Multi-connected direct expansion indoor unit system and control method thereof

Abstract

The application discloses a multi-connected direct expansion indoor unit system and a control method thereof, which comprises an outdoor unit, a main indoor unit and multiple reference indoor units; the main indoor unit is connected with the outdoor unit through a main liquid-side branch pipe, a main gas-side branch pipe, a main liquid-side connecting pipe and a main gas-side connecting pipe; the secondary indoor unit is connected with the outdoor unit through a secondary liquid-side branch pipe, a secondary gas-side branch pipe, a secondary liquid-side connecting pipe and a secondary gas-side connecting pipe; a first throttling electronic expansion valve is arranged on the main liquid-side branch pipe, and a second throttling electronic expansion valve is arranged on the secondary liquid-side branch pipe; the main indoor unit for cooling or heating a comfortable space and the reference indoor unit for cooling or heating a process space are combined into one refrigeration system, and the refrigeration or demand of each space is controlled according to the production requirement.

Description

TECHNICAL FIELD

[0001] The present application relates to refrigeration and air conditioning related technical field, specifically to a kind of multi-connected direct expansion indoor unit system and control method. BACKGROUND

[0002] Prior art for comfort air conditioning Multi-connected unit technology is very mature, for process air conditioning Direct expansion unit technology is also mature, but process air conditioning Direct expansion unit basically adopts one-to-one mode, cannot realize process air conditioning and comfort air conditioning coexist in one system.

[0003] In practical application, often encounter a factory or workshop, process air conditioning is needed;But factory office or workshop office needs comfort air conditioning demand.For this application scenario, conventional Multi-connected unit or Direct expansion unit cannot meet. SUMMARY

[0004] To solve the defects that conventional Multi-connected unit or Direct expansion unit cannot realize process air conditioning and comfort air conditioning coexist in one system in prior art, the present application provides a kind of multi-connected direct expansion indoor unit system and control method.

[0005] To solve the above technical problems, the present application provides the following technical solutions:

[0006] The present application provides a kind of multi-connected direct expansion indoor unit system, comprising outdoor unit, main indoor unit and multiple reference indoor units;The main indoor unit is connected with outdoor unit through main connecting pipe group, and the secondary indoor unit is connected with outdoor unit through secondary connecting pipe group;The main indoor unit is used for cooling or heating comfort space;The reference indoor unit is used for cooling or heating process space, and the comfort space is provided with first temperature sensor for detecting the temperature in space, and the process space is provided with second temperature sensor for detecting the temperature in space;The priority of main indoor unit is greater than the priority of reference indoor unit.

[0007] As a preferred technical solution of the present application, the main connecting pipe group is connected by main liquid side branch pipe, main gas side branch pipe, main liquid side connecting pipe and main gas side connecting pipe;First throttling electronic expansion valve is arranged on the main liquid side branch pipe.

[0008] As a preferred technical solution of the present application, the secondary connecting pipe group is connected by secondary liquid side branch pipe, secondary gas side branch pipe, secondary liquid side connecting pipe and secondary gas side connecting pipe;Second throttling electronic expansion valve is arranged on the secondary liquid side branch pipe.

[0009] As a preferred technical solution of the present application, the comfort space is provided with first humidity sensor for detecting the humidity in space.

[0010] As a preferred technical solution of the present invention, a second humidity sensor for detecting the humidity in the space is provided in the process space.

[0011] As a preferred technical solution of the present invention, a control method for a multi-connected direct expansion indoor unit system is characterized by including the following steps:

[0012] Step 1: First, define the main indoor unit and the reference indoor unit;

[0013] Step 2: Use the first temperature sensor and the first humidity sensor to detect the temperature Tm and humidity RHm of the indoor space of the comfort space corresponding to the main indoor unit. Then compare the detected temperature Tm with the set temperature Tset, and compare the detected humidity RHm with the set humidity RHset;

[0014] Step 3: Control the opening degrees of the first throttle electronic expansion valve and the second throttle electronic expansion valve according to the comparison results, and adjust the refrigerant flow rates passing through the main indoor unit and the reference indoor unit; thereby adjusting the working mode of the main indoor unit;

[0015] Step 4: When there is a conflict between the working mode of the main indoor unit and the working mode of the reference indoor unit, prioritize ensuring the working mode of the main indoor unit.

[0016] As a preferred technical solution of the present invention, the specific method of controlling the opening degree of the first throttle electronic expansion valve according to the comparison results in step 3, adjusting the refrigerant flow rates passing through the main indoor unit and the reference indoor unit; and adjusting the working mode of the main indoor unit is as follows. Under the refrigeration condition,

[0017] When Tm > Tset + △T1 or RHm > RHset + △RH1, the first throttle electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is opened △S1 steps, and the second throttle electronic expansion valve of the reference indoor unit is closed △S2 steps. △S1 is default 36 steps, adjustable from 12 to 64 steps; △S2 is default 36 steps, adjustable from 12 to 64 steps; △T1 is default 5°C, adjustable from 3 to 6°C; △RH1 is default 8%RH, adjustable from 6 to 10%RH;

[0018] When Tset + △T2 < Tm ≤ Tset + △T1 or RHset + △RH2 < RHm ≤ RHset + △RH1, the first throttle electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is opened △S3 steps, and the second throttle electronic expansion valve of its reference indoor unit is closed △S4 steps. △S3 is default 18 steps, adjustable from 4 to 48 steps; △S4 is default 18 steps, adjustable from 4 to 48 steps; △T2 is default 2°C, adjustable from 1 to 3°C; △RH1 is default 5%RH, adjustable from 3 to 6%RH;

[0019] When Tset - △T2 < Tm ≤ Tset + △T2 or RHset - △RH2 < RHm ≤ RHset + △RH2, the opening degree of the first throttling electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect remains unchanged; the second throttling electronic expansion valve of its reference indoor unit is adjusted according to their respective requirements.

[0020] When Tset - △T1 < Tm ≤ Tset - △T2 or RHset - △RH1 < RHm ≤ RHset - △RH2, the first throttling electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is closed by △S3 steps, and the second throttling electronic expansion valves of other reference indoor units are opened by △S4 steps;

[0021] When Tm ≤ Tset - △T1 or RHm ≤ RHset - △RH1. The first throttling electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is closed by △S1 steps, and the second throttling electronic expansion valve of the reference indoor unit is opened by △S2 steps.

[0022] As a preferred technical solution of the present invention, under the heating condition,

[0023] When Tm > Tset + △T1, the first throttling electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is closed by △S1 steps, and the second throttling electronic expansion valves of other reference indoor units are opened by △S2 steps;

[0024] When Tset + △T2 < Tm ≤ Tset + △T1. The first throttling electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is closed by △S3 steps, and the second throttling electronic expansion valves of other reference indoor units are opened by △S4 steps;

[0025] When Tset - △T2 < Tm ≤ Tset + △T2, the opening degree of the first throttling electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect remains unchanged; the second throttling electronic expansion valves of other reference indoor units are adjusted according to their respective requirements;

[0026] When Tset - △T1 < Tm ≤ Tset - △T2, the first throttling electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is opened by △S3 steps, and the second throttling electronic expansion valves of other reference indoor units are closed by △S4 steps;

[0027] When Tm ≤ Tset - △T1, the first throttling electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is opened by △S1 steps, and the second throttling electronic expansion valves of other reference indoor units are closed by △S2 steps.

[0028] As a preferred technical solution of the present invention, the specific operation of step 4 is

[0029] When priority is given to ensuring the main indoor unit is in heating mode and other reference indoor units are in cooling mode, the air conditioning system operates in heating mode. The main indoor unit that needs to ensure the effect is controlled by the opening of the first throttling electronic expansion valve according to the superheat; the second throttling electronic expansion valve of other reference indoor units is closed and the fan operates normally.

[0030] When priority is given to ensuring the main indoor unit is in cooling mode and other reference indoor units are in heating mode, the air conditioning system operates in cooling mode. The main indoor unit that needs to ensure the effect controls the opening of the first throttling electronic expansion valve according to the superheat; the second electronic expansion valve of other reference indoor units is closed and the fan stops running.

[0031] The beneficial effects of this invention are:

[0032] This multi-split direct expansion indoor unit system combines a main indoor unit that cools or heats comfort spaces and a reference indoor unit that cools or heats process spaces into a single refrigeration system. Furthermore, it controls the cooling or demand of each space according to production needs. By setting specific control methods to comprehensively adjust the refrigerant flow through the main indoor unit and the reference indoor unit, the air conditioning effect of the main indoor unit is guaranteed. The control method provided by this invention is simple and easy to implement, and can take into account the air conditioning effects of both the main indoor unit and the reference indoor unit. Attached Figure Description

[0033] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0034] In the attached diagram:

[0035] Figure 1 This is a schematic diagram of the structure of a multi-unit direct expansion internal machine system according to the present invention.

[0036] In the diagram: 1. Outdoor unit; 2. Main indoor unit; 201. Main liquid side branch pipe; 202. Main gas side branch pipe; 203. Main liquid side connecting pipe; 204. Main gas side connecting pipe; 205. First throttling electronic expansion valve; 3. Reference indoor unit; 301. Secondary liquid side branch pipe; 302. Secondary gas side branch pipe; 303. Secondary liquid side connecting pipe; 304. Secondary gas side connecting pipe; 305. Second throttling electronic expansion valve; 4. First temperature sensor; 5. Second temperature sensor; 6. Comfort space; 7. Process space; 8. First humidity sensor; 9. Second humidity sensor. Detailed Implementation

[0037] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0038] Example: Figure 1 As shown, the present invention discloses a multi-split direct expansion indoor unit system, comprising an outdoor unit 1, a main indoor unit 2, and multiple reference indoor units 3; the main indoor unit 2 is connected to the outdoor unit 1 via a main liquid-side branch pipe 201, a main gas-side branch pipe 202, a main liquid-side connecting pipe 203, and a main gas-side connecting pipe 204; the secondary indoor units 3 are connected to the outdoor unit 1 via a secondary liquid-side branch pipe 301, a secondary gas-side branch pipe 302, a secondary liquid-side connecting pipe 303, and a secondary gas-side connecting pipe 304; the main indoor unit 2 is used to cool or heat the comfort space 6; the reference indoor units 3 are used to cool or heat the process space 7, and the comfort space 6 is equipped with a first temperature sensor 4 for detecting the temperature within the space, and the process space 7 is equipped with a second temperature sensor 5 for detecting the temperature within the space; the main liquid-side branch pipe 201 is equipped with a first throttling electronic expansion valve 205, and the secondary liquid-side branch pipe 301 is equipped with a second throttling electronic expansion valve 305. The main indoor unit 2, which cools or heats the comfort space 6, and the reference indoor unit 3, which cools or heats the process space 7, are combined into a refrigeration system, and the cooling or demand of each space is controlled accordingly based on production needs.

[0039] The outdoor unit 1 is formed by connecting one or more outdoor units in parallel.

[0040] The comfort space 6 is equipped with a first humidity sensor 8 for detecting the humidity in the space.

[0041] The process space 7 is equipped with a second humidity sensor 9 for detecting the humidity within the space.

[0042] In this system, the main indoor unit 2 has a higher priority than the reference indoor unit 3. One or more outdoor units are connected to the main indoor unit and multiple reference indoor units in parallel via a set of connecting pipes to form a refrigeration system, thus combining comfort air conditioning indoor units and process air conditioning indoor units into one refrigeration system. A control board is installed on the outdoor unit to receive start / stop, frequency increase, and frequency decrease commands from the main indoor unit and multiple reference indoor units. The control board, installed on the main indoor unit and multiple reference indoor units, processes the temperature and humidity of the indoor air according to the process or comfort air conditioning requirements of the indoor units, and sends the required capacity requests to the outdoor units based on the processing results, instructing the outdoor units to perform actions such as frequency increase, frequency decrease, and start / stop.

[0043] The control method of this system is as follows:

[0044] 1) Detect the temperature Tm detected by the first temperature sensor in the indoor space corresponding to the main indoor unit (2) and the humidity RHm detected by the first humidity sensor, and compare the detected temperature Tm with the set temperature Tset, and the detected humidity RHm with the set humidity RHset.

[0045] (2) Refrigeration condition, control method for the opening degree of the electronic expansion valve of each indoor unit:

[0046] 1) When Tm > Tset + ΔT1 or RHm > RHset + ΔRH1

[0047] The first throttle electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is opened ΔS1 steps, and the second throttle electronic expansion valve of the reference indoor unit is closed ΔS2 steps. ΔS1 defaults to 36 steps, adjustable from 12 to 64 steps; ΔS2 defaults to 36 steps, adjustable from 12 to 64 steps; ΔT1 defaults to 5°C, adjustable from 3 to 6°C; ΔRH1 defaults to 8%RH, adjustable from 6 to 10%RH.

[0048] 2) When Tset + ΔT2 < Tm ≤ Tset + ΔT1 or RHset + ΔRH2 < RHm ≤ RHset + ΔRH1

[0049] The first throttle electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is opened ΔS3 steps, and the second throttle electronic expansion valve of its reference indoor unit is closed ΔS4 steps. ΔS3 defaults to 18 steps, adjustable from 4 to 48 steps; ΔS4 defaults to 18 steps, adjustable from 4 to 48 steps; ΔT2 defaults to 2°C, adjustable from 1 to 3°C; ΔRH1 defaults to 5%RH, adjustable from 3 to 6%RH.

[0050] 3) When Tset - ΔT2 < Tm ≤ Tset + ΔT2 or RHset - ΔRH2 < RHm ≤ RHset + ΔRH2

[0051] The opening degree of the first throttle electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect remains unchanged; the second throttle electronic expansion valves of its reference indoor units are adjusted according to their respective needs.

[0052] 4) When Tset - ΔT1 < Tm ≤ Tset - ΔT2 or RHset - ΔRH1 < RHm ≤ RHset - ΔRH2

[0053] The first throttle electronic expansion valve of the main indoor unit that needs to prioritize ensuring the effect is closed ΔS3 steps, and the second throttle electronic expansion valves of other reference indoor units are opened ΔS4 steps.

[0054] 5) When Tm ≤ Tset - ΔT1 or RHm ≤ RHset - ΔRH1

[0055] The first throttling electronic expansion valve of the main indoor unit, which needs to prioritize ensuring effectiveness, should be closed by ΔS1 step, while the second throttling electronic expansion valve of the reference indoor unit should be opened by ΔS2 step.

[0056] (3) Control method for the opening degree of electronic expansion valve of each indoor unit under heating conditions:

[0057] 1) When Tm > Tset + △T1

[0058] For the main indoor unit that needs to prioritize performance, the first throttling electronic expansion valve should be closed by step △S1, while the second throttling electronic expansion valve of other reference indoor units should be opened by step △S2.

[0059] 2) When Tset + △T2 <Tm≤Tset+△T1

[0060] For the main indoor unit that needs to prioritize performance, the first throttling electronic expansion valve should be closed by step △S3, while the second throttling electronic expansion valve of other reference indoor units should be opened by step △S4.

[0061] 3) When Tset - △T2 <Tm≤Tset+△T2

[0062] The opening of the first throttling electronic expansion valve of the main indoor unit, which needs to prioritize performance, should remain unchanged; the second throttling electronic expansion valve of other reference indoor units should be adjusted according to their respective needs.

[0063] 4) When Tset - △T1 <Tm≤Tset-△T2

[0064] For the main indoor unit that needs to prioritize performance, the first throttling electronic expansion valve should be opened wide by ΔS3 steps, while the second throttling electronic expansion valve of other reference indoor units should be closed narrowed by ΔS4 steps.

[0065] 5) When Tm≤Tset-△T1

[0066] The first throttling electronic expansion valve of the main indoor unit, which needs to prioritize ensuring effectiveness, should be opened by ΔS1 step, while the second throttling electronic expansion valve of other reference indoor units should be closed by ΔS2 step.

[0067] (5) When the operating mode of the main indoor unit that needs to prioritize the air conditioning effect conflicts with that of other reference indoor units, the air conditioning system shall operate in the mode required by the main indoor unit that needs to prioritize the effect. The operating modes of the other reference indoor units are as follows:

[0068] 1) When priority is needed to ensure that the main indoor unit is in heating mode and other reference indoor units are in cooling mode, the air conditioning system operates in heating mode. The main indoor unit that needs to ensure the effect is controlled by the opening of the first throttling electronic expansion valve according to the superheat; the second throttling electronic expansion valve of other reference indoor units is closed (opening degree is 0P), and the fan operates normally.

[0069] 2) When priority is needed to ensure the main indoor unit is in cooling mode and other reference indoor units are in heating mode, the air conditioning system operates in cooling mode. The main indoor unit that needs to ensure the effect is controlled by the opening of the first throttling electronic expansion valve according to the superheat; the second electronic expansion valve of other reference indoor units is closed (opening is 0P), and the fan stops running.

[0070] (6) In cooling mode, the minimum opening of the electronic expansion valve of each indoor unit is 0 steps; in heating mode, the minimum opening of the electronic expansion valve of each indoor unit is 80 steps. The maximum opening of each indoor unit in both cooling and heating modes is 480 steps. When the opening of the electronic expansion valve is lower than the minimum opening, it will not close further and will operate at the minimum opening. When the opening of the electronic expansion valve is greater than the maximum opening, it will not open further and will operate at the maximum opening.

[0071] By comprehensively adjusting the refrigerant flow through the main indoor unit and the reference indoor unit, the air conditioning effect of the main indoor unit is guaranteed. Moreover, the control method provided by this invention is simple and easy to implement, and can take into account the air conditioning effect of both the main indoor unit and the reference indoor unit.

[0072] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method for a multi-unit direct expansion internal compressor system, characterized in that: The method comprises the following steps: Step 1, first define the main indoor unit and the reference indoor unit; Step 2, detect the temperature Tm and the humidity RHm of the indoor space of the comfort space corresponding to the main indoor unit by using the first temperature sensor and the first humidity sensor, and compare the detected temperature Tm and the set temperature Tset, and the detected humidity RHm and the set humidity RHset; Step 3, control the opening degrees of the first throttling electronic expansion valve and the second throttling electronic expansion valve according to the comparison result, adjust the refrigerant flow passing through the main indoor unit and the reference indoor unit, and adjust the working mode of the main indoor unit; Step 4, when the working mode of the main indoor unit conflicts with the working mode of the reference indoor unit, the working mode of the main indoor unit is preferentially ensured; In the step 3, the specific method for adjusting the working mode of the main indoor unit by controlling the opening degree of the first throttling electronic expansion valve according to the comparison result and adjusting the refrigerant flow passing through the main indoor unit and the reference indoor unit is as follows: When Tm > Tset + △T1 or RHm > RHset + △RH1, the first throttling electronic expansion valve of the main indoor unit needs to be opened by △S1 steps, and the second throttling electronic expansion valve of the reference indoor unit needs to be closed by △S2 steps; △S1 is adjustable and is 12-64 steps; △S2 is adjustable and is 12-64 steps; △T1 is adjustable and is 3-6℃; and △RH1 is adjustable and is 6-10%RH; When Tset + △T2 < Tm ≤ Tset + △T1 or RHset + △RH2 < RHm ≤ RHset + △RH1, the first throttling electronic expansion valve of the main indoor unit needs to be opened by △S3 steps, and the second throttling electronic expansion valve of the reference indoor unit needs to be closed by △S4 steps; △S3 is adjustable and is 4-48 steps; △S4 is adjustable and is 4-48 steps; △T2 is adjustable and is 1-3℃; and △RH1 is adjustable and is 3-6%RH; When Tset - △T2 < Tm ≤ Tset + △T2 or RHset - △RH2 < RHm ≤ RHset + △RH2, the first throttling electronic expansion valve of the main indoor unit needs to maintain the same opening degree, and the second throttling electronic expansion valve of the reference indoor unit needs to be adjusted according to the respective requirements; When Tset - △T1 < Tm ≤ Tset - △T2 or RHset - △RH1 < RHm ≤ RHset - △RH2, the first throttling electronic expansion valve of the main indoor unit needs to be closed by △S3 steps, and the second throttling electronic expansion valve of the other reference indoor unit needs to be opened by △S4 steps; When Tm ≤ Tset - △T1 or RHm ≤ RHset - △RH1, the first throttling electronic expansion valve of the main indoor unit needs to be closed by △S1 steps, and the second throttling electronic expansion valve of the reference indoor unit needs to be opened by △S2 steps. ​ A system for implementing the above control method, comprising an outdoor unit (1), a main indoor unit (2) and a plurality of reference indoor units (3); the main indoor unit (2) is connected with the outdoor unit (1) through a main connection pipe group, and the reference indoor unit (3) is connected with the outdoor unit (1) through a secondary connection pipe group; the main indoor unit (2) is used for refrigerating or heating a comfort space (6); the reference indoor unit (3) is used for refrigerating or heating a process space (7), and the comfort space (6) is provided with a first temperature sensor (4) for detecting the temperature in the space, and the process space (7) is provided with a second temperature sensor (5) for detecting the temperature in the space; the priority of the main indoor unit (2) is higher than that of the reference indoor unit (3); the comfort space (6) is provided with a first humidity sensor (8) for detecting the humidity in the space; The main connection pipe group is connected by a main liquid side branch pipe (201), a main gas side branch pipe (202), a main liquid side connection pipe (203) and a main gas side connection pipe (204); the first throttling electronic expansion valve (205) is arranged on the main liquid side branch pipe (201); The secondary connection pipe group is connected by a secondary liquid side branch pipe (301), a secondary gas side branch pipe (302), a secondary liquid side connection pipe (303) and a secondary gas side connection pipe (304); the second throttling electronic expansion valve (305) is arranged on the secondary liquid side branch pipe (301); the process space (7) is provided with a second humidity sensor (9) for detecting the humidity in the space.

2. The control method of a multi-connected direct expansion indoor unit system according to claim 1, wherein The outdoor unit (1) is formed by one or more outdoor units in parallel. 3.The control method of a multi-connected direct expansion indoor unit system according to claim 1, wherein, The specific operation of step 4 is, When it is necessary to preferentially ensure that the main indoor unit needs heating mode and other reference indoor units need cooling mode, the air conditioning system operates in heating mode, and the main indoor unit that needs to ensure the effect controls the opening degree of the first throttling electronic expansion valve according to the superheat degree; the second throttling electronic expansion valve of the other reference indoor units is closed, and the fan normally operates; When it is necessary to preferentially ensure that the main indoor unit needs cooling mode and other reference indoor units need heating mode, the air conditioning system operates in cooling mode, and the main indoor unit that needs to ensure the effect controls the opening degree of the first throttling electronic expansion valve according to the superheat degree; the second throttling electronic expansion valve of the other reference indoor units is closed, and the fan stops operating.

4. The control method of a multi-connected direct expansion indoor unit system according to claim 1, wherein, In step 3, △S1 is 36 steps by default, △S2 is 36 steps by default, △T1 is 5℃ by default, △RH1 is 8%RH by default, △S3 is 18 steps by default, △S4 is 18 steps by default, △T2 is 2℃ by default, and △RH1 is 5%RH by default.

5. The control method of a multi-connected direct expansion indoor unit system according to claim 1, wherein, In the heating condition, When Tm>Tset+△T1, the first throttling electronic expansion valve of the main indoor unit that needs to ensure the effect is closed by △S1 steps, and the second throttling electronic expansion valve of the other reference indoor units is opened by △S2 steps; When Tset+△T2<Tm≤Tset+△T1, the first throttling electronic expansion valve of the main indoor unit that needs to ensure the effect is closed by △S3 steps, and the second throttling electronic expansion valve of the other reference indoor units is opened by △S4 steps; When Tset-△T2<Tm≤Tset+△T2, the first throttling electronic expansion valve of the main indoor unit which needs to be preferentially guaranteed is maintained unchanged, and the second throttling electronic expansion valve of the other reference indoor units is adjusted according to respective requirements; When Tset-△T1<Tm≤Tset-△T2, the first throttling electronic expansion valve of the main indoor unit which needs to be preferentially guaranteed is opened by △S3 steps, and the second throttling electronic expansion valve of the other reference indoor units is closed by △S4 steps; When Tm≤Tset-△T1, the first throttling electronic expansion valve of the main indoor unit which needs to be preferentially guaranteed is opened by △S1 steps, and the second throttling electronic expansion valve of the other reference indoor units is closed by △S2 steps.

Images