JP2001208434A - Heat pump hot water supplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump hot water supplier which improves the operation efficiency and the durability. SOLUTION: This hot water supplier is equipped with a refrigerant circulating circuit where a compressor 1, a refrigerant-to-water heat exchanger 2, a depressurizer 3, and an evaporator 4 are connected in order, a hot water supply circuit where a hot water reservoir 5, a circulating pump 6, and a refrigerant-to- water heat exchanger 2 are connected in order, a discharge temperature detection means 12 which detects the discharge temperature of the compressor 1, and a control means 11 which controls the aperture of the depressurizer 3 so that it may be the preset objective discharge temperature, and further the aperture of the above depressurizer is minimized, so this hot water supplier can perform stable efficient hot water supply heating operation.

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. 44 is a configuration diagram of a conventional heat pump water heater. In FIG. 44, a compressor 1, a refrigerant-to-water heat exchanger 2,
The compressor 1 comprises a refrigerant circulation circuit including a pressure reducing device (capillary tube) 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. The discharged high-temperature and 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. 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 water in the lower part of the hot water storage tank 5 is rotated by the rotation speed control means 9 so that the boiling temperature obtained by the boiling temperature detection means 8 provided at the water-side outlet of the refrigerant-to-water heat exchanger 2 becomes substantially constant. Circulating pump 6 controlled by
Thus, the hot water is sent to the upper portion of the hot water storage tank 5 and gradually stored from above. Then, when the inlet water temperature of the refrigerant-to-water heat exchanger 2 reaches a set value, the inlet water temperature detecting means 10 detects, and stops the heat pump operation by the compressor 1,
The operation is switched to the independent operation of the auxiliary heater 7.

The conventional heat pump water heater shown in FIG. 44 uses a capillary tube as the pressure reducing device 3.

There is also a conventional heat pump water heater in which an automatic temperature expansion valve is used as the pressure reducing device 3.
FIG. 45 shows this second conventional example. In the same figure, 3a
Is a main body of the temperature automatic expansion valve, and 3b is a temperature sensing cylinder of the temperature automatic expansion valve. Note that components having the same reference numerals as those in the first embodiment shown in FIG. 44 have the same structure, and description thereof will be omitted.

[0005]

As described above, the water in the lower part of the hot water storage tank 5 is supplied to the hot water storage tank 5 by the circulation pump 6 controlled by the rotation speed control means 9 so that the boiling temperature is substantially constant. It is sent to the upper part of 5 and is gradually stored from the top. However, for a while after starting the hot water supply operation, the temperature of the entire refrigerant circuit (particularly the discharge temperature of the compressor 1)
Is low, hot water having a temperature lower than a predetermined boiling temperature is sent to the upper part of the hot water storage tank 5 and stored.

When the capillary tube 3 is used as a decompression device, the specifications of the capillary tube 3 are generally designed on the basis of summer temperature conditions where a large amount of refrigerant circulates. For this reason, in the winter, when the outside air temperature is low, especially in the winter, the excess refrigerant is circulated in the refrigerant circuit. Therefore, after starting the hot water supply operation, the discharge temperature of the compressor 1 does not easily rise. However, hot water having a considerably low temperature may be stored in the hot water storage tank 5. For this reason,
The high-temperature hot water stored in the hot-water storage tank 5 and the low-temperature hot water may be mixed, and the temperature of the hot water stored in the hot-water storage tank 5 may be considerably reduced. There was a problem that cutting occurred. In addition, there is also a problem that the operating efficiency is reduced because the circulation amount of the refrigerant is too large.

When the hot water supply operation is performed in winter, frost may be formed on the evaporator 4. In the case of the capillary tube 3, since the amount of circulating refrigerant cannot be adjusted, the discharge temperature sharply drops with frost. For this reason, a predetermined boiling temperature cannot be obtained, and hot water having a low temperature may be stored in the hot water storage tank 5. For this reason, there is a problem that hot water runs out on a day when the hot water supply load is large in winter.

On the other hand, in the second conventional example shown in FIG. 45, when an automatic temperature expansion valve 3 is used as a pressure reducing device, generally,
The specifications of the automatic temperature expansion valve 3 as a pressure reducing device are designed so that the refrigerant at the outlet of the evaporator 4 is in a superheated gas state with a superheat degree. By the way, after starting the hot water supply operation, the evaporation pressure is low for a while because the suction pressure of the compressor 1 is low. However, the temperature near the temperature-sensitive cylinder 3b of the automatic temperature expansion valve 3 is higher than the saturation temperature of the evaporating pressure (the temperature is delayed in response to the fluctuation of the pressure drop). Since the degree of superheat increases, the operation is performed to open the opening of the automatic temperature expansion valve 3. As a result, since more refrigerant than necessary is circulated in the refrigerant circuit, the discharge temperature of the compressor 1 does not readily rise after the hot water supply operation is started. There was a problem that.

Further, since there is a response delay between the pressure change of the main body 3a of the temperature automatic expansion valve 3 and the temperature change of the temperature sensing cylinder 3b, the pressure and the temperature of the refrigerant circuit are reduced when the hot water supply operation is started. May hunt greatly. For this reason, the pressure and the temperature may exceed the upper limits of the normal pressure and the normal temperature, and the durability of the compressor 1 is deteriorated.

When the hot water supply operation is performed in winter, frost may be formed on the evaporator 4. In this case, the temperature automatic expansion valve 3
In order to make the refrigerant at the outlet of the evaporator 4 a superheated gas with a superheat degree, the opening degree of the valve is reduced so that the refrigerant circulation amount is reduced as the frost progresses. For this reason, there is also a problem that a required amount of the circulating refrigerant cannot be obtained and the operating efficiency is reduced.

An object of the present invention is to reduce the temperature drop of hot water storage tank 5 due to the mixing of low-temperature hot water during hot water supply operation and to improve the efficiency during hot water supply operation.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention solves the above-mentioned problems by providing a refrigerant circulation circuit in which a compressor, a refrigerant-to-water heat exchanger, a depressurizing device capable of adjusting an opening degree, and an evaporator are sequentially connected. A tank, a circulating pump, a hot water supply circuit in which the refrigerant-to-water heat exchanger is sequentially connected, a discharge temperature detecting means for detecting a discharge temperature of the compressor, and the pressure reducing device of the decompression device so as to reach a preset target discharge temperature. Control means for controlling the opening degree, wherein a minimum valve opening degree is provided for the opening degree of the pressure reducing device.

In the above invention, since the discharge valve is controlled by providing the minimum valve opening to the opening of the pressure reducing device, the opening of the pressure reducing device does not become smaller than necessary. Can be smaller. As a result, hot water having a predetermined boiling temperature is obtained immediately after the start of operation, and the hot water is stored in the hot water storage tank 5.
There is an effect that the temperature of the hot water stored in the hot water is not lowered and the hot water does not run out even on a day when the hot water supply load is large in winter.

In addition, since the amount of circulating refrigerant is controlled, there is an effect that the amount of circulating refrigerant is not excessively large or small and the operating efficiency is improved.

Furthermore, since the hunting of pressure and temperature at the time of starting operation is small, the pressure and temperature do not exceed the upper limits of the normal pressure and the normal temperature, and the durability of the compressor is improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be embodied in the form described in each claim. As described in claim 1, a compressor, a refrigerant-to-water heat exchanger, a decompression device capable of adjusting the opening degree. A refrigerant circuit in which evaporators are sequentially connected, a hot water tank, a circulation pump, and a hot water supply circuit in which the refrigerant-to-water heat exchanger is sequentially connected,
Discharge temperature detecting means for detecting a discharge temperature of the compressor,
Control means for controlling the degree of opening of the pressure reducing device so as to reach a preset target discharge temperature, and by providing the minimum valve opening to the degree of opening of the pressure reducing device, the discharge temperature rises quickly. Also, since the hunting between the pressure and the temperature of the refrigerant circuit can be reduced, hot water having a predetermined boiling temperature can be obtained immediately after the start of operation, and a required amount of circulating refrigerant can be obtained. This has the effect of improving the efficiency of time.

Further, the required amount of circulating refrigerant can be obtained by changing the minimum valve opening of the pressure reducing device in accordance with the outside air temperature, so that the efficiency in hot water supply operation is improved. In addition, there is an effect that hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

Further, the required amount of circulating refrigerant can be obtained by changing the minimum valve opening of the pressure reducing device in accordance with the feed water temperature, thereby improving the efficiency of the hot water supply operation. In addition, there is an effect that hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

Further, as described in claim 4, after the hot water detecting means detects hot water, the water supply temperature detecting means detects the water supply temperature.

Further, by changing the minimum valve opening of the pressure reducing device between the start of operation and the steady state, the required amount of circulating refrigerant according to the conditions can be ensured. Also, there is an effect that the hot water supply operation efficiency is improved also in the case of frost formation or frost formation.

Further, since the minimum valve opening of the pressure reducing device differs depending on the power supply frequency, a required amount of refrigerant circulating according to the power supply frequency can be ensured. Also in the case of time, there is an effect that the hot water supply operation efficiency is improved.

In the case where the hot start determining means for judging whether the compressor is warm or not detects the hot start, the start-up minimum valve of the pressure reducing device is provided. By increasing the opening degree, a required amount of circulating refrigerant can be secured, so that there is an effect that the efficiency at the time of starting hot water supply operation is improved.

According to the present invention, a compressor temperature detecting means is used as the hot-time judging means.

According to a ninth aspect of the present invention, a first time integrating means for integrating the elapsed time from the previous operation stop is used as the hot time determining means.

According to a tenth aspect of the present invention, a second time integrating means for integrating the elapsed time after the start of the operation and a discharge temperature detecting means are used as the hot-time determining means. As described, the required circulating refrigerant amount can be obtained by changing the startup minimum valve opening of the pressure reducing device according to the outside air temperature at the time of hot operation startup, so that the predetermined boiling immediately after the operation startup. There is an effect that hot water at a temperature can be obtained.

Further, the required circulating refrigerant amount can be obtained by changing the minimum valve opening of the pressure reducing device at the start of operation in a hot state according to the feed water temperature. There is an effect that hot water having a predetermined boiling temperature can be obtained immediately after the start.

According to a thirteenth aspect of the present invention, there is provided a dead zone time for fixing the opening of the pressure reducing device at the start-up initial valve opening which is equal to or greater than the minimum valve opening at the time of starting operation. Since the hunting between the pressure and the temperature of the circuit can be reduced, the pressure and the temperature do not exceed the upper limits of the normal pressure and the normal temperature, and the durability of the compressor is improved.

Further, by changing the opening degree of the starting valve in accordance with the outside air temperature, a required amount of the circulating refrigerant can be obtained. There is an effect that hot water can be obtained.

Further, since the required discharge temperature can be obtained by changing the dead zone time according to the outside air temperature, the hunting between the pressure and the temperature of the refrigerant circuit can be reduced. The pressure and the temperature do not exceed the upper limits of the normal pressure and the normal temperature, and the durability of the compressor is improved.

Further, as described in claim 16, the required amount of refrigerant circulating can be secured by increasing the opening of the initial valve at the time of heating when the temperature is hot, so that there is an effect that the efficiency at the time of starting the hot water supply operation is improved.

Further, the required amount of refrigerant circulating can be obtained by changing the opening degree of the initial valve in a hot state in accordance with the outside air temperature obtained by a signal from the outside air temperature detecting means. Therefore, there is an effect that hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

Further, as described in claim 18, as the start steady state determining means, a start elapsed time measuring means for measuring an elapsed time from the start of operation is used.

According to a nineteenth aspect of the present invention, a discharge temperature detecting means and a discharge temperature change detecting means are used as the starting steady state determining means.

According to a twentieth aspect of the present invention, the starting steady-state determining means uses a boiling temperature detecting means and a boiling temperature change detecting means.

[0035]

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 a discharge diagram of the heat pump water heater with respect to a time after the start of operation when there is no restriction on the valve opening. FIG. 3 is an explanatory diagram showing the relationship between the temperature and the valve opening. FIG. 3 shows the discharge temperature and the valve opening with respect to the time after the start of operation when the lower limit (starting minimum valve opening) is provided for the valve opening of the heat pump water heater. FIG. 4 is an explanatory diagram showing a change in boiling temperature with respect to a time after the start of operation of the heat pump water heater, and FIG. 5 is a valve opening and discharge with respect to a time after frost formation of the heat pump water heater. It is explanatory drawing which shows the change of temperature and hot-water supply heating capacity. FIG. 44 described in the first conventional example.
The same reference numerals are used for the same components as described above, and the description is omitted.

In FIG. 1, the rotation speed control means 9 controls the rotation speed of the circulating pump 6 by a signal from the boiling temperature detecting means 8 provided at the 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. The control means 11 controls the valve opening of the pressure reducing device 3 based on a signal from the discharge temperature detecting means 12 for detecting the discharge temperature of the compressor 1. In addition, 13
Is a first storage unit that stores a predetermined target discharge temperature, and 14 is a second storage unit that stores a lower limit value (minimum valve opening) of the opening of the pressure reducing device 3. . When hot water is supplied from hot water outlet 15, water is supplied to hot water storage tank 5 from water supply port 16. The pressure reducing device 3 includes an electric expansion valve (not shown) and the like.

Next, the operation and operation will be described.

One way to obtain a high boiling temperature is to use high-temperature superheated steam discharged from the compressor 1. If the temperature of the high-temperature superheated steam is effectively used, the discharge pressure of the compressor 1 can be reduced. Therefore, in the heat pump water heater according to the first embodiment of the present invention, the valve opening of the pressure reducing device 3 is adjusted to control the refrigerant circulation amount in order to keep the discharge temperature at a high temperature.

To increase the discharge temperature, the opening of the pressure reducing device 3 may be narrowed (decreased), and to be lowered, the opening of the pressure reducing device 3 may be opened (increased). For example, the decompression device 3
There is an electric expansion valve (not shown) driven by a stepping motor. In this type of electric expansion valve, the valve opening increases in proportion to the number of input pulses. Now, as a method for adjusting the valve opening of the electric expansion valve as the pressure reducing device 3 in order to maintain the discharge temperature at a high temperature, there is the following method.

Assuming that the target discharge temperature is Ts, the current discharge temperature is T, and the current valve opening of the electric expansion valve (the total number of pulses input to the electric expansion valve from fully closed) is K, only the following values are obtained. What is necessary is just to correct from the present valve opening degree K of the electric expansion valve.
A × (T−Ts) (1) where A is a constant. However, if the value of equation (1) is positive, the direction is to open the valve, and if negative, the direction is to close the valve. become. Therefore, the valve opening of the electric expansion valve after the correction is as follows.

K + A × (T−Ts) (2) However, when the operation is started, the temperature of the entire refrigerant circuit is low, so that the temperature rise is much slower than the increase in the pressure of the refrigerant circuit. Become. In particular, the discharge temperature of the compressor 1 rises slowly. Now, assuming that the valve opening K of the electric expansion valve as the pressure reducing device 3 is corrected at the start of the operation as shown in the equation (1), the result is as shown in FIG.

In FIG. 2, the horizontal axis indicates the time after the start of operation, and the vertical axis indicates the valve opening and discharge temperature of the electric expansion valve as the pressure reducing device 3 at that time. 4 shows a relationship between a valve opening degree of a valve and a discharge temperature. That is, the control unit 11 detects the discharge temperature of the compressor 1 based on the signal from the discharge temperature detection unit 12 at every measurement time interval ΔT after the operation is started, and the valve of the pressure reducing device 3 is controlled by the control amount determined by the equation (1). 7 shows changes in the discharge temperature and the valve opening of the pressure reducing device when the opening is corrected. As can be seen from the figure, since the discharge temperature of the compressor 1 is low immediately after the start of operation, the pressure reducing device 3
Since the valve opening degree of the valve continues to be rapidly reduced, the discharge temperature further increases even if the discharge temperature reaches the target discharge temperature. Therefore, the valve opening of the pressure reducing device 3 is kept sharply increased in order to lower the discharge temperature, so that the temperature becomes considerably lower than the target discharge temperature. As described above, the discharge temperature largely hunts up and down. The pressure also largely hunts up and down similarly to the discharge temperature.

Therefore, as shown in FIG. 3, the valve opening of the pressure reducing device 3 is provided with a minimum valve opening. That is, the control unit 11 detects the discharge temperature of the compressor 1 based on the signal from the discharge temperature detection unit 12 at every measurement time interval ΔT after the start of operation, and corrects the valve opening of the pressure reducing device 3 according to the equation (1). Find the quantity. At this time, if the corrected valve opening of the pressure reducing device 3 obtained by Expression (2) is larger than the minimum valve opening, the valve opening of the pressure reducing device 3 is set to the valve opening obtained by Expression (2). Conversely, if it is smaller than the minimum valve opening, the valve opening of the pressure reducing device 3 is set to the minimum valve opening. With this configuration, a minimum refrigerant circulation amount at the time of startup can be ensured, so that hunting of the discharge temperature at the time of startup of the operation can be minimized.

At the discharge temperature shown in the figure, the solid line is the case of this embodiment, and the one-dot chain line and the dotted line are the case of the capillary tube and the automatic temperature expansion valve shown in the first and second conventional examples. As can be seen from the comparison in the figure, in the case of the present embodiment, hunting of the discharge temperature is smaller than in the automatic temperature expansion valve, and the discharge temperature rises faster than in the automatic temperature expansion valve and the capillary tube. As a result, as shown in FIG. 4, the rise of the boiling temperature is also accelerated. FIG. 4 shows the change of the boiling temperature with respect to the time after the start of operation, with the horizontal axis indicating the time after the start of operation and the vertical axis indicating the boiling temperature. Also in this figure, the solid line is the case of this embodiment, and the one-dot chain line and the dotted line are the case of the capillary tube and the automatic temperature expansion valve shown in the first and second conventional examples.

FIG. 5 shows the characteristics when frost forms on the evaporator 4 when the outside air temperature in winter is low. That is, the horizontal axis indicates the time after frosting, and the vertical axis indicates the valve opening degree, discharge temperature, and hot water heating capacity of the pressure reducing device 3, and the valve opening degree, discharge temperature, and hot water supply heating time with respect to the time after frosting. It shows a change in ability. When the outside air temperature is low, frost may form on the evaporator 4 and the frost may grow. In this case, since the amount of heat absorbed by the evaporator 4 from the atmosphere decreases with time, the discharge temperature tends to decrease. In order to make it reach the target discharge temperature, the valve opening of the pressure reducing device 3 is reduced as shown in FIG. However, as the valve opening degree is reduced, the amount of circulating refrigerant decreases, and the hot water supply heating capacity also decreases.
When the valve opening degree is further reduced as the frost amount increases, the refrigerant circulation amount sharply decreases, and the hot water supply heating capacity also sharply decreases. Therefore, if the valve opening of the pressure reducing device 3 becomes the minimum valve opening that becomes the minimum required refrigerant circulation amount, the valve opening of the pressure reducing device 3 is not further reduced, and the hot water supply heating capability by frost formation is provided. Is smaller than when the valve opening is narrowed below the minimum valve opening. Also in this figure, the solid line is the case of this embodiment, and the one-dot chain line and the dotted line are the case of the capillary tube and the automatic temperature expansion valve shown in the first and second conventional examples. In the case of this embodiment,
It can be seen that the decrease in the hot water supply heating capacity is smaller than in the case of the capillary tube or the automatic temperature expansion valve shown in the first and second conventional examples.

As described above, since the discharge temperature is controlled so that the opening of the pressure reducing device does not become smaller than the minimum valve opening at the time of starting operation, the discharge temperature rises quickly, and the pressure and temperature of the refrigerant circuit are increased. Hunting can be reduced, so that hot water having a predetermined boiling temperature can be obtained immediately after the start of operation, and the durability of the compressor is improved.

In addition, even during the frosting operation in winter, for example, other than when the operation is started, control is performed so that the opening of the pressure reducing device 3 does not become smaller than the minimum valve opening, so that the minimum necessary refrigerant circulation amount can be obtained. Thus, the efficiency of the hot water supply operation is improved.

(Embodiment 2) FIG. 6 is a configuration diagram of a heat pump water heater according to Embodiment 2 of the present invention, and FIG. 7 is an explanatory diagram showing a minimum valve opening of a pressure reducing device with respect to an outside air temperature of the heat pump water heater.

This embodiment is different from the first embodiment in that an outside air temperature detecting means 17 for detecting the outside air temperature is provided, and the discharge temperature detecting means 12 and a predetermined target discharge temperature are stored. The control means 11 receives signals from the first storage means 13 and the second storage means 14 which stores the lower limit value (minimum valve opening degree) of the opening degree of the pressure reducing device 3 and the outside air temperature detecting means 17. That is to control the valve opening of the pressure reducing device 3.

The parts denoted by the same reference numerals as in the first embodiment have the same configuration, and the description is omitted.

Next, the operation and operation will be described.

The amount of heat that the evaporator 4 absorbs from atmospheric heat greatly differs depending on the outside air temperature. Therefore, the rate of increase in the discharge temperature of the compressor 1 at the time of starting the operation also differs greatly, so that the required amount of circulating refrigerant also changes.

FIG. 7 shows the relationship between the outside air temperature and the minimum valve opening by taking the outside air temperature on the horizontal axis and the minimum valve opening on the vertical axis. Now, when the valve opening degree of the pressure reducing device 3 is constant, the amount of heat absorbed by the evaporator 4 from atmospheric heat increases when the outside air temperature increases, but the refrigerant circulation amount does not increase so much, and the operating efficiency deteriorates. Then, the degree of superheat of the refrigerant sucked into the compressor 1 increases, and the discharge temperature of the compressor 1 also increases. Since it is necessary to increase the amount of the circulating refrigerant in order to keep the discharge temperature constant, the minimum valve opening is increased as the outside air temperature is increased, as shown in FIG.

Conversely, when the outside air temperature decreases, the amount of heat absorbed by the evaporator 4 from atmospheric heat decreases, but the amount of circulating refrigerant does not decrease so much, so that the degree of superheat of the refrigerant sucked into the compressor 1 decreases. In addition, the discharge temperature of the compressor 1 also decreases. As a result, the predetermined boiling temperature is not easily reached after the operation is started. To maintain the discharge temperature at a high temperature, it is necessary to reduce the amount of circulating refrigerant. Therefore, as shown in FIG. 7, when the outside air temperature decreases, the minimum valve opening is reduced.

The same can be said for the frosting operation other than the operation start-up described with reference to FIG. 7. Therefore, when the outside air temperature is high, the minimum valve opening is increased, and when the outside air temperature is low, the minimum valve opening is decreased. Set as follows.

As described above, the required amount of circulating refrigerant can be obtained by changing the minimum valve opening of the pressure reducing device 3 at the start of operation according to the outside air temperature, so that the efficiency at the start of hot water supply operation is improved. Further, hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

Further, by changing the minimum valve opening of the pressure reducing device 3 in accordance with the outside air temperature even during the frosting operation, the required amount of circulating refrigerant can be obtained, so that the efficiency in the hot water supply operation is improved, and Since the hot water having the boiling temperature can be obtained, the hot water supply load can be covered even when the outside air temperature is low.

(Embodiment 3) FIG. 8 is a block diagram of a heat pump water heater according to a third embodiment of the present invention, FIG. 9 is an explanatory diagram showing a water supply temperature with respect to an outside air temperature of the heat pump water heater, and FIG. 10 is a heat pump water heater. It is explanatory drawing which shows the minimum valve opening degree of the decompression device with respect to the supply water temperature.

The present embodiment shown in FIG. 8 is different from the first embodiment in that a feed water temperature detecting means 18 for detecting a feed water temperature is used.
The discharge temperature detecting means 12, the first storage means 13 for storing a predetermined target discharge temperature, and the lower limit value (minimum valve opening degree) of the opening of the pressure reducing device 3 are stored. The control means 11 controls the valve opening of the pressure reducing device 3 based on signals from the second storage means 14 and the feedwater temperature detecting means 18.

Note that the portions denoted by the same reference numerals as in the first embodiment have the same configuration, and description thereof will be omitted.

Generally, there is a relationship between the outside air temperature and the supply water temperature as shown in FIG. Further, from the relationship between the outside air temperature and the supply water temperature in FIG. 9 and the relationship between the outside air temperature and the minimum valve opening degree of the pressure reduction device 3 shown in FIG. 7, as shown in FIG. The relationship of the minimum valve opening is obtained.

As described in the second embodiment, the amount of heat absorbed by the evaporator 4 from atmospheric heat greatly differs depending on the outside air temperature.
Therefore, if the relationship of FIG. 10 is used, the same operation and action as in the second embodiment can be obtained by detecting the supply water temperature instead of detecting the outside air temperature, and the description is omitted.

As the water supply temperature detecting means 18, the inlet water temperature detecting means 10 may be used.

As a result, the required amount of circulating refrigerant can be obtained by changing the minimum valve opening of the pressure reducing device 3 at the start of operation in accordance with the feedwater temperature, so that the efficiency of starting the hot water supply operation is improved. Further, hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

Further, by changing the minimum valve opening of the pressure reducing device 3 in accordance with the feed water temperature even during the frosting operation, the required amount of circulating refrigerant can be obtained, so that the efficiency in the hot water supply operation is improved, and Since the hot water having the boiling temperature is obtained, the hot water supply load can be covered even when the water supply temperature, that is, the outside air temperature is low.

(Embodiment 4) FIG. 11 is a block diagram of a heat pump water heater according to a fourth embodiment of the present invention, and FIG. 12 is an explanatory diagram showing a change in temperature detected by a water supply temperature detecting means depending on whether or not the heat pump water heater is hot. It is.

In the present embodiment shown in FIG.
The difference from the first embodiment is that hot water detecting means 19 is provided.
Further, the control means 11 detects the water supply temperature by a signal from the water supply temperature detection means 18 when the water supply detection means 19 detects the hot water supply.

The parts denoted by the same reference numerals as in the first embodiment have the same configuration, and the description is omitted.

In FIG. 12, the horizontal axis represents time, and the vertical axis represents the presence or absence of hot water detected by hot water detecting means 19 and water supply temperature detecting means 1.
8 shows the change in the temperature detected by the water supply temperature detecting means 18 before and after tapping the hot water. When there is no hot water, the temperature of the portion provided with the feedwater temperature detecting means 18 is affected by the ambient temperature such as the outside air temperature because there is no flow of the feedwater. Then, when there is hot water from the hot water outlet 15, new city water enters the hot water storage tank 5 through the water supply port 16, so that the temperature of the portion provided with the water supply temperature detecting means 18 can detect the correct water supply temperature. As shown in FIG. 12, the temperature detected by the water supply temperature detecting means 18 before the point A at the start of hot water supply is the temperature t0 affected by the ambient temperature such as the outside air temperature. Then, when the hot water starts, new city water flows in, so after a while, the water supply temperature detecting means 1
The temperature of the portion provided with 8 becomes the correct feed water temperature t.
Therefore, if the water supply temperature detection means 18 detects the temperature at the time point B after the delay time T has elapsed after the hot water detection means 19 detects the hot water supply, the correct water supply temperature can be detected.

The operation and operation are the same as those of the third embodiment, and the description is omitted.

(Embodiment 5) FIG. 13 is a block diagram of a heat pump water heater according to a fifth embodiment of the present invention, FIG. 14 is an explanatory diagram showing a change in discharge temperature with respect to an elapsed time after the start of the heat pump water heater, and FIG. FIG. 4 is an explanatory diagram showing a change in discharge pressure with respect to an opening degree of a pressure reducing device in a steady state of the heat pump water heater.

This embodiment is different from the first embodiment in that the starting steady state determining means 20 for judging whether the hot water supply operation is started or in a steady state, the starting minimum valve opening storage means 14a and the steady minimum valve opening storage. The second storage means 14 comprising the means 14b is provided.

Note that the 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. 14 shows the time after the start of operation on the horizontal axis.
The vertical axis represents the discharge temperature, and shows the relationship between the change in the discharge temperature and the time after the start of operation. In the figure, as the dotted line, the solid line, and the dashed line become,
Is large (each minimum valve opening is A,
If B and C, A <B <C). The two-dot chain line indicates the maximum temperature for ordinary use. As can be seen from the figure, the smaller the minimum valve opening of the pressure reducing device 3 (minimum valve opening A), the faster the rise of the discharge temperature, but the larger the amount of hunting up and down. Conversely, the larger the minimum valve opening of the pressure reducing device 3 (the minimum valve opening C), the slower the rise of the discharge temperature but the smaller the amount of hunting up and down. Therefore, the valve opening (valve opening B) indicated by a solid line that does not exceed the normal maximum temperature that affects the durability of the compressor 1 and has a rapid rise in the discharge temperature is set to the minimum opening of the pressure reducing device 3 at the time of startup. Should be set to.

FIG. 15 shows the relationship between the valve opening of the pressure reducing device 3 and the discharge pressure in a steady state, with the horizontal axis representing the valve opening of the pressure reducing device 3 and the vertical axis representing the discharge pressure. In the same figure, the two-dot chain line indicates the normal maximum pressure. As can be seen from the figure, the discharge pressure increases as the valve opening of the pressure reducing device 3 decreases, and when the valve opening D is reached, the discharge pressure becomes equal to the normal maximum pressure. Therefore, the valve opening D may be set to the minimum valve opening of the pressure reducing device 3 in a steady state. FIG.
Is generally different from the minimum valve opening B at the time of startup in FIG.

In FIG. 13, when the steady start determination means 20 detects the startup operation, the minimum startup valve opening storage means 14a in the second storage means 14, the discharge temperature detection means 12, and the predetermined target discharge The control means 11 controls the valve opening of the pressure reducing device 3 by a signal from the first storage means 13 which stores the temperature.

When the steady start-up determining means 20 detects a steady operation, the steady-state minimum valve opening storage means 14b in the second storage means 14, the discharge temperature detecting means 12 and the predetermined target discharge temperature are stored. The control means 11 controls the valve opening of the pressure reducing device 3 based on the stored signal from the first storage means 13.

As described above, the startup operation and the steady operation are
Since the lower limit value (minimum valve opening) of the valve opening of the pressure reducing device 3 is separately set, the required amount of circulating refrigerant is always obtained, so that the efficiency of hot water supply operation is improved.

(Embodiment 6) FIG. 16 is a block diagram of a heat pump water heater according to Embodiment 6 of the present invention, and FIG. 17 is a graph showing the discharge pressure at different power supply frequencies with respect to the opening degree of the pressure reducing device in the steady state of the heat pump water heater. It is explanatory drawing which shows a change.

The present embodiment is different from the first embodiment in that a power supply frequency detecting means 21 for determining the frequency of the power supply is provided.
And a second storage means 14 for storing the minimum valve opening degree with respect to the power supply frequency, a discharge temperature detection means 12 and a first storage means 13 for storing a predetermined target discharge temperature. The means 11 is configured to control the valve opening of the pressure reducing device 3.

The portions denoted by the same reference numerals as in the first embodiment have the same configuration, and the description will be omitted.

Next, the operation and operation will be described.

FIG. 17 shows the relationship between the valve opening of the pressure reducing device 3 and the discharge pressure in a steady state, with the horizontal axis representing the valve opening of the pressure reducing device 3 and the vertical axis representing the discharge pressure. By the way, in Japan, there are generally 50 Hz and 60 Hz as commercial power supply frequencies. And even if the same heat pump water heater has a different power supply frequency, the refrigerant circulation amount is different. In the figure, the solid line indicates that the power supply frequency is 60 Hz.
The dotted line shows the case where the power supply frequency is 50 Hz. The two-dot chain line indicates the normal maximum pressure. Now, assuming that the valve opening at which the discharge pressure becomes equal to the normal maximum pressure is the minimum valve opening, the minimum valve opening is E when the power supply frequency is 60 Hz, and the minimum valve opening is F when the power supply frequency is 50 Hz ( E> F). As described above, since the lower limit (minimum valve opening) of the valve opening of the pressure reducing device 3 is set by the power supply frequency, the required amount of circulating refrigerant is always obtained, and the efficiency of the hot water supply operation is improved. .

(Embodiment 7) FIG. 18 is a configuration diagram of a heat pump water heater of Embodiment 7 of the present invention, and FIG. 19 is an explanatory diagram showing a change in discharge temperature with respect to an elapsed time after the start of the heat pump water heater.

This embodiment is different from the first embodiment in that the hot-time judging means 22 for judging when the compressor is hot and the lower limit of the opening degree of the pressure reducing device 3 when the operation is started during the hot time ( The third storage means 23 for storing the minimum valve opening during startup during heating is provided.

The portions denoted by the same reference numerals as in the first embodiment have the same configuration, and the description will be omitted.

Next, the operation and operation will be described.

FIG. 19 shows the time after the start of operation on the horizontal axis.
The vertical axis represents the discharge temperature, and shows the relationship of the change in the discharge temperature with respect to the time after the start of operation when the valve opening of the pressure reducing device 3 is kept constant. In the figure, a solid line indicates a case where the compressor 1 is warm when the operation is started, and a dotted line indicates a case where the compressor 1 is cold when the compressor 1 is cold. As can be seen from the figure, the rate of rise of the discharge temperature is higher in the hot state shown by the solid line than in the cold state shown by the dotted line. For this reason, if the minimum startup valve opening is the same between hot and cold, the discharge temperature greatly exceeds the target discharge temperature in the case of hot, and as a result, hunting increases. Therefore, the lower limit of the valve opening of the decompression device 3 for the hot start of operation is set to the hot start minimum valve opening that is larger than the start minimum valve opening of the cold start of operation. And increase the refrigerant circulation amount.

In FIG. 18, when the operation is started, the hot-time judging means 22 judges whether the compressor 1 is hot or the compressor 1 is cold. If it is hot, the signal from the third storage means 23 storing the hot start minimum valve opening degree, the signal from the first storage means 13 storing the target discharge temperature, and the discharge temperature detection means The control means 11 controls the valve opening degree of the pressure reducing device 3 with the signal from the controller 12.

In the cold state, a signal from the second storage means 14 for storing the minimum opening degree of the start valve in the cold state and a signal from the first storage means 13 for storing the target discharge temperature. The control means 11 controls the valve opening of the pressure reducing device 3 with the signal from the discharge temperature detecting means 12.

As described above, when the operation is started when the compressor 1 is hot, the lower limit valve opening of the pressure reducing device 3 (minimum valve opening during hot start) is set to the operation start during cold operation. Since the required circulating refrigerant amount is obtained because the valve opening is set to be larger than the minimum valve opening at startup, the efficiency at the time of starting hot water supply operation is improved, and the hunting of the discharge temperature can be reduced. .

(Eighth Embodiment) FIG. 20 is a configuration diagram of a heat pump water heater according to an eighth embodiment of the present invention.

This embodiment is different from the seventh embodiment in that a compressor temperature detecting means 24 is provided as the hot-time judging means 22.

The parts denoted by the same reference numerals as in the seventh embodiment have the same configuration, and the description will be omitted.

Next, the operation and operation will be described.

Referring to FIG. 20, when the operation is started, the compressor temperature detecting means 24 detects the temperature of the compressor 1. If the detected temperature is equal to or higher than a predetermined temperature (for example, 50 ° C.), it is determined to be hot, and if the detected temperature is lower than the predetermined temperature, it is determined to be cold. The following operation and operation are the same as in the seventh embodiment, and a description thereof will not be repeated.

(Embodiment 9) FIG. 21 is a configuration diagram of a heat pump water heater according to Embodiment 9 of the present invention.

The present embodiment is different from the seventh embodiment in that the hot-time judging means 22 is provided with a first time measuring means 25 for calculating an elapsed time from the previous stop of operation.

The parts denoted by the same reference numerals as in the seventh embodiment have the same configuration, and the description will be omitted.

Next, the operation and operation will be described.

In FIG. 21, when starting the operation, the first time measuring means 25 calculates the elapsed time from the previous stop of the operation. If the calculated elapsed time is shorter than a predetermined elapsed time (for example, 60 minutes), it is determined to be hot, and if the calculated elapsed time is equal to or longer than the predetermined elapsed time, it is determined to be cold. The following operation and operation are the same as in the seventh embodiment, and a description thereof will not be repeated.

(Embodiment 10) FIG. 22 shows Embodiment 1 of the present invention.
0 is a configuration diagram of the heat pump water heater, and FIG. 23 is an explanatory diagram showing a change in the discharge temperature with respect to an elapsed time after the start of the heat pump water heater.

The present embodiment is different from the seventh embodiment in that a second time measuring means 26 for calculating an elapsed time after the start of operation and a discharge temperature detecting means 12 are provided as the hot time judging means 22. That is.

The parts denoted by the same reference numerals as in the seventh embodiment have the same configuration, and the description will be omitted.

Next, the operation and operation will be described.

In FIG. 23, the horizontal axis indicates the elapsed time from the start of operation, and the vertical axis indicates the discharge temperature. The discharge temperature with respect to the elapsed time from the start of operation when the valve opening of the pressure reducing device 3 is constant. This shows the change of In the figure, a solid line indicates a case where the compressor 1 is warm when the operation is started, and a dotted line indicates a case where the compressor 1 is cold. And after the start of operation,
At the time when the discharge temperature determination time (for example, 5 minutes) has elapsed, the discharge temperature Th is set to the set discharge temperature Tset as indicated by the solid line.
If the discharge temperature Tc is lower than the set discharge temperature Tset as shown by a dotted line, it is determined as hot. The set discharge temperature Tset having such a relationship may be obtained in advance.

In FIG. 22, when the operation is started, the second time measuring means 26 calculates the elapsed time from the start of the operation. Then, when the calculated elapsed time reaches the discharge temperature determination time, the discharge temperature detecting means 12 detects the discharge temperature. If the detected discharge temperature is equal to or higher than the set discharge temperature, it is determined to be hot, and if the detected discharge temperature is lower than the set discharge temperature, it is determined to be cool. The following operation and operation are described in the seventh embodiment.
Therefore, the description is omitted.

(Embodiment 11) FIG. 24 shows Embodiment 1 of the present invention.
FIG. 25 is a configuration diagram of the heat pump water heater 1 and FIG. 25 is an explanatory diagram showing the minimum opening of the pressure reducing device (minimum opening of the hot start valve) of the pressure reducing device with respect to the outside air temperature when the heat pump water heater is hot.

The present embodiment is different from the seventh embodiment in that an outside air temperature detecting means 17 is provided.
The third storage means 23 which stores the lower limit value of the opening degree of the pressure reducing device 3 at the start of operation at the time of heating (minimum valve opening at the time of heating), the outside air temperature detection means 17 and the discharge temperature detection means 12 The control means 11 is configured to control the valve opening degree of the pressure reducing device 3 by the signal of (1).

As described in the second embodiment, even when hot, the amount of heat absorbed by the evaporator 4 from atmospheric heat differs greatly depending on the outside air temperature. Therefore, the rate of increase in the discharge temperature of the compressor 1 at the time of starting the operation also differs greatly, so that the required amount of circulating refrigerant also changes.

FIG. 25 shows the relationship between the outside air temperature and the minimum start-up valve opening during heating, with the horizontal axis indicating the outside air temperature and the vertical axis indicating the minimum start-up valve opening. Now, decompression device 3
When the outside air temperature rises while the valve opening degree is constant, the amount of refrigerant absorbed by the evaporator 4 from atmospheric heat increases, but the amount of circulating refrigerant does not increase so much, and the operating efficiency deteriorates. Then, the degree of superheat of the refrigerant sucked into the compressor 1 increases, and the discharge temperature of the compressor 1 also increases. Since it is necessary to increase the amount of circulating refrigerant in order to keep the discharge temperature constant, as shown in FIG. 25, when the outside air temperature increases, the minimum opening of the startup valve is increased.

Conversely, when the outside air temperature decreases, the amount of refrigerant circulated does not decrease so much as the amount of heat absorbed by the evaporator 4 from atmospheric heat decreases, so that the degree of superheat of the refrigerant sucked into the compressor 1 decreases. As a result, the discharge temperature of the compressor 1 also decreases. as a result,
It is not easy to reach the prescribed boiling temperature after starting operation. In order to maintain the discharge temperature at a high temperature, it is necessary to reduce the amount of the circulating refrigerant. Therefore, as shown in FIG.

As described above, the required circulating refrigerant amount can be obtained by changing the startup minimum valve opening of the pressure reducing device 3 in accordance with the outside air temperature at the start of the hot operation, so that the efficiency at the start of the hot water supply operation can be obtained. And hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

(Embodiment 12) FIG. 26 shows Embodiment 1 of the present invention.
FIG. 27 is a configuration diagram of the heat pump water heater of FIG. 2, and FIG. 27 is an explanatory diagram showing a minimum startup valve opening of the pressure reducing device during heating with respect to a water supply temperature of the heat pump water heater.

The present embodiment is different from the seventh embodiment in that a feed water temperature detecting means 18 for detecting a feed water temperature is provided, and the discharge temperature detecting means 12 and a predetermined target discharge temperature are stored. Control by signals from the first storage means 13 and the third storage means 23 which stores the lower limit value of the opening degree of the pressure reducing device 3 (minimum valve opening during hot start) and the water supply temperature detecting means 18. Means 11 is to control the valve opening of the pressure reducing device 3.

The parts denoted by the same reference numerals as in the seventh embodiment have the same configuration, and the description is omitted.

In general, the outside air temperature and the supply water temperature are
As described above, there is a relationship as shown in FIG. The relationship between the outside air temperature and the supply water temperature in FIG.
From the relationship between the outside air temperature and the start-up minimum valve opening when the pressure reducing device 3 is hot as shown in FIG. 27, the relationship between the supply water temperature and the start-up minimum valve opening when the pressure reducing device 3 is hot can be obtained as shown in FIG.

As described in the second embodiment, the amount of heat absorbed by the evaporator 4 from atmospheric heat greatly differs depending on the outside air temperature.
Therefore, by using the relationship of FIG. 27, instead of detecting the outside air temperature, the same operation and action as in the eleventh embodiment can be obtained by detecting the water supply temperature, and the description is omitted.

As the feed water temperature detecting means 18, the inlet water temperature detecting means 10 may be used.

As a result, the required circulating refrigerant amount can be obtained by changing the startup minimum valve opening of the pressure reducing device 3 in accordance with the feed water temperature when the hot operation is started, so that the efficiency in starting the hot water supply operation is reduced. As a result, hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

(Embodiment 13) FIG. 28 shows Embodiment 1 of the present invention.
3 is a configuration diagram of the heat pump water heater, and FIG. 29 is an explanatory diagram showing the relationship between the discharge temperature and the valve opening with respect to the time after the start of operation of the heat pump water heater.

The present embodiment is different from the first embodiment in that the fourth storage means 27 for storing the initial valve opening of the pressure reducing device 3 at the initial stage of operation start-up, and the pressure reducing device 3 The fifth storage means 28 which stores a predetermined dead zone time in which the valve opening is not fixed to the starting initial valve opening and the discharge temperature is not controlled, and an operation time measurement for measuring an operation time after the start. And means 29 are provided. The starting initial valve opening is set to be equal to or larger than the minimum valve opening.

That is, when the operation is started, the control means 11
Sets the valve opening of the pressure reducing device 3 to the starting initial valve opening stored in the fourth storage means 27. At the same time, the operation time measuring means 29 measures the time from the start of operation. And
If the time measured by the operation time measuring means 29 is equal to or longer than the dead zone time stored in the fifth storage means 28, the control means 11 sets the discharge temperature detecting means 12 and the target temperature as described in the first embodiment. First storage means 1 for storing the discharge temperature
3 and a signal from the second storage means 14 which stores the minimum valve opening, the opening of the pressure reducing device 3 is controlled.

In FIG. 29, the horizontal axis indicates the time after the start of operation, and the vertical axis indicates the valve opening and discharge temperature of the pressure reducing device 3.
It shows changes in the valve opening degree and discharge temperature of the pressure reducing device 3 with respect to the time after the start of operation. In the figure, after the operation is started, the valve opening of the pressure reducing device 3 is constant at the starting initial valve opening during a predetermined dead zone time. When the dead zone time ends, the control unit 11 detects the discharge temperature based on the signal from the discharge temperature detection unit 12 at every measurement time ΔT, and compares the target discharge temperature stored in the first storage unit 13 with the target discharge temperature. The valve opening of the pressure reducing device 3 is controlled according to the difference from the discharge temperature. At the discharge temperature shown in the figure, the solid line is the case of this embodiment, and the one-dot chain line and the dotted line are the case of the capillary tube and the automatic temperature expansion valve shown in the first and second conventional examples. As can be seen from the comparison in the figure, in the case of this embodiment, the hunting of the discharge temperature is smaller than in the automatic temperature expansion valve, and the discharge temperature rises faster than in the automatic temperature expansion valve and the capillary tube.

As described above, the opening of the pressure reducing device is fixed at the initial valve opening at the start of operation and the dead zone time during which the discharge temperature control is not performed is provided. Since the hunting between the pressure and the temperature of the refrigerant circuit can be reduced, hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

(Embodiment 14) FIG. 30 shows Embodiment 1 of the present invention.
4 is a configuration diagram of the heat pump water heater, and FIG. 31 is an explanatory diagram showing the initial valve opening of the decompression device with respect to the outside air temperature of the heat pump water heater.

The present embodiment is different from the thirteenth embodiment in that an outside air temperature detecting means 17 is provided.
The control unit 11 controls the pressure reducing device 3 based on a signal from the fourth storage unit 27 storing the opening of the pressure reducing device 3 during the dead zone time at the start of operation (starting valve opening) and the outside air temperature detecting unit 17. The configuration is such that the valve opening is set to the initial valve opening at startup.

As described in the second embodiment, since the amount of heat absorbed by the evaporator 4 from atmospheric heat greatly varies depending on the outside air temperature, the required refrigerant circulation amount also changes.

FIG. 31 shows the relationship between the outside air temperature and the starting initial valve opening by taking the outside air temperature on the horizontal axis and the starting initial valve opening on the vertical axis. In winter when the outside air temperature is low, the amount of heat absorbed from atmospheric heat is small, so the required amount of refrigerant circulating is small. In this case, the startup initial valve opening is reduced. On the other hand, in summer when the outside air temperature is high, the amount of heat absorbed from atmospheric heat is large, so the required amount of refrigerant circulation is large. In this case, the starting initial valve opening is increased.

As described above, by changing the initial valve opening of the pressure reducing device 3 at the start of operation in accordance with the outside air temperature, the required amount of circulating refrigerant can be obtained, so that the efficiency of starting the hot water supply operation can be improved. Also, hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

(Embodiment 15) FIG. 32 shows Embodiment 1 of the present invention.
FIG. 33 is a configuration diagram showing the heat pump water heater of FIG. 5, and FIG. 33 is an explanatory diagram showing a dead zone time at the time of startup without performing discharge temperature control on the outside air temperature of the heat pump water heater.

The present embodiment is different from the thirteenth embodiment in that the fourth storage means 27 stores the opening of the pressure reducing device 3 (starting initial valve opening) during the dead zone time at the start of operation.
The control means 11 depressurizes the signal by signals from the outside air temperature detecting means 17, the fifth storage means 28 for storing the dead zone time for the outside air temperature, and the operating time measuring means 29 for measuring the operating time after startup. The configuration is such that the valve opening of the device 3 is set to the initial valve opening of startup.

As described in the second embodiment, the amount of heat absorbed by the evaporator 4 from atmospheric heat greatly differs depending on the outside air temperature.
Further, the temperature of the compressor 1 itself is different. for that reason,
Since the rise rate of the discharge temperature of the compressor 1 at the time of starting the operation is also greatly different, the required amount of circulating refrigerant is also changed.

FIG. 33 shows the relationship between the outside air temperature and the dead zone time, with the horizontal axis representing the outside air temperature and the vertical axis representing the dead zone time at startup. In winter when the outside air temperature is low, the temperature of the compressor 1 is low at startup and the amount of heat absorbed from atmospheric heat is small, so that the discharge temperature rises very slowly. When the difference between the discharge temperature and the target discharge temperature is large,
If the discharge temperature is controlled according to this difference, the discharge temperature will largely hunt, so that the dead zone time at the time of startup is increased. On the other hand, in summer when the outside air temperature is high, the temperature of the compressor 1 is high at the time of startup and the amount of heat absorbed from atmospheric heat is large, so that the discharge temperature rises very quickly. When the difference between the discharge temperature and the target discharge temperature is relatively small, controlling the discharge temperature in accordance with this difference results in a faster discharge temperature and the target discharge temperature. Is shortened.

As described above, the required circulating refrigerant amount can be obtained by changing the dead zone time at the start of operation according to the outside air temperature, so that the efficiency at the start of hot water supply operation is improved, and Hot water having a predetermined boiling temperature can be obtained immediately.

(Embodiment 16) FIG. 34 shows Embodiment 1 of the present invention.
6 is a configuration diagram showing a heat pump water heater, and FIG. 35 is an explanatory diagram showing a change in discharge temperature with respect to an elapsed time after the heat pump water heater is started.

The present embodiment is different from the thirteenth embodiment in that a hot-time judging means 22 for judging when the compressor is hot and a starting initial valve opening at the start of operation when the compressor is hot are stored. And a sixth storage means 30 provided.

The parts having the same reference numerals as in the thirteenth embodiment have the same configuration, and the description will be omitted.

Next, the operation and operation will be described.

FIG. 35 shows the time after the start of operation on the horizontal axis.
The vertical axis represents the discharge temperature, and shows the relationship of the change in the discharge temperature with respect to the time after the start of operation when the valve opening of the pressure reducing device 3 is kept constant. In the figure, a solid line indicates a case where the compressor 1 is warm when the operation is started, and a dotted line indicates a case where the compressor 1 is cold when the compressor 1 is cold. As can be seen from the figure, the rate of rise of the discharge temperature is higher in the hot state shown by the solid line than in the cold state shown by the dotted line. For this reason, if the startup initial valve opening is the same between hot and cold, the discharge temperature greatly exceeds the target discharge temperature in the case of hot, and as a result, hunting increases. Therefore, the initial valve opening of the hot start is set to be larger than the initial valve opening of the cold start, and the refrigerant circulation amount is increased.

Referring to FIG. 34, when the operation is started, the hot-time judging means 22 judges whether the compressor 1 is hot or the compressor 1 is cold. If it is hot, the sixth storage means 30 that stores the starting initial valve opening degree when hot.
Storage means 2 for storing the dead zone time at the time of start-up
The control means 11 controls the valve opening of the pressure reducing device 3 based on signals from the first storage means 13 storing the target discharge temperature 8 and the target discharge temperature and the discharge temperature detecting means 12.

In the cold state, the fourth storage means 27 for storing the initial valve opening of the cold start, the fifth storage means 28 for storing the dead zone time at the start, and the target discharge temperature. The control means 11 controls the valve opening of the pressure reducing device 3 based on the stored signals from the first storage means 13 and the discharge temperature detection means 12.

As described above, when the operation is started when the compressor 1 is hot, the initial valve opening of the compressor is set to a valve opening larger than the initial valve opening of the cold operation. Since it is set, the required amount of circulating refrigerant can be obtained, so that the efficiency at the time of starting the hot water supply operation is improved, and the hunting of the discharge temperature can be reduced.

(Embodiment 17) FIG. 36 shows Embodiment 1 of the present invention.
FIG. 37 is a configuration diagram showing the heat pump water heater of FIG. 7, and FIG. 37 is an explanatory diagram showing a starting initial valve opening degree when the pressure reducing device is heated with respect to the outside air temperature of the heat pump water heater.

The present embodiment is different from the thirteenth embodiment in that a hot-time judging means 22 for judging when the compressor is hot and a starting initial valve opening degree when the compressor is hot with respect to the outside air temperature are stored. The sixth storage means 30 is provided.

As described in the second embodiment, since the amount of heat absorbed by the evaporator 4 from the atmospheric heat varies greatly depending on the outside air temperature, the required refrigerant circulation amount also changes.

FIG. 37 shows the relationship between the outside air temperature and the initial valve opening during heating with respect to the outside air temperature, with the horizontal axis representing the outside air temperature and the vertical axis representing the opening temperature during startup. In winter when the outside air temperature is low, the amount of heat absorbed from atmospheric heat is small, so the required amount of refrigerant circulating is small. In this case, the startup initial valve opening during heating is reduced. On the other hand, in summer when the outside air temperature is high, the amount of heat absorbed from atmospheric heat is large, so the required amount of refrigerant circulation is large. In this case, the opening degree of the initial valve at the time of heating is increased.

As described above, the required amount of circulating refrigerant can be obtained by changing the initial valve opening of the pressure reducing device 3 in accordance with the outside air temperature at the time of hot operation start-up. And hot water having a predetermined boiling temperature can be obtained immediately after the start of operation.

(Embodiment 18) FIG. 38 shows Embodiment 1 of the present invention.
8 is a configuration diagram showing the heat pump water heater, and FIG. 39 is an explanatory diagram showing a change in the discharge temperature with respect to an elapsed time after the heat pump water heater is started.

This embodiment is different from the fifth embodiment in that a start elapsed time measuring means 31 for measuring an elapsed time from the start of operation and a seventh storage means 32 for storing a predetermined time are provided. It is a configuration.

Note that the portions denoted by the same reference numerals as in the fifth embodiment have the same configuration, and the description will be omitted.

Next, the operation and operation will be described.

FIG. 39 shows the time after the start of operation on the horizontal axis.
The vertical axis represents the discharge temperature, and shows the relationship between the change in the discharge temperature and the time after the start of operation. In the figure, the discharge temperature is substantially constant at time T after the start of operation. Further, when the discharge temperature becomes substantially constant, the other temperatures become substantially constant in the same manner, and it can be determined that a steady operation state has been attained. The time T obtained in advance as described above is stored in the seventh storage means 32 as a predetermined time.

In FIG. 38, when the operation is started, the start elapsed time measuring means 31 measures the elapsed time from the start of the operation. Then, when the elapsed time measured by the activation elapsed time measurement means 31 reaches a predetermined time stored in the seventh storage means 32, the control means 11 determines that the state has changed from the activation state to the steady state.

The following operation and operation are the same as those of the fifth embodiment, and the description is omitted.

(Embodiment 19) FIG. 40 shows Embodiment 1 of the present invention.
FIG. 41 is a configuration diagram showing the heat pump water heater 9 and FIG. 41 is an explanatory diagram showing a change in the discharge temperature with respect to an elapsed time after the heat pump water heater is started.

The present embodiment is different from the fifth embodiment in that the discharge temperature detecting means 12
And a discharge temperature change detecting means 33.

Note that the portions denoted by the same reference numerals as in the fifth embodiment have the same configuration, and description thereof will be omitted. Next, the operation and operation will be described.

FIG. 41 shows the time after the start of operation on the horizontal axis.
The vertical axis represents the discharge temperature, and shows the relationship between the change in the discharge temperature and the time after the start of operation. In the figure, ΔT is a measurement time interval (for example, 5 minutes).
At each T, the discharge temperature detecting means 12 detects the discharge temperature, and the discharge temperature change detecting means 33 detects a change in the discharge temperature during ΔT. As can be seen from the figure, the change Δta in the discharge temperature is large in the initial stage of the startup, but the change Δtb in the discharge temperature is small as the steady state is approached. Now, assuming that the change rate of the discharge temperature Δt (for example, if the change is within 1 degree in 5 minutes, Δt = 0.2 degrees / minute) as the determination value of the steady state, the change rate Δt If it is larger, it is set to the start state, and if it is not more than this change rate Δt, it is set to the steady state.

In FIG. 40, when the operation is started, at every measurement time interval ΔT, the discharge temperature detecting means 12 detects the discharge temperature, and subsequently, the discharge temperature change detecting means 33 detects the change of the discharge temperature. To do. If the rate of change of the discharge temperature detected by the discharge temperature change detecting means 33 becomes equal to or less than the change rate Δt, the control means 11 determines that the state has changed from the start state to the steady state.

The following operation and operation are the same as those of the fifth embodiment, and the description is omitted.

(Embodiment 20) FIG. 42 shows Embodiment 2 of the present invention.
FIG. 43 is a configuration diagram illustrating a heat pump water heater of No. 0, and FIG. 43 is an explanatory diagram illustrating a change in a boiling temperature with respect to an elapsed time after activation of the heat pump water heater.

The present embodiment is different from the fifth embodiment in that a boiling-up temperature detecting means 8 and a boiling-up temperature change detecting means 34 are provided as the starting steady state determining means 20.

Note that the portions denoted by the same reference numerals as those in the fifth embodiment have the same configuration, and description thereof will be omitted.

Next, the operation and operation will be described.

FIG. 43 shows the time after the start of operation on the horizontal axis.
The vertical axis represents the boiling temperature and shows the relationship between the change in the boiling temperature and the time after the start of operation. In the figure, ΔT is a measurement time interval (for example, 5 minutes),
The boiling temperature detecting means 8 detects the boiling temperature at every ΔT, and the boiling temperature change detecting means 34 detects the ΔT
During this time, the change in the boiling temperature is detected. As can be seen from the figure, the change △ Wa in the boiling temperature is large at the initial stage of the startup, but the change △ Wb in the boiling temperature is small as the steady state is approached. Now, as a determination value in a steady state, the rate of change of the boiling temperature １W (for example, if the change is within 1 degree in 5 minutes, △
(W = 0.2 degrees / minute), if the rate of change △ W is larger, the state is set to the starting state, and if the rate of change 以下 W or less, the state is set to the steady state.

In FIG. 42, when the operation is started, the boiling temperature detecting means 8 detects the boiling temperature at every measurement time interval ΔT, and then the boiling temperature change detecting means 3
4 detects a change in the boiling temperature. Then, if the rate of change of the boiling temperature detected by the boiling temperature change detecting means 34 falls below the rate of change ΔW, the control means 11 determines that the operating state has changed to the steady state.

The following operation and operation are the same as those of the fifth embodiment, and the description is omitted.

[0171]

As described above, the heat pump water heater according to claim 1 of the present invention has a refrigerant circulation system in which a compressor, a refrigerant-to-water heat exchanger, a decompression device capable of adjusting the opening degree, and an evaporator are sequentially connected. Circuit, a hot water tank, a circulation pump, a hot water supply circuit in which the refrigerant-to-water heat exchanger is sequentially connected, a discharge temperature detecting means for detecting a discharge temperature of the compressor, and a preset target discharge temperature. Control means for controlling the opening degree of the pressure reducing device, the start discharge temperature control is performed so that the opening degree of the pressure reducing device does not become smaller than the start minimum valve opening degree at the start of operation, so that the discharge temperature rises quickly. Hot water having a predetermined boiling temperature is obtained immediately after the start of operation, and the hot water is stored in the hot water storage tank, so that there is an effect that the hot water does not run out even on a day when the load of hot water supply is large in winter.

Even during the frosting operation in winter, for example, other than when the operation is started, control is performed so that the opening of the pressure reducing device does not become smaller than the minimum valve opening, so that the minimum necessary refrigerant circulation amount can be obtained. Time efficiency is improved.

Further, since the amount of circulating refrigerant is controlled, there is an effect that the amount of circulating refrigerant is not excessively large or small, and the operation efficiency is improved.

Further, since the hunting between the pressure and the temperature at the time of starting the operation is small, the pressure and the temperature do not exceed the upper limits of the normal pressure and the normal temperature, and there is an effect that the durability of the compressor is improved.

[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 an explanatory diagram showing the relationship between the discharge temperature and the valve opening with respect to the time after the start of operation when the valve opening of the heat pump water heater is not limited.

FIG. 3 is an explanatory diagram showing the relationship between the discharge temperature and the valve opening with respect to the time after the start of operation when a lower limit (starting minimum valve opening) is provided for the valve opening of the heat pump water heater.

FIG. 4 is an explanatory diagram showing a change in a boiling temperature with respect to a time after starting operation of the heat pump water heater.

FIG. 5 is an explanatory diagram showing changes in valve opening, discharge temperature, and hot water heating capacity with respect to time after frost formation of the heat pump water heater.

FIG. 6 is a configuration diagram illustrating a heat pump water heater according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram showing the minimum valve opening of the pressure reducing device with respect to the outside air temperature of the heat pump water heater.

FIG. 8 is a configuration diagram illustrating a heat pump water heater according to a third embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a feed water temperature with respect to an outside air temperature of the heat pump water heater.

FIG. 10 is an explanatory diagram showing a minimum valve opening of the pressure reducing device with respect to a feed water temperature of the heat pump water heater.

FIG. 11 is a configuration diagram illustrating a heat pump water heater according to a fourth embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a change in temperature detected by water supply temperature detection means with respect to the presence or absence of hot water from the heat pump water heater.

FIG. 13 is a configuration diagram illustrating a heat pump water heater according to a fifth embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a change in discharge temperature with respect to an elapsed time after the start of the heat pump water heater.

FIG. 15 is an explanatory diagram showing a change in discharge pressure with respect to the opening degree of the pressure reducing device in a steady state of the heat pump water heater.

FIG. 16 is a configuration diagram showing a heat pump water heater according to Embodiment 6 of the present invention.

FIG. 17 is an explanatory diagram showing a change in discharge pressure at different power supply frequencies with respect to the opening degree of the pressure reducing device in a steady state of the heat pump water heater.

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

FIG. 19 is an explanatory diagram showing a change in discharge temperature with respect to an elapsed time after the start of the heat pump water heater.

FIG. 20 is a configuration diagram illustrating a heat pump water heater according to an eighth embodiment of the present invention.

FIG. 21 is a configuration diagram showing a heat pump water heater according to a ninth embodiment of the present invention.

FIG. 22 is a configuration diagram showing a heat pump water heater according to a seventh embodiment of the present invention.

FIG. 23 is an explanatory diagram showing a change in discharge temperature with respect to an elapsed time after the start of the heat pump water heater.

FIG. 24 is a configuration diagram showing a heat pump water heater according to Embodiment 11 of the present invention.

FIG. 25 is an explanatory diagram showing the minimum opening of a pressure reducing device (minimum opening of a hot start valve) with respect to the outside air temperature when the heat pump water heater is hot.

FIG. 26 is a configuration diagram showing a heat pump water heater according to Embodiment 12 of the present invention.

FIG. 27 is an explanatory diagram showing a minimum valve opening of the pressure reducing device when the pressure reducing device is heated when the temperature of the heat pump water supply device is increased.

FIG. 28 is a configuration diagram showing a heat pump water heater according to Embodiment 13 of the present invention.

FIG. 29 is an explanatory diagram showing a relationship between a discharge temperature and a valve opening degree with respect to a time after starting operation of the heat pump water heater.

FIG. 30 is a configuration diagram showing a heat pump water heater according to Embodiment 14 of the present invention.

FIG. 31 is an explanatory diagram showing the initial valve opening of the pressure reducing device at the start of operation with respect to the outside air temperature of the heat pump water heater.

FIG. 32 is a configuration diagram illustrating a heat pump water heater according to Embodiment 15 of the present invention.

FIG. 33 is an explanatory diagram showing a dead zone time at the time of startup without performing discharge temperature control on the outside air temperature of the heat pump water heater.

FIG. 34 is a configuration diagram showing a heat pump water heater according to Embodiment 16 of the present invention.

FIG. 35 is an explanatory diagram showing a change in discharge temperature with respect to an elapsed time after activation of the heat pump water heater.

FIG. 36 is a configuration diagram showing a heat pump water heater of embodiment 17 of the present invention.

FIG. 37 is an explanatory diagram showing a starting initial valve opening degree when the pressure reducing device is heated with respect to the outside air temperature of the heat pump water heater.

FIG. 38 is a configuration diagram showing a heat pump water heater according to Embodiment 18 of the present invention.

FIG. 39 is an explanatory diagram showing a change in discharge temperature with respect to an elapsed time after the start of the heat pump water heater.

FIG. 40 is a configuration diagram showing a heat pump water heater of a nineteenth embodiment of the present invention.

FIG. 41 is an explanatory diagram showing a change in discharge temperature with respect to an elapsed time after the start of the heat pump water heater.

FIG. 42 is a configuration diagram showing a heat pump water heater according to a twentieth embodiment of the present invention.

FIG. 43 is an explanatory diagram showing a change in a boiling temperature with respect to an elapsed time after activation of the heat pump water heater.

FIG. 44 is a configuration diagram showing a heat pump water heater in the first conventional example.

FIG. 45 is a configuration diagram showing a heat pump water heater in a second conventional example.

[Description of Signs] 1 Compressor 2 Refrigerant-to-water heat exchanger 3 Decompression device 4 Evaporator 5 Hot water storage tank 6 Circulation pump 11 Control means 12 Discharge temperature detection means

Claims (20)

[Claims] 1. A refrigerant circuit in which a compressor, a refrigerant-to-water heat exchanger, a decompression device capable of adjusting an opening degree, and an evaporator are sequentially connected.
A hot water supply circuit in which a hot water storage tank, a circulation pump, and the refrigerant-to-water heat exchanger are sequentially connected, discharge temperature detecting means for detecting a discharge temperature of the compressor, and the pressure reducing device so as to reach a preset target discharge temperature Control means for controlling the opening of the
A heat pump water heater, wherein a minimum valve opening is provided for the opening of the pressure reducing device. 2. The heat pump water heater according to claim 1, wherein the minimum valve opening of the pressure reducing device varies depending on the outside air temperature obtained by a signal from the outside air temperature detecting means. 3. The heat pump water heater according to claim 1, wherein the minimum valve opening of the pressure reducing device varies depending on the feed water temperature obtained by a signal from the feed water temperature detecting means. 4. The heat pump water heater according to claim 3, wherein the hot water temperature detecting means detects the hot water temperature after the hot water detecting means detects hot water. 5. The system according to claim 1, wherein the minimum valve opening of the pressure reducing device is changed between the start of operation and the steady state by a signal from the start / steady state determination means for judging the start and steady state of the operation. Heat pump water heater. 6. The heat pump water heater according to claim 1, wherein the minimum valve opening of the pressure reducing device varies depending on the power supply frequency. 7. When the operation is started when the hot time judging means for judging whether or not the compressor is warm detects the hot time,
2. The heat pump water heater according to claim 1, wherein the minimum opening of the pressure reducing device is increased. 8. The heat pump water heater according to claim 7, wherein a compressor temperature detecting means is used as the hot time judging means. 9. The heat pump water heater according to claim 7, wherein a first time measuring means for calculating an elapsed time from a previous stop of operation is used as the hot time judging means. 10. The heat pump water heater according to claim 7, wherein a second time measuring means for calculating an elapsed time after the start of operation and a discharge temperature detecting means are used as the hot time judging means. 11. The heat pump water heater according to claim 7, wherein the minimum opening of the decompression device when the temperature is hot varies depending on the outside air temperature obtained by a signal from the outside air temperature detecting means. 12. The heat pump water heater according to claim 7, wherein the minimum opening degree of the decompression device at the time of heating is different depending on the feed water temperature obtained by a signal from the feed water temperature detecting means. 13. A heat pump hot water supply according to claim 1, wherein a dead zone time is provided for fixing the opening of the pressure reducing device to an opening of the initial valve which is equal to or greater than the minimum valve opening when the operation is started. Machine. 14. The heat pump water heater according to claim 13, wherein the opening degree of the starting valve differs depending on the outside air temperature obtained by a signal from the outside air temperature detecting means. 15. The heat pump water heater according to claim 13, wherein the dead zone time varies depending on the outside air temperature obtained by a signal from the outside air temperature detecting means. 16. The heat pump water heater according to claim 13, wherein the initial opening of the valve during startup is increased when it is hot. 17. The heat pump water heater according to claim 13, wherein the initial opening of the valve at the time of heating is different depending on the outside air temperature obtained by a signal from the outside air temperature detecting means. 18. The heat pump water heater according to claim 5, wherein a starting elapsed time measuring means for measuring an elapsed time from the start of the operation is used as the starting steady state determining means. 19. The heat pump water heater according to claim 5, wherein a discharge temperature detecting means and a discharge temperature change detecting means are used as the steady start determination means. 20. The heat pump water heater according to claim 5, wherein a boiling temperature detecting means and a boiling temperature change detecting means are used as the starting steady state determining means.