U.S. patent application number 16/651800 was filed with the patent office on 2020-07-30 for heat pump unit and the control method thereof.
The applicant listed for this patent is YORK (WUXI) AIR CONDITIONING AND REFRIGERATION CO., LTD. Johnson Controls Technology Company. Invention is credited to Hongsheng Chen, Qian Hu, Lue Lv.
Application Number | 20200240680 16/651800 |
Document ID | 20200240680 / US20200240680 |
Family ID | 1000004807473 |
Filed Date | 2020-07-30 |
Patent Application | download [pdf] |
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United States Patent
Application |
20200240680 |
Kind Code |
A1 |
Lv; Lue ; et al. |
July 30, 2020 |
HEAT PUMP UNIT AND THE CONTROL METHOD THEREOF
Abstract
A heat pump unit and methods for operating the heat pump unit
are provided. The heat pump unit includes a compressor (101), a
throttling device (107), a first heat exchanger (104), a second
heat exchanger (102), a third heat exchanger (103) and a
mid-pressure tank (110). The heat pump unit operates in multiple
run modes and switches between the run modes without shutdown. The
first heat exchanger or the second heat exchanger is capable of
acting as a condenser in the multiple run modes. When switching
from a pre-switching run mode to a post-switching run mode, a
control device determines whether to perform a pressure release
operation to the first heat exchanger or the second heat
exchanger.
Inventors: |
Lv; Lue; (Wuxi, CN) ;
Chen; Hongsheng; (Wuxi, CN) ; Hu; Qian; (Wuxi,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
YORK (WUXI) AIR CONDITIONING AND REFRIGERATION CO., LTD.
Johnson Controls Technology Company |
Wuxi
Auburn Hills |
MI |
CN
US |
|
|
Family ID: |
1000004807473 |
Appl. No.: |
16/651800 |
Filed: |
September 28, 2018 |
PCT Filed: |
September 28, 2018 |
PCT NO: |
PCT/IB2018/057535 |
371 Date: |
March 27, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 2600/2519 20130101;
F25B 13/00 20130101; F25B 41/062 20130101; F25B 2313/02741
20130101; F25B 47/02 20130101; F25B 41/04 20130101; F25B 2313/0231
20130101; F25B 2600/2513 20130101; F25B 1/00 20130101 |
International
Class: |
F25B 13/00 20060101
F25B013/00; F25B 41/04 20060101 F25B041/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 30, 2017 |
CN |
201710938025.X |
Sep 25, 2018 |
CN |
201811113760.8 |
Claims
1. A heat pump unit, comprising: a compressor having a suction end
and an exhaust end; a throttling device having an inlet end and an
outlet end; a first heat exchanger, a second heat exchanger and a
third heat exchanger, the first heat exchanger having a first port
and a second port, the second heat exchanger having a first port
and a second port, and the third heat exchanger having a first port
and a second port; and a mid-pressure tank being provided with a
mid-pressure tank first inlet; wherein the first port of the first
heat exchanger and the first port of the second heat exchanger are
controllably fluidly connected to the suction end of the
compressor, and controllably fluidly connected to the exhaust end
of the compressor, and wherein the first port of the third heat
exchanger is fluidly connected to the suction end of the
compressor; and wherein the second port of the first heat exchanger
and the second port of the second heat exchanger are controllably
fluidly connected to the inlet end of the throttling device,
controllably fluidly connected to the outlet end of the throttling
device, and controllably fluidly connected to the mid-pressure tank
first inlet, and wherein the second port of the third heat
exchanger is controllably fluidly connected to the outlet end of
the throttling device.
2. The heat pump unit of claim 1, further comprising: a four-way
valve having a first interface, a second interface, a third
interface, and a fourth interface; wherein the first port of the
first heat exchanger is connected to the second interface of the
four-way valve, the first port of the second heat exchanger is
connected to the fourth interface of the four-way valve, the
suction end of the compressor is connected to the first interface
of the four-way valve and the exhaust end of the compressor is
connected to the third interface of the four-way valve.
3. The heat pump unit of claim 2, further comprising: a
throttling-device-inlet-side control valve group including a first
valve and a second valve, wherein the second port of the first heat
exchanger and the second port of the second heat exchanger are
controllably fluidly connected to the inlet end of the throttling
device via the first valve and the second valve of the
throttling-device-inlet-side control valve group, respectively; and
a throttling-device-outlet-side control valve group including a
first valve, a second valve and a third valve, wherein the second
port of the first heat exchanger and the second port of the second
heat exchanger are controllably fluidly connected to the outlet end
of the throttling device via the first valve and the second valve
of the throttling-device-outlet-side control valve group,
respectively, and wherein the second port of the third heat
exchanger is controllably fluidly connected to the outlet end of
the throttling device via the third valve of the
throttling-device-outlet-side control valve group.
4. The heat pump unit of claim 3, wherein: the mid-pressure tank is
provided with a mid-pressure tank first outlet, the mid-pressure
tank first outlet is controllably fluidly connected to the outlet
end of the throttling device; and the heat pump unit further
comprises: a mid-pressure tank first inlet control valve group
comprising a first valve and a second valve, wherein the second
port of the first heat exchanger and the second port of the second
heat exchanger are controllably fluidly connected to the
mid-pressure tank first inlet via the first valve and the second
valve of the mid-pressure tank first inlet control valve group,
respectively; and a mid-pressure tank first outlet control valve
wherein the mid-pressure tank first outlet is controllably fluidly
connected to the outlet end of the throttling device via the
mid-pressure tank first outlet control valve.
5. The heat pump unit of claim 4, further comprising: a
mid-pressure tank pressure-increasing control valve and a
mid-pressure tank pressure-reducing control valve; wherein the
mid-pressure tank is provided with a mid-pressure tank second inlet
and a mid-pressure tank second outlet; and wherein the mid-pressure
tank second inlet is connected to the fluid path between the
exhaust end of the compressor and the four-way valve via the
mid-pressure tank pressure-increasing control valve, and the
mid-pressure tank second outlet is connected to the suction end of
the compressor via the mid-pressure tank pressure-reducing control
valve.
6. The heat pump unit of claim 4, wherein the mid-pressure tank
first inlet control valve group further comprises a first one-way
valve and a second one-way valve, wherein the first one-way valve
is connected between the first valve of the mid-pressure tank first
inlet control valve group and the mid-pressure tank first inlet,
and the second one-way valve is connected between the second valve
of the mid-pressure tank first inlet control valve group and the
mid-pressure tank first inlet.
7. The heat pump unit of claim 5, wherein the first valve and the
second valve of the throttling-device-inlet-side control valve
group are one-way valves.
8. The heat pump unit of claim 7, further comprising a control
device wherein the four-way valve the throttling-device-outlet-side
control valve group, the mid-pressure tank first inlet control
valve group, the mid-pressure tank first outlet control valve, the
mid-pressure tank pressure-increasing control valve and the
mid-pressure tank pressure-reducing control valve are connected to
and controlled by the control device.
9. The heat pump unit of claim 1, wherein the first heat exchanger
and the third heat exchanger are connected to a first water supply
and return pipe and a second water supply and return pipe,
respectively.
10. The heat pump unit of claim 1, wherein: the heat pump unit is
configured such that said heat pump unit is capable of running in
multiple modes and being switched between the multiple modes by
controlling the flow path of the refrigerant through the
compressor, the throttling device, the first heat exchanger, the
second heat exchanger and the third heat exchanger; and the
high-pressure refrigerant from any of the first heat exchanger and
the second heat exchanger which needs pressure release at the time
of mode switching can be received by the mid-pressure tank.
11. A method for controlling a heat pump unit, the heat pump unit
comprising a compressor, a throttling device, a first heat
exchanger, a second heat exchanger, a third heat exchanger, and a
mid-pressure tank wherein the heat pump unit is capable of running
in multiple modes and the first heat exchanger or the second heat
exchanger is capable of acting as a condenser in the multiple
modes, the method comprising: determining whether it is desired to
perform a pressure release operation to the first heat exchanger or
the second heat exchanger when it is desired to switch the run mode
of the heat pump unit from a pre-switching run mode to a
post-switching run mode; and maintaining the pre-switching run mode
and performing a first operation responsive to a determination that
it is desired to perform the pressure release operation to the
first heat exchanger, wherein the first operation comprises fluidly
connecting the first heat exchanger to a first inlet of the
mid-pressure tank so as to discharge the refrigerant from the first
heat exchanger to the mid-pressure tank; or maintaining the
pre-switching run mode and performing a second operation responsive
to a determination that it is desired to perform the pressure
release operation to the second heat exchanger, wherein the second
operation comprises fluidly connecting the second heat exchanger to
the first inlet of the mid-pressure tank so as to discharge the
refrigerant from the second heat exchanger to the mid-pressure
tank.
12. The method of claim 11, further comprising: performing a third
operation, wherein the third operation comprises disconnecting the
first heat exchanger from the first inlet of the mid-pressure tank
after a first predetermined amount of time has elapsed since the
first operation is performed; or performing a fourth operation,
wherein the fourth operation comprises disconnecting the second
heat exchanger from the first inlet of the mid-pressure tank after
a second predetermined amount of time has elapsed since the second
operation is performed.
13. The method of claim 12, further comprising starting the
post-switching run mode and ending the pre-switching run mode after
the third operation or the fourth operation is performed.
14. The method of claim 11, further comprising: Performing a fifth
operation responsive to a determination that it is desired to
supplement refrigerant to the refrigerant circulation loop of the
post-switching run mode after the post-switching run mode is
started, wherein the fifth operation comprises fluidly connecting a
first outlet of the mid-pressure tank to an outlet end of the
throttling device.
15. The method of claim 14, further comprising: fluidly connecting
a second inlet of the mid-pressure tank to an exhaust end of the
compressor so as to increase the pressure in the mid-pressure tank
responsive to a determination that the pressure in the mid-pressure
tank is below a first predetermined pressure value during the fifth
operation.
16. The method of claim 11, further comprising: fluidly connecting
a second outlet of the mid-pressure tank to a suction end of the
compressor so as to reduce the pressure in the mid-pressure tank
responsive to a determination that the pressure in the mid-pressure
tank is above a second predetermined pressure value during the
first operation or the second operation.
17. The method of claim 11, wherein the step of determining whether
it is desired to perform a pressure release operation to the first
heat exchanger or the second heat exchanger comprises: determining
that it is desired to perform the pressure release operation to the
first heat exchanger or the second heat exchanger when the first
heat exchanger or the second heat exchanger acting as a condenser
in the pre-switching run mode does not act as a condenser in the
post-switching run mode.
18. The method of claim 17, wherein: the multiple modes comprise a
cooling only mode, a heating only mode, a cooling plus heating
mode, and a defrosting mode; and the first heat exchanger and the
third heat exchanger are connected to a first water supply and
return pipe and a second water supply and return pipe,
respectively.
19. The method of claim 18, wherein: the compressor, the throttling
device, the second heat exchanger and the third heat exchanger are
in a refrigerant circulation loop when the heat pump unit runs in
the cooling only mode, wherein the second heat exchanger acts as a
condenser in the cooling only mode; the compressor, the throttling
device, the first heat exchanger and the second heat exchanger are
in a refrigerant circulation loop when the heat pump unit runs in
the heating only mode, wherein the first heat exchanger acts as a
condenser in the heating only mode; the compressor, the throttling
device, the first heat exchanger and the third heat exchanger are
in a refrigerant circulation loop when the heat pump unit runs in
the cooling plus heating mode, wherein the first heat exchanger
acts as a condenser in the cooling plus heating mode; and the
compressor, the throttling device, the first heat exchanger and the
second heat exchanger are in a refrigerant circulation loop when
the heat pump unit runs in the defrosting mode, wherein the second
heat exchanger acts as a condenser in the defrosting mode.
20. The method of claim 19, wherein determining whether it is
desired to perform a pressure release operation to the first heat
exchanger or the second heat exchanger comprises: determining that
it is desired to perform the pressure release operation to the
second heat exchanger when the pre-switching run mode is the
cooling only mode while the post-switching run mode is the heating
only mode or the cooling plus heating mode; determining that it is
desired to perform the pressure release operation to the first heat
exchanger when the pre-switching run mode is the heating only mode
while the post-switching run mode is the cooling only mode or the
defrosting mode; determining that it is desired to perform the
pressure release operation to the first heat exchanger when the
pre-switching run mode is the cooling plus heating mode while the
post-switching run mode is the cooling only mode; or determining
that it is desired to perform the pressure release operation to the
second heat exchanger when the pre-switching run mode is the
defrosting mode while the post-switching run mode is the heating
only mode.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This application claims the benefit of and priority to
Chinese Patent Application No. 201710938025X entitled "Heat Pump
Unit and The Control Method Thereof," filed Sep. 30, 2017, and
Chinese Patent Application No. 2018111137608 entitled "Heat Pump
Unit and The Method for Control the Heat Pump Unit," filed Sep. 25,
2018, which are hereby incorporated by reference in its
entirety.
TECHNICAL FIELD
[0002] The present application relates to the field of heat pumps,
and in particular relates to a heat pump unit (or a heat pump
system) applicable to the application scenario where there are
demands on both cold and heat, and the control method thereof.
BACKGROUND
[0003] A heat pump unit comprises a compressor, a throttling device
and at least two heat exchangers, the compressor, the throttling
device and the at least two heat exchangers form a refrigerant
circulation system, and heat is exchanged with the work end (such
as water) via the heat exchangers so that heat of condensation can
be utilized for heat recovery heating while cooling the working
end. The heat pump unit is capable of running in multiple modes and
being switched between the multiple modes.
[0004] When the running mode of the heat pump unit is switched, it
may be necessary to change the flow direction of the refrigerant in
the circulation system. In this case, the compressor may first be
stopped, the pressure of the heat exchanger (i.e., the heat
exchanger acting as a condenser) on the high-pressure side of the
circulation system is released after a period of time, and then the
heat exchanger is switched to the low-pressure side. The inventors
of the present disclosure found that the existing heat pump unit
cannot be switched between the working modes in time. In addition,
the pressure in the circulation system fluctuates greatly and
impacts the pipelines greatly at the time of mode switching.
Therefore, the noise and vibration levels are so high that the
stability and the level of comfort associated with the heat pump
unit is reduced. Especially when defrosting and drainage are
necessary for the heat exchangers, the shutdown and pressure
release time even exceeds the defrosting and drainage time such
that the working efficiency of the heat pump unit is greatly
affected.
[0005] Furthermore, it may be necessary to provide a plurality of
four-way reversing valves or three-way reversing valves in a
multifunctional heat pump unit so as to change directions for the
compressor and the throttling device. Thus, the connection
structures of the pipelines are complicated, the energy efficiency
of the system is low, the risk of a refrigerant leakage is very
high, and a complicated control method may be required to switch
and regulate multiple functions.
[0006] To solve the above-mentioned problems, at least one
objective of the present application is to provide a heat pump unit
having multiple functions and performing a free switching between
the multiple functions conveniently, smoothly and efficiently.
SUMMARY
[0007] One implementation of the present disclosure is a heat pump
unit. The heat pump unit includes a compressor having a suction end
and an exhaust end; a throttling device having an inlet end and an
outlet end; a first heat exchanger, a second heat exchanger, and a
third heat exchanger, the first heat exchanger having a first port
and a second port, the second heat exchanger having a first port
and a second port, and the third heat exchanger having a first port
and a second port; and a mid-pressure tank being provided with a
mid-pressure tank first inlet. The first port of the first heat
exchanger and the first port of the second heat exchanger are
controllably fluidly connected to the suction end of the compressor
and controllably fluidly connected to the exhaust end of the
compressor. The first port of the third heat exchanger is fluidly
connected to the suction end of the compressor. The second port of
the first heat exchanger and the second port of the second heat
exchanger are controllably fluidly connected to the inlet end of
the throttling device, controllably fluidly connected to the outlet
end of the throttling device, and controllably fluidly connected to
the mid-pressure tank first inlet. The second port of the third
heat exchanger is controllably fluidly connected to the outlet end
of the throttling device.
[0008] The heat pump unit can further include a four-way valve
having a first interface, a second interface, a third interface,
and a fourth interface. The first port of the first heat exchanger
is connected to the second interface of the four-way valve, the
first port of the second heat exchanger is connected to the fourth
interface of the four-way valve, the suction end of the compressor
is connected to the first interface of the four-way valve, and the
exhaust end of the compressor is connected to the third interface
of the four-way valve.
[0009] The heat pump unit can further include a
throttling-device-inlet-side control valve group including a first
valve and a second valve. The second port of the first heat
exchanger and the second port of the second heat exchanger can be
controllably fluidly connected to the inlet end of the throttling
device via the first valve and the second valve of the
throttling-device-inlet-side control valve group, respectively. The
heat pump unit can further comprise a throttling-device-outlet-side
control valve group including a first valve, a second valve and a
third valve. The second port of the first heat exchanger and the
second port of the second heat exchanger can be controllably
fluidly connected to the outlet end of the throttling device via
the first valve and the a second valve of the
throttling-device-outlet-side control valve group, respectively.
The second port of the third heat exchanger can be controllably
fluidly connected to the outlet end of the throttling device via
the third valve of the throttling-device-outlet-side control valve
group.
[0010] The mid-pressure tank can be provided with a mid-pressure
first outlet. The mid-pressure first outlet can be controllably
fluidly connected to the outlet end of the throttling device. The
heat pump unit can further comprise a mid-pressure tank first inlet
control valve group including a first valve and a second valve. The
second port of the first heat exchanger and the second port of the
second heat exchanger can be controllably fluidly connected to the
mid-pressure tank first inlet via the first valve and the second
valve of the mid-pressure tank first inlet control valve group,
respectively. The heat pump unit can further comprise a
mid-pressure tank first outlet control. The mid-pressure first
outlet can be controllably fluidly connected to the outlet end of
the throttling device via the mid-pressure tank first outlet
control valve.
[0011] The heat pump unit can further include a mid-pressure tank
pressure-increasing control valve and a mid-pressure tank
pressure-reducing control valve. The mid-pressure tank can be
provided with a mid-pressure tank second inlet and a mid-pressure
tank second outlet. The mid-pressure tank second inlet can be
connected to the fluid path between the exhaust end of the
compressor and the four-way valve via the mid-pressure tank
pressure-increasing control valve. The mid-pressure tank second
outlet can be connected to the suction end of the compressor via
the mid-pressure tank pressure-reducing control valve.
[0012] The mid-pressure tank first inlet control valve group
further can include a first one-way valve and a second one-way
valve. The first one-way valve can be connected between the first
valve of the mid-pressure tank first inlet control valve group and
the mid-pressure tank first inlet. The second one-way valve can be
connected between the second valve of the mid-pressure tank first
inlet control valve group and the mid-pressure tank first
inlet.
[0013] The first valve and the second valve of the
throttling-device-inlet-side control valve group can be one-way
valves. The first heat exchanger and the third heat exchanger can
be connected to a first water supply and return pipe and a second
water supply and return pipe, respectively.
[0014] The heat pump unit can further include a control device. The
four-way valve, the throttling-device-outlet-side control valve
group, the mid-pressure tank first inlet control valve group, the
mid-pressure tank first outlet control valve, the mid-pressure tank
pressure-increasing control valve and the mid-pressure tank
pressure-reducing control valve can be connected to and controlled
by the control device.
[0015] The heat pump unit can be configured such that the heat pump
unit can run in multiple modes and can be switched between the
multiple modes by controlling the flow path of the refrigerant
through the compressor, the throttling device and the first heat
exchanger, the second heat exchanger and the third heat exchanger.
High-pressure refrigerant from any of the first heat exchanger and
the second heat exchanger which need pressure releasing at the time
of mode switching can be received by the mid-pressure tank.
[0016] Another implementation of the present disclosure is a method
for controlling a heat pump unit. The heat pump unit includes a
compressor, a throttling device, a first heat exchanger, a second
heat exchanger, a third heat exchanger, and a mid-pressure tank.
The heat pump unit is capable of running in multiple modes and the
first heat exchanger or the second heat exchanger is capable of
acting as a condenser in the multiple modes. The method includes
determining whether it is desired to perform a pressure release
operation to the first heat exchanger or the second heat exchanger
when it is desired to switch the run mode of the heat pump unit
from a pre-switching run mode to a post-switching run mode. The
method further includes maintaining the pre-switching run mode and
performing Operation 1 responsive to a determination that it is
desired to perform the pressure release operation to the first heat
exchanger, wherein Operation 1 comprises fluidly connecting the
first heat exchanger to a first inlet of the mid-pressure tank so
as to discharge the refrigerant from the first heat exchanger to
the mid-pressure tank; or maintaining the pre-switching run mode
and performing Operation 2 responsive to a determination that it is
desired to perform the pressure release operation to the second
heat exchanger, wherein Operation 1 comprises fluidly connecting
the second heat exchanger to the first inlet of the mid-pressure
tank so as to discharge the refrigerant from the second heat
exchanger to the mid-pressure tank.
[0017] The method can further include performing Operation 3,
wherein Operation 3 comprises disconnecting the first heat
exchanger from the first inlet of the mid-pressure tank after a
first predetermined amount of time has elapsed since Operation 1 is
performed. The method can further include performing Operation 4,
wherein Operation 4 comprises disconnecting the second heat
exchanger from the first inlet of the mid-pressure tank after a
second predetermined amount of time has elapsed since Operation 2
is performed.
[0018] The method can further include starting the post-switching
run mode and ending the pre-switching run mode after Operation 3 or
Operation 4 is performed.
[0019] The method can further include performing Operation 5
responsive to a determination that it is desired to supplement
refrigerant to the refrigerant circulation loop of the
post-switching run mode after the post-switching run mode is
started, wherein Operation 5 comprises fluidly connecting a first
outlet of the mid-pressure tank to an outlet end of the throttling
device.
[0020] The method can further include fluidly connecting a second
inlet of the mid-pressure tank to an exhaust end of the compressor
so as to increase the pressure in the mid-pressure tank responsive
to a determination that the pressure in the mid-pressure tank is
below a first predetermined pressure value during performing
Operation 5.
[0021] The method can further include fluidly connecting a second
outlet of the mid-pressure tank to a suction end of the compressor
so as to reduce the pressure in the mid-pressure tank responsive to
a determination that the pressure in the mid-pressure tank is above
a second predetermined pressure value during Operation 1 or
Operation 2.
[0022] The step of determining whether it is desired to perform a
pressure release operation to the first heat exchanger or the
second heat exchanger can include determining that it is desired to
perform the pressure release operation to the first heat exchanger
or the second heat exchanger when the first heat exchanger or the
second heat exchanger acting as a condenser in the pre-switching
run mode does not act as a condenser in the post-switching run
mode.
[0023] The multiple modes can include a cooling only mode, a
heating only mode, a cooling plus heating mode, and a defrosting
mode. The first heat exchanger and the third heat exchanger can be
connected to a first water supply and return pipe and a second
water supply and return pipe, respectively.
[0024] The compressor, the throttling device, the second heat
exchanger and the third heat exchanger can be in a refrigerant
circulation loop when the heat pump unit runs in the cooling only
mode, wherein the second heat exchanger acts as a condenser in the
cooling only mode. The compressor, the throttling device, the first
heat exchanger and the second heat exchanger can be in a
refrigerant circulation loop when the heat pump unit runs in the
heating only mode, wherein the first heat exchanger acts as a
condenser in the heating only mode. The compressor, the throttling
device, the first heat exchanger and the third heat exchanger can
be in a refrigerant circulation loop when the heat pump unit runs
in the cooling plus heating mode, wherein the first heat exchanger
acts as a condenser in the cooling plus heating mode. The
compressor, the throttling device, the first heat exchanger and the
second heat exchanger can be in a refrigerant circulation loop when
the heat pump unit runs in the defrosting mode, wherein the second
heat exchanger acts as a condenser in the defrosting mode.
[0025] The step of determining whether it is desired to perform a
pressure release operation to the first heat exchanger or the
second heat exchanger can include determining that it is desired to
perform the pressure release operation to the second heat exchanger
if the pre-switching run mode is the cooling only mode while the
post-switching run mode is the heating only mode or the cooling
plus heating mode; determining that it is desired to perform the
pressure release operation to the first heat exchanger when the
pre-switching run mode is the heating only mode while the
post-switching run mode is the cooling only mode or the defrosting
mode; determining that it is desired to perform the pressure
release operation to the first heat exchanger when the
pre-switching run mode is the cooling plus heating mode while the
post-switching run mode is the cooling only mode; or determining
that it is desired to perform the pressure release operation to the
second heat exchanger when the pre-switching run mode is the
defrosting mode while the post-switching run mode is the heating
only mode.
[0026] By using the mid-pressure tank to receive the high-pressure
refrigerant from the heat exchanger, the heat pump unit of the
present disclosure can be capable of switching between multiple
modes in time, without any shutdown. Thus, the time waiting for the
heat exchanger to release the pressure is reduced and the switching
efficiency can be improved. Therefore, not only the heat pump unit
of the present disclosure can realize multiple modes, such as
cooling only, heating only, cooling plus heating, and defrosting,
but also the working state of the heat pump unit can flexibly be
regulated according to the requirements for the working condition.
Thus, the cooling capacity and heating capacity of the heat pump
unit can be regulated to satisfy the requirements for the working
condition. In addition, the pipeline connections of the heat pump
unit of the present application can be simple, no gas-liquid
separator or liquid storage needs to be provided separately, the
structure is compact, the risk of a refrigerant leakage is lowered,
and the reliability of the heat pump unit is improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a block diagram of a heat pump unit, according to
an embodiment of the present disclosure;
[0028] FIG. 2A is a block diagram of a control device for the heat
pump unit of FIG. 1, according to some embodiments;
[0029] FIG. 2B is a block diagram of a control device for the heat
pump unit of FIG. 1, according to some embodiments;
[0030] FIG. 2C is a block diagram of a control device for the heat
pump unit of FIG. 1, according to some embodiments;
[0031] FIG. 3A is a block diagram illustrating the refrigerant
circulation loops of the heat pump unit of FIG. 1 operating in the
cooling only mode, according to some embodiments;
[0032] FIG. 3B is a block diagram illustrating the refrigerant
circulation loops of the heat pump unit of FIG. 1 operating in the
heating only mode, according to some embodiments;
[0033] FIG. 3C is a block diagram illustrating the refrigerant
circulation loops of the heat pump unit of FIG. 1 operating in the
cooling plus heating mode, according to some embodiments;
[0034] FIG. 3D is a block diagram illustrating the refrigerant
circulation loops of the heat pump unit of FIG. 1 operating in the
defrosting mode, according to some embodiments;
[0035] FIG. 4 is a process flow diagram illustrating a method of
switching the run mode of the heat pump unit of FIG. 1, according
to some embodiments;
[0036] FIG. 5A is a block diagram illustrating the flow path of
refrigerant when switching the run mode of the heat pump unit of
FIG. 1 from a cooling mode to a cooling plus heating mode,
according to some embodiments;
[0037] FIG. 5B is a block diagram illustrating the flow path of
refrigerant when performing a refrigerant supplement operation to
the refrigerant circulation loop of the heat pump unit of FIG. 1
running in the cooling plus heating mode, according to some
embodiments;
[0038] FIG. 6 is a block diagram of a heat pump unit according to
another embodiment of the present disclosure.
DETAILED DESCRIPTION
[0039] The following will describe various specific implementation
modes of the present application by reference to the drawings which
constitute a part of the present description. It should be
understood that although the terms indicating directions, such as
"before", "behind", "above", "below", "left", and "right" are used
to describe various exemplified structural parts and components in
the present application, these terms are just used for the
convenience of illustrations and are determined based on the
exemplified directions in the drawings. Since the embodiments
disclosed in the present application can be set in different
directions, these terms indicating directions are only used as
illustrations, instead of restrictions.
[0040] FIG. 1 is a block diagram of a heat pump unit according to
an embodiment of the present disclosure. As shown in FIG. 1, the
heat pump unit of the present disclosure comprises a compressor
101, a throttling device 107, a first heat exchanger 104, a second
heat exchanger 102, a third heat exchanger 103, a mid-pressure tank
110, a four-way valve 120, and a plurality of other valves that
will be introduced below. The connecting lines among the components
(including the compressor 101, the throttling device 107, the first
heat exchanger 104, the second heat exchanger 102, the third heat
exchanger 103, the mid-pressure tank 110, the four-way valve 120,
and the plurality of other valves) of FIG. 1 represents connecting
pipelines. The compressor 101 has a suction end 106 and an exhaust
end 105, and the suction end 106 and the exhaust end 105 are
respectively connected to the four-way valve 120. The compressor
101 allows one-way flow of fluid from the suction end 106 to the
exhaust end 105 thereof. The throttling device 107 has an inlet end
108 and an outlet end 109, and allows one-way flow of fluid from
the inlet end 108 to the outlet end 109 thereof. In other
embodiments, the four-way valve 120 can be replaced by other valves
or valve groups. The four-way valve 120 shown in FIG. 1 has four
interfaces, including a first interface 120.1, a second interface
120.2, a third interface 120.3, and a fourth interface 120.4. The
first interface 120.1 is connected to the suction end 106 of the
compressor 101, the third interface 120.3 is connected to the
exhaust end 105 of the compressor 101, the second interface 120.2
is connected to the first heat exchanger 104, and the fourth
interface 120.4 is connected to the second heat exchanger 102.
[0041] If the third interface 120.3 of the four-way valve 120 is
connected to the second interface 120.2 and the first interface
120.1 is connected to the fourth interface 120.4, the exhaust end
105 of the compressor 101 is fluidly connected to the first heat
exchanger 104 and the suction end 106 of the compressor 101 is
fluidly connected to the second heat exchanger 102. In this way,
the first heat exchanger 104 is capable of acting as a condenser
located on the high-pressure side of the heat pump unit, while the
second heat exchanger 102 is capable of being located on the
low-pressure side of the heat pump unit.
[0042] If the third interface 120.3 of the four-way valve 120 is
connected to the fourth interface 120.4 and the first interface
120.1 is connected to the second interface 120.2, the exhaust end
105 of the compressor 101 is fluidly connected to the second heat
exchanger 102 and the suction end 106 of the compressor 101 is
fluidly connected to the first heat exchanger 104. In this way, the
second heat exchanger 102 is capable of acting as a condenser
located on the high-pressure side of the heat pump unit, while the
first heat exchanger 104 is capable of being located on the
low-pressure side of the heat pump unit.
[0043] As shown in FIG. 1, the heat pump unit further comprises a
third heat exchanger 103, and the third heat exchanger 103 is
fluidly connected to the suction end 106 of the compressor 101.
Therefore, the third heat exchanger 103 may be located on the
low-pressure side of the heat pump unit and may not act as a
condenser.
[0044] Still as shown in FIG. 1, the first heat exchanger 104, the
second heat exchanger 102 and the third heat exchanger 103 each
have at least two ports, wherein the first port 116.1 of the first
heat exchanger 104 and the first port 121.1 of the second heat
exchanger 102 are configured to connect to the four-way valve 120,
and the first port 123.1 of the third heat exchanger 103 is
configured to connect to the suction end 106 of the compressor 101.
The heat pump unit further comprises a throttling-device-inlet-side
control valve group 115.1,115.2 and a throttling-device-outlet-side
control valve group 118.1,118.2,118.3.
[0045] The first heat exchanger 104 further has a second port
116.2. The second port 116.2 is fluidly connected to the inlet end
108 of the throttling device 107 via a first valve 115.1 of the
throttling-device-inlet-side control valve group and the second
port 116.2 is fluidly connected to the outlet end 109 of the
throttling device 107 via a first valve 118.1 of the
throttling-device-outlet-side control valve group, so that the
second port 116.2 can act as not only the inlet of the first heat
exchanger 104 to receive the refrigerant flowing out of the outlet
end 109 of the throttling device 107, but also the outlet of the
first heat exchanger 104 to supply the refrigerant to the inlet end
108 of the throttling device 107. Therefore, the first heat
exchanger 104 allows controllable two-way flow of fluid from the
first port 116.1 to the second port 116.2 thereof or from the
second port 116.2 to the first port 116.1 thereof.
[0046] Similar to the first heat exchanger 104, the second heat
exchanger 102 also has a second port 121.2. The second port 121.2
is fluidly connected to the inlet end 108 of the throttling device
107 via a second valve 115.2 of the throttling-device-inlet-side
control valve group and is fluidly connected to the outlet end 109
of the throttling device 107 via a second valve 118.2 of the
throttling-device-outlet-side control valve group. Therefore, the
second heat exchanger 102 allows controllable two-way flow of fluid
from the first port 121.1 to the second port 121.2 thereof or from
the second port 121.2 to the first port 121.1 thereof.
[0047] The third heat exchanger 103 also has a second port 123.2,
but the second port 123.2 of the third heat exchanger 103 is only
fluidly connected to the outlet end 109 of the throttling device
107 via a third valve 118.3 of the throttling-device-outlet-side
control valve group.
[0048] In the embodiment shown in FIG. 1, the throttling device 107
is an expansion valve, the high-pressure refrigerant goes from the
inlet end 108 into the expansion valve 107 and is changed into a
low-pressure refrigerant, and the low-pressure refrigerant is then
discharged from the outlet end 109. Thus, in order to let the
refrigerant in the first heat exchanger 104 and the second heat
exchanger 102 controllably flow to the inlet end 108 of the
throttling device 107, the first valve 115.1 and the second valve
115.2 of the throttling-device-inlet-side control valve group can
be solenoid valves or one-way valves. For example, the first valve
115.1 and the second valve 115.2 of the
throttling-device-inlet-side control valve group in the embodiment
shown in FIG. 1 are one-way valves so that much more cost can be
saved. The refrigerant in the first heat exchanger 104 can flow to
the inlet end 108 of the throttling device 107 when the one-way
valve 115.1 is opened, and the refrigerant in the second heat
exchanger 102 can flow to the inlet end 108 of the throttling
device 107 when the one-way valve 115.2 is opened.
[0049] The one-way valves are automatically opened and closed due
to the pressure difference across the one-way valves without the
need of being controlled by the control device 230 as shown in FIG.
2A. However, according to the present disclosure, the first valve
115.1 and the second valve 115.2 of the
throttling-device-inlet-side control valve group can also be
solenoid valves which are connected to and controlled by the
control device 230 as shown in FIG. 2A. The first valve 118.1, the
second valve 118.2 and the third valve 118.3 of the
throttling-device-outlet-side control valve group can be solenoid
valves, so that the refrigerant flowing out of the outlet end 109
of the throttling device 107 can controllably flow into the
required heat exchanger(s). For example, if the first valve 118.1
of the throttling-device-outlet-side control valve group is opened
and the second valve 118.2 and the third valve 118.3 of the
throttling-device-outlet-side control valve group are closed, the
refrigerant flowing out of the outlet end 109 of the throttling
device 107 can flow into the first heat exchanger 104.
[0050] The first heat exchanger 104, the second heat exchanger 102
and the third heat exchanger 103 as mentioned above can be
different types of heat exchangers, for example, air heat
exchangers exchanging heat with air or waterside heat exchangers
exchanging heat with water. As an exemplified embodiment, the
second heat exchanger 102 is an air heat exchanger not connected to
the working end, while the first heat exchanger 104 and the third
heat exchanger 103 are waterside heat exchangers and are
respectively connected to first water supply and return pipe 111.1
and second water supply and return pipe 111.2 so that the heat
exchangers can supply the heating load or cooling load required on
the user side when exchanging heat. As another example, the heat
pump unit of the present application can include more than three
heat exchangers.
[0051] Still as shown in FIG. 1, the heat pump unit further
comprises a mid-pressure tank 110. The mid-pressure tank 110 is a
container used to store the refrigerant. The refrigerant can be a
refrigerant liquid, or a refrigerant gas, or a mixture of the gas
and liquid of a refrigerant. The mid-pressure tank 110 has a
mid-pressure tank first inlet 112 and a mid-pressure tank first
outlet 128, wherein the mid-pressure tank first inlet 112 is
fluidly connected to the heat exchangers (i.e., the first heat
exchanger 104 and the second heat exchanger 102) which are capable
of acting as condensers via a mid-pressure tank first inlet control
valve group 113.1, 113.2.
[0052] In the embodiment shown in FIG. 1, the mid-pressure tank
first inlet 112 is respectively fluidly connected to the second
port 116.2 of first heat exchanger 104 and the second port 121.2 of
the second heat exchanger 102 via a first valve 113.1 and a second
valve 113.2 of the mid-pressure tank first inlet control valve
group. As an example, the mid-pressure tank first inlet 112 is
connected to the fluid path between the first valve 115.1 of the
throttling-device-inlet-side control valve group and the inlet end
108 of the throttling device 107 via the first valve 113.1 of the
mid-pressure tank first inlet control valve group and is connected
to the fluid path between the second valve 115.2 of the
throttling-device-inlet-side control valve group and the inlet end
108 of the throttling device 107 via the second valve 113.2 of the
mid-pressure tank first inlet control valve group. Thus, the
high-pressure refrigerant in the first heat exchanger 104 and the
second heat exchanger 102 can flow into the mid-pressure tank 110
by controlling the throttling-device-inlet-side control valve group
115.1, 115.2 and the mid-pressure tank first inlet control valve
group 113.1, 113.2. As another example, there can be a plurality of
shown mid-pressure tank first inlets 112 and each inlet is
respectively fluidly connected to the heat exchanger which is
capable of acting as a condenser via its corresponding first inlet
control valve. In another embodiment, the mid-pressure tank first
inlet control valve group is provided with only one valve through
which the mid-pressure tank first inlet 112 is connected to the
inlet end 108 of the throttling device 107.
[0053] In the mid-pressure tank 110 shown in FIG. 1, the
mid-pressure tank first outlet 128 is fluidly connected to the
low-pressure side of the running heat pump unit via a mid-pressure
tank first outlet control valve 114, and thus the refrigerant in
the mid-pressure tank 110 can flow into the refrigerant circulation
loop to supplement refrigerant to the refrigerant circulation loop.
The mid-pressure tank first outlet 128 is fluidly connected to the
second port 116.2 of the first heat exchanger 104, the second port
121.2 of the second heat exchanger 102, and the second port 123.2
of the third heat exchanger 103 via the mid-pressure tank first
outlet control valve 114. To improve the running stability of the
heat pump unit, the mid-pressure tank first outlet control valve
114 can be an expansion valve to ensure that the refrigerant
flowing out of the mid-pressure tank first outlet 128 can be
changed into a low-pressure refrigerant and then the low-pressure
refrigerant flows into the low-pressure side of the running heat
pump unit. As an example, the mid-pressure tank first outlet 128 is
fluidly connected to the outlet end 109 of the throttling device
107 via the mid-pressure tank first outlet control valve 114. The
mid-pressure tank first inlet 112 and the mid-pressure tank first
outlet 128 are mainly used for delivery of the refrigerant liquid
such that they are provided at the bottom of the mid-pressure tank
110.
[0054] The heat pump unit further comprises a mid-pressure tank
pressure-increasing control valve 135 and a mid-pressure tank
pressure-reducing control valve 136. The mid-pressure tank 110 is
further provided with a mid-pressure tank second inlet 181 and a
mid-pressure tank second outlet 182. As an example, the
mid-pressure tank second inlet 181 is connected to the fluid path
between the exhaust end 105 of the compressor 101 and the four-way
valve 120 via the mid-pressure tank pressure-increasing control
valve 135, and the mid-pressure tank second outlet 182 is connected
to the suction end 106 of the compressor 101 via the mid-pressure
tank pressure-reducing control valve 136. The mid-pressure tank
first inlet 112 and the mid-pressure tank first outlet 128 are
mainly used for delivery of the refrigerant gas such that they are
provided at the top of the mid-pressure tank 110.
[0055] The mid-pressure tank 110 receives the high-pressure
refrigerant discharged from the heat exchangers which are capable
of acting as condensers via the mid-pressure tank first inlet 112
so that the refrigerant and pressure in the heat exchangers are
reduced but the refrigerant and pressure in the mid-pressure tank
110 are increased. The mid-pressure tank 110 can also supplement a
refrigerant to the refrigerant circulation loop of the heat pump
unit through the mid-pressure tank first outlet 128. If the
pressure is too high in the mid-pressure tank 110, the pressure can
be reduced by delivery of the refrigerant gas in the mid-pressure
tank 110 to the suction end 106 of the compressor 101 by opening
the mid-pressure tank pressure-reducing control valve 136. If the
pressure in the mid-pressure tank 110 is too low, the pressure can
be increased by delivery of the high-pressure refrigerant gas from
the exhaust end 105 of the compressor 101 to the mid-pressure tank
110 by opening the mid-pressure tank pressure-increasing control
valve 135. Thus, the pressure in the mid-pressure tank 110 can be
maintained within a desired range.
[0056] To further guarantee the flow direction of the fluid in the
mid-pressure tank 110, as an example, a first one-way valve 125.1
can be provided between the first valve 113.1 of the mid-pressure
tank first inlet control valve group and the mid-pressure tank
first inlet 112, and a second one-way valve 125.2 can be provided
between the second valve 113.2 of the mid-pressure tank first inlet
control valve group and the mid-pressure tank first inlet 112. The
first one-way valve 125.1 will be automatically opened when the
first valve 113.1 of the mid-pressure tank first inlet control
valve group is opened, and the second one-way valve 125.2 will be
automatically opened when the second valve 113.2 of the
mid-pressure tank first inlet control valve group is opened. A
one-way valve (not shown) can also be provided in the downstream
fluid path of the mid-pressure tank first outlet control valve
114.
[0057] Still as shown in FIG. 1, a pressure sensor 161 is provided
in the mid-pressure tank 110 for detecting the pressure in the
mid-pressure tank 110. Pressure sensors 164, 162, and 163 are
provided in the first heat exchanger 104, the second heat exchanger
102 and the third heat exchanger 103, respectively, for detecting
the pressure therein.
[0058] The heat pump unit further comprises a control device 230
(as shown in FIG. 2), and all the pressure sensors and control
valves in FIG. 1 are connected to the control device 230. FIGS. 2A,
2B, and 2C are block diagrams for the control device 230 of the
heat pump unit as shown in FIG. 1. As shown in FIG. 2A, the control
device 230 comprises a bus 242, a processor 244, an input interface
248, an output interface 252 and a memory 254 in which programs 256
and data 257 are stored. The processor 244, the input interface
248, the output interface 252 and the memory 254 are
communicatively connected to the bus 242 so that the processor 244
can control the operation of the input interface 248, the outlet
interface 252 and the memory 254. Specifically, the memory 254 is
configured for storing the programs 256, instructions and data 257,
the processor 244 can read the programs 256, instructions and data
257 from the memory 254 and can write data into the memory 254.
[0059] As shown in FIG. 2B, the output interface 252 is connected
through the connections 238 (238.1, 238.2, 238.3 . . . 238.9) to
all the control valves in FIG. 1, including the first valve 113.1
and second valve 113.2 of the mid-pressure tank first inlet control
valve group, the mid-pressure tank first outlet control valve 114,
the mid-pressure tank pressure-increasing control valve 135, the
mid-pressure tank pressure-reducing control valve 136, the first
valve 118.1, the second valve 118.2 and the third valve 118.3 of
the throttling-device-outlet-side control valve group, and the
four-way valve 120.
[0060] As shown in FIG. 2C, the input interface 248 is connected
through the connections 246.2, 246.3, 246.4, and 246.5 to the
pressure sensors 161, 162, 163, and 164, respectively, and receive
through the connection 246.1 operation requests to the heat pump
unit and other operation parameters. The processor 244 can control
the operation of the heat pump unit of the present disclosure by
performing reading the programs and the instructions via the memory
254.
[0061] More specifically, the control device 230 can receive the
operation requests from the heat pump unit (for example, the
requests sending from a control panel), the operation parameters
sending from the pressure sensors as shown in FIG. 1 and other
operation parameters of the heat pump unit via the input interface
248, and send control signals via the output interface 252 to the
control valves in FIG. 1. By controlling the control valves in FIG.
1, the heat pump unit is capable of running in multiple modes and
being switched between the multiple modes.
[0062] FIGS. 3A-3D illustrate the refrigerant circulation loops of
the heat pump unit of FIG. 1 running in four modes, respectively,
wherein the arrows indicate the flow directions and flow paths of
the refrigerant. FIG. 3A illustrates the refrigerant circulation
loop in a cooling only mode (Mode 1), FIG. 3B illustrates the
refrigerant circulation loop in a heating only mode (Mode 2), FIG.
3C illustrates the refrigerant circulation loop in a cooling plus
heating mode (Mode 3), while FIG. 3D illustrates the refrigerant
circulation loop in a defrosting mode (Mode 4).
[0063] Table 1 lists the status of the first valve 118.1, the
second valve 118.2, and the third valve 118.3 of the
throttling-device-outlet-side control valve group, and the four-way
valve 120 for the multiple modes of the heat pump unit. Table 1 can
be stored in the storage 254 as shown in FIG. 2A.
TABLE-US-00001 TABLE 1 Status of Valves for Various Heat Pump Unit
Modes Four-way valve Throttling-device-outlet-side control valve
Mode 120 118.1 118.2 118.3 Cooling only Powered off Closed Closed
Open mode Heating only Powered on Closed Open Closed mode Cooling
plus Powered on Closed Closed Open heating mode Defrosting Powered
off Open Closed Closed mode
[0064] In Table 1, when the four-way valve 120 is powered on, the
third interface 120.3 and the second interface 120.2 of the
four-way valve 120 are connected, while the first interface 120.1
and the fourth interface 120.4 are connected. When the four-way
valve 120 is powered off, the third interface 120.3 and the fourth
interface 120.4 of the four-way valve 120 are connected, while the
first interface 120.1 and the second interface 120.2 are
connected.
[0065] The heat pump unit of the present disclosure is capable of
running in the following modes by connecting two of the three heat
exchangers with the compressor 101 and the throttling device 107 to
form the refrigerant circulation loop, while leaving the third of
the heat exchangers connected in parallel with the one, which is on
the low-pressure side, of the two heat exchangers in the
refrigerant circulation loop for spare use and for start in other
modes.
[0066] Mode 1: Cooling Only
[0067] As shown in FIG. 3A and Table 1, if it is desired to run the
heat pump unit in the cooling only mode, controlling, via the
control device 230, the four-way valve 120 to power off it such
that the third interface 120.3 and the fourth interface 120.4 of
the four-way valve 120 are connected while the first interface
120.1 and the second interface 120.2 are connected, and
controlling, via the control device 230, the third valve 118.3 of
the throttling-device-outlet-side control valve group to open it.
The second valve 115.2 of the throttling-device-inlet-side control
valve group can be automatically opened since it is a one-way
valve. The other valves are closed. In this way, the high-pressure
refrigerant discharged from the exhaust end 105 of the compressor
101 first passes through the second heat exchanger 102, then flows
through the second valve 115.2 of the throttling-device-inlet-side
control valve group into the inlet end 108 of the throttling device
107 and is changed into a low-pressure refrigerant, then the
low-pressure refrigerant flows through the third valve 118.3 of the
throttling-device-outlet-side control valve group into the third
heat exchanger 103, and finally the refrigerant flows from the
third heat exchanger 103 to the suction end 106 of the compressor
101 to complete the circulation of the refrigerant.
[0068] In the cooling only mode, the compressor 101, the throttling
device 107, the second heat exchanger 102 and the third heat
exchanger 103 are in the refrigerant circulation loop, the second
heat exchanger 102 acts as a condenser, and the third heat
exchanger 103 acts as an evaporator and cools externally via the
second water supply and return pipe 111.2. The first heat exchanger
104 is for spare use and is connected in parallel with the third
heat exchanger 103, and the first heat exchanger 104 is not in the
refrigerant circulation loop.
[0069] Mode 2: Heating Only
[0070] As shown in FIG. 3B and Table 1, if it is desired to run the
heat pump unit in the heating only mode, controlling, via the
control device 230, the four-way valve 120 to power on it such that
the third interface 120.3 and the second interface 120.2 of the
four-way valve 120 are connected while the first interface 120.1
and the fourth interface 120.4 are connected, and controlling, via
the control device 230, the second valve 118.2 of the
throttling-device-outlet-side control valve group to open it. The
first valve 115.1 of the throttling-device-inlet-side control valve
group can be automatically opened since it is a one-way valve. The
other valves are closed. In this way, the high-pressure refrigerant
discharged from the exhaust end 105 of the compressor 101 first
passes through the first heat exchanger 104, then flows through the
first valve 115.1 of the throttling-device-inlet-side control valve
group into the inlet end 108 of the throttling device 107 and is
changed into a low-pressure refrigerant, then the low-pressure
refrigerant flows through the second valve 118.2 of the
throttling-device-outlet-side control valve group into the second
heat exchanger 102, and finally the refrigerant flows from the
second heat exchanger 102 to the suction end 106 of the compressor
101 to complete the circulation of the refrigerant.
[0071] In the heating only mode, the compressor 101, the throttling
device 107, the first heat exchanger 104 and the second heat
exchanger 102 are in the refrigerant circulation loop, the first
heat exchanger 104 acts as a condenser and heats externally via the
first water supply and return pipe 111.1, and the second heat
exchanger 102 acts as an evaporator. The third heat exchanger 103
is for spare use and is connected in parallel with the second heat
exchanger 102, and the third heat exchanger 103 is not in the
refrigerant circulation loop.
[0072] Mode 3: Cooling Plus Heating
[0073] As shown in FIG. 3C and Table 1, if it is desired to run the
heat pump unit in the cooling plus heating mode, controlling, via
the control device 230, the four-way valve 120 to power on it such
that the third interface 120.3 and the second interface 120.2 of
the four-way valve 120 are connected while the first interface
120.1 and the fourth interface 120.4 are connected, and
controlling, via the control device 230, the third valve 118.3 of
the throttling-device-outlet-side control valve group to open it.
The first valve 115.1 of the throttling-device-inlet-side control
valve group can be automatically opened since it is a one-way
valve. The other valves are closed. In this way, the high-pressure
refrigerant discharged from the exhaust end 105 of the compressor
101 first passes through the first heat exchanger 104, then flows
through the first valve 115.1 of the throttling-device-inlet-side
control valve group into the inlet end 108 of the throttling device
107 and is changed into a low-pressure refrigerant, then the
low-pressure refrigerant flows through the third valve 118.3 of the
throttling-device-outlet-side control valve group into the third
heat exchanger 103, and finally the refrigerant flows from the
third heat exchanger 103 to the suction end 106 of the compressor
101 to complete the circulation of the refrigerant.
[0074] In the cooling plus heating mode, the compressor 101, the
throttling device 107, the first heat exchanger 104 and the third
heat exchanger 103 are in the refrigerant circulation loop, the
first heat exchanger 104 acts as a condenser and heats externally
via the first water supply and return pipe 111.1, and the third
heat exchanger 103 acts as an evaporator and cools externally via
the second water supply and return pipe 111.2. The second heat
exchanger 102 is for spare use and is connected in parallel with
the third heat exchanger 103, and the second heat exchanger 102 is
not in the refrigerant circulation loop.
[0075] Mode 4: Defrosting
[0076] When the heat pump unit runs in the heating only mode and
the ambient temperature is low, the surface of the second heat
exchanger 102 as an air heat exchanger will be frosted and it is
desired to defrost the surface by heating it.
[0077] As shown in FIG. 3D and Table 1, if it is desired to run the
heat pump unit in the defrosting mode, controlling, via the control
device 230, the four-way valve 120 to power off it such that the
third interface 120.3 and the fourth interface 120.4 of the
four-way valve 120 are connected while the first interface 120.1
and the second interface 120.2 are connected, and controlling, via
the control device 230, the first valve 118.1 of the
throttling-device-outlet-side control valve group to open it. The
second valve 115.2 of the throttling-device-inlet-side control
valve group can be automatically opened since it is a one-way
valve. The other valves are closed. In this way, the high-pressure
refrigerant discharged from the exhaust end 105 of the compressor
101 first passes through the second heat exchanger 102, then flows
through the second valve 115.2 of the throttling-device-inlet-side
control valve group into the inlet end 108 of the throttling device
107 and is changed into a low-pressure refrigerant, then the
low-pressure refrigerant flows through the first valve 118.1 of the
throttling-device-outlet-side control valve group into the first
heat exchanger 104, and finally the refrigerant flows from the
first heat exchanger 104 to the suction end 106 of the compressor
101 to complete the circulation of the refrigerant.
[0078] In the defrosting mode, the compressor 101, the throttling
device 107, the first heat exchanger 104 and the second heat
exchanger 102 are in the refrigerant circulation loop, the second
heat exchanger 102 acts as a condenser and heats externally so that
the second heat exchanger 102 is defrosted, and the first heat
exchanger 104 acts as an evaporator. The third heat exchanger 103
is for spare use and is connected in parallel with the first heat
exchanger 104, and the third heat exchanger 103 is not in the
refrigerant circulation loop.
[0079] During the running of the heat pump unit in any of
above-mentioned modes, if the degree of super-cooling of the
refrigerant in the condenser is too high, the corresponding valve
113.1 or 113.2 in the mid-pressure tank first inlet control valve
group of the heat exchanger acting as the condenser is opened and
the redundant refrigerant in the heat exchanger acting as the
condenser is discharged into the mid-pressure tank 110; if the
degree of super-cooling is not too high, the corresponding valve
113.1 or 113.2 in the mid-pressure tank first inlet control valve
group is closed and the discharge of redundant refrigerant stops.
If the pressure in the low-pressure side of the running heat pump
unit is too low, the mid-pressure tank first outlet control valve
114 is opened and the refrigerant in the mid-pressure tank 110
flows to the low-pressure side of the running system via the
mid-pressure tank first outlet control valve 114 to supplement
refrigerant; if the pressure is no longer too low, the mid-pressure
tank first outlet control valve 114 is closed and refrigerant
supplementation stops. The closing and opening of the valve 113.1
or 113.2 and the valve 114 are controlled by the control device
230.
[0080] If the run mode of the heat pump unit is switched among the
aforementioned multiple modes, a pressure release operation may be
desired in some situations to the first heat exchanger 104 or the
second heat exchanger 102 which is capable of acting as a
condenser. Specifically, when a heat exchanger acting as a
condenser in a pre-switching run mode does not act as a condenser
in a post-switching run mode, then it is desired to perform the
pressure release operation.
[0081] Table 2 is the mode switching table for the heat pump unit
of FIG. 1. Whether a pressure release operation is desired during
the mode switching is summarized in Table 2. The activated valves
in each mode are also summarized in Table 2. The contents in Table
2 are stored in the storage 254 as shown in FIG. 2A. The processer
244 can determine whether it is desired to perform a pressure
release operation to the first heat exchanger 104 or the second
heat exchanger 102 by reading Table 2 after receiving a request of
switching the current run mode (i.e., a pre-switching run mode) of
the heat pump unit to a post-switching run mode.
TABLE-US-00002 TABLE 2 Status of Valves During Switching of Heat
Pump Unit Modes Activated valves Activated valves Activated valves
Pre-switching in the pre- Post-switching in the post- in the
pressure run mode switching run mode run mode switching run mode
release operation Cooling 118.3 Heating only 120/118.2 113.2 only
Cooling plus 120/118.3 113.2 heating Heating 120/118.2 Cooling only
118.3 113.1 only Cooling plus 120/118.3 No pressure heating release
operation Defrosting 118.1 113.1 Cooling 120/118.3 Cooling only
118.3 113.1 plus heating Heating only 120/118.2 No pressure release
operation Defrosting 118.1 Heating only 120/118.2 113.2
[0082] In Table 2, the four-way valve 120 is powered on when it is
activated and the control valves 118.1, 118.2, 118.3, 113.1 and
113.2 are opened when they are activated. The specific pressure
release operations to the heat exchangers may be described as
Operation 1, Operation 2, Operation 3, and Operation 4. Each of
Operations 1-4 is described in further detail below.
[0083] Operation 1 may include fluidly connecting the first heat
exchanger 104 to the mid-pressure tank first inlet 112 so as to
discharge the refrigerant from the first heat exchanger 104 to the
mid-pressure tank 110. Operation 1 corresponds to opening the valve
113.1 (i.e., the first valve 113.1 of the mid-pressure first inlet
control valve group) in Table 2.
[0084] Operation 2 may include fluidly connecting the second heat
exchanger 102 to the mid-pressure tank first inlet 112 so as to
discharge the refrigerant from the second heat exchanger 102 to the
mid-pressure tank 110. Operation 2 corresponds to opening the valve
113.2 (i.e., the second valve 113.2 of the mid-pressure first inlet
control valve group) in Table 2.
[0085] As indicated in Table 2, when it is desired to switch the
run mode of the heat pump unit from the cooling only mode (the
pre-switching run mode) to the heating only mode or the cooling
plus heating mode (the post-switching run mode), it is desired to
perform the pressure release operation to the second heat exchanger
102 since the second heat exchanger 102 acting as a condenser in
the cooling only mode does not act as a condenser in the heating
only mode or the cooling plus heating mode. The desired pressure
release operation to the second heat exchanger 102 is Operation
2.
[0086] When it is desired to switch the run mode of the heat pump
unit from the heating only mode (the pre-switching run mode) to the
cooling only mode or the defrosting mode (the post-switching run
mode), it is desired to perform the pressure release operation to
the first heat exchanger 104 since the first heat exchanger 104
acting as a condenser in the heating only mode does not act as a
condenser in the cooling only mode or the defrosting mode. The
desired pressure release operation to the first heat exchanger 104
is Operation 1.
[0087] When it is desired to switch the run mode of the heat pump
unit from the cooling plus heating mode (the pre-switching run
mode) to the cooling only mode (the post-switching run mode), it is
desired to perform the pressure release operation to the first heat
exchanger 104 since the first heat exchanger 104 acting as a
condenser in the cooling plus heating mode does not act as a
condenser in the cooling only mode. The desired pressure release
operation to the first heat exchanger 104 is Operation 1.
[0088] When it is desired to switch the run mode of the heat pump
unit from the defrosting mode (the pre-switching run mode) to the
heating only mode (the post-switching run mode), it is desired to
perform the pressure release operation to the second heat exchanger
102 since the second heat exchanger 102 acting as a condenser in
the defrosting mode does not act as a condenser in the heating only
mode. The desired pressure release operation to the second heat
exchanger 102 is Operation 2.
[0089] Still as indicated in Table 2, when it is desired to switch
the run mode of the heat pump unit between the heating only mode
and the cooling plus heating mode, no pressure release operation is
desired since the first heat exchanger 104 acts as a condenser in
both of the two modes.
[0090] Referring now to FIG. 4, a process flow diagram illustrating
a method 400 of switching the run mode for the heat pump unit of
FIG. 1 is depicted. The steps of the method 400 as shown are stored
in the storage 254 of the control device 230 and performed by the
control device 230.
[0091] Process 400 may commence with step 450. Step 450 may include
receiving a mode switching request, namely a request for switching
the run mode of the heat pump unit from the pre-switching run mode
to the post-switching run mode. The control device 230 receives the
mode switching request via the input interface 248. The mode
switching request is, for example, inputted by an operator via a
user interface connecting to the input interface 248, or
automatically sent from the heat pump unit according to the
operation parameters.
[0092] Process 400 may continue with step 451. Step may include
determining whether it is desired to perform the pressure release
operation to the first heat exchanger 104 or the second heat
exchanger 102. The control device 230 determines, according to
Table 2 stored in the storage 254, whether it is desired to perform
the pressure release operation to the first heat exchanger 104 or
the second heat exchanger 102 if the run mode of the heat pump unit
is to be switched from the pre-switching run mode to the requested
post-switching run mode. The control device 230 turns to Step 4521
if it is determined that it is desired to perform the pressure
release operation to the first heat exchanger 104, turns to Step
4522 if it is determined that it is desired to perform the pressure
release operation to the second heat exchanger 102, and turns to
Step 460 if it is determined that no pressure release operation is
desired to the first heat exchanger 104 or the second heat
exchanger 102.
[0093] Step 4521 may include performing the aforementioned
Operation 1 and then turning to Step 4531. By performing Operation
1, the first valve 113.1 of the mid-pressure first inlet control
valve group is opened such that the first heat exchanger 104 is
fluidly connected to the mid-pressure first inlet 112 to discharge
the refrigerant in the first heat exchanger 104 into the
mid-pressure tank 110.
[0094] Step 4522 may include performing the aforementioned
Operation 2 and then turning to Step 4532. By performing Operation
2, the second valve 113.2 of the mid-pressure first inlet control
valve group is opened such that the second heat exchanger 102 is
fluidly connected to the mid-pressure first inlet 112 to discharge
the refrigerant in the second heat exchanger 102 into the
mid-pressure tank 110.
[0095] Step 4531 may include determining whether a first
predetermined amount of time has elapsed since Operation 1 is
performed. If yes, it is considered that the pressure release
operation may be ended and the control device 230 turns to Step
4581. If not, the control device 230 continues to perform Step 4531
until it is determined that the first predetermined amount of time
has elapsed. The first predetermined amount of time can be
determined according to the cooling capacity/heating capacity of
the heat pump unit. As an example, the first predetermined amount
of time is about 30-60 seconds.
[0096] Step 4532 may include determining whether a second
predetermined amount of time has elapsed since Operation 2 is
performed. If yes, it is considered that the pressure release
operation may be ended and the control device 230 turns to Step
4582. If not, the control device 230 continues to perform Step 4532
until it is determined that the second predetermined amount of time
has elapsed. The second predetermined amount of time can be also
determined according to the cooling capacity/heating capacity of
the heat pump unit. As an example, the second predetermined amount
of time is about 30-60 seconds. The second predetermined amount of
time can be the same as or different from the first predetermined
amount of time.
[0097] Step 4581 may include performing Operation 3, namely,
disconnecting the first heat exchanger 104 from the mid-pressure
first inlet 112, and then turning to Step 460. Operation 3
corresponds to closing the valve 113.1 (i.e., the first valve 113.1
of the mid-pressure first inlet control valve group).
[0098] Step 4582 may include performing Operation 4, namely,
disconnecting the second heat exchanger 102 from the mid-pressure
first inlet 112, and then turning to Step 460. Operation 4
corresponds to closing the valve 113.2 (i.e., the second valve
113.2 of the mid-pressure first inlet control valve group).
[0099] Process 400 may conclude with step 460. Step 460 may include
starting the post-switching run mode and ending the pre-switching
run mode to finish the mode switching. In Step 460, the
post-switching run mode is started by activating the corresponding
valves which may be activated in the post-switching run mode. The
valves to be activated for each kind of post-switching run mode are
summarized in Table 2. Specifically, the valve 120 (i.e., the
four-way valve 120) and the valve 118.2 (i.e., the second valve
118.2 of the throttling-device-outlet-side control valve group)
will be activated if the post-switching run mode is the heating
only mode, the valve 118.3 (i.e., the third valve 118.3 of the
throttling-device-outlet-side control valve group) will be
activated if the post-switching run mode is the cooling only mode,
the valve 120 (i.e., the four-way valve 120) and the valve 118.3
(i.e., the third valve 118.3 of the throttling-device-outlet-side
control valve group) will be activated if the post-switching run
mode is the cooling plus heating mode, and the valve 118.1 (i.e.,
the first valve 118.1 of the throttling-device-outlet-side control
valve group) will be activated if the post-switching run mode is
the defrosting mode.
[0100] In Step 460, the pre-switching run mode is ended by
deactivating the corresponding valves which are activated in the
pre-switching run mode. The valves activated for each kind of
pre-switching run mode are summarized in Table 2. Specifically, the
valve 120 and the valve 118.2 will be deactivated if the
pre-switching run mode is the heating only mode, and the valve
118.3 will be deactivated if the pre-switching run mode is the
cooling only mode, the valve 120 and the valve 118.3 will be
deactivated if the pre-switching run mode is the cooling plus
heating mode, and the valve 118.1 will be activated if the
pre-switching run mode is the defrosting mode.
[0101] It should be noted that even though starting the
post-switching run mode and ending the pre-switching run mode are
performed in the same Step 460, the pre-switching run mode can be
ended after a certain time delay from starting the post-switching
run mode in other embodiments according to the present
disclosure.
[0102] According to the present disclosure, the control device 230
is further configured to perform Operation 5, namely, fluidly
connecting the mid-pressure tank first outlet 128 and the outlet
end 109 of the throttling device 107, if it is desired to
supplement refrigerant to the refrigerant circulation loop of the
post-switching run mode after the post-switching run mode is
started. Operation 5 corresponds to opening the mid-pressure tank
first outlet control valve 114. The control device 230 is further
configured to fluidly connecting the mid-pressure second inlet 181
to the exhaust end 105 of the compressor 101 by opening the
mid-pressure tank pressure-increasing control valve 135 if the
pressure sensor 161 detects that the pressure in the mid-pressure
tank 110 is below a first predetermined pressure value during
performing Operation 5. In this way, the pressure in the
mid-pressure tank 110 can be increased to ensure that the
refrigerant in the mid-pressure tank 110 can be supplemented into
the refrigerant circulation loop. As an example, the control device
230 is configured to close the mid-pressure tank
pressure-increasing control valve 135 if the pressure in the
mid-pressure tank 110 is increased above the pressure at the
mid-pressure first outlet 128.
[0103] According to the present disclosure, the control device 230
is further configured to fluidly connecting the mid-pressure tank
second outlet 182 to the suction end 106 of the compressor 101 by
opening the mid-pressure tank pressure-reducing control valve 136
if the pressure sensor 161 detects that the pressure in the
mid-pressure tank 110 is above a second predetermined pressure
value during performing Operation 1 or Operation 2. In this way,
the pressure in the mid-pressure tank 110 can be reduced to ensure
that the high-pressure refrigerant in the first heat exchanger 104
or the second heat exchanger 102 can be discharged into the
mid-pressure tank 110. As an example, the control device 230 is
configured to close the mid-pressure tank pressure-reducing control
valve 136 if the pressure in the mid-pressure tank 110 is reduced
below the pressure at the mid-pressure first inlet 112.
[0104] The aforementioned first predetermined pressure value and
second predetermined pressure value can be determined according to
the desired range of value for the pressure in the mid-pressure
tank 110.
[0105] Furthermore, according to the present disclosure, to further
ensure the effectiveness of the mode switching, the control device
230 is further configured to determine whether the pressure in the
heat exchanger to which the pressure release operation has been
performed is still high by detecting the pressure of the
refrigerant in the heat exchanger with the corresponding pressure
sensor 164/162. If yes, it is considered that the mode switching
fails and then the control device 230 stops the heat pump unit.
[0106] FIG. 5A illustrates the flow path of the refrigerant when
switching the run mode of the heat pump unit of FIG. 1 from the
cooling only mode to the cooling plus heating mode. The following
describes how to release pressure from the heat exchanger that
needs pressure release by taking some of the operations for
switching the run mode of the heat pump unit from the cooling only
mode to the cooling plus heating mode as an example.
[0107] If the run mode of the heat pump unit is to be switched from
the cooling only mode as shown in FIG. 3A to the cooling plus
heating mode as shown in FIG. 3C, the second heat exchanger 102
will be switched from the heat exchanger acting as a condenser on
the high-pressure side to a spare heat exchanger, and therefore
pressure release is desired to the second heat exchanger 102.
[0108] As shown in FIG. 5A, when the heat pump unit is still
running in the cooling only mode, the second valve 113.2 of the
mid-pressure tank first inlet control valve group is first opened
to fluidly connect the second heat exchanger 102 to the
mid-pressure tank first inlet 112 so that the high-pressure
refrigerant in the second heat exchanger 102 can be discharged into
the mid-pressure tank 110.
[0109] The pressure release operation to the second heat exchanger
102 as shown in FIG. 5A will be ended after the second
predetermined amount of time has elapsed. To end the pressure
release operation, the second valve 113.2 of the mid-pressure tank
first inlet control valve group will be closed to disconnect the
second port 121.2 of the second heat exchanger 102 from the
mid-pressure tank first inlet 112. After that, the run mode will be
switched from the cooling only mode to the cooling plus heating
mode by controlling the four-way valve 120 to power on it, so as to
connect the third interface 120.3 and the second interface 120.2 of
the four-way valve 120 and connect the fourth interface 120.4 and
the first interface 120.1. Since the third valve 118.3 of the
throttling-device-outlet-side control valve group is opened in both
of the cooling only mode and the cooling plus heating mode, the
switching to the cooling plus heating mode can be completed without
any operation to the third valve 118.3.
[0110] FIG. 5B illustrates the flow path of the refrigerant when
performing refrigerant supplement operation to the refrigerant
circulation loop of the heat pump unit of FIG. 1 running in the
cooling plus heating mode.
[0111] The refrigerant circulation loop of the heat pump unit may
need the refrigerant supplement operation when it is normally
running in the four modes. For example, after the run mode of the
heat pump unit is switched from the cooling only mode as shown in
FIG. 5A to the cooling plus heating mode as shown in FIG. 5B, the
refrigerant circulation loop in the cooling plus heating mode may
need refrigerant supplement due to the pressure release operation
as shown in FIG. 5A. To this end, as shown in FIG. 5B, the
mid-pressure first outlet control valve 114 is opened to fluidly
connect the mid-pressure first outlet 128 to the outlet end 109 of
the throttling device 107 so that the refrigerant in the
mid-pressure tank 110 can be supplemented into the refrigerant
circulation loop. In the meantime, if the pressure in the
mid-pressure tank 110 is not enough, the mid-pressure tank
pressure-increasing control valve 135 is opened to fluidly connect
the mid-pressure second inlet 181 to the exhaust end 105 of the
compressor 101 so as to increase the pressure in the mid-pressure
tank 110 to ensure that the refrigerant in the mid-pressure tank
110 can be supplemented into the refrigerant circulation loop.
[0112] By performing the pressure release operation to the heat
exchanger which needs the operation during mode switching, on the
one hand, the pressure shock caused when the heat exchanger on the
high-pressure side is switched to be a heat exchanger on the
low-pressure side at the time of mode switching can be prevented,
and on the other hand, the residual liquid refrigerant in the heat
exchanger on the high-pressure side is not enough to be brought
from the suction end into the compressor to cause a liquid shock
after mode switching. Furthermore, by performing the mode switching
method of the present disclosure, on the one hand, since the
pressure difference during pressure release is very small, the
vibration intensity during pressure release is also very small, and
on the other hand, the switching time is very short and the
corresponding shock force is also small. Therefore, this switching
process can be considered smoother and more efficient than a
conventional shutdown switching process.
[0113] As an example, if it is desired to switch the run modes, the
load of the compressor 101 can first be reduced so that the
refrigerant participating in the refrigerant circulation of the
heat pump unit is reduced, and the refrigerant can be discharged
into the mid-pressure tank 110 as much as possible. In addition, by
reducing the suction volume and discharge volume of the compressor,
the corresponding shock force at the time of mode switching will
also be very small.
[0114] In addition, through the receiving and supplementing of the
refrigerant by the mid-pressure tank 110, the shock caused by a
pressure jump at the time of mode switching on the heat pump unit
can be reduced, the service lives of the components can be
prolonged, and the running reliability and stability of the heat
pump unit can be improved. In addition, through the reasonable
control of the refrigerant in the refrigerant circulation loop of
the heat pump unit running in a normal run mode by the mid-pressure
tank 110, the reliability and the energy efficiency ratio of the
heat pump unit can be improved.
[0115] FIG. 6 is a block diagram of the heat pump unit according to
another embodiment of the present application. To further improve
the energy efficiency ratio and the running stability of the heat
pump unit, the embodiment of the heat pump unit as shown in FIG. 6
is provided. The embodiment as shown in FIG. 6 includes all the
components in FIG. 1 and is further provided with an oil separator
630, a drying filter 632 and an economizer 634 based on the heat
pump unit of FIG. 1.
[0116] As shown in FIG. 6, the oil separator 630 is located between
the exhaust end 105 of the compressor 101 and the four-way valve
120 and is configured to separate the oil discharged from the
compressor 101. The drying filter 632 is located at the upstream
side of the inlet end 108 of the throttling device 107 and the
drying filter 632 is configured to dry and filter the high-pressure
refrigerant before the high-pressure refrigerant flows into the
throttling device 107. The economizer 634 is located at the
downstream side of the drying filter 632. The outlet of the drying
filter 632 is connected to the liquid inlet on the super-cooling
side of the economizer 634, the liquid outlet on the super-cooling
side of the economizer 634 is connected to the inlet end 108 of the
throttling device 107, and the gas outlet of the economizer 634 is
connected to the gas replenishing port of the compressor 101. Thus,
the degree of super-cooling of the system, the gas delivery
capacity, and the performance of the heat pump unit can further be
improved.
[0117] Although the present disclosure is described by reference to
the specific implementation modes shown in the drawings, it should
be understood that the heat pump unit in the present disclosure can
have many variants, without departing from the spirit, scope and
background of the present application. Those skilled in the art
should also realize that different changes to the structural
details in the embodiments disclosed in the present application
should all fall within the spirit and scope of the present
application and the claims.
* * * * *