FIELD
[0001] The present disclosure relates to air conditioner technology field, and more particularly
to a method and a device for controlling refrigerant distribution of a multi-split
air-conditioning system.
BACKGROUND
[0002] When a multi-split air-conditioning system with two-pipe heating recycle is operating
under a main heating mode, refrigerant is recoolezd via a heat exchanger, and then
parts of the recooled refrigerant enters a low pressure pipe of an outdoor unit via
an electronic expansion valve and another heat exchanger, and the rest of the recooled
refrigerant finally enters the low pressure pipe of the outdoor unit after entering
a cooling indoor unit to absorb heat via another electronic expansion valve.
[0003] Refrigerant volume entering the cooling indoor unit and discharge superheat of the
cooling indoor unit will be affected by an opening of the electronic expansion valve.
When the refrigerant volume entering the cooling indoor unit is reduced because of
the inappropriate opening of the electronic expansion valve, the cooling effect of
the cooling indoor unit will be affected; and when the discharge superheat is reduced
because of the inappropriate opening of the electronic expansion valve, the liquid
strike on a compressor will be caused and the compressor is damaged.
SUMMAY
[0004] Embodiments of the present disclosure seek to solve at least one of the problems
existing in the related art to at least some extent. Therefore, a first objective
of the present disclosure is to provide a method for controlling refrigerant distribution
of a multi-split air-conditioning system, which may ensure the cooling effect of the
cooling indoor unit and may avoid the liquid strike on the compressor under the main
heating mode, and ensure the compressor to operate safely and reliably.
[0005] A second objective of the present disclosure is to provide a device for controlling
refrigerant distribution of a multi-split air-conditioning system.
[0006] According to a first aspect of embodiments of the present disclosure, a method for
controlling refrigerant distribution of a multi-split air-conditioning system is provided.
The multi-split air-conditioning system includes: a re-cooling system including a
first heat exchanger, a second heat exchanger, a first electronic expansion valve
and a second electronic expansion valve, and a flow distributing device. The method
includes followings: when the multi-split air-conditioning system enters a main heating
mode, controlling the second electronic expansion valve to close; controlling an electronic
expansion valve corresponding to a cooling indoor unit to perform an opening adjustment;
when an opening of the electronic expansion valve corresponding to the cooling indoor
unit reaches a maximum opening, calculating a target opening of the second electronic
expansion valve according to a total opening and the maximum opening of the electronic
expansion valve corresponding to the cooling indoor unit; and controlling the second
electronic expansion valve according to the target opening.
[0007] With the method for controlling refrigerant distribution of a multi-split air-conditioning
system in embodiments of the present disclosure, when the multi-split air-conditioning
system enters the main cooling mode, first the second electronic expansion valve is
controlled to close, the opening of the electronic expansion valve corresponding to
the cooling indoor unit is controlled, and after the opening of the electronic expansion
valve corresponding to the cooling indoor unit reaches the maximum opening, the opening
of the second electronic expansion valve is controlled according to the total opening.
Therefore, the refrigerating capacity of the cooling indoor unit may be controlled
by controlling the refrigerant volume flowing into the cooling indoor unit so as to
ensure the cooling effect of the cooling indoor unit. Meanwhile, according to the
control of the total opening, the discharge superheat is effectively controlled, such
that the liquid strike on the compressor may be avoided, and the compressor is ensured
to operate safely and reliably.
[0008] In addition, the method according to the above embodiments may further include additional
technical features as follows.
[0009] In an embodiment of the present disclosure, the total opening is obtained according
to following acts of: when the multi-split air-conditioning system enters a pure heating
mode, obtaining a discharge superheat; and calculating the total opening using a PI
(Proportional-Integral) algorithm according to the discharge superheat.
[0010] In an embodiment of the present disclosure, the target opening of the second electronic
expansion valve is calculated by a formula of ΔEXV2 = EXV2(PI)-EV(cooling indoor)MAX*(A
EV(cooling indoor)/A
EXV2), where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI)
is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic
expansion valve corresponding to the cooling indoor unit, A
EV(cooling indoor) is a valve circulating area of the electronic expansion valve corresponding to the
cooling indoor unit, and A
EXV2 is a valve circulating area of the second electronic expansion valve.
[0011] According to a second aspect of embodiments of the present disclosure, a device for
controlling refrigerant distribution of a multi-split air-conditioning system is provided.
The multi-split air-conditioning system includes: a re-cooling system including a
first heat exchanger, a second heat exchanger, a first electronic expansion valve
and a second electronic expansion valve, and a flow distributing device. The device
for controlling refrigerant distribution of a multi-split air-conditioning system
includes: a first control module, configured to control the second electronic expansion
valve to close when the multi-split air-conditioning system enters a main heating
mode; a second control module, configured to control an electronic expansion valve
corresponding to a cooling indoor unit to perform an opening adjustment; a calculating
module, configured to calculate a target opening of the second electronic expansion
valve according to a total opening and a maximum opening of the electronic expansion
valve corresponding to the cooling indoor unit when an opening of the electronic expansion
valve corresponding to the cooling indoor unit reaches the maximum opening; and a
third control module, configured to control the second electronic expansion valve
according to the target opening.
[0012] With the device for controlling refrigerant distribution of a multi-split air-conditioning
system in embodiments of the present disclosure, when the multi-split air-conditioning
system enters the main cooling mode, first the second electronic expansion valve is
controlled to close, the opening of the electronic expansion valve corresponding to
the cooling indoor unit is controlled, and after the opening of the electronic expansion
valve corresponding to the cooling indoor unit reaches the maximum opening, the opening
of the second electronic expansion valve is controlled according to the total opening.
Therefore, the refrigerating capacity of the cooling indoor unit may be controlled
by controlling the refrigerant volume flowing into the cooling indoor unit so as to
ensure the cooling effect of the cooling indoor unit. Meanwhile, according to the
control of the total opening, the discharge superheat is effectively controlled, such
that the liquid strike on the compressor may be avoided, and the compressor is ensured
to operate safely and reliably.
[0013] In addition, the device according to the above embodiments may further include additional
technical features as follows.
[0014] In an embodiment of the present disclosure, the total opening is obtained according
to following acts of: when the multi-split air-conditioning system enters a pure heating
mode, obtaining a discharge superheat; and calculating the total opening using a PI
(Proportional-Integral) algorithm according to the discharge superheat.
[0015] In an embodiment of the present disclosure, the target opening of the second electronic
expansion valve is calculated by a formula of ΔEXV2 = EXV2(PI)-EV(cooling indoor)MAX*(A
EV(cooling indoor)/A
EXV2), where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI)
is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic
expansion valve corresponding to the cooling indoor unit, A
EV(cooling indoor) is a valve circulating area of the electronic expansion valve corresponding to the
cooling indoor unit, and A
EXV2 is a valve circulating area of the second electronic expansion valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016]
Fig. 1 is a flow chart of a method for controlling refrigerant distribution of a multi-split
air-conditioning system according to an embodiment of the present disclosure.
Fig. 2 is a schematic diagram of a multi-split air-conditioning system according to
an embodiment of the present disclosure.
Fig. 3 is a block diagram of a device for controlling refrigerant distribution of
a multi-split air-conditioning system according to an embodiment of the present disclosure.
DETAILED DESCRIPTION
[0017] Exemplary embodiments of the present disclosure will be described in detail herein,
and examples thereof are illustrated in accompanying drawings. Throughout figures
referred by the following description, the same reference number in different figures
indicates the same or similar elements unless otherwise stated. The embodiments described
herein with reference to accompanying drawings are explanatory, illustrative, and
used to generally interprete the present disclosure, but shall not be construed to
limit the present disclosure.
[0018] Fig. 1 is a flow chart of a method for controlling refrigerant distribution of a
multi-split air-conditioning system according to an embodiment of the present disclosure.
[0019] In an embodiment of the present disclosure, as shown in Fig. 2, the multi-split air-conditioning
system includes: a re-cooling system and a flow distributing device. The re-cooling
system includes a first heat exchanger, a second heat exchanger, a first electronic
expansion valve and a second electronic expansion valve.
[0020] As shown in Fig. 1, the method for controlling refrigerant distribution of a multi-split
air-conditioning system includes followings.
[0021] In step S101, when the multi-split air-conditioning system enters a main heating
mode, the second electronic expansion valve is controlled to close.
[0022] In step S102, an electronic expansion valve corresponding to a cooling indoor unit
is controlled to perform an opening adjustment.
[0023] Generally, in a pure heating mode, the discharge superheat of an outdoor unit may
be controlled by controlling an opening of the second electronic expansion valve.
In the main heating mode, the discharge superheat of the outdoor unit and a refrigerant
volume flowing into the cooling indoor unit are controlled by controlling the opening
of the second electronic expansion valve and an opening of the electronic expansion
valve corresponding to the cooling indoor unit. Specifically, the opening of the second
electronic expansion valve and the opening of the electronic expansion valve corresponding
to the cooling indoor unit may be calculated according to the refrigerant volume required
by the cooling indoor unit for cooling. In an embodiment of the present disclosure,
in the main heating mode, since the electronic expansion valve corresponding to the
cooling indoor unit may also play the role of the second electronic expansion valve,
i.e. the refrigerant through the cooling indoor unit, which is satisfied with the
requirement of indoor cooling, will also obtain the superheat, such that the effect
of avoiding the liquid strike on the compressor may be satisfied. Therefore the opening
of the electronic expansion valve corresponding to the cooling indoor unit may be
controlled preferentially in that mode, that is, in step S101, before controlling
the electronic expansion valve corresponding to the cooling indoor unit to perform
the opening adjustment, the second electronic expansion valve may be controlled to
close, and then the control on the discharge superheat of the outdoor unit and the
refrigerant volume flowing into the cooling indoor unit may also be realized.
[0024] In step S103, when an opening of the electronic expansion valve corresponding to
the cooling indoor unit reaches a maximum opening, a target opening of the second
electronic expansion valve is calculated according to a total opening and the maximum
opening of the electronic expansion valve corresponding to the cooling indoor unit.
[0025] When the opening of the electronic expansion valve corresponding to the cooling indoor
unit reaches the maximum opening, the discharge superheat of the outdoor unit may
not be controlled. Then, the opening of the second electronic expansion valve needs
to be adjusted to control the discharge superheat of the outdoor unit. Specifically,
the target opening of the second electronic expansion valve is calculated by a formula
of:

where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI)
is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic
expansion valve corresponding to the cooling indoor unit, A
EV(cooling indoor) is a valve circulating area of the electronic expansion valve corresponding to the
cooling indoor unit, and A
EXV2 is a valve circulating area of the second electronic expansion valve.
[0026] The total opening may be obtained by calculating in the pure heating mode. When the
multi-split air-conditioning system enters the pure heating mode, the discharge superheat,
the discharge temperature and the returned-gas superheat of the outdoor unit are controlled
by the second electronic expansion valve, such that the reliability of the compressor
is ensured and the liquid strike on the compressor is avoided. Specifically, when
the multi-split air-conditioning system enters the pure heating mode, the discharge
superheat is obtained; and the total opening is calculated using a PI algorithm according
to the discharge superheat.
[0027] In step 104, the second electronic expansion valve is controlled according to the
target opening.
[0028] The second electronic expansion valve is controlled according to the calculated target
opening, such that the discharge superheat of the outdoor unit may be controlled.
[0029] With the method for controlling refrigerant distribution of a multi-split air-conditioning
system in embodiments of the present disclosure, when the multi-split air-conditioning
system enters the main cooling mode, first the second electronic expansion valve is
controlled to close, the opening of the electronic expansion valve corresponding to
the cooling indoor unit is controlled, and after the opening of the electronic expansion
valve corresponding to the cooling indoor unit reaches the maximum opening, the opening
of the second electronic expansion valve is controlled according to the total opening.
Therefore, the refrigerating capacity of the cooling indoor unit may be controlled
by controlling the refrigerant volume flowing into the cooling indoor unit so as to
ensure the cooling effect of the cooling indoor unit. Meanwhile, according to the
control of the total opening, the discharge superheat is effectively controlled, such
that the liquid strike on the compressor may be avoided, and the compressor is ensured
to operate safely and reliably.
[0030] In order to realize the method for controlling refrigerant distribution of a multi-split
air-conditioning system, a device for controlling refrigerant distribution of a multi-split
air-conditioning system is also provided in the present disclosure.
[0031] Fig. 3 is a block diagram of a device for controlling refrigerant distribution of
a multi-split air-conditioning system according to an embodiment of the present disclosure.
[0032] In an embodiment of the present disclosure, as shown in Fig. 2, the multi-split air-conditioning
system includes: a re-cooling system and a flow distributing device. The re-cooling
system includes a first heat exchanger, a second heat exchanger, a first electronic
expansion valve and a second electronic expansion valve.
[0033] As shown in Fig. 3, the device for controlling refrigerant distribution of a multi-split
air-conditioning system includes: a first control module 10, a second control module
20, a calculating module 30 and a third control module 40.
[0034] The first control module 10 is configured to control the second electronic expansion
valve to close when the multi-split air-conditioning system enters a main heating
mode. The second control module 20 is configured to control an electronic expansion
valve corresponding to a cooling indoor unit to perform an opening adjustment.
[0035] Generally, in a pure heating mode, the discharge superheat of an outdoor unit may
be controlled by controlling an opening of the second electronic expansion valve.
In the main heating mode, the discharge superheat of the outdoor unit and a refrigerant
volume flowing into the cooling indoor unit are controlled by controlling the opening
of the second electronic expansion valve and an opening of the electronic expansion
valve corresponding to the cooling indoor unit. Specifically, the opening of the second
electronic expansion valve and the opening of the electronic expansion valve corresponding
to the cooling indoor unit may be calculated according to the refrigerant volume required
by the cooling indoor unit for cooling. In an embodiment of the present disclosure,
in the main heating mode, since the electronic expansion valve corresponding to the
cooling indoor unit may also play the role of the second electronic expansion valve,
i.e. the refrigerant through the cooling indoor unit, which is satisfied with the
requirement of indoor cooling, will also obtain the superheat, such that the effect
of avoiding the liquid strike on the compressor may be satisfied. Therefore, the opening
of the electronic expansion valve corresponding to the cooling indoor unit may be
controlled by the second control module 20 preferentially in that mode, that is, before
controlling by the second control module 20 the electronic expansion valve corresponding
to the cooling indoor unit to perform the opening adjustment, the second electronic
expansion valve may be controlled to close by the first control module 10, and then
the control on the discharge superheat of the outdoor unit and the refrigerant volume
flowing into the cooling indoor unit may also be realized.
[0036] The calculating module 30 is configured to calculate a target opening of the second
electronic expansion valve according to a total opening and a maximum opening of the
electronic expansion valve corresponding to the cooling indoor unit when an opening
of the electronic expansion valve corresponding to the cooling indoor unit reaches
the maximum opening.
[0037] When the opening of the electronic expansion valve corresponding to the cooling indoor
unit reaches the maximum opening, the discharge superheat of the outdoor unit may
not be controlled. Then, the opening of the second electronic expansion valve needs
to be adjusted to control the discharge superheat of the outdoor unit. Specifically,
the target opening of the second electronic expansion valve is calculated by the calculating
module 30 based on a formula of:

where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI)
is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic
expansion valve corresponding to the cooling indoor unit, A
EV(cooling indoor) is a valve circulating area of the electronic expansion valve corresponding to the
cooling indoor unit, and A
EXV2 is a valve circulating area of the second electronic expansion valve.
[0038] The total opening may be obtained by calculating in the pure heating mode. When the
multi-split air-conditioning system enters the pure heating mode, the discharge superheat,
the discharge temperature and the returned-gas superheat of the outdoor unit are controlled
by the second electronic expansion valve, such that the reliability of the compressor
is ensured and the liquid strike on the compressor is avoided. Specifically, when
the multi-split air-conditioning system enters the pure heating mode, the discharge
superheat is obtained; and the total opening is calculated using a PI algorithm according
to the discharge superheat.
[0039] The third control module 40 is configured to control the second electronic expansion
valve according to the target opening.
[0040] The second electronic expansion valve may be controlled according to the calculated
target opening by the third control module 40, such that the discharge superheat of
the outdoor unit may be controlled.
[0041] With the device for controlling refrigerant distribution of a multi-split air-conditioning
system in embodiments of the present disclosure, when the multi-split air-conditioning
system enters the main cooling mode, first the second electronic expansion valve is
controlled to close, the opening of the electronic expansion valve corresponding to
the cooling indoor unit is controlled, and after the opening of the electronic expansion
valve corresponding to the cooling indoor unit reaches the maximum opening, the opening
of the second electronic expansion valve is controlled according to the total opening.
Therefore, the refrigerating capacity of the cooling indoor unit may be controlled
by controlling the refrigerant volume flowing into the cooling indoor unit so as to
ensure the cooling effect of the cooling indoor unit. Meanwhile, according to the
control of the total opening, the discharge superheat is effectively controlled, such
that the liquid strike on the compressor may be avoided, and the compressor is ensured
to operate safely and reliably.
[0042] In the specification, it is to be understood that terms such as "central," "longitudinal,"
"lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left,"
"right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise,"
"counterclockwise," "axial", "radial" and "circumference" should be construed to refer
to the orientation as then described or as shown in the drawings under discussion.
These relative terms are for convenience of description and do not require that the
present invention be constructed or operated in a particular orientation.
[0043] In addition, 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 comprise one or more of this feature. In the description of the present
invention, "a plurality of" means two or more than two, unless specified otherwise.
[0044] In the present invention, 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.
[0045] In the present invention, unless specified or limited otherwise, a structure in which
a first feature is "on" or "below" a second feature may include an embodiment in which
the first feature is in direct contact with the second feature, and may also include
an embodiment in which the first feature and the second feature are not in direct
contact with each other, but are contacted via an additional feature formed therebetween.
Furthermore, a first feature "on," "above," or "on top of" a second feature may include
an embodiment in which the first feature is right or obliquely "on," "above," or "on
top of" the second feature, or just means that the first feature is at a height higher
than that of the second feature; while a first feature "below," "under," or "on bottom
of" a second feature may include an embodiment in which the first feature is right
or obliquely "below," "under," or "on bottom of" the second feature, or just means
that the first feature is at a height lower than that of the second feature.
[0046] Reference throughout this specification to phrases like "an embodiment," "some embodiments,"
"one embodiment", "another example," "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. Thus, 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.
[0047] Although explanatory embodiments have been shown and described, it would be appreciated
by those skilled in the art that the above embodiments cannot be construed to limit
the present disclosure, and changes, alternatives, and modifications can be made in
the embodiments without departing from spirit, principles and scope of the present
disclosure.
1. A method for controlling refrigerant distribution of a multi-split air-conditioning
system, wherein, the multi-split air-conditioning system comprises a re-cooling system
and a flow distributing device, the re-cooling system comprises a first heat exchanger,
a second heat exchanger, a first electronic expansion valve and a second electronic
expansion valve, and the method comprises:
when the multi-split air-conditioning system enters a main heating mode, controlling
the second electronic expansion valve to close;
controlling an electronic expansion valve corresponding to a cooling indoor unit to
perform an opening adjustment;
when an opening of the electronic expansion valve corresponding to the cooling indoor
unit reaches a maximum opening, calculating a target opening of the second electronic
expansion valve according to a total opening and the maximum opening of the electronic
expansion valve corresponding to the cooling indoor unit; and
controlling the second electronic expansion valve according to the target opening.
2. The method according to claim 1, wherein, the total opening is obtained according
to following acts of:
when the multi-split air-conditioning system enters a pure heating mode, obtaining
a discharge superheat; and
calculating the total opening using a Proportional-Integral PI algorithm according
to the discharge superheat.
3. The method according to claim 1, wherein, the target opening of the second electronic
expansion valve is calculated by a formula of:

where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI)
is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic
expansion valve corresponding to the cooling indoor unit, A
EV(cooling indoor) is a valve circulating area of the electronic expansion valve corresponding to the
cooling indoor unit, and A
EXV2 is a valve circulating area of the second electronic expansion valve.
4. A device for controlling refrigerant distribution of a multi-split air-conditioning
system, wherein, the multi-split air-conditioning system comprises a re-cooling system
and a flow distributing device, the re-cooling system comprises a first heat exchanger,
a second heat exchanger, a first electronic expansion valve and a second electronic
expansion valve, and the device comprises:
a first control module, configured to control the second electronic expansion valve
to close when the multi-split air-conditioning system enters a main heating mode;
a second control module, configured to control an electronic expansion valve corresponding
to a cooling indoor unit to perform an opening adjustment;
a calculating module, configured to calculate a target opening of the second electronic
expansion valve according to a total opening and a maximum opening of the electronic
expansion valve corresponding to the cooling indoor unit when an opening of the electronic
expansion valve corresponding to the cooling indoor unit reaches the maximum opening;
and
a third control module, configured to control the second electronic expansion valve
according to the target opening.
5. The device according to claim 4, wherein, the total opening is obtained according
to following acts:
when the multi-split air-conditioning system enters a pure heating mode, obtaining
a discharge superheat; and
calculating the total opening using a PI algorithm according to the discharge superheat.
6. The device according to claim 4, wherein, the target opening of the second electronic
expansion valve is calculated by a formula of:

where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI)
is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic
expansion valve corresponding to the cooling indoor unit, A
EV(cooling indoor) is a valve circulating area of the electronic expansion valve corresponding to the
cooling indoor unit, and A
EXV2 is a valve circulating area of the second electronic expansion valve.