JP3856028B2 - Heat pump water heater - Google Patents

Description

  The present invention relates to a hot water storage type heat pump water heater.

  As shown in FIG. 28, a conventional heat pump water heater of this type includes a refrigerant circulation circuit including a compressor 1, a refrigerant-to-water heat exchanger 2, a decompression device 3, an evaporator 4, a hot water tank 5, and a circulation pump 6. The high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 1 flows into the refrigerant-to-water heat exchanger 2 in the form of a hot water supply circuit connected to the refrigerant-to-water heat exchanger 2 and the auxiliary heater 7. The water sent from the circulation pump 6 is heated.

  The refrigerant that exchanges heat with water is decompressed by the decompression device 3 and flows into the evaporator 4, where it absorbs atmospheric heat to evaporate and returns to the compressor 1. On the other hand, the hot water heated in the refrigerant-to-water heat exchanger 2 flows into the upper part of the hot water storage tank 5 and is gradually stored from above.

When the inlet water temperature of the refrigerant-to-water heat exchanger 2 reaches a set value, the feed water temperature detecting means 8 detects it, stops the heat pump operation by the compressor 1, and switches to the independent operation of the auxiliary heater 7. (See, for example, Patent Document 1).
JP 60-164157 A

  In the conventional heat pump water heater shown in FIG. 28, a capillary tube or a temperature type expansion valve is used as the decompression device 3. When a capillary tube is used as the decompression device 3, the specification of the capillary tube is generally designed based on the summer temperature conditions in which the refrigerant circulation amount is large.

  Therefore, since the refrigerant flows more than necessary at the start of operation particularly in winter other than the summer, the temperature rise of the compressor 1 is slow, and the hot water at the outlet of the refrigerant-to-water heat exchanger 2 flows into the upper part of the hot water storage tank 5 at a low temperature. The hot water is stored. Therefore, there is a problem that the hot water in the hot water tank 5 is mixed with the hot water in the hot water tank 5 to lower the hot water temperature in the hot water tank 5 and sometimes the hot water runs out.

  Further, even during steady operation after the temperature of the compressor 1 has risen, similarly, since more refrigerant than necessary circulates in the refrigerant circulation circuit, there has been a problem that the efficiency of operation is deteriorated. Further, in some cases, the liquid refrigerant is sucked into the compressor 1, and as a result, there is a problem that liquid compression occurs and the durability of the compressor 1 is deteriorated.

  On the other hand, when a temperature type expansion valve is used as the pressure reducing device 3, generally, the temperature type expansion valve as the pressure reducing device 3 is set so that the refrigerant at the outlet of the evaporator 4 is in a superheated gas state with a certain degree of superheat. Design the specifications.

  However, since the distribution of the refrigerant in the refrigerant circuit is not stable at the start of operation, the discharge pressure and discharge temperature of the compressor 1 may hunt (up and down fluctuations) and exceed the upper limit discharge pressure and upper limit discharge temperature. It had the subject that durability of worsened.

  In addition, even during steady-state operation, the discharge pressure rises when the temperature is higher than the designed outside air temperature, and the discharge temperature rises in winter when the outside air temperature is low. Was.

  An object of the present invention is to realize an efficient hot water supply heating operation with less hot water shortage.

In order to solve the above-mentioned conventional problems, a compressor, a refrigerant-to-water heat exchanger, a decompression device that controls the flow rate of the refrigerant, a refrigerant circulation circuit provided with an evaporator, a hot water tank, a circulation pump, the refrigerant-to-water heat A hot water supply circuit provided with an exchanger, discharge temperature detection means for detecting the discharge temperature of the compressor, and water supply temperature detection means for detecting the water-side inlet water temperature of the refrigerant-to-water heat exchanger. When the machine is started , the valve opening of the pressure reducing device is set to a preset initial valve opening in accordance with a signal from the feed water temperature detecting means .

  As a result, the valve opening degree of the pressure reducing device is controlled so as to reach the target discharge temperature, so that an appropriate refrigerant is always circulated through the refrigerant circuit, and both the pressure and temperature are stabilized.

The heat pump water heater of the present invention controls an abnormal temperature rise due to hunting of the compressor discharge temperature or discharge pressure by controlling the valve opening of the pressure reducing device to a preset initial valve opening when the compressor is started. In addition, there is no abnormal pressure rise and durability is high, and the temperature of the compressor rises quickly, and the hot water at the outlet of the refrigerant-to-water heat exchanger immediately becomes hot, so that the possibility of running out of hot water can be reduced.

The first invention is provided with a compressor, a refrigerant-to-water heat exchanger, a decompression device for controlling the flow rate of the refrigerant, a refrigerant circulation circuit provided with an evaporator, a hot water tank, a circulation pump, and the refrigerant-to-water heat exchanger. A hot water supply circuit, discharge temperature detection means for detecting the discharge temperature of the compressor, and water supply temperature detection means for detecting the water-side inlet water temperature of the refrigerant-to-water heat exchanger, when the compressor is started The valve opening of the pressure reducing device is set to a preset initial valve opening in accordance with a signal from the feed water temperature detecting means .

  Therefore, by providing a control means for setting the valve opening of the pressure reducing device to a preset initial valve opening at the time of starting the compressor, proper refrigerant circulates in the refrigerant circuit even at the start of operation. The compressor discharge temperature and discharge pressure hunting does not cause an abnormal temperature rise or abnormal pressure rise, and the durability is high. The compressor temperature rises quickly, and the hot water at the outlet of the refrigerant-to-water heat exchanger immediately becomes hot. Therefore, the possibility of running out of hot water can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
Hereinafter, an embodiment will be described with reference to FIGS. In addition, the same code | symbol is used for the same component as FIG. 28 demonstrated by the prior art example, and description is abbreviate | omitted.

  In FIG. 1, the rotation speed control means 10 controls the rotation speed of the circulation pump 6 by a signal from the boiling temperature detection means 9 provided at the water-side outlet of the refrigerant-to-water heat exchanger 2, and the refrigerant-to-water heat The outlet water temperature (boiling temperature) of the exchanger 2 is boiled so as to be substantially constant. Further, the control unit 11 controls the decompression device 3 with a signal from the target discharge temperature storage unit 12 that stores the target discharge temperature and the discharge temperature detection unit 13 that detects the discharge temperature of the compressor 1. The decompression device 3 includes an electric expansion valve (not shown).

  Next, the operation and action will be described. FIG. 2 shows the valve opening of the pressure reducing device 3 on the horizontal axis and the discharge temperature, discharge pressure, and efficiency on the vertical axis, and the discharge temperature and discharge pressure with respect to the valve opening of the pressure reducing device 3 at a certain outside air temperature. It shows the relationship of efficiency. As can be seen from the figure, the efficiency has a maximum value with respect to the valve opening degree of the decompression device 3. In the figure, the alternate long and short dash line is the upper limit discharge temperature during normal use of the compressor (normal maximum discharge temperature), and the alternate long and two short dashes line is the upper limit discharge pressure during normal use of the compressor (normal maximum discharge pressure). .

  Here, the discharge temperature with respect to the valve opening X of the pressure reducing device 3 at which the efficiency is maximized is defined as a target discharge temperature Y. This target discharge temperature Y is stored in advance in the target discharge temperature storage means 12.

  That is, when the hot water supply operation starts and the compressor 1 is started, the control unit 11 detects the discharge temperature by the signal from the discharge temperature detection unit 13. If the current discharge temperature is higher than the target discharge temperature based on the information from the target discharge temperature storage unit 12 storing the target discharge temperature, the control unit 11 increases (opens) the valve opening degree of the decompression device 3. ) To control.

  Conversely, if the current discharge temperature is lower than the target discharge temperature, the control means 11 controls the valve opening degree of the pressure reducing device 3 to be reduced (closed).

  As described above, if the discharge temperature control by the control means 11 is performed every certain time, an efficient hot water supply operation is always possible. In addition, since the proper refrigerant circulates in the refrigerant circuit at all times to control the valve opening of the decompression device 3 so as to reach the target discharge temperature, there is no abnormal temperature rise or abnormal pressure rise, and durability can be improved. it can.

(Embodiment 2)
The second embodiment will be described with reference to FIGS. The second embodiment is different from the first embodiment in that the initial valve opening degree storage means 14 that stores the valve opening degree of the pressure reducing device 3 at the time of starting operation is provided. In addition, the part of the same code | symbol as Embodiment 1 has the same structure, and description is abbreviate | omitted.

  Next, the operation and action will be described. In FIG. 3, when the operation is started, the control means 11 uses the signal from the initial valve opening degree storage means 14 that stores the valve opening degree (initial valve opening degree) of the pressure reducing apparatus 3 at the time of activation. After the opening is set to the initial valve opening, the hot water supply heating operation is started.

  FIG. 4 shows the change in the discharge temperature with respect to the operation time, with the operation time on the horizontal axis and the discharge temperature on the vertical axis. In the figure, Tg is a target discharge temperature. Td0 is the control start discharge temperature. Until the discharge temperature reaches this temperature, the valve opening of the pressure reducing device 3 is made constant at the initial valve opening, and if the discharge temperature becomes equal to or higher than the control start discharge temperature Td0, the operation is performed. As described in Example 1, the discharge temperature control operation is performed. That is, the control unit 11 detects the discharge temperature based on a signal from the discharge temperature detection unit 13.

  If the current discharge temperature is higher than the target discharge temperature based on the information from the target discharge temperature storage unit 12 storing the target discharge temperature, the control unit 11 increases (opens) the valve opening degree of the decompression device 3. ) To control. Conversely, if the current discharge temperature is lower than the target discharge temperature, the control means 11 controls the valve opening degree of the pressure reducing device 3 to be reduced (closed).

  Now, in FIG. 4, the valve opening degree of the pressure reducing device 3 when the discharge temperature reaches the target discharge temperature and becomes a steady state is defined as the ultimate valve opening degree. In the figure, the solid line A shows the change in the discharge temperature when the valve opening of the pressure reducing device 3 is operated at the ultimate valve opening from the start of operation.

  If the valve is operated with a valve opening smaller (closed) than the ultimate valve opening, it becomes like the one-dot chain line B, and the discharge temperature hunts (up and down), and in some cases exceeds the upper limit discharge temperature. There is also. Conversely, when the engine is operated with a valve opening that is larger (open) than this ultimate valve opening, it becomes as shown by dotted line C, and the discharge temperature rises slowly, and it takes time to reach the target discharge temperature.

  Therefore, the valve opening Z that is the ultimate valve opening is obtained in advance and stored in the initial valve opening storage means 14. At the start of the hot water supply operation, the control means 11 obtains the initial valve opening degree (valve opening degree Z) of the pressure reducing device 3 from the signal from the initial valve opening degree storage means 14. And after the control means 11 sets the valve opening degree of the decompression device 3 to the valve opening degree Z, the hot water supply heating operation is started.

  As described above, by setting the valve opening of the pressure reducing device 3 to a preset initial valve opening at the start of operation, an appropriate refrigerant circulates in the refrigerant circuit. No abnormal temperature rise or abnormal pressure rise due to pressure hunting, durability is high, discharge temperature rise of the compressor 1 is fast, and hot water at the outlet of the refrigerant-to-water heat exchanger 2 immediately becomes hot. The possibility of this can be reduced.

(Embodiment 3)
5 and 6, the difference from the second embodiment is provided with a hot and cold detection means 15 for detecting a hot start when the compressor 1 is warm and a cold start when the compressor 1 is cold. It is a configuration. Here, the discharge temperature detection means 13 is used as the hot / cold detection means 15. In addition, the part of the same code | symbol as Embodiment 2 has the same structure, and abbreviate | omits description.

  Next, the operation and action will be described. FIG. 6 shows the change of the discharge temperature with respect to the operation time, with the operation time on the horizontal axis and the discharge temperature on the vertical axis. In the figure, Tg is a target discharge temperature. Further, Td0 is a control start discharge temperature. Until the discharge temperature reaches this temperature, the valve opening of the pressure reducing device 3 is made constant at the initial valve opening. If the discharge temperature becomes equal to or higher than the control start discharge temperature Td0, the operation is performed. As described in the first embodiment, the discharge temperature control operation is performed.

  The change in the discharge temperature shown by the solid line in the figure is the case of the start-up when the compressor 1 is warm at the start of operation, and the change in the discharge temperature shown by the alternate long and short dash line is the cool of the compressor 1 at the start of the operation. This is the case of cold start. As can be seen from the figure, in the case of start-up during heat, the rise is fast and the steady state is immediately reached.

  On the other hand, in the case of cold start, the rise is slow and it takes time to reach a steady state. The valve opening degree of the decompression device 3 (the valve opening degree Z described in the second embodiment) when the steady state is reached is the same in both the case of starting in the hot state and the case of starting in the cold state. In order to speed up the start of the cold start, the initial valve opening of the decompression device 3 is set smaller in the cold start than in the hot start. Then, as shown by the dotted line (improvement during cold) in the figure, the discharge temperature rises relatively quickly.

  In FIG. 6, Tjd is the hot / cold determination discharge temperature for determining the distinction between the hot start and the cold start, and the distinction between the hot start and the cold start is made after a predetermined waiting time t after the start of operation. It shall be determined. That is, at the start of the hot water supply operation, the control means 11 obtains the initial valve opening degree (valve opening degree Z) of the pressure reducing device 3 from the signal from the initial valve opening degree storage means 14.

  And after the control means 11 sets the valve opening degree of the decompression device 3 to the valve opening degree Z, the hot water supply heating operation is started. Then, after the start-up and a predetermined standby time t, if the discharge temperature obtained from the signal from the discharge temperature detecting means 13 is a temperature (point A) equal to or higher than the hot-time determination discharge temperature Tjd, it is determined that the start-up is hot. If the temperature is lower than the hot-time cold determination discharge temperature Tjd (point B), it is determined that the engine is cold-started. As a result of the determination, in the case of start-up during heat, the operation is continued with the valve opening (valve opening Z) as it is.

  On the other hand, in the case of cold start, the control means 11 sets the valve opening of the pressure reducing device 3 to a valve opening (valve opening Zm) smaller than the valve opening Z and continues the operation. The valve opening Zm is obtained in advance in a range where there is no large overshoot of the discharge temperature.

  In both the case of the start at the time of heating and the case of the start at the cold time, if the discharge temperature becomes equal to or higher than the control start discharge temperature Td0, the discharge temperature control operation is performed as described in the first embodiment. That is, the control unit 11 detects the discharge temperature based on a signal from the discharge temperature detection unit 13. If the current discharge temperature is higher than the target discharge temperature based on the information from the target discharge temperature storage unit 12 storing the target discharge temperature, the control unit 11 increases (opens) the valve opening degree of the decompression device 3. ) To control. Conversely, if the current discharge temperature is lower than the target discharge temperature, the control means 11 controls the valve opening degree of the pressure reducing device 3 to be reduced (closed).

  As described above, since the valve opening degree of the decompression device 3 is set according to the temperature at the time of starting the compressor 1, an appropriate refrigerant circulates in the refrigerant circuit even at the time of starting the operation. The temperature rise of 1 is fast and the hot water at the outlet of the refrigerant-to-water heat exchanger 2 immediately becomes high temperature, so that the possibility of hot water shortage can be reduced.

(Embodiment 4)
7 and 8, the difference from the third embodiment is that the discharge temperature detection means 13 and the outside air temperature detection means 16 are used as the hot / cold detection means 15. In addition, the part of the same code | symbol as Embodiment 3 has the same structure, and description is abbreviate | omitted.

  Next, the operation and action will be described. In FIG. 8, the horizontal axis represents the temperature of the compressor 1 after operation stop, and the vertical axis represents the temperature of the pipe provided with the discharge temperature detection means 13 to detect the discharge temperature relative to the temperature of the compressor 1 after operation stop. The relationship of the temperature change of the piping which attached the means 13 is shown.

  Now, the discharge temperature detecting means 13 for detecting the discharge temperature is provided in a pipe connected to the discharge port of the compressor 1. Since the refrigerant circulates during operation, the temperature of the compressor 1 and the temperature of the pipe part to which the discharge temperature detecting means 13 is attached are substantially equal, but when the operation is stopped, the temperature of the compressor 1 and the discharge temperature are detected. There is a difference from the temperature of the pipe part to which the means 13 is attached.

  That is, the compressor 1 has a larger heat capacity than the pipe to which the discharge temperature detecting means 13 is attached, and the compressor 1 is usually covered with a heat insulating material for soundproofing. For this reason, the speed of the temperature drop of the compressor 1 is smaller than the speed of the temperature drop of the pipe to which the discharge temperature detecting means 13 is attached.

  Further, the speed of temperature decrease also depends on the outside air temperature. Of course, the lower the outside air temperature, the greater the rate of temperature decrease.

  In the figure, Tg is a target discharge temperature, and Tj is a hot / cold determination compressor temperature for determining a distinction between the hot start and the cold start. That is, when the operation is started, if the temperature of the compressor 1 is equal to or higher than Tj, it is a hot start, and if it is lower than Tj, it is a cold start.

  Further, the solid line shows the relationship between the temperature of the compressor 1 after the operation stop in summer (for example, outside air temperature 35 ° C.) and the temperature of the pipe to which the discharge temperature detecting means 13 is attached. Similarly, an alternate long and short dash line and a dotted line show the relationship in the intermediate period (for example, outside air temperature 20 ° C.) and winter (for example, outside air temperature 5 ° C.), respectively. In the above-described relationship in summer, intermediate period, and winter, the temperatures of the pipes to which the discharge temperature detecting means 13 is attached when the temperature of the compressor 1 after the operation stops becomes the hot / cold determination compressor temperature Tj are T1 respectively. , T2, and T3.

  If T1, T2, and T3 are obtained in advance for this outside air temperature (for example, 35 ° C., 20 ° C., 5 ° C.), the start-up or the cold start is performed according to the signal from the discharge temperature detecting means 13. It is possible to determine whether to start up.

  As described above, even if the outside air temperature changes, the valve opening degree of the pressure reducing device 3 corresponding to the initial temperature of the compressor 1 is set with respect to the outside air temperature. Since the temperature of the compressor rises quickly even when it is cold, and the hot water at the outlet of the refrigerant-to-water heat exchanger quickly becomes hot, the possibility of running out of hot water can be reduced.

(Embodiment 5)
In FIG. 9, the difference from the third embodiment is that the compressor temperature detecting means 17 is used as the hot / cold detecting means 15. In addition, the part of the same code | symbol as Embodiment 3 has the same structure, and description is abbreviate | omitted.

Next, the operation and action will be described. As described in the fourth embodiment, when the temperature of the compressor 1 for determining the distinction between the hot start and the cold start is the hot cold determination compressor temperature Tj, the temperature of the compressor 1 at the start of operation If it is equal to or higher than Tj, it is a hot start, and if it is smaller than Tj, it is a cold start.

  That is, at the start of the hot water supply operation, the control means 11 obtains the temperature of the compressor 1 with a signal from the compressor temperature detection means 17. If the obtained temperature is equal to or higher than the above-described hot / cold determination compressor temperature Tj, the control means 11 determines that the engine is activated when it is hot, and sets the valve opening of the decompression device 3 to the valve opening Z. After that, the hot water heating operation is started. On the contrary, if the obtained temperature is lower than the above-described hot / cold determination compressor temperature Tj, the control means 11 determines that it is cold start, and the valve opening of the pressure reducing device 3 is smaller than the valve opening Z. After setting to (valve opening Zm), hot water supply heating operation is started.

  As described above, since the temperature of the compressor 1 is directly detected, there is no waiting time for determining when the temperature is cold and the valve opening of the pressure reducing device 3 can be set to an optimum value simultaneously with the start of operation. Can be improved.

(Embodiment 6)
FIG. 10 is a configuration diagram of a heat pump water heater according to Embodiment 6 of the present invention, and FIG. 11 is an explanatory diagram showing the temperature of a pipe provided with a discharge temperature detecting means 13 with respect to the time after the operation of the heat pump water heater is stopped. 12 is explanatory drawing which shows the determination time at the time of cold at the time with respect to the external temperature of the heat pump water heater.

  In the present embodiment, the difference from the third embodiment is that, as the hot and cold detection means 15, a time measurement means 18 for measuring the elapsed time from the previous operation stop, and an outside air temperature detection means 16 for detecting the outside air temperature. It is that it is the structure using. In addition, the part of the same code | symbol as Embodiment 3 has the same structure, and description is abbreviate | omitted.

  Next, the operation and action will be described. In FIG. 11, the horizontal axis represents the time after the operation stop, the vertical axis represents the temperature of the pipe with the discharge temperature detection means 13, and the pipe with the discharge temperature detection means 13 with respect to the time after the operation stop. This shows the relationship of temperature change.

  In the figure, Tg is a target discharge temperature, and Tjh is a hot / cold determination discharge pipe temperature for determining a distinction between a hot start and a cold start. Now, the discharge temperature detecting means 13 for detecting the discharge temperature is provided in a pipe connected to the discharge port of the compressor 1.

  When the operation is stopped, the temperature of the compressor 1 is lowered and the temperature of the pipe to which the discharge temperature detecting means 13 is attached is also lowered. Further, the speed of temperature decrease also depends on the outside air temperature. Of course, the lower the outside air temperature, the greater the rate of temperature decrease.

  In the figure, the solid line shows the change in the temperature of the pipe provided with the discharge temperature detecting means 13 with respect to the time after operation stop in summer (for example, outside air temperature 35 ° C.). Similarly, the alternate long and short dash line and the dotted line indicate changes in the temperature of the pipe to which the discharge temperature detecting means 13 is attached in the intermediate period (for example, outside air temperature 20 ° C.) and winter (for example, outside air temperature 5 ° C.).

  Further, if the temperature of the pipe to which the discharge temperature detecting means 13 is attached is equal to or higher than the hot / cold determination discharge pipe temperature Tjh for determining the distinction between the hot start and the cold start, the hot start is performed. If it is lower than the cold determination discharge pipe temperature Tjh, it is cold start. In the summer, the middle period, and winter, the time after the operation stop when the temperature of the pipe to which the discharge temperature detecting means 13 is attached becomes equal to the hot and cold determination discharge pipe temperature Tjh is t1, t2, and t3, respectively. This time is referred to as a hot / cold determination time.

In other words, when the operation is started, if the time since the previous operation stop is equal to or less than the hot cold determination time, it is hot start, and if it is longer than the hot cold determination time, it is cold start. Become.

  In FIG. 12, the horizontal axis represents the outside air temperature, and the vertical axis represents the hot / cold determination time. The relationship between the outdoor air temperature and the hot / cold determination time is shown. In the figure, the part shown by the solid line is the start-up when it is hot, and the upper part is the start-up when it is cold. By obtaining the relationship shown in FIG. 12 in advance, it is possible to determine whether to start in the hot state or in the cold state based on the signal from the time measuring unit 18 and the outside air temperature detecting unit 16.

  That is, when the hot water supply operation is started, the control unit 11 obtains an elapsed time from the previous operation stop by a signal from the time measurement unit 18 and further obtains an outside air temperature by a signal from the outside air temperature detection unit 16. If the elapsed time from the previous shutdown is equal to or less than the above-described hot / cold determination time at the determined outside air temperature, the control means 11 determines that the engine is hot and the valve opening of the decompression device 3 is determined. After the valve opening Z is set, the hot water heating operation is started.

  On the other hand, if the elapsed time from the previous shutdown is longer than the above-mentioned hot / cold determination time, the control means 11 determines that the engine is cold and the valve opening of the pressure reducing device 3 is smaller than the valve opening Z. After the temperature (valve opening Zm) is set, the hot water supply heating operation is started.

  As described above, it is possible to make a judgment at the same time as the start of operation because the elapsed time since the previous shutdown and the outside air temperature are judged. be able to.

(Embodiment 7)
13 and 14, the difference from the second embodiment is that a control means 11 for determining the initial valve opening degree of the decompression device 3 in accordance with a signal from the outside air temperature detection means 16 is provided. In addition, the part of the same code | symbol as Embodiment 2 has the same structure, and abbreviate | omits description.

  Next, the operation and action will be described. In FIG. 14, the horizontal axis represents the outside air temperature, and the vertical axis represents the refrigerant circulation amount and the valve opening degree of the decompression device 3, and shows the change in the refrigerant circulation amount and the valve opening degree of the decompression device 3 with respect to the outside air temperature. It is.

  In general, as the outside air temperature increases, the energy that the evaporator 4 obtains from atmospheric heat increases. Accordingly, as shown in the figure, since the refrigerant circulation amount increases, in order to make the discharge temperature and discharge pressure of the compressor 1 equal to or lower than the upper limit discharge temperature and the upper limit discharge pressure, the valve opening of the decompression device 3 Needs to be enlarged (opened).

  Therefore, the valve opening Z, which is the reaching valve opening described in the second embodiment, is obtained in advance with respect to the outside air temperature and stored in the initial valve opening storage unit 14. At the start of the hot water supply operation, the control means 11 obtains the initial valve opening (valve opening Z) of the pressure reducing device 3 from the signal from the outside air temperature detecting means 16 and the signal from the initial valve opening storage means 14. And after the control means 11 sets the valve opening degree of the decompression device 3 to the valve opening degree Z, the hot water supply heating operation is started.

  As described above, since the initial valve opening degree of the decompression device 3 is set with respect to the outside air temperature, even if the outside air temperature changes, an appropriate refrigerant circulates at the start of operation. There is no abnormal temperature rise or abnormal pressure rise due to pressure hunting, and durability is high. The temperature rise of the compressor 1 is fast, and the hot water at the outlet of the refrigerant-to-water heat exchanger 2 immediately becomes high temperature. The possibility can be reduced.

(Embodiment 8)
FIG. 15 is a configuration diagram of the heat pump water heater according to the eighth embodiment of the present invention, FIG. 16 is an explanatory diagram showing the temperature of hot water in the hot water storage tank with respect to the height direction of the hot water storage tank, and FIG. FIG. 18 is an explanatory diagram showing the valve opening degree of the decompression device with respect to the feed water temperature of the heat pump water heater.

  In this example, the difference from the second embodiment is that the initial valve opening is set according to the signal from the feed water temperature detecting means 8 that detects the feed water temperature that is the water side inlet water temperature of the refrigerant-to-water heat exchanger 2. In other words, the control means 11 for determination is provided. In addition, the part of the same code | symbol as Embodiment 2 has the same structure, and abbreviate | omits description.

  Next, the operation and action will be described. FIG. 16 shows the temperature distribution of hot water in the hot water tank with the horizontal axis representing the temperature of the hot water in the hot water tank 5 and the vertical axis representing the height of the hot water tank 5. As described above, the rotation speed control means 10 controls the rotation speed of the circulation pump 6 by the signal from the boiling temperature detection means 9 provided at the water-side outlet of the refrigerant-to-water heat exchanger 2, and the refrigerant-to-water The outlet water temperature (boiling temperature) of the heat exchanger 2 is boiled so as to be substantially constant.

  However, as the boiling operation time elapses, a mixed layer in which high-temperature hot water and low-temperature water are mixed is formed at a portion where the hot water and low-temperature water are in contact with each other in the hot water storage tank 5, and the layer gradually expands. In the figure, the above-mentioned mixed layer is generated by heat conduction and convection between hot and cold hot water, and heat is transferred from the hot water to the cold hot water, and the temperature of the hot water drops at the boundary. Low temperature hot water rises.

  Accordingly, when the boiling operation is nearly completed, the water temperature flowing into the refrigerant-to-water heat exchanger 2 increases rapidly with time. In FIG. 17, the horizontal axis represents the feed water temperature, which is the water-side inlet water temperature of the refrigerant-to-water heat exchanger 2, the vertical axis represents the discharge pressure, and the valve opening of the decompression device 3 is used as a parameter to determine the discharge pressure relative to the feed water temperature. This shows the relationship.

  As can be seen from the figure, the higher the feed water temperature, the higher the discharge pressure. However, for the same feed water temperature, the greater the valve opening of the decompression device 3, the lower the discharge pressure. Now, assuming that the design discharge pressure is Ps, the feed water temperatures at which the design discharge pressure Ps is set are Tw1, Tw2, and Tw3 for the valve opening degree of the decompression device 3 being large, medium, and small, respectively. Further, FIG. 18 shows this relationship with respect to the feed water temperature and the valve opening degree of the decompression device 3. That is, the horizontal axis represents the feed water temperature, which is the water-side inlet water temperature of the refrigerant-to-water heat exchanger 2, and the vertical axis represents the valve opening of the decompression device 3, and the relationship between the valve opening of the decompression device 3 and the feed water temperature. Is shown.

  Therefore, the valve opening Z, which is the ultimate valve opening described in the embodiment, is obtained in advance with respect to the feed water temperature, and is stored in the initial valve opening storage means 14. At the start of the hot water supply operation, the control means 11 obtains the initial valve opening (valve opening Z) of the pressure reducing device 3 from the signal from the feed water temperature detecting means 8 and the signal from the initial valve opening storage means 14. And after the control means 11 sets the valve opening degree of the decompression device 3 to the valve opening degree Z, the hot water supply heating operation is started.

  As described above, since the initial valve opening is set in accordance with the feed water temperature, the hot water in the hot water / mixed layer region of the hot water tank 5 can also be boiled, and therefore the hot water volume of the hot water tank 5 can be used effectively. The possibility of running out of hot water can be reduced.

(Embodiment 9)
FIG. 19 is a configuration diagram of the heat pump water heater according to the ninth embodiment of the present invention, FIG. 20 is an explanatory diagram showing discharge pressure with respect to the feed water temperature of the heat pump water heater, and FIG. 21 is a diagram of the pressure reducing device with respect to the feed water temperature of the heat pump water heater. It is explanatory drawing which shows a valve opening degree.

In the present embodiment, the difference from the second embodiment is that the signal from the feed water temperature detecting means 8 that detects the feed water temperature that is the water-side inlet water temperature of the refrigerant-to-water heat exchanger 2 and the outside air temperature that detects the outside air temperature. The control means 11 for determining the initial valve opening degree according to the signal from the detection means 16 is provided. In addition, the part of the same code | symbol as Embodiment 2 has the same structure, and abbreviate | omits description.

  Next, the operation and action will be described. In FIG. 20, the horizontal axis represents the feed water temperature, which is the water-side inlet water temperature of the refrigerant-to-water heat exchanger 2, and the vertical axis represents the discharge pressure, so that the outside air temperature (for example, summer 35 ° C, intermediate period 20 ° C, winter The relationship of the discharge pressure with respect to the feed water temperature when the valve opening of the pressure reducing device 3 is made constant with 5 ° C) as a parameter is shown. As can be seen from the drawing, the discharge pressure increases as the energy (summer> intermediate> winter) that the evaporator 4 obtains from atmospheric heat is larger.

  Now, in FIG. 20, what has been described in FIG. 17 is valid for each outside air temperature (summer, intermediate period, winter). Furthermore, if the relationship between the feed water temperature described in FIG. 18 and the valve opening degree of the pressure reducing device 3 is obtained for each outside air temperature (summer, intermediate period, winter), it is as shown in FIG.

  That is, in FIG. 21, the horizontal axis represents the feed water temperature, which is the water-side inlet water temperature of the refrigerant-to-water heat exchanger 2, and the vertical axis represents the valve opening of the decompression device 3, and the outside air temperature (for example, summer 35 ° C.). The relationship between the valve opening of the decompression device 3 with respect to the feed water temperature is shown using the intermediate period 20 ° C. and winter 5 ° C. as parameters.

  Therefore, the valve opening Z, which is the reaching valve opening described in the second embodiment, is obtained in advance with respect to the feed water temperature using the outside air temperature as a parameter, and is stored in the initial valve opening storage means 14. . At the start of the hot water supply operation, the control means 11 uses the signal from the feed water temperature detection means 8, the signal from the outside air temperature detection means 16, and the signal from the initial valve opening degree storage means 14 to determine the initial valve opening (valve). Obtain the opening Z).

  And after the control means 11 sets the valve opening degree of the decompression device 3 to the valve opening degree Z, the hot water supply heating operation is started.

  As described above, since the initial valve opening is set according to the feed water temperature and the outside air temperature, the hot water in the hot water mixed layer region of the hot water tank 5 can also be boiled, and therefore, even if the outside air temperature changes. Since the hot water volume of the hot water tank 5 can always be effectively used, the possibility of hot water running out can be reduced.

(Embodiment 10)
FIG. 22 is a configuration diagram of the heat pump water heater according to the tenth embodiment of the present invention, and FIG. 23 is an explanatory diagram showing a target discharge temperature with respect to the outside air temperature of the heat pump water heater.

  The present embodiment is different from the first embodiment in that the control means 11 for determining the target discharge temperature is provided according to the signal from the outside air temperature detecting means 16 for detecting the outside air temperature. . In addition, the part of the same code | symbol as Embodiment 1 has the same structure, and abbreviate | omits description.

  Next, the operation and action will be described. In general, as the outside air temperature increases, the energy that the evaporator 4 obtains from atmospheric heat increases. Accordingly, since the refrigerant circulation amount increases, the valve opening of the decompression device 3 needs to be increased (opened) in order to make the discharge temperature and discharge pressure of the compressor 1 equal to or lower than the upper limit discharge temperature and the upper limit discharge pressure. There is.

Therefore, the relationship of FIG. 2 shown in the first embodiment is obtained in advance by changing the outside air temperature. Then, the target discharge temperature Y is obtained with respect to the outside air temperature as shown in FIG. That is, FIG. 23 shows the change of the target discharge temperature with respect to the outside air temperature, with the outside air temperature on the horizontal axis and the target discharge temperature on the vertical axis.

  A change in the target discharge temperature with respect to the outside air temperature is obtained in advance and stored in the target discharge temperature storage unit 12. At the start of the hot water supply operation, the control means 11 obtains the target discharge temperature from the signal from the outside air temperature detection means 16 and the signal from the target discharge temperature storage means 12. Further, the control means 11 detects the discharge temperature with a signal from the discharge temperature detection means 13.

  If the current discharge temperature is higher than the target discharge temperature, the control means 11 controls to increase (open) the opening of the decompression device 3. Conversely, if the current discharge temperature is lower than the target discharge temperature, the control means 11 performs control so as to reduce (close) the opening of the decompression device 3.

  As described above, since the valve opening degree of the pressure reducing device 3 is controlled so as to reach the target discharge temperature, even if the outside air temperature changes, an appropriate refrigerant circulates in the refrigerant circuit at all times. The durability is high and the driving efficiency can be improved.

(Example 11)
FIG. 24 is a configuration diagram of the heat pump water heater according to the eleventh embodiment of the present invention, and FIG. 25 is an explanatory diagram showing a target discharge temperature and a discharge pressure with respect to the water supply temperature of the heat pump water heater.

  In this example, the difference from the first embodiment is that the target discharge temperature is determined according to the signal from the feed water temperature detecting means 8 that detects the feed water temperature that is the water side inlet water temperature of the refrigerant-to-water heat exchanger 2. In other words, the control means 11 is provided. In addition, the part of the same code | symbol as Embodiment 1 has the same structure, and abbreviate | omits description.

  Next, the operation and action will be described. As described with reference to FIG. 16 of the eighth embodiment, a mixed layer in which the high temperature hot water and the low temperature water are mixed is formed in a portion where the high temperature hot water and the low temperature water are in contact with each other. And although the water in this mixing tank is sent to the refrigerant | coolant versus water heat exchanger 2, the temperature (water supply temperature) of the water sent to this refrigerant | coolant versus water heat exchanger 2 becomes high with time.

  FIG. 25 shows changes in the target discharge temperature and discharge pressure with respect to the water supply temperature, with the water supply temperature on the horizontal axis and the target discharge temperature and discharge pressure on the vertical axis. In the figure, the alternate long and short dash line indicates the case where the target discharge temperature is constant (target discharge temperature Tg1). In this case, the discharge pressure increases as the feed water temperature rises, and sometimes exceeds the upper limit discharge pressure.

  Therefore, when the feed water temperature that is the water-side inlet water temperature of the refrigerant-to-water heat exchanger 2 is Twx, the target discharge temperature Tg1 is changed to a target discharge temperature Tg2 (Tg1> Tg2) that is lower than the target discharge temperature Tg1. Further, the control means 11 detects the discharge temperature with a signal from the discharge temperature detection means 13.

  In this case, since the current discharge temperature is higher than the target discharge temperature, the control means 11 controls to increase (open) the opening of the decompression device 3. As a result, as shown by the solid line in FIG. 25, the discharge pressure decreases from P1 to P2 (P1> P2).

  As described above, when the feed water temperature sent from the mixed layer in the hot water tank 5 to the refrigerant-to-water heat exchanger 2 becomes high, the target discharge temperature is set low, and further, this low target discharge temperature is set. In order to control the valve opening of the pressure reducing device 3, the appropriate refrigerant circulates in the refrigerant circuit at all times even if the feed water temperature changes, so there is no abnormal temperature rise or abnormal pressure rise, high durability, and high operating efficiency. Can do better.

(Example 12)
FIG. 26 is a configuration diagram of the heat pump water heater according to the twelfth embodiment of the present invention, and FIG. 27 is an explanatory diagram showing a target discharge temperature with respect to the boiling temperature of the heat pump water heater.

  In the present embodiment, the difference from the first embodiment is that the target boiling temperature that stores the target boiling temperature that is the target temperature of the boiling temperature that is the water-side outlet water temperature of the refrigerant-to-water heat exchanger 2 is stored. The control means 11 for determining the target discharge temperature is provided according to the temperature storage means 19. In addition, the part of the same code | symbol as Example 1 has the same structure, and abbreviate | omits description.

  Next, the operation and action will be described. Generally, in order to raise the boiling temperature, it is necessary to raise the temperature of the refrigerant circulating in the refrigerant-to-water heat exchanger 2. Therefore, the relationship of FIG. 2 shown in Embodiment 1 is obtained in advance by changing the boiling temperature.

  And when the target discharge temperature Y is calculated | required with respect to the boiling temperature, it will become like FIG. That is, FIG. 27 shows the relationship of the target discharge temperature with respect to the boiling temperature, with the boiling temperature on the horizontal axis and the target discharge temperature on the vertical axis.

  Therefore, the relationship between the target discharge temperature and the boiling temperature is obtained in advance and stored in the target discharge temperature storage means 12. At the start of the hot water supply operation, the control means 11 obtains the target discharge temperature from the signal from the target boiling temperature storage means 19 and the signal from the target discharge temperature storage means 12.

  Further, the control means 11 detects the discharge temperature with a signal from the discharge temperature detection means 13. And the valve opening degree of the decompression device 3 is controlled so that the discharge temperature becomes the target discharge temperature.

  Instead of the relationship between the target discharge temperature and the boiling temperature shown in FIG. 27, substantially the same effect can be obtained even if the target discharge temperature is obtained by the following simplified relationship. That is, the target discharge temperature is set higher by a predetermined temperature ΔT than the target boiling temperature. Since the operation and action are the same as described above, description thereof is omitted.

  In each of the above embodiments, the refrigerant is not particularly described. However, any refrigerant may be used as long as it is used in such a device, for example, HCFC (R22) refrigerant, HFC refrigerant (R410A). ) Refrigerant, CO2 refrigerant, propane refrigerant, etc. are conceivable.

  As described above, in order to control the valve opening degree of the pressure reducing device 3 so as to reach the target discharge temperature, even if the boiling temperature is changed, an appropriate refrigerant always circulates in the refrigerant circuit. There is no increase, durability is high, and driving efficiency can be improved.

  As described above, according to the heat pump water heater of the present invention, since the valve opening degree of the pressure reducing device is controlled so as to reach the target discharge temperature, the appropriate refrigerant is always circulated in the refrigerant circuit to improve the operation efficiency. It can be expected to expand to thermal equipment other than water heaters.

The block diagram which shows the heat pump water heater of Embodiment 1 of this invention Explanatory drawing which shows discharge temperature with respect to the opening degree of the decompression device of the heat pump water heater, discharge pressure, and efficiency The block diagram of the heat pump water heater of Embodiment 2 of this invention Explanatory drawing which shows the discharge temperature with respect to the operation time of the heat pump water heater The block diagram of the heat pump water heater of Embodiment 3 of this invention Explanatory drawing which shows the discharge temperature with respect to the operation time of the heat pump water heater The block diagram of the heat pump water heater of Embodiment 4 of this invention Explanatory drawing which shows the temperature of piping which has attached the discharge temperature detection means with respect to the temperature of the compressor after the operation stop of the heat pump water heater Configuration diagram of heat pump water heater of Embodiment 5 of the present invention The block diagram of the heat pump water heater of Embodiment 6 of this invention Explanatory drawing which shows the temperature of piping which has the discharge temperature detection means with respect to the time after the operation stop of the heat pump water heater Explanatory drawing which shows the determination time at the time of hot and cold with respect to the outside temperature of the heat pump water heater The block diagram of the heat pump water heater of Embodiment 7 of this invention Explanatory drawing which shows the valve opening degree of the decompression device with respect to the outside temperature of the heat pump water heater, and the refrigerant circulation amount The block diagram of the heat pump water heater of Embodiment 8 of this invention Explanatory drawing which shows the temperature of the hot water in a hot water tank with respect to the height direction of the hot water tank of the heat pump water heater Explanatory drawing which shows the discharge pressure with respect to the feed water temperature of the heat pump water heater Explanatory drawing which shows the valve opening degree of the pressure reduction device with respect to the feed water temperature of the heat pump water heater The block diagram of the heat pump water heater of Embodiment 9 of this invention Explanatory drawing which shows the discharge pressure with respect to the feed water temperature of the heat pump water heater Explanatory drawing which shows the valve opening degree of the pressure reduction device with respect to the feed water temperature of the heat pump water heater Configuration diagram of heat pump water heater of Embodiment 10 of the present invention Explanatory drawing which shows the target discharge temperature with respect to the outside temperature of the heat pump water heater The block diagram of the heat pump water heater of Embodiment 11 of this invention Explanatory drawing which shows the target discharge temperature and discharge pressure with respect to the feed water temperature of the heat pump water heater The block diagram of the heat pump water heater of Embodiment 12 of this invention Explanatory drawing which shows the target discharge temperature with respect to the boiling temperature of the heat pump water heater Configuration diagram of heat pump water heater in conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Refrigerant to water heat exchanger 3 Pressure reducing device 4 Evaporator 5 Hot water storage tank 6 Circulating pump 8 Feed water temperature detection means 11 Control means 13 Discharge temperature detection means 16 Outside air temperature detection means 17 Compressor temperature detection means 18 Time measurement means

Claims (1)

A compressor, a refrigerant-to-water heat exchanger, a decompression device for controlling the flow rate of the refrigerant, a refrigerant circulation circuit provided with an evaporator, a hot water storage tank, a circulation pump, a hot water supply circuit provided with the refrigerant-to-water heat exchanger, and a discharge temperature detection means for detecting the discharge temperature of the compressor, comprising a feed water temperature detecting means for detecting the water side inlet temperature of the refrigerant to water heat exchanger, startup of the compressor, the feedwater temperature detected A heat pump water heater in which the valve opening of the pressure reducing device is set to a preset initial valve opening in accordance with a signal from the means .

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