Intelligent defrosting control method for air-cooled single-heating type air conditioning unit

Abstract

The invention discloses an intelligent defrosting control method for an air-cooled single-heat type air conditioning unit, which comprises the following steps: in a heat supply operation state, a low-pressure liquid refrigerant is output through an electronic expansion valve, sequentially flows through a mixing box and a refrigerant distributor to enter a plurality of first heat exchange assemblies, is collected to a gas collecting pipe after absorbing heat and gasifying, and then flows back to a compressor; when the system enters a defrosting mode, the multiple first heat exchange assemblies are sequentially switched to the defrosting state according to the set sequence, and the preferable sequence is that the assemblies with the thermal interference buffering function are arranged; a target assembly in a defrosting state receives a high-temperature gaseous refrigerant led out from an outlet of a condenser by opening a corresponding defrosting bypass electromagnetic valve, and the high-temperature gaseous refrigerant is led into a defrosting control valve and then enters a gas phase inlet; the refrigerant releases heat in the assembly to melt the frost layer to form a liquid state or a gas-liquid mixed state, and finally flows into the mixing box to be mixed with a liquid working medium output by the throttling device. According to the defrosting control method, the air conditioning unit can operate efficiently and stably without interruption of heating.

Description

Technical Field

[0001] This invention relates to the field of air conditioning heat pump control technology, and in particular to an intelligent defrosting control method for air-cooled single-heating air conditioning units. Background Technology

[0002] Air-cooled single-heat-source air conditioning units are heat pump systems that use air as a heat source, and are widely used in building heating, hot water supply, and other fields. During winter heating operation, frost easily forms on the surface of the outdoor heat exchanger. The formation of frost significantly reduces heat exchange efficiency, affecting the stability and energy efficiency of the unit's operation. Therefore, timely and effective defrosting of the heat exchanger surface is one of the key issues to ensure the efficient operation of air-cooled heat pump units.

[0003] In existing technologies, defrosting methods for air-cooled heat pumps mostly employ reverse circulation defrosting, which involves changing the flow direction of the refrigerant in the system, causing the high-temperature, high-pressure gaseous refrigerant to flow backward into the outdoor heat exchanger, thereby melting the frost. To achieve reverse circulation defrosting, a four-way valve or three-way valve is often used in conjunction with a solenoid valve to switch the gas-liquid pathway in the heat exchanger. However, existing defrosting control methods generally suffer from the following problems: On the one hand, in the traditional structure, defrosting hot gas is often injected from the liquid side of the heat exchanger, which leads to uneven heating of the heat exchanger, low defrosting efficiency, and easy occurrence of incomplete defrosting or local liquid accumulation, increasing the risk of the compressor operating with liquid.

[0004] On the other hand, the traditional reverse circulation defrosting mode usually defrosts all heat exchangers at the same time. During the defrosting period, the system needs to partially or completely stop heating, resulting in heating interruption and affecting user experience. At the same time, the simultaneous release of hot air from multiple heat exchangers may cause thermal interference, leading to instability in the defrosting process.

[0005] In addition, the defrosting control logic in some systems is quite complex, involving multiple mechanical linkage components. This not only makes the control system structure complex and costly, but also results in poor stability and high maintenance difficulty.

[0006] Therefore, there is an urgent need for an intelligent defrosting control method that provides uniform heat exchange, better defrosting effect, sequential defrosting of each heat exchanger, and does not affect the overall stable operation of the system during the defrosting process, in order to solve the above-mentioned problems of existing technologies. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide an intelligent defrosting control method for air-cooled single-heating air conditioning units. This control method achieves better defrosting performance, enables sequential defrosting of each heat exchanger, and ensures the overall stability of the system operation.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for intelligent defrosting control of an air-cooled single-heating air conditioning unit includes the following steps: S1: When the unit is in normal heating operation, the low-pressure liquid refrigerant is output by the electronic expansion valve, flows through the mixing box and refrigerant distributor in sequence, enters multiple first heat exchange components, absorbs heat and vaporizes in the heat exchange components, and then collects into the gas collection pipe through the gas phase flow path, enters the gas-liquid separator and flows back to the compressor suction end. S2: When the system enters the defrost mode, control multiple first heat exchange components to switch to the defrost state in a set order. The preferred order is one in which adjacent heat exchange components have thermal interference buffers. S3: For the target heat exchange component in the defrost state, control the opening of its corresponding defrost bypass solenoid valve, so that the high temperature and high pressure gaseous refrigerant is drawn out from the condenser outlet side, introduced into the first input port of the defrost control valve through the solenoid valve, and output from the second output port into the gas phase inlet branch of the target heat exchange component. S4: High-temperature gaseous refrigerant releases heat in the target heat exchange component to melt the frost layer, and the resulting liquid or gas-liquid mixed refrigerant is introduced into the mixing box through the liquid phase outlet branch. S5: In the mixing chamber, liquid or gas-liquid mixed refrigerant is mixed with low-pressure liquid refrigerant from the throttling device to suppress the risk of liquid slugging of the compressor by residual gaseous components; The defrosting operation is achieved by a combination of a defrosting bypass solenoid valve and a defrosting control valve, and the control process is automatically executed based on a preset logical sequence.

[0009] Furthermore, in step S2, the components in the first heat exchange assembly that have not started defrosting continue to maintain heating operation.

[0010] Furthermore, the control method also includes the following steps: Before step S2, the frosting status parameters, ambient temperature, and corresponding cumulative running time of each first heat exchange component are obtained, and a comprehensive judgment is made based on the above parameters. When the preset defrost triggering conditions are met, step S2 is executed to control the corresponding defrost bypass solenoid valve to open and start the defrost process.

[0011] Furthermore, in step S4, the temperature of the liquid or gas-liquid mixture refrigerant is monitored, and if it exceeds a set upper limit, the time for it to mix with the working fluid output by the throttling device is delayed to enhance heat exchange stability.

[0012] Furthermore, multiple first heat exchange components are finned heat exchangers arranged in a V-shape, sequentially arranged along the airflow direction of the unit.

[0013] Furthermore, in the defrosting mode, multiple first heat exchange components enter the defrosting state sequentially according to the priority order of reducing thermal interference, with the preferred order being the front component, the diagonal component, the side component, and the rear component.

[0014] Furthermore, during defrosting, the heat exchange components receive high-temperature gaseous working fluid from the condenser section of the refrigeration system via an independent bypass path.

[0015] Furthermore, each first heat exchange component is provided with at least one temperature sensor or frost detection sensor to provide a defrost start signal.

[0016] Furthermore, the mixing chamber is equipped with a turbulence-prone structure to promote thorough mixing of the recirculating working fluid and the throttling working fluid, thereby reducing the impact of gas-liquid unevenness on system operation.

[0017] Furthermore, the defrosting process supports a manual triggering mode, allowing the operator to force the defrosting steps in case of automatic control failure or special maintenance conditions.

[0018] The aforementioned intelligent defrosting control method for air-cooled single-heating air conditioning units utilizes high-temperature gaseous refrigerant that sequentially enters each target heat exchanger via an independent bypass path for defrosting, achieving on-demand, batch, and automated defrosting control. Compared to traditional reverse-cycle defrosting methods, this method avoids problems such as uneven heating of heat exchangers, severe system thermal interference, and overall heating interruption, significantly improving defrosting efficiency and system operational stability, reducing the risk of compressor liquid slugging, and maintaining continuous heating capacity in complex environments, demonstrating higher intelligence, reliability, and applicability. Attached Figure Description

[0019] Figure 1 This is a structural schematic diagram of an air-cooled single-heating air conditioning unit provided according to the present invention; Figure 2 This is a flowchart of the intelligent defrosting control method provided by the present invention. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0021] like Figure 1 and Figure 2 As shown, this application provides an intelligent defrosting control method for air-cooled single-heating air conditioning units, including the following steps: S1: When the unit is in normal heating operation, the low-pressure liquid refrigerant is output by the electronic expansion valve 1, flows through the mixing box 2 and the refrigerant distributor 3 in sequence, enters multiple first heat exchange components 4, absorbs heat and vaporizes in the heat exchange components 4, and then collects into the gas collection pipe through the gas phase flow path, and then enters the gas-liquid separator 5 and flows back to the compressor suction end. S2: When the system enters the defrost mode, control multiple first heat exchange components 4 to switch to the defrost state in a set order. The preferred order is one in which adjacent heat exchange components 4 have thermal interference buffers. The order of thermal interference buffer between adjacent heat exchange components refers to prioritizing those heat exchangers that are not physically adjacent when controlling multiple heat exchangers to defrost in sequence. This reduces mutual heat conduction or heat flow interference during the defrosting process and maintains the thermodynamic stability of the system.

[0022] S3: For the target heat exchange component 4 in the defrost state, control the opening of its corresponding defrost bypass solenoid valve 6 so that the high temperature and high pressure gaseous refrigerant is drawn out from the outlet side of the condenser 7, introduced into the first input port of the defrost control valve 8 through the solenoid valve 6, and output from the second output port into the gas phase inlet branch of the target heat exchange component 4. S4: High-temperature gaseous refrigerant releases heat in the target heat exchange component 4 to melt the frost layer, and the resulting liquid or gas-liquid mixed refrigerant is introduced into the mixing box 2 through the liquid phase outlet branch; S5: In mixing chamber 2, liquid or gas-liquid mixed refrigerant is mixed with low-pressure liquid refrigerant from the throttling device to suppress the risk of liquid slugging of the compressor by residual gaseous components; The defrosting operation is achieved by the defrosting bypass solenoid valve 6 and the defrosting control valve 8, and the control process is automatically executed based on a preset logical sequence.

[0023] This method enables defrosting of each heat exchange component 4 individually and sequentially, avoiding thermal interference caused by simultaneous defrosting of multiple heat exchangers and reducing interruptions to conventional heating. Simultaneously, high-temperature gaseous refrigerant is introduced from the condenser 7 outlet and injected into the heat exchange component 4 through an independent gas phase branch, ensuring uniform heating and improving defrosting efficiency. The mixing chamber 2 effectively mitigates the risk of liquid slugging by mixing the reflux and throttling refrigerant, ensuring the compressor's safe operation. The defrosting process can be automatically identified and executed by the system, improving operational intelligence, reducing system complexity, and enhancing maintenance convenience and control stability.

[0024] In step S2, those of the multiple first heat exchange components 4 that have not yet started defrosting continue to operate in heating mode. In this embodiment, the defrosting mode of the air-cooled single-heating air conditioning unit adopts a time-sharing group control strategy, that is, multiple first heat exchange components 4 do not enter the defrosting state simultaneously, but start the defrosting operation one by one according to a set sequence. For heat exchange components 4 that have not yet entered the defrosting process, they remain connected to the main refrigerant circuit, continue to receive low-pressure liquid refrigerant from the electronic expansion valve 1, and undertake the heat absorption task of the heat pump system. In these components, the refrigerant absorbs ambient heat, evaporates, and forms a gaseous state, flowing into the gas collector pipe and returning to the compressor according to the conventional process, maintaining the heating capacity of the indoor space. This control method realizes the parallel operation of defrosting and heating, effectively ensuring uninterrupted system heating.

[0025] The control method also includes the following steps: Before step S2, the frosting status parameters, ambient temperature, and corresponding cumulative running time of each first heat exchange component 4 are obtained, and a comprehensive judgment is made based on the above parameters. When the preset defrost triggering conditions are met, step S2 is executed to control the corresponding defrost bypass solenoid valve 6 to open and start the defrost process.

[0026] The aforementioned data is obtained through temperature sensors, frost sensors, or operating time recording modules, and input into the controller for multi-dimensional analysis. The control system determines whether the conditions for initiating defrosting are met based on the set defrosting trigger logic, such as "temperature difference exceeds a certain threshold," "cumulative operating time exceeds a set cycle," or "frost thickness reaches a warning value." Only when these combined conditions are met is step S2 initiated, controlling the corresponding defrosting bypass solenoid valve 6 to open, thereby orderly implementing the defrosting operation.

[0027] In step S4, the temperature of the liquid or gas-liquid mixed refrigerant is monitored, and if it exceeds a set upper limit, the mixing time between the refrigerant and the working fluid output from the throttling device is delayed. This enhances heat exchange stability, effectively reduces the interference of instantaneous high temperatures from the refrigerant returning during the defrosting process on the system's thermal balance, and prevents problems such as compressor liquid slugging and abnormal refrigerant conditions caused by insufficient mixing or temperature fluctuations. Through this dynamic delayed mixing mechanism, the temperature uniformity and flow stability of the mixed working fluid are improved, thereby enhancing the overall operational safety and heat exchanger lifespan.

[0028] Multiple first heat exchange components 4 are V-shaped finned heat exchangers arranged sequentially along the airflow direction of the unit. This V-shaped finned heat exchanger arrangement improves heat exchange efficiency per unit volume, making the air conditioning unit more compact. It also improves the airflow path and enhances the uniformity of airflow to the heat exchangers, resulting in higher thermal performance in both heating and defrosting modes. Furthermore, the sequential arrangement along the airflow direction facilitates system control of the defrosting process based on airflow direction and heat load sequence, achieving a more stable and controllable operating mode.

[0029] In defrosting mode, multiple first heat exchange components 4 enter the defrosting state sequentially according to the priority order of reducing thermal interference, with the preferred order being the front component, diagonal component, lateral component, and rear component. Through the optimized defrosting sequence of this embodiment, thermal decoupling between the heat exchange components 4 can be achieved, improving defrosting efficiency and system operational stability. Prioritizing the defrosting of the front component can promptly remove obstacles to heat exchange in the first layer, helping to restore the smooth flow of heat on the air intake side. Subsequently, defrosting is advanced according to the diagonal, lateral, and rear layout, which can minimize the interference of defrosting heat release on the operation of surrounding components, especially on sensor temperature measurement and heating load response, thereby improving the accuracy and intelligence of defrosting control and enhancing the user's heating experience during defrosting.

[0030] During defrosting, heat exchange component 4 receives high-temperature gaseous refrigerant from the condenser section of the refrigeration system via an independent bypass path. This independent bypass path ensures that the high-temperature gaseous refrigerant does not interfere with the normal heating process of other undefrosted heat exchange components 4 during defrosting, improving the independence of defrosting control and the overall stability of the system. Simultaneously, it avoids problems such as heat transfer fluid backflow and flow deviation, reducing system dynamic instability caused by pipeline coupling.

[0031] Each first heat exchange component 4 is equipped with at least one temperature sensor or frost detection sensor to provide a defrost start signal. By setting an independent sensor system for each heat exchange component 4, adaptive defrost control based on local conditions is achieved, significantly improving the accuracy and timeliness of defrost triggering. This avoids the energy waste and over-defrosting problems of traditional timed defrosting methods, while reducing the impact of untimely defrosting on the system's heat exchange capacity and improving operating efficiency.

[0032] The mixing chamber 2 is equipped with a turbulence structure to promote thorough mixing of the reflux working fluid and the throttling working fluid, reducing the impact of gas-liquid unevenness on system operation. This turbulence structure significantly improves the mixing uniformity of the working fluid within the mixing chamber 2, reducing potential problems such as liquid slugging, abnormal compressor return gas, or system energy efficiency fluctuations caused by uneven gas-liquid phase distribution. The turbulence mechanism enhances mixing reaction efficiency and response speed, enabling the system to maintain stable operation even when facing rapid changes in the reflux working fluid state during defrosting, effectively strengthening the system's anti-disturbance capability and dynamic stability.

[0033] The defrosting process supports a manual triggering mode, allowing the operator to force the defrosting steps in case of automatic control failure or special maintenance conditions. This implementation provides a fault-tolerance and recovery mechanism for the defrosting system, ensuring normal defrosting operations can still be performed manually even in the event of automatic control failure or emergency situations, thus improving system reliability and maintenance convenience. It is particularly suitable for initial commissioning, on-site troubleshooting, operation in special environments, or experimental verification phases, ensuring that system operation does not stop due to intelligent control failure.

[0034] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for intelligent defrosting control of an air-cooled single-heating air conditioning unit, characterized in that, Includes the following steps: S1: When the unit is in normal heating operation, the low-pressure liquid refrigerant is output by the electronic expansion valve (1), flows through the mixing box (2) and refrigerant distributor (3) in sequence, enters multiple heat exchange components (4), absorbs heat and vaporizes in the heat exchange components (4), and is collected into the gas collection pipe through the gas phase flow path, then enters the gas-liquid separator (5) and flows back to the compressor suction end; S2: When the system enters the defrost mode, the multiple heat exchange components (4) are controlled to switch to the defrost state in a set order. The order is preferably one in which there is thermal interference buffer between adjacent heat exchange components (4). S3: For the target heat exchange component (4) in the defrost state, control the corresponding defrost bypass solenoid valve (6) to open, so that the high temperature and high pressure gaseous refrigerant is drawn out from the outlet side of the condenser (7), introduced into the first input port of the defrost control valve (8) through the solenoid valve (6), and output from the second output port into the gas phase inlet branch of the target heat exchange component (4); S4: The high-temperature gaseous refrigerant releases heat in the target heat exchange component (4) to melt the frost layer, and the resulting liquid or gas-liquid mixed refrigerant is introduced into the mixing box (2) through the liquid phase outlet branch. S6: In the mixing chamber (2), the liquid or gas-liquid mixed refrigerant is mixed with the low-pressure liquid refrigerant from the throttling device to suppress the risk of liquid slugging of the compressor by residual gaseous components; The defrosting operation is achieved by the defrosting bypass solenoid valve (6) and the defrosting control valve (8) in combination, and the control process is automatically executed based on a preset logical sequence.

2. The intelligent defrosting control method as described in claim 1, characterized in that, In step S2, the heat exchange components (4) whose defrosting has not been started continue to maintain the heating operation.

3. The intelligent defrosting control method as described in claim 1, characterized in that, Includes the following steps: Before step S2, the frosting status parameters, ambient temperature and corresponding cumulative running time of each heat exchange component (4) are obtained, and a comprehensive judgment is made based on the above parameters. When the preset defrost triggering conditions are met, step S2 is executed to control the corresponding defrost bypass solenoid valve (6) to open and start the defrost process.

4. The intelligent defrosting control method as described in claim 1, characterized in that, In step S4, the temperature of the liquid or gas-liquid mixture refrigerant is monitored, and if it exceeds a set upper limit, the time for it to mix with the working fluid output by the throttling device is delayed to enhance heat exchange stability.

5. The intelligent defrosting control method as described in claim 1, characterized in that, The multiple heat exchange components (4) are finned heat exchangers arranged in a V-shape and sequentially arranged along the airflow direction of the unit.

6. The intelligent defrosting control method as described in claim 1, characterized in that, In the defrosting mode, multiple heat exchange components (4) enter the defrosting state in sequence according to the priority order of reducing thermal interference, with the preferred order being the front component, the diagonal component, the side component, and the rear component.

7. The intelligent defrosting control method as described in claim 1, characterized in that, The heat exchange component (4) receives high-temperature gaseous working fluid from the condenser section of the refrigeration system via an independent bypass path during defrosting.

8. The intelligent defrosting control method as described in claim 1, characterized in that, Each heat exchange component (4) is provided with at least one temperature sensor or frost detection sensor to provide a defrost start signal.

9. The intelligent defrosting control method as described in claim 1, characterized in that, The mixing box (2) is equipped with a turbulence structure to promote the full mixing of the reflux working fluid and the throttling working fluid, thereby reducing the impact of gas-liquid imbalance on system operation.

10. The intelligent defrosting control method as described in claim 1, characterized in that, The defrosting process supports a manual triggering mode, where the defrosting steps can be forcibly executed by the operator in case of automatic control failure or maintenance conditions.

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