U.S. patent application number 16/472448 was filed with the patent office on 2020-06-18 for outdoor unit of heat-pump hot water dispenser.
The applicant listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Satoru KIKUGAWA.
Application Number | 20200191435 16/472448 |
Document ID | / |
Family ID | 63712919 |
Filed Date | 2020-06-18 |
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United States Patent
Application |
20200191435 |
Kind Code |
A1 |
KIKUGAWA; Satoru |
June 18, 2020 |
OUTDOOR UNIT OF HEAT-PUMP HOT WATER DISPENSER
Abstract
An outdoor unit includes an air heat exchanger; a compressor; a
water heat exchanger; an expansion valve; a fan that moves air
outside the outdoor unit into the air heat exchanger; a motor that
rotates the fan; a power device used for driving the compressor; a
heat sink located in a space that is an extension portion beyond
the air heat exchanger, of a channel of air moved by rotation of
the fan during heating of the water from outside the outdoor unit
into the air heat exchanger, where the heat sink dissipates heat
generated by the power device during driving of the compressor; and
a control unit that provides control, upon completion of a water
heating operation, to drive the compressor, to open the expansion
valve, and to rotate the fan in the same direction as the rotation
direction of the fan during heating of the water.
Inventors: |
KIKUGAWA; Satoru; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Tokyo |
|
JP |
|
|
Family ID: |
63712919 |
Appl. No.: |
16/472448 |
Filed: |
April 4, 2017 |
PCT Filed: |
April 4, 2017 |
PCT NO: |
PCT/JP2017/014048 |
371 Date: |
June 21, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24F 11/74 20180101;
F24H 9/2007 20130101; F24F 1/38 20130101; F24D 2200/12 20130101;
F24D 19/1054 20130101; F24H 4/04 20130101; F24F 1/24 20130101; F24D
17/02 20130101 |
International
Class: |
F24H 4/04 20060101
F24H004/04; F24H 9/20 20060101 F24H009/20 |
Claims
1. (canceled)
2. An outdoor unit of a heat-pump hot water dispenser, the outdoor
unit comprising: an air heat exchanger to exchange heat between air
outside the outdoor unit and a refrigerant; a compressor to
compress the refrigerant flowed out of the air heat exchanger; a
water heat exchanger to exchange heat between the refrigerant
flowed out of the compressor and water; an expansion valve to
reduce a pressure of the refrigerant flowed out of the water heat
exchanger; a fan to move air outside the outdoor unit into the air
heat exchanger; a motor to rotate the fan; a power device used for
driving the compressor, the expansion valve, and the motor; a heat
sink located in a space that is an extension portion beyond the air
heat exchanger, of a channel of air moved by rotation of the fan
during heating of the water from outside the outdoor unit into the
air heat exchanger, the heat sink dissipating heat generated by the
power device during driving of the compressor; and a controller to
provide control, upon completion of operation of heating of the
water, to rotate the fan in a direction opposite to a rotation
direction of the fan during heating of the water.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a U.S. national stage application of
International Patent Application No. PCT/JP2017/014048 filed on
Apr. 4, 2017, the disclosure of which is incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates to an outdoor unit of a
heat-pump hot water dispenser for heating water.
BACKGROUND
[0003] A heat-pump hot water dispenser for heating water is
conventionally used. For example, a heat-pump hot water dispenser
is used for boiling water. A heat-pump hot water dispenser includes
an outdoor unit that heats water and a hot water dispenser tank
unit that stores water. The outdoor unit includes an air heat
exchanger, a fan that moves air outside the outdoor unit into the
air heat exchanger, a motor that rotates the fan, a compressor that
compresses a refrigerant, a water heat exchanger, a power device
used for control of the compressor and of the motor, and a heat
sink that dissipates heat generated in the power device during
driving of the compressor.
[0004] Conventionally, when a boiling operation finishes, the air
heat exchanger is cooled, and the air heat exchanger cooled has an
effect of cooling the heat sink. Cooling of the heat sink may cause
dew condensation to form on a surface of the power device.
Formation of dew condensation on the surface may cause current
leakage from the power device, thereby preventing a normal
operation of the power device. A technology has been proposed in
which when dew condensation may occur, the number of revolutions
per unit time of the compressor is increased, or the switching loss
of the switching element included in the power device is increased,
to increase the temperature of the power device, thereby to reduce
or prevent formation of dew condensation on the surface of the
power device (see, e.g., Patent Literature 1).
PATENT LITERATURE
Patent Literature 1: Japanese Patent Application Laid-open No.
2010-25373
[0005] However, in the foregoing conventional technology, the heat
sink is cooled after termination of the operation of the power
device after completion of a water heating operation. This may
cause dew condensation to form on a surface of the power
device.
SUMMARY
[0006] The present invention has been made in view of the
foregoing, and it is an object of the present invention to provide
an outdoor unit of a heat-pump hot water dispenser (hereinafter
referred to as "heat-pump hot water dispenser's outdoor unit") that
reduces the formation of dew condensation on the power device after
completion of a water heating operation.
[0007] To solve the problem and achieve the object described above,
a heat-pump hot water dispenser's outdoor unit according to the
present invention includes: an air heat exchanger that exchanges
heat between air outside the outdoor unit and a refrigerant; a
compressor that compresses the refrigerant flowed out of the air
heat exchanger; a water heat exchanger that exchanges heat between
the refrigerant flowed out of the compressor and water; an
expansion valve that reduces a pressure of the refrigerant flowed
out of the water heat exchanger; a fan that moves air outside the
outdoor unit into the air heat exchanger; a motor that rotates the
fan; a power device used for driving the compressor, the expansion
valve, and the motor; a heat sink that is located in a space that
is an extension portion beyond the air heat exchanger, of a channel
of air moved by rotation of the fan during heating of the water
from outside the outdoor unit into the air heat exchanger, the heat
sink dissipating heat generated by the power device during driving
of the compressor; and a control unit that provides control, upon
completion of operation of heating of the water, to rotate the fan
in a direction opposite as a rotation direction of the fan during
heating of the water.
[0008] A heat-pump hot water dispenser's outdoor unit according to
the present invention provides an advantage in being capable of
reducing the formation of dew condensation on the power device
after completion of a water heating operation.
BRIEF DESCRIPTION OF DRAWINGS
[0009] FIG. 1 is a first diagram illustrating a configuration of a
heat-pump hot water dispenser according to a first embodiment.
[0010] FIG. 2 is a diagram schematically illustrating a cross
section of the heat-pump hot water dispenser's outdoor unit
according to the first embodiment when the outdoor unit is viewed
from one lateral side of the heat-pump hot water dispenser's
outdoor unit according to the first embodiment.
[0011] FIG. 3 is a diagram schematically illustrating a cross
section of the heat-pump hot water dispenser's outdoor unit
according to the first embodiment when the outdoor unit is viewed
from the front side of the heat-pump hot water dispenser's outdoor
unit according to the first embodiment.
[0012] FIG. 4 is a perspective view schematically illustrating the
inside of the heat-pump hot water dispenser's outdoor unit
according to the first embodiment.
[0013] FIG. 5 is a perspective view for describing a method of
attaching the heat sink to the power device that is attached to the
control board provided inside the heat-pump hot water dispenser's
outdoor unit according to the first embodiment.
[0014] FIG. 6 is a second diagram illustrating the configuration of
the heat-pump hot water dispenser according to the first
embodiment.
[0015] FIG. 7 is a flowchart illustrating an operation procedure of
the heat-pump hot water dispenser's outdoor unit according to the
first embodiment.
[0016] FIG. 8 is a flowchart illustrating an operation procedure of
a heat-pump hot water dispenser's outdoor unit according to a
second embodiment.
[0017] FIG. 9 is a diagram schematically illustrating a cross
section of the heat-pump hot water dispenser's outdoor unit
according to the second embodiment when the outdoor unit is viewed
from one lateral side of the heat-pump hot water dispenser's
outdoor unit according to the second embodiment.
[0018] FIG. 10 is a diagram illustrating a processing circuit in a
case in which at least a portion of components including a
communication unit, a control unit, a temperature acquisition unit,
a motor drive circuit, a compressor drive circuit, an expansion
valve drive circuit, and a timer included in the heat-pump hot
water dispenser's outdoor unit according to the first and second
embodiments is or are implemented by the processing circuit.
[0019] FIG. 11 is a diagram illustrating a processor in a case in
which at least a portion of the functions of the communication
unit, the control unit, the temperature acquisition unit, the motor
drive circuit, the compressor drive circuit, the expansion valve
drive circuit, and the timer included in the heat-pump hot water
dispenser's outdoor unit according to the first and second
embodiments is implemented by the processor.
DETAILED DESCRIPTION
[0020] A heat-pump hot water dispenser's outdoor unit according to
embodiments of the present invention will be described in detail
below with reference to the drawings.
[0021] Note that these embodiments are not intended to limit the
scope of this invention.
First Embodiment
[0022] A configuration of a heat-pump hot water dispenser 1
according to a first embodiment will first be described. FIG. 1 is
a first diagram illustrating a configuration of the heat-pump hot
water dispenser 1 according to the first embodiment. The heat-pump
hot water dispenser 1 includes a heat-pump hot water dispenser's
outdoor unit 2, which heats water; and a hot water dispenser tank
unit 3, which stores water. The term "heat-pump hot water
dispenser's outdoor unit 2" may hereinafter also be referred to
simply as "outdoor unit 2".
[0023] The outdoor unit 2 includes a water heat exchanger 4, which
exchanges heat between a refrigerant and water. The water heat
exchanger 4 is connected with an inlet pipe 5. The inlet pipe 5 is
also connected to the hot water dispenser tank unit 3. Water stored
in the hot water dispenser tank unit 3 flows through the inlet pipe
5 into the water heat exchanger 4. The water heat exchanger 4
heats, by the heated refrigerant, the water flowing from the hot
water dispenser tank unit 3 through the inlet pipe 5 into the water
heat exchanger 4, thus to generate hot water. The water heat
exchanger 4 is also connected with an outlet pipe 6. The outlet
pipe 6 is also connected to the hot water dispenser tank unit 3.
The hot water generated in the water heat exchanger 4 passes
through the outlet pipe 6 into the hot water dispenser tank unit 3,
and is then stored in the hot water dispenser tank unit 3.
[0024] The outdoor unit 2 further includes an air heat exchanger 7,
which exchanges heat between air outside the outdoor unit 2 and the
refrigerant; a fan 8, which moves the air outside the outdoor unit
2 into the air heat exchanger 7; and a motor 9, which rotates the
fan 8. One example of the fan 8 is a propeller fan. The outdoor
unit 2 further includes a compressor 10, capable of compressing the
refrigerant flowed out of the air heat exchanger 7; an expansion
valve 11, capable of expanding the compressed refrigerant; and a
refrigerant circuit 12, which is a refrigerant channel. The water
heat exchanger 4 exchanges heat between the refrigerant flowed out
of the compressor 10, and water. The expansion valve 11 is capable
of reducing the pressure of the refrigerant flowed out of the water
heat exchanger 4. One example of the expansion valve 11 is an
electronically controlled expansion valve.
[0025] The outdoor unit 2 further includes an exchanger temperature
detection sensor 13, which detects a temperature of the air heat
exchanger 7. The exchanger temperature detection sensor 13 is
attached to a pipe for the refrigerant flowing out of the air heat
exchanger 7, near the outlet of the pipe. This pipe is a part of
the refrigerant circuit 12. For example, the exchanger temperature
detection sensor 13 includes a thermistor, and detects a
temperature of the air heat exchanger 7 based on the resistance of
the thermistor.
[0026] In the air heat exchanger 7, heat is exchanged between the
refrigerant and air outside the outdoor unit 2. The refrigerant
flowed out of the air heat exchanger 7 is compressed by the
compressor 10, which increases the temperature of the refrigerant
in the compressor 10. The refrigerant compressed, and thus heated,
by the compressor 10 then flows into the water heat exchanger 4. In
the water heat exchanger 4, heat is exchanged between the
refrigerant compressed by the compressor 10 and the water flowed
out of the hot water dispenser tank unit 3 into the water heat
exchanger 4. This heats the water, and hot water is thus generated.
The refrigerant flows out of the water heat exchanger 4 into the
expansion valve 11, and is expanded in the expansion valve 11. The
refrigerant then flows into the air heat exchanger 7.
[0027] In the outdoor unit 2, the refrigerant repeatedly passes
from the air heat exchanger 7 through the compressor 10, the water
heat exchanger 4, and the expansion valve 11, in sequence, and then
back to the air heat exchanger 7. The outdoor unit 2 further
includes an outdoor air temperature detection sensor 14, which
detects an outdoor air temperature outside the outdoor unit 2. For
example, the outdoor air temperature detection sensor 14 includes a
thermistor, and detects an outdoor air temperature outside the
outdoor unit 2 based on the resistance of the thermistor.
[0028] FIG. 2 is a diagram schematically illustrating a cross
section of the heat-pump hot water dispenser's outdoor unit 2
according to the first embodiment when the outdoor unit 2 is viewed
from one lateral side of the heat-pump hot water dispenser's
outdoor unit 2 according to the first embodiment. As illustrated in
FIG. 2, the outdoor unit 2 further includes a heat sink 15, which
cools a power device used for driving the motor 9, the compressor
10, and the expansion valve 11. The power device is a semiconductor
device. The power device is not illustrated in FIG. 2.
[0029] The heat sink 15 is, for example, attached to the power
device, and is located in a space that is an extension portion
beyond the air heat exchanger 7, of the channel of the air moved by
rotation of the fan 8 during heating of the water from outside the
outdoor unit 2 into the air heat exchanger 7. That is, the heat
sink 15 is provided at a location where the heat sink 15 is exposed
to wind, generated by rotation of the fan 8, passed through the air
heat exchanger 7. The heat sink 15 dissipates heat generated by the
power device during driving of the compressor 10. The arrows of
FIG. 2 indicate that the wind generated by rotation of the fan 8
moves in the direction from the fan 8 to the air heat exchanger
7.
[0030] FIG. 3 is a diagram schematically illustrating a cross
section of the heat-pump hot water dispenser's outdoor unit 2
according to the first embodiment when the outdoor unit 2 is viewed
from the front side of the heat-pump hot water dispenser's outdoor
unit 2 according to the first embodiment. As illustrated in FIG. 3,
the outdoor unit 2 further includes the power device 16 used for
driving the motor 9, the compressor 10, and the expansion valve 11;
and a control board 17, which provides control to reduce the
formation of dew condensation on the power device 16 after
completion of a water heating operation. The control board 17 is
provided inside the outdoor unit 2, and the power device 16 is
attached to the control board 17.
[0031] FIG. 4 is a perspective view schematically illustrating the
inside of the heat-pump hot water dispenser's outdoor unit 2
according to the first embodiment. As illustrated in FIG. 4, the
heat sink 15 is, for example, attached to the power device 16, and
is located in a space 42 that is an extension portion beyond the
air heat exchanger 7, of a channel 41 of the air moved by rotation
of the fan 8 during heating of the water from outside the outdoor
unit 2 into the air heat exchanger 7. The arrows of FIG. 4 indicate
that the wind generated by rotation of the fan 8 moves in the
direction from the fan 8 to the air heat exchanger 7.
[0032] FIG. 5 is a perspective view for describing a method of
attaching the heat sink 15 to the power device 16 that is attached
to the control board 17 provided inside the heat-pump hot water
dispenser's outdoor unit 2 according to the first embodiment. In
the first embodiment, the power device 16 includes a first power
device unit 16a and a second power device unit 16b as illustrated
in FIG. 5. The first power device unit 16a has a first notch 16x
formed on one of a pair of lateral faces facing each other, and has
a second notch 16y formed on the other one of the pair of lateral
faces facing each other.
[0033] The second power device unit 16b has a hole 16z formed
therethrough in the thickness direction. The control board 17 has
three through-holes formed therein. One of the three through-holes
is a hole 17a. The first power device unit 16a is attached to the
control board 17 such that the first notch 16x of the first power
device unit 16a is aligned with the hole 17a, and the second notch
16y of the first power device unit 16a is aligned with one
through-hole, other than the hole 17a, formed in the control board
17. The second power device unit 16b is attached to the control
board 17 such that the hole 16z of the second power device unit 16b
is aligned with another through-hole, other than the hole 17a,
formed in the control board 17.
[0034] There are a first bolt 18a inserted through the hole 17a and
through the first notch 16x into a first hole of the heat sink 15;
a second bolt 18b inserted through the second notch 16y into a
second hole of the heat sink 15; and a third bolt 18c inserted
through the hole 16z into a third hole of the heat sink 15. The
first hole, the second hole, and the third hole are not
illustrated. The first bolt 18a, the second bolt 18b, and the third
bolt 18c respectively inserted into the corresponding holes of the
heat sink 15 each have a nut attached thereto, where no nut is
illustrated. The heat sink 15 is attached to the power device 16
using the first bolt 18a, the second bolt 18b, the third bolt 18c,
and the three nuts.
[0035] FIG. 6 is a second diagram illustrating the configuration of
the heat-pump hot water dispenser 1 according to the first
embodiment. As illustrated in FIG. 6, the hot water dispenser tank
unit 3 includes a communication unit 31, which communicates with
the outdoor unit 2. The control board 17 included in the outdoor
unit 2 includes a communication unit 21, which communicates with
the communication unit 31 of the hot water dispenser tank unit 3.
Upon completion of a water heating operation, the communication
unit 21 receives an operation completion signal, which is a signal
indicating completion of the water heating operation, from the
communication unit 31 of the hot water dispenser tank unit 3
[0036] The control board 17 further includes a memory 22, which
stores first information indicating a first reference temperature,
which is a lower limit temperature for determining whether to
perform a condensation prevention operation. The condensation
prevention operation is an operation to reduce the formation of dew
condensation on the power device 16 after completion of a water
heating operation. The control board 17 further includes a control
unit 23, which controls the condensation prevention operation; and
a temperature acquisition unit 24, which acquires, from the outdoor
air temperature detection sensor 14, information indicating the
outdoor air temperature outside the outdoor unit 2, and also
acquires, from the exchanger temperature detection sensor 13,
information indicating the temperature of the air heat exchanger
7.
[0037] When the communication unit 21 receives an operation
completion signal, which is a signal indicating completion of a
water heating operation, from the communication unit 31 of the hot
water dispenser tank unit 3, the control unit 23 controls the
condensation prevention operation in a case in which the outdoor
air temperature outside the outdoor unit 2 indicated by the
information acquired by the temperature acquisition unit 24 is
higher than the first reference temperature indicated by the first
information stored in the memory 22. Specifically, in a case in
which the outdoor air temperature outside the outdoor unit 2 is
higher than the first reference temperature upon completion of a
water heating operation, the control unit 23 provides control to
drive the compressor 10, to open the expansion valve 11, and to
rotate the fan 8 in the same direction as the rotation direction of
the fan 8 during heating of the water. For example, when the
expansion valve 11 is to be opened, the control unit 23 fully opens
the expansion valve 11. For example, in the condensation prevention
operation, the control unit 23 rotates the fan 8 at a rotation
speed lower than the rotation speed when a water heating operation
is being performed.
[0038] The control board 17 further includes a motor drive circuit
25, which drives the motor 9; a compressor drive circuit 26, which
drives the compressor 10; and an expansion valve drive circuit 27,
which drives the expansion valve 11. The motor drive circuit 25,
the compressor drive circuit 26 and the expansion valve drive
circuit 27 are controlled by the control unit 23 for operation.
[0039] In the condensation prevention operation, the operation of
the compressor 10 heats the refrigerant by the compressor 10, after
which no heat exchange takes place in the water heat exchanger 4
and the expansion valve 11 is open. This causes the refrigerant
flowed out of the compressor 10 to reach the air heat exchanger 7
in a heated state. That is, the temperature of the air heat
exchanger 7 becomes higher than a temperature when the compressor
10 is not in operation. In addition, rotation of the fan 8 causes
the wind that is the air flowing from outside the outdoor unit 2
into the inside of the outdoor unit 2 to be heated in the air heat
exchanger 7 while the wind passes through the air heat exchanger 7.
The wind heated in the air heat exchanger 7 then reaches the heat
sink 15, and heats the heat sink 15. This prevents the heat sink 15
from being cooled even after completion of the water heating
operation, thereby reducing the formation of dew condensation on
the power device 16.
[0040] The control board 17 further includes a timer 28, which
measures time. The memory 22 also stores second information
indicating a second reference temperature, which is a lower limit
temperature for determining whether to terminate the condensation
prevention operation after performing of the condensation
prevention operation. After starting of control regarding the
condensation prevention operation, the control unit 23 determines
whether the temperature of the air heat exchanger 7 indicated by
the information acquired by the temperature acquisition unit 24 is
higher than or equal to the second reference temperature indicated
by the second information stored in the memory 22. If it is
determined that the temperature of the air heat exchanger 7 is
higher than or equal to the second reference temperature, the
control unit 23 starts the timer 28 measuring time. When the time
period measured by the timer 28 reaches a predetermined time
duration to terminate the condensation prevention operation, the
control unit 23 provide control to stop operation of the motor 9
and of the compressor 10. Information on the predetermined time
duration is stored in the memory 22.
[0041] An operation of the heat-pump hot water dispenser's outdoor
unit 2 according to the first embodiment will next be described.
FIG. 7 is a flowchart illustrating an operation procedure of the
heat-pump hot water dispenser's outdoor unit 2 according to the
first embodiment. The description below describes an operation in
the condensation prevention operation.
[0042] The outdoor air temperature detection sensor 14 detects the
outdoor air temperature (S1). When the communication unit 21
receives the operation completion signal, which is a signal
indicating completion of a water heating operation, from the
communication unit 31 of the hot water dispenser tank unit 3, the
control unit 23 determines whether the outdoor air temperature
outside the outdoor unit 2 is higher than the first reference
temperature, which is used as the criterion of starting of the
condensation prevention operation (S2). If the control unit 23
determines that the outdoor air temperature outside the outdoor
unit 2 is lower than or equal to the first reference temperature,
which is used as the criterion of starting of the condensation
prevention operation (No at S2), the condensation prevention
operation is not performed.
[0043] If it is determined that the outdoor air temperature outside
the outdoor unit 2 is higher than the first reference temperature,
which is used as the criterion of starting of the condensation
prevention operation (Yes at S2), the control unit 23 provides
control to operate the compressor 10 and to open the expansion
valve 11 (S3). The operation at step S3 increases the temperature
of the air heat exchanger 7 to a temperature higher than the
temperature of the air heat exchanger 7 when the compressor 10 is
not in operation. The control unit 23 drives the motor 9 to rotate
the fan 8 (S4).
[0044] The exchanger temperature detection sensor 13 detects the
temperature of the air heat exchanger 7 (S5). The control unit 23
determines whether the temperature of the air heat exchanger 7 is
higher than or equal to the second reference temperature indicated
by the second information stored in the memory 22 (S6). If the
control unit 23 determines that the temperature of the air heat
exchanger 7 is lower than the second reference temperature (No at
S6), the operation of the outdoor unit 2 proceeds to step S5. If it
is determined that the temperature of the air heat exchanger 7 is
higher than or equal to the second reference temperature (Yes at
S6), the control unit 23 stops the operation of the fan 8 and of
the compressor 10 after a certain time period has elapsed since it
is determined that the temperature of the air heat exchanger 7 is
higher than or equal to the second reference temperature (S7). That
is, at step S7, the control unit 23 stops the operation of the fan
8 and of the compressor 10 after a predetermined time duration has
elapsed since it is determined that the temperature of the air heat
exchanger 7 is higher than or equal to the second reference
temperature.
[0045] As described above, upon completion of the water heating
operation, the control unit 23 of the outdoor unit 2 provides
control to drive the compressor 10, to open the expansion valve 11,
and to rotate the fan 8 in the same direction as the rotation
direction of the fan 8 during heating of the water. The control of
the control unit 23 heats the refrigerant by the compressor 10,
causes no heat exchange to occur in the water heat exchanger 4, and
opens the expansion valve 11 thereby causing the refrigerant flowed
out of the compressor 10 to reach the air heat exchanger 7 in a
heated state. That is, the temperature of the air heat exchanger 7
becomes higher than the temperature when the compressor 10 is not
in operation. In more detail, the temperature of the air heat
exchanger 7 becomes higher than a temperature around the air heat
exchanger 7.
[0046] In addition, rotation of the fan 8 causes the wind that is
the air flowing from outside the outdoor unit 2 into the inside of
the outdoor unit 2 to be heated in the air heat exchanger 7 while
the wind passes through the air heat exchanger 7. The wind heated
in the air heat exchanger 7 then reaches the heat sink 15. Due to
the wind heated reaching the heat sink 15, the heat sink 15 is not
cooled. No cooling of the heat sink 15 reduces the formation of dew
condensation on the power device 16 even after completion of the
water heating operation. That is, the heat-pump hot water
dispenser's outdoor unit 2 can reduce the formation of dew
condensation on the power device 16 after completion of the water
heating operation.
[0047] As described above, when the temperature of the air heat
exchanger 7 becomes higher than or equal to the second reference
temperature after starting of the condensation prevention
operation, the control unit 23 stops the condensation prevention
operation when a certain time period has elapsed that is sufficient
to determine that the heat sink 15 has been sufficiently heated.
That is, the heat-pump hot water dispenser's outdoor unit 2
performs the condensation prevention operation only under a
condition likely to induce dew condensation. This enables the
heat-pump hot water dispenser's outdoor unit 2 to prevent an
increase in power consumption.
[0048] Conventionally, completion of the water heating operation
when the outside air temperature is relatively high in summer
causes the heat sink 15 to be cooled, and this readily induce dew
condensation on the power device 16. In contrast, in winter when
the outdoor air temperature falls near 0.degree. C., even
completion of the water heating operation, which cools the heat
sink 15, is unlikely to cause dew condensation to form on the power
device 16. That is, the condensation prevention operation is
demanded in summer, rather than in winter. The heat-pump hot water
dispenser's outdoor unit 2 performs the condensation prevention
operation only under a condition likely to induce dew
condensation.
Second Embodiment
[0049] A heat-pump hot water dispenser's outdoor unit 2 according
to a second embodiment will next be described. The heat-pump hot
water dispenser's outdoor unit 2 according to the second embodiment
has the same configuration as the configuration of the heat-pump
hot water dispenser's outdoor unit 2 according to the first
embodiment. In the first embodiment, the control unit 23 provides
control, upon completion of the water heating operation, to drive
the compressor 10, to open the expansion valve 11, and to rotate
the fan 8 in the same direction as the rotation direction of the
fan 8 during heating of the water.
[0050] In the second embodiment, the control unit 23 provides
control, upon completion of the water heating operation, to rotate
the fan 8 in the direction opposite to the rotation direction of
the fan 8 during heating of the water. That is, upon completion of
the water heating operation, the control unit 23 causes the motor 9
to drive the fan 8 to rotate in the direction opposite to the
rotation direction of the fan 8 during heating of the water.
[0051] An operation of the heat-pump hot water dispenser's outdoor
unit 2 according to the second embodiment will next be described.
FIG. 8 is a flowchart illustrating an operation procedure of the
heat-pump hot water dispenser's outdoor unit 2 according to the
second embodiment. The description below describes an operation in
the condensation prevention operation.
[0052] The outdoor air temperature detection sensor 14 detects the
outdoor air temperature (S11). When the communication unit 21
receives the operation completion signal, which is a signal
indicating completion of the water heating operation, from the
communication unit 31 of the hot water dispenser tank unit 3, the
control unit 23 determines whether the outdoor air temperature
outside the outdoor unit 2 is higher than the first reference
temperature, which is used as the criterion of starting of the
condensation prevention operation (S12). If the control unit 23
determines that the outdoor air temperature outside the outdoor
unit 2 is lower than or equal to the first reference temperature,
which is used as the criterion of starting of the condensation
prevention operation (No at S12), the condensation prevention
operation is not performed.
[0053] If the control unit 23 determines that the outdoor air
temperature outside the outdoor unit 2 is higher than the first
reference temperature, which is used as the criterion of starting
of the condensation prevention operation (Yes at S12), the control
unit 23 provides control to rotate the fan 8 in the direction
opposite to the rotation direction of the fan 8 during heating of
the water (S13). The operation at step S13 causes the air outside
the outdoor unit 2 to reach the heat sink 15 without passing
through the air heat exchanger 7.
[0054] FIG. 9 is a diagram schematically illustrating a cross
section of the heat-pump hot water dispenser's outdoor unit 2
according to the second embodiment when the outdoor unit 2 is
viewed from one lateral side of the heat-pump hot water dispenser's
outdoor unit 2 according to the second embodiment. The
configuration illustrated in FIG. 9 is the same as the
configuration illustrated in FIG. 2. The arrows of FIG. 9 indicate
that the wind generated by rotation of the fan 8 moves in the
direction from the air heat exchanger 7 to the fan 8. As is
apparent from a comparison between FIG. 2 according to the first
embodiment and FIG. 9 according to the second embodiment, rotation
of the fan 8 in the second embodiment generates an wind in the
direction generally opposite to the direction of the wind generated
by rotation of the fan 8 in the first embodiment. That is, the
foregoing operation at step S13 causes the air outside the outdoor
unit 2 to reach the heat sink 15 without passing through the air
heat exchanger 7.
[0055] The exchanger temperature detection sensor 13 detects the
temperature of the air heat exchanger 7 (S14). The control unit 23
determines whether the difference between the temperature of the
air heat exchanger 7 and the outdoor air temperature upon
completion of the water heating operation is less than or equal to
a predetermined value (S15). Information indicating the
predetermined value is stored in the memory 22. If the control unit
23 determines that the difference is greater than the predetermined
value (No at S15), the operation of the outdoor unit 2 proceeds to
step S14. If it is determined that the difference is less than or
equal to the predetermined value (Yes at S15), the control unit 23
stops the operation of the fan 8 after a certain time period has
elapsed since it is determined that the difference is less than or
equal to the predetermined value (S16). That is, at step S16, the
control unit 23 stops the operation of the fan 8 after a
predetermined time duration has elapsed since it is determined that
the difference is less than or equal to the predetermined
value.
[0056] As described above, upon completion of the water heating
operation, the control unit 23 of the outdoor unit 2 provides
control to rotate the fan 8 in the direction opposite to the
rotation direction of the fan 8 during heating of the water.
Rotation of the fan 8 in the direction opposite to the rotation
direction during heating of the water enables the air outside the
outdoor unit 2 to reach the heat sink 15 without passing through
the air heat exchanger 7. As described above, the condensation
prevention operation is demanded in summer, rather than in winter.
Thus, rotation of the fan 8 in the direction opposite to the
rotation direction during heating of the water enables air at a
relatively high temperature to reach the heat sink 15 from outside
the outdoor unit 2 to reduce or prevent formation of dew
condensation on the power device 16.
[0057] As described above, similarly to the first embodiment, the
control unit 23 stops the condensation prevention operation when a
certain time period has elapsed that is sufficient to determine
that the heat sink 15 has been sufficiently heated after starting
of the condensation prevention operation. That is, the heat-pump
hot water dispenser's outdoor unit 2 performs the condensation
prevention operation only under a condition likely to induce dew
condensation, and thus can prevent an increase in power
consumption.
[0058] Upon completion of the water heating operation, the
heat-pump hot water dispenser's outdoor unit 2 may operate to
perform the condensation prevention operation of the first
embodiment in a case in which the outdoor air temperature outside
the outdoor unit 2 is higher than or equal to a predetermined
temperature, and to perform the condensation prevention operation
of the second embodiment in a case in which the outdoor air
temperature outside the outdoor unit 2 is lower than the
predetermined temperature.
[0059] FIG. 10 is a diagram illustrating a processing circuit 91 in
a case in which at least a portion of components including the
communication unit 21, the control unit 23, the temperature
acquisition unit 24, the motor drive circuit 25, the compressor
drive circuit 26, the expansion valve drive circuit 27, and the
timer 28 included in the heat-pump hot water dispenser's outdoor
unit 2 according to the first and second embodiments is or are
implemented by the processing circuit 91. That is, at least a
portion of the functions of the communication unit 21, the control
unit 23, the temperature acquisition unit 24, the motor drive
circuit 25, the compressor drive circuit 26, the expansion valve
drive circuit 27, and the timer 28 may be implemented by the
processing circuit 91.
[0060] The processing circuit 91 is dedicated hardware. That is,
the processing circuit 91 is, for example, a single circuit, a
composite circuit, a programmed processor, a parallel programmed
processor, an application specific integrated circuit (ASIC), a
field-programmable gate array (FPGA), or a combination thereof. One
or more of the communication unit 21, the control unit 23, the
temperature acquisition unit 24, the motor drive circuit 25, the
compressor drive circuit 26, the expansion valve drive circuit 27,
and the timer 28 may be implemented by dedicated hardware separate
from the remainder.
[0061] FIG. 11 is a diagram illustrating a processor 93 in a case
in which at least a portion of the functions of the communication
unit 21, the control unit 23, the temperature acquisition unit 24,
the motor drive circuit 25, the compressor drive circuit 26, the
expansion valve drive circuit 27, and the timer 28 of the heat-pump
hot water dispenser's outdoor unit 2 according to the first and
second embodiments is implemented by the processor 93. That is, at
least a portion of the functions of the communication unit 21, the
control unit 23, the temperature acquisition unit 24, the motor
drive circuit 25, the compressor drive circuit 26, the expansion
valve drive circuit 27, and the timer 28 may be implemented by the
processor 93, which executes a program stored in a memory 92. The
processor 93 is a central processing unit (CPU), a processing unit,
a computing unit, a microprocessor, a microcomputer, or a digital
signal processor (DSP). FIG. 11 also illustrates the memory 92.
[0062] In a case in which at least a portion of the functions of
the communication unit 21, the control unit 23, the temperature
acquisition unit 24, the motor drive circuit 25, the compressor
drive circuit 26, the expansion valve drive circuit 27, and the
timer 28 is implemented by the processor 93, the portion of the
functions is implemented by the processor 93, and software,
firmware, or a combination of software and firmware. The software
or firmware is described as a program, and is stored in the memory
92. The processor 93 reads and executes the program stored in the
memory 92 to implement the at least a portion of the functions of
the communication unit 21, the control unit 23, the temperature
acquisition unit 24, the motor drive circuit 25, the compressor
drive circuit 26, the expansion valve drive circuit 27, and the
timer 28.
[0063] That is, in a case in which at least a portion of the
functions of the communication unit 21, the control unit 23, the
temperature acquisition unit 24, the motor drive circuit 25, the
compressor drive circuit 26, the expansion valve drive circuit 27,
and the timer 28 is implemented by the processor 93, the heat-pump
hot water dispenser's outdoor unit 2 includes the memory 92 for
storing a program that causes the steps to be performed by at least
one or more of the communication unit 21, the control unit 23, the
temperature acquisition unit 24, the motor drive circuit 25, the
compressor drive circuit 26, the expansion valve drive circuit 27,
and the timer 28. It can also be said that the program stored in
the memory 92 causes a computer to perform a procedure or method
that is performed by at least one or more of the communication unit
21, the control unit 23, the temperature acquisition unit 24, the
motor drive circuit 25, the compressor drive circuit 26, the
expansion valve drive circuit 27, and the timer 28.
[0064] The memory 92 is, for example, a non-volatile or volatile
semiconductor memory such as a random access memory (RAM), a
read-only memory (ROM), a flash memory, an erasable programmable
read-only memory (EPROM), or an electrically erasable programmable
read-only memory (EEPROM); a magnetic disk, a flexible disk, an
optical disk, a compact disc, a MiniDisc, a digital versatile disk
(DVD), or the like.
[0065] Multiple functions of the communication unit 21, the control
unit 23, the temperature acquisition unit 24, the motor drive
circuit 25, the compressor drive circuit 26, the expansion valve
drive circuit 27, and the timer 28 may be provided such that a
portion of the multiple functions is or are implemented by
dedicated hardware, and the remainder of the multiple functions is
or are implemented by software or firmware. Thus, the multiple
functions of the communication unit 21, the control unit 23, the
temperature acquisition unit 24, the motor drive circuit 25, the
compressor drive circuit 26, the expansion valve drive circuit 27,
and the timer 28 can be implemented by hardware, software,
firmware, or a combination thereof.
[0066] The configurations described in the foregoing embodiments
are merely examples of various aspects of the present invention.
These configurations may be combined with a known other technology,
and moreover, a part of such configurations may be omitted or
modified without departing from the spirit of the present
invention.
* * * * *