CN-122015189-A - Multi-split air conditioning system

CN122015189ACN 122015189 ACN122015189 ACN 122015189ACN-122015189-A

Abstract

The application discloses a multi-split air conditioning system, and belongs to the technical field of air conditioners. The system comprises an outdoor unit, an indoor water end and an air processing unit, wherein the controller is configured to determine that the air processing unit is a refrigeration main body or a heating main body, control a second four-way valve based on refrigeration heat exchange control logic to enable the second four-way valve to be communicated with the outdoor heat exchanger and the reheating heat exchanger and control an expansion valve of the outdoor heat exchanger to be in a non-cut-off state if the air processing unit is the refrigeration main body, control the expansion valve of the outdoor heat exchanger to be in the non-cut-off state based on heating heat exchange control logic and control the operation of an outdoor fan based on a preset rotating speed if the air processing unit is the heating main body. The air conditioning system provided by the application can realize heat transfer of the reheating heat exchanger and the dehumidifying heat exchanger and basic temperature and humidity regulation by only identifying the refrigerating and heating main bodies and carrying out different strategies of four-way valve switching and outdoor heat exchanger expansion valve control.

Inventors

JING XU
LI JUNFEI
LI YAJUN
CAO FALI
GENG SHICHAO
LI ZHAOHUI
LI YUQIAO

Assignees

青岛海信日立空调系统有限公司

Dates

Publication Date: 20260512
Application Date: 20260113

Claims (10)

1. A multi-split air conditioning system, comprising: an outdoor unit having a compressor, an outdoor heat exchanger, a first four-way valve, and a second four-way valve, wherein a first end of the first four-way valve is connected to an exhaust side of the compressor, a fifth end of the second four-way valve is connected to the first end of the first four-way valve and to a seventh end of the second four-way valve, and a sixth end of the second four-way valve is connected to the outdoor heat exchanger and to an eighth end of the second four-way valve; An indoor unit having an indoor heat exchanger; the indoor water tail end is connected with the compressor through a high-pressure pipeline and is connected with the outdoor heat exchanger through a liquid pipe, and an expansion valve of the outdoor heat exchanger is in a cut-off state; an air treatment unit which is provided with a dehumidifying heat exchanger and a reheating heat exchanger, wherein the first end of the dehumidifying heat exchanger and the first end of the reheating heat exchanger are connected with a liquid pipe at the tail end of indoor water, The second end of the dehumidifying heat exchanger is connected with the air suction side of the compressor, the fourth end of the first four-way valve and the eighth end of the second four-way valve through a low-pressure pipeline, and the third end of the first four-way valve is communicated with the fourth end; The second end of the reheating heat exchanger is connected with the second end of the first four-way valve through a high-low pressure switching pipeline, and the second end of the first four-way valve is communicated with the first end; A controller configured to: Determining the air treatment unit as a refrigeration main body or a heating main body; if the air processing unit is a refrigeration main body, controlling the second four-way valve based on refrigeration heat exchange control logic to enable the second four-way valve to be communicated with the outdoor heat exchanger and the reheat heat exchanger, and controlling an expansion valve of the outdoor heat exchanger to be in a non-cut-off state; if the air processing unit is a heating main body, the expansion valve of the outdoor heat exchanger is controlled to be in a non-cut-off state based on heating heat exchange control logic, and the operation of the outdoor fan is controlled based on a preset rotating speed.
2. The multi-split air conditioning system of claim 1, wherein the fifth end of the second four-way valve is controlled to communicate with the sixth end and the seventh end of the second four-way valve is controlled to communicate with the eighth end based on refrigeration heat exchange control logic.
3. The multi-split air conditioning system of claim 2, wherein the controller is further configured to: if the air processing unit is a heating main body, controlling the opening of the expansion valve to normalize the real-time superheat degree Approaching or equal to the normalized target superheat degree 。
4. The multi-split air conditioning system of claim 3, wherein the controller is further configured to: acquiring the temperature of the air pipe of the outdoor heat exchanger Temperature of liquid mixing pipe Based on the temperature of the trachea Temperature of liquid mixing pipe Determining the real-time superheat degree; According to the outdoor side temperature return of the outdoor heat exchanger And vaporization temperature Normalizing the real-time superheat degree to obtain the normalized real-time superheat degree 。
5. The multi-split air conditioning system of claim 3, wherein the controller is further configured to: Determining the normalized heat exchange amount of the outdoor heat exchanger as an evaporator The normalized heat exchange amount Substituting the target superheat degree into a normalized target superheat degree model, and calculating to obtain the normalized target superheat degree 。
6. The multi-split air conditioning system of claim 5, wherein the controller is further configured to: Obtaining the maximum heat exchange amount of the outdoor heat exchanger serving as an evaporator And minimum heat exchange amount ; Based on the maximum heat exchange amount And minimum heat exchange amount Determining a maximum evaporation heat exchange amount difference value; Demand heat exchange amount based on the outdoor heat exchanger as an evaporator With the minimum heat exchange amount Determining the difference in heat exchange amount of the evaporation demand; determining the normalized heat exchange amount based on a quotient of the evaporation demand heat exchange amount difference and the maximum evaporation heat exchange amount difference 。
7. The multi-split air conditioning system of any of claims 1-6, wherein the controller is further configured to: if the air handling unit is a refrigeration main body, controlling the opening of the expansion valve to normalize the real-time supercooling degree Approaching or equal to the normalized target supercooling degree 。
8. The multi-split air conditioning system of claim 6, wherein the controller is further configured to: Acquiring a saturation temperature corresponding to the high pressure of the outdoor heat exchanger Temperature of liquid mixing pipe Based on saturation temperature Temperature of liquid mixing pipe Determining the real-time supercooling degree; According to the outdoor side temperature return of the outdoor heat exchanger Normalizing the real-time superheat degree to obtain the normalized real-time supercooling degree 。
9. The multi-split air conditioning system of claim 6, wherein the controller is further configured to: determining normalized heat exchange capacity of the outdoor heat exchanger as a condenser The normalized heat exchange amount Substituting the normalized target supercooling degree model, and calculating to obtain the normalized target supercooling degree 。
10. The multi-split air conditioning system of claim 9, wherein the controller is further configured to: obtaining the maximum heat exchange capacity of the outdoor heat exchanger serving as a condenser And minimum heat exchange amount ; Based on the maximum heat exchange amount And minimum heat exchange amount Determining a maximum condensation heat exchange amount difference value; demand heat exchange amount based on the outdoor heat exchanger as a condenser With the minimum heat exchange amount Determining a difference in condensing demand heat exchange amount; determining the normalized heat exchange amount based on a quotient of the condensation demand heat exchange amount difference and the maximum condensation heat exchange amount difference 。

Description

Multi-split air conditioning system Technical Field The application relates to the technical field of air conditioners, in particular to a multi-split air conditioning system. Background In a multi-split air conditioning system, a complete cooling and heating medium circulation system is formed by connecting one or more outdoor units with a plurality of indoor terminal devices through pipelines, so that the temperature and humidity of air in a plurality of areas are regulated. Unlike the conventional single-function air conditioning system, the multi-split air conditioning system has higher flexibility and integration, and can be simultaneously connected with various types of terminal equipment, such as a water system terminal, an air handling unit (AIR HANDLING Units, AHU) dehumidification reheat terminal, a fresh air system terminal and a conventional refrigeration/heating indoor unit terminal. The system can simultaneously support various operation modes such as hot water production, cooling and dehumidification, conventional air conditioning and refrigeration, and the like, and is widely applied to large-scale buildings, commercial places or high-precision process environments requiring regional control or complex climate requirements. AHU equipment, as a critical air handling terminal in a system, is typically configured with a condenser and evaporator to perform dehumidification and reheat functions to regulate the temperature and humidity of the air. In the multi-split air conditioning system provided with the AHU equipment, when the AHU equipment is connected with the outdoor unit, the system calculates the required cold and heat quantity demand according to the real-time parameters and the target air parameters of inlet air, and adjusts and controls the operation frequency of the compressor based on the cold and heat quantity demand so as to realize corresponding air conditioning. However, in practical applications, when the system faces the requirement of accurate temperature and humidity control, a problem that the load requirements of the reheat heat exchanger and the dehumidification heat exchanger are different significantly often occurs. Because the compressors, the dehumidifying heat exchangers and the reheating heat exchangers in the system structure are connected in series, the system can be regulated only by a unified compressor control target, so that the output capacity of the compressor is difficult to be matched with the actual requirements of the heat exchangers synchronously. The problem of capability mismatch directly influences the temperature and humidity control effect of the tail end air treatment unit, and is more obvious especially in a scene with higher temperature and humidity control precision requirements. Therefore, in order to improve the response capability and control accuracy of temperature and humidity regulation under the existing air conditioning system architecture with the heat recovery function, a control method capable of coordinating the operation states of the compressor and the related heat exchange units according to the actual requirements of the tail ends is needed, so as to achieve a more refined temperature and humidity regulation target. Disclosure of Invention The application provides a multi-split air conditioning system, which comprises: an outdoor unit having a compressor, an outdoor heat exchanger, a first four-way valve, and a second four-way valve, wherein a first end D1 of the first four-way valve is connected to an exhaust side of the compressor, a fifth end D2 of the second four-way valve is connected to the first end D1 of the first four-way valve and to a seventh end E2 of the second four-way valve, and a sixth end C2 of the second four-way valve is connected to the outdoor heat exchanger and to an eighth end S2 of the second four-way valve; An indoor unit having an indoor heat exchanger; the indoor water tail end is connected with the compressor through a high-pressure pipeline and is connected with the outdoor heat exchanger through a liquid pipe, and an expansion valve of the outdoor heat exchanger is in a cut-off state; an air treatment unit which is provided with a dehumidifying heat exchanger and a reheating heat exchanger, wherein the first end of the dehumidifying heat exchanger and the first end of the reheating heat exchanger are connected with a liquid pipe at the tail end of indoor water, The second end of the dehumidifying heat exchanger is connected with the air suction side of the compressor, the fourth end S1 of the first four-way valve and the eighth end S2 of the second four-way valve through a low-pressure pipeline, and the third end E1 of the first four-way valve is communicated with the fourth end S1; The second end of the reheating heat exchanger is connected with the second end C1 of the first four-way valve through a high-low pressure switching pipeline, and the second end C1 of the first four-way valve is communica