Overhead all-in-one machine low-temperature defrosting control method based on efficiency linkage and overhead all-in-one machine

Abstract

The invention provides an overhead all-in-one machine low-temperature defrosting control method based on efficiency linkage, the method is applied to an overhead all-in-one machine, a heat preservation structure is arranged on the surface of a heat exchanger of the overhead all-in-one machine, and the control method comprises the following steps that S1, the environment temperature parameter and the heating efficiency of the overhead all-in-one machine are obtained; s2, when the environment temperature parameter is lower than a low-temperature threshold value, and the deterioration of the heating efficiency relative to a reference value reaches a preset proportion, a defrosting control instruction is triggered; s3, in response to the defrosting control instruction, the overhead all-in-one machine is controlled to execute defrosting operation for a preset duration; and in the defrosting operation, the operation frequency of a compressor of the overhead all-in-one machine is controlled to be matched with the currently used refrigerant type. Defrosting is controlled through linkage control of the environment temperature parameter and the heating efficiency parameter, accurate defrosting is achieved, the energy consumption level is reduced, and the heating efficiency and the user experience feeling are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vehicle air conditioners, and particularly relates to a top-mounted all-in-one machine low-temperature defrosting control method based on efficiency linkage and a top-mounted all-in-one machine. BACKGROUND

[0002] The existing defrosting control of the vehicle top-mounted all-in-one machine mostly adopts a single environmental temperature threshold and a fixed running time, that is, defrosting is started when the ambient temperature is lower than 0℃, and the defrosting time is 8-10 minutes. This mode has defects in a severe cold environment (the ambient temperature is lower than -5℃): first, the frost layer growth rate is not in a linear relationship with the ambient temperature, and frequent invalid defrosting leads to a too long heating interruption time; and the too long invalid defrosting time will cause serious heat loss, reduce the system energy efficiency, and reduce the heating effect. In addition, the heat exchanger and the pipeline are not designed with targeted heat preservation, and the defrosting heat is lost through the bare fins and the pipeline, and it is estimated that the heat loss accounts for more than 20% of the total energy consumption, which aggravates the problem of insufficient heating.

[0003] At the same time, with the diversified development of vehicle air conditioner refrigerants, in addition to mainstream refrigerants such as R32, R410A, R134a, R1234yf and R290, low-GWP mixed refrigerants such as R454B and R452B gradually replace R410A due to environmental protection advantages. The heat exchange coefficients, working pressures and safety of different refrigerants are significantly different, and the traditional defrosting method is mostly designed for a single refrigerant, without fully considering the differences in the heat exchange characteristics of different refrigerants. The defrosting control method for a single refrigerant cannot adapt to the application scene of multiple refrigerants to ensure optimal energy efficiency and safety.

[0004] Therefore, a low-temperature defrosting control method is urgently needed to fundamentally improve the performance, energy efficiency and reliability of the top-mounted all-in-one machine in severe cold working conditions. SUMMARY

[0005] The application aims to overcome the above problems and provides a top-mounted all-in-one machine low-temperature defrosting control method based on efficiency linkage and a top-mounted all-in-one machine, which realizes accurate defrosting and reduces energy consumption by linking the environmental temperature parameter and the heating efficiency.

[0006] Technical scheme: In order to achieve the above purpose, the application provides a top-mounted all-in-one machine low-temperature defrosting control method based on efficiency linkage, which is applied to a top-mounted all-in-one machine, and a heat preservation structure for reducing heat loss during defrosting is arranged on the surface of the heat exchanger of the top-mounted all-in-one machine. The control method comprises the following steps: S1: obtaining the environmental temperature parameter and the heating efficiency of the top-mounted all-in-one machine; S2: triggering a defrosting control instruction when the environmental temperature parameter is lower than a low-temperature threshold and the heating efficiency is deteriorated by a preset proportion compared with a benchmark value; S3: in response to the defrosting control instruction, controlling the top-mounted all-in-one machine to perform a preset time length of defrosting operation; and in the defrosting operation, controlling the operating frequency of the compressor of the top-mounted all-in-one machine to match the current used refrigerant type.

[0007] Further, in the above-mentioned low-temperature defrosting control method of the top-mounted all-in-one machine based on efficiency linkage, the heat preservation structure comprises: a first heat preservation layer wrapped on the non-ventilation surface of the heat exchanger, and a second heat preservation layer wrapped on the outer side of the refrigerant pipeline; the first heat preservation layer and the second heat preservation layer are fixed by winding with aluminum foil tape. The non-ventilation surface includes the base plate and the side plate of the heat exchanger. The first heat preservation layer is arranged on the non-ventilation surface to ensure that the airflow channel between the fins remains unobstructed, and the first heat preservation layer is intended to block the heat exchange between the outer surface of the heat exchanger and the indoor air. The second heat preservation layer is arranged on the outer side of the refrigerant pipeline to reduce the heat loss of the pipeline. The first heat preservation layer and the second heat preservation layer are fixed by winding with aluminum foil tape and the heat exchanger fins and the pipeline to ensure that there is no gap exposed.

[0008] Further, in the above-mentioned low-temperature defrosting control method of the top-mounted all-in-one machine based on efficiency linkage, the material of the first heat preservation layer and the second heat preservation layer is flame-retardant rubber-plastic insulation cotton; the thickness of the first heat preservation layer is 10-20mm, and the thickness of the second heat preservation layer is 5-15mm. The flame-retardant rubber-plastic insulation cotton has low thermal conductivity (≤0.035 W / (m•K)) and high flame-retardant level (≥V0 level).

[0009] Further, in the above-mentioned low-temperature defrosting control method of the top-mounted all-in-one machine based on efficiency linkage, the heating efficiency is the heating efficiency η, which is calculated by the actual heating capacity of the top-mounted all-in-one machine / input power. The actual heating capacity is calculated by the difference between the outlet air temperature and the inlet air temperature, and the input power is the compressor power consumption.

[0010] Further, in the above-mentioned low-temperature defrosting control method of the top-mounted all-in-one machine based on efficiency linkage, the preset proportion of the deterioration of the heating efficiency compared to the reference value is that the heating efficiency η decreases by 30% or more than 30% compared to the rated value.

[0011] Further, in the above-mentioned low-temperature defrosting control method of the top-mounted all-in-one machine based on efficiency linkage, the low-temperature threshold is -5℃, and the preset time length is 4-5 minutes.

[0012] Further, in the above-mentioned low-temperature defrosting control method of the top-mounted all-in-one machine based on efficiency linkage, the refrigerant is miscible with POE refrigeration oil, and is selected from at least one of R32, R410A, R134a, R1234yf, R290, R454B and R452B.

[0013] Further, in the above-mentioned low-temperature defrosting control method for the top-mounted all-in-one machine based on efficiency linkage, when the refrigerant is R454B or R452B, the operating frequency of the compressor is 65%-75% of the rated frequency of the compressor. For the new refrigerant such as R454B or R452B with a higher heat exchange coefficient, the power of the compressor is optimized to balance the defrosting speed and energy consumption.

[0014] Further, in the above-mentioned low-temperature defrosting control method for the top-mounted all-in-one machine based on efficiency linkage, when the refrigerant is R454B or R452B, the operating frequency of the compressor is 65%-75% of the rated frequency of the compressor. For the new refrigerant such as R454B or R452B with a higher heat exchange coefficient, the power of the compressor is optimized to balance the defrosting speed and energy consumption.

[0015] A top-mounted all-in-one machine, characterized in comprising a controller, a compressor, a heat exchanger, and a fan; the heat exchanger is provided with a heat preservation structure on the surface; the controller is configured to execute the above-mentioned low-temperature defrosting control method for the top-mounted all-in-one machine based on efficiency linkage.

[0016] The above-mentioned technical solution can achieve the following beneficial effects: ①The low-temperature defrosting control method for the top-mounted all-in-one machine based on efficiency linkage and the top-mounted all-in-one machine can realize accurate defrosting, reduce energy consumption, and improve user experience by acquiring the double parameters of environmental temperature and heating efficiency, starting defrosting when the environment is cold enough and frost has formed, and avoiding invalid defrosting based on a single parameter in a low-temperature environment.

[0017] ②The heat exchanger surface (non-ventilation surface) is provided with a heat preservation structure to ensure the smoothness of the fin air duct and reduce heat loss during defrosting, thereby improving the overall energy efficiency.

[0018] ③The frequency is optimized for new environmentally friendly refrigerants to improve efficiency and further improve energy efficiency and user experience.

[0019] ④The software space algorithm and thermal insulation material are used to reduce costs, facilitate deployment and promotion, and have significant market competitiveness. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The logic flow chart of the low-temperature defrosting control method for the top-mounted all-in-one machine based on efficiency linkage is shown in the figure. Figure 2 The table of refrigerant physical parameters and compressor frequency adjustment under defrosting conditions is shown in the figure. DETAILED DESCRIPTION EMBODIMENT

[0021] In order to make the objects, technical solutions and advantages of the present application clearer, the following further describes the present application in combination with the principles and preferred embodiments of the present application. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the protection scope of the present application.

[0022] As shown in Figure 1 An efficiency linkage-based low-temperature defrosting control method for a top-mounted all-in-one machine, applied to a top-mounted all-in-one machine, wherein a heat preservation structure for reducing heat loss during defrosting is arranged on the surface of a heat exchanger of the top-mounted all-in-one machine, and the control method comprises the following steps: S1: obtaining an ambient temperature parameter and a heating efficiency of the top-mounted all-in-one machine; S2: triggering a defrosting control instruction when the ambient temperature parameter is lower than a low-temperature threshold value and the heating efficiency deteriorates by a preset proportion compared with a benchmark value; S3: in response to the defrosting control instruction, controlling the top-mounted all-in-one machine to perform a defrosting operation for a preset time length, and in the defrosting operation, controlling the operating frequency of a compressor of the top-mounted all-in-one machine to match the current type of refrigerant.

[0023] The present application is applied to a programmable top-mounted air conditioner all-in-one machine for vehicles, and through software upgrading and structure optimization of the existing equipment, the present application realizes double-parameter triggering of ambient temperature and heating efficiency, avoids invalid defrosting, reduces heating interruption time, and improves overall efficiency and user experience.

[0024] As a further preferred embodiment of the present application, the heat preservation structure comprises: a first heat preservation layer wrapped on the non-ventilation surface of the heat exchanger, and a second heat preservation layer wrapped on the outer side of the refrigerant pipeline; the first heat preservation layer and the second heat preservation layer are fixed by winding with aluminum foil tape. The first heat preservation layer is wrapped on the non-ventilation surface of the indoor side heat exchanger, and ensures that the airflow channel between the fins remains unobstructed, without affecting the original air volume and heat exchange performance. The second heat preservation layer is arranged on the outer side of the refrigerant pipeline to reduce heat loss of the pipeline. The first heat preservation layer and the second heat preservation layer are fixed by winding with the heat exchanger fins and the pipeline, and the winding overlap rate is greater than or equal to 15%, and the second heat preservation layer on the outer side of the refrigerant pipeline is fixed with a tie, so as to ensure that there is no gap exposed.

[0025] As a further preferred embodiment of the present application, the materials of the first heat preservation layer and the second heat preservation layer are flame-retardant rubber-plastic insulation cotton; the thickness of the first heat preservation layer is 10-20mm, and the thickness of the second heat preservation layer is 5-15mm. The flame-retardant rubber-plastic insulation cotton has low thermal conductivity (≤0.035 W / (m•K)) and high flame-retardant grade (≥V0 grade).

[0026] As a further preferred embodiment, the heating efficiency is η, which is calculated by dividing the actual heating capacity of the top-mounted integrated unit by the input power. The actual heating capacity is calculated by the difference between the outlet air temperature and the inlet air temperature, and the input power is the compressor power consumption.

[0027] As a further preferred embodiment, the heating efficiency deteriorates to a preset percentage relative to the benchmark value when the heating efficiency η decreases by 30% or more compared to its rated value. The benchmark value is the rated heating efficiency value.

[0028] As a further preferred embodiment, the low temperature threshold is -5°C, and the preset duration is 4-5 minutes.

[0029] As a further preferred embodiment, the refrigerant is a refrigerant miscible with POE refrigeration oil, and is selected from at least one of R32, R410A, R134a, R1234yf, R290, R454B and R452B.

[0030] As a further preferred embodiment, when the refrigerant is R454B or R452B, the compressor's operating frequency is 65%-75% of the compressor's rated frequency. For new refrigerants like R454B or R452B, which have a high heat transfer coefficient, the compressor power is optimized to achieve a balance between defrosting speed and energy consumption.

[0031] As a further preferred embodiment, when the refrigerant is R290, before step S3, the refrigerant leakage concentration in the refrigeration circuit is detected; if the leakage concentration is lower than the safety threshold, then S3 is executed; otherwise, the defrosting operation is prohibited and an alarm is triggered.

[0032] A top-mounted integrated air conditioner, characterized in that it comprises: a controller, a compressor, a heat exchanger, and a fan; the surface of the heat exchanger is provided with a heat insulation structure; the controller is configured to execute the above-mentioned efficiency-linked low-temperature defrosting control method for the top-mounted integrated air conditioner. The controller is programmed with the control program of this invention, and the control program sets the following parameters: low-temperature threshold of -5℃; rated heating efficiency η=3.2; heating efficiency reduction trigger ratio of 30%; defrosting time of 4.5 minutes; if flammable refrigerant R290 is used, a leakage safety threshold of 1000ppm is set. The controller is input with the refrigerant type and its corresponding recommended defrosting frequency coefficient (e.g., R32 / R410A / R134a / R1234yf corresponds to 60%-70%; R454B / R452B corresponds to 65%-70%). When the ambient temperature is <-5℃ and η≤2.24 (reduction reaches or exceeds 30%), defrosting is triggered, and the defrosting frequency reduction parameters are automatically matched according to the refrigerant type.

[0033] The system operation process is as follows: After the rooftop unit starts, the controller collects real-time data from the ambient temperature sensor and the unit's operating parameters. When the ambient temperature is detected to be below -5℃, the controller begins to continuously calculate the heating efficiency η. This is achieved by using temperature sensors installed at the evaporator inlet and outlet to obtain the inlet and outlet air temperatures in real time, combined with the fan airflow, and calculating the actual heating capacity (in W) using the formula: fan airflow × (outlet air temperature - inlet air temperature). Simultaneously, the controller collects the real-time input power P of the compressor (in W), thus obtaining η = actual heating capacity / P. The controller compares the calculated η with the rated heating efficiency of 3.2. When η ≤ 2.24 (i.e., a decrease of 30% or more from the rated value), the defrosting trigger condition is met. At this point, the controller first identifies the type of refrigerant currently used by the rooftop unit. If the refrigerant is R454B or R452B, the controller will adjust the compressor's operating frequency to 65%-75% of its rated frequency. For example, if the rated frequency is 60Hz, it will be adjusted to 39Hz-45Hz. If the refrigerant is R290, the refrigerant leakage concentration detection module must be activated before defrosting. A concentration sensor located at a key node in the refrigeration circuit will detect the R290 leakage concentration. If the concentration is below the safety threshold (1000ppm), defrosting will be initiated. If the concentration exceeds the limit, defrosting will be immediately prohibited, and an alarm signal will be sent. After the defrosting conditions are met, a 4.5-minute defrosting operation will begin. After the defrosting timer ends, the top-mounted unit will re-enter heating mode.

[0034] The above embodiments are exemplary and are intended to illustrate the technical concept and features of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for controlling low-temperature defrosting of a top-mounted integrated air conditioner based on efficiency linkage, applied to a top-mounted integrated air conditioner, characterized in that: The heat exchanger surface of the top-mounted integrated unit is provided with an insulation structure to reduce heat loss during defrosting. The control method includes the following steps: S1: Obtain the ambient temperature parameters and heating efficiency of the top-mounted integrated unit; S2: When the ambient temperature parameter is lower than the low temperature threshold and the heating efficiency deteriorates to a preset ratio compared to the baseline value, a defrosting control command is triggered. S3: In response to the defrosting control command, control the top-mounted integrated unit to perform a defrosting operation of a preset duration; and during the defrosting operation, control the operating frequency of the compressor of the top-mounted integrated unit to match the type of refrigerant currently used.

2. The method for controlling low-temperature defrosting of a top-mounted integrated air conditioner based on efficiency linkage according to claim 1, characterized in that: The insulation structure includes: a first insulation layer covering the non-ventilated surface of the heat exchanger, and a second insulation layer covering the outside of the refrigerant pipeline; the first insulation layer and the second insulation layer are fixed by wrapping with aluminum foil tape.

3. The method for controlling low-temperature defrosting of a top-mounted integrated air conditioner based on efficiency linkage according to claim 2, characterized in that: The first insulation layer and the second insulation layer are made of flame-retardant rubber and plastic insulation cotton; the thickness of the first insulation layer is 10-20mm, and the thickness of the second insulation layer is 5-15mm.

4. The method for controlling low-temperature defrosting of a top-mounted integrated air conditioner based on efficiency linkage according to claim 1, characterized in that: The heating efficiency is η, which is the ratio of the actual heating capacity of the top-mounted integrated unit to the input power.

5. The method for controlling low-temperature defrosting of a top-mounted integrated air conditioner based on efficiency linkage according to claim 1, characterized in that: The heating efficiency deteriorates to a preset percentage relative to the benchmark value when the heating efficiency η decreases by 30% or more compared to its rated value.

6. The method for controlling low-temperature defrosting of a top-mounted integrated air conditioner based on efficiency linkage according to claim 1, characterized in that: The low temperature threshold is -5℃, and the preset duration is 4-5 minutes.

7. The method for controlling low-temperature defrosting of a top-mounted integrated air conditioner based on efficiency linkage according to claim 1, characterized in that: The refrigerant is a refrigerant miscible with POE refrigeration oil, and is selected from at least one of R32, R410A, R134a, R1234yf, R290, R454B and R452B.

8. The method for controlling low-temperature defrosting of a top-mounted integrated air conditioner based on efficiency linkage according to claim 7, characterized in that: When the refrigerant is R454B or R452B, the compressor's operating frequency is 65%-75% of the compressor's rated frequency.

9. The method for controlling low-temperature defrosting of a top-mounted integrated air conditioner based on efficiency linkage according to claim 7, characterized in that: When the refrigerant is R290, before step S3, the refrigerant leakage concentration in the refrigeration circuit is detected; if the leakage concentration is lower than the safety threshold, then S3 is executed; otherwise, the defrosting operation is prohibited and an alarm is triggered.

10. A top-mounted integrated air conditioner, characterized in that: include: The system includes a controller, a compressor, a heat exchanger, and a fan; the heat exchanger surface is provided with a heat insulation structure; the controller is configured to execute the low-temperature defrosting control method for a top-mounted integrated unit based on efficiency linkage as described in any one of claims 1 to 9.

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