EP3467390A1

EP3467390A1 - Multi-split system and method for controlling heating throttling element thereof

Info

Publication number: EP3467390A1
Application number: EP17802044.2A
Authority: EP
Inventors: Bin Luo; Yuanyang Li
Original assignee: Midea Group Co Ltd; GD Midea Heating and Ventilating Equipment Co Ltd
Current assignee: Midea Group Co Ltd; GD Midea Heating and Ventilating Equipment Co Ltd
Priority date: 2016-05-23
Filing date: 2017-05-09
Publication date: 2019-04-10
Anticipated expiration: 2037-05-09
Also published as: EP3467390A4; EP3467390B1; WO2017202198A1; CN106016457B; CN106016457A

Abstract

A method for controlling a heating throttling element (35) in a multi-split system comprises: obtaining a target gas discharge pressure of a compressor, or a saturation temperature corresponding to the target gas discharge pressure (S1); controlling the compressor according to the target gas discharge pressure or the saturation temperature corresponding to the target gas discharge pressure to enable the compressor to operate stably, obtaining a high pressure and an intermediate pressure of a bypass device (30) after operation of the compressor becomes stable, and calculating a pressure difference between the high pressure and an intermediate pressure (S2); and obtaining a target pressure difference between the high pressure and an intermediate pressure of the bypass device (30), and adjusting an opening degree of the heating throttling element (35) according to the pressure difference and the target pressure difference. A multi-split system applying the method for controlling the heating throttling element is also disclosed.

Description

FIELD

The present disclosure relates to air conditioner field, and more particularly, to a method for controlling a heating throttling element in a multi-split air conditioning system and a multi-split air conditioning system.

BACKGROUND

The multi-split air conditioning system has four modes, including a pure refrigerating mode, a pure heating mode, a main refrigerating mode and a main heating mode. The main refrigerating mode and the main heating mode can simultaneously utilize condensation heat and evaporation heat of the system to achieve simultaneous refrigerating and heating, which greatly improves the energy efficiency of the system.
During the operation of the multi-split air conditioning system, the high-pressure gas of the high-pressure pipe of the outdoor unit enters the heating indoor unit, after it releases heat in the heating indoor unit, it expands into the low-pressure gas through the electronic expansion valve to return to the outdoor unit. The opening of the electronic expansion valve will affect the refrigerant flow entering the heating indoor unit, and the condensation temperature of the heating indoor unit will be adjusted. The heating indoor unit having a suitable opening will have both a greater refrigerant flow and a higher condensing temperature, thereby outputting a higher heating capacity.

SUMMARY

The present disclosure aims to solve at least one of the technical problems in the related art to at least some extent. Accordingly, an objective of the present disclosure is to provide a method for controlling a heating throttling element in a multi-split air conditioning system, the opening of the heating throttling element is adjusted by the pressure difference between the high pressure and the intermediate pressure of the shunt device, such that the multi-split air conditioning system can not only meet liquid discharge requirements, but also have good performance and energy efficiency during heating, and especially during partial load heating, user experience can be improved.
Another objective of the present disclosure is to provide a non-transitory computer readable storage medium.
Another objective of the present disclosure is to provide a multi-split air conditioning system.
In order to achieve the above objectives, embodiments of an aspect of the present disclosure provide a method for controlling a heating throttling element in a multi-split air conditioning system. The multi-split air conditioning system includes an outdoor unit, a shunt device and a plurality of indoor units. The outdoor unit includes a compressor. The shunt device includes a first heat exchanger, a second heat exchanger and a heating throttling element. An outlet of a first heat exchange flow path of the first heat exchanger is in communication with an inlet of a first heat exchange flow path of the second heat exchanger, an outlet of a second heat exchange flow path of the second heat exchanger is in communication with an inlet of a second heat exchange flow path of the first heat exchanger, the heating throttling element is disposed between the outlet of the first heat exchange flow path of the second heat exchanger and the inlet of the second heat exchange flow path of the second heat exchanger. The method includes: obtaining a target exhaust pressure of the compressor or a saturation temperature corresponding to the target exhaust pressure; controlling the compressor based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, obtaining a high pressure and an intermediate pressure of the shunt device after the compressor operates stably, and calculating a pressure difference between the high pressure and the intermediate pressure; and obtaining a target pressure difference between the high pressure and the intermediate pressure of the shunt device, and adjusting an opening of the heating throttling element based on the pressure difference and the target pressure difference.
With the method for controlling a heating throttling element in a multi-split air conditioning system according to embodiments of the present disclosure, the target exhaust pressure of the compressor or the saturation temperature corresponding to the target exhaust pressure is obtained first, and then the compressor is controlled based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, after the compressor operates stably, the high pressure and the intermediate pressure of the shunt device are obtained, and the pressure difference between the high pressure and the intermediate pressure is calculated, and finally the target pressure difference between the high pressure and the intermediate pressure of the shunt device is obtained, and the opening of the heating throttling element is adjusted based on the pressure difference and the target pressure difference, such that the multi-split air conditioning system can not only meet liquid discharge requirements, but also have good performance and energy efficiency during heating, and especially during partial load heating, user experience can be improved.
According to an embodiment of the present disclosure, adjusting the opening of the heating throttling element based on the pressure difference and the target pressure difference includes: decreasing the opening of the heating throttling element when the pressure difference is greater than the target pressure difference; and increasing the opening of the heating throttling element when the pressure difference is less than the target pressure difference.
According to an embodiment of the present disclosure, after adjusting the opening of the heating throttling element, the method further includes: determining whether the pressure difference is equal to the target pressure difference, and determining whether a saturation temperature corresponding to a current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, and determining whether an operating frequency of the compressor is greater than or equal to a maximum frequency; and controlling the opening of the heating throttling element to keep unchanged, when the pressure difference is equal to the target pressure difference, or the saturation temperature corresponding to the current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, or the operating frequency of the compressor is greater than or equal to the maximum frequency.
According to an embodiment of the present disclosure, when the pressure difference is not equal to the target pressure difference, the saturation temperature corresponding to the current exhaust pressure of the compressor is less than the saturation temperature corresponding to the target exhaust pressure of the compressor, and the operating frequency of the compressor is less than the maximum frequency, the operating frequency of the compressor is adjusted, and the opening of the heating throttling element is adjusted based on the adjusted operating frequency of the compressor.
According to an embodiment of the present disclosure, the multi-split air conditioning system is configured to operate in a heating mode, a main heating mode, or a main refrigerating mode.
In order to achieve the above objectives, the present disclosure further provides a non-transitory computer readable storage medium having computer programs stored thereon. When the computer programs are executed by a processor, the above method for controlling a heating throttling element in a multi-split air conditioning system is implemented.
With the non-transitory computer readable storage medium according to embodiments of the present disclosure, by performing the above method for controlling a heating throttling element in a multi-split air conditioning system, the opening of the heating throttling element is adjusted based on the pressure difference between the high pressure and the intermediate pressure of the shunt device, such that the multi-split air conditioning system can not only meet liquid discharge requirements, but also have good performance and energy efficiency during heating, and especially during partial load heating, user experience can be improved.
In order to achieve the above objectives, embodiments of another aspect of the present disclosure provide a multi-split air conditioning system. The multi-split air conditioning system includes an outdoor unit, a shunt device, a plurality of indoor units and a control module. The outdoor unit includes a compressor, and the shunt device includes a first heat exchanger, a second heat exchanger and a heating throttling element. An outlet of a first heat exchange flow path of the first heat exchanger is in communication with an inlet of a first heat exchange flow path of the second heat exchanger, an outlet of a second heat exchange flow path of the second heat exchanger is in communication with an inlet of a second heat exchange flow path of the first heat exchanger, the heating throttling element is disposed between the outlet of the first heat exchange flow path of the second heat exchanger and the inlet of the second heat exchange flow path of the second heat exchanger. The control module is configured to: obtain a target exhaust pressure of the compressor or a saturation temperature corresponding to the target exhaust pressure; control the compressor based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, obtain a high pressure and an intermediate pressure of the shunt device after the compressor operates stably, and calculate a pressure difference between the high pressure and the intermediate pressure; and obtain a target pressure difference between the high pressure and the intermediate pressure of the shunt device, and adjust an opening of the heating throttling element based on the pressure difference and the target pressure difference.
With the multi-split air conditioning system according to embodiments of the present disclosure, the control module obtains the target exhaust pressure of the compressor or the saturation temperature corresponding to the target exhaust pressure first, and controls the compressor based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, after the compressor operates stably, the control module obtains the high pressure and the intermediate pressure of the shunt device, then, the control module calculates the pressure difference between the high pressure and the intermediate pressure, obtains the target pressure difference between the high pressure and the intermediate pressure of the shunt device, and adjusts the opening of the heating throttling element based on the pressure difference and the target pressure difference, such that the multi-split air conditioning system can not only meet liquid discharge requirements, but also have good performance and energy efficiency during heating, and especially during partial load heating, user experience can be improved.
According to an embodiment of the present disclosure, when the control module is configured to adjust the opening of the heating throttling element based on the pressure difference and the target pressure difference, the control module is configured to: decrease the opening of the heating throttling element when the pressure difference is greater than the target pressure difference; and increase the opening of the heating throttling element when the pressure difference is less than the target pressure difference.
According to an embodiment of the present disclosure, after adjusting the opening of the heating throttling element, the control module is further configured to: determine whether the pressure difference is equal to the target pressure difference, and determine whether a saturation temperature corresponding to a current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, and determine whether an operating frequency of the compressor is greater than or equal to a maximum frequency; and control the opening of the heating throttling element to keep unchanged, when the pressure difference is equal to the target pressure difference, or the saturation temperature corresponding to the current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, or the operating frequency of the compressor is greater than or equal to the maximum frequency.
According to an embodiment of the present disclosure, when the pressure difference is not equal to the target pressure difference, the saturation temperature corresponding to the current exhaust pressure of the compressor is less than the saturation temperature corresponding to the target exhaust pressure of the compressor, and the operating frequency of the compressor is less than the maximum frequency, the control module is configured to adjust the operating frequency of the compressor, and adjust the opening of the heating throttling element based on the adjusted operating frequency of the compressor.
According to an embodiment of the present disclosure, the multi-split air conditioning system is configured to operate in a heating mode, a main heating mode, or a main refrigerating mode.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of a multi-split air conditioning system according to an embodiment of the present disclosure.
Fig. 2 is a flow chart of a method for controlling a heating throttling element in a multi-split air conditioning system according to an embodiment of the present disclosure.
Fig. 3 is a flow chart of a method for controlling a heating throttling element in a multi-split air conditioning system according to an embodiment of the present disclosure.

Reference numerals of drawings: outdoor unit 10, a plurality of indoor units 20, shunt device 30, gas-liquid separator 31, first heat exchanger 32, second heat exchanger 33, first throttling element 34, and heating throttling element 35.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, in which the same or similar elements and the elements having same or similar functions are denoted by like reference numerals. The embodiments described herein with reference to drawings are explanatory and intended to explain the present disclosure, and are not construed to limit the present disclosure.
The multi-split air conditioning system and a method for controlling a heating throttling element in a multi-split air conditioning system according to embodiments of the present disclosure will be described below with reference to the accompanying drawings.
In embodiments of the present disclosure, the multi-split air conditioning system includes an outdoor unit, a shunt device and a plurality of indoor units. The outdoor unit includes a compressor. The shunt device includes a first heat exchanger, a second heat exchanger and a heating throttling element. An outlet of a first heat exchange flow path of the first heat exchanger is in communication with an inlet of a first heat exchange flow path of the second heat exchanger, an outlet of a second heat exchange flow path of the second heat exchanger is in communication with an inlet of a second heat exchange flow path of the first heat exchanger, the heating throttling element is disposed between the outlet of the first heat exchange flow path of the second heat exchanger and the inlet of the second heat exchange flow path of the second heat exchanger.
In detail, as illustrated in Fig. 1, the multi-split air conditioning system includes an outdoor unit 10, a plurality of indoor units 20 and a shunt device 30. The outdoor unit 10 includes a compressor (not specifically shown in the drawings). The shunt device 30 includes a gas-liquid separator 31, a first heat exchanger 32, a second heat exchanger 33, a first throttling element 34 and a heating throttling element 35.
A first end of the gas-liquid separator 31 is connected to an end of the outdoor unit 10. A second end of the gas-liquid separator 31 is in communication with the inlet of the first heat exchange flow path of the first heat exchanger 32, the first throttling element 34 is disposed between the outlet of the first heat exchange flow path of the first heat exchanger 32 and the inlet of the first heat exchange flow path of the second heat exchanger 33. The heating throttling element 35 is disposed between the outlet of the first heat exchange flow path of the second heat exchanger 33 and the inlet of the second heat exchange flow path of the second heat exchanger 33, the outlet of the second heat exchange flow path of the second heat exchanger 33 is in communication with the inlet of the second heat exchange flow path of the first heat exchanger 32, and the outlet of the second heat exchange flow path of the first heat exchanger 32 is in communication with the another end of the outdoor unit 10 and an end of the refrigerating indoor unit, respectively. Another end of the refrigerating indoor unit is in communication with the outlet of the first heat exchange flow path of the second heat exchanger 33, a third end of the gas-liquid separator 31 is in communication with an end of the heating indoor unit, and another end of the heating indoor unit is in communication with the inlet of the first heat exchange flow path of the second heat exchanger 33. The first throttling element and the heating throttling element may be electronic expansion valves, and the first heat exchanger and the second heat exchanger may be plate heat exchangers.
During heating operation of the multi-split air conditioning system (including the multi-split air conditioning system operating in a heating mode, a main heating mode and a main refrigerating mode), and especially during partial load heating operation, when the opening of the heating throttling element is too small, the pressure difference (i.e., the pressure difference ΔP = Ps1 - Ps2 between the high pressure Ps1 and the intermediate pressure Ps2 of the shunt device) between inlet and outlet of the heating indoor unit will be reduced, and the refrigerant flow rate and flow velocity entering the heating indoor unit will be reduced. In this case, since the indoor temperature of the room where the heating indoor unit is located is generally low, liquid storage may occur in the heating indoor unit, and the outlet temperature of the heating indoor unit will be reduced, such that the heating capacity will be attenuated, thus measures need to be taken to drain excess liquid from the heating indoor unit. Moreover, the smaller pressure difference between inlet and outlet will not cause the supercooling degree of the heating indoor unit to be too large, but also cause the upstream supercooling degree SCm2=Tps2-Tm2 (in which, Tps2 denotes the saturation temperature corresponding to the intermediate pressure value of the shunt device, i.e., the saturation temperature corresponding to the upstream pressure value of the heating throttling element, and Tm2 denotes the upstream temperature value of the heating throttling element) of the heating throttling element to be relatively high.
However, when the opening of the heating throttling element is too large, the pressure difference between inlet and outlet of the heating indoor unit will be increased, and the refrigerant flow rate and flow velocity entering the heating indoor unit will be increased. In this case, although the heating indoor unit is not prone to liquid storage, the outlet supercooling degree of the heating indoor unit will be too small, and the upstream supercooling degree SCm2 of the heating throttling element will be too small, and there may be gas upstream of the valve, which may cause system instability. Moreover, when the opening of the heating throttling element is too large, the operating frequency of the compressor will increase, the system energy efficiency will decrease, and the high pressure may fail to reach, and the exhaust superheat of the compressor may sometimes be low.
When the heating element does not have liquid accumulation, the opening of the heating throttling element is relatively small. In this case, the exhaust superheat of the compressor is relatively high, the high pressure is relatively high, and the operating frequency of the compressor is relatively low, and the system energy efficiency is high. Therefore, by controlling reasonable pressure difference ΔP=Ps1-Ps2 between the high pressure Ps1 and the intermediate pressure Ps2, the system can not only satisfy liquid discharge requirements, but also have good heating and energy efficiency performance.
Fig. 2 is a flow chart of a method for controlling a heating throttling element in a multi-split air conditioning system according to an embodiment of the present disclosure. As illustrated in Fig. 2, the method may include following operations.
At block S1, a target exhaust pressure of the compressor or a saturation temperature corresponding to the target exhaust pressure is obtained.
At block S2, the compressor is controlled based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, and after the compressor operates stably, a high pressure and an intermediate pressure of the shunt device are obtained, and a pressure difference between the high pressure and the intermediate pressure is calculated.
In detail, when the multi-split air conditioning system operates in the heating mode, the main heating mode or the main refrigerating mode, the exhaust pressure Pc of the compressor can be obtained in real time by a pressure sensor disposed at an exhaust port of the compressor, or after the exhaust pressure Pc of the compressor is obtained, the saturation temperature Tc corresponding to the exhaust pressure can be obtained based on the exhaust pressure Pc. Then, based on a difference between the exhaust pressure Pc of the compressor (or the saturation temperature Tc corresponding to the exhaust pressure) and a target exhaust pressure Pcs (or a saturation temperature Tcs corresponding to the target exhaust pressure), PI (Proportional Integral) adjustment is performed on the operating frequency of the compressor, to obtain a new exhaust pressure Pc (or a saturation pressure Tc corresponding to the new exhaust pressure) of the compressor, a high pressure Ps1 and an intermediate pressure Ps2 of the shunt device after the compressor operates stably. The high pressure Ps1 can be obtained by a pressure sensor disposed at the outlet of the first heat exchange flow path of the first heat exchanger of the shunt device, and the intermediate pressure Ps2 can be obtained by a pressure sensor disposed at the inlet of the first heat exchange flow path of the second heat exchanger.
At block S3, a target pressure difference between the high pressure and the intermediate pressure of the shunt device is obtained, and an opening of the heating throttling element is adjusted based on the pressure difference and the target pressure difference.
It should be noted that, the target pressure difference ΔPs is the pressure difference between the high pressure and the intermediate pressure of the shunt device when the system has no liquid accumulation, and the target pressure difference is obtained by experimental verification. The target pressure difference ΔPs is generally a small value that can ensure system refrigerant flow rate and satisfy high pressure.
According to an embodiment of the present disclosure, adjusting the opening of the heating throttling element based on the pressure difference and the target pressure difference includes: decreasing the opening of the heating throttling element when the pressure difference is greater than the target pressure difference, and increasing the opening of the heating throttling element when the pressure difference is less than the target pressure difference.
In other words, under the premise that the compressor is adjusted to obtain the new exhaust pressure Pc of the compressor (or the saturation temperature Tc corresponding to the new exhaust pressure), the high pressure Ps1 and the intermediate pressure Ps2, PI adjustment is performed on the heating throttling element from an initial opening based on the pressure difference ΔP between the high pressure Ps1 and the intermediate pressure Ps2 and the target pressure difference ΔPs.
When ΔP > ΔPs, the opening of the heating throttling element is decreased, in this case, the exhaust pressure Pc of the compressor (or the saturation temperature Tc corresponding to the exhaust pressure) is increased, and due to the flow rate is decreased, ΔP is decreased.
When ΔP < ΔPs, the opening of the heating throttling element is increased, in this case, the exhaust pressure Pc of the compressor (or the saturation temperature Tc corresponding to the exhaust pressure) is decreased, and due to the flow rate is increased, ΔP is increased.
According to an embodiment of the present disclosure, after the opening of the heating throttling element is adjusted, the method further includes following operations. It is determined whether the pressure difference is equal to the target pressure difference, and it is determined whether a saturation temperature corresponding to a current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, and it is determined whether an operating frequency of the compressor is greater than or equal to a maximum frequency, when the pressure difference is equal to the target pressure difference, or the saturation temperature corresponding to the current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, or the operating frequency of the compressor is greater than or equal to the maximum frequency, the opening of the heating throttling element is controlled to keep unchanged.
When the pressure difference is not equal to the target pressure difference, the saturation temperature corresponding to the current exhaust pressure of the compressor is less than the saturation temperature corresponding to the target exhaust pressure of the compressor, and the operating frequency of the compressor is less than the maximum frequency, the operating frequency of the compressor is adjusted, and the opening of the heating throttling element is adjusted based on the adjusted operating frequency of the compressor.
In detail, after the opening of the heating throttling element is adjusted, it is further determined whether ΔP = ΔPs and Pc ≥ Pcs (or Tc ≥ Tcs), or whether the compressor is in full operating frequency. When ΔP=ΔP, or ΔP≠ΔPs but Pc≥Pcs (or Tc≥Tcs), or ΔP≠ΔPs but the compressor is in full operating frequency, the opening of the heating throttling element is controlled to keep unchanged. Otherwise, the operating frequency of the compressor is adjusted, and the opening of the heating throttling element is readjusted until the above conditions are met, indicating that the system has reached a steady state, and the opening of the heating throttling element can be stabilized at the opening, such that the system can have better system performance and energy efficiency under heating, especially under partial load heating.
In order to make those skilled in the art clearly understand the present disclosure, Fig. 3 is a flow chart of a method for controlling a heating throttling element in a multi-split air conditioning system according to an embodiment of the present disclosure.
As shown in Fig. 3, the method for controlling a heating throttling element in a multi-split air conditioning system may include the following operations.
At block 101, a current opening of the heating throttling element is obtained.
At block 102, PI adjustment is performed on the operating frequency of the compressor based on a difference between the exhaust pressure Pc (or the saturation temperature Tc corresponding to the exhaust pressure) and the target exhaust pressure Pcs (or the saturation temperature Tcs corresponding to the target exhaust pressure), to obtain a new exhaust pressure Pc (or a saturation temperature Tc corresponding to the new exhaust pressure), a high pressure Ps1 and an intermediate pressure Ps2.
At block 103, PI adjustment is performed on the opening of the heating throttling element based on the difference between the pressure difference ΔP and the target pressure difference ΔPs.
At block 104, when ΔP>ΔPs, the opening of the heating throttling element is decreased.
At block 105, when ΔP<ΔPs, the opening of the heating throttling element is increased.
At block 106, it is determined whether ΔP=ΔPs and Pc≥Pcs (or Tc≥Tcs), or whether the compressor is in full operating frequency, if yes, block S107 is performed, and otherwise, block S101 is returned.
At block 107, the heating throttling element is kept at the opening and the system operates stably.
As described above, with the method for controlling a heating throttling element in a multi-split air conditioning system according to embodiments of the present disclosure, the target exhaust pressure of the compressor or the saturation temperature corresponding to the target exhaust pressure is obtained first, and then the compressor is controlled based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, after the compressor operates stably, the high pressure and the intermediate pressure of the shunt device are obtained, and the pressure difference between the high pressure and the intermediate pressure is calculated, and finally the target pressure difference between the high pressure and the intermediate pressure of the shunt device is obtained, and the opening of the heating throttling element is quickly adjusted based on the pressure difference and the target pressure difference, such that the multi-split air conditioning system can not only meet liquid discharge requirements, but also have good performance and energy efficiency during heating, and especially during partial load heating, user experience can be improved.
Furthermore, the present disclosure further provides a non-transitory computer readable storage medium having computer programs stored thereon. When the computer programs are executed by a processor, the above method for controlling a heating throttling element in a multi-split air conditioning system is implemented.
With the non-transitory computer readable storage medium according to embodiments of the present disclosure, by performing the above method for controlling a heating throttling element in a multi-split air conditioning system, the opening of the heating throttling element is adjusted based on the pressure difference between the high pressure and the intermediate pressure of the shunt device, such that the multi-split air conditioning system can not only meet liquid discharge requirements, but also have good performance and energy efficiency during heating, and especially during partial load heating, user experience can be improved.
Fig. 1 is a schematic diagram of a multi-split air conditioning system according to an embodiment of the present disclosure. As illustrated in Fig. 1, the multi-split air conditioning system includes an outdoor unit 10, a plurality of indoor units 20, a shunt device 30 and a control module (not specifically shown in the drawings).
The outdoor unit 10 includes a compressor (not specifically shown in the drawings). The shunt device 30 includes a first heat exchanger 32, a second heat exchanger 33 and a heating throttling element 35. An outlet of a first heat exchange flow path of the first heat exchanger 32 is in communication with an inlet of a first heat exchange flow path of the second heat exchanger 33, an outlet of a second heat exchange flow path of the second heat exchanger 33 is in communication with an inlet of a second heat exchange flow path of the first heat exchanger 32, the heating throttling element 35 is disposed between the outlet of the first heat exchange flow path of the second heat exchanger 33 and the inlet of the second heat exchange flow path of the second heat exchanger 33.
The control module is configured to obtain a target exhaust pressure of the compressor or a saturation temperature corresponding to the target exhaust pressure, control the compressor based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, and obtain a high pressure and an intermediate pressure of the shunt device 30 after the compressor operates stably, and calculate a pressure difference between the high pressure and the intermediate pressure, and obtain a target pressure difference between the high pressure and the intermediate pressure of the shunt device 30, and adjust an opening of the heating throttling element 35 based on the pressure difference and the target pressure difference. The target pressure difference is the pressure difference between the high pressure and the intermediate pressure of the shunt device when the system has no liquid accumulation, and the target pressure difference is obtained by experimental verification. The target pressure difference is generally a small value that can ensure system refrigerant flow rate and satisfy high pressure.
According to an embodiment of the present disclosure, when the control module is configured to adjust the opening of the heating throttling element based on the pressure difference and the target pressure difference, the control module is configured to decrease the opening of the heating throttling element 35 when the pressure difference is greater than the target pressure difference, and increase the opening of the heating throttling element 35 when the pressure difference is less than the target pressure difference.
In detail, during heating operation of the multi-split air conditioning system (including the multi-split air conditioning system operating in the heating mode, the main heating mode and the main refrigerating mode), and especially during partial load heating operation, the control module first obtains the exhaust pressure Pc of the compressor in real time by a pressure sensor disposed at an exhaust port of the compressor, or obtains the saturation temperature Tc corresponding to the exhaust pressure based on the exhaust pressure Pc after the exhaust pressure Pc of the compressor is obtaine. Then, based on a difference between the exhaust pressure Pc of the compressor (or the saturation temperature Tc corresponding to the exhaust pressure) and a target exhaust pressure Pcs (or a saturation temperature Tcs corresponding to the target exhaust pressure), the control module performs PI (Proportional Integral) adjustment on the operating frequency of the compressor, to obtain a new exhaust pressure Pc of the compressor (or the saturation pressure Tc corresponding to the new exhaust pressure), a high pressure Ps1 and an intermediate pressure Ps2 of the shunt device 30 after the compressor operates stably. The high pressure Ps1 can be obtained by a pressure sensor disposed at the outlet of the first heat exchange flow path of the first heat exchanger 32 of the shunt device 30, and the intermediate pressure Ps2 can be obtained by the pressure sensor disposed at the inlet of the first heat exchange flow path of the second heat exchanger 33.
Under the premise that the compressor is adjusted to obtain the new exhaust pressure Pc of the compressor (or the saturation temperature Tc corresponding to the new exhaust pressure), the high pressure Ps1 and the intermediate pressure Ps2, the control module performs PI adjustment on the heating throttling element 35 from an initial opening based on the pressure difference ΔP between the high pressure Ps1 and the intermediate pressure Ps2 and the target pressure difference ΔPs.
When ΔP > ΔPs, the control module controls the opening of the heating throttling element to be decreased, in this case, the exhaust pressure Pc of the compressor (or the saturation temperature Tc corresponding to the exhaust pressure) is increased, and due to the flow rate is decreased, ΔP is decreased.
When ΔP < ΔPs, the control module controls the opening of the heating throttling element to be increased, in this case, the exhaust pressure Pc of the compressor (or the saturation temperature Tc corresponding to the exhaust pressure) is decreased, and due to the flow rate is increased, ΔP is increased.
According to an embodiment of the present disclosure, after the opening of the heating throttling element 35 is adjusted, the control module is further configured to determine whether the pressure difference is equal to the target pressure difference, and determine whether a saturation temperature corresponding to a current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, and determine whether an operating frequency of the compressor is greater than or equal to a maximum frequency, and control the opening of the heating throttling element 35 to keep unchanged when the pressure difference is equal to the target pressure difference, or the saturation temperature corresponding to the current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, or the operating frequency of the compressor is greater than or equal to the maximum frequency.
When the pressure difference is not equal to the target pressure difference, the saturation temperature corresponding to the current exhaust pressure of the compressor is less than the saturation temperature corresponding to the target exhaust pressure of the compressor, and the operating frequency of the compressor is less than the maximum frequency, the control module is configured to adjust the operating frequency of the compressor, and adjust the opening of the heating throttling element 35 based on the adjusted operating frequency of the compressor.
In detail, after the opening of the heating throttling element 35 is adjusted, the control module further determines whether ΔP = ΔPs and Pc ≥ Pcs (or Tc ≥ Tcs), or whether the compressor is in full operating frequency. When ΔP=ΔP, or ΔP≠ΔPs but Pc≥Pcs (or Tc≥ Tcs), or ΔP≠ΔPs but the compressor is in full operating frequency, the control module controls the opening of the heating throttling element 35 to keep unchanged. Otherwise, the control module first adjusts the operating frequency of the compressor first, and readjusts the opening of the heating throttling element 35 until the above conditions are met, indicating that the system has reached a steady state, and the opening of the heating throttling element 35 can be stabilized at the opening, such that the system can have better system performance and energy efficiency under heating, especially under partial load heating.
With the multi-split air conditioning system according to embodiments of the present disclosure, the control module obtains the target exhaust pressure of the compressor or the saturation temperature corresponding to the target exhaust pressure first, and controls the compressor based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, after the compressor operates stably, the control module obtains the high pressure and the intermediate pressure of the shunt device, then, the control module calculates the pressure difference between the high pressure and the intermediate pressure, obtains the target pressure difference between the high pressure and the intermediate pressure of the shunt device, and adjusts the opening of the heating throttling element based on the pressure difference and the target pressure difference, such that the multi-split air conditioning system can not only meet liquid discharge requirements, but also have good performance and energy efficiency during heating, and especially during partial load heating, user experience can be improved.
In the description of the present disclosure, terms such as "first" and "second" are used herein for purposes of description and are not intended to indicate or imply relative importance or significance or to imply the number of indicated technical features. Thus, the feature defined with "first" and "second" may include at least one feature. In the description of the present disclosure, unless it is specified otherwise, "a plurality of' means two or more than two.
In the present disclosure, unless specified or limited otherwise, the terms "mounted," "connected," "coupled," "fixed" and the like are used broadly, and may be, for example, fixed connections, detachable connections, or integral connections; may also be mechanical or electrical connections; may also be direct connections or indirect connections via intervening structures; may also be inner communications of two elements, which can be understood by those skilled in the art according to specific situations.
Reference throughout this specification to "an embodiment," "some embodiments," "an example," "a specific example," or "some examples," means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. The appearances of the above phrases in various places throughout this specification are not necessarily referring to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples. In addition, different embodiments or examples and features of different embodiments or examples described in the specification may be combined by those skilled in the art without mutual contradiction.
Any process or method described in a flow chart or described herein in other ways may be understood to include one or more modules, segments or portions of codes of executable instructions for achieving specific logical functions or steps in the process, and the scope of a preferred embodiment of the present disclosure includes other implementations, which should be understood by those skilled in the art.
The logic and/or step described in other manners herein or shown in the flow chart, for example, a particular sequence table of executable instructions for realizing the logical function, may be specifically achieved in any computer readable medium to be used by the instruction execution system, device or equipment (such as the system based on computers, the system including processors or other systems capable of obtaining the instruction from the instruction execution system, device and equipment and executing the instruction), or to be used in combination with the instruction execution system, device and equipment. As to the specification, "the computer readable medium" may be any device adaptive for including, storing, communicating, propagating or transferring programs to be used by or in combination with the instruction execution system, device or equipment. More specific examples of the computer readable medium include but are not limited to: an electronic connection (an electronic device) with one or more wires, a portable computer enclosure (a magnetic device), a random access memory (RAM), a read only memory (ROM), an erasable programmable read-only memory (EPROM or a flash memory), an optical fiber device and a portable compact disk read-only memory (CDROM). In addition, the computer readable medium may even be a paper or other appropriate medium capable of printing programs thereon, this is because, for example, the paper or other appropriate medium may be optically scanned and then edited, decrypted or processed with other appropriate methods when necessary to obtain the programs in an electric manner, and then the programs may be stored in the computer memories.
It should be understood that each part of the present disclosure may be realized by the hardware, software, firmware or their combination. In the above embodiments, a plurality of steps or methods may be realized by the software or firmware stored in the memory and executed by the appropriate instruction execution system. For example, if it is realized by the hardware, likewise in another embodiment, the steps or methods may be realized by one or a combination of the following techniques known in the art: a discrete logic circuit having a logic gate circuit for realizing a logic function of a data signal, an application-specific integrated circuit having an appropriate combination logic gate circuit, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.
Although embodiments of present disclosure have been shown and described above, it should be understood that above embodiments are just explanatory, and cannot be construed to limit the present disclosure, for those skilled in the art, changes, alternatives, and modifications can be made to the embodiments without departing from spirit, principles and scope of the present disclosure.

Claims

A method for controlling a heating throttling element in a multi-split air conditioning system, the multi-split air conditioning system comprising an outdoor unit, a shunt device and a plurality of indoor units, the outdoor unit comprising a compressor, the shunt device comprising a first heat exchanger, a second heat exchanger and a heating throttling element, an outlet of a first heat exchange flow path of the first heat exchanger being in communication with an inlet of a first heat exchange flow path of the second heat exchanger, an outlet of a second heat exchange flow path of the second heat exchanger being in communication with an inlet of a second heat exchange flow path of the first heat exchanger, the heating throttling element being disposed between the outlet of the first heat exchange flow path of the second heat exchanger and the inlet of the second heat exchange flow path of the second heat exchanger, the method comprising:
obtaining a target exhaust pressure of the compressor or a saturation temperature corresponding to the target exhaust pressure;

controlling the compressor based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, obtaining a high pressure and an intermediate pressure of the shunt device after the compressor operates stably, and calculating a pressure difference between the high pressure and the intermediate pressure; and

obtaining a target pressure difference between the high pressure and the intermediate pressure of the shunt device, and adjusting an opening of the heating throttling element based on the pressure difference and the target pressure difference.
The method according to claim 1, wherein adjusting the opening of the heating throttling element based on the pressure difference and the target pressure difference comprises:
decreasing the opening of the heating throttling element when the pressure difference is greater than the target pressure difference; and

increasing the opening of the heating throttling element when the pressure difference is less than the target pressure difference.
The method according to claim 1 or 2, wherein after adjusting the opening of the heating throttling element, the method further comprises:
determining whether the pressure difference is equal to the target pressure difference, and determining whether a saturation temperature corresponding to a current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, and determining whether an operating frequency of the compressor is greater than or equal to a maximum frequency; and

controlling the opening of the heating throttling element to keep unchanged, when the pressure difference is equal to the target pressure difference, or the saturation temperature corresponding to the current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, or the operating frequency of the compressor is greater than or equal to the maximum frequency.
The method according to claim 3, wherein when the pressure difference is not equal to the target pressure difference, or the saturation temperature corresponding to the current exhaust pressure of the compressor is less than the saturation temperature corresponding to the target exhaust pressure of the compressor, and the operating frequency of the compressor is less than the maximum frequency, the operating frequency of the compressor is adjusted, and the opening of the heating throttling element is adjusted based on the adjusted operating frequency of the compressor.
The method according to any one of claims 1 to 4, wherein the multi-split air conditioning system is configured to operate in a heating mode, a main heating mode, or a main refrigerating mode.
A multi-split air conditioning system, comprising:
an outdoor unit, comprising a compressor;

a plurality of indoor units;

a shunt device, comprising a first heat exchanger, a second heat exchanger and a heating throttling element, an outlet of a first heat exchange flow path of the first heat exchanger being in communication with an inlet of a first heat exchange flow path of the second heat exchanger, an outlet of a second heat exchange flow path of the second heat exchanger being in communication with an inlet of a second heat exchange flow path of the first heat exchanger, the heating throttling element being disposed between the outlet of the first heat exchange flow path of the second heat exchanger and the inlet of the second heat exchange flow path of the second heat exchanger; and

a control module, configured to:
obtain a target exhaust pressure of the compressor or a saturation temperature corresponding to the target exhaust pressure;

control the compressor based on the target exhaust pressure or the saturation temperature corresponding to the target exhaust pressure to make the compressor operate stably, obtain a high pressure and an intermediate pressure of the shunt device after the compressor operates stably, and calculate a pressure difference between the high pressure and the intermediate pressure; and

obtain a target pressure difference between the high pressure and the intermediate pressure of the shunt device, and adjust an opening of the heating throttling element based on the pressure difference and the target pressure difference.
The multi-split air conditioning system according to claim 6, wherein when the control module is configured to adjust the opening of the heating throttling element based on the pressure difference and the target pressure difference, the control module is configured to:
decrease the opening of the heating throttling element when the pressure difference is greater than the target pressure difference; and

increase the opening of the heating throttling element when the pressure difference is less than the target pressure difference.
The multi-split air conditioning system according to claim 6 or 7, wherein after adjusting the opening of the heating throttling element, the control module is further configured to:
determine whether the pressure difference is equal to the target pressure difference, and determine whether a saturation temperature corresponding to a current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, and determine whether an operating frequency of the compressor is greater than or equal to a maximum frequency; and

control the opening of the heating throttling element to keep unchanged, when the pressure difference is equal to the target pressure difference, or the saturation temperature corresponding to the current exhaust pressure of the compressor is greater than or equal to the saturation temperature corresponding to the target exhaust pressure of the compressor, or the operating frequency of the compressor is greater than or equal to the maximum frequency.
The multi-split air conditioning system according to claim 8, wherein when the pressure difference is not equal to the target pressure difference, the saturation temperature corresponding to the current exhaust pressure of the compressor is less than the saturation temperature corresponding to the target exhaust pressure of the compressor, and the operating frequency of the compressor is less than the maximum frequency, the control module is configured to adjust the operating frequency of the compressor, and adjust the opening of the heating throttling element based on the adjusted operating frequency of the compressor.
The multi-split air conditioning system according to any one of claims 6 to 9, wherein the multi-split air conditioning system is configured to operate in a heating mode, a main heating mode, or a main refrigerating mode.
A non-transitory computer readable storage medium, having computer programs stored thereon, wherein when the computer programs are executed by a processor, the method for controlling a heating throttling element in a multi-split air conditioning system according to any one of claims 1-5 is implemented.