A heat pump multi-connected system and a control method for heating standby waste heat utilization thereof

Abstract

The application discloses a heat pump multi-connected system and a control method for waste heat utilization in heating standby mode, and belongs to the field of heat pump multi-connected system. When the heating mode is started, the electronic expansion valve EXV1 is opened according to the initial opening degree, and the electronic expansion valve EXV1 is controlled. The waste heat in the heating standby mode or the residual heat of the started indoor unit is stored in the water tank, the part of the refrigerant entering the compressor is heated and warmed up in the water tank again, the superheat degree of the jet refrigerant entering the compressor is improved, the overall performance of the system is improved, and the purpose of energy saving and consumption reduction is achieved.

Description

Technical Field

[0001] This invention relates to a heat pump multi-split system and a control method for utilizing waste heat during heating and standby. Background Technology

[0002] Currently, when multi-split air conditioners are operating under partial load heating, all indoor units in the system are identical due to the high-pressure side connection. Considering the reliability of the unit's oil return, the electronic expansion valve of the liquid pipe design of the multi-split indoor unit will have a small flow opening. In heating mode, the high-temperature and high-pressure gas from the main unit enters all indoor units in the system. The indoor units in use provide heat to the room, but the indoor units not in use waste heat, ultimately resulting in high energy consumption and high operating costs for the entire system. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a heat pump multi-split system and a control method for utilizing waste heat during heating and standby, effectively solving the problems mentioned in the background art.

[0004] The technical solution adopted in this invention is:

[0005] A heat pump multi-split system includes an outdoor unit, an indoor unit, and a water tank. The outdoor unit is equipped with an economizer at the liquid outlet. The main circuit of the economizer is connected to the liquid inlets of both the outdoor and indoor units. The liquid circuit of the indoor unit has a first branch at the front end of the liquid inlet. The first branch passes through the water tank and returns to the front throttling port of the main electronic expansion valve EXV2 of the outdoor unit. The liquid circuit of the outdoor unit has a second branch. The second branch passes sequentially through the electronic expansion valve EXV1, the auxiliary circuit of the economizer, and the water tank before returning to the vapor injection enthalpy port of the compressor in the outdoor unit.

[0006] Preferably, the first branch line is equipped with a first heat exchanger in the water tank, and the second branch line is equipped with a second heat exchanger in the water tank.

[0007] Preferably, the second branch is equipped with a temperature sensor TH4 at the outlet of the electronic expansion valve EXV1, the main outlet of the economizer is equipped with a temperature sensor TH5, and the compressor of the outdoor unit is equipped with a temperature sensor TH6 at the jet enthalpy inlet.

[0008] A control method for utilizing waste heat during heating standby in a heat pump multi-split system, wherein when the heating mode is activated, the electronic expansion valve EXV1 opens according to its initial opening degree, and the electronic expansion valve EXV1 is controlled as follows:

[0009] If the temperature detected by temperature sensor TH6 is greater than the temperature detected by temperature sensor TH5 + 3℃, then the electronic expansion valve EXV1 is controlled to increase its opening by the value of the temperature detected by temperature sensor TH6 minus (the temperature detected by temperature sensor TH5 + 3℃), until the electronic expansion valve EXV1 reaches its maximum opening. If the temperature detected by temperature sensor TH6 is less than the temperature detected by temperature sensor TH5 + 3℃, then the electronic expansion valve EXV1 is controlled to decrease its opening by the value of (the temperature detected by temperature sensor TH5 + 3℃) minus the temperature detected by temperature sensor TH6, until the electronic expansion valve EXV1 reaches its minimum opening. If the temperature detected by temperature sensor TH6 equals the temperature detected by temperature sensor TH5 + 3℃, then the electronic expansion valve EXV1 is controlled to maintain its current opening.

[0010] This invention stores the residual heat from standby heating or the residual heat from the indoor unit when it is turned on in a water tank. This allows the refrigerant injected into the compressor to absorb heat and heat up again in the water tank, increasing the superheat of the refrigerant entering the compressor. This improves the overall performance of the system and achieves the goal of energy saving and consumption reduction. Attached Figure Description

[0011] Figure 1 This is a system schematic diagram of the present invention. Detailed Implementation

[0012] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0013] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0014] Furthermore, in the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0015] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, unless explicitly defined otherwise.

[0016] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0017] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0018] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0019] Example 1

[0020] A heat pump multi-split system includes an outdoor unit, an indoor unit, and a water tank. The outdoor unit is equipped with an economizer at the liquid outlet. The main circuit of the economizer is connected to the liquid inlets of both the outdoor and indoor units. The liquid circuit of the indoor unit has a first branch at the front end of the liquid inlet. The first branch passes through the water tank and returns to the front throttling port of the main electronic expansion valve EXV2 of the outdoor unit. The liquid circuit of the outdoor unit has a second branch. The second branch passes sequentially through the electronic expansion valve EXV1, the auxiliary circuit of the economizer, and the water tank before returning to the vapor injection enthalpy port of the compressor in the outdoor unit.

[0021] Preferably, the first branch line is equipped with a first heat exchanger in the water tank, and the second branch line is equipped with a second heat exchanger in the water tank.

[0022] Preferably, the second branch is equipped with a temperature sensor TH4 at the outlet of the electronic expansion valve EXV1, the main outlet of the economizer is equipped with a temperature sensor TH5, and the compressor of the outdoor unit is equipped with a temperature sensor TH6 at the jet enthalpy inlet.

[0023] A control method for utilizing waste heat during heating standby in a heat pump multi-split system, wherein when the heating mode is activated, the electronic expansion valve EXV1 opens according to its initial opening degree, and the electronic expansion valve EXV1 is controlled as follows:

[0024] If the temperature detected by temperature sensor TH6 is greater than the temperature detected by temperature sensor TH5 + 3℃, then the electronic expansion valve EXV1 is controlled to increase its opening by the value of the temperature detected by temperature sensor TH6 minus (the temperature detected by temperature sensor TH5 + 3℃), until the electronic expansion valve EXV1 reaches its maximum opening. If the temperature detected by temperature sensor TH6 is less than the temperature detected by temperature sensor TH5 + 3℃, then the electronic expansion valve EXV1 is controlled to decrease its opening by the value of (the temperature detected by temperature sensor TH5 + 3℃) minus the temperature detected by temperature sensor TH6, until the electronic expansion valve EXV1 reaches its minimum opening. If the temperature detected by temperature sensor TH6 equals the temperature detected by temperature sensor TH5 + 3℃, then the electronic expansion valve EXV1 is controlled to maintain its current opening.

[0025] Working principle of the invention:

[0026] The outdoor unit's compressor generates high-temperature, high-pressure gaseous refrigerant, which is then sent to the indoor unit for heating. After heat exchange, the high-temperature, high-pressure gaseous refrigerant becomes medium-temperature, medium-pressure liquid refrigerant and splits into two paths. One path enters the liquid inlets of both the outdoor and indoor units, while the other path enters the water tank through the first branch. There, it passes through the first heat exchanger, where it stores residual heat from standby or the indoor unit's heat during operation. The refrigerant then returns to the throttling port of the main electronic expansion valve EXV2, where it is throttled. It then passes through the outdoor heat exchanger to absorb heat from the air before returning to the compressor for further circulation. Simultaneously, the electronic expansion valve EXV1 takes a small amount of refrigerant from the outdoor unit's liquid circuit, passes through the economizer's auxiliary path, and enters the water tank. There, it passes through the second heat exchanger, which raises the refrigerant's temperature. The refrigerant then returns to the compressor's vapor injection port, thereby increasing the superheat at the vapor injection port, improving heating capacity, and reducing energy consumption.

[0027] Finally, it should be noted that the above examples are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this invention should be considered within the scope of protection of this invention.

Claims

1. A heat pump multi-split system, characterized in that, The system includes an outdoor unit, an indoor unit, and a water tank. The outdoor unit is equipped with an economizer at the liquid outlet. The main circuit of the economizer is connected to the liquid inlets of both the outdoor and indoor units. The liquid circuit of the indoor unit has a first branch at the front end of the liquid inlet. The first branch passes through the water tank and returns to the front throttling port of the main electronic expansion valve EXV2 of the outdoor unit. The liquid circuit of the outdoor unit has a second branch. The second branch passes sequentially through the electronic expansion valve EXV1, the auxiliary circuit of the economizer, and the water tank before returning to the vapor injection enthalpy port of the compressor in the outdoor unit.

2. The heat pump multi-split system according to claim 1, characterized in that, The first branch line is equipped with a first heat exchanger inside the water tank, and the second branch line is equipped with a second heat exchanger inside the water tank.

3. A heat pump multi-split system according to claim 2, characterized in that, The second branch is equipped with a temperature sensor TH4 at the outlet of the electronic expansion valve EXV1, the main outlet of the economizer is equipped with a temperature sensor TH5, and the compressor of the outdoor unit is equipped with a temperature sensor TH6 at the jet enthalpy inlet.

4. A control method for utilizing standby waste heat in a heat pump multi-split system as described in claim 3, characterized in that, When the heating mode is activated, the electronic expansion valve EXV1 opens to its initial opening degree, and the electronic expansion valve EXV1 is controlled as follows: If the temperature detected by temperature sensor TH6 is greater than the temperature detected by temperature sensor TH5 + 3℃, then the electronic expansion valve EXV1 is controlled to increase its opening by the value of the temperature detected by temperature sensor TH6 minus (the temperature detected by temperature sensor TH5 + 3℃), until the electronic expansion valve EXV1 reaches its maximum opening. If the temperature detected by temperature sensor TH6 is less than the temperature detected by temperature sensor TH5 + 3℃, then the electronic expansion valve EXV1 is controlled to decrease its opening by the value of (the temperature detected by temperature sensor TH5 + 3℃) minus the temperature detected by temperature sensor TH6, until the electronic expansion valve EXV1 reaches its minimum opening. If the temperature detected by temperature sensor TH6 equals the temperature detected by temperature sensor TH5 + 3℃, then the electronic expansion valve EXV1 is controlled to maintain its current opening.

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