JPH06294547A - Heat pump water heater - Google Patents

Abstract

PURPOSE:To achieve higher operation efficiency by securing the controllability of the temperature in the inflow of hot water into a hot water storage tank and the reliability of the apparatus. CONSTITUTION:A second hot water delivery circuit 16 is provided to a hot water delivery circuit 10 bypassing an auxiliary heater 9 through a solenoid valve 17 from an outlet of a heat exchanger 2 for hot water and a controller 18 is provided to close the solenoid valve 17 in the operation combining a heat pump and the auxiliary heater 9 and in the operation using the auxiliary heater 9 singly and to open it 17 in the operation using the heat pump singly. A control is performed as follow; the solenoid valve 17 is opened in the heat pump-oriented operation to run hot water to the second hot water delivery circuit 16 and when the temperature detected of a water temperature detector 11 rises to reach a first set value, the heat pump is stopped. The solenoid valve 17 is closed while the auxiliary heater 9 is turned ON and a switching is made over to the heat pump-oriented operation as the temperature detected of the water temperature detector 11 lowers with the delivery of hot water or the like while the solenoid valve 17 is opened.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Heretofore, a heat pump water heater of this type has a known structure as shown in Japanese Patent Laid-Open No. 164157/1985. The configuration will be described below with reference to FIGS.

As shown in the figure, a heat pump cycle is constituted by connecting a compressor 1, a heat exchanger 2 for hot water, a throttle mechanism 3, an evaporator 4 and an accumulator 5 with an annular refrigerant pipe line.

In addition, a hot water storage tank 6 is provided from a lowermost portion of the hot water storage tank 6 to a hot water heat exchanger 2 via a pump 7 and an auxiliary heater 9 downstream of the hot water heat exchanger 2. The heat pump cycle and the hot water storage tank 6 are connected by the hot water discharge circuit 10 leading to.

Reference numeral 11 denotes a water temperature detector for detecting the water temperature in the water supply circuit 8, which has a first set value of low temperature and a second set value of high temperature.
It has a set value, a signal for stopping the operation of the heat pump is issued by the first set value, and a signal for stopping the operation of the auxiliary heater 9 is issued by the second set value. Reference numeral 12 denotes a hot water temperature detector that flows into the hot water storage tank 6, which controls the rotation speed of the pump 7 to control the amount of circulating water.
The hot water inflow temperature into the hot water storage tank 6 during the operation is kept constant, and hot water is sequentially stored from the upper portion of the hot water storage tank 6. Reference numeral 13 is a blower, 14 is a water supply pipe provided in the hot water storage tank 6, and 15 is a hot water supply pipe.

The operation of the above structure will be described. When the detected temperature of the water temperature detector 11 is equal to or lower than the first set value at the time of high outside temperature, the auxiliary heater 9 does not operate and the hot water temperature detector 12 operates independently of the heat pump. Thus, hot water having a constant temperature is sequentially stored from the upper part of the hot water storage tank 6. A temperature boundary layer is formed between the warm water stored at this time and the low temperature water in the lower part of the hot water storage tank 6, and when this boundary layer reaches the water supply circuit 8, the temperature detected by the water temperature detector 11 becomes equal to or higher than the first set value. The heat pump operation is stopped and the auxiliary heater 9 is operated. After that, when the temperature detected by the water temperature detector 11 reaches the second set value, the auxiliary heater 9 is stopped. When there is residual hot water in the hot water storage tank 6, the time required for the temperature boundary layer to reach the water supply circuit 8 is shortened, so that the heat pump operation time is short and the operation of the auxiliary heater 9 is long.

When the outside temperature is low, the heat pump and the auxiliary heater 9 are simultaneously operated, and when the temperature detected by the water temperature detector 11 exceeds the first set value, the heat pump operation is stopped and the temperature detected by the water temperature detector 11 is changed. When the second set value is reached, the auxiliary heater 9 is stopped. As a result, a uniform high-temperature hot water is secured to the bottom of the hot water storage tank 6.

[0008]

However, according to the above-mentioned conventional structure, as shown in FIG. 4, during the operation of the heat pump, the temperature boundary layer in the hot water storage tank 6 reaches the water supply circuit 8 to cause the water temperature detector 11 to operate. When the detected temperature of 1 becomes equal to or higher than the first set value T ₁ , the heat pump operation is stopped and the auxiliary heater 9 is operated. At this time, if hot water is supplied from the hot water supply pipe 15, the water supply pipe 14
Since the cold water flows into the hot water storage tank 6 from the above, the temperature detected by the water temperature detector 11 becomes the first set value T ₁ or less, and the auxiliary heater 9 turns O.
Although the FF is performed and the heat pump operation is started, since the heat capacity of the auxiliary heater 9 and the rise of the heat pump is slow and the rise of the hot water temperature from the hot water heat exchanger 2 is slow, the hot water temperature detector 12 detects the hot water temperature Tout. Repeat hunting.

Therefore, there are problems that the flow rate fluctuation of the pump 7 becomes large and it becomes difficult to control the temperature of the hot water flowing into the hot water tank 6 to be constant, and the reliability of the pump 7 is lowered.

The present invention is intended to solve the above problems, and it is an object of the present invention to ensure controllability of the temperature of hot water flowing into a hot water tank and reliability of the apparatus.

[0011]

In order to achieve the above object, the present invention is provided with a second hot water circuit which bypasses an auxiliary heater from a hot water heat exchanger outlet via an electromagnetic valve to reach a hot water circuit. The operation of the heat pump depending on the temperature detected by the detector,
Stop, run the auxiliary heater, stop, heat pump,
The solenoid valve is closed during the auxiliary heater combined operation and the auxiliary heater alone operation, and the solenoid valve is opened during the heat pump independent operation.

[0012]

According to the present invention, with the above construction, when the heat pump is in operation, the electromagnetic valve is opened to allow hot water to flow into the second hot water circuit, the temperature boundary layer in the hot water tank reaches the water supply circuit, and the temperature detected by the water temperature detector rises. When the first set value is reached, the heat pump is stopped, the solenoid valve is closed, and the auxiliary heater is turned on.
However, when the temperature detected by the water temperature detector falls due to hot water, etc., the heat capacity of the auxiliary heater and the temperature of the hot water discharged from the hot water heat exchanger when the heat pump rises are increased by opening the solenoid valve at the same time as switching to heat pump operation. Hunting of the hot water temperature caused by the delay is prevented, and hot water of a constant temperature is caused to flow into the hot water storage tank.

[0013]

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

In FIG. 1, the same reference numerals as those in FIG. 3 denote the same members and have the same functions, and therefore detailed description thereof will be omitted, and different points will be mainly described.

In FIG. 1, reference numeral 16 is a second hot water circuit from the outlet of the hot water heat exchanger 2 to the first hot water circuit 10 between the auxiliary heater 9 and the hot water temperature detector 12 via the solenoid valve 17, and 18 is the water temperature. The detector 11 and the hot water temperature detector 12 are controllers that control the auxiliary heater 9, the pump 7, and the compressor 1 by signals from the detectors.

The operation of the above configuration will be described based on the control flow of FIG. First, the heat pump independent operation will be described. When the device is turned on (S1) in FIG. 2, the pump 7 is turned on (S2), the compressor 1 is turned on (S3), and the solenoid valve 17 is opened (S4).

As a result, the water in the hot water storage tank 6 is pumped by the pump 7 through the water supply circuit 8 to the hot water heat exchanger 2 by the heat of condensation of the heat pump, and the hot water is heated to the second hot water circuit 16 and the first hot water circuit. It stores sequentially from the upper part of the hot water storage tank 6 via 10.
Hot water does not flow to the auxiliary heater 9. Here, the hot water temperature detector 12 detects the hot water temperature Tout at the outlet of the hot water heat exchanger 2 (S5), and controls the rotation speed of the pump 7 so that Tout becomes equal to the set value TA (S6, S7). . Then detect the temperature T of the water supply circuit 8 at a water temperature detector 11 (S8), if the first set value T _1> T continues to control the pump 7, if T ₁ <T conversely hot water storage It is judged that the temperature boundary layer in the tank 6 has reached the water supply circuit 8 (S9), and the compressor 1 is turned off.
FF is performed (S10), the heat pump operation is stopped, the solenoid valve 17 is closed, and the flow of hot water from the second hot water circuit to the auxiliary heater 9 side is changed (S11). Next, the auxiliary heater 9
Is turned on (S12), the hot water temperature detector 12 detects the hot water temperature Tout at the outlet of the auxiliary heater 9 (S13), and the rotation speed of the pump 7 is controlled so that Tout becomes equal to the set value TA (S14). , S15).

Next, the water temperature T of the water supply circuit 8 is detected by the water temperature detector 11.
Is detected (S16), the second set value T ₂And compare T
(S17). T₂<If T, equalize to the bottom of the hot water tank 6.
It is determined that the temperature has risen to 1, and the auxiliary heater 9 is turned off (S1
8) The pump 7 is turned off (S19).

On the contrary, if T ₂ > T, the first set value T ₁ >
If it is T (S20), if T ₁ <T, return to S13 and continue control of the pump 7. If hot water is discharged from the hot water supply pipe 15, T ₁ > T, so the auxiliary heater 9 is turned off. (S21), the process returns to S3 to start the heat pump operation.
Further, when the heat pump and the auxiliary heater 9 are simultaneously operated, the conventional hot water temperature control is performed with the solenoid valve 17 always closed. The above operation is performed by the controller 18.

According to the structure of this embodiment, when the heat pump is in operation, the electromagnetic valve 17 is opened to allow hot water to flow through the second hot water outlet circuit 16, and the temperature boundary layer in the hot water storage tank 6 reaches the water supply circuit 8 to detect the water temperature. When the temperature detected by the water heater 11 rises and reaches the first set value, the heat pump is stopped, the electromagnetic valve 17 is closed, the auxiliary heater 9 is turned on, and the water temperature detector 11 lowers the temperature detected by hot water or the like. Then, by switching to the heat pump operation and opening the solenoid valve 17 at the same time, the flow of hot water to the auxiliary heater 9 is stopped, the heat capacity of the auxiliary heater 9 and the hot water temperature from the hot water heat exchanger 2 when the heat pump starts up. It is possible to prevent hunting of the hot water outlet temperature caused by a slow rise and to allow hot water of a constant temperature to flow into the hot water storage tank 6, and the reliability of the pump 7 is also improved. Further, since the warm water is not supplied to the auxiliary heater 9 during the operation of the heat pump, the heat radiation from the auxiliary heater 9 is reduced and the operation efficiency is improved.

[0021]

As described in the above embodiments, the heat pump hot water supply apparatus of the present invention is provided with the second hot water supply circuit which bypasses the auxiliary heater from the outlet of the hot water heat exchanger through the electromagnetic valve to reach the hot water supply circuit. The heat pump is operated and stopped, and the auxiliary heater is operated and stopped according to the temperature detected by the water temperature detector. Provide a controller that closes the solenoid valve when the heat pump and auxiliary heater are operating together and when the auxiliary heater is operating independently, and opens the solenoid valve when operating the heat pump independently, and opens the solenoid valve when operating the heat pump to make the second hot water. Pour hot water through the circuit.

When the temperature boundary layer in the hot water storage tank reaches the water supply circuit and the temperature detected by the water temperature detector rises to reach the first set value, the heat pump is stopped, the solenoid valve is closed and the auxiliary heater is activated. Is turned on, the temperature detected by the water temperature detector decreases due to tapping water, etc., and control is performed to switch to heat pump operation and at the same time open the solenoid valve.

Thus, the heat capacity of the auxiliary heater at the time of switching from the auxiliary heater operation to the heat pump operation and hunting of the hot water temperature caused by the slow rise of the temperature of the hot water discharged from the hot water heat exchanger are prevented, and the hot water tank The hot water of a constant temperature can be flowed into the inside, and the reliability of the pump is also improved. Further, when the heat pump is in operation, hot water is not supplied to the auxiliary heater, so that heat radiation from the auxiliary heater is reduced and the operation efficiency is improved.

[Brief description of drawings]

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

FIG. 2 is a control flow chart of the embodiment.

FIG. 3 is a circuit configuration diagram of a conventional heat pump water heater.

FIG. 4 is a characteristic diagram showing the relationship between time, water temperature, and water flow rate.

[Explanation of symbols]

 1 Compressor 2 Heat Exchanger for Hot Water 3 Throttling Mechanism 4 Evaporator 6 Hot Water Tank 7 Pump 8 Water Supply Circuit 9 Auxiliary Heater 10 First Hot Water Circuit (Hot Water Circuit) 11 Water Temperature Detector 12 Hot Water Temperature Detector 16 Second Hot Water Circuit 17 Solenoid valve 18 Controller

Claims (1)

[Claims] 1. A heat pump comprising a compressor, a heat exchanger for hot water, a throttling mechanism, and an evaporator connected by an annular refrigerant pipe, and water supplied from the bottom of the hot water storage tank to the heat exchanger for hot water via the pump. Circuit, a water temperature detector in the water supply circuit, an auxiliary heater downstream of the hot water heat exchanger, a first hot water circuit from the auxiliary heater outlet to the top of the hot water tank, and the hot water heat exchanger A second hot water circuit that bypasses the auxiliary heater from the outlet to the first hot water circuit via the solenoid valve, and a hot water temperature detector and a controller are further provided in the first hot water circuit, and the controller is the water temperature detector. Depending on the detected temperature of the heat pump operation, stop,
A heat pump water heater that controls the operation of the auxiliary heater by operating and stopping it, closing the solenoid valve during combined operation of the heat pump and auxiliary heater, and during independent operation of the auxiliary heater, and opening the solenoid valve during independent operation of the heat pump. .