Micro-channel heat exchanger air conditioner and its restart heating control method

Abstract

A kind of micro-channel heat exchanger air conditioner and its restart heating control method, the air conditioner includes indoor heat exchanger, outdoor heat exchanger, compressor, four-way reversing valve, electronic expansion valve and electric heater;Micro-channel heat exchanger air conditioner in the restart heating stage there is a lower evaporation pressure phenomenon, resulting in the lower temperature of micro-channel heat exchanger lower part, frost rate is faster, the performance of the entire low-temperature heating cycle is influenced.The present application proposes a kind of micro-channel heat exchanger air conditioner restart heating control method, using electric heating, compressor stage frequency increasing, control valve opening degree mode, eliminate the lower evaporation pressure phenomenon of air conditioner restart heating stage, delay the frost of micro-channel heat exchanger lower part, optimize the performance of the entire low-temperature heating cycle of air conditioner.

Description

Technical Field

[0001] This invention relates to the field of microchannel heat exchanger air conditioner technology, specifically to a microchannel heat exchanger air conditioner and its restart heating control method. Background Technology

[0002] Compared with traditional finned tube heat exchangers, microchannel heat exchangers have advantages such as compact structure, small size, light weight, high heat exchange efficiency, low refrigerant charge, and low manufacturing cost. They have been widely used in refrigeration equipment, especially for the promotion of hydrocarbon flammable refrigerants in household air conditioners. Microchannel heat exchangers can reduce the charge and play a very important role in the application of environmentally friendly and efficient refrigerants.

[0003] However, after replacing the original finned tube heat exchanger with a microchannel heat exchanger, it was found that the microchannel heat exchanger frosted faster, directly affecting the overall performance of the unit. Especially during the restart heating phase of the microchannel heat exchanger air conditioner, there is a period of very low pressure in the microchannel heat exchanger, leading to rapid frosting at the bottom and a rapid decline in overall performance. Theoretical analysis revealed that the low pressure in the microchannel heat exchanger is due to gravity causing liquid refrigerant to accumulate in the lower liquid collector. This liquid refrigerant can only be removed through flash evaporation, and the refrigerant is not replenished to the microchannel heat exchanger in a timely manner. This results in excessive refrigerant extraction by the microchannel heat exchanger, leading to a very low pressure period during the restart heating phase of the microchannel air conditioner. Summary of the Invention

[0004] To address the problems existing in the prior art, eliminate the low-pressure phenomenon during the restart heating phase of the microchannel heat exchanger air conditioner, and delay frost formation during the restart heating phase, this invention proposes a microchannel heat exchanger air conditioner and its restart heating control method to improve the overall performance of the unit during low-temperature heating.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0006] A microchannel heat exchanger air conditioner includes a compressor 01, a four-way reversing valve 02, an indoor heat exchanger 03, a throttling valve 04, a first liquid collection pipe 05, an electric heater 06, fins 07, a flat tube 08, a second liquid collection pipe 09, a pressure sensor P1, and a control module C1. The discharge port of the compressor 01 is connected to the first port 21 of the four-way reversing valve, the suction port of the compressor 01 is connected to the third port 23 of the four-way reversing valve, the fourth port 24 of the four-way reversing valve is connected to the left end of the second liquid collection pipe 09, the second port 22 of the four-way reversing valve is connected to the indoor heat exchanger 03, the indoor heat exchanger 03 is connected to the throttling valve 04, and the throttling valve 04 is connected to the first liquid collection pipe 05. A first liquid collecting pipe 05 and a second liquid collecting pipe 09 are connected together by multiple flat tubes 08. Fins 07 are installed between adjacent flat tubes. An electric heater 06 is arranged inside the first liquid collecting pipe 05. A pressure sensor P1 is arranged on the pipe entering the first liquid collecting pipe 05. The first liquid collecting pipe 05, fins 07, flat tubes 08 and the second liquid collecting pipe 09 form a microchannel heat exchanger. The control module C1 is connected to the compressor 01, the throttle valve 04, the pressure sensor P1 and the electric heater 06. It is used to collect the signal from the pressure sensor P1 and control the frequency of the compressor 01, the opening degree of the throttle valve 04 and the heating power of the electric heater 06.

[0007] The electric heater 06 is arranged inside the first liquid collection pipe 06 and is used to heat the microchannel heat exchanger during the restart heating stage.

[0008] A control method for the restart heating phase of a microchannel heat exchanger air conditioner is as follows: Pressure sensor P1 is used to detect the pressure at the inlet of the microchannel heat exchanger. Control module C1 collects the signal from pressure sensor P1 and controls the heating power and on / off state of electric heater 05, the frequency of compressor 01, and the opening degree of electronic expansion valve 04; the specific control is as follows:

[0009] Step 1: Set the maximum operating frequency of compressor 01 to f0. After the control module C1 detects the signal of compressor reheating, it turns on electric heater 05, the heating power W is full power, and the throttle valve 04 is fully open. The frequency of compressor 01 is set to f1.

[0010] Step 2: When the pressure stabilizes during operation, and the pressure change is within the range of ΔP within the time period Δt, compare the magnitudes of f0 and f1, and proceed to step 3 or step 4; when the pressure is unstable, the control module C1 detects the pressure change every preset time and continues to make judgments.

[0011] Step 3: When |f0-f1|>Δf, the throttle valve 04 is fully open, the heating power of the electric heater 05 is reduced by ΔW, and the operating frequency of the compressor 01 is set to f1=f1+Δf. Then return to step 2 for judgment.

[0012] Step 4: When |f0-f1|<Δf, set the frequency of compressor 01 to the maximum operating frequency f0, the opening of throttle valve 04 is controlled by the exhaust temperature of compressor 01, and turn off electric heater 05.

[0013] The value ranges of parameters W, ΔW, ΔP, f1, and f2 are shown in the table below:

[0014] Range of values 500-1000w 100-400w 0.1-0.2MP parameter Δf <![CDATA[f0]]> <![CDATA[f1]]> Range of values 20-30Hz 70-100HZ 20-40HZ

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. This invention proposes a microchannel heat exchanger air conditioner and its restart heating stage control method, which can eliminate the phenomenon of low evaporation pressure during the restart heating stage of the microchannel heat exchanger air conditioner, delay the frosting at the bottom of the microchannel heat exchanger during this stage, and improve the performance of the entire low-temperature heating cycle.

[0017] 2. This invention proposes a feasible and effective control method that uses the inlet pressure of the microchannel heat exchanger as the control signal to simultaneously control the compressor's 01-stage frequency increase, the opening degree of the electronic expansion valve 04, and the power of the electric heater 06, thereby enabling precise control of the microchannel heat exchanger's restart heating stage. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a microchannel heat exchanger air conditioner restart heating stage control method according to the present invention.

[0019] Figure 2 This is a control logic diagram of a microchannel heat exchanger air conditioner restart heating stage control method according to the present invention. Detailed Implementation

[0020] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] like Figure 1As shown, the microchannel heat exchanger air conditioner of the present invention has the following connection method: A microchannel heat exchanger air conditioner includes a compressor 01, a four-way reversing valve 02, an indoor heat exchanger 03, a throttling valve 04, a first liquid collection pipe 05, an electric heater 06, fins 07, a flat tube 08, a second liquid collection pipe 09, a pressure sensor P1, and a control module C1. The exhaust port of the compressor 01 is connected to the first port 21 of the four-way reversing valve, the suction port of the compressor 01 is connected to the third port 23 of the four-way reversing valve, the fourth port 24 of the four-way reversing valve is connected to the left end of the second liquid collection pipe 09, the second port 22 of the four-way reversing valve is connected to the indoor heat exchanger 03, the indoor heat exchanger 03 is connected to the throttling valve 04, and the throttling valve 04 is connected to... A microchannel heat exchanger is formed by connecting the first liquid collecting pipe 05, multiple flat tubes 08 arranged in and connecting the first liquid collecting pipe 05 and the second liquid collecting pipe 09, fins 07 installed between adjacent flat tubes, an electric heater 06 arranged inside the first liquid collecting pipe 05, and a pressure sensor P1 arranged on the pipe entering the first liquid collecting pipe 05; wherein the first liquid collecting pipe 05, fins 07, flat tubes 08 and the second liquid collecting pipe 09 form a microchannel heat exchanger; the control module C1 is connected to the compressor 01, the throttle valve 04, the pressure sensor P1 and the electric heater 06, and is used to collect the signal of the pressure sensor P1 and control the frequency of the compressor 01, the opening degree of the throttle valve 04 and the heating power of the electric heater 06.

[0022] The electric heater 06 is arranged inside the first liquid collection pipe 06 and is used to heat the microchannel heat exchanger during the restart heating stage.

[0023] like Figure 2 As shown, a control method for the restart heating stage of a microchannel heat exchanger air conditioner is as follows: Pressure sensor P1 is used to detect the pressure at the inlet of the microchannel heat exchanger. Control module C1 collects the signal from pressure sensor P1 and controls the heating power and on / off state of electric heater 05, the frequency of compressor 01, and the opening degree of electronic expansion valve 04. The specific control is as follows:

[0024] Step 1: Set the maximum operating frequency of compressor 01 to f0. After the control module C1 detects the signal of compressor reheating, it turns on electric heater 05, the heating power W is full power, and the throttle valve 04 is fully open. The frequency of compressor 01 is set to f1.

[0025] Step 2: When the pressure stabilizes during operation, and the pressure change is within the range of ΔP within the time interval Δt, compare the magnitudes of f0 and f1, and proceed to step 3 or step 4; when the pressure is unstable, the control module C1 detects the pressure change every 2 seconds and continues to make judgments.

[0026] Step 3: When |f0-f1|>Δf, the throttle valve 04 is fully open, the heating power of the electric heater 05 is reduced by ΔW, and the operating frequency of the compressor 01 is set to f1=f1+Δf. Then return to step 2 for judgment.

[0027] Step 4: When |f0-f1|<Δf, set the frequency of compressor 01 to the maximum operating frequency f0, the opening of throttle valve 04 is controlled by the exhaust temperature of compressor 01, and turn off electric heater 05.

[0028] The value ranges of parameters W, ΔW, ΔP, f1, and f2 are shown in the table below.

[0029] Range of values 500-1000w 100-400w 0.1-0.2MP parameter Δf <![CDATA[f0]]> <![CDATA[f1]]> Range of values 20-30Hz 70-100HZ 20-40HZ

[0030] The working method of the microchannel heat exchanger air conditioner of the present invention is as follows: Figure 1 As shown, the compressor (01) compresses the refrigerant to a high temperature and high pressure state, and then enters the four-way reversing valve (02). The refrigerant coming out of the four-way reversing valve (02) enters the indoor heat exchanger (03) for condensation and heat exchange, providing a heat source for the room. The liquid refrigerant coming out of the indoor heat exchanger (03) enters the throttling valve (04) to be throttled to a low temperature and low pressure state, and then enters the first liquid collector (05). After passing through the first liquid collector (05), the refrigerant enters the flat tube (08) for evaporation and heat exchange, and then enters the second liquid collector (09). The refrigerant coming out of the second liquid collector (09) passes through the four-way reversing valve (02) and then enters the compressor (01) for compression.

Claims

1. A restart heating control method for a microchannel heat exchanger air conditioner, the air conditioner comprising a compressor (01), a four-way reversing valve (02), an indoor heat exchanger (03), a throttle valve (04), a first liquid collection pipe (05), an electric heater (06), fins (07), a flat tube (08), a second liquid collection pipe (09), a pressure sensor (P1), and a control module (C1), wherein the exhaust port of the compressor (01) is connected to the first port (21) of the four-way reversing valve, the suction port of the compressor (01) is connected to the third port (23) of the four-way reversing valve, the fourth port (24) of the four-way reversing valve is connected to the left end of the second liquid collection pipe (09), the second port (22) of the four-way reversing valve is connected to the indoor heat exchanger (03), the indoor heat exchanger (03) is connected to the throttle valve (04), and the throttle valve (04) is connected to the first liquid collection pipe (05). 5) Connected, multiple flat tubes (08) are set in the first liquid collection pipe (05) and the second liquid collection pipe (09) and connected to the first liquid collection pipe (05) and the second liquid collection pipe (09), fins (07) are installed between adjacent flat tubes, electric heater (06) is arranged inside the first liquid collection pipe (05), and pressure sensor (P1) is arranged on the pipe entering the first liquid collection pipe (05); wherein the first liquid collection pipe (05), fins (07), flat tubes (08) and the second liquid collection pipe (09) form a microchannel heat exchanger; the control module (C1) is connected to the compressor (01), throttle valve (04), pressure sensor (P1) and electric heater (06) to collect the signal of pressure sensor (P1) and control the frequency of compressor (01), the opening degree of throttle valve (04) and the heating power of electric heater (06); Its features are: The restart heating control method for the air conditioner uses a pressure sensor (P1) to detect the pressure at the inlet of the microchannel heat exchanger. The control module (C1) collects the signal from the pressure sensor (P1) and controls the heating power and on / off state of the electric heater (06), the frequency of the compressor (01), and the opening degree of the electronic expansion valve (04). The specific control is as follows: Step 1: Set the maximum operating frequency of the compressor (01) to [value missing]. After the control module (C1) detects the compressor reheating signal, it turns on the electric heater (06) with a heating power of To achieve full power, with the throttle valve (04) fully open and the compressor (01) frequency set to [value missing], [details missing]. ; Step 2: During the operation, Pressure changes over a period of time Within the range, at this time comparison and The size of the pressure determines the next step, proceeding to step 3 or 4; when the pressure is unstable, the control module (C1) detects the pressure change every preset time and continues to make a determination. Step 3: When At that time, the throttle valve (04) is fully open, and the heating power of the electric heater (06) decreases. And set the operating frequency of the compressor (01) to Then return to step 2 for judgment; Step 4: When At that time, set the frequency of compressor (01) to the maximum operating frequency. The opening degree of the throttle valve (04) is controlled by the exhaust temperature of the compressor (01), and the electric heater (06) is turned off. Among them, the parameters are set. , , , , The range of values ​​for is shown in the table below: 。 2. The restart heating control method for a microchannel heat exchanger air conditioner according to claim 1, characterized in that: An electric heater (06) is arranged inside the first liquid collection pipe (05) for heating the microchannel heat exchanger during the restart heating phase.

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