JPH06288644A - Heat pump water heater - Google Patents

Abstract

PURPOSE:To secure controllability of the temperature in the inflow of hot water to a hot water storage tank and reliability of the apparatus in a hot water storage type heat pump water heater. CONSTITUTION:A first hot water temperature detector 17 is provided on a first hot water delivery circuit 16 to an auxilary heater 9 from a heat exchanger 2 for hot water and a second hot water temperature detector 19 on a second hot water delivery circuit 18 to the upper most part of a hot water storage tank 6 from an outlet of the auxilary heater 9. A controller 20 is provided to allow selective use of the first hot water temperature detector 17 in a single heat pump oriented operation and the second hot water temperature detector 19 in the operation combining a heat pump and the auxiliary heater 9 and in the operation using a single auxilary heater 9. The temperature detected of a water temperature detector 11 connected to the lower part of the hot water storage tank 6 rises and a heat pump is stopped when it reaches a first set value, the auxiliary heater 9 is turned ON while the temperature of the hot water is controlled with the second hot water temperature detector 19. Then, the temperature detected with the hot water temperature detector 11 lowers attributed to the delivery of hot water or the like and operation is switched to a heat pump operation while the temperature of the hot water is controlled with the first hot water temperature detector 17.

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 configuration will be described.
When the temperature detected by the water temperature detector 11 is equal to or lower than the first set value at high outside air temperature, the auxiliary heater 9 does not operate, and the hot water temperature detector 12 sequentially stores hot water at a constant temperature from the upper part of the hot water storage tank 6 by the heat pump independent operation. . Hot water stored at this time and hot water storage tank 6
A temperature boundary layer is formed between the lower temperature water and the low temperature water, and this boundary layer reaches the water supply circuit 8, and when 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 driven. 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 temperature boundary layer is the water supply circuit 8
Therefore, the heat pump operating 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, when hot water is discharged from the hot water supply pipe 15, the water supply pipe 1
Since cold water flows into the hot water storage tank 6 from 4, the water temperature detector 11
When the detected temperature of the auxiliary heater 9 becomes lower than the first set value T ₁ and the auxiliary heater 9 is turned off and the heat pump operation is started, the heat capacity of the auxiliary heater 9 and the temperature of the hot water discharged from the hot water heat exchanger 2 are slow. Since the rise is slow, the hot water temperature Tout detected by the hot water temperature detector 12 repeats hunting. Therefore, the flow rate fluctuation of the pump 8 becomes large, and it becomes difficult to control the hot water inflow temperature into the hot water storage tank 6 to be constant, and there is a problem that the reliability of the pump 7 is lowered.

The present invention has been made to solve the above problems, and an object of the present invention is to ensure the controllability of the hot water inflow temperature into the hot water storage tank and the reliability of the apparatus.

[0010]

In order to achieve the above object, the present invention provides a first hot water temperature detector in the first hot water circuit from the downstream side of the heat exchanger for hot water to the auxiliary heater, and the auxiliary heating. A second hot water temperature detector is provided in the second hot water outlet circuit from the outlet of the equipment to the top of the hot water tank, and the
A controller for selectively using the second hot water temperature detector is provided when the hot water temperature detector, the heat pump, and the auxiliary heater are operated together and when the auxiliary heater is operated independently.

[0011]

With the above-described structure, the first hot water temperature detector controls the hot water temperature during operation of the heat pump, 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 auxiliary heater is turned on, the second hot water temperature detector controls the hot water temperature, and the detected temperature of the water temperature detector decreases due to hot water, etc. At the same time, by controlling the hot water temperature with the first hot water temperature detector, the hunting of the hot water temperature caused by the heat capacity of the auxiliary heater and the rise of the hot water temperature from the hot water heat exchanger at the time of rising of the heat pump is prevented, Pour hot water at a constant temperature into the hot water storage tank.

[0012]

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, so that detailed description thereof will be omitted and different points will be mainly described.

In FIG. 1, 16 is a first hot water outlet circuit from the hot water heat exchanger outlet to the auxiliary heater 9 inlet, and 17 is the same circuit 16.
It is the 1st warm water temperature detector provided inside. Reference numeral 18 is a second hot water outlet circuit from the outlet of the auxiliary heater 9 to the upper portion of the hot water storage tank 6, and 19 is a second hot water temperature detector provided in the same circuit 18. 20
Is a controller that controls the auxiliary heater 9, the pump 7, and the compressor 1 as will be described later in accordance with signals from the water temperature detector 11, the first and second hot water temperature detectors 17 and 19.

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, first the pump 7 is turned on (S2) and the compressor 1 is turned on.
(S3).

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 is sequentially stored from the upper portion of the hot water storage tank 6. Here, the first hot water temperature detector 17 detects the hot water temperature Tout at the outlet of the hot water heat exchanger 2 (S4), and controls the rotation speed of the pump 7 so that Tout becomes equal to the set value TA. (S5, S6) Next, the water temperature detector 11 detects the water temperature T of the water supply circuit 8 (S7). If the first set value T ₁ > T, the control of the pump 7 is continued, and conversely T ₁ < If it is T, it is determined that the temperature boundary layer in the hot water storage tank 6 has reached the water supply circuit 8 (S8), the compressor 1 is turned off (S9), and the heat pump operation is stopped. At the same time, the hot water temperature detection is changed from the first hot water temperature detector 17 to the second hot water temperature detector 19 (S1).
0), the auxiliary heater 9 is turned on (S11), the second hot water temperature detector 19 detects the hot water temperature Tout at the outlet of the auxiliary heater 9 (S12), and pumps Tout to be equal to the set value TA. The rotation speed of 7 is controlled (S13, S14).

Next, the water temperature T of the water supply circuit 8 is detected by the water temperature detector 11.
Is detected (S15), the second set value T ₂And compare T.
(S16) T₂<If T, it is even to the bottom of the hot water tank 6.
The auxiliary heater 9 is turned off (S1
7), the pump 7 is turned off (S18).

On the contrary, if T ₂ > T, the first set value T ₁ >
If it is T (S9), if T ₁ <T, return to S12 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. (S
20), at the same time, the second hot water temperature detector 19 detects the hot water temperature.
To the first hot water temperature detector 17 (S21), and the process returns to S3 to start the heat pump operation. When the heat pump and the auxiliary heater 9 are simultaneously operated, the conventional hot water temperature control is performed only by the second hot water temperature detector 19. The above operation is performed by the controller 20.

According to the construction of this embodiment, during the operation of the heat pump, the hot water temperature is controlled by the first hot water temperature detector 17, the temperature boundary layer in the hot water tank 6 reaches the water supply circuit 8, and the water temperature detector 11 Detected temperature rises and the first set value T
_{When the} temperature reaches ₁ , the heat pump is stopped, the auxiliary heater 9 is turned on, the second hot water temperature detector 19 controls the hot water temperature, and the detected temperature of the water temperature detector 11 decreases due to tapping water and the heat pump operation is switched to. At the same time, the first hot water temperature detector 17 controls the hot water temperature. This prevents hunting of the hot water temperature caused by the heat capacity of the auxiliary heater 9 and the temperature of the hot water discharged from the hot water heat exchanger 2 at startup of the heat pump being slow, and allows hot water of a constant temperature to flow into the hot water tank 6. The pump reliability is also improved.

[0020]

As described in the above embodiments, the heat pump hot water supply apparatus of the present invention has the first temperature detector and the auxiliary heating device in the first hot water circuit from the downstream side of the heat exchanger for hot water to the auxiliary heating device. A second hot water temperature detector is installed in the second hot water circuit from the outlet to the top of the hot water storage tank. When the heat pump is operating independently, the first hot water temperature detector, heat pump, and auxiliary heater are operating together and the auxiliary heater is operating independently. A controller that selectively uses the second hot water detector is provided when
Hot water temperature control is performed by the hot water temperature detector, the temperature boundary layer in the hot water tank reaches the water supply circuit, the temperature detected by the water temperature detector rises, and when the first set value is reached, the heat pump is stopped and auxiliary heating is performed. When the water temperature is controlled by the second hot water temperature detector and the hot water temperature is controlled by the second hot water temperature detector, the temperature detected by the water temperature detector drops and the heat pump operation is switched to the first hot water temperature detector.
The hot water temperature is controlled by the hot water temperature detector.

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 discharge temperature caused by the slow rise of the hot water temperature from the hot water heat exchanger are prevented, and the hot water storage tank The hot water of a constant temperature can be flowed into the inside, and the reliability of the pump is also 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 FIG.

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 11 Water Temperature Detector 16 1st Hot Water Circuit 17 1st Hot Water Temperature Detector 18 2nd Hot Water Circuit 19 19th 2 Hot water temperature detector 20 Controller

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display area F24H 4/00

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, a first hot water circuit from the downstream side of the heat exchanger for hot water to an auxiliary heater, a first hot water temperature detector in the first hot water circuit, and the auxiliary heater A second hot water outlet circuit from the outlet to the top of the hot water storage tank;
A second hot water temperature detector and a controller are further provided in the tap water circuit, and the controller controls the operation and stop of the heat pump and the operation and stop of the auxiliary heater according to the temperature detected by the water temperature detector. (1) A heat pump hot water supply device that performs control to selectively use the second hot water temperature detector when operating together with the hot water temperature detector, the heat pump, and the auxiliary heater and during the auxiliary heater alone operation.