc. may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figure is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations for the spatial relative descriptions used herein will be made accordingly.

[0042] In addition, it should be noted that the use of terms such as "first", "second" etc. to limit components is only for the convenience of differentiating the corresponding components. Without further statement, the above terms have no special meaning, and thus should not be construed as limiting the protection scope of the present application.

[0043] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An air conditioning unit, comprising: A primary compressor, a primary condenser and a heat exchanger connected by pipelines. The pipeline on the outlet side of the primary condenser is divided into two heat exchange branches to connect the heat exchanger. One heat exchange branch coming out of the heat exchanger is sequentially connected to a primary evaporator and an ejector, and the other heat exchange branch is sequentially connected to a secondary compressor, a secondary condenser and the ejector. The pipeline on the outlet side of the ejector is sequentially connected to a secondary evaporator and the primary compressor. It is characterized in that a breakable first branch is connected between the outlet side of the primary evaporator and the outlet side of the secondary evaporator, and a second switching valve is provided on the pipeline between the secondary condenser and the ejector; a first switching valve is provided on the first branch; The outlet side of the primary condenser is divided into two heat exchange branches, namely a first heat exchange branch and a second heat exchange branch. The first heat exchange branch is connected to the heat exchanger and the primary evaporator, and the second heat exchange branch is connected to the heat exchanger and the secondary compressor. A second throttle valve is provided on a section of the second heat exchange branch close to the inlet side of the heat exchanger, and a first throttle valve is provided on a section of the first heat exchange branch close to the outlet side of the heat exchanger.

2. The air conditioner unit according to claim 1, characterized in that, A gas-liquid separator is connected to the intake pipeline of the primary compressor.

3. The air conditioner unit according to claim 1, characterized in that, The heat exchanger is a plate heat exchanger.

4. The air conditioner unit according to claim 1, wherein, An intermediate pipeline is connected between the water supply pipeline of the primary condenser and the water return pipeline of the secondary condenser, and an intermediate switching valve is provided on the intermediate pipeline.

5. The air-conditioning unit according to claim 1, characterized in that, The water return pipeline of the secondary evaporator is in parallel with the water return pipeline of the primary condenser.

6. The air-conditioning unit according to claim 1, characterized in that A third switching valve is provided on the connecting pipeline between the primary evaporator and the ejector.

7. The air conditioner unit according to claim 1, 4 or 6, characterized in that, The switching valve is a solenoid valve.

8. The air conditioning unit according to claim 1, characterized in that The air-conditioning unit is an air-source heat pump unit.

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