JP2002340440A - Heat pump hot-water supplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water storage type heat pump hot-water supplier that is improved in operational efficiency and is contrived to effectively utilize the hot-water capacity of a hot-water storage tank. SOLUTION: This heat pump hot-water supplier is provided with a flow rate control means 10 which controls a flow regulating valve 11 for fixing a boiling temperature which is the temperature of water at the water-side outlet of a refrigerant-water heat exchanger 2, a detecting means 13 which detects the completion of the boiling of all hot water stored in the hot-water storage tank 5 just before the completion, and a control means 12 which changes the valve travel of the valve of a pressure reducing device 3 when the signal from the detecting means 13 becomes a prescribed one. Since the valve travel of the valve of the pressure reducing device 3 is changed when the boiling of the hot water is near completion and the discharge pressure of a compressor 1 rises, this hot-water supplier can be operated for heating hot water to a high feed water temperature. Consequently, the supplier can effectively utilize the hot-water capacity of the tank 5 and, in addition, can be operated highly efficiently for heating hot water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply type heat pump water heater.

[0002]

2. Description of the Related Art A conventional heat pump water heater of this kind is disclosed in Japanese Patent Application Laid-Open No. 60-164157. FIG. 22 is a configuration diagram of a conventional heat pump water heater. In FIG. 22, a compressor 1, a refrigerant-to-water heat exchanger 2,
A refrigerant circulation circuit including a decompression device 3 and an evaporator 4 and a hot water supply circuit connecting a hot water storage tank 5, a circulation pump 6, the refrigerant-to-water heat exchanger 2, and an auxiliary heater 7 are discharged from the compressor 1. The high-temperature, high-pressure superheated gas refrigerant flows into the refrigerant-to-water heat exchanger 2, where it heats the water sent from the circulation pump 6. Then, the condensed and liquefied refrigerant is decompressed by the decompression device 3 and flows into the evaporator 4 where it absorbs atmospheric heat to evaporate and return to the compressor 1. On the other hand, the hot water heated by the refrigerant / water heat exchanger 2 flows into the upper portion of the hot water storage tank 5 and is gradually stored from above. Then, when the inlet water temperature of the refrigerant-to-water heat exchanger 2 reaches a set value, the feedwater temperature detecting means 8 detects it, stops the heat pump operation by the compressor 1 and switches to the independent operation of the auxiliary heater 7. Things.

[0003]

However, in the above-described configuration of the prior art, as the boiling operation time elapses, a hot-water mixed layer is formed at a portion where hot water and water in the hot-water storage tank 5 come into contact with each other, and the layer is gradually formed. Expand. FIG. 23 shows a temperature distribution of hot water in hot water storage tank 5. In the figure, T1 is the boiling temperature (high-temperature hot water), and T2 is the city water temperature (low-temperature hot water). The above-mentioned hot-water mixture layer is generated by heat conduction and convection between the high-temperature hot water and the low-temperature hot water, and is transferred from the high-temperature hot water to the low-temperature hot water. To rise. Therefore, when the boiling of the hot water storage tank 5 is nearly completed, the temperature of the feedwater flowing into the refrigerant-to-water heat exchanger 2 increases, so that the discharge pressure of the compressor 1 increases and the winding temperature of the motor increases. For example, durability of the compressor 1 becomes an issue.

In FIG. 24, the horizontal axis indicates the feed water temperature flowing into the refrigerant-to-water heat exchanger 2, and the vertical axis indicates the discharge pressure of the compressor 1 at that time. It is a graph showing the relationship. The pressure P in the figure is a normal upper limit pressure, and in order to guarantee the durability of the compressor 1,
In normal operation, it is necessary to operate at or below this pressure. The supply water temperature at the time of the pressure P is T3 from the figure. Further, the lower limit of the effective hot water temperature is Tu (for example, 45 ° C.), and the above-mentioned T3
And Tu are shown in FIG. In the cross-sectional view of the hot water storage tank 5 shown on the left side of the figure, a region below the hot water temperature T3 is a region that can be boiled, and a region above Tu is a region that can be used as effective hot water. However, the area between the hot water temperatures T3 and Tu (shaded area) is an area that cannot be used as effective hot water.

As described above, in the conventional configuration, the operation must be stopped in a state where the water temperature flowing through the refrigerant-to-water heat exchanger 2 is low, so that the lower part of the hot water storage tank 5 is in a state of low-temperature water. As a result, the hot water capacity of the hot water storage tank 5 cannot be used effectively. Therefore, the amount of hot water stored decreases, and the hot water supply load cannot be satisfied. As one method for solving this, it is conceivable to increase the capacity of the hot water storage tank 5. However, in this case, there is a problem that the installation area of the hot water tank 5 is increased, the degree of freedom of installation is limited, and the cost is increased. Further, as another method, there is a method of increasing the amount of stored hot water by operating the auxiliary heater 7 alone after stopping the heat pump operation. But in this case,
Since heating is performed by a heater or the like, there is a problem that power consumption is increased and efficiency is deteriorated.

The present invention solves the above-mentioned conventional problems, and stores high-temperature hot water up to the lower portion of a hot water storage tank with low power consumption without an abnormal rise in temperature and abnormal pressure of a compressor.
It is an object of the present invention to provide a heat pump water heater capable of effectively utilizing a hot water capacity.

[0007]

In order to solve the above-mentioned conventional problems, a heat pump water heater according to the present invention has a means for detecting immediately before the completion of boiling of the entire hot water storage tank, and a means for immediately before the completion of boiling. And control means for controlling so as to open the valve opening of the pressure reducing device when it is detected. Therefore, when the discharge pressure of the compressor nears the completion of boiling and the discharge pressure of the compressor rises, the valve opening of the pressure reducing device is controlled to open, and the discharge pressure is kept low, so that hot water supply heating operation can be performed up to a high supply water temperature. It becomes.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a refrigerant circulation circuit in which a compressor, a refrigerant-to-water heat exchanger, a decompression device, and an evaporator are sequentially connected, a hot water tank, a circulation pump, and the refrigerant-to-water. A hot water supply circuit to which a heat exchanger is sequentially connected; a heating completion detecting means for detecting immediately before the whole hot water tank is heated; and a pressure reducing device when a signal from the heating completion detecting means becomes a predetermined signal. Control means for changing the valve opening of the compressor, when the boiling is approaching completion and the discharge pressure of the compressor rises, the valve opening of the pressure reducing device is controlled to be opened, and the discharge pressure is lowered. The hot water supply heating operation can be performed up to the holding water temperature and the high supply water temperature, and the hot water capacity of the hot water storage tank can be effectively used.

According to a second aspect of the present invention, there is provided a control device for determining the change width of the valve opening of the pressure reducing device in accordance with the outside air temperature obtained from the outside air temperature detecting means for detecting the outside air temperature. Since the valve opening of the decompression device is changed optimally according to the temperature, the hot water capacity of the hot water tank can be used effectively, and
An efficient hot water supply heating operation can be performed.

According to a third aspect of the present invention, an optimal pressure reducing device according to the water supply temperature is provided by providing control means for changing a valve opening of the pressure reducing device for each of a plurality of predetermined water temperatures. Since the valve opening degree is changed, the wasteful area that cannot be used as effective hot water is reduced, so that the hot water capacity of the hot water storage tank can be effectively used, and an efficient hot water supply heating operation can be performed.

According to a fourth aspect of the present invention, there is provided a control means for increasing the amount of change in the valve opening of the pressure reducing device as the temperature of the water supply increases, so that the pressure reducing device is operated at a high temperature of the water supply where the rise in discharge pressure is large. Since the discharge pressure is greatly reduced by increasing the amount of change in the valve opening and the valve opening of the decompression device is optimally changed according to the supply water temperature, the hot water capacity of the hot water storage tank can be used effectively and the efficiency can be improved. A good hot water supply heating operation is possible.

According to a fifth aspect of the present invention, the control means for changing the valve opening of the pressure reducing device at predetermined time intervals is provided, so that the valve opening of the pressure reducing device is optimized just before the completion of boiling. Since the degree is changed, the hot water capacity of the hot water storage tank can be effectively used, and an efficient hot water supply heating operation can be performed.

According to a sixth aspect of the present invention, there is provided control means for shortening the time interval for changing the valve opening of the pressure reducing device as the boiling is completed, so that the discharge pressure is reduced as the boiling is completed. When the rise is large, the change in the valve opening of the decompression device is increased to greatly reduce the discharge pressure, and the optimum valve opening of the decompression device is changed, so that the hot water capacity of the hot water storage tank can be used effectively, and An efficient hot water supply heating operation can be performed.

According to a seventh aspect of the present invention, as the detecting means immediately before the completion of the boiling, the time measuring means for measuring the time of the maximum flow rate when the flow rate passing through the flow regulating valve reaches the maximum flow rate is provided. As a result, it is detected that the boiling flow rate has reached a maximum for a predetermined time, the valve opening of the pressure reducing device is changed, the discharge pressure is kept low, and the heating operation is continued. The hot water supply heating operation can be performed up to the temperature, and the hot water capacity of the hot water storage tank can be used effectively.

The invention according to claim 8 uses a discharge pressure detecting means as a means for detecting immediately before the completion of boiling, and a control means for controlling the valve opening of the pressure reducing device to be opened when the set reference pressure is reached. With this arrangement, the hot water capacity of the hot water storage tank can be effectively used, and the pressure is directly controlled, so that the durability of the compressor can be more reliably improved.

According to a ninth aspect of the present invention, a hot water tank temperature detecting means for detecting a lower temperature of the hot water tank is used as a means for detecting immediately before completion of boiling, and when a predetermined hot water tank temperature is reached, the valve opening of the pressure reducing device is increased. By providing a control means to control the opening, the hot water capacity of the hot water tank can be used effectively, and the temperature of the hot water tank is directly detected and controlled. It becomes.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram of a heat pump water heater according to Embodiment 1 of the present invention, and FIG. 2 is an operating state of a compressor with respect to an operation time of the heat pump water heater, a valve opening degree and discharge of a pressure reducing device. FIG. 3 is a graph showing pressure and water supply temperature, and FIG. 3 is an explanatory diagram showing a temperature distribution of a hot water tank of the heat pump water heater. Note that the same reference numerals are used for the same components as those in FIG.

In FIG. 1, a flow rate control means 10 controls an opening degree of a flow rate control valve 11 by a signal from a boiling temperature detection means 9 provided at a water side outlet of the refrigerant-to-water heat exchanger 2.
The outlet water temperature (boiling temperature) of the refrigerant-to-water heat exchanger 2 is raised to be substantially constant. Further, the control means 12
The opening degree of the pressure reducing device 3 is controlled by a signal from the detection unit 13 immediately before the completion of the boiling, which detects immediately before the completion of the boiling. Examples of the flow control valve 11 include an electric valve driven by a stepping motor.

As the means 13 for detecting immediately before the completion of boiling, for example, a feedwater temperature detecting means 8 for detecting a feedwater temperature which is a water-side inlet water temperature of the refrigerant-to-water heat exchanger 2 is used. The pressure reducing device 3 includes an electric expansion valve (not shown) and the like.

Next, the operation and operation will be described. In FIG. 2, the horizontal axis indicates the operating time, and the vertical axis indicates the operating state of the compressor, the valve opening degree of the pressure reducing device, the discharge pressure, and the feedwater temperature. It shows the relationship between the opening degree, the discharge pressure, and the feedwater temperature. As described in the conventional example, when the boiling of the hot water storage tank 5 is nearly completed, the temperature of the supply water flowing into the refrigerant-to-water heat exchanger 2 increases. That is, when the water flowing into the refrigerant-to-water heat exchanger 2 becomes the portion of the hot water mixture layer described above, as shown in FIG. When the feed water temperature detecting means 8 as the detecting means 13 immediately before the completion of the boiling detects the detected temperature Th immediately before the completion of the boiling (which is lower than the boiling temperature T1), the control means 12 sets the valve of the pressure reducing device 3 to Increase the opening (open). At this time, the discharge pressure decreases from P1 to P2. Thereafter, as the operation time elapses, the feedwater temperature further rises, and the discharge pressure rises accordingly. Then, when the feedwater temperature detecting means 8 detects the feedwater temperature T3a at which the normal upper limit pressure P is reached, the compressor is stopped and the heating operation is ended. The thick dotted line in FIG.
This is a case of a conventional example in which the valve opening of the pressure reducing device 3 is not controlled. It can be seen that the water supply temperature at the operation limit increases from T3 to T3a, and the operation range increases.

FIG. 3 shows the temperature distribution of the hot water in the hot water storage tank 5.
In the sectional view of the hot water storage tank 5 shown on the left side of FIG.
The region below a is a region that can be boiled, and the region above Tu is a region that can be used as effective hot water. The area that cannot be used as effective hot water is the area between the hot water temperatures T3 and Tu in the case of the conventional example shown in FIG. 23, but the area between the hot water temperatures T3a and Tu (the hatched area) in the present embodiment. Part). In other words, the area between the hot water temperatures T3 and T3a (the shaded area indicated by the dotted line) is the hot water area that has become effective according to the present embodiment.

As described above, in this embodiment, the refrigerant circulation circuit in which the compressor, the refrigerant-to-water heat exchanger, the pressure reducing device, and the evaporator are sequentially connected, the hot water tank, the circulation pump, and the refrigerant-to-water heat exchange A hot water supply circuit to which water heaters are sequentially connected, a means for detecting immediately before the boiling of the entire hot water storage tank is completed, and a valve for the pressure reducing device when the signal from the means for immediately before the boiling becomes a predetermined signal. Control means for controlling the opening degree, by controlling the opening degree of the valve of the pressure reducing device when the boiling pressure is close to completion and the discharge pressure of the compressor increases, thereby controlling the discharge pressure. It is possible to perform the hot water supply heating operation up to a high supply water temperature by holding the supply water low, so that the hot water capacity of the hot water storage tank can be effectively used.

In this embodiment, the circulation pump 6 is provided between the water-side inlet of the refrigerant-to-water heat exchanger 2 and the hot water storage tank 5, and the flow control valve 11 is provided with the circulation pump 6 and the refrigerant-to-water heat exchanger. 2 is provided between the inlet of the circulating pump 6 and the hot water storage tank 5, but the position of the flow control valve 11 may be provided between the water-side outlet of the refrigerant and the water heat exchanger 2. The same operation and effect as those in the embodiment of FIG.

The refrigeration cycle may be a normal heat pump cycle in which the refrigerant-to-water heat exchanger 2 is used as a condenser and the discharge pressure is lower than the critical point, as described in the conventional example of FIG. However, a supercritical heat pump cycle in which the refrigerant-to-water heat exchanger 2 is used as a gas cooler and the discharge pressure is higher than the critical point may be used.

(Embodiment 2) FIG. 4 is a block diagram of a heat pump water heater according to Embodiment 2 of the present invention, and FIG. 5 is a graph showing discharge pressure with respect to valve opening degree of a pressure reducing device of the heat pump water heater.
FIG. 6 is a graph showing the change amount of the valve opening of the pressure reducing device with respect to the outside air temperature of the heat pump water heater and the detected temperature immediately before the completion of boiling.

The present embodiment is different from the first embodiment in that an outside air temperature detecting means 14 for detecting an outside air temperature and a first storage which stores a change amount of the valve opening of the pressure reducing device 3 with respect to the outside air temperature. And means 15 are provided. Note that the portions denoted by the same reference numerals as those in the first embodiment have the same configuration, and description thereof will be omitted.

Next, the operation and operation will be described. In FIG. 5, the horizontal axis indicates the valve opening of the pressure reducing device 3, the outside air temperature is set as a parameter (for example, 5 ° C. in winter, 18 ° C. in the middle period, 29 ° C. in summer, for example), and the discharge pressure is plotted on the vertical axis. 7 shows the relationship between the valve opening of the pressure reducing device 3 and the discharge pressure at a certain feedwater temperature. As shown in FIG.
When the valve opening degree becomes large, the discharge pressure decreases. Therefore, if the amount of change in the valve opening of the pressure reducing device 3 for reducing the discharge pressure from P1 to P2 is obtained, ΔS1 in winter (for example, 5 ° C.), ΔS2 in the intermediate period (for example, 18 ° C.), and summer ( At 29 ° C., for example, ΔS3 is obtained.

FIG. 6 shows the outside air temperature on the horizontal axis, and the change amount of the valve opening of the pressure reducing device 3 and the detected temperature immediately before the completion of boiling on the vertical axis, and shows the valve opening of the pressure reducing device 3 with respect to the outside air temperature. 9 shows the relationship between the change amount and the detected temperature immediately before the completion of boiling. The relationship between the outside air temperature and the amount of change in the valve opening of the pressure reducing device 3 is determined by the outside air temperature (5 ° C. in winter, 1
The change amount (△ S1 in winter, △ S2 in the interim period, △ S3 in summer) relative to 8 ° C. and 29 ° C. in summer. The relationship between the outside air temperature and the detected temperature immediately before the completion of boiling is as follows: at each outside air temperature (for example, 5 ° C. in winter, 18 ° C. in the intermediate period, and 29 ° C. in summer, for example), the feedwater temperature (boiling up) at which the discharge pressure is P1 It can be determined by obtaining the detected temperature immediately before completion Th). FIG. 6 shows these relationships, and the relationships in FIG. 6 are stored in the first storage unit 15.

The control means 12 periodically detects the supply water temperature from the supply water temperature detection means 8, which is the detection means 13 immediately before the completion of boiling, and further detects the outside air temperature from the outside air temperature detection means 14. Then, the amount of change of the valve opening of the pressure reducing device 3 with respect to the outside air temperature and the detected temperature Th immediately before the completion of boiling, which are stored in the first storage means 15, are obtained. And
If the feedwater temperature obtained from the feedwater temperature detecting means 8 is lower than the detected temperature Th immediately before the completion of boiling, the valve opening of the pressure reducing device 3 is not changed. Conversely, if the feedwater temperature is higher than the detected temperature Th immediately before the completion of boiling. The valve opening of the pressure reducing device 3 is changed (opened) by the change amount of the valve opening of the pressure reducing device 3 obtained from the first storage means 15. When the valve opening of the pressure reducing device 3 is changed, the discharge pressure decreases from P1 to P2. Thereafter, as described in the first embodiment, the feedwater temperature further increases with the elapse of the operation time, and the discharge pressure increases accordingly. Then, the feedwater temperature detecting means 8 detects that the feedwater temperature T3a becomes the normal upper limit pressure P.
Is detected, the compressor is stopped and the heating operation is terminated.

As described above, in the present embodiment, the control means for determining the amount of change in the valve opening of the pressure reducing device in accordance with the outside air temperature obtained from the outside air temperature detecting means for detecting the outside air temperature is provided. Since the valve opening of the decompression device is optimally changed in accordance with the outside air temperature, the hot water capacity of the hot water tank can be effectively used, and the efficient hot water supply heating operation can be performed.

(Embodiment 3) FIG. 7 is a block diagram of a heat pump water heater according to Embodiment 3 of the present invention, and FIG. 8 is a diagram showing a water supply temperature, a discharge pressure, a valve opening degree and a compression of a pressure reducing device with respect to an operation time of the heat pump water heater. It is a graph which shows the driving | running state of a machine.

This embodiment is different from the first embodiment in that a water supply temperature storage means 16 is provided. Note that the portions denoted by the same reference numerals as those in the first embodiment have the same configuration, and description thereof will be omitted.

Next, the operation and operation will be described. FIG. 8 shows the operation time on the horizontal axis, the feed water temperature, discharge pressure, the valve opening degree of the pressure reducing device, and the operating state of the compressor on the vertical axis. 4 shows a relationship between the opening degree and the operating state of the compressor. Th1 and Th2 (Th1 <Th2) shown in the figure are detected temperatures Th immediately before the completion of boiling, and are a detected temperature immediately before the completion of the first boiling and a detected temperature immediately before the completion of the second boiling, respectively.
The first detected temperature Th1 immediately before the completion of boiling and the second detected temperature Th2 immediately before the completion of boiling are stored in the water supply temperature storage means 1.
6 is stored.

As described above, when the boiling of the hot water storage tank 5 is nearly completed, the temperature of the supply water flowing into the refrigerant-to-water heat exchanger 2 increases. The control means 12 periodically detects the feed water temperature from the feed water temperature detection means 8 which is the detection means 13 immediately before the completion of the boiling, and further detects the temperature immediately before the completion of the first boiling stored in the feed water temperature storage means 16. The temperature Th1 is obtained. And if the feed water temperature obtained from the feed water temperature detecting means 8 is lower than the detected temperature Th1 immediately before the completion of the first boiling,
The valve opening of the pressure reducing device 3 is not changed. Conversely, if the feedwater temperature is higher than the first detected temperature Th1 just before the completion of boiling, the valve opening of the pressure reducing device 3 is changed (opened). When the valve opening of the pressure reducing device 3 is changed, the discharge pressure decreases. After that, the control means 12 periodically detects the feed water temperature from the feed water temperature detecting means 8 which is the detecting means 13 immediately before the completion of boiling, and further,
The second detected temperature Th2 immediately before completion of the boiling stored in the water supply temperature storage means 16 is obtained. If the feed water temperature obtained from the feed water temperature detecting means 8 is lower than the second detected temperature immediately before the completion of boiling, the valve opening of the pressure reducing device 3 is not changed. If it is higher than the detection temperature Th2 just before completion, the valve opening of the pressure reducing device 3 is changed (opened). Similarly, when the valve opening of the pressure reducing device 3 is changed,
The discharge pressure decreases. Thereafter, as described in the first embodiment, the feedwater temperature further increases with the elapse of the operation time, and the discharge pressure increases accordingly. Then, when the feedwater temperature detecting means 8 detects the feedwater temperature T3a at which the normal upper limit pressure P is reached, the compressor is stopped and the heating operation is ended.

As described above, in the present embodiment, the control means for changing the valve opening of the pressure reducing device for each of a plurality of predetermined supply water temperatures is provided, so that the optimum value corresponding to the supply water temperature is provided. Since the valve opening of the decompression device is changed, there is less wasteful area that cannot be used as effective hot water, so that the hot water capacity of the hot water storage tank can be used effectively, and an efficient hot water supply heating operation can be performed. is there.

In this embodiment, two feed water temperatures are set as the detected temperature Th immediately before the completion of boiling. However, even if three or more feed water temperatures are set, the same operation and effect as those of the present embodiment can be obtained. Can be

(Embodiment 4) FIG. 9 is a block diagram of a heat pump water heater according to a fourth embodiment of the present invention, and FIG. 10 is a graph showing a discharge pressure and a valve opening of a pressure reducing device with respect to a water supply temperature of the heat pump water heater. 11 is a graph showing the amount of change in the valve opening of the pressure reducing device with respect to the feed water temperature of the heat pump water heater.

The present embodiment is different from the third embodiment in that a second storage means 17 for storing the amount of change of the valve opening of the pressure reducing device with respect to the feed water temperature is provided. Note that the portions denoted by the same reference numerals as in the third embodiment have the same configuration, and description thereof will be omitted.

Next, the operation and operation will be described. FIG.
Shows the relationship between the discharge pressure and the valve opening of the pressure reducing device with respect to the water supply temperature by taking the feed water temperature on the horizontal axis and the discharge pressure and the valve opening of the pressure reducing device on the vertical axis. In the figure, the dotted line indicates a case where the valve opening of the pressure reducing device 3 is constant. As can be seen from the figure, the higher the feedwater temperature, the more rapidly the discharge pressure increases. Further, T shown in FIG.
h1, Th2, Th3, Th4, Th5 (Th1 <Th
2 <Th3 <Th4 <Th5) is the feedwater temperature indicating the detected temperature Th immediately before the completion of the boiling, and is the first, second, third, fourth, and fifth detected temperatures immediately before the completion of the boiling, respectively. The first to fifth detected temperatures immediately before the completion of boiling are stored in the feedwater temperature storage means 16. Then, the feed water temperature detected from the feed water temperature detecting means 8 which is the detecting means 13 immediately before the completion of the boiling is stored in the feed water temperature storing means 16 and the detected temperature Th immediately before the completion of the boiling Th (Th1, Th2, Th3,
Th4, Th5) or more, the valve opening of the pressure reducing device 3 is changed (（S1, △ S2, △ S3, △ S4, △ S, respectively).
5) Do (open). As shown in the figure, the change amount of the valve opening degree of the pressure reducing device 3 at this time is made larger when the detected temperature immediately before the completion of boiling is higher. That is, when the detected temperature immediately before the completion of boiling is Th1 <Th2 <Th3 <Th4 <Th5,
The change amount of the valve opening degree of the pressure reducing device 3 is set to △ S1 <△ S2 <△ S3
<△ S4 <△ S5. In this way, as shown by the solid line in FIG. FIG. 11 shows the feedwater temperature on the horizontal axis and the pressure reducing device 3 on the vertical axis.
The relationship between the amount of change in the valve opening of the pressure reducing device 3 and the supply water temperature is shown by taking the amount of change in the valve opening of the second embodiment, and this relationship is stored in the second storage means 17.

The control means 12 periodically detects the feed water temperature from the feed water temperature detecting means 8 which is the detecting means 13 immediately before the completion of boiling. Then, the detected temperature Th (Th1, Th1) immediately before the completion of the boiling stored in the water supply temperature storage means 16 is stored.
2, Th3, Th4, Th5). If the feed water temperature obtained from the feed water temperature detecting means 8 is lower than the detected temperature Th immediately before the completion of boiling, the valve opening of the pressure reducing device 3 is not changed.
If it is higher, the change amount of the valve opening of the pressure reducing device with respect to the feed water temperature stored in the second storage means 17 (each of ΔS
1, ΔS2, ΔS3, ΔS4, ΔS5)
Change the valve opening (open).

As described above, in the present embodiment, the control means for increasing the change amount of the valve opening of the pressure reducing device as the water supply temperature becomes higher is provided. Since the discharge pressure is greatly reduced by increasing the amount of change in the valve opening of the device, and the valve opening of the decompression device is optimally changed according to the supply water temperature, the hot water capacity of the hot water tank can be used effectively, and In addition, an efficient hot water supply heating operation can be performed.

In this embodiment, five feed water temperatures are set as the detected temperature Th immediately before the completion of boiling. However, even if six or more feed water temperatures are set, the same operation and effect as those of this embodiment can be obtained. Can be

(Embodiment 5) FIG. 12 is a block diagram of a heat pump water heater according to a fifth embodiment of the present invention, and FIG. 13 shows the relationship between the water supply temperature, the valve opening degree of the pressure reducing device, and the discharge pressure with respect to the operation time of the heat pump water heater. It is a graph shown.

The present embodiment is different from the first embodiment in that a timer 18 is provided. Note that the portions denoted by the same reference numerals as those in the first embodiment have the same configuration, and description thereof will be omitted.

Next, the operation and operation will be described. FIG.
The horizontal axis shows the degree of operation time, and the vertical axis shows the relationship between the feed water temperature, the valve opening of the pressure reducing device, and the discharge pressure with respect to the operating time, taking the feed water temperature, the valve opening of the pressure reducing device, and the discharge pressure. It is a thing. As described above, the feedwater temperature rises with the operation time in the hot water / water mixture layer. In the figure,
The dotted line shows the case where the valve opening of the pressure reducing device 3 is fixed, and the discharge pressure increases rapidly as the operation time elapses and the feedwater temperature increases. Therefore, when the supply water temperature becomes equal to the detected temperature Th immediately before the completion of boiling, the valve opening of the pressure reducing device 3 is increased at predetermined preset time intervals ΔT. By doing so, the discharge pressure can be reduced as compared with the case where the valve opening of the pressure reducing device 3 is constant as shown in FIG.

That is, the control means 12 periodically supplies the feedwater temperature detecting means 8 which is the detecting means 13 immediately before the completion of boiling.
From the water supply temperature. Then, the water supply temperature detecting means 8
If the feed water temperature obtained from the above is higher than the detected temperature Th immediately before the completion of boiling, the valve opening of the pressure reducing device 3 is opened at predetermined time intervals ΔT by a signal from the timer 18.

As described above, in the present embodiment, the control means 12 for changing the valve opening of the pressure reducing device 3 at predetermined time intervals is provided, so that the optimum pressure reduction immediately before the completion of boiling is provided. Since the opening degree of the valve of the device 3 is changed, the hot water capacity of the hot water storage tank 5 can be effectively used, and an efficient hot water supply heating operation can be performed.

(Embodiment 6) FIG. 14 is a block diagram of a heat pump water heater according to Embodiment 6 of the present invention, and FIG. 15 is a graph showing the relationship between the water supply temperature, the valve opening degree of the pressure reducing device, and the discharge pressure with respect to the operation time of the heat pump water heater. It is a graph shown.

The present embodiment is different from the fifth embodiment in that a time interval storage means 19 is provided. Note that the portions denoted by the same reference numerals as those of the fifth embodiment have the same configuration,
Description is omitted.

Next, the operation and operation will be described. FIG.
The horizontal axis shows the degree of operation time, and the vertical axis shows the relationship between the feed water temperature, the valve opening of the pressure reducing device, and the discharge pressure with respect to the operating time, taking the feed water temperature, the valve opening of the pressure reducing device, and the discharge pressure. It is a thing. As described above, the feedwater temperature rises with the operation time in the hot water / water mixture layer. In the figure,
The dotted line shows the case where the valve opening of the pressure reducing device 3 is fixed, and the discharge pressure increases rapidly as the operation time elapses and the feedwater temperature increases. Therefore, when the feedwater temperature becomes the detected temperature Th1 immediately before the completion of the first boiling, the valve opening of the pressure reducing device 3 is increased at every predetermined first time interval ΔT1. Then, when the feed water temperature rises and the feed water temperature becomes the detected temperature Th2 immediately before the completion of the second boiling, a predetermined second time interval ΔT2 (ΔT2 <ΔT1) smaller than the first time interval ΔT1. ), The valve opening of the pressure reducing device 3 is increased. As described above, if the time interval for correcting the valve opening of the pressure reducing device 3 is shortened at the time of high supply water temperature at which the discharge pressure rises rapidly, as shown in FIG. As compared with, the discharge pressure can be reduced, and in particular, since a sharp increase in the discharge pressure can be eliminated,
The range of the hot water supply heating operation can be expanded. by the way,
The above-mentioned first time interval ΔT1 and second time interval ΔT2
Are stored in the time interval storage means 19.

That is, the control means 12 periodically supplies the feedwater temperature detecting means 8 which is the detecting means 13 immediately before the completion of boiling.
From the water supply temperature. Then, the water supply temperature detecting means 8
If the feed water temperature obtained from the above is higher than the first detected temperature Th1 immediately before the completion of boiling, the first time interval ΔT1 is detected by the signal from the time interval storage means 19. And
According to the signal from the timer 18, the first time interval ΔT
The valve opening of the pressure reducing device 3 is opened every one. Further, if the feed water temperature rises and the feed water temperature obtained from the feed water temperature detecting means 8 is higher than the second detected temperature immediately before the completion of the boiling Th2, the second time interval ΔT2 Is detected. Then, in response to a signal from the timer 18, the valve opening of the pressure reducing device 3 is opened at every second time interval ΔT2.

As described above, in this embodiment, by providing the control means for reducing the time interval for changing the valve opening of the pressure reducing device as the boiling is completed, the discharging is performed as the boiling is completed. When the pressure rise is large, the change in the valve opening of the pressure reducing device is increased to greatly reduce the discharge pressure, and the optimal valve opening of the pressure reducing device is changed, so that the hot water capacity of the hot water tank can be used effectively, In addition, an efficient hot water supply heating operation can be performed.

Further, in this embodiment, two time intervals ({T1 and {T1}) are used as time intervals for changing the valve opening of the pressure reducing device.
Although T2) is set, the same operation and effect as in the present embodiment can be obtained even if three or more time intervals are set.

(Embodiment 7) FIG. 16 is a block diagram of a heat pump water heater according to Embodiment 7 of the present invention, and FIG. 17 is a diagram showing the water supply temperature, the opening degree of the flow regulating valve, the flow rate, and the discharge pressure with respect to the operation time of the heat pump water heater. It is a graph which shows the valve opening degree of a pressure reducing device. The present embodiment is different from the first embodiment in that a time measuring means 20 for measuring the time when the flow passing through the flow regulating valve 11 is the maximum flow is provided as the detecting means 13 immediately before the completion of boiling. It is that you are. In addition,
Portions denoted by the same reference numerals as in the first embodiment have the same configuration, and description thereof will be omitted.

Next, the operation and operation will be described. FIG.
Takes the operation time degree on the horizontal axis, the feed water temperature, the opening degree and flow rate of the flow control valve 11, the discharge pressure, and the valve opening degree of the pressure reducing device 3 on the vertical axis. 11
The relationship between the opening degree, the flow rate, the discharge pressure, and the valve opening degree of the pressure reducing device 3 is shown. As described above, the flow control means 10 controls the opening degree of the flow control valve 11 by the signal from the boiling temperature detecting means 9 provided at the water-side outlet of the refrigerant-to-water heat exchanger 2, and The outlet water temperature (boiling temperature) of the heat exchanger 2 is raised so as to be substantially constant. Now, in the part of the hot and cold water mixing layer, the feed water temperature rises with the operation time, so the opening degree of the flow control valve 11 is increased so that the water flow rate of the refrigerant to the water heat exchanger 2 increases. However, even when the opening of the flow control valve 11 reaches the maximum opening, the supply water temperature may still rise. In this case, the boiling temperature, which is the outlet water temperature of the refrigerant-to-water heat exchanger 2, rises, and the discharge pressure also rises sharply. Therefore, the flow control valve 1
If the opening degree of No. 1 reaches the maximum opening degree continuously for a predetermined operation time, if the opening degree of the valve of the pressure reducing device 3 is controlled, the discharge pressure is reduced as shown in FIG. It is possible to continue.

That is, the control means 12 periodically detects the time when the opening of the flow regulating valve 11 is at the maximum opening from the time measuring means 20 which is the detecting means 13 immediately before completion of boiling. If the detected time is longer than a predetermined operation time set in advance, the valve opening of the pressure reducing device 3 is opened by a signal from the time measuring means 20.

As described above, the present embodiment is provided with the time measuring means for measuring the time when the opening of the flow regulating valve 11 is maximized as the detecting means immediately before the completion of boiling, so that the predetermined time can be obtained. During a period of time, it detects that the flow passing through the flow control valve 11 has reached the maximum flow, changes the valve opening of the pressure reducing device, keeps the discharge pressure low, and continues the heating operation. The hot water supply heating operation is possible up to this, and the hot water capacity of the hot water storage tank can be used effectively.

(Eighth Embodiment) FIG. 18 is a block diagram of a heat pump water heater according to an eighth embodiment of the present invention, and FIG. 19 shows the water supply temperature, discharge pressure, and valve opening degree of the pressure reducing device with respect to the operation time of the heat pump water heater. It is a graph shown. In this embodiment,
The difference from the first embodiment is that the discharge pressure detecting means 21 for detecting the discharge pressure is provided as the detection means 13 immediately before the completion of boiling. Note that the portions denoted by the same reference numerals as those in the first embodiment have the same configuration, and description thereof will be omitted.

Next, the operation and operation will be described. FIG.
The horizontal axis indicates the operation time, and the vertical axis indicates the supply water temperature, the discharge pressure, and the valve opening of the pressure reducing device, and indicates the relationship between the water supply temperature, the discharge pressure, and the valve opening of the pressure reduction device with respect to the operation time. Things. As described above, in the hot and cold water mixing layer, the feed water temperature increases with the operation time, and the discharge pressure also increases accordingly. Therefore, when the discharge pressure reaches the reference pressure P, the valve opening of the pressure reducing device 3 is increased. As a result, the discharge pressure can be reduced.

That is, the control means 12 periodically controls the discharge pressure detecting means 2 as the detecting means 13 immediately before the completion of boiling.
From 1, the discharge pressure is detected. Then, if the discharge pressure obtained from the discharge pressure detecting means 21 is higher than a preset reference pressure P, the valve opening of the pressure reducing device 3 is opened by a signal from the discharge pressure detecting means 21. And this is repeated.

As described above, in the present embodiment, the discharge pressure detecting means is used as the detecting means immediately before the completion of boiling,
By providing control means for opening the valve opening of the pressure reducing device when the set reference pressure is reached, the hot water capacity of the hot water storage tank can be used effectively, and the pressure is controlled by direct pressure, so that the compression This will surely improve the durability of the machine.

(Embodiment 9) FIG. 20 is a block diagram of a heat pump water heater according to a ninth embodiment of the present invention, and FIG. 21 is a diagram showing the operating state of the compressor, the valve opening degree and discharge of the pressure reducing device with respect to the operation time of the heat pump water heater. It is a graph which shows pressure and the lower part temperature of a hot-water storage tank.

The present embodiment is different from the first embodiment in that a hot water tank temperature detecting means 22 for detecting a lower temperature of the hot water tank is provided as a means for detecting immediately before the completion of boiling. Note that the portions denoted by the same reference numerals as those in the first embodiment have the same configuration, and description thereof will be omitted.

Next, the operation and operation will be described. FIG.
Takes the operating time on the horizontal axis, the operating state of the compressor 1, the valve opening degree of the pressure reducing device 3, the discharge pressure, and the lower temperature of the hot water tank 5 on the vertical axis, and the operating state of the compressor 1 with respect to the operating time. And the relationship between the valve opening degree of the pressure reducing device 3, the discharge pressure, and the lower temperature of the hot water tank 5. As described above, the temperature of the lower part of the hot water storage tank 5 rises with the operation time when it comes to the hot and cold water mixed layer. Then, when the hot water tank temperature detecting means 22 which is the detecting means 13 immediately before the completion of the boiling detects the detected temperature Th immediately before the completion of the boiling, the control means 12 increases (opens) the valve opening of the pressure reducing device 3. At this time, the discharge pressure decreases from P1 to P2. Thereafter, as the operation time elapses, the lower temperature of the hot water tank 5 further rises, and the discharge pressure rises accordingly. Then, when the hot water tank temperature detecting means 22 detects the lower temperature T3a of the hot water tank 5 at which the normal upper limit pressure P is reached, the compressor is stopped and the heating operation ends. The thick dotted line in the figure is the case of the conventional example in which the valve opening of the pressure reducing device 3 is not controlled. The lower temperature of the hot water storage tank 5 at the operation limit increases from T3 to T3a, and the operation range increases.

As described above, in the present embodiment, the hot-water tank temperature detecting means is used as the detecting means immediately before the completion of boiling, and when the temperature of the hot-water tank exceeds a predetermined value, the valve opening of the pressure reducing device is opened. With the control means, the hot water capacity of the hot water storage tank can be used effectively, and the temperature of the hot water storage tank is directly detected and controlled, so that the durability of the compressor is more reliably improved.

[0067]

As described above, according to the first to ninth aspects of the present invention, the valve opening of the pressure reducing device is controlled when the discharge pressure of the compressor rises near the completion of boiling. In addition, since the discharge pressure is kept low and the hot water supply heating operation can be performed up to a high supply water temperature, a wasteful area that cannot be used as effective hot water is reduced, and the hot water capacity of the hot water storage tank can be effectively used. As a result, a hot water tank of the same size as the conventional one can satisfy a larger hot water supply load, and conversely, to satisfy a hot water supply load of the same size as the conventional one, a smaller hot water tank can be used. The degree is large and the cost is reduced. Furthermore, an efficient hot water supply heating operation can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a heat pump water heater according to a first embodiment of the present invention.

FIG. 2 is a graph showing an operating state of a compressor, a valve opening degree of a pressure reducing device, a discharge pressure, and a feed water temperature with respect to an operation time of the heat pump water heater.

FIG. 3 is an explanatory diagram showing a temperature distribution of a hot water storage tank of the heat pump water heater.

FIG. 4 is a configuration diagram illustrating a heat pump water heater according to a second embodiment of the present invention.

FIG. 5 is a graph showing a discharge pressure with respect to a valve opening degree of a pressure reducing device of the heat pump water heater.

FIG. 6 is a graph showing a change amount of a valve opening of a pressure reducing device with respect to an outside air temperature of the heat pump water heater and a detected temperature immediately before completion of boiling.

FIG. 7 is a configuration diagram illustrating a heat pump water heater according to a third embodiment of the present invention.

FIG. 8 is a graph showing a feed water temperature, a discharge pressure, a valve opening degree of a pressure reducing device, and an operating state of a compressor with respect to an operation time of the heat pump water heater.

FIG. 9 is a configuration diagram illustrating a heat pump water heater according to a fourth embodiment of the present invention.

FIG. 10 is a graph showing a discharge pressure and a valve opening of a pressure reducing device with respect to a water supply temperature of the heat pump water heater.

FIG. 11 is a graph showing a change amount of a valve opening degree of a pressure reducing device with respect to a water supply temperature of the heat pump water heater.

FIG. 12 is a configuration diagram illustrating a heat pump water heater according to a fifth embodiment of the present invention.

FIG. 13 is a graph showing a feed water temperature, a valve opening degree of a pressure reducing device, and a discharge pressure with respect to an operation time of the heat pump water heater.

FIG. 14 is a configuration diagram showing a heat pump water heater according to Embodiment 6 of the present invention.

FIG. 15 is a graph showing a feed water temperature, a valve opening degree of a pressure reducing device, and a discharge pressure with respect to an operation time of the heat pump water heater.

FIG. 16 is a configuration diagram showing a heat pump water heater according to a seventh embodiment of the present invention.

FIG. 17 is a graph showing the feed water temperature, the opening degree of the flow control valve, the flow rate, the discharge pressure, and the opening degree of the pressure reducing device with respect to the operation time of the heat pump water heater.

FIG. 18 is a configuration diagram illustrating a heat pump water heater according to an eighth embodiment of the present invention.

FIG. 19 is a graph showing a feed water temperature, a discharge pressure, and a valve opening degree of a pressure reducing device with respect to an operation time of the heat pump water heater.

FIG. 20 is a configuration diagram showing a heat pump water heater according to a ninth embodiment of the present invention.

FIG. 21 is a graph showing the operation state of the compressor, the valve opening degree of the pressure reducing device, the discharge pressure, and the lower temperature of the hot water tank with respect to the operation time of the heat pump water heater.

FIG. 22 is a configuration diagram showing a heat pump water heater in a conventional example.

FIG. 23 is an explanatory diagram showing a temperature distribution of a hot water storage tank of the heat pump water heater.

FIG. 24 is a graph showing discharge pressure with respect to feed water temperature of the heat pump water heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Refrigerant-water heat exchanger 3 Decompression device 4 Evaporator 5 Hot water storage tank 6 Circulation pump 10 Flow control means 11 Flow control valve 12 Control means 13 Detecting means just before completion of boiling

Claims (9)

[Claims] 1. A refrigerant circuit in which a compressor, a refrigerant-to-water heat exchanger, a pressure reducing device for controlling the flow rate of refrigerant, and an evaporator are sequentially connected, a hot water tank, a circulation pump, and the refrigerant-water heat exchanger are sequentially arranged. A connected hot water supply circuit, and a water side inlet of the refrigerant / water heat exchanger and the hot water storage tank in order to make a boiling temperature that is a water side exit water temperature of the refrigerant / water heat exchanger in the hot water supply circuit constant. A flow control means for controlling a flow control valve provided between the water-side outlet of the refrigerant-to-water heat exchanger and the hot water storage tank, and a boiler for detecting immediately before the entire hot water storage tank is heated A heat pump water heater comprising: immediately before completion detection means; and control means for changing a valve opening of the pressure reducing device when a signal from the immediately before boiling completion detection means becomes a predetermined signal. 2. The heat pump according to claim 1, further comprising control means for determining the amount of change in the valve opening of the pressure reducing device in accordance with the outside air temperature obtained from the outside air temperature detecting means for detecting the outside air temperature. Water heater. 3. A water supply temperature detection means for detecting a water supply temperature which is a water-side inlet water temperature of a refrigerant-to-water heat exchanger as a detection means immediately before the completion of boiling, wherein the water supply temperature detection means comprises a plurality of predetermined water supply waters. 2. The heat pump water heater according to claim 1, further comprising control means for controlling so as to open the valve opening of the pressure reducing device every time the temperature is detected. 4. The heat pump water heater according to claim 3, wherein the amount of change of the valve opening of the pressure reducing device is increased as the water supply temperature is higher. 5. The heat pump water heater according to claim 1, further comprising control means for changing a valve opening of the pressure reducing device at predetermined time intervals. 6. The time interval for changing the valve opening of the pressure reducing device is as follows:
6. The heat pump water heater according to claim 5, wherein the heat pump water heater is reduced as the boiling is completed. 7. As a means for detecting immediately before the completion of boiling, a time measuring means for measuring a time during which the maximum flow rate is reached when the flow rate passing through the flow regulating valve reaches the maximum flow rate is provided. Item 2. The heat pump water heater according to item 1. 8. The heat pump water heater according to claim 1, further comprising a discharge pressure detecting means for detecting a discharge pressure as a means for detecting immediately before the completion of boiling. 9. The heat pump water heater according to claim 1, further comprising a hot water tank temperature detecting means for detecting a lower temperature of the hot water tank as a means for detecting immediately before the completion of boiling.