EP1965145A1

EP1965145A1 - Heat pump hot-water supply device

Info

Publication number: EP1965145A1
Application number: EP06833808A
Authority: EP
Inventors: Etsuo Shibata
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2005-12-08
Filing date: 2006-11-30
Publication date: 2008-09-03
Also published as: WO2007066579A1; EP1965145A4

Abstract

In a heat pump water heater, a water-cooling heat exchanger is comprised for preliminarily cooling water, that flows into a water-heating heat exchanger for heating the water by a heat exchange with a refrigerant, by performing a heat exchange with a refrigerant, to prevent water from freezing in the water-cooling heat exchanger. A refrigerant temperature sensor 13 for detecting the temperature of the refrigerant discharged from a water-heating heat exchanger 3, and a water-cooling heat exchanger 5 for performing the heat exchange between the refrigerant flowing from an expander 15 toward a compressor 11 and the water supplied from a storage tank 4 are comprised, so that the flow amount of the refrigerant toward the water-cooling heat exchanger 5 is adjusted on the basis of the refrigerant temperature detected by the refrigerant temperature sensor 13. For example, the expander 15 is closed when the temperature detected by the refrigerant temperature sensor 13 is lower than a prescribed temperature.

Description

BACKGROUND OR THE INVENTION

Field of the Invention

The present invention relates to a heat pump water heater for supplying hot water by heating water by means of heat exchange with a refrigerant, which is circulating in a refrigerant circulations channel provided with a compressor or an expander, and more particularly, to a technology for improving the energy consumption efficiency (COP : Coefficient Of Performance) of the heat pump water heater.

Description or the Related Art

Generally, a heat pump water heater, which comprises a water-heating heat exchanger (corresponding to a first water heat exchanger) for heating the water by heat exchange with a refrigerant circulating in a refrigerant circulation channel provided with a compressor or an expander, and stores the hot water hcatcd by the water-heating heat exchanger in a storage tank to supply the hot water inside of the storage tank as need arises, is well-known. Additionally, stacked in the upper layer inside of the storage tank is the hot water at high temperature that is heated by the water-heating heat exchanger, and stacked in the lower layer thereof is the water at low temperature supplied from city water. In the heat pump water heater, a water flow channel is provided such that the water at low temperature stored in the lower layer of the storage tank is heated by the water-heating heat exchanger, before being stacked in the upper layer of the storage tank.
And also, the heat pump water heater is often connected with a heating circuit for floor heating which employs hot water at high temperature stored in the storage tank as a heating medium, or with a reheating circuit for a bath (for example, see Patent literature 1: Japanese Unexamined Patent Application Publication No. 2004-211986 ).
Fig. 8 schematically shows a configuration of a conventional heat pump water heater.
As shown in Fig. 8, the conventional heat pump water heater comprises a refrigerant circuit 85 in which a compressor 81, a water-heating heat exchanger 82, a throttle mechanism (expander) 83, and an outdoor air heat exchanger 84 are sequentially connected, and a water circuit 88 that runs from the lower part in the storage tank 86, passing through a circulation pump 87 and the water-heating heat exchanger 82, and pouring into the upper part in the storage tank 86. A heater 92 and a hot water supply port 94 both having a heat exchanger for heating 90 in their circuits are provided in the load side of the heat pump water heater.
Hereinafter, the performance of the thus configured conventional heat pump water heater is explained.
In the refrigerant circuit 85, the refrigerant having high temperature and high pressure and discharged from the compressor 81 flows in the direction shown with an arrow, and gives the water heat in the water-heating heat exchanger 82. After that, the pressure of the refrigerant is reduced by the throttle mechanism 83 to decrease its temperature. The refrigerant then absorbs heat from the air in the outdoor air heat exchanger 84, and returns to the compressor 81. On the other hand, in the water circuit 88, the water flows into the water-heating heat exchanger 82 from the lower part of the storage tank 86 using the circulation pump 87 along the direction shown with an arrow, and then flows into the upper part of the storage tank 86 after increasing its temperature by absorbing the heat from the refrigerant in the refrigerant circuit 85. After that, the water is stacked in the upper part of the storage tank 86, so that the water having high temperature is stored in the storage tank 86.
In the load side, when the hot water supply port 94 is opened, the water at high temperature stored in the upper part of the storage tank 86 is pushed out by the water flowing to the lower part of the storage tank 86 from the water supply port 95 by means of the water pressure, and therefore, flows in the direction shown with an arrow to be supplied to the outside. In the water circuit in the side of the heater 92, the water at high temperature and discharged from the upper part of the storage tank 86 by means of a primary-side circulation pump for heating 91 flows into the direction shown with an arrow, and then flows into the lower part of the storage tank 86 after giving its heat to a heating brine in the heat exchanger for heating 90. On the other hand, the heating brine is circulated in the direction shown with an arrow by means of a secondary-side circulation pump for heating 93, and then releases the heat, that has been given in the heat exchanger for heating 90, in the heater 92 to perform heating.
However, the conventional heat pump water heater configured as mentioned above still has the following problems.
When heating operation is conducted, the water having high temperature and flowing out from the upper part of the storage tank 86 decreases its temperature for about 10 to 20 degrees centigrade by releasing its heat in the heat exchanger for heating 90, however, the water at relatively high temperature flows into the lower part of the storage tank &6. Meanwhile, the refrigerant circuit 85 in the heat pump cycle therefore heats the water having slightly high temperature in the lower part of the storage tank 86, resulting in the operation at a low COP (coefficient of performance). For example, the COP for heating water at 15 degrees centigrade up to 65 degrees centigrade is about 3 to 4, however, the COP for heating water at slightly high temperature of 45 degrees centigrade up to 65 degrees centigrade is about 1 to 2, and thus, the operation has to be conducted at a rather low efficiency. And also, as the temperature of the water to be heated rises higher, the pressure discharged from the compressor 81 rises too high in the refrigerant circuit 85 in the heat pump cycle, and the operation has therefore been impossible.
On the other hand, it can be understood that a water-cooling heat exchanger (corresponding to a second water heat exchanger), that cools the mid-temperature hot water by a heat exchange with a refrigerant at a low temperature flowing from a water-heating heat exchanger through a expander, is provided in a refrigerant circuit (for example, Patent literature 1: Japanese Unexamined Patent Application Publication No. 2004-211986 ). In such configuration, the heat exchange efficiency of the water-heating heat exchanger can be improved by flowing the above mentioned mid-temperature hot water, that once has been cooled at the water-cooling heat exchanger, into the water-heating heat exchanger.
However, when the temperature of the refrigerant flowing from the water-heating heat exchanger into the water-cooling heat exchanger through the expander is low enough to freeze the water flowing from the storage tank into the water heat exchanger by means of the heat exchange, the water flowing into the water-cooling heat exchanger may freeze, damaging the water-cooling heat exchanger as well as a water flow channel.
In view of the above problem residing in the prior arts, it is an object of the present invention to provide a heat pump water heater, which comprises a water-cooling heat exchanger for preliminarily cooling down the water, that flows into a water-heating heat exchanger to be heated by heat exchange with a refrigerant, by performing the heat exchange with a refrigerant in order to prevent the water from freezing in the water-cooling heat exchanger.

SUMMARY OF THE INVENTION

In order to achieve the above goal, a heat pump water heater according to the present invention comprises:

a refrigerant circulation channel in which a refrigerant is circulated, a water flow channel in which water flows, a first water heat exchanger for conducting the heat exchange between the refrigerant discharged from a compressor in the refrigerant circulation channel and the water flowing in the water flow channel, a storage tank for storing the water having been discharged from the first water heat exchanger, an expander for expanding the refrigerant having been discharged from the first water heat exchanger, an outdoor air heat exchanger for conducting heat exchange between the refrigerant flowing from the expander to the compressor and outdoor air, and a second water heat exchanger for conducting heat exchange between the refrigerant flowing from the expander to the compressor and the water supplied from the storage tank,

According to the thus configured present invention, adjusting the flow and the flow amount of the refrigerant toward the second water heat exchanger on the basis of the temperature of the present refrigerant enables the water to be prevented from freezing in the present second water heat exchanger. Consequently, damages of such as the second water heat exchanger and the water flow channel can be prevented. When there is no possibility for the water to freeze in the second water heat exchanger, it is needless to say that the energy consumption efficiency in the present heat pump water heater can be prevented from decreasing, since the water discharged from the storage tank can be cooled in the second water heat exchanger before flowing into the first water heat exchanger.
More specifically, when the temperature of the refrigerant discharged from the expander is the one at which the water clots (freezes) from the heat exchange with the refrigerant, the flow of the refrigerant toward the second water heat exchanger may be blocked.
Here, the expander may comprise a first expander for discharging the refrigerant toward the outdoor air heat exchanger and a second expander for discharging the refrigerant toward the second water heat exchanger. In this case, the temperatures of the refrigerant discharged from the first expander and from the second expander are detected, and, based on these detection results, the flow and the flow amount of the refrigerant toward the second water heat exchanger may be adjusted.
And also, the second expander may be simply and inexpensively configured by comprising a solenoid valve for adjusting the flow of the refrigerant from the first water heat exchanger toward the second water heat exchanger, and a capillary tube for expanding the refrigerant flowing from the solenoid valve toward the second water heat exchanger. In this case, the flow amount of the refrigerant, that flows from the first water heat exchanger toward the second water heat exchanger by the control of the solenoid valve, is not controlled, while on the other hand, the existence of the refrigerant flow toward the second water heat exchanger is controlled.
Additionally, the flow of the refrigerant toward the second water heat exchanger, in other words, the cooling down of the water discharged from the storage tank in the second water heat exchanger, is necessary when the temperature of the water is high. And so, a desirable configuration is to comprise a first water temperature detection means for detecting the temperature of the water discharged from the storage tank. And the flow and/or the flow amount of the refrigerant toward the second water heat exchanger may therefore be adjusted on the basis of the water temperature detected by the first water temperature detection means.
More specifically, the refrigerant may flow into the second water heat exchanger on condition that the water temperature detected by the first water temperature detection means is higher than or equal to a first prescribed temperature, while on the other hand, the flow of the refrigerant toward the second water heat exchanger may be blocked on condition that the water temperature detected by the first water temperature detection means is lower than the first prescribe temperature. This enables the water discharged from the storage tank to be cooled in the second water heat exchanger before flowing into the first water heat exchanger according to need.
Moreover, it is desirable to comprise a second water temperature detection means for detecting the temperature of the water flowing into the first water heat exchanger, so that whether or not the water discharged from the storage tank is sufficiently cooled in the second water heat exchanger is judged. Additionally, in this case, the flow and/or the flow amount of the refrigerant toward the second water heat exchanger is adjusted on the basis of the water temperature detected by the second water temperature detection means, so that the temperature of the water flowing into the first water heat exchanger can he properly adjusted.
More specifically, the flow amount of the refrigerant toward the second water heat exchanger may be increased on condition that the water temperature detected by the second water temperature detection means is higher than or equal to a second prescribed temperature, while on the other hand, the flow amount of the refrigerant toward the second water heat exchanger may be decreased on condition that the water temperature detected by the second water temperature detection means is lower than a third prescribed temperature that is lower than the second prescribed temperature.
When the water flow channel comprises a first water flow channel connected from the storage tank, through the first water heat exchanger, and back to the storage tank, and a second water flow channel connected sequentially from the storage tank, through the second water heat exchanger, the first water heat exchanger, and back to the storage tank, the distribution amount of the water to be supplied from the storage tank to the first water flow channel and the second water flow channel may be adjusted on the basis of the water temperatures detected by the first and second water temperature detection means. In such configuration, the temperature of the water flowing into the first water heat exchanger may also be properly adjusted.
More specifically, on condition that the water temperature detected by the first water temperature detection means is higher than or equal to a fourth prescribed temperature, the water may be distributed by the water distributor to the second water flow channel. And also, the water amount to be distributed by the water distributor to the second water flow channel may be increased, on condition that the water temperature detected by the second water temperature detection means is higher than or equal to a fifth prescribed temperature, while on the other hand, the water amount to be distributed by the water distributor to the second water flow channel may be decreased, on condition that the water temperature detected by the second water temperature detection means is equal to or lower than a sixth prescribed temperature that is lower than the fifth prescribed temperature.
In addition, even with the heat pump water heater disclosed in Patent literature 1: Japanese Unexamined Patent Application Publication No. 2004-211986 , the problems in operating such as a hot water heating unit have not been sufficiently solved, and there always has been a limit for an efficient operation thereof. In response, the present invention provides a heat pump water heater, which not only consumes the obtained hot water by providing it to the outside, but also uses the hot water for such as heating, thereby realizing an efficient operation.
A heat pump water heater according to one aspect of the present invention comprises a refrigerant circulation channel for circulating a refrigerant and a water flow channel for flowing the water. In the refrigerant circulation channel, the followings are sequentially connected: a compressor, a first water heat exchanger for providing water in the water flow channel with heat from the refrigerant in the refrigerant circulation channel, a throttle mechanism, an outdoor air heat exchanger for providing the refrigerant in the refrigerant circulation channel with heat from the external air, and a second water heat exchanger for providing heat with the refrigerant in the refrigerant circulation channel from the water in the water flow channel. In the water flow channel, a storage tank, a circulation pump, the second water heat exchanger, and the first water heat exchanger are sequentially connected.
In addition, a heat pump water heater according to another aspect of the present invention comprises a refrigerant circulation channel for circulating a refrigerant and a water flow channel for flowing the water. In the refrigerant circulation channel, the followings are sequentially connected: a compressor, a first water heat exchanger for providing the water in the water flow channel with heat from the refrigerant in the refrigerant circulation channel, a throttle mechanism, an outdoor air heat exchanger for providing the refrigerant in the refrigerant circulation channel with heat from the external air, and a second water heat exchanger for providing the refrigerant in the refrigerant circulation channel with heat from the water in the water flow channel. The water flow channel includes a first water flow channel and a second water flow channel. In the first water flow channel, a storage tank, a circulation pump, a switching valve for switching the flow channel between the first water flow channel and the second water flow channel, and a first water heat exchanger are sequentially connected. In the second water flow channel, a storage tank, a circulation pump, the switching valve, the second water heat exchanger, and the first water heat exchanger are sequentially connected.
A heat pump water heater according to another aspect of the present invention comprises a first water temperature detection means for detecting the temperature of the water flowing out from the storage tank. When the water temperature detected by the first water temperature detection means is higher than a preset temperature, the flow channel is switched to the second water flow channel by the switching valve.
In addition, a heat pump water heater according to another aspect of the present invention comprises a first water temperature detection means for detecting the temperature of the water flowing out from the storage tank and a second water temperature detection means for detecting the temperature of the water flowing into the first water heat exchanger. When the water temperature detected by the first water temperature detection means is higher than a preset temperature, at least a part of the flow channel is switched to the second water flow channel by the switching valve. When the water temperature detected by the second water temperature detection means is lower than a preset temperature, the switching valve is controlled so that the flow amount into the first water flow channel is greater, and on the other hand, when the water temperature detected by the second water temperature detection means is higher than a preset temperature, the switching valve is controlled so that the flow amount into the second water flow channel is greater.
As described above, according to the present invention, when the water at a slightly high temperature and flowing out from the storage tank is heated, the water flowing out from the storage tank and being flowed in the water flow channel is cooled with the refrigerant in the refrigerant circulation channel in the second water heat exchanger before being heated with the refrigerant in the refrigerant circulation channel in the first water heat exchanger, while on the other hand, the refrigerant in the refrigerant circulation channel is heated with the external air in the outdoor air heat exchanger before being additionally heated with the water in the water flow channel in the second water heat exchanger. Consequently, the heat pump water heater can operate without excessively increasing the pressure discharged from the compressor in the refrigerant circulation channel of the heat pump cycle, and at the same time, can efficiently operate without reducing COP.
The present invention can prevent the water from freezing in the second water heat exchanger, by adjusting the flow and/or the flow amount of the refrigerant toward the second water heat exchanger on the basis of the temperature of the refrigerant. Consequently, damages in the second water heat exchanger and the water flow channel can be prevented. When there is no doubt the water does not freeze in the second water heat exchanger, the energy consumption efficiency of the present heat pump water heater can be prevented from reducing, since the water discharged from the storage tank can be cooled in the second water heat exchanger before flowing into the first water heat exchanger.

BREIF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a block diagram showing a general structure of a heat pump water heater according to the embodiment of the present invention:
Fig. 2 is a flow chart explaining an example of the procedure for the adjusting process of the refrigerant flow which is conducted in a heat pump water heater according to the embodiment of the present invention;
Fig. 3 is a block diagram showing a variation of an expander 15;
Fig. 4 is a flow chart illustrating another example of the adjusting process of the refrigerant flow;
Fig. 5, is a block diagram showing a general structure of a heat pump water heater according to Example 2 of the present invention;
Fig. 6 is a flow chart explaining one example of the procedure for the adjusting process of the water flow amount which is conducted in a heat pump water heater according to Example 2 of the present invention;
Fig. 7 is a block diagram showing a general structure of a heat pump water heater according to Example 4 of the present invention;
Fig. 8 is a block diagram showing a general structure of a conventional heat pump water heater.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In what follows, an embodiment of the present invention is described as referring to the accompanied figures in order to provide sufficient understanding. In addition, the following embodiment is a mere example of realizing the present invention, having no intention to limit the spirit and scope of the present invention.
Fig. 1 is a block diagram showing a general structure of a heat pump water heater X1 according to the embodiment of the present invention, and Fig. 2 is a flow chart explaining an example of the procedure for the adjusting process of the refrigerant flow which is conducted in the heat pump water heater X1.
Firstly, as referring to Fig. 1, the general structure of a heat pump water heater X1 according to the embodiment of the present invention is described.
As shown in Fig. 1, the heat pump water heater X1 is generally configured by comprising: a refrigerant circuit 1 (one example of a refrigerant circulation channel) in which a refrigerant is circulated, a hot water supply circuit 2 in which water is flowed (one example of a water flow channel), a water-heating heat exchanger 3 (one example of a first water heat exchanger) for heating the water by performing the heat exchange between the refrigerant circulated in the refrigerant circuit 1 and the water flowed in the hot water supply circuit 2, a storage tank 4 for storing the hot water has been heated by the water-heating heat exchanger 3, a water-cooling heat exchanger 5 (one example of a second water heat exchanger) for cooling the water by performing the heat exchange between the refrigerant circulated in the refrigerant circuit 1 and the water flowed in the hot water supply circuit 2, and a heating cycle 6 (one example of a heating cycle) that employs hot water stored in the storage tank 4 as a heating medium. The heat pump water heater X1 (the later described heat pump water heaters X2 to X4) also comprises a controller having such as CPU, RAM, ROM (not shown), thereby being controlled integrally.
In addition, the water at low temperature (for example, at 15 degrees centigrade) supplied from the water supply port via a water channel 41 is stored in the lower layer of the storage tank 4, while the hot water at high temperature (for example, at 65 degrees centigrade) heated in the water-heating heat exchanger 3 is stored in the upper layer thereof. The hot water at high temperature stored in the upper layer in the storage tank 4 is discharged to the hot water supply port from the storage tank 4 via a water channel 42, upon opening of the hot water supply cock 43 provided in the water channel 42.
The refrigerant circuit 1 comprises: a refrigerant circuit 1a, in which the refrigerant is circulated sequentially from a comprcssor 11, the water-heating heat exchanger 3, an expander 12 (one example of an expander), a refrigerant temperature sensor 13 (one example of a refrigerant temperature detection means), an outdoor air heat exchanger 14, and back to the compressor 11, and a refrigerant circuit 1b, in which the refrigerant is circulated sequentially from the compressor 11, the water heating heat exchanger 3, an expander 15 (one example of the second expander), the water-cooling heat exchanger 5, and back to the compressor 11. In addition, the expanders 12 and 15 may be integrated into one expander.
In the refrigerant circuit 1, the refrigerant discharged from the water-heating heat exchanger 3 is dispensed by the expanders 12 and 15 so as to flow into the outdoor air heat exchanger 14 and the water-cooling heat exchanger 5 respectively for distribution, before joining together and flowing into the compressor 11. In short, the outdoor air heat exchanger 14 and the water-cooling heat exchanger 5 are connected in parallel.
The expander 12 includes a flow amount adjustment mechanism for adjusting the flow and/or the flow amount of the refrigerant flowing from the water-heating heat exchanger 3 toward the outdoor air heat exchanger 14, and an expansion mechanism for expanding the refrigerant flowing from the water-heating heat exchanger 3 toward the outdoor air heat exchanger 14.
And the expander 15 also includes a flow amount adjustment mechanism for adjusting the flow and/or the flow amount of the refrigerant flowing from the water-heating heat exchanger 3 toward the water-cooling heat exchanger 5, and an expansion mechanism for expanding the refrigerant flowing from the water-heating heat exchanger 3 toward the water-cooling heat exchanger 5.
The refrigerant temperature sensor 13 is one example of the refrigerant temperature detection means composed of such as a thermistor, and detects the temperature of the refrigerant discharged from the expander 12. Here, the temperature of the refrigerant detected by the refrigerant temperature sensor 13 is almost the same level as the one of the refrigerant, that is discharged from the expander 15 and flowing into the water-cooling heat exchanger 5. The temperature of the refrigerant detected by the refrigerant temperature sensor 13 is input into the controller. The temperature of the refrigerant detected by the refrigerant temperature sensor 13 is employed as a judgment index in the later-described adjusting process of the refrigerant flow (see the flow chart in Fig. 2).
And also, an existing, built-in temperature sensor in the outdoor air heat exchanger 14 may be employed as the refrigerant temperature sensor 13. Here, the outdoor air heat exchanger 14 conducts the heat exchange between the outdoor air blown in by a blower fan 14a provided in an outdoor unit (not shown) along with the outdoor air heat exchanger 14 and the refrigerant discharged from the expander 12.
In the refrigerant circuit 1, the refrigerant is circulated along with the rotation of the compressor 11 by the controller.
Here, in the refrigerant circuit 1a, the refrigerant at high temperature and high pressure discharged after compressed by the compressor 11 is cooled by the heat exchanger with the water flowing on the hot water supply circuit 2 in the water-heating heat exchanger 3, and then expands in the expander 12. After that, the refrigerant at low temperature and low pressure expanded by the expander 12 absorbs heat by means of the heat exchange with the outdoor air in the outdoor air heat exchanger 14 in order to evaporate, and then joins together with the refrigerant in the refrigerant circuit 16, before flowing again into the compressor 11 (the directions indicated with solid arrows in the present figure).
On the other hand, in the refrigerant circuit 1b, the refrigerant at high temperature and high pressure discharged after compressed by the compressor 11 is cooled by the heat exchange with the water flowing on the hot water supply circuit 2 in the water-heating heat exchanger 3, and then expands in the expander 15. After that, the refrigerant at low temperature and low pressure expanded by the expander 15 absorbs heat in the water-cooling heat exchanger 5 by means of the heat exchange with the water flowed in the hot water supply circuit 2 in order to evaporate, and then joins together with the refrigerant in the refrigerant circuit 1 a, before flowing again into the compressor 11 (the directions indicated with dashed arrows in the present figure).
However, the controller's execution of the later-described adjusting process of the refrigerant flow (see the flow chart in Fig. 2) causes the flow and/or the flow amount of the refrigerant into the water-cooling heat exchanger 5 in the refrigerant circuit 1b to be adjusted.
The hot water supply circuit 2 is a water flow channel in which the followings are sequentially connected: a lower layer in the storage tank 4, a water temperature sensor 21 (one example of a first water temperature detection means), a circulation pump 22, the water-cooling heat exchanger 5, a water temperature sensor 23 (one example of a second water temperature detection means), the water-heating heat exchanger 3, a water temperature sensor 24, and an upper layer in the storage tank 4.
The water temperature sensor 21 detects temperature of the water discharged from the storage tank 4: the water temperature sensor 23 detects the temperatures of the water flows into the water-beating heat exchanger 5; and the water temperature sensor 24 detects the temperature of the water flowing into the storage tank 4, and these three sensors are composed of, for example, such as a thermistor. In addition, the water temperatures detected by the water temperature sensors 21, 23, and 24 are input into the controller.
In the hot water supply circuit 2, the drive of the circulation pump 22 by the controller causes the water to circulate. In the hot water supply circuit, upon driving the circulation pump 22, the water in the lower layer of the storage tank 4 is flowed up to the upper layer of the storage tank 4 sequentially through the water-cooling heat exchanger 5 and the water-heating heat exchanger 3. In this moment, the water' amount circulated by the circulation pump 22 is controlled by the controller so that the temperature detected by the water temperature sensor 24 settles to a preset temperature (for example, around 65 degrees centigrade). And also, in the heat pump water heater X1, the numbers of rotation of the compressor 11 and the circulation pump 22 are controlled by the controller so that the temperature detected by the water temperature sensor 24 settles to a preset temperature, and thereby adjusting the heating performance of the water-heating heat exchanger 3.
When the refrigerant is circulating in both the refrigerant circuits 1a and 1b in the refrigerant circuit 1 along with the drive of the compressor 11, the water supplied from the lower layer in the storage tank 4 and flowed on the hot water supply circuit 2 is cooled by the heat exchange with the refrigerant in the water-cooling heat exchanger 5, before being heated by the heat exchange with the refrigerant in the water-heating heat exchanger 3.
On the other hand, when the flow of the refrigerant toward the water-cooling heat exchanger 5 is blocked in the refrigerant circuit 1b by the controller's adjustment of the open level of the expander 15, the water supplied from the lower layer in the storage tank 4 and flowed on the hot water supply circuit 2 flows into the water-heating heat exchanger 3 just as its temperature is and is heated by the heat exchange with the refrigerant, without being cooled by the heat exchange with the refrigerant in the water-cooling heat exchanger 5.
The hot water heated up to high temperature (for example, around 65 degrees centigrade) by the water-heating heat exchanger 3 is stored in the upper layer in the storage tank 4. The hot water at high temperature stored in the upper layer in the storage tank 4. is then discharged from the hot water supply port as need arises, or used as a heating medium for realizing heating operation in the heating cycle 6.
The heating cycle 6 includes a water circulation circuit 6a in which an upper layer in the storage tank 4, a water circulation pump 61, a heat exchanger for heating 62; and a lower layer in the storage tank 4 are sequentially connected, and a brine (antifreeze liquid) circulation circuit 6b in which a brine circulation pump 63, the heat exchanger for heating 62, and a heater 64 are sequentially connected.
The heater 64 is a floor heating device configured to comprise such as, for example, a floor heating panel, a radiation panel, and a hot air blower (not shown). In addition, the heating cycle 6 is not limited to the use in a floor heating device, and may be applied to various devices using hot water stored in the storage tank 4, such as a bath reheating device and an air conditioner.
In the water circulation circuit 6a, the controller's drive of the hot water circulation pump 61 causes the hot water at high temperature supplied from the upper layer in the storage tank 4 to reflow into the lower layer in the storage tank 4 via the heat exchanger for heating 62.
And also, in the brine circulation circuit 6b, the controller's drive of the brine circulation pump 63 causes the brine to circulate through the heat exchanger for heating 62 and the heater 64. This enables the brine circulating in the brine circulation circuit 6b to absorb heat by means of the heat exchange with the hot water on the water circulation circuit 6a in the heat exchanger for heating 62, and to release heat in the heater 64.
In this moment, the heat exchange with the brine in the heat exchanger for heating 62 causes the hot water at high temperature supplied from the upper layer in the storage tank 4 to decrease its temperature and reflow to the lower layer in the storage tank 4. Here, the temperature (for example, around 45 degrees centigrade) of the water reflowing to the lower layer of the storage tank 4 is lower than that of the hot water at high temperature (for example, around 65 degrees centigrade) stored in the upper layer in the storage tank 4, and at the same time, higher than that (for example, around 15 degrees centigrade) of the water supplied from the water supply port. Hereinafter, the hot water at relatively low temperature reflowing to the lower layer in the storage tank 4 is referred to as "mid-temperature hot water".
As described above, when the mid-temperature hot water flows into the water-heating heat exchanger 3 through the hot water supply circuit 2, the heat exchange efficiency between the refrigerant and the water in the water-heating heat exchanger 3 deteriorates. In response, in the heat pump water heater X1, when the temperature of the water to be supplied to the hot water supply circuit 2 from the lower layer in the storage tank 4 is equal to or higher than a preset temperature (for example, around 35 degrees centigrade), the execution of the later-described adjusting process of the refrigerant flow (see the flow chart in Fig. 2) by the controller enables the water to be controlled so as to be cooled in the water-cooling heat exchanger 5 before flowing into the water-heating heat exchanger 3. In this regard, however, when the water flowed in the hot water supply circuit 2 freezes in the water-cooling heat exchanger 5, such as the circulation pump 22 disposed in the water-cooling heat exchanger 5 or on the hot water supply circuit 2 might be damaged.
However, the heat pump water heater X1 according to the embodiment of the present invention enables the flow and/or the flow amount of the refrigerant toward the water-cooling heat exchanger 5 to be controlled on the basis of the temperature of the refrigerant flowing into the water-cooling heat exchanger 5 during the later-described adjusting process of the refrigerant flow that is to be executed by the controller, thereby preventing the water flowed in the hot water supply circuit 2 from freezing. Here, the controller at the execution of the adjusting process of the refrigerant flow corresponds to an adjusting means of the refrigerant flow.
In what follows, as referring to Fig. 1, one example of the procedure for the adjusting process of the refrigerant flow to be executed by the controller in the heat pump water heater X1 is explained in accordance with the flow chart in Fig. 2. In addition, S1, S2, and so on in the figure are representing the number of the process steps.
The controller conducts the adjusting process of the refrigerant flow at the time of starting the drive of the compressor I 1 and the circulation pump 22 in the heat pump water heater X1, and ends the same when these drives are stopped.
Firstly, in a step S1, the control of the expander 15 by the controller blocks the refrigerant flowing into the water-cooling heat exchanger 5 in the refrigerant, circuit 1b. More specifically, the close of the flow amount adjustment mechanism of the expander 15 upon adjustment thereof causes the refrigerant discharged from the water-heating heat exchanger 3 to be flowed only to the refrigerant circuit 1a, not dispensed to the refrigerant circuit 1b.
Next, in a step S2, the controller judges whether the temperature of the refrigerant detected by the refrigerant temperature sensor 13, in other words, the temperature of the refrigerant discharged from the expander 12 is equal to or lower than a preset temperature T1. As described above, the temperature of the refrigerant detected by the refrigerant temperature sensor 13 is almost the same level as the one of the refrigerant, that is discharged from the expander 15 and flows into the water-cooling heat exchanger 5. Additionally, when the flow of the refrigerant toward the water-cooling heat exchanger 5 is not blocked, a temperature detected by a refrigerant temperature detection sensor (not shown: one example of the refrigerant temperature detection means) provided so as to detect the temperature of the refrigerant discharged from the expander 15, other than the refrigerant temperature detection sensor 13, may be employed. And also, both temperatures of the refrigerant discharged from each of the expanders 12 and 15 may be detected and used.
Here, the preset temperature T1 is the information previously stored in such as a ROM in the controller, and is an example of the temperature at which the water freezes from the heat exchange between the refrigerant and the water in the water-cooling heat exchanger 5. The preset temperature T1 may be set around, for example, -15 degrees centigrade. In addition, the freeze of the water in the water-cooling heat exchanger 5 depends on the temperature of the water flowing into the water-cooling heat exchanger 5, and thus, as another embodiment, the preset temperature T1 may be previously set to the refrigerant temperature at which the water at, for example, 15 degrees centigrade freezes, and changed according to the water temperature detected by the water temperature sensor 21.
In the step S2, during the time when the refrigerant temperature detected by the refrigerant temperature sensors 13 is being judged as less than the preset temperature T1 ("No" in S2), the judging process of the S2 is repeated.
In short, when the refrigerant temperature is the one at which the water being flowed in the hot water supply circuit 2 may possibly freeze (clot), the refrigerant flow into the water-cooling heat exchanger 5 in the refrigerant circuit 1 b is blocked, so that the refrigerant keeps on circulating only in the refrigerant circuit 1a.
This enables the water supplied from the lower layer in the storage tank 4 to be distributed in the hot water supply circuit 2 to flow into the water-heating heat exchanger 3 just as its temperature is without being cooled in the water-cooling heat exchanger 5, and therefore, the water is heated by the heat exchange with the refrigerant circulating in the refrigerant circuit 1a in the water-heating heat exchanger 3. Consequently, in the heat pump water heater X1, damages of such as the water-cooling heat exchanger 5 and the circulation pump 22 can be prevented, since the water being distributed on the hot water supply circuit 2 in the water cooling heat exchanger 5 does not freeze.
On the other hand, in the step S2, when the refrigerant temperatures detected by the refrigerant temperature sensor 13 is judged as being equal to or higher than the preset temperature T1 ("Yes" in S2), there is no possibility for the water distributed on the hot water supply circuit 2 in the water-cooling heat exchanger 5 to freeze from the heat exchange with the refrigerant. In this case, the process proceeds to the step S3.
In the following step S3, the controller judges whether the water temperature detected by the water temperature sensor 21, in short, the temperature of the water supplied from the lower layer in the storage tank 4 to the hot water supply circuit 2 is equal to or higher than a preset water temperature t1 (one example of a first prescribed temperature). Here, the preset water temperature t1 is the information previously stored in such as a ROM in the controller, and at which the heat exchange efficiency between the refrigerant and the water in the water-heating heat exchanger 3 deteriorates. The preset water temperature t1 is set around, for example, 35 degrees centigrade. Additionally, the preset water temperature t1 is desired to be changeable according to an input from an operation unit not shown. The controller conducts this changing process.
Here, in the step S3, when the water temperature detected by the water temperature sensor 21 is judged as being less than the preset water temperature t1 ("No" in S3), the heat exchange efficiency in the water-heating heat exchanger 3 does not deteriorate. And thus, there is no need for the water supplied from the storage tank 4 to the hot water supply circuit 2 to be cooled before flowing into the water-heating heat exchanger 3. In this case, the process moves back to the step S1, and the refrigerant flowing into the refrigerant circuit 1b is blocked, so that the refrigerant keeps on flowing only into the refrigerant circuit 1a
On the other hand, in the step S3, when the water temperature detected by the water temperature sensor 21 is judged as being equal to or higher than the preset water temperature t1 ("Yes" in S3), the heat exchange efficiency in the water-heating heat exchanger 3 may deteriorate. In this case, the process proceeds to the step S4.
In the following step S4, to control the expander 15 by the controller allows the refrigerant to begin to flow into the water-cooling heat exchanger 5 in the refrigerant circuit 1b. More specifically, adjusting the open level of the flow amount adjustment mechanism in the expander 15 causes the refrigerant discharged from the water-heating heat exchanger 3 to be dispensed to the refrigerant circuit 1a and the refrigerant circuit 1b for flow. In the hot water supply circuit 2, this allows the mid-temperature hot water supplied from the lower layer in the storage tank 4 to be cooled in the water-cooling heat exchanger 5 before flowing into the water-heating heat exchanger 3.
As mentioned above, in the heat pump water heater X1, the flow amount, more specifically, the existence of the flow of the refrigerant toward the water-cooling heat exchanger 5 is controlled base on the water temperature detected by the water temperature sensor 21. Consequently, even when mid-temperature hot water is supplied from the storage tank 4 to the refrigerant circuit 1b, such as when the use of the heating cycle 6 in the heating operation causes the mid-temperature hot water to reflow to the inside of the storage tank 4, the heat exchange efficiency in the water-heating heat exchanger 3 is improved, thereby preventing the deterioration of the energy consumption efficiency in the present heat pump water heater X1..
In addition, the default value of the flow amount of the refrigerant toward the water-cooling heat exchanger 5 in the refrigerant circuit 1b is previously set, however, in the adjusting process of the refrigerant flow, the flow amount of the refrigerant in the following is changed after a step S5 in the latter part.
In the step S5, the controller judges whether the water temperature detected by the water temperature sensor 23, in short, the water temperature of the water flowing into the water-heating heat exchanger 3 is equal to or higher than a preset water temperature t2 (one example of a second prescribed temperature). Here, the preset water temperature t2 is the information previously stored in such as a ROM in the controller, and at which the heat exchange efficiency between the refrigerant and the water in the water-heating heat exchanger 3 deteriorates. The preset water temperature t2 is set around, for example, 35 degrees centigrade. In short, in the step S5, it is judged whether or not the water flowing into the water-heating heat exchanger 3 is cooled down to the temperature at which the heat exchange efficiency in the water-heating heat exchanger 3 does not decrease. Additionally, the preset water temperature t2 is desired to be changeable according to an input from an operation unit not shown. This changing process is conducted by the controller.
Firstly, the following describes a case where the water temperature detected by the water temperature sensor 23 is judged as being less than the preset water temperature t2 ("No" in S5).
In this case, the water flowing into the water-hcating heat exchanger 3 is in a state that it is cooled down to the temperature, at which the heat exchange efficiency in the water-heating heat exchanger 3 does not decrease. In short, the cooling performance in the water-cooling heat exchanger 5 is sufficient in this state. Hence, the process proceeds to a step SS without changing the amount of the refrigerant flowing into the water-cooling heat exchanger 5.
In the step S51, the controller judges whether the water temperature detected by the water temperature sensor 23 is equal to or lower than a preset water temperature t3 (one example of the third prescribed temperature). Here, the preset water temperature t3 is the information previously stored in such as a ROM in the controller, indicating that the heat exchange efficiency between the refrigerant and the water in the water-heating heat exchanger 3 is sufficient, and that the water on the hot water supply circuit 2 is being cooled bcyond necessity. More specifically, the preset water temperature t3 is set to a temperature lower than the preset water temperature t2 (for example, around 15 degrees centigrade).
Here, when the water temperature detected by the water temperature sensor 23 is judged as not being equal to or lower than the preset water temperature t3 ("No" in S51), the process goes back to the step S2, while on the other hand, when judged as being lower than the preset water temperature t3, the process proceeds to a step S52.
In the step S52, to control the expander 15 by the controller reduces the flow amount of the refrigerant toward the water-cooling heat exchanger 5 in the refrigerant circuit 1b by a prescribed value. This deteriorates the cooling performance in the water-cooling heat exchanger 5, however, the flow amount of the refrigerant toward the outdoor air heat exchanger 14 in the refrigerant circuit I a increases correspondingly. Hence, the heat exchange performance in the outdoor air heat exchanger 14 improves, thereby increasing the supplying amount of hot water in the heat pump water heater X1. In addition, upon executing the step S52, the process goes back to the step S2.
The following describes a case where, in the step 85, the water temperature detected by the water temperature sensor 23 is judged as being equal to or higher than the preset water temperature t2 ("Yes" in S5).
In this case, the water flowing into the water-heating heat exchanger 3 is in a state that it is not cooled down to the temperature, at which the heat exchange efficiency in the water-heating heat exchanger 3 does not decrease. In short, the cooling performance in the water-cooling heat exchanger 5 is not sufficient in this state:
And thus, in the following step S6, to control the expander 15 by the controller increases the flow amount of the refrigerant toward the water-cooling heat exchanger 5 in the refrigerant circuit 1b by a prescribed value. This enhances the cooling performance in the water-cooling heat exchanger 5, and thus, the water flowing on the hot water supply circuit 2 is cooled down to a lower temperature before flowing into the water-heating heat exchanger 3. In addition, even if the refrigerant flow into the outdoor air heat exchanger 14 is blocked, the refrigerant circulating in the refrigerant circuit 1 can absorb heat by the heat exchange with the water on the hot water supply circuit 2 in the water-cooling heat exchanger 5. Thus, the refrigerant flow into the outdoor air heat exchanger 14 in the refrigerant circuit 1 a may be blocked.
As described above, in the adjusting process of the refrigerant flow, the distribution amount of the refrigerant to each of the refrigerant circuit 1a and the refrigerant circuit 1b in the refrigerant circuit, in other words, the flow amount of the refrigerant to each of the outdoor air heat exchanger 14 and the water-cooling heat exchanger 5 is adjusted on the basis of the water temperature detected by the water temperature sensor 23. Consequently, to set the preset water temperatures t2 and t3 at will enables the heat exchanger performance in the outdoor air heat exchanger 14 and the water-cooling heat exchanger 5 to be adjusted at will. In short, the heat pump water heater X1 is capable of adjusting at will the priority between the hot water supply amount and the energy consumption efficiency.
Moreover, when the water on the hot water supply circuit 2 may possibly freeze, the refrigerant flow into the water-cooling heat exchanger 5 is blocked, so that the freeze is prevented, and furthermore, damages in the water-cooling heat exchanger 5 as well as the components on the hot water supply circuit 2 are prevented.

Example 1

Here, Fig. 3 shows another variation of an expander 15, and Fig. 4 is a flow chart explaining another example of the adjusting process of the refrigerant flow.
In the above-mentioned embodiment, the expander 15 capable of controlling the flow and/or the flow amount of the refrigerant toward the water-cooling heat exchanger 5 is employed. In the present Example 1, as shown in Fig. 3, the configuration comprises, instead of the expander 15, a solenoid valve 15b for adjusting the flow of the refrigerant from the water-heating heat exchanger 3 to the water-cooling heat exchanger 5, as well as a capillary tube 15a for expanding the refrigerant flowing from the solenoid valve 15b to the water-cooling heat exchanger 5. In addition, the capillary tube 15a has a length and a tube inner diameter that are suitable for realizing the most appropriate flow amount of the refrigerant for the best efficiency.
Such configuration enables only the refrigerant flow (flowing/blocked) into the water-cooling heat exchanger 5 to be controlled, by controlling the open/close of the solenoid valve 15b with the controller.
In short, in a configuration where, instead of the expander 15, the capillary tube 15a and the solenoid valve 15b are comprised, the steps S1 to S4 in the adjusting process of the refrigerant flow described in the above embodiment (see the flow chart in Fig. 2) are executed as shown in the flow chart in Fig. 4.
Hence, when the water on the hot water supply circuit 2 may possibly freeze, the refrigerant flow into the water-cooling heat exchanger 5 is blocked, so that the freeze is prevented, and furthermore, damages in the water-cooling heat exchanger 5 as well as the components on the hot water supply circuit 2 are prevented.
A configuration according to Example 1, unlike the above-mentioned embodiment, does not conduct a detailed adjustment of the refrigerant flow amount, however, it performs an efficient heating of the mid-temperature hot water since being simple and inexpensive.

Example 2

In the above-mentioned embodiment, the distribution amount of the refrigerant to each of the refrigerant circuit 1a and the refrigerant circuit 1b in the refrigerant circuit 1, in short, the flow and/or the flow amount of the refrigerant toward the water-cooling heat exchanger 5 is adjusted so that the temperature of the water flowing into the water-heating heat exchanger 3 is adjusted.
In the present Example 2, another technique for adjusting the temperature of the water flowing into the water-heating heat exchanger 3 is explained. Here, Fig. 5 is a block diagram showing a general structure of a heat pump water heater X2 according to Example 2 of the present invention, and Fig. 6 is a flow chart explaining one example of the procedure for the adjusting process of the water flow amount which is conducted in a heat pump water heater X2. Additionally, with respect to the components and the process similar to those in the heat pump water heater X1 explained in the above-mentioned embodiment, the same symbols are allocated to same elements in Figs 5 and 6, so that a repetitive description thereof is omitted.
A heat pump water heater X2 according to Example 2 is different from the above-mentioned heat pump water heater X1 in that a distributor 25 (one example of the water distribution means) is provided in the hot water supply circuit 2, so that the water supplied from the lower layer in the storage tank 4 is distributed to each of a hot water supply circuit 2a (one example of the first water flow channel) and a hot water supply circuit 2b (one example of the second water flow channel).
The distributor 25 is controlled by the controller so that the distribution amount of the water by the distributor 25 can be adjusted. Here, the controller at the time of conducting the present adjusting process corresponds to the adjusting means for water distribution amount. In addition, the distributor 25 is one example of a water distribution means for distributing the water supplied from the storage tank 4, and may be configured by combining such as, for example, solenoid valves.
The hot water supply circuit 2a is a water flow channel in which the followings are sequentially connected: the lower layer in the storage tank 4, the water temperature sensor 21, the circulation pump 22, the distributor 25, the water-cooling heat exchanger 5, the water temperature sensor 23, the water-heating heat exchanger 3, the water temperature sensor 24, and the upper layer in the storage tank 4.
The hot water supply circuits 2b is also a water flow channel in which the followings are sequentially connected: the lower layer in the storage tank 4, the water temperature sensor 21, the circulation pump 22, the distributor 25, the water temperature sensor 23, the water-heating heat exchanger 3, the water temperature sensor 24, and the upper layer in the storage tank 4. In short, the hot water supply circuit 2b is a flow channel that bypasses the water-cooling heat exchanger 5.
The water discharged from the water-cooling heat exchanger 5 in the hot water supply circuit 2a and the water flowing as bypassing the water-cooling heat exchanger 5 in the hot water supply circuit 2b join together, before flowing into the water-heating heat exchanger 3.
In the heat pump water heater X2 according to the present Example 2, the default value of the water amount to be distributed to the hot water supply circuits 2a and 2b by the distributor 25 is previously set, however, the water amount to be distributed thereafter is changeable in the later-described adjusting process of the water flow amount (see the flow chart in Fig. 6).
In what follows, as referring to Fig. 5, one example of the procedure for adjusting process of the water flow amount to be executed by the controller in the heat pump water heater X2 is explained in accordance with the flow chart in Fig. 6. In addition, S1, S2 and so on in the figure are identification symbols representing the process steps.
Here, only the process steps different from those in the adjusting process of the refrigerant flow (see the flow chart in Fig. 2) described in the above-mentioned embodiment are explained. In the adjusting process of the water flow amount, instead of the steps S52 and S6 in the adjusting process of the refrigerant flow in the above-mentioned embodiment, a step S71 and a step S72 are respectively performed.
In the step S51, when the water temperature detected by the water temperature sensor 23 is judged as being lower than a preset water temperature t3 (one example of the sixth prescribed temperature), the process proceeds to the step S71 instead of the step 552.
In the step S71, to control the distributor 25 by the controller reduces the flow amount of the water toward the water-cooling heat exchanger 5 in the hot water supply circuit 2a by a prescribed value. This reduces the water amount cooled by the water-cooling heat exchanger 5, so that the temperature of the water joining from the hot water supply circuits 2a and 2b and flowing into the water-heating heat exchanger 3 is increased. Additionally, the water flow into the hot water supply circuit 2a may be blocked by the distributor 25 in this moment.
On the other hand, in the step S5, when the water temperature detected by the water temperature sensor 23 is judged as being equal to or higher than the preset water temperature t2 (one example of the fifth prescribed temperature), the process proceed to the step S72 instead of the step S6.
In the step S72, to control the distributor 25 by the controller reduces the flow amount of the water toward the water-cooling heat exchanger 5 in the hot water supply circuit 2a by a prescribed value. This increases the water amount cooled by the water-cooling heat exchanger 5, so that the temperature of the water joining from the hot water supply circuits 2a and 2b and flowing into the water-heating heat exchanger 3 can be decreased. Additionally, in this moment, the water flow into the hot water supply circuit 2b may be blocked by the distributor 25.
As described above, in the present adjusting process of the water flow amount, the distribution amount of the water to each of the hot water supply circuits 2a and 2b in the hot water supply circuit 2 is adjusted on the basis of the water temperature detected by the water temperature sensor 23, so that the temperature of the water flowing into the water-heating heat exchanger 3 can be properly adjusted. Here, the controller at the time of conducting the present adjusting process corresponds to the adjusting means for water distribution amount.
Additionally, in another example, the distribution amount of the water to each of the hot water supply circuits 2a and 2b in the hot water supply circuit 2 may be adjusted on the basis of the water temperature detected by the water temperature sensor 21. More specifically, on condition that the water temperature detected by the water temperature sensor 21 is equal to or higher than the preset water temperature (one example of the fourth prescribed temperature, around 35 degrees centigrade), the distributor 25 begins the water flow into the hot water supply circuit 2a, while on condition that it is below the preset water temperature, the distributor 25 may block the water flow into the hot water supply circuit 2a. Here, the controller at the time of conducting the present adjusting process also corresponds to the adjusting means for water distribution amount.
Additionally, in another example, the adjusting process of the refrigerant flow described in the above-mentioned embodiment (see the flow chart in Fig. 2), and the adjusting process of the water flow amount described in the present Example 2 (see the flow chart in Fig. 6) may be performed simultaneously. More specifically, each amount of the refrigerant and the water flowing into the water-cooling heat exchanger 5 may be adjusted base on the water temperatures detected by the water temperature sensors 21 and 23.

Example 3

In a configuration where the outdoor air heat exchanger 14 and the water-cooling heat exchanger 5 are connected in series, the flow and the flow amount of the refrigerant toward each of the outdoor air heat exchanger 14 and the water-cooling heat exchanger 5 may be controlled independently.
More specifically, there may be a configuration, in which a refrigerant channel flowing into the outdoor air heat exchanger 14 via the water-cooling heat exchanger 5, a bypassing channel flowing into the outdoor air heat exchanger 14 bypassing the water-cooling heat exchanger 5, and a distributor for distributing the refrigerant discharged from the water-heating heat exchanger 3 to each said channel are included. And also, the controller controls the amount of the refrigerant to be distributed by the distributor.
In such configuration, to adjust the amount of the refrigerant distributed by the distributor enables the amount of the refrigerant flowing into each of the refrigerant channel and the bypassing channel, in short, the flow and the flow amount of the refrigerant toward each of the outdoor air heat exchanger 14 and the water-cooling heat exchanger 5, to be adjusted independently.
Consequently, when the water flowing from the storage tank 4 may possibly freeze in the water-cooling heat exchanger 5, only the flow amount of the refrigerant toward the water-cooling heat exchanger 5 may be reduced or blocked.

Example 4

Here, Fig. 7 is a block diagram showing a general structure of a heat pump water heater X3 according to Example 4. Hereinafter, in reference to Fig. 7, the configuration of the heat pump water heater X3 according to Example 4 is explained. In addition, the components same as those in the heat pump water heater X2 described in Example 2 (see Fig. 5) are allocated with the same symbols, thereby omitting the description thereof.
The heat pump water heater X3 comprises, instead of the refrigerant circuit 1 (see Fig. 5), a refrigerant circuit 100 for circulating the refrigerant. Sequentially connected in the refrigerant circuit 100 arc the compressor 11, the water-heating heat exchanger 3, a throttle mechanism 101 (an expander), the outdoor air heat exchanger 14, and the water-cooling heat exchanger 5.
In the hot water supply circuit 2a, the water flows from the lower part in the storage tank 4, via the circulation pump 22 and the distributor 25, and through the water-cooling heat exchanger 5, then into the water-heating heat exchanger 3. In the hot water supply circuit 2b, the water flows from the lower part in the storage tank 4, via the circulation pump 22 and the distributor 25 (corresponding to a switching valve), then into the water-heating heat exchanger 3.
The performance of the thus configured heat pump water heater X3 is explained hereinafter.
In the refrigerant circuit 100, the refrigerant at high temperature and high pressure discharged from the compressor 11 flows in the direction shown with a solid arrow, and gives the water heat in the water-heating heat exchanger 3. After that, the throttle mechanism 101 reduces the pressure of the refrigerant to decrease its temperature, After that, the refrigerant at low temperatures absorbs heat from the air in the outdoor air heat exchanger 14, and returns to the compressor 11 via the water-cooling heat exchanger 5. In the water-cooling heat exchanger 5, when the water is flowing in the hot water supply circuit 2a, the refrigerant in the refrigerant circuit 100 absorbs heat also from the water.
In this moment, when the temperature of the water stored in the lower part in the storage tank 4 is almost the same as the one of the water supplied from the water supply port, in other words, when the detected temperature of the water temperature sensor 21 is lower than the preset temperature (for example, 35 degrees centigrade), the water to flow out of the lower part in the storage tank 4 by means of the circulation pump 22 is allowed to flow to the side of the hot water supply circuit 2b by the distributor 25, and increases its temperature by absorbing heat from the refrigerant as passing through the water-heating heat exchanger 3. After that, the water flows into the upper part in the storage tank 4 to be stored therein, and thus, the water at high temperature is stored in the storage tank 4. Here, additionally, the heat pump water heater X3 is controlled by adjusting the circulating water amount of the circulation pump 22 so that the water temperature sensor 24 indicates a preset hot water temperature. And moreover, the heat pump water heater X3 is controlled by adjusting the rotation number of the compressor 11 so that the heating performance achieves a prescribed level.
In the load side, when the hot water supply cock 43 is opened, the water at high temperature flows out to the hot water supply port from the upper part in the storage tank 4, by being pushed by the water flowing from the water supply port into the lower part in the storage tank 4 by the water pressure.
And also, for the purpose of using the water in the storage tank 4 for heating, the water at high temperature flowing out from the upper part in the storage tank 4 using the water circulation pump 61 flows in the direction shown with a solid arrow, and gives heat to the heating brine flowing in the heat exchanger for heating 62, before flowing into the lower part in the storage tank 4. On the other hand, the heating brine is circulated in the direction shown with a solid arrow by means of the brine circulation pump 64, and then releases the heat, that has been given at the heat exchanger for heating 62, in the heater 64 toward the indoor to perform heating. In this moment, the temperature of the water, that has given heat to the heating brine in the heat exchanger for heating 62 and then flowing into the lower part in the storage tank 4, is lower than the temperature of the supplying hot water by 10 to 20 degrees centigrade, however, is slightly higher than the water supplied from the water supply port, i.e., for example, around 45 degrees centigrade.
As mentioned above, when the temperature detected by the water temperature sensor 21 is above the preset temperature (for example, 35 degrees centigrade), the use of the water in the storage tank 4 for heating causes the water flowing out from the lower part in the storage tank 4 using the circulation pump 22 to flow to the side of the hot water supply circuit 2a. by the distributor 25, and thereby giving heat to the refrigerant in the water-cooling heat exchanger 5 to reduce its temperature. And then, the water at the reduced temperature absorbs heat from the refrigerant while passing through the water-heating heat exchanger 3, before flowing into the upper part in the storage tank 4 to be stored therein. Consequently, hot water at high temperature is stored in the storage tank 4. Here again, additionally, the heat pump water heater X3 is controlled by adjusting the circulating water amount of the circulation pump 22 so that the water temperature sensor 24 indicates a preset hot water temperature.
And moreover, the heat pump water heater X3 is controlled by adjusting the rotation number of the compressor 11 so that the heating performance achieves a prescribed level.

Example 5

Next, a heat pump water heater X4 according to Example 5 in the present invention is explained. The configuration of the heat pump water heater X4 is the same as the heat pump water heater X3 (see Fig. 7) described in Example 4. Hereinafter, the performance of the heat pump water heater X4 in Example 5 is explained.
According to the heat pump water heater X4 in the present Example 5, when the water temperature detected by the water temperature sensor 23 is lower than a preset temperature, the distributor 25 is controlled so that the flow amount toward the hot water supply circuit 2b is greater, and on the other hand, when the detected temperature is higher than the preset temperature, the distributor 25 is controlled so that the flow amount toward the hot water supply circuit 2a is greater. Here again, additionally, the heat pump water heater X4 is controlled by adjusting the circulating water amount of the circulation pump 22 so that the water temperature sensor 24 indicates a preset hot water temperature. And moreover, the heat pump water heater X4 is controlled by adjusting the rotation number of the compressor 11 so that the heating performance achieves a prescribed level,
The heat pump water heater X4 is capable of operating a heat pump cycle by conducting such as the heating operation even when the temperature of the water to be heated and stored in the lower part in the storage tank 4 is high, and moreover, capable of improving COP by reducing the discharge pressure of the heat pump cycle. In addition, the present invention is not limited for the use where a heater 64 is disposed in the load side, and may be applied to various devices using stored hot water, such as a bath reheating device: a device that does not necessarily supply water, in other words, that does not consume hot water by supplying to the outside.
It should be understood that the embodiment as well as Examples 1 to 5 disclosed in the above are mere examples in all views, thereby intending no limitation on the scope of the invention. The scope of the present invention is specified in the Claims and not limited to the above-mentioned embodiment as well as Examples 1 to 5. Any variations and modifications which would be obvious to one skilled in the art are intended to be included within the scope of the present invention.

Claims

A heat pump water heater comprising:
a refrigerant circulation channel in which a refrigerant is circulated, a water flow channel in which water flows, a first water heat exchanger for conducting the heat exchange in the refrigerant circulation channel between the refrigerant discharged from

a compressor and the water flowing in the water flow channel, a storage tank for storing water discharged from the first water heat exchanger, an expander for expanding the refrigerant discharged from the first water heat exchanger, an outdoor air heat exchanger for conducting heat exchange between the refrigerant flowing from

the expander toward the compressor and outdoor air, and a second water heat exchanger for conducting heat exchange between the refrigerant flowing from the expander toward the compressor and the water supplied from the storage tank,
wherein a refrigerant temperature detection means for detecting the temperature of the refrigerant discharged from the expander, and
an adjusting means of the refrigerant flow for adjusting the flow and/or the flow amount of the refrigerant toward the second water heat exchanger on the basis of the refrigerant temperature detected by the refrigerant temperature detection means are included.
A heat pump water heater according to Claim 1, further comprising a heating cycle which uses hot water stored in the storage tank as a heating medium.
A heat pump water heater according to any one of Claims 1 and 2, wherein the adjusting means of the refrigerant flow blocks the flow of the refrigerant toward the second water heat exchanger when the temperature detected by the refrigerant temperature detection means is the one at which the water freezes by the heat exchange with the refrigerant.
A heat pump water heater according to any one of Claims 1 to 3;
wherein the expander comprises a first expander for discharging the refrigerant toward the outdoor air heat exchanger and a second expander for discharging the refrigerant toward the second water heat exchanger, and
the refrigerant temperature detection means detects the temperatures of the refrigerant discharged from the first expander and/or from the second expander.
A heat pump water heater according to Claim 4,
wherein the second expander comprises a solenoid valve for adjusting the flow of the refrigerant from the first water heat exchanger toward the second water heat exchanger, and a capillary tube for expanding the refrigerant flowing from the solenoid valve toward the second water heat exchanger; and
the adjusting means of the refrigerant flow adjusts the flow or the refrigerant flowing from the first water heat exchanger toward the second water heat exchanger by controlling the solenoid valve.
A heat pump water heater according to any one of Claims 1 to 5, further comprising a first water temperature detection means for detecting the temperature of the water discharged from the storage tank,
wherein the adjusting means of the refrigerant flow adjusts the flow and/or the flow amount of the refrigerant toward the second water heat exchanger on the basis of the water temperature detected by the first water temperature detection means.
A heat pump water heater according to Claim 6, wherein the adjusting means of the refrigerant flow allows the refrigerant to flow into the second water heat exchanger on condition that the water temperature detected by the first water temperature detection means is higher than or equal to a first prescribed temperature, while on the other hand, said adjusting means of the refrigerant flow blocks the flow of the refrigerant into the second water heat exchanger on condition that the water temperature detected by the first water temperature detection means is lower than the first prescribed temperature.
A heat pump water heater according to any one of Claims 1 to 7, further comprising a second water temperature detection means for detecting the temperature of the water flowing into the first water heat exchanger,
wherein the adjusting means of the refrigerant flow adjusts the flow and/or the flow amount of the refrigerant into the second water heat exchanger on the basis of the water temperature detected by the second water temperature detection means.
A heat pump water heater according to Claim 8, wherein the adjusting means of the refrigerant flow increases the flow amount of the refrigerant into the second water heat exchanger on condition that the water temperature detected by the second water temperature detection means is higher than or equal to a second prescribed temperature, while on the other hand, said adjusting means of the refrigerant flow decreases the flow amount of the refrigerant into the second water heat exchanger on condition that the water temperature detected by the second water temperature detection means is equal to or lower than a third prescribed temperature that is lower than the second prescribed temperature.
A heat pump water heater according to any one of Claims 8 and 9, wherein the water flow channel comprises a first water flow channel connected from the storage tank through the first water heat exchanger and back to the storage tank, and a second water flow channel connected sequentially from the storage tank through the second water heat exchanger, the first water heat exchanger, and back to the storage tank, and said heat pump water heater further comprises: a water distribution means for distributing the water supplied form the storage tank to the first water flow channel and the second water flow channel, and an adjusting means for water distribution amount for adjusting the amount of the water distributed by the water distribution means on the basis of the water temperature detected by the first water temperature detection means and/or the second water temperature detection means.
A heat pump water heater according to Claim 10, wherein the adjusting means for water distribution amount instructs the water distribution means to distribute the water to the second water flow channel on condition that the water temperature detected by the first water temperature detection means is equal to or higher than a fourth prescribed temperature.
A heat pump water heater according to any one of Claims 10 and 11, wherein the adjusting means for water distribution amount increases the distribution amount of the water to the second water flow channel using the water distribution means on condition that the water temperature detected by the second water temperature detection means is equal to or higher than a fifth prescribed temperature, while on the other hand, said adjusting means for water distribution amount decreases the distribution amount of the water to the second water flow channel using the water distribution means on condition that the water temperature detected by the second water temperature detection means is equal to or lower than a sixth prescribed temperature that is lower than the fifth prescribed temperature.
A heat pump water heater comprising a water flow channel for flowing water and a refrigerant circulation channel for circulating a refrigerant,
wherein the refrigerant circulation channel sequentially connects: a compressor, a first water heat exchanger for providing heat with the water in the water flow channel from the refrigerant in the refrigerant circulation channel, a throttle mechanism, an outdoor air heat exchanger for providing heat with the refrigerant in the refrigerant circulation channel from the external air, and a second water heat exchanger for providing heat with the refrigerant in the refrigerant circulation channel from the water in the water flow channel; and
the water flow channel sequentially connects: a storage tank, a circulation pump, the second water heat exchanger, and the first water heat exchanger.
A heat pump water heater comprising a water flow channel for flowing water and a refrigerant circulation channel for circulating a refrigerant,
wherein the refrigerant circulation channel sequentially connects: a compressor, a first water heat exchanger for providing the water in the water flow channel with heat from
a refrigerant in the refrigerant circulation channel, a throttle mechanism, an outdoor air heat exchanger for providing the refrigerant in the refrigerant circulation channel with heat from the external air, and a second water heat exchanger for providing the refrigerant in the refrigerant circulation channel with heat from the water in the water flow channel, and
the water flow channel includes a first water flow channel and a second water flow channel, and
the first water flow channel sequentially connects: a storage tank, a circulation pump, a switching valve for switching the water flow between the first water flow channel and the second water flow channel, and the first water heat exchanger, and the second water flow channel sequentially connects: a storage tank, a circulation pump, the switching valve, the second water heat exchanger, and the first water heat exchanger.
A heat pump water heater according to Claim 14, comprising first water temperature detection means for detecting the temperature of the water flowing out from the storage tank,
wherein when the water temperature detected by the first water temperature detection means is higher than a preset temperature, the water flow channel is switched to the second water flow channel by the switching valve.
A heat pump water heater according to Claim 14, comprising:
a first water temperature detection means for detecting the temperature of the water flowing out from the storage tank, and

a second water temperature detection means for detecting the temperature of the water flowing into the first water heat exchanger,
wherein when the water temperature detected by the first water temperature detection means is higher than a preset temperature, at least a part of the water flow channel is switched to the second water flow channel by the switching valve, and
when the water temperature detected by the second water temperature detection means is lower than a preset temperature, the switching valve is controlled so that the flow amount into the first water flow channel is greater, and on the other hand,
when the water temperature detected by the second water temperature detection means is higher than a preset temperature, the switching valve is controlled so that the flow amount into the second water flow channel is greater.