JPH0814657A - Heat pump hot water supply system - Google Patents

Abstract

PURPOSE:To improve durability of devices in a heat pump hot water supply system in which hot water is produced by using a heat pump. CONSTITUTION:The title hot water supply system is provided with a compressor 1, a refrigerant water heat exchanger 2, a pressure reducing device 3, an evaporator 4, a hot water storage tank 5, a circulating pump 6, a heating device 7 having a built-in heater 8, a first temperature detecting device 9, a second temperature detecting device 10, a revolution speed controlling means 11, a hot water temperature setting device 12, a precedent control device 13, a first control device 14 and an operation control device 15. A selection is made to turn on the heater 8 on an signal from the hot water temperature setting device 12 and signals of the first temperature detecting device 9, and the second temperature detecting device 10 are also determined. The flow rate of the circulating pump 6 is controlled by using the signals from the first temperature detecting device 9 and the second temperature detecting device 10 so that temperature of hot water at an outlet of the refrigerant-water heat exchanger 2 and the heater 7 is kept at a set hot water temperature. The heater 8 is turned off on a signal from the first temperature detecting device 9 so that the durability of the compressor 9 is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of reliability and heat quantity of stored hot water of a water heater using a heat pump.

[0002]

2. Description of the Related Art Conventionally, a water heater using a heat pump is shown in FIG.
As shown in, a refrigerant circuit including a compressor 1, a refrigerant-to-water heat exchanger 2, a pressure reducing device 3, and an evaporator 4, a hot water tank 5, a circulation pump 6, and a refrigerant-to-water heat exchanger 2 are connected to a hot water supply circuit. The high-temperature high-pressure superheated gas refrigerant discharged from the compressor 1 flows into the refrigerant-to-water heat exchanger 2, where the heat of condensation is used to remove the water sent from the circulation pump 6. It is heated and stored in the hot water storage tank 5. On the other hand, the refrigerant condensed and liquefied in the refrigerant-to-water heat exchanger 2 is decompressed by the decompression device 3 and flows into the evaporator 4. Then, here, the heat of the atmosphere is absorbed to be vaporized and returned to the compressor 1. At this time, considering the durability of the compressor 1 at high temperatures, the hot water temperature stored in the hot water storage tank 5 cannot be high. Therefore, in order to obtain a sufficient amount of hot water, the hot water storage tank 5 becomes large. In order to prevent this, as shown in FIG. 2, the hot water flowing out from the refrigerant-to-water heat exchanger 2 is heated by the heater 7
It is conceivable that the hot water is gradually heated from the upper part of the hot water storage tank 5 by heating it to a high temperature.

[0003]

However, in the above configuration, when the input of the heater 7 is constant, the refrigerant-to-water heat exchanger is used when the outlet hot water temperature of the heater 7 is constant. The temperature of the hot water flowing out of 2 changes depending on the feed water temperature and the amount of heat exchanged by the refrigerant-to-water heat exchanger 2. For example, when the outside air temperature rises, the amount of heat by the refrigerant-to-water heat exchanger 2 increases, the hot water temperature flowing out from the refrigerant-to-water heat exchanger 2 becomes high, and the temperature is high enough to damage the compressor 1. There is also a fear of becoming. If the input of the heater 7 is constant at 2 kW and the outlet hot water temperature of the heater 7 is set to 85 ° C., the supply water temperature in winter is 5 ° C., and the heating amount of the refrigerant-to-water heat exchanger 2 is 2 kW. The temperature of the hot water flowing out from the refrigerant-to-water heat exchanger 2 is 45 ° C.
Is. However, in the middle season, the feed water temperature is 20 ° C., and the heating amount of the refrigerant-to-water heat exchanger 2 is increased to 4 kW, so that the hot water temperature flowing out from the refrigerant-to-water heat exchanger 2 is increased to 63 ° C. In addition, since the high temperature hot water is gradually accumulated from the upper part of the hot water storage tank 5, the high temperature hot water and the low temperature water supplied in the hot water storage tank 5 conduct heat to lower the temperature of the hot water and increase the temperature of the low temperature water. As a result, a mixed layer of hot water and low temperature water is formed. Therefore, before the completion of boiling, the water in the mixed layer having a temperature higher than the actual feed water temperature starts to flow into the refrigerant-to-water heat exchanger 2. If the inlet water temperature of the refrigerant-to-water heat exchanger 2 changes from the supply water temperature of 20 ° C to the mixed layer hot water of 35 ° C under the above-mentioned intermediate season conditions, the hot-water temperature flowing out of the refrigerant-to-water heat exchanger 2 is 63 ° C. Can reach 68 ° C. In this way, when the hot water temperature rises, the discharge pressure of the compressor 1 also rises, the winding temperature of the motor rises, and the reliability of the compressor becomes a problem.

In order to ensure reliability, the operation must be stopped even when the temperature of the water flowing from the hot water storage tank 5 to the refrigerant / water heat exchanger 2 is low. In that case, the amount of heat stored in the hot water storage tank 5 decreases, and the hot water supply load cannot be satisfied.

[0005]

In order to solve the above-mentioned drawbacks, the present invention solves the above-mentioned drawbacks by a refrigerant circulation circuit in which a compressor, a refrigerant-to-water heat exchanger, a pressure reducing device and an evaporator are sequentially connected, a hot water tank, a circulation pump, A hot water supply circuit in which a refrigerant-to-water heat exchanger and a heater with a built-in heater are sequentially connected, a first temperature detector provided downstream of the refrigerant-to-water heat exchanger, and a second temperature provided downstream of the heater. A detector, a rotation speed control unit that controls the rotation speed of the circulation pump based on signals from the first temperature detector and the second temperature detector, and a hot water temperature setting device that sets the boiling water temperature of the hot water storage tank. A priority control unit that selects the energization of the heater with a signal from the hot water temperature setting device and determines a signal from the first temperature detector or the second temperature detector;
Even in the case of the temperature detector priority signal, the heater is controlled by the signal of the first temperature detector, and the first control unit switches to the first temperature detector priority, and the first temperature detector or the second temperature detector. The operation control unit controls the energization of the compressor and the heater by a signal from a container.

Further, in order to increase the amount of heat stored in the hot water, a third temperature detector is provided upstream of the refrigerant-to-water heat exchanger, and the compressor is generated by signals from the first temperature detector and the third temperature detector. Alternatively, it comprises a second control unit for controlling the energization of the heater.

[0007]

According to the present invention, the priority control section receives the signal from the hot water temperature setting device to select the energization of the heater, and deactivates the heater when the set hot water temperature is relatively low. At the same time, the rotation speed of the circulation pump is controlled by the signal from the first temperature detector so that the outlet hot water temperature of the refrigerant-to-water heat exchanger becomes constant. Then, when the outlet hot water temperature of the refrigerant-to-water heat exchanger becomes higher than the setting during continuous operation, the first temperature detector detects it and sends a signal to the operation control unit to stop the compressor. . Next, when the set hot water temperature is high, the heater is energized and the rotation speed of the circulation pump is controlled by the signal of the second temperature detector so that the hot water temperature at the outlet of the heater becomes constant. Then, when the outlet hot water temperature of the heater becomes higher than the set value during the continuous operation, the second temperature detector detects it and sends a signal to the operation control unit to energize the compressor and the heater. Stop. In this case, although the outlet hot water temperature of the heater is controlled to be constant, the heating amount of the refrigerant-to-water heat exchanger increases because the outside air temperature is high, and the outlet hot water of the refrigerant-to-water heat exchanger increases. When the temperature becomes higher than the set temperature, the first temperature detector detects the temperature and sends it to the first control unit to turn off the heater. Then, the operation is switched to the heat pump independent operation by the compressor and the operation is continued, and the first temperature detector again detects that the hot water temperature is high, and stops the operation of the compressor.

Next, in the operation in which the heater is energized, when the outside air temperature is high and the heating amount of the refrigerant-to-water heat exchanger is large, or the hot water in the mixed layer having a temperature higher than the initial feed water temperature is the refrigerant-to-water heat exchanger. In the case of flowing into the refrigerant, the first temperature detector indicates that the temperature of the refrigerant-to-water heat exchanger outlet is higher than the setting, while the temperature of the refrigerant-to-water heat exchanger inlet is set to the third temperature. The second by detecting with a detector
Send a signal to the control unit. When the signal of the third temperature detector is the same as the initial feed water temperature, the second control unit indicates that the temperature of the refrigerant-to-water heat exchanger outlet is higher than the setting, not the influence of the mixing layer. , Recognizing that the heating amount of the refrigerant-to-water heat exchanger is large, de-energizing the heater,
Only the heat pump by the compressor is operated alone. Further, when the third temperature detector is higher than the initial feed water temperature and sends the signal to the second controller, it is determined that the boiling water of the mixed layer is in operation, and the compressor is stopped, The heater alone operation is continued. Therefore, operation can be performed until the lower part of the hot water storage tank reaches a high temperature, and the heat quantity of hot water storage increases.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, 1 is a compressor, 2 is a refrigerant-to-water heat exchanger, 3 is a decompression device, 4 is an evaporator, and the compressor 1, the refrigerant-to-water heat exchanger 2 and the decompression device are shown. 3. The evaporator 4 is sequentially connected to form a refrigerant circulation circuit. 5
Is a hot water storage tank, 6 is a circulation pump, 7 is a heater having a built-in heater 8, and the hot water storage tank 5, the circulation pump 6, the refrigerant-to-water heat exchanger 2, and the heater 7 are sequentially connected to a hot water supply circuit. Make up. 9 is a first temperature detector, 10 is a second temperature detector downstream of the refrigerant-to-water heat exchanger,
It is provided downstream of the heater 7. Reference numeral 11 denotes a rotation speed control unit, which controls the rotation speed of the circulation pump 6 by signals of the first temperature detector 9 and the second temperature detector 10. Reference numeral 12 denotes a hot water temperature setting device, which sets the boiling water temperature of the hot water storage tank 5. Reference numeral 13 is a priority control unit, which selects the energization of the heater 8 by the signal of the hot water temperature setting device 12 and determines the priority of the signal of the first temperature detector 9 or the second temperature detector 10. 14 is a first control unit,
Even in the priority signal of the second temperature detector 10, the first signal
The heater 8 is controlled by the signal of the temperature detector 9, and the first temperature detector 9 is switched to the priority. Reference numeral 15 denotes an operation control unit, which controls energization of the compressor 1 and the heater 8 by a signal from the first temperature detector 9 or the second temperature detector 10. Reference numeral 16 is a third temperature detector, which is provided upstream of the refrigerant-to-water heat exchanger 2. 17 is the second
The control unit controls the energization of the compressor 1 or the heater 8 by the signals of the first temperature detector 9 and the third temperature detector 16.

In the above structure, first, the case where the boiling water temperature of the hot water storage tank 5 is set low and the hot water temperature can be obtained by the heat pump alone will be described. In this case, the energization of the heater 8 is stopped in response to the signal from the hot water temperature setting device 12. Then, the high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 1 flows into the refrigerant-to-water heat exchanger 2, where it heats the water sent from the circulation pump 6. At this time, the refrigerant condensed and liquefied by the heat dissipation effect is decompressed by the decompression device 3 and flows into the evaporator 4. Then, it absorbs atmospheric heat to be vaporized and returned to the compressor 1. on the other hand,
The water flowing out from the lower part of the hot water storage tank 5 is the circulation pump 6
It flows into the refrigerant-to-water heat exchanger 2 via, is heated by the heat of condensation of the refrigerant, and is stored in the upper part of the hot water storage tank 5.
Here, the outlet hot water temperature of the refrigerant-to-water heat exchanger 2 is set to the first hot water temperature.
The temperature detector 9 detects and sends a signal to the rotation speed control unit 11 to control the rotation speed of the circulation pump 6 so that the outlet hot water temperature becomes the set hot water temperature. Then, while continuing this operation, the hot water of the set hot water is stored in the hot water storage tank 5.

Next, the case where the boiling water temperature is set high will be described. In this case, the heater 8 is energized in response to the signal from the hot water temperature setting device 12. Then, the water heated by the refrigerant-to-water heat exchanger 2 is further heated by the heater 7 to a higher temperature and stored in the upper part of the hot water storage tank 5. Here, the second temperature detector 10 detects the outlet hot water temperature of the heater 7, sends a signal to the rotation speed control unit 11, and the circulation pump 6 is controlled so that the outlet hot water temperature becomes the set hot water temperature.
Control the rotation speed of. Here, the refrigerant-to-water heat exchanger 2
If the water heated in step 1 becomes abnormally high in temperature, the first temperature detector 9 detects it and sends a signal to the first controller 14 to stop energizing the heater 8. And
The single heating operation in the refrigerant-to-water heat exchanger 2 is switched to the rotation speed control operation of the circulation pump 6 based on the signal from the first temperature detector 9. Therefore, the outlet hot water temperature of the refrigerant-to-water heat exchanger 2 does not become abnormally high, and the reliability of the compressor 1 is improved.

Next, the case of increasing the amount of heat stored in the hot water will be described. In this case, when the water heated in the refrigerant-to-water heat exchanger 2 becomes abnormally high in temperature, the first temperature detector 9 detects it and the refrigerant-to-water heat exchanger 2
The water temperature at the inlet of is detected by the third temperature detector 16, and the signals of the first temperature detector 9 and the third temperature detector 16 are sent to the second controller 17. When the inlet water temperature of the refrigerant-to-water heat exchanger 2 is the same as the initial feed water temperature from the signal from the third temperature detector 16, the second control unit 1
The electricity supply to the heater 8 is stopped via 7, and the operation is switched to the single heating operation in the refrigerant-to-water heat exchanger 2. on the other hand,
When the inlet water temperature of the refrigerant-to-water heat exchanger 2 is higher than the initial feed water temperature, the compressor 1 is stopped via the second controller 17, and the heater 8 is operated independently. Therefore, operation can be performed until the lower part of the hot water storage tank 5 reaches a high temperature, and the heat quantity of hot water storage increases.

[0014]

As described above, the heat pump water heater of the present invention includes a refrigerant circulation circuit in which a compressor, a refrigerant-to-water heat exchanger, a pressure reducing device, and an evaporator are sequentially connected, a hot water tank, a circulation pump, and the refrigerant. A hot water supply circuit in which a water heat exchanger and a heater with a built-in heater are sequentially connected, a first temperature detector provided downstream of the refrigerant water heat exchanger, and a second temperature detection provided downstream of the heater. And a rotation speed control unit for controlling the rotation speed of the circulation pump by the signals of the first temperature detector and the second temperature detector, and a hot water temperature setting device for setting the boiling hot water temperature of the hot water storage tank. A priority control unit that selects the energization of the heater by a signal from the hot water temperature setting device and determines a signal from the first temperature detector or the second temperature detector;
Even in the case of the temperature detector priority signal, the heater is controlled by the signal of the first temperature detector, and the first control unit switches to the first temperature detector priority, and the first temperature detector or the second temperature detector. When the hot water temperature setter has a relatively low temperature, the operation control unit that controls the energization of the compressor and the heater by a signal of the heater is provided, and the priority control unit selects the energization of the heater by the signal of the hot water temperature setter First, the heater is de-energized, and the rotation speed of the circulation pump is controlled by the signal of the first temperature detector so that the outlet hot water temperature of the refrigerant-to-water heat exchanger becomes constant. When the set hot water temperature is high, the heater is energized and the rotation speed of the circulation pump is controlled by the signal from the second temperature detector so that the hot water at the outlet of the heater becomes constant. Then, when the outlet hot water temperature of the heater becomes higher than the setting during continuous operation,
The second temperature detector detects this and sends a signal to the operation controller to stop energizing the compressor and the heater. In this case, even if the outlet hot water temperature of the heater is controlled to be constant, if the outlet hot water temperature of the refrigerant-to-water heat exchanger becomes higher than the set value, the first temperature detector detects it. It is sent to the first control unit and the heater is de-energized. Then, the operation is switched to the heat pump independent operation by the compressor and the operation is continued, and the first temperature detector again detects that the hot water temperature is high, and stops the operation of the compressor. Therefore, the outlet hot water temperature of the refrigerant-to-water heat exchanger does not become abnormally high, and the reliability of the compressor is improved.

Next, a third temperature detector is provided upstream of the refrigerant-to-water heat exchanger, and the energization of the compressor or the heater is controlled by the signals of the first temperature detector and the third temperature detector. When the outlet hot water temperature of the refrigerant-to-water heat exchanger is higher than the set temperature, the second control unit for receiving the signal of the third temperature detector is received together with the signal of the first temperature detector. The second controller controls the energization of the compressor or the heater. Here, when the inflow water temperature of the refrigerant-to-water heat exchanger is the same as the initial supply water temperature, the energization of the heater 8 is stopped via the second control unit 17, and the refrigerant-to-water heat exchanger 2 Switch to single heating operation in. On the other hand, when the inlet water temperature of the refrigerant-to-water heat exchanger 2 is higher than the initial feed water temperature, the compressor 1 is stopped via the second controller 17, and the heater 8
It becomes an independent operation. Therefore, operation can be performed until the lower part of the hot water storage tank 5 reaches a high temperature, and the heat quantity of hot water storage increases.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a conventional heat pump water heater.

[Explanation of symbols]

 1 Compressor 2 Refrigerant-to-Water Heat Exchanger 3 Decompressor 4 Evaporator 5 Hot Water Tank 6 Circulation Pump 7 Heater 8 Heater 9 First Temperature Detector 10 Second Temperature Detector 11 Rotation Speed Controller 12 Hot Water Temperature Setter 13 Priority control unit 14 First control unit 15 Operation control unit 16 Third temperature detector 17 Second control unit

Claims (2)

[Claims] 1. A refrigerant circulation circuit in which a compressor, a refrigerant-to-water heat exchanger, a pressure reducing device, and an evaporator are sequentially connected, a hot water tank, a circulation pump, the refrigerant-to-water heat exchanger, and a heater with a built-in heater. A connected hot water supply circuit, a first temperature detector provided downstream of the refrigerant-to-water heat exchanger, a second temperature detector provided downstream of the heater, the first temperature detector and the second A rotation speed control unit that controls the rotation speed of the circulation pump with a signal from a temperature detector, a hot water temperature setting device that sets the boiling hot water temperature of the hot water storage tank, and the heater energization with a signal from the hot water temperature setting device. And a second priority control unit that determines the signal of the first temperature detector or the second temperature detector,
Even in the case of the temperature detector priority signal, the heater is controlled by the signal of the first temperature detector, and the first control unit switches to the first temperature detector priority, and the first temperature detector or the second temperature detector. A heat pump water heater comprising an operation control unit that controls energization of the compressor and the heater by a signal from a heater. 2. A third temperature detector is provided upstream of the refrigerant-to-water heat exchanger, and energization of the compressor or the heater is controlled by signals of the first temperature detector and the third temperature detector. A heat pump water heater including a second control unit.