JP2003161544A - Heat pump type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump type water heater that prolongs service life of a compressor by reducing an operational stress on the compressor and prevents occurrence of a 'hot water outage' phenomenon. <P>SOLUTION: The heat pump type water heater comprises a heat pump unit 2 and a tank unit 1 having a hot water storage tank 3 for storing warm water heated up in the heat pump unit 2. As the frequency of the compressor 25 in the heat pump unit 2, an upper limit value lower than a normally required frequency is set. In a midnight time period, an antistress operation is executed with a frequency lower than the upper limit value. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Generally, a heat pump type hot water supply apparatus includes a tank unit 71 having a hot water storage tank 70 and a heat source unit 73 having a refrigerant circuit 72, as shown in FIG. Further, the refrigerant circuit 72 is configured by connecting a compressor 74, a water heat exchanger 75, an expansion valve 77 and an evaporator 78 in this order. The tank unit 71 includes the hot water storage tank 70 and a circulation path 79, and a water circulation pump 80 and a heat exchange path 81 are provided in the circulation path 79.
In this case, the heat exchange passage 81 is composed of the water heat exchanger 75.

In the above apparatus, when the compressor 74 is driven and the pump 80 is driven (operated), stored water (hot water) flows out from the intake port provided at the bottom of the hot water storage tank 70 into the circulation path 79, This flows through the heat exchange passage 81.
At this time, this hot water is heated (boiling up) by the water heat exchanger 75 and returned to the upper part of the hot water storage tank 70 from the hot water inlet. As a result, high-temperature hot water is stored in the hot water storage tank 70.

[0004]

By the way, since the current electricity rate system is set so that the electricity rate unit price in the middle of the night is lower than that in the daytime, this operation is performed at a low price in the middle of the night (e.g., 23:00). There is an increasing number of cases in which the running cost is reduced during the period from 7:00 to 7:00). However, if hot water of a predetermined capacity is to be obtained within a short time such as the midnight time as described above, operation with high capacity is unavoidable, and therefore the compressor 74 is so-called by continuing high capacity operation. Driving stress,
The life of the compressor 74 was shortened.

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object thereof is to reduce the operating stress of the compressor and to extend the life of the compressor. It is an object of the present invention to provide a heat pump type hot water supply device capable of preventing the occurrence of the "out of hot water" phenomenon (a phenomenon in which the hot water in the hot water tank runs out).

[0006]

Therefore, the heat pump type hot water supply apparatus according to claim 1 comprises a heat pump unit 2 and a tank unit 1 having a hot water storage tank 3 for storing the hot water boiled by the heat pump unit 2. The heat pump type hot water supply device is characterized by performing stress prevention operation in which the frequency of the compressor 25 of the heat pump unit 2 is lower than the rated frequency during the midnight time.

In the heat pump type hot water supply apparatus according to claim 1,
During the midnight time, the stress prevention operation is performed with the compressor 25 of the heat pump unit 2 at a frequency lower than the rated frequency, so that the operation stress of the compressor 25 can be reduced.

The heat pump hot water supply apparatus according to the second aspect is characterized in that, in the stress prevention operation, the fan air volume of the evaporator 28 of the heat pump unit 2 is made lower than the rated air volume.

In the heat pump type hot water supply apparatus according to the second aspect, since the fan air volume is also reduced, the operation stress of the fan 34 can be reduced.

A heat pump type hot water supply apparatus according to a third aspect of the present invention includes a heat pump unit 2 and the heat pump unit 2
In a heat pump type hot water supply apparatus provided with a tank unit 1 having a hot water storage tank 3 for storing the hot water boiled in, a frequency of the compressor 25 of the heat pump unit 2 is set to an upper limit value lower than a frequency usually required. The feature is that during the midnight time period, the stress prevention operation is performed at a frequency lower than the upper limit value.

In the heat pump hot water supply apparatus according to the third aspect of the present invention, the frequency of the compressor 25 is set to an upper limit value that is lower than the normally required frequency, and the compressor is driven at a frequency lower than this upper limit value. As a result, the operating stress of the compressor 25 can be reliably reduced as compared with the normal time.

In the heat pump hot water supply apparatus according to the present invention, the fan air flow rate of the evaporator of the heat pump unit is set to an upper limit value lower than the fan air flow rate normally required, and the upper limit value is set in the stress prevention operation. It is characterized by having a lower fan air flow rate.

In the heat pump type hot water supply apparatus according to the fourth aspect, the fan air volume of the evaporator 28 is set to an upper limit value lower than the normally required fan air volume, and the fan 34 is driven with a fan air volume lower than the upper limit value. As a result, the driving stress of the fan 34 can be reliably reduced as compared with the normal time.

The heat pump hot water supply apparatus according to claim 5 detects the amount of hot water stored in the hot water storage tank 3 at the end of the midnight time, and when the amount of hot water storage is less than the necessary amount, the heat pump hot water supply device is operated during the daytime outside the midnight time. The heat pump unit 2 performs a boiling operation to supplement the shortage of the hot water storage tank 3.

In the heat pump hot water supply apparatus according to the fifth aspect, when the amount of hot water stored in the hot water storage tank 3 at the end of the midnight time is less than the required amount, the boiling operation by the heat pump unit 2 is performed during the daytime outside the midnight time. It is possible to prevent the so-called "run-out" of hot water in the hot water storage tank 3 which is lost during use.

In the heat pump type hot water supply apparatus according to the sixth aspect of the present invention, the frequency of the compressor 25 during the stress prevention operation is determined based on the hot water storage amount at the start of the midnight time zone so that the required hot water quantity is heated in the midnight time zone. It is characterized by that.

In the heat pump type hot water supply device according to the sixth aspect, the required amount of hot water can be boiled in the midnight time period, and the daytime operation in which the unit price of electric power is high can be avoided.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Next, specific embodiments of the heat pump type hot water supply apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a simplified diagram of this heat pump type hot water supply apparatus. This heat pump type hot water supply apparatus includes a tank unit 1 and a heat pump unit (heat source unit) 2, and heats water (hot water) in the tank unit 1 with the heat source unit 2. To do.

The tank unit 1 includes a hot water storage tank 3,
The hot water stored in the hot water storage tank 3 is supplied to a bath or the like (not shown). That is, the hot water storage tank 3 is provided with a water supply port 5 on its bottom wall and a hot water outlet 6 on its upper wall. Then, city water is supplied from the water supply port 5 to the hot water storage tank 3, and high-temperature hot water is discharged from the discharge port 6. Further, in the hot water storage tank 3, a water intake 10 is opened in the bottom wall thereof, and a hot water inlet 11 is opened in the upper part of the side wall (peripheral wall), so that the hot water intake 10 and the hot water inlet 11 are connected by a circulation path 12. Has been done. A water circulation pump 13 and a heat exchange passage 14 are provided in the circulation passage 12. A water supply channel 8 is connected to the water supply port 5.

By the way, in the hot water storage tank 3, five remaining hot water amount detectors 18a, 18b, 18 are arranged at a predetermined pitch in the vertical direction.
c, 18d, and 18e are provided. Each of the remaining hot water amount detectors 18a ... Is composed of, for example, a thermistor.

Next, the heat pump unit (heat source unit) 2 is provided with a refrigerant circuit, and this refrigerant circuit includes a compressor 25.
A water heat exchanger 26 constituting the heat exchange passage 14, an electric expansion valve (pressure reducing mechanism) 27, and an air heat exchanger (evaporator) 28.
It is configured by connecting and in order. That is, the discharge pipe 29 of the compressor 25 is connected to the water heat exchanger 26, and the water heat exchanger 26
To the electric expansion valve 27 via a refrigerant passage 30, the electric expansion valve 27 to an evaporator 28 via a refrigerant passage 31, and the evaporator 28 and the compressor 25 with an accumulator 32 interposed therebetween. It is connected through the passage 33. As a result, when the compressor 25 is driven, the water heat exchanger 26 moves to the heat exchange passage 14
The water flowing through can be heated. Also, the evaporator 28
A fan 34 for adjusting the capacity of the evaporator 28 is attached to the.

By the way, as shown in FIG. 2, the control unit of this heat pump type hot water supply system has the above-mentioned remaining hot water amount detector 18
a residual hot water amount detecting means 46 composed of a, 18b, 18c, 18d, and 18e, a setting means 48 described later, and a control means 47 to which data (numerical value) from the detecting means 46 and the setting means 48 are input. Prepare That is, the data from the remaining hot water amount detectors 18a, 18b, 18c, 18d, 18e and the like are input to the control means 47, and the control means 47 adjusts the frequency of the compressor 25 and the fan air volume of the fan 34 of the evaporator 28. To do. The control means 47 can be configured using, for example, a microcomputer.

According to the heat pump type hot water supply apparatus constructed as described above, when the compressor 25 is driven and the water circulation pump 13 is driven (operated), the hot water storage tank 3
The stored water (warm water) flows out from the water intake 10 provided at the bottom of the circulation passage 12 of the circulation passage 12. At this time, this hot water is heated (boiling up) by the water heat exchanger 14 and returned from the hot water inlet 11 to the upper part of the hot water storage tank 3. By continuously performing such an operation, high temperature hot water can be stored in the hot water storage tank 3. This operation is performed in the midnight (midnight) time zone (for example, 8 hours from 23:00 to 7:00) in which the unit price of electric power is set to be lower than that in the daytime. At this time, it is preferable to perform the stress prevention operation in which the compressor 25 is driven at a frequency lower than the rated frequency (normally required frequency) in the midnight time. The stress prevention operation is the compressor 2
This is a driving that can avoid driving with high performance of No. 5 and suppress the occurrence of driving stress.

For this stress prevention operation, the compressor 2
An upper limit value (a frequency lower than the normally required frequency) is determined (set) for the operating frequency of 5, and an upper limit value (the rotational speed of the fan motor) of the fan 34 (the rotational speed of the fan motor is higher than the normally required rotational speed). Low speed) is determined (set) and operation is performed so that these upper limits are not exceeded. At this time, there are the following first, second and third operation methods. The first operating method is to set the compressor 2 in advance by the setting means 48 shown in FIG.
In this method, the frequency of 5 and the rotation speed of the fan 34 are set in advance, and the control means 47 controls the operation based on these values. In the second operation method, the upper limit of the frequency of the compressor 25 and the upper limit of the rotation speed of the fan 34 are determined based on the remaining hot water amount (the remaining hot water amount at the start of the midnight time) detected by the remaining hot water amount detecting means 46. This is a method in which the value is determined and the control means 47 controls the vehicle based on these values to operate. Further, in the third operation method, the frequency of the compressor 25 and the rotation speed of the fan 34 are set in advance, and the midnight time is performed based on the settings, and the residual hot water amount at the end of the midnight time is detected by the hot water amount detecting means. This is a method of detecting at 46, calculating the operating time in the daytime other than the midnight time zone based on the remaining hot water amount, and performing the operation of boiling up to the required amount in the daytime.

First, the first operating method will be described with reference to the flowchart of FIG. In step S1, it is determined whether the normal operation (rated operation) or the stress prevention operation is performed. In this case, a normal operation (rated operation) or a stress prevention operation is performed by a remote controller (not shown) attached to this heat pump hot water supply device The user can set whether to perform it or not. When the stress prevention operation is not performed, that is, when the normal operation is performed, the process proceeds to steps S2 and S3. That is, in step S2,
The preset upper limit of the operating frequency of the compressor 25 is canceled, and in step S3, the preset upper limit of the air volume of the fan 34 is canceled. As a result, the compressor 25 is driven at a normal frequency, and the fan 34 is driven so as to have a normal air volume.

In the case of this normal operation (rated operation), a normal boiling operation (operation with rated capacity) is performed so that the required amount of hot water is boiled up at the end of the midnight time zone as shown in FIG. . That is, when the operation is performed at the rated capacity, the time required for the required amount of hot water to boil is calculated, and the peak shift time is set according to this time. Then, the operation is started by shifting the peak shift time from the start of the midnight time zone, and the operation is ended at the end of the midnight time zone. Therefore, the peak shift time in FIG. 4 is the time from the midnight time zone start time to the actual boiling start time, and is changed depending on the amount of hot water to be boiled, the ability, and the like.

If it is determined in step S1 that the stress prevention operation is to be performed, the process proceeds to steps S4 and S5. That is, the compressor 25 is driven at a frequency lower than the upper limit value of the set frequency (for example, around 60 Hz), and the fan 34 is driven with the upper limit value of the set fan rotation speed (for example, around 500 rpm). Drive so that the air volume is lower than that. As a result, the compressor 2
It is possible to reduce the driving stress generated in the fan 5 and the fan 34. Even in the case of this stress prevention operation, it is preferable that the entire amount be boiled at the end of the midnight time period. That is, when this stress-preventing operation is performed, the operating time during which the required amount of hot water can be heated is calculated, and the peak shift time is set according to this operating time.
Then, the operation is started by shifting the peak shift time from the start of the midnight time zone, and the operation is ended at the end of the midnight time zone.

As described above, when the stress prevention operation is performed, the occurrence of the operation stress of the compressor 25 can be suppressed, and the durability of the compressor 25 can be improved.
Moreover, the noise is lower than the drive noise that is normally generated, and the quiet operation can be performed. This allows the user (user) to have a comfortable life in the midnight time without being bothered by noise.

Next, the second operation method will be described with reference to the flow chart shown in FIG. First, in step S6, it is determined whether it is the midnight time zone start time. That is, whether or not it is 23:00 is determined by a time measuring means (clock) not shown. And if it is not the midnight time zone start time,
Maintain the same state until the midnight time zone start time,
If it is the midnight time zone start time, the process proceeds to step S7, and it is determined whether to perform the normal operation (rated operation) or the stress prevention operation as in step S1. If stress-preventing driving is not performed, perform normal driving during the midnight hours.

When the stress prevention operation is performed, the process proceeds to step S8, and the amount of heat stored in the hot water storage tank 3 is confirmed. That is, the remaining hot water amount detecting means 46 detects the remaining hot water amount in the hot water storage tank 3 to calculate the tank heat storage amount. Next, the process proceeds to step S9, and the required capacity is calculated. In this case, the required capacity is calculated by subtracting the tank heat storage amount from the tank heat capacity (heat capacity of the required amount of hot water) and dividing by the midnight time. Then, the process proceeds to step S10, and the upper limit values (the upper limit value of the frequency of the compressor 1 and the upper limit value of the air volume of the fan 34) corresponding to the required capacity are set. By setting in this way, as shown in FIG. 6, the stress prevention operation is started from the beginning of the midnight time zone (23:00), and the necessary amount (total amount) of the stress prevention operation is completed at the end of the midnight time zone (7:00). Allow boiling to complete.

Further, in step S7, when the normal operation is performed without performing the stress prevention operation,
(Because hot water may remain in the hot water storage tank 3,)
The remaining hot water amount is detected at the start of the midnight time, and the hot water amount obtained by subtracting this remaining hot water amount from the required hot water amount is used as the boiling water amount. The operation may be shifted by the peak shift time from the start of the time zone.

Also by this second operation method, the required amount of hot water can be stored in the hot water storage tank 3 at the end time of the midnight time, and the hot water used can be prevented from running out. Moreover, the frequency of the compressor 25 is lower than the frequency normally used, and the fan 34
Since the fan air volume is lower than the fan air volume that is normally used, the compressor 25 and the fan 34 can reduce operational stress, and have excellent durability as a heat pump type hot water supply device. The noise is lower than that of the driving sound, and quiet driving can be performed.

Next, the third operating method will be described with reference to the flow chart shown in FIG. In this case, steps S11 to S15 are equivalent to steps S1 to S5 shown in FIG. That is, in the midnight time period, the stress prevention driving may or may not be performed. Then, in step S16, it is determined whether or not the midnight time period has ended.

If the midnight time zone has not ended, the process returns to step S11. If the midnight time zone has ended, the process proceeds to step S17, the tank heat storage amount is detected, and the process proceeds to step S18. In this step S18, it is determined whether or not boiling (heating) of the hot water storage tank 3 is necessary in the daytime other than the midnight time. That is, it is determined whether (user required heat amount-tank heat storage amount) / capability> 0.
Here, the amount of heat required by the user is the amount of heat required for hot water.

If this relational expression is not satisfied in step S18, the hot water storage tank 3 has the required heat quantity, and therefore the process proceeds to step S19, and the daytime reheating time is set to "0" and the boiling operation is performed. To finish. Further, if this relational expression is established in step S18, it means that it does not have the necessary amount of heat, so the process proceeds to step S20, and this shortage reheating time is calculated (calculated). This reheating time can be obtained from (user required heat amount-tank heat storage amount) / capacity. Then, reheating is performed in the daytime only for the calculated time. At this time, the required time may be a rated capacity operation or a stress prevention operation. That is, the daytime operation may be the rated operation or the stress prevention operation. In stress-preventing operation, the operating time is longer than in normal operation (rated operation). It should be noted that it is possible to determine whether or not (user required heat amount-tank heat storage amount)> 0 in step S18.

According to this third operation method, during the midnight time, either normal operation or stress-preventing operation may be carried out. If the heating operation can be avoided and the required amount of hot water cannot be secured at this midnight time, as shown in FIG. 8, the additional heating operation will be performed in the daytime. Therefore, during the midnight time, the stress prevention operation can reduce the operation stress of the compressor 25 and the fan 34, and
Low noise can be achieved. Moreover, when the required amount of hot water cannot be secured by only the midnight operation, the additional heating can be performed in the daytime to supplement the shortfall.

By the way, when the stress prevention operation is performed,
In the above embodiment, the fan air volume is also reduced, but as another embodiment, only the frequency of the compressor 25 may be reduced. Even in this case, the operation stress of the compressor 25 can be reduced and stable operation can be performed. Moreover, it is possible to drive quietly during this midnight time.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications can be carried out within the scope of the present invention. For example, the upper limit value of the compressor 25 and the upper limit value of the fan 34 that are set in advance can be arbitrarily set according to the desired boiling time, the required amount of hot water, and the like. In each of the flowcharts of FIGS. 3, 5, and 7, the stress prevention operation is set to be performed or not to be performed, but the stress prevention operation is always performed in the midnight time zone. You may set it. Further, in the midnight time period, it is possible to perform an operation in which only the fan air volume is reduced without lowering the frequency of the compressor 25, thereby reducing the operating stress of the fan 34 and reducing noise. Can also be achieved. Also, FIG. 3 and FIG.
In the operation method shown in (1), it is premised that the required amount of hot water is equal to or smaller than the capacity of the hot water storage tank 3, but even in these operations, the required amount of hot water is lower than the capacity of the hot water storage tank 3. Many may be set. In this case, steps S17, S18, S19 and S2 of FIG.
Each step of 0 may be added.

[0039]

According to the heat pump type hot water supply device of the first aspect, the operation stress of the compressor can be reduced. As a result, the durability of the compressor can be improved, and stable operation can be performed for a long period of time.

According to the heat pump type hot water supply device of the second aspect, it is possible to reduce the operating stress of the fan. As a result, the heat pump hot water supply apparatus as a whole has excellent durability.

According to the heat pump type hot water supply device of the third aspect, the operating stress of the compressor can be reliably reduced as compared with the normal time. As a result, the durability of the compressor can be surely improved, and stable operation can be performed for a long period of time.

According to the heat pump type hot water supply device of the fourth aspect, the operating stress of the fan can be reliably reduced as compared with the normal time. As a result, the heat pump hot water supply apparatus as a whole has excellent durability.

According to the heat pump type hot water supply device of the fifth aspect, it is possible to reliably prevent "runout of water" which is lost during use of the hot water in the hot water storage tank. As a result, the user can use the hot water with peace of mind and can spend comfortably.

According to the heat pump type hot water supply device of claim 6, the required amount of hot water can be boiled in the midnight time, the daytime operation with a high unit price of electric power can be avoided, and the running cost can be reduced. .

[Brief description of drawings]

FIG. 1 is a simplified diagram showing an embodiment of a heat pump type hot water supply apparatus of the present invention.

FIG. 2 is a simplified block diagram of a control unit of the heat pump water heater.

FIG. 3 is a flowchart showing a stress prevention operation of the heat pump type hot water supply device.

FIG. 4 is a simplified diagram showing an operating time of a boiling operation of the heat pump type hot water supply device.

FIG. 5 is a flowchart showing another stress prevention operation of the heat pump type hot water supply device.

FIG. 6 is a simplified diagram showing an operation time of another boiling operation of the heat pump hot water supply device.

FIG. 7 is a flowchart showing another stress prevention operation of the heat pump type hot water supply device.

FIG. 8 is a simplified diagram showing an operation time of another boiling operation of the heat pump type hot water supply device.

FIG. 9 is a simplified view of a conventional heat pump type hot water supply device.

[Explanation of symbols]

1 tank unit 2 heat pump unit 3 hot water storage tank 25 compressor 28 Evaporator

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takao Aizawa             2 of 1000 Otani, Okamoto-cho, Kusatsu-shi, Shiga             Daikin Industries, Ltd. Shiga Works

Claims (6)

[Claims] 1. A heat pump type hot water supply apparatus comprising: a heat pump unit (2); and a tank unit (1) having a hot water storage tank (3) for storing hot water boiled by the heat pump unit (2). In the time zone, the compressor (2) of the heat pump unit (2) is
The heat pump type hot water supply device is characterized by performing stress prevention operation in which 5) is set to a frequency lower than the rated frequency. 2. The stress prevention operation according to claim 1, wherein the fan air volume of the evaporator (28) of the heat pump unit (2) is made lower than the rated air volume.
Heat pump water heater. 3. A heat pump type hot water supply device comprising a heat pump unit (2) and a tank unit (1) having a hot water storage tank (3) for storing the hot water boiled by the heat pump unit (2). Set an upper limit value lower than the normally required frequency to the frequency of the compressor (25) of the unit (2), and perform stress prevention operation at a frequency lower than this upper limit value in the midnight time zone. A heat pump type hot water supply device. 4. The fan air flow rate of the evaporator (28) of the heat pump unit (2) is set to an upper limit value that is lower than the fan air flow rate normally required, and in the stress prevention operation, the fan air flow rate is higher than this upper limit value. The heat pump type hot water supply apparatus according to claim 3, wherein the fan air volume is low. 5. The amount of hot water stored in the hot water storage tank (3) at the end of the midnight time is detected, and when the hot water storage amount is smaller than the required hot water amount, the heat pump unit (2) is used during the daytime outside the midnight time. The heat pump type hot water supply apparatus according to any one of claims 1 to 4, wherein a boiling operation is performed to supplement the shortage of the hot water storage tank (3). 6. The frequency of the compressor (25) during the stress prevention operation is determined based on the amount of hot water stored at the start of the midnight time period so that the required hot water amount is heated in the midnight time period. The heat pump water heater according to any one of claims 1 to 5.