EP2933580A1

EP2933580A1 - Hot water generator

Info

Publication number: EP2933580A1
Application number: EP15163142.1A
Authority: EP
Inventors: Kenichi Watanabe; Masakazu Nomura; Hiroshi Mihara
Original assignee: Panasonic Intellectual Property Management Co Ltd
Current assignee: Panasonic Intellectual Property Management Co Ltd
Priority date: 2014-04-11
Filing date: 2015-04-10
Publication date: 2015-10-21
Also published as: JP2015203509A; CN104976764A

Abstract

A hot water generator comprising: a heat pump device formed by annularly connecting, to one another through refrigerant pipes, a compressor 3, a water-refrigerant heat exchanger 4, a decompressor 5 and an evaporator 6a; a heat medium path 12 a through which heat medium heated by the water-refrigerant heat exchanger 4 flows; a hot water tank 15 in which heat med ium or hot water heated by the heat medium is stored; an over pressure relief valve 11 for releasing pressure in an interi or of the heat medium path 12a when this pressure becomes eq ual to or higher than predetermined pressure; an air vent va lve 17 for venting air in the interior of the heat medium pat h 12a; and a casing 29 in which at least the water-refrigera nt heat exchanger 4, the heat medium path 12a, the hot water tank 15, the overpressure relief valve 11 and the air vent v alve 17 are accommodated, wherein the casing 29 is provided with an operating portion cover 25 which can open and close, or can attach and detached, and the overpressure relief val ve 11 and the air vent valve 17 are placed on an inner side o f the operating portion cover 25. This hot water generator has excellent installation performance and maintenance perfo rmance, and an installation area thereof can be saved.

Description

[TECHNICAL FIELD]

The present invention relates to a hot water generator in which hot water produced using a heat pump technique is stored.

[BACKGROUND TECHNIQUE]

Conventionally, a heating device using combustion-based fuel such as petroleum and gas as a heat source is utilized in most of cases, but in recent years, heating market utilizing a heat pump technique expands exponentially.
In a hot water heating device utilizing the heat pump technique, heat exchange is carried out between high temperature refrigerant and water, and hot water heated by the heat exchange is supplied or utilized for heating a room in a heating terminal such as a floor heating panel.
As a configuration of a heat pump hot water heating device, a heat pump device is placed outside, and a heat exchange unit for exchanging heat between water and high temperature refrigerant produced by the heat pump device to produce hot water and a hot water tank for storing the produced hot water are separately placed indoors in many cases (see patent document 1 for example).

[PRIOR ART DOCUMENT]

[PATENT DOCUMENT]

[PATENT DOCUMENT1] PCT International Publication No.2005/106346

[SUMMARY OF THE INVENTION]

[PROBLEM TO BE SOLVED BY THE INVENTION]

According to the conventional configuration, however, since the heat exchange unit and the hot water tank unit are separately placed indoors, there is a problem that an installation area is increased.
The present invention has been accomplished to solve the conventional problem, and the invention can provide a hot water generator capable of saving an installation area and having excellent installation performance and maintenance performance.

[MEANS FOR SOLVING THE PROBLEM]

To solve the conventional problem, the present invention provides a hot water generator comprising: a heat pump device formed by annularly connecting, to one another through refrigerant pipes, a compressor, a water-refrigerant heat exchanger, a decompressor and an evaporator; a heat medium path through which heat medium heated by the water-refrigerant heat exchanger flows; a hot water tank in which heat medium or hot water heated by the heat medium is stored; an overpressure relief valve for releasing pressure in an interior of the heat medium path when this pressure becomes equal to or higher than predetermined pressure; an air vent valve for venting air in the interior of the heat medium path; and a casing in which at least the water-refrigerant heat exchanger, the heat medium path, the hot water tank, the overpressure relief valve and the air vent valve are accommodated, wherein the casing is provided with an operating portion cover which can open and close, or can attach and detached, and the overpressure relief valve and the air vent valve are placed on an inner side of the operating portion cover.
According to this, the installation area can be saved. Further, the overpressure relief valve and the air vent valve used at the time of installation or maintenance can easily be exposed by the operating portion cover which is provided in the casing such that the operating portion cover can open and close or can be attachable and detachable. Therefore, it is possible to enhance the installation performance and the maintenance performance of the hot water generator. When the operating portion cover is closed, the overpressure relief valve and the air vent valve are kept out of user's sight, it is possible to enhance appearance of the hot water generator.

[EFFECT OF THE INVENTION]

According to the present invention, it is possible to provide a hot water generator capable of saving an installation area and having excellent installation performance and maintenance performance.

[BRIEF DESCRIPTION OF THE DRAWINGS]

Fig. 1 is a diagram showing a configuration of a hot water generator according to an embodiment of the present invention;
Fig. 2 is a schematic diagram of a configuration showing a connection relation of the hot water generator;
Fig. 3 is a perspective view of a hot water tank unit of the hot water generator;
Fig. 4 is a front view showing an interior structure of the hot water tank unit of the hot water generator; and
Fig. 5 is a perspective view showing the interior structure of the hot water tank unit of the hot water generator.

[MODE FOR CARRYING OUT THE INVENTION]

A first aspect of the present invention provides a hot water generator comprising: a heat pump device formed by annularly connecting, to one another through refrigerant pipes, a compressor, a water-refrigerant heat exchanger, a decompressor and an evaporator; a heat medium path through which heat medium heated by the water-refrigerant heat exchanger flows; a hot water tank in which heat medium or hot water heated by the heat medium is stored; an overpressure relief valve for releasing pressure in an interior of the heat medium path when this pressure becomes equal to or higher than predetermined pressure; an air vent valve for venting air in the interior of the heat medium path; and a casing in which at least the water-refrigerant heat exchanger, the heat medium path, the hot water tank, the overpressure relief valve and the air vent valve are accommodated, wherein the casing is provided with an operating portion cover which can open and close, or can attach and detached, and the overpressure relief valve and the air vent valve are placed on an inner side of the operating portion cover.
According to this, since the hot water tank and the water-refrigerant heat exchanger are accommodated in one casing, the installation area of the hot water generator can be reduced. The overpressure relief valve and the air vent valve which are used at the time of installation or maintenance are placed on the inner side of the operating portion cover which can open and close or can be attachable and detachable with respect to the casing. Therefore, an easily exposable structure can be realized. Hence, it is possible to enhance the installation performance and the maintenance performance of the hot water generator. When the operating portion cover is closed, the overpressure relief valve and the air vent valve are kept out of user's sight, it is possible to enhance appearance of the hot water generator.
According to a second aspect of the invention, in the first aspect, the hot water generator further includes a pressure gauge for measuring the pressure in the interior of the heat medium path, and a remote control having a function to adjust temperature of the heat medium or the hot water, and the pressure gauge and the remote control are placed on the inner side of the operating portion cover.
According to this, since the remote control is placed on the inner side of the operating portion cover, it is possible to prevent the remote control from being damaged by an erroneous operation or an erroneous operation and an external factor, and it is possible to enhance usability and durability of the remote control.
When the operating portion cover is closed and the remote control and the pressure gauge are covered with the operating portion cover together with the air vent valve and the overpressure relief valve, since the remote control, the pressure gauge, the air vent valve and the overpressure relief valve are kept out of user's sight, it is possible to enhance appearance of the hot water generator itself.
The remote control may be placed at a position exposed to outside of the hot water tank unit. Since the remote control is used by a user, if the remote control is placed at the position exposed to outside of the hot water tank unit, usability of the user can be enhanced. Further, the pressure gauge which measures pressure in the heat medium path may always be placed at a position exposed to outside of the hot water tank unit. To recognize abnormality of the hot water generator, it is preferable that the pressure gauge is placed at a position which can easily be visually checked. Hence, if the pressure gauge is always placed at the position exposed to outside of the hot water tank unit, it is possible to swiftly deal with abnormality when abnormality occurs.
According to a third aspect of the invention, in the first or second aspect, the operating portion cover is provided at a location higher than a central location in a height direction of the casing.
According to this, the overpressure relief valve, the pressure gauge, the air vent valve and the remote control are collectively placed at a position where a user can easily operate the hot water generator and where an operator who installs the hot water generator can easily operate (e.g., eye-level position). Therefore, it is possible to provide the hot water generator having excellent usability and installation performance.
According to a fourth or fifth aspect of the invention, in the first or second aspect, the hot water generator further comprises: a heat pump unit including the compressor, the water-refrigerant heat exchanger, the decompressor and the evaporator; and a hot water tank unit including the water-refrigerant heat exchanger, the heat medium path and the hot water tank, the hot water tank unit is provided with a refrigerant connecting portion to which the refrigerant pipe to be connected to the heat pump unit is connected, and a heater connecting portion to which a heat medium pipe for supplying the heat medium to a heater terminal is connected, a front surface panel configuring the casing is provided below the operating portion cover, and the refrigerant connecting portion and the heater connecting portion are placed on the inner side of an front surface panel.
According to this, since the refrigerant connecting portion and the heater connecting portion are located below the operating portion cover, when the refrigerant connecting portion and the heater connecting portion are placed in a room such as a basement room having a limited height, they can be installed without regard to a surface (ceiling) configuring an upper limit of the room space.
The front surface panel can be fixed through a fastening member or the like after the pipes are connected to the refrigerant connecting portion and the heater connecting portion. Since the refrigerant connecting portion and the heater connecting portion are placed at locations opposed to an inner surface of the front surface panel, the refrigerant connecting portion and the heater connecting portion are kept out of user's sight after connection of the pipes, and it is possible to enhance appearance of the hot water generator.
When the water supply pipe through which water is supplied to the hot water tank and the hot water supply pipe through hot water is supplied from the hot water tank to the hot water supply terminal are connected to the hot water tank unit, the hot water supply connecting portion to which the hot water supply pipe is connected is also placed at a location opposed to the inner surface of the front surface panel in addition to the refrigerant connecting portion and the heater connecting portion.
An embodiment of the present invention will be described with reference to the drawings below. The invention is not limited to this embodiment.
Fig. 1 is a circuit diagram of a hot water generator according to the embodiment of the present invention. The hot water generator of the embodiment includes a heat pump unit 1 placed outside and a hot water tank unit 2 placed indoors. The hot water tank unit 2 is connected to a heater terminal 19 through a heat medium pipe 20. A water supply pipe 31 through which water is supplied from a water pipe or the like to the hot water tank unit 2, and an outgoing-hot water pipe 30 through which hot water is supplied to the hot water supply terminal 33 are connected to the hot water tank unit 2.
Fig. 2 is a diagram showing a connection configuration of the hot water generator in the embodiment. The heat pump unit 1 and the hot water tank unit 2 of the hot water generator are connected to each other through a refrigerant pipe 8. The heat pump unit 1 and the hot water tank unit 2 are connected to each other through an electric wiring 18. A control device 21 is placed in the hot water tank unit 2. The control device 21 transmits a control signal to the heat pump unit 1 through the electric wiring 18. The hot water tank unit 2 and the heater terminal 19 (e.g., floor heating) are connected to each other through a heat medium pipe 20. The outgoing-hot water pipe 30 is connected to the hot water tank unit 2. Hot water is supplied to the hot water supply terminal 33 through the outgoing-hot water pipe 30. The water supply pipe 31 is connected to the hot water tank unit 2. Water is supplied to a hot water tank 15 through the water supply pipe 31.
The heat pump unit 1 includes a compressor 3 for compressing refrigerant and discharging high temperature refrigerant, a decompressor 5 for decompressing refrigerant, an evaporator 6a for exchanging heat between air and refrigerant, and a four-way valve 7 for switching between flow paths of refrigerant. The compressor 3, the decompressor 5, the evaporator 6a and the four-way valve 7 are connected to each other through the refrigerant pipe 8. An electromagnetic expansion valve or a capillary tube is used as the decompressor 5. The heat pump unit 1 is provided with a blast fan 6b. The blast fan 6b sends air to the evaporator 6a, and facilitates the heat exchange between air and refrigerant. The heat pump unit 1 covers the compressor 3, the decompressor 5, the evaporator 6a, the blast fan 6b and the four-way valve 7 with a heat pump casing.
A water-refrigerant heat exchanger 4 exchanges heat between heat medium and high temperature refrigerant to produce high temperature heat medium. The water-refrigerant heat exchanger 4 is placed in the hot water tank unit 2. The water-refrigerant heat exchanger 4 configures a heat pump cycle (heat pump device) by annularly connecting the compressor 3, the decompressor 5, the evaporator 6a and the four-way valve 7 to each other through the refrigerant pipe 8. As the water-refrigerant heat exchanger 4, it is possible to use a plate-type heat exchanger for example. Alternatively, it is also possible to use a double pipe heat exchanger as the water-refrigerant heat exchanger 4. In the double pipe heat exchanger, a refrigerant pipe through which refrigerant flows is placed in the heat medium pipe 20 through which heat medium flows.
It is preferable that the heat pump unit 1 is placed outside and the hot water tank unit 2 is placed indoors.
The heat pump unit 1 and the hot water tank unit 2 may be provided in one casing. The heat pump device may be accommodated in the hot water tank unit (casing) 2. When the heat pump unit 1 and the hot water tank unit 2 are provided in one casing, the hot water generator may be placed indoors or outside.
As refrigerant which circulates through the heat pump device, it is possible to use CFC-based refrigerant such as R410A and R407, and natural refrigerant such as CO₂. Kinds of refrigerant are not especially limited.
The hot water tank 15 in which high temperature hot water is stored is placed in the hot water tank unit 2. The hot water tank 15 is covered with a heat insulator such as foam, and this enhance thermal of water stored in the hot water tank 15.
A heat medium circuit 12 through which heat medium flows is placed in the hot water tank unit 2. The heat medium circuit 12 includes a heat medium path 12a and a bypass path 12b.
The heat medium path 12a connects, to each other, a heater connecting portion 20a located upstream of heat medium and a heater connecting portion 20b located downstream of heat medium. Heat medium flows into the heater connecting portion 20a from outside of the hot water tank unit 2, and heat medium flows out into the heater connecting portion 20b from an interior of the hot water tank unit 2.
The heat medium path 12a is provided a circulation pump 9, the water-refrigerant heat exchanger 4, a heater portion 14 and a three-way valve 16 in this order from an upstream side (from the side of the heater connecting portion 20a) with respect to a flowing direction of the heat medium. The heat medium path 12a is provided with a flow switch 10, an overpressure relief valve 11, an expansion tank 13, an air vent valve 17 and a pressure gauge 23.
The bypass path 12b branches off from the three-way valve 16, passes through a heat exchanger 15a provided in the hot water tank 15, and is connected to the heat medium path 12a located upstream of the circulation pump 9. The heat medium path 12a is connected to the heater terminal 19 through the heater connecting portions (20a, 20b), and the heat medium path 12a and the bypass path 12b configure the heat medium circuit 12.
The flow switch 10 detects flow of water or hot water. The flow switch 10 is placed downstream of the circulation pump 9 and the water-refrigerant heat exchanger 4, i.e., at a position where heat medium after it exchanges heat with the water-refrigerant heat exchanger 4 flows. Since the flow switch 10 is placed downstream of the circulation pump 9, it is possible to detect an operation state of the circulation pump 9. Further, since the flow switch 10 is placed downstream of the water-refrigerant heat exchanger 4, it is possible to detect that heat medium freezes in the water-refrigerant heat exchanger 4 and that a flow rate of heat medium is reduced. In this embodiment, the flow switch 10 is provided in the heat medium pipe 20 between the water-refrigerant heat exchanger 4 and the heater portion 14. Thee flow switch 10 detects a flow rate of heat medium flowing through the heat medium circuit 12.
In this embodiment, a DC pump is used as the circulation pump 9. When the hot water generator is installed, it is necessary to set a flow rate of heat medium flowing through the heat medium circuit 12 within a predetermined range in accordance with a size and a heat radiation amount of the heater terminal 19 connected to the heat medium circuit 12. The flow rate of the heat medium is set by a remote control 22 when the hot water generator is installed. In this embodiment, a circulation amount of heat medium by the circulation pump 9 can be set by selecting one of seven stages by the remote control 22.
The heat medium circuit 12 is provided with the heater portion 14 having electric heating means (heater) placed in a case forming a flow path through which heat medium flows. Since heat medium flows through the heater portion 14, the heat medium is heated to predetermined temperature by the heater.
The heater portion 14 can be used when outside air temperature is low and heating ability of the heat pump device is deteriorated and heat medium can not sufficiently be heated by heat radiation of refrigerant in the water-refrigerant heat exchanger 4. The heater portion 14 can be used also when the heat pump device fails.
The heater portion 14 can be used also when the heat pump device carries out a defrosting operation for example and if temperature of heat medium flowing through the heat medium circuit 12 is lowered and heat medium in the heat medium circuit 12 freezes. According to this, it is possible to prevent a dead water region from generating, and to prevent heat medium in the water-refrigerant heat exchanger 4 where the heat medium easily freezes from freezing. Further, the heater portion 14 can be used also when water in the hot water tank 15 is heated to high temperature (e.g., 70°C or higher) that cannot be heated by the heat pump device. The heater portion 14 can be used when water in the hot water tank 15 is sterilized. When water in the hot water tank 15 is sterilized, it is preferable that heat medium is heated to 60°C or higher by the heater portion 14.
The hot water tank 15 may further be provided with another heater, and water in the hot water tank 15 may directly be heated.
The heat medium path 12a is provided with the expansion tank 13 and the overpressure relief valve 11 for adjusting pressure. If a volume of the heat medium in the heat medium circuit 12 expands by heating the heat medium by the water-refrigerant heat exchanger 4, heat medium of an amount corresponding to the expansion of the volume is absorbed by the expansion tank 13. When inner pressure in the heat medium circuit 12 rises to predetermined pressure or higher, heat medium in the heat medium circuit 12 can be discharged out from the heat medium circuit 12 by the overpressure relief valve 11. In this embodiment, the expansion tank 13 is provided at the heat medium pipe 20 at a location downstream of the three-way valve 16. The overpressure relief valve 11 is mounted on the heater portion 14.
The heat medium circuit 12 in the hot water tank unit 2 is provided with the air vent valve 17. The air vent valve 17 has a function to automatically discharge air staying in the valve to outside. Therefore, since the air vent valve 17 is placed in the middle of the heat medium circuit 12, air remaining in the heat medium circuit 12 can be discharged to outside of the heat medium circuit 12. It is preferable that the air vent valve 17 is provided at the highest position in the heat medium path 12a. Air in the heat medium circuit 12 stays at the highest position in the heat medium circuit 12 due to its buoyance. Therefore, if the air vent valve 17 is provided at the highest position in the heat medium circuit 12, it is possible to easily vent air in the heat medium circuit 12. Although the air vent valve 17 is mounted on the heater portion 14 in this embodiment, a position of the air vent valve 17 is not especially limited only if the air vent valve 17 is provided at the highest position in the heat medium circuit 12.
The heat medium path 12a is provided with the pressure gauge 23. According to this, it is possible to check the pressure in the heat medium circuit 12. Although the pressure gauge 23 is provided in the heat medium path 12a between the three-way valve 16 and the heater connecting portion 20b, a position of the pressure gauge 23 is not especially limited.
The bypass path 12b configuring a portion of the heat medium circuit 12 is provided in the hot water tank unit 2. The bypass path 12b branches off from the three-way valve 16, and is connected to the heat medium path 12a between the heater connecting portion 20a and the circulation pump 9 through the heat exchanger 15a provided in the hot water tank 15.
The three-way valve 16 is provided in the heat medium path 12a downstream of the heater portion 14. The three-way valve 16 can switch flowing directions of the heat medium heated by the water-refrigerant heat exchanger 4 toward the hot water tank 15 or toward downstream of the heat medium path 12a. According to this, if the heat medium is made to flow toward the hot water tank 15, water stored in the hot water tank 15 can be heated by the heat exchanger 15a. If the heat medium is made to flow toward the downstream of the heat medium path 12a, the heat medium flows through the heater terminal 19 (i.e., heater terminal 19) provided in the middle of the heat medium circuit 12 outside the hot water tank unit 2, and a heating operation can be carried out. Of heat medium flowing from the water-refrigerant heat exchanger 4, the three-way valve 16 may be able to adjust a flow rate of heat medium flowing toward the hot water tank 15 and a flow rate of heat medium flowing toward the downstream of the heat medium path 12a.
It is preferable that heat medium flowing through the bypass path 12b flows in from a relatively upper connection opening 15b with respect to a height direction of the hot water tank 15, and heat medium after it exchanges heat in the heat exchanger 15a flows out from a relatively lower connection opening 15c. According to this, it is possible to efficiently heat water in the hot water tank 15.
The water supply pipe 31 through which water from a water pipe flows is connected to the hot water tank 15. Water from a water pipe or the like flows into a lower portion of the hot water tank 15 through a decompression valve 32 and a hot water supply connecting portion 30a provided in the hot water tank unit 2. The outgoing-hot water pipe 30 from which water in the hot water tank 15 flows out is connected to the hot water tank 15 at a position higher than the water supply pipe 31. Water (or hot water) in the hot water tank 15 flows out from an upper portion of the hot water tank 15 into the outgoing-hot water pipe 30. Thereafter, water (or hot water) flows to outside of the hot water tank unit 2 from a hot water supply connecting portion 30b, and is supplied to the hot water supply terminal 33 such as a tap or a shower. It is preferable that a mixing water faucet 34 for mixing water from the water supply pipe 31 and hot water from the outgoing-hot water pipe 30 with each other is provided on an upstream side of the hot water supply terminal 33. The decompression valve 32 may be provided outside the hot water tank unit 2 or inside the hot water tank unit 2.
In this embodiment, heat medium is heated by the water-refrigerant heat exchanger 4 and the heated heat medium flows into the heat exchanger 15a, thereby heating water in the hot water tank 15. That is, water in the hot water tank 15 is indirectly heated through heat medium using heat of refrigerant which circulates through the heat pump device. However, heat medium heated by the water-refrigerant heat exchanger 4 may be stored in the hot water tank 15 as it is. That is, heat medium heated by the water-refrigerant heat exchanger 4 may directly be stored in the hot water tank 15. In this case, it is preferable that a pipe through which water is supplied from a water pipe is connected to the heat medium circuit 12.
When heat medium heated by the water-refrigerant heat exchanger 4 is directly stored in the hot water tank 15, one end of the heat exchanger 15a is connected to the water supply pipe 31 and the other end of the heat exchanger 15a is connected to the outgoing-hot water pipe 30. It is preferable that water flowing through the water supply pipe 31 is heated by heat medium stored in the hot water tank 15 while this water flows through the heat exchanger 15a, and the water flows out from the outgoing-hot water pipe 30, and is supplied to the hot water supply terminal 33. According to this, if high temperature heat medium is stored in the hot water tank 15, when hot water becomes necessary in the hot water supply terminal 33, water can be heated by the heat exchanger 15a and can be supplied to the hot water supply terminal 33.
The heater connecting portions (20a, 20b) provided in the hot water tank unit 2 are connected to the heater terminal 19 such as a radiator and a floor heating panel through the heat medium pipe 20. According to this, the heat medium path 12a configures the heat medium circuit 12. The heater connecting portions (20a, 20b) can be attached to and detached from the heat medium pipe 20.
Operations of the hot water generator in this embodiment of the present invention will be described below.
The hot water generator in this embodiment can execute at least a heating operation for supplying heat medium to the heater terminal 19 provided in the middle of the heat medium circuit 12 and heating a room, a hot water storing operation for storing high temperature heat medium or hot water in the hot water tank 15, and a defrosting operation for melting frost which adheres to the evaporator 6a. These operations are started when a user instructs to start the operations through the remote control 22, or when the control device 21 of the hot water generator determines that it is necessary to execute the operations depending upon time zone or temperature around the hot water generator.
When a user instructs to start the heating operation through the remote control 22, or when the control device 21 determines that the heating operation is necessary based on temperature in a room, the control device 21 starts the heating operation. In the heating operation, the control device 21 drives the compressor 3 of the heat pump device and the circulation pump 9 provided in the heat medium circuit 12. When the decompressor 5 is an electromagnetic expansion valve, the control device 21 adjusts its valve opening degree.
Further, the control device 21 switches the three-way valve 16 toward the downstream of the heat medium circuit 12. According to this, refrigerant circulates through the heat pump device. Heat medium circulates through the heat medium circuit 12 and flows through the heater terminal 19. A user can adjust, by means of the remote control 22, temperature of heat medium flowing through the heat medium circuit 12 and supplied to the heater terminal 19. Here, as the adjustment of temperature of heat medium carried out by the remote control 22, it is possible to specifically specify predetermined temperature or to designate a plurality of stages (e.g., "high", "middle" and "low").
If the compressor 3 is driven, refrigerant circulates through the heat pump device. The refrigerant is compressed by the compressor 3, and is brought into a high temperature and high pressure state. The high temperature and high pressure refrigerant flows into the water-refrigerant heat exchanger 4 through the four-way valve 7, and radiates heat to heat medium. The refrigerant which flows out from the water-refrigerant heat exchanger 4 is decompressed by the decompressor 5. The refrigerant which flows out from the decompressor 5 exchanges heat with air sent by the blast fan 6b in the evaporator 6a, and evaporates. Thereafter, the refrigerant which flows out from the evaporator 6a flows into the compressor 3 through the four-way valve 7, and is again compressed. The refrigerant circulates through the heat pump device in this manner.
By driving the circulation pump 9, heat medium circulates through the heat medium circuit 12. The heat medium which circulates through the heat medium circuit 12 is heated by heat of refrigerant in the water-refrigerant heat exchanger 4, and temperature of the heat medium becomes high. Here, the three-way valve 16 is set such that heat medium flows toward a downstream side of the heat medium circuit 12. Hence, heat medium which flows out from the water-refrigerant heat exchanger 4 and flows through the heater portion 14 flows out into the external heat medium circuit 12 of the hot water tank unit 2 through the three-way valve 16 and the heater connecting portion 20a, and flows into the heater terminal 19 (e.g., floor heating). After heat medium radiates heat in the heater terminal 19, the heat medium again flows into the heat medium path 12a from the heater connecting portion 20a. The heat medium circulates through the heat medium circuit 12 in this manner.
The control device 21 controls the heat pump device and the circulation pump 9 such that temperature of heat medium supplied to the heater terminal 19 becomes equal to predetermined temperature. For example, the number of rotations of the compressor 3 and the decompressor 5 are controlled such that temperature (outgoing-hot water temperature) of heat medium which flows out from the water-refrigerant heat exchanger 4 becomes equal to target temperature, and the number of rotations of the circulation pump 9 is controlled such that temperature (entering-water temperature) of heat medium which flows into the water-refrigerant heat exchanger 4 becomes equal to predetermined temperature. That is, the heat pump device controls discharge temperature for bringing temperature (discharge temperature) of refrigerant discharged from the compressor 3 into predetermined temperature, and the circulation pump 9 controls entering-water temperature for adjusting temperature (entering-water temperature) of heat medium which flows into the water-refrigerant heat exchanger 4. When heat medium can not sufficiently be heated only by the heat pump device, the control device 21 heats heat medium using the heater portion 14.
If a user instructs to start the hot water storing operation through the remote control 22, or when the control device 21 determines that the hot water storing operation is necessary based on temperature of water in the hot water tank 15 or time zone, the control device 21 start the hot water storing operation. In the hot water storing operation, the control device 21 drives the compressor 3 of the heat pump device and the circulation pump 9 provided in the heat medium circuit 12. When the decompressor 5 is the electromagnetic expansion valve, the control device 21 adjusts its valve opening degree.
In the hot water storing operation, the control device 21 switches the three-way valve 16 toward the bypass path 12b. According to this, refrigerant circulates through the heat pump device, and heat medium flows through the heat exchanger 15a. A user can adjust, by means of the remote control 22, temperature of heat medium supplied to the heat exchanger 15a. Here, as the adjustment of temperature of heat medium carried out by the remote control 22, it is possible to specifically specify predetermined temperature or to designate a plurality of stages (e.g., "high", "middle" and "low").
Heat medium flowing into the bypass path 12b and flowing through the heat exchanger 15a radiates heat to water stored in the hot water tank 15 and heats the water. According to this, high temperature water is stored in the hot water tank 15. In the hot water supply operation, heated water flows out into the outgoing-hot water pipe 30, flows out to outside of the hot water tank unit 2 through the hot water supply connecting portion 30b, and is supplied to the hot water supply terminal 33. That is, the hot water supply operation is carried out using high temperature water stored in the hot water tank 15.
In the hot water storing operation, the control device 21 controls the heat pump device and the circulation pump 9 such that temperature of heat medium supplied to the heat exchanger 15a becomes equal to predetermined temperature. For example, the number of rotations of the compressor 3 and the decompressor 5 are controlled such that temperature (outgoing-hot water temperature) of heat medium flowing out from the water-refrigerant heat exchanger 4 becomes equal to target temperature, and the number of rotations of the circulation pump 9 is controlled such that temperature (entering-water temperature) of heat medium flowing into the water-refrigerant heat exchanger 4 becomes equal to predetermined temperature. When heat medium can not sufficiently be heated only by the heat pump device, the control device 21 heats heat medium using the heater portion 14.
When outside air temperature becomes equal to or lower than predetermined temperature, or when temperature of refrigerant flowing through the evaporator 6a becomes equal to or lower than predetermined temperature, the control device 21 determines that frost adheres to the evaporator 6a, and the control device 21 executes a defrosting operation for removing the frost. In the defrosting operation, the control device 21 switches a circulation direction of refrigerant by the four-way valve 7. According to this, refrigerant flows through the compressor 3, the four-way valve 7, the evaporator 6a, the decompressor 5, the water-refrigerant heat exchanger 4, the four-way valve 7 and the compressor 3 in this order. As a result, high temperature and high pressure refrigerant flows into the evaporator 6a, and the defrosting operation is carried out.
In the defrosting operation, low temperature and low pressure refrigerant flows into the water-refrigerant heat exchanger 4. According to this, temperature of heat medium in the heat medium circuit 12 is lowered. Especially, since heat medium is less prone to flow in a dead water region in the water-refrigerant heat exchanger 4, heat medium freezes in some cases. Hence, when temperature of heat medium flowing into the water-refrigerant heat exchanger 4 is less than predetermined temperature for example, the control device 21 activates the heater portion 14, heats heat medium, and the heated heat medium is made to circulate through the heat medium circuit 12. According to this, it is possible to prevent heat medium in the heat medium circuit 12 from freezing. If the defrosting operation is carried out during execution of the heating operation or the hot water storing operation, it is possible to suppress the temperature reduction of heat medium supplied to the heater terminal 19 or the heat exchanger 15a, and usability is enhanced.
Next, a layout structure of the functional parts of especially the hot water tank unit 2 of the hot water generator will be described.
Fig. 3 is a perspective view showing outward appearance of the hot water tank unit 2, Fig. 4 is a front view showing an interior structure of the hot water tank unit 2 from which a front surface panel 29a is detached, and Fig. 5 is a perspective view showing an internal structure of the hot water tank unit 2 from which the front surface panel 29a, an upper surface panel 29b, side surface panels 29c, and fixing plate 21a to which the control device 21 is fixed are detached.
In the present invention, the hot water tank 15, the water-refrigerant heat exchanger 4 and the heat medium path 12a are accommodated in one panel structure body (casing) 29 to configure the hot water tank unit 2, thereby enhancing installation performance when the hot water generator is installed, maintenance performance and appearance of the hot water generator.
Here, the installation construction work of and a maintenance method of the hot water generator will first be described. At the time of the installation operation, an operator who installs the hot water generator first installs the hot water tank unit 2 indoors, and installs the heat pump unit 1 outside. Then, the heat pump unit 1 and the hot water tank unit 2 are connected to each other through the refrigerant pipe 8. The hot water tank unit 2 and the heater terminal 19 are connected to each other through the heat medium pipe 20 so that heat medium circulates through the heater terminal 19 (e.g., floor heating). Water is supplied to the hot water tank 15, and to discharge water (or hot water) from the hot water tank 15, the water supply pipe 31 and the outgoing-hot water pipe 30 are connected to the hot water tank unit 2.
Next, an operation to flow heat medium into the heat medium circuit 12 is carried out. To vent air existing in the heat medium circuit 12, the circulation pump 9 is activated to circulate heat medium through the heat medium circuit 12 in a state where a cap provided in the air vent valve 17 is loosened. According to this, air in the heat medium circuit 12 is removed. At the time of a test operation of the hot water generator, the circulation pump 9 is operated by the remote control 22.
When it is not possible to completely vent air even by means of the air vent valve 17, a lever of the overpressure relief valve 11 is turned in a state where heat medium circulates through the heat medium circuit 12 so that air remaining in the heat medium circuit 12 is removed through the overpressure relief valve 11. When predetermined time is elapsed after the lever of the overpressure relief valve 11 is turned, the lever of the overpressure relief valve 11 is returned to its original position. This operation is repeated until air is completely removed. At this time, it is checked whether the overpressure relief valve 11 is appropriately operated.
Next, it is checked, by means of the pressure gauge 23, whether pressure of water in the heat medium circuit 12 is appropriate. Next, to check whether the heating operation is appropriately carried out, a test heating operation of the hot water generator is carried out. At this time, the circulation pump 9 is first activated, and when predetermined time is elapsed, the heat pump device is activated. According to this, since the heat pump device is activated in a state where heat medium circulates through the heat medium circuit 12, this prevents excessive pressure from generating in the heat pump device.
When a test operation of the hot water generator is carried out, it is checked whether current temperature of the heat medium indicated on the remote control 22 rises, whether air in the heat medium circuit 12 is completely removed, whether the heater terminal 19 is sufficiently heated, whether heat medium does not leak from the overpressure relief valve 11, whether a value indicated by the pressure gauge 23 is appropriate (e.g., 0.1 to 0.19 MPa), and whether abnormal alarm is not displayed on the remote control 22.
In the installation construction work of the hot water generator, as described above, it is necessary that the refrigerant pipe 8, the heat medium pipe 20, the water supply pipe 31 and the outgoing-hot water pipe 30 are connected to each other, operations of the air vent valve 17, the overpressure relief valve 11 and the pressure gauge 23 are checked, and a test operation of the hot water generator is carried out. Therefore, it is preferable that these functional parts are placed so that the installation operator can easily carry out the installation construction work.
The air vent valve 17 and the overpressure relief valve 11 are relatively frequently used at the time of the maintenance after the installation construction work of the hot water generator is completed. Therefore, it is preferable that the air vent valve 17 and the overpressure relief valve 11 are placed at positions where these valves can easily be operated.
From such a viewpoint, according to the present invention, the casing 29 is provided with an operating portion cover 25 which can open and close with respect to the casing 29 or can be attached to and detached from the casing 29 as shown in Fig. 3, and the air vent valve 17 and the overpressure relief valve 11 are placed on an inner side of the operating portion cover 25. Further, refrigerant connecting portions 8a and 8b to which the refrigerant pipe 8 is connected, the heater connecting portions 20a, 20b to which the heat medium pipe 20 is connected, the hot water supply connecting portion 30a to which the water supply pipe 31 is connected, and the hot water supply connecting portion 30b to which the outgoing-hot water pipe 30 is connected are provided at an inner side of the front surface panel 29a which is placed below the operating portion cover 25. The refrigerant connecting portions 8a and 8b, the heater connecting portions 20a, 20b, the hot water supply connecting portion 30a and the hot water supply connecting portion 30b are pipe connecting portions 40.
A layout structure of the functional parts of the hot water tank unit 2 will be described in detail below. As shown in Fig. 3, the hot water tank unit 2 is covered with the casing 29 formed from a stainless steel plate. The casing 29 includes the front surface panel 29a covering a front surface of the hot water tank unit 2, the upper surface panel 29b covering an upper surface thereof, the side surface panels 29c covering side surfaces thereof, and a rear surface panel 29d covering a rear surface thereof. An operating portion panel 29e is provided above the front surface panel 29a. The operating portion panel 29e is offset, by a predetermined distance, from an outer surface of the front surface panel 29a toward an inner side of the hot water tank unit 2. The panels 29a to 29e configuring the casing 29 are fixed each other or to a frame body (not shown) through fastening members such as bolts. The side surface panels 29c are both a right side surface panel 29c and a left side surface panel 29c (not shown in Fig. 3) as viewed from the front surface panel 29a.
The operating portion cover 25 is mounted on the upper casing 29 of the front surface panel 29a or a frame body. The operating portion cover 25 is provided on the front surface panel 29a such that the operating portion cover 25 can open and close. A portion of the operating portion cover 25 is fixed to any of the front surface panel 29a, the upper surface panel 29b, the side surface panels 29c and the frame body of the casing 29. In this embodiment, the operating portion cover 25 is connected to the frame body to which the front surface panel 29a and the right side surface panel 29c are fixed through a turnably hinge (not shown). The operating portion cover 25 turns from a close position to an open position around an axis Z which is parallel to the frame body to which the operating portion cover 25 is fixed. A user or an installation operator can manually open, close, attach or detach the operating portion cover 25 without using a tool. A position where the operating portion cover 25 is fixed, a direction of the axis around which the operating portion cover 25 turns, and a position of the operating portion cover 25 are not especially limited. For example, the operating portion cover 25 may be fixed to an upper end of the front surface panel 29a, and the operating portion cover 25 may turn around a horizontal axis which is parallel to the upper end.
When the operating portion cover 25 is at the close position (close state), an outer surface of the operating portion cover 25 configures the same surface as an outer peripheral surface of the casing 29 (the front surface panel 29a). According to this, appearance of the hot water tank unit 2 is enhanced. When the operating portion cover 25 is at the close position, the operating portion cover 25 and the operating portion panel 29e are opposed to each other. On the other hand, when the operating portion cover 25 is at the open position (open state) as shown in Fig. 3, the operating portion panel 29e is exposed to outside.
At least the overpressure relief valve 11 and the air vent valve 17 are placed on the operating portion panel 29e. Therefore, when the operating portion cover 25 is at the close position, the overpressure relief valve 11 and the air vent valve 17 are covered with the operating portion cover 25 and are not exposed to outside, and when the operating portion cover 25 is in the open position, the overpressure relief valve 11 and the air vent valve 17 are exposed to outside.
In this embodiment, the remote control 22 and the pressure gauge 23 are also placed on the operating portion panel 29e. Therefore, when the operating portion cover 25 is at the close position, the overpressure relief valve 11, the air vent valve 17, the remote control 22 and the pressure gauge 23 are covered with the operating portion cover 25 and are not exposed to outside, and when the operating portion cover 25 is at the open position, the overpressure relief valve 11, the air vent valve 17, the remote control 22 and the pressure gauge 23 are exposed to outside.
By the operating portion cover 25 which is provided on the casing 29 of the hot water tank unit 2 and which can open and close, the overpressure relief valve 11 and the air vent valve 17 which are used at the time of the installation operator and the maintenance can easily be exposed and operated. Especially when inner pressure of the heat medium circuit 12 excessively rises, since the operating portion cover 25 can open and the overpressure relief valve 11 can be operated, it is possible to swiftly handle abnormality of the hot water generator. Hence, the installation performance and the maintenance performance are enhanced.
In this embodiment, the overpressure relief valve 11, the air vent valve 17, the remote control 22 and the pressure gauge 23 are collectively placed on the operating portion panel 29e. Therefore, when the operating portion cover 25 is closed, the functional parts are not exposed from the outer surface of the hot water tank unit 2. Hence, it is possible to enhance the appearance of the hot water tank unit 2.
When the operating portion cover 25 is closed, since the remote control 22 is covered with the operating portion cover 25, it is possible to prevent the remote control 22 from being erroneously operated and from being damaged. As a result, durability of the remote control 22 can be enhanced.
When the overpressure relief valve 11 and the remote control 22 are placed on the inner side of the operating portion cover 25, it is preferable that the remote control 22 is placed at a position other than below the overpressure relief valve 11. Heat medium flowing through the heat medium circuit 12 flows out from the overpressure relief valve 11 in some cases. Therefore, if the remote control 22 is placed at a position other than below the overpressure relief valve 11, it is possible to prevent heat medium flowing out from the overpressure relief valve 11 from adhering to the remote control 22. As a result, it is possible to avoid inconvenience of the remote control 22.
It is preferable that the operating portion cover 25 is located above a central portion of the hot water tank unit 2 in the height direction. In this embodiment, the operating portion cover 25 is placed on the side of a front surface of the hot water tank unit 2, and above the front surface panel 29a, and at the highest location of the hot water tank unit 2. According to this, a user and an installation operator can easily visually check the overpressure relief valve 11, the air vent valve 17, the remote control 22 and the pressure gauge 23, and these members are located at positions where they can easily be operated. Therefore, installation performance and maintenance performance are enhanced. It is unnecessary that the operating portion cover 25 is located at the height location in the height direction of the hot water tank unit 2. That is, a panel configuring a portion of the casing 29 may be provided above the operating portion cover 25.
In this embodiment, the operating portion cover 25 can turn around the predetermined axis Z provided on the right side as viewed from the front surface panel 29a, and the operating portion cover 25 can open and close in a front surface direction of the hot water tank unit 2, but the other configurations may also be employed. For example, the operating portion cover 25 may be formed into a slidable structure, and a portion of the front surface of the hot water tank unit 2 may open and close. The operating portion cover 25 may be provided with a hook, the hook is hitched to the casing 29 or the frame body, and the operating portion cover 25 may be attached to and detached from the casing 29. That is, it is only necessary that the operating portion cover 25 can open and close with respect to the casing 29 or can be attached to and detached from the casing 29, and the presence or absence of exposure of the operating portion panel 29e can be switched by the close state and the open state.
In this embodiment, the overpressure relief valve 11 and the air vent valve 17 are placed on the operating portion panel 29e, but the overpressure relief valve 11 and the air vent valve 17 may not be fixed to the operating portion panel 29e. That is, when the operating portion cover 25 is in the close state, the overpressure relief valve 11 and the air vent valve 17 are opposed to the inner surface of the operating portion cover 25, and when the operating portion cover 25 is in the open state, the overpressure relief valve 11 and the air vent valve 17 are exposed to outside. As shown in Fig. 4 for example, a portion of the operating portion panel 29e may be notched, and the overpressure relief valve 11 and the air vent valve 17 may be provided in the notch.
When the overpressure relief valve 11, the air vent valve 17, the remote control 22 and the pressure gauge 23 are covered with covers, a cover for covering the overpressure relief valve 11 and the air vent valve 17 and a cover for covering the remote control 22 and the pressure gauge 23 may separately be provided.
Although the operating portion panel 29e is provided above the front surface panel 29a in this embodiment, the operating portion panel 29e may be provided above the side surface panel 29c.
The remote control 22 and the pressure gauge 23 may be placed on the same surface as the casing 29. That is, the remote control 22 and the pressure gauge 23 may be placed at positions always exposed to outside of the hot water tank unit 2. The remote control 22 is always used for adjusting temperature of heat medium and temperature of water which is supplied to the hot water supply terminal 33. To recognize abnormality of the hot water generator, it is preferable that the pressure gauge 23 is placed at a position which can always visually be checked. Hence, if the remote control 22 and the pressure gauge 23 are placed at a position which is always exposed to outside, usability of a user can be enhanced, and when the hot water generator becomes abnormal, it is possible to swiftly handle the abnormality.
Next, an internal structure of the hot water tank unit 2 will be described. If the front surface panel 29a is detached, the control device 21 provided in the hot water tank unit 2, and the pipe connecting portions 40 are exposed to outside.
The control device 21 is fixed the fixing plate 21a. The fixing plate 21a is fixed to the side surface panels 29c or the frame body through the support tool 21b using a fastening member. The pipe connecting portions 40 are provided below the control device 21 and at positions having a predetermined height L from the installed surface of the hot water tank unit 2. According to the above-described configuration, the operating portion panel 29e, the control device 21 and the pipe connecting portions 40 are placed on the front surface side of the hot water tank unit 2 in this order from above. According to this, if the operating portion cover 25 is opened and the front surface panel 29a is detached, all of the overpressure relief valve 11, the air vent valve 17, the remote control 22, the pressure gauge 23 and the pipe connecting portions 40 which are necessary for the installation construction work and the maintenance can be exposed to outside.
Ends of respective pipes of the pipe connecting portions 40 are directed downward. According to this, the pipes connected to the pipe connecting portions 40 can easily be connected to the pipe connecting portions 40 from their lower sides.
Since the control device 21 and the pipe connecting portions 40 are placed at the positions opposed to the inner surface of the front surface panel 29a as described above, the control device 21 and the pipe connecting portions 40 can be exposed to outside only by detaching the front surface panel 29a. Frequency of use in the maintenance of the control device 21 and the pipe connecting portions 40 is lower than that of the overpressure relief valve 11 and the air vent valve 17, and it is unnecessary for a user to directly touch the control device 21 and the pipe connecting portion 40. Therefore, if these members are placed on the side of the inner surface of the front surface panel 29a, these members are kept out of user's sight. Therefore, appearance is enhanced. Further, for an installation operator, the control device 21 and the pipe connecting portions 40 can easily be exposed only by detaching the front surface panel 29a at the time of the installation construction work or the maintenance. Therefore, the installation performance and the maintenance performance are enhanced.
Since the pipe connecting portions 40 are provided at positions lower than the control device 21, even when heat medium or water leaks when the pipes are connected, it is possible to prevent the control device 21 from being touched. Further, since the pipe connecting portions 40 are disposed at positions having the predetermined height L from the installed surface of the hot water tank unit 2, when the hot water tank unit 2 is installed, it is possible to carry out the installation construction work without regard to the ceiling in the installation space, and it becomes easy to connect the pipes.
As shown in Fig. 5, the water-refrigerant heat exchanger 4 and the expansion tank 13 are placed in the hot water tank unit 2 and on the side of the upper surface panel 29b and the rear surface panel 29d. The circulation pump 9 and the three-way valve 16 are placed closer to the front surface panel 29a than the water-refrigerant heat exchanger 4 and the expansion tank 13. The heater portion 14, the overpressure relief valve 11 and the air vent valve 17 are placed forward of the circulation pump 9 and the three-way valve 16. The air vent valve 17 is placed at the highest side of the heat medium path 12a.
The overpressure relief valve 11 and the air vent valve 17 are mounted to upper portions of the heater portion 14. A flow path cross-sectional area of heat medium of the heater portion 14 is greater than that of the other heat medium path 12a. Hence, if the overpressure relief valve 11 is mounted on the heater portion 14, it is possible to reliably reduce the internal pressure of the heat medium path 12a. Further, a flow path cross-sectional area of heat medium of the heater portion 14 is greater than that of the other heat medium path 12a. Therefore, in the heater portion 14, air easily moves upward in accordance with its buoyance. Therefore, by mounting the air vent valve 17 on the heater portion 14, it is possible to collect air existing in the heat medium circuit 12 to the air vent valve 17, and to easily discharge the air to outside of the heat medium circuit 12. If the air vent valve 17 is provided at the highest portion of the heat medium circuit 12, it is possible to easily vent air in the heat medium circuit 12.
The hot water tank 15 is placed at a location lower than the water-refrigerant heat exchanger 4, the circulation pump 9, the expansion tank 13, the heater portion 14 and the three-way valve 16. The hot water tank 15 is covered with the heat insulator. The partition plate 39 is provided between the hot water tank 15 and, the water-refrigerant heat exchanger 4, the circulation pump 9, the expansion tank 13, the heater portion 14 and the three-way valve 16. The partition plate 39 is connected and fixed to the side surface panels 29c or the frame body.
The water-refrigerant heat exchanger 4 and the expansion tank 13 are connected and fixed to the casing 29 (rear surface panel 29d in this embodiment) and the partition plate 39. The water-refrigerant heat exchanger 4 and the expansion tank 13 are heavy in weight. Therefore, if they are connected to both the casing 29 and the partition plate 39, they can be fixed strongly.
The circulation pump 9 and the three-way valve 16 are connected and fixed to the partition plate 39. If the circulation pump 9 is driven, the circulation pump 9 generates vibration, but since the circulation pump 9 is strongly fixed to thee partition plate 39, it is possible to suppress the vibration, and even if vibration is generated, it transmits to the partition plate 39 and the vibration diffuses to the entire casing 29. Therefore, it is possible to restrain noise caused by vibration from generating.

[INDUSTRIAL APPLICABILITY]

As described above, according to the present invention, it is possible to provide a space-saving hot water generator having excellent installation performance and maintenance performance. The hot water generator can be applied to a water heater, a hot water heater and the like.

[EXPLANATION OF SYMBOLS]

1: heat pump unit
2: hot water tank unit
3: compressor
4: water-refrigerant heat exchanger
5: decompressor
6a: evaporator
8: refrigerant pipe
8a, 8b: refrigerant connecting portion
11: overpressure relief valve
12: heat medium circuit
12a: heat medium path
12b: bypass path
15: hot water tank
15a: heat exchanger
17: air vent valve
19: heater terminal
20: heat medium pipe
20a, 20b: heater connecting portion
21: control device
22: remote control
23: pressure gauge
25: operating portion cover
29: casing
29a: front surface panel
29e: operating portion panel
30a, 30b: hot water supply connecting portion
40: pipe connecting portion

Claims

A hot water generator comprising:
a heat pump device formed by annularly connecting, to one another through refrigerant pipes, a compressor, a water-refrigerant heat exchanger, a decompressor and an evaporator;

a heat medium path through which heat medium heated by the water-refrigerant heat exchanger flows;

a hot water tank in which heat medium or hot water heated by the heat medium is stored;

an overpressure relief valve for releasing pressure in an interior of the heat medium path when this pressure becomes equal to or higher than predetermined pressure;

an air vent valve for venting air in the interior of the heat medium path; and

a casing in which at least the water-refrigerant heat exchanger, the heat medium path, the hot water tank, the overpressure relief valve and the air vent valve are accommodated, wherein

the casing is provided with an operating portion cover which can open and close, or can attach and detached, and

the overpressure relief valve and the air vent valve are placed on an inner side of the operating portion cover.
The hot water generator according to claim 1, further comprising a pressure gauge for measuring the pressure in the interior of the heat medium path, and
a remote control having a function to adjust temperature of the heat medium or the hot water, wherein
the pressure gauge and the remote control are placed on the inner side of the operating portion cover.
The hot water generator according to claim 1 or 2, wherein the operating portion cover is provided at a location higher than a central location in a height direction of the casing.
The hot water generator according to claim 1 or 2, further comprising:
a heat pump unit including the compressor, the water-refrigerant heat exchanger, the decompressor and the evaporator; and

a hot water tank unit including the water-refrigerant heat exchanger, the heat medium path and the hot water tank, wherein
the hot water tank unit is provided with a refrigerant connecting portion to which the refrigerant pipe to be connected to the heat pump unit is connected, and a heater connecting portion to which a heat medium pipe for supplying the heat medium to a heater terminal is connected,
a front surface panel configuring the casing is provided below the operating portion cover, and
the refrigerant connecting portion and the heater connecting portion are placed on an inner side of the front surface panel.
The hot water generator according to claim 3, further comprising:
a heat pump unit including the compressor, the water-refrigerant heat exchanger, the decompressor and the evaporator; and

a hot water tank unit including the water-refrigerant heat exchanger, the heat medium path and the hot water tank, wherein
the hot water tank unit is provided with a refrigerant connecting portion to which the refrigerant pipe to be connected to the heat pump unit is connected, and a heater connecting portion to which a heat medium pipe for supplying the heat medium to a heater terminal is connected,
a front surface panel configuring the casing is provided below the operating portion cover, and
the refrigerant connecting portion and the heater connecting portion are placed on an inner side of the front surface panel.