JP3019732B2 - Heat pump water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A conventional water heater using a heat pump is disclosed in Japanese Patent Publication No. 62-22379. However, the ability and the frosted evaporator 4 in winter is that begins to occur
It begins to decrease operating efficiency of the evaporation temperature frosting progresses
With the decrease , the capacity and the operation efficiency decrease remarkably.
Then, if the operation is continued, the refrigerant in the evaporator 4
It can not be sufficiently evaporated, a liquid refrigerant returns to the compressor 1. The compressor 1 performs liquid compression, which is not preferable in terms of durability of the compressor 1.

To prevent this, a four-way valve is provided in the middle of the compressor 1 and the condenser 2, and when frost occurs, the four-way valve is switched to defrost the superheated gas of the compressor 1. The configuration is clear.

[0004]

However, in the above-described conventional configuration, the hot water boiled in the condenser 2 of the heat pump is further increased during the combined operation with the auxiliary heater 10.
Since the auxiliary heater 10 heats to the set temperature,
The temperature of the hot water boiled at the pump is
It is lower than the temperature of the hot water. Therefore, heat pump
Operates at a low condensation temperature. Therefore, the evaporating temperature is operated at a low temperature as the condensing temperature decreases. Obedience
Therefore, when the heat pump is operating alone and
When comparing the rotation times, if the evaporation temperature is the same, the amount of frost formation and
The progress of frost formation is the same, but the outside air
However, the temperature of the refrigerant flowing through the evaporator 4 (evaporation temperature) is low.
Be driven. That is, during the combined operation with the auxiliary heater 10
The temperature difference between the evaporation temperature and the defrosting start temperature becomes smaller. Therefore, if the defrosting start temperature is set to be the same as that of the heat pump alone operation, there is a condition that the evaporating temperature is equal to or lower than the defrosting start temperature in severe cold even though frost is not formed from the beginning of the operation.
After starting the operation, the operation is switched to the defrosting operation in a short time. Ma
In addition, outside air where the evaporation temperature in the initial operation is higher than the defrost start temperature
Even when operating under conditions, evaporation temperature and defrost
Because the temperature difference from the starting temperature is small,
The evaporating temperature drops to the defrost starting temperature, and the mode is frequently switched to the defrosting operation despite the sufficient capacity and operation efficiency. Therefore, since the heating operation time is shortened, the amount of heat stored in the hot water storage tank is reduced, and the hot water supply load cannot be satisfied. In addition, the driving efficiency is deteriorated. Conversely, if the defrost start temperature is set to the combined operation, during the heat pump operation, since the temperature difference between the evaporation temperature and the defrost start temperature is large, the operation is not switched to the defrost operation until frost formation proceeds considerably. Therefore, there is a disadvantage that the liquid compressor is operated at a low capacity and a low efficiency and the durability of the compressor is reduced. A first object of the present invention is to eliminate the above-mentioned disadvantages.

Further, as a second disadvantage, when the four-way valve is switched during defrosting to perform defrosting with the superheated gas of the compressor 1, if the operation of the pump 9 is continued during the defrosting, the condenser 2 Has a vaporizing effect and absorbs heat from water. Therefore, the water is frozen inside the condenser 2 and the water is not circulated. Therefore, when the auxiliary heater 10 is energized, an abnormal temperature rise occurs, and the durability of the auxiliary heater 10 is impaired. After the completion of defrosting, the auxiliary heater 1
Despite the high temperature of the water within 0 due to the residual heat during the heating operation, if the auxiliary heater 10 is energized simultaneously, overshoot occurs and the reliability of the auxiliary heater 10 is impaired. Therefore, a second object is to improve reliability.

[0006]

In order to achieve the first object, the present invention provides a compressor, a four-way valve, a refrigerant-to-water heat exchanger,
The decompression device, the evaporator, the evaporator and the compressor
A coolant circulation circuit for supplying sequentially refrigerant connected via the valve, before
The compressor, the four-way valve, the evaporator, and the pressure reducing device.
Check valve provided in a row, the refrigerant to water heat exchanger, the refrigerant pair
Connect the water heat exchanger and the compressor via the four-way valve and sequentially
A refrigerant defrost circuit for flowing a refrigerant, a lower part of a hot water storage tank , a circulation pump, the refrigerant-to-water heat exchanger, a heater, the heater and the
A hot water supply circuit that connects the upper part of the hot water storage tank and sequentially flows water, and detects a refrigerant temperature at the evaporator inlet, and from the refrigerant circulation circuit
A refrigerant temperature detector for transmitting a plurality of signals (set temperatures) for switching to the refrigerant defrost circuit, an operation recognition unit for recognizing the compressor alone operation or a combined operation of the compressor and the heater, and the operation recognition in parts of the signal consists of the evaporation temperature control unit for switching the set temperature of the refrigerant temperature detector, said compression
The refrigerant temperature is detected during the combined operation as opposed to the single operation.
This is to lower the set temperature of the vessel.

[0007] In order to achieve the second object consists defrosting control unit for controlling the circulation pump and the heater switches the four-way valve in the signal of the refrigerant temperature sensor, the cold
Receiving a first signal of a medium temperature detector and receiving the first signal from the medium temperature detector;
To switch on the circulation pump and the heater.
Stopping, after receiving the first signal, from the first signal
The second high temperature signal is received and returned to the refrigerant circuit.
Switch on and switch on the circulation pump, the heater
Is applied with a delay .

Next, in order to improve the durability of the equipment and shorten the boiling time, the detection of the first signal of the refrigerant temperature detector which switches to the refrigerant defrosting circuit is performed by the refrigerant circulation circuit.
It comprises a dead zone control section which has a dead zone time period which is detected once at the first time after the start of the lifting operation and is not detected for a fixed time thereafter.

Further, in order to improve the durability of the compressor, a clock, counting means for integrating the number of receptions of the first signal of the refrigerant temperature detector for switching to the refrigerant defrosting circuit, and a predetermined time of the clock When the counting means reaches a certain number of times within a time period , the operation of the compressor is stopped and heating is performed.
It is composed of an operation control unit for switching to single operation of the vessel .

[0010]

According to the present invention, the operation recognizing section recognizes whether the compressor is operated alone or the compressor and the heater are operated in combination, and sends a signal to the evaporating temperature control section. Then, the set temperature of the refrigerant temperature detector is made different between the compressor alone operation and the heater combined operation, and the set temperature is set lower during the combined heater operation to remove the refrigerant from the refrigerant circulation circuit. Switch to circuit
To do. Therefore, even if the evaporating temperature becomes low during the operation in combination with the heater, the operation is not frequently switched to the defrosting operation or the heating operation is not stopped. In addition, frost formation does not significantly progress during the compressor alone operation, and the durability of the compressor due to low capacity, low efficiency operation, and liquid compression does not decrease.

In response to the first signal of the refrigerant temperature detector, the four-way valve is switched to perform a defrosting operation of the evaporator in the refrigerant defrosting circuit . At that time, the defrost control unit stops energization of the circulation pump and the heater. Then, the completion of the defrost is received by the second signal of the refrigerant temperature detector, and the circulation pump is operated. Thereafter, the heater is energized with a delay. Accordingly, the heater is not energized while the water-side passage of the refrigerant-to-water heat exchanger is blocked by freezing. Further, since the heater is energized after the circulation pump is energized, residual heat of the heater is removed. Therefore, the heating operation after the completion of the defrost can be stably started.

Next, under the frost formation conditions in winter, when the evaporator is started to operate in the frost formation state, the evaporation temperature drops sharply. However, this is detected by the first signal of the refrigerant temperature detector, and the defrosting operation is performed, so that the refrigerant is completely defrosted, and the heating operation is started again and is continued for a certain period of time. Therefore, even if the operation is started in the frosted state at the start of the operation, the durability, ability, and efficiency of the device are improved.

[0013] When operated under severe cold conditions, the evaporating temperature is significantly reduced to be lower than the first signal of the refrigerant temperature detector. Therefore, defrosting operation is frequently performed. The count is accumulated by the counting means, and when a predetermined number of times is reached within the predetermined time of the clock, the operation control unit stops the operation of the compressor and performs the heater alone operation, so that the durability of the compressor is improved. .

[0014]

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, 1 is a compressor, 2 is a four-way valve,
Reference numeral 3 denotes a refrigerant-to-water heat exchanger, 4 denotes a pressure reducing device, and 5 denotes a check valve, which is provided in parallel with the pressure reducing device 4. 6 is an evaporator, the compressor 1, the four-way valve 2, the refrigerant to water heat exchanger 3, the decompressor 4, before Symbol evaporator 6, the evaporated
The compressor and the compressor are connected via a four-way valve and the refrigerant flows sequentially.
A refrigerant circulation circuit. In addition, the compressor 1, the
The four-way valve 2, the evaporator 4, and the decompression device were connected in parallel.
Check valve 5, refrigerant-to-water heat exchanger 3, refrigerant-to-water heat exchanger
And a compressor via a four-way valve to remove refrigerant
Construct a frost circuit. 7 is a hot water tank, 8 is a circulation pump, 9 is a heater, and a lower portion of the hot water tank 7, the circulation pump 8, the refrigerant-to-water heat exchanger 3, the heater 9, the hot water tank 7
Is connected to form a hot water supply circuit for sequentially flowing water. 1
Reference numeral 0 denotes a refrigerant temperature detector, which is a refrigerant temperature at the inlet of the evaporator 6.
The refrigerant circulation circuit and the refrigerant defrost circuit
A plurality of switching signals (set temperatures) are transmitted . An operation recognition unit 11 recognizes whether the compressor 1 is operated alone or the compressor 1 and the heater 9 are operated in combination. 12
Is evaporation temperature control unit, switching the set temperature of the refrigerant temperature detector 10 in the signal of the operation recognition section 11, when combined operation of the heater 9 to reduce the set temperature of the refrigerant temperature detector 10. Reference numeral 13 denotes a defrost control unit which switches the four-way valve by the first signal of the refrigerant temperature detector 10 to perform the refrigerant defrost.
While configuring a circuit, the energization of the circulation pump 8 and the heater 9 is stopped, and after receiving the first signal, a second signal of a higher temperature signal than the first signal is received, and
Switching back to the refrigerant circulation circuit and the circulation pump 8
And the heater 9 is energized with a delay. Reference numeral 14 denotes a dead zone control unit which detects the first signal of the refrigerant temperature detector 10 for switching to the refrigerant defrosting circuit, and detects the first signal.
A dead zone time is provided that is detected once at the first time after the start of the boiling operation, and is not detected for a fixed time thereafter. Fifteen
Is a clock, and 16 is a counting means, which accumulates the number of receptions of the first signal of the refrigerant temperature detector 10 which switches to the refrigerant defrosting circuit at the start of the clock 15.
Reference numeral 17 denotes an operation control unit. When the count means 16 reaches a predetermined number of times within a predetermined time period of the clock 15 ,
Stop operation of the compressor 1, by energizing the heater 9
Switch to heater alone operation .

A first embodiment having the above configuration will be described. In the heating operation of the heat pump, the high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 1 passes through the four-way valve 2 and flows into the refrigerant-to-water heat exchanger 3, where it is sent from the circulation pump 8. Heat the water. At this time, the refrigerant condensed and liquefied by the heat radiation action is depressurized by the decompression device 4 and flows into the evaporator 6. Then, it absorbs atmospheric heat to evaporate and return to the compressor 1. On the other hand, the water flowing out from the lower part of the hot water storage tank 7 flows into the refrigerant-to-water heat exchanger 3 through the circulation pump 8, is heated by the heat of condensation of the refrigerant, and is stored in the upper part of the hot water storage tank 7. Here, during the operation in winter, frost forms on the surface of the evaporator 6, and the evaporation temperature of the refrigerant flowing through the evaporator 6 decreases as the frost progresses, and the heating capacity and efficiency also decrease.

Next, the combined operation of the heater 9 will be described. In this case, the single operation of the heat pump and the heater 9 are simultaneously energized, and the water heated by the refrigerant-to-water heat exchanger 3 is reheated by the heater 9. Therefore, the heating capacity is increased and the circulation flow rate of the circulation pump 8 is increased as compared with the heat pump alone operation. Therefore, the operation is performed in a state where the condensing temperature decreases and the evaporation temperature decreases accordingly. However, the operation recognizing unit 11 recognizes that the combined operation is being performed, and sends a signal to the evaporating temperature control unit 12 so that the first set temperature of the refrigerant temperature detector 10 is set low. The operation is not switched to the defrosting operation even under the same outside air temperature condition as the heat pump alone operation.

Next, a second embodiment will be described. In the defrosting operation, the gas refrigerant discharged from the compressor 1 passes through the four-way valve 2 and flows into the evaporator 6, where the frost is melted by the heat of condensation. Then, the low-temperature liquid refrigerant flows into the compressor 1 through the check valve 5, the refrigerant-to-water heat exchanger 3, and the four-way valve 2. At this time, since the low-temperature liquid refrigerant passing through the refrigerant-to-water heat exchanger 3 takes heat from water, the water-side flow path may freeze and be blocked.
And since the heater 9 is stopped, the heater 9
Never overshoot. When the defrosting is about to end, the amount of the gas refrigerant discharged from the compressor 1 that is deprived of heat by the defrosting also decreases, so that the refrigerant temperature of the refrigerant temperature detector 10 increases and the refrigerant temperature is detected. Then, a signal is sent to the defrost control unit 13, the four-way valve 2 is switched again, the circulating pump 8 is operated, and the residual heat of the heater 9 is removed. After that, the heater 9 is energized with a delay. Therefore, the heater 9 does not overshoot and the durability is improved.

Next, a third embodiment will be described.
In the operation modes of the heating operation and the defrosting operation, the evaporation temperature after the start of the operation is different between when the operation is started with the evaporator 6 frosted and when the operation is started without the frost. Different, the time change of the temperature drop is also different. When the operation is started with no frost, the operation is described in the above operation. However, when the operation is started with the frost formed, the temperature drops to the first signal of the refrigerant temperature detector 10 in a short time. I do. Then, a signal of the defrosting operation is sent to the dead zone control unit 14. Then, the defrosting operation is started, the defrosting is completely performed, and the heating operation is performed again. After that, frost formation progressed over time,
The temperature of the refrigerant temperature detector 10 gradually decreases. Then, although the temperature drops to the first signal of the refrigerant temperature detector 10, the heating operation is continued until a predetermined time set by the dead zone control unit 14. Therefore, even if the operation is started in a frosted state, the compressor does not perform liquid compression, and the durability is improved. Further, since the defrosting operation is not performed for a predetermined time, the boiling time is reduced.

Next, a fourth embodiment will be described.
During operation under severe cold conditions, the evaporating temperature during the heating operation is significantly reduced to be lower than the first signal of the refrigerant temperature detector. Therefore, defrosting operation is frequently performed. The count is counted by the counting means 16, and when the count reaches a certain number within the predetermined time of the clock 15, the operation control unit 17 stops the operation of the compressor 1 and performs the heater alone operation. Therefore, since the durability of the compressor 1 is improved and the operation is switched to the operation using the heater, the hot water supply load can be satisfied without being affected by the outside air temperature condition.

[0021]

As described in the above embodiments, the heat pump water heater of the present invention comprises a compressor, a four-way valve, a refrigerant-to-water heat exchanger, a pressure reducing device, an evaporator, and the evaporator and the compressor.
A refrigerant circulation circuit connected through a four-way valve to sequentially flow the refrigerant, the compressor, the four-way valve, the evaporator, and the pressure reducing device;
Check valve provided in parallel with the installation, the refrigerant-to-water heat exchanger,
The refrigerant-to-water heat exchanger and compressor are connected via the four-way valve.
And a refrigerant defrost circuit for sequentially flowing the refrigerant, a lower part of the hot water tank , a circulation pump, the refrigerant-to-water heat exchanger, a heater, and the heater.
A hot water supply circuit that connects the hot water tank upper portion and sequentially flows water, and detects a refrigerant temperature at an inlet of the evaporator, and detects the refrigerant circulation circuit.
A refrigerant temperature detector for transmitting a plurality of signals (set temperatures) for switching to the refrigerant defrost circuit from the above, an operation recognition unit for recognizing the compressor alone operation or the combined use of the compressor and the heater, and the operation An evaporating temperature control unit that switches the set temperature of the refrigerant temperature detector with a signal from the recognition unit, and lowers the set temperature of the refrigerant temperature detector during the combined operation with respect to the compressor alone operation to perform a defrosting operation. The number of times and the boiling operation time are reduced.

Also, the signal of the refrigerant temperature detectorTurn off the four-way valve
ChangeDefrost controlling circulation pump and heater
A control unit, and outputs a first signal of the refrigerant temperature detector.Receiving
And switched to the refrigerant defrost circuit,The circulation pump and
And the heater is de-energized, and the first signalReceive
After that, a higher temperature signal than the first signalofSecond signalReceive
To switch to the refrigerant circuit againThe circulation port
The heater is energized, the heater is energized with a delay, and the heater is energized.
Prevent overshoot of heater and improve durability
You.

Next, the detection of the first signal of the refrigerant temperature detector for switching to the refrigerant defrosting circuit is performed by the refrigerant circulation circuit.
Equipped with a dead zone control unit that detects the first time after the start of the boiling operation and then does not detect it for a certain period of time, when the operation is started in the frosted state, the first time after the operation is started Performs defrosting by detecting the refrigerant temperature detector, and thereafter, does not perform defrosting for a predetermined time, thereby preventing liquid compression of the compressor, improving durability, and reducing the number of defrosting operations. To shorten the boiling time.

The clock and the refrigerant defrosting circuit
Counting means for accumulating the number of receptions of the first signal of the switched refrigerant temperature detector ; and operating the compressor when the counting means reaches a certain number within a predetermined time period of the clock.
When the operation is carried out under severe cold conditions, the evaporation temperature drops significantly, becomes less than the first signal of the refrigerant temperature detector, and the defrosting is performed. Driving frequently. The count is accumulated by the counting means, and when the count reaches a certain number within the predetermined time of the clock, the operation control unit stops the operation of the compressor 1 and performs the heater alone operation, so that the durability of the device is improved. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a heat pump water heater in one embodiment of the present invention.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Refrigerant-water heat exchanger 4 Decompression device 5 Check valve 6 Evaporator 7 Hot water storage tank 8 Circulation pump 9 Heater 10 Refrigerant temperature detector 11 Operation recognition unit 12 Evaporation temperature control unit 13 Defrost control Unit 14 dead zone control unit 15 clock 16 counting means 17 operation control unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 29/00 361-371 F25B 30/02 F25B 47/02

Claims (4)

(57) [Claims] 1. A compressor, a four-way valve, a refrigerant-to-water heat exchanger, a pressure reducing device, an evaporator, and the evaporator and the compressor are connected to the four-way valve.
A coolant circulation circuit for supplying sequentially refrigerant connected via the pressure
In parallel with the compressor, the four-way valve, the evaporator, and the pressure reducing device
Check valve provided, refrigerant to water heat exchanger, refrigerant to water heat
Exchanger and compressor are connected via the four-way valve and refrigerant
A defrost circuit for flowing water, a lower part of the hot water tank , a circulation pump, the refrigerant-to-water heat exchanger, a heater, the heater and the hot water tank
A hot water supply circuit for supplying sequentially water by connecting upper, the evaporator inlet
The refrigerant temperature of the outlet is detected, and the refrigerant is recirculated from the refrigerant circuit.
A refrigerant temperature detector for transmitting a plurality of signals (set temperature) for switching to a medium defrosting circuit, an operation recognition unit for recognizing the compressor alone operation or a combined operation of the compressor and the heater, and the operation recognition unit A heat pump water heater comprising an evaporation temperature control unit for switching a set temperature of the refrigerant temperature detector by a signal of ( i ), and lowering the set temperature of the refrigerant temperature detector during the combined operation with respect to the compressor alone operation. 2. A four-way valve is switched by a signal from a refrigerant temperature detector.
And a defrost control unit that controls the circulation pump and the heater, and receives the first signal of the refrigerant temperature detector.
By switching the refrigerant defrosting circuit, stops the energization of the circulation pump and the heater, said after receiving the first signal, said receiving a second signal of the first signal from the high temperature signal
2. The heat pump water heater according to claim 1, further comprising: switching to the refrigerant circuit again , energizing the circulation pump, and energizing the heater with a delay. 3. Detection of a first signal of a refrigerant temperature detector for switching to the refrigerant defrosting circuit is detected once at the first time after the start of the boiling operation by the refrigerant circulation circuit , and thereafter for a certain period of time. 2. The heat pump water heater according to claim 1, further comprising a dead zone control section provided with a dead zone time in which a dead zone is not detected. 4. A clock counting means for accumulating the number of times of reception of the first signal <br/> refrigerant temperature detector for switching the refrigerant defrosting circuit, said counting means in a predetermined clocking time of the clock When a certain number of times is reached, the operation of the compressor is stopped.
The heat pump water heater according to claim 1, further comprising an operation control unit that switches the operation to the heater alone operation .