JPH06300358A - Hot water storage type electric warm water machine - Google Patents

Abstract

PURPOSE:To reduce in size a hot water storage type electric warm water machine for storing hot water from an upper part of a hot water reservoir, to perform energy conservation and to stabilize a hot water temperature. CONSTITUTION:The hot water storage type electric warm water machine comprises a hot water supply circuit having a hot water reservoir 1, a low flow rate valve 2, a high flow rate switching valve 3 provided in parallel with the valve 2, a circulating pump 4 and a heater 5, a first temperature sensor 7 provided at an upstream side of the heater 5, a second temperature sensor 8 provided at a downstream side of the heater 5, and a controller 11 for controlling the valve 3 according to signals of the sensors 7, 8 and the pump 4. When a hot water mixing layer area of the reservoir 1 is heated, the water is fed to the valve 2 when the water temperature is a predetermined temperature or lower, the valve 3 is opened when it reaches the predetermined temperature to increase an operating range thereby to store high temperature hot water in the entire reservoir 1, thereby reducing in size the reservoi6 1. At the time of supplying hot water during operating, the valve 3 is closed by the controller 11 according to the signal of the sensor 7, thereby stabilizing the hot water temperature.

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 electric water heater in which a heater is separated from a hot water storage tank and hot water is stored from the upper part of the hot water storage tank.

[0002]

2. Description of the Related Art Conventionally, this kind of hot water storage type electric water heater is shown in FIG.
As shown in FIG. 1, it comprises a hot water storage tank 1, a circulation pump 4, a heater 5, a temperature detector 8 and a controller 11. And the heater 5
Signal from a temperature detector 8 provided downstream of the circulation pump 4
The hot water heated to a predetermined temperature is stored from the upper part of the hot water storage tank 1 by controlling the flow rate of or the output of the heater 5 by the control unit 11.

[0003]

However, in the conventional structure as described above, a hot and cold water mixed layer is generated at a portion where the hot water and the hot water are in contact with each other in the hot water storage tank, and the layer expands. To go. Therefore, when the boiling is completed, the temperature of the water flowing into the heater gradually rises. Therefore, when the output of the heater is constant, the temperature detector so that the temperature downstream of the heater is constant,
It is necessary to increase the flow rate of the circulation pump by the action of the control unit. For example, if the output of the heater is constant at 4.4 kW, a flow rate of 0.9 L / min is required when the initial feed water temperature of 15 ° C. is heated to 85 ° C. Then, near the completion of boiling, a flow rate of 4.2 L / min is required when the inflow temperature of the heater inlet of 70 ° C. is heated to 85 ° C.

Further, assuming that the initial feed water temperature difference is about 20 deg throughout the year, the flow width is 0.79 to 4.2 L / min.
And wide range. If a circulation pump with a small flow rate adjustment range is used, it becomes impossible to store high-temperature water to the lower part of the hot water storage tank. Therefore, the amount of high-temperature hot water that can be used is reduced, so that hot water runs out and it becomes necessary to enlarge the hot water storage tank in order to prevent it. And
If the hot water storage tank is made larger, the heat radiation loss from the hot water storage tank increases when the hot water supply load is small (for example, in summer, on days when there is no bathing), which is a problem from the viewpoint of energy saving. In addition, there are problems in terms of equipment transportation surface and installation space.

Further, when the circulation pump is operated at a high flow rate near the completion of boiling, if the low temperature water is supplied from the lower part of the hot water tank while the circulation pump is operating at a high flow rate, the temperature at the outlet of the heater becomes constant. In order to maintain it, it becomes necessary to control the circulation pump to a low flow rate in a short time.

Further, since the hot water storage tank and the heater are separated, they are installed with various connecting pipe lengths. Therefore, the characteristics of the flow rate and the lift of the circulation pump vary depending on the length of the connecting pipe. If the circulation pump is designed with a short pipe length, if the circulation pump is used with a long pipe length, the circulation pump will rotate at a high speed, which causes a problem in reliability of the device. On the other hand, when the circulation pump is designed with a long pipe length, if it is used with a short pipe length, the equipment will be overinvested.

The first object of the present invention is to solve the above problems and to promote the stabilization of the hot water temperature. The second object is to further reduce the size of the equipment, save energy and stabilize the hot water temperature.
The purpose of.

[0008]

In order to achieve the above object, the present invention provides a hot water storage tank, a low flow rate valve, a high flow rate opening / closing valve provided in parallel with the low flow rate valve, a circulation pump, and a heater with a built-in heater. Water supply circuit in which heaters are sequentially connected, a first temperature detector provided upstream of the heater, a second temperature detector provided downstream of the heater, the first temperature detector and the second temperature The control unit controls the outputs of the circulation pump and the heater and the high flow rate on-off valve by a signal from a detector.

A hot water storage tank, a low flow rate valve, a high flow rate on-off valve provided in parallel with the low flow rate valve, a circulation pump, a hot water supply circuit in which a heater with a built-in heater is sequentially connected, and a downstream side of the heater. A temperature detector, a drive voltage detection means for the circulation pump, a flow rate detection means provided in a hot water supply pipe or a hot water discharge pipe of the hot water storage tank, and a drive voltage for the circulation pump controlled by a signal from the temperature detector. The control unit controls the high flow rate on-off valve by a signal from the drive voltage detection unit and a signal from the flow rate detection unit.

[0010]

The present invention has the following features. (1) When the temperature of water flowing into the heater is lower than a predetermined temperature, a low flow valve having a large flow resistance is flown to reach the predetermined temperature. Then, a signal is sent to the control unit to open the high flow rate on-off valve. Therefore, if the initial feed water temperature is low and a low flow rate is required, operate the circulation pump at a low flow rate and a high lift, and if the high flow rate is required in the hot and cold water mixed layer region, open and close the high flow rate on-off valve. A high flow rate can be secured by reducing the loss resistance of the open hot water supply circuit. Further, when low temperature water is supplied to the hot water storage tank during boiling operation, the first temperature detector detects the signal, and the signal is output to the high flow rate on-off valve via the control unit. Close it. Therefore, since the circulation circuit has a low flow rate in a short time, the outlet temperature of the heater becomes stable.

(2) Further, in a system in which the connecting pipe lengths of the hot water storage tank and the heater are variously different, when the initial supply water temperature is low, the driving voltage is low and the hot water / water mixing layer region is reached. The operation is performed by increasing the drive voltage. Then, when the drive voltage of the circulation pump becomes higher than a predetermined voltage, the high flow rate on-off valve is opened via the control unit by a signal from the drive voltage detection means. Therefore, the load on the circulation pump is reduced and a high flow rate can be secured. Then, when the drive voltage of the circulation pump reaches the predetermined voltage again, the operation of the heater of the heater and the circulation pump is stopped.
Therefore, the circulation pump is not operated at a voltage higher than the predetermined voltage, and the reliability of the device is ensured. Also, during boiling operation, when low-temperature water is supplied to the hot water storage tank by hot water, it is detected by the flow rate detecting means, and the signal is closed via the control unit to close the high flow rate on-off valve. To Therefore, since the circulation circuit has a low flow rate in a short time, the outlet temperature of the heater becomes stable.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to.

In FIG. 1, 1 is a hot water storage tank, 2 is a low flow valve, and 3 is a high flow opening / closing valve, which are provided in parallel with the low flow valve 2. Reference numeral 4 is a circulation pump, 5 is a heater, and a heater 6 is incorporated therein. The lower part of the hot water storage tank 1, the low flow valve 2, the high flow opening / closing valve 3, the circulation pump 4, the heater 5, and the upper part of the hot water storage tank 1 are sequentially connected to form a hot water supply circuit. . A first temperature detector 7 detects an upstream temperature of the heater 5. A second temperature detector 8 detects the downstream temperature of the heater 5.

In FIG. 2, 9 is a circulating pump drive voltage detecting means, and 10 is a flow rate detecting means, which are provided in the water supply pipe 12 or the hot water discharge pipe 13 of the hot water storage tank 1. A control unit 11 controls the drive voltage of the circulation pump 4 or the input of the heater 6 by the signal of the second temperature detector 8, and the high flow on-off valve 3 by the signal of the flow rate detecting unit 10. To control.

In the above structure, the low temperature water in the lower part of the hot water storage tank 1 flows into the heater 5 through the low flow rate valve 2 by the action of the circulation pump 4, and is heated by the heater 6 there. . Then, the heated high-temperature water flows into the upper part of the hot water storage tank 1 and is gradually stored from the upper part. In that case, the second temperature detector 8 detects the outlet temperature of the heater 5, sends a signal to the control unit 11 so as to reach a predetermined temperature, and outputs the drive voltage of the circulation pump 4 or the output of the heater 6. To control. As a result, hot water having a predetermined temperature is gradually stored from the upper portion of the hot water storage tank 1.

When the entire hot water storage tank 1 has been boiled and the completion of boiling has been reached after the operation time has elapsed, the water in the hot and cold water mixed layer starts to flow from the lower portion of the hot water storage tank 1 from the hot water storage tank 1. As the outlet temperature of the heater 5 rises accordingly, the second temperature detector 8 detects the rise in temperature and sends a signal to the controller 11 to increase the drive voltage of the circulation pump 4 to increase the flow rate. Is controlled so as to reach a predetermined temperature. Then, the first temperature detector 7 detects that the low-temperature water having a predetermined temperature starts to flow from the hot water storage tank 1, and the control unit 1
1 is sent to open the high flow rate on-off valve 3. Therefore, the circulation system loss resistance of the hot water supply circuit becomes small,
Even at the same flow rate, the drive voltage of the circulation pump 4 drops. Further, even if the temperature of the water flowing out from the lower part of the hot water storage tank 1 further rises, the drive voltage of the circulation pump 4 can be increased, and the operating range is expanded. Therefore, hot water can be stored even in the lower part of the hot water storage tank 1.

When hot water is discharged during the boiling operation, low temperature water flows into the hot water storage tank 1 and the temperature detected by the first temperature detector 7 decreases. Then, the signal is sent to the control unit 11 to close the high flow rate on-off valve 3. Therefore, the circulation pump 4 has a low flow rate, and the heater 5
The outlet temperature of is stable in a short time.

Next, the case where the hot water storage tank 1 and the heater 5 are separated and the connection pipe length can be freely set will be described. The case of boiling the initial feed water temperature is the same as described above. Then, when the low-temperature water in the hot-water mixed layer region starts to flow from the lower part of the hot-water storage tank 1, the second temperature detector 8 changes the driving voltage of the circulation pump 4 so that the outlet temperature of the heater 5 becomes constant. A signal to increase is sent to the control unit 11. After that, the circulation pump drive voltage detection means 9 detects that the drive voltage of the circulation pump 4 has reached a predetermined voltage, sends the signal to the control unit 11, and opens the high flow rate on-off valve 3. . Therefore, since the loss resistance of the circulation system of the hot water supply circuit is reduced, the drive voltage of the circulation pump 4 is reduced even at the same flow rate.

When the temperature of the water flowing out from the hot water storage tank 1 further rises, the drive voltage of the circulation pump 4 increases again to operate up to a predetermined voltage. Therefore, the operating range is expanded, and hot water is stored even in the lower part of the hot water storage tank 1.
Further, when the length of the connecting pipe is long, the loss resistance of the circulation system becomes large. Therefore, in the above process, only the low flow rate valve 2 is switched to the high flow rate on-off valve 3 at an early stage. When the high-flow rate on-off valve 3 is in the open state and the drive voltage of the circulation pump 4 reaches a predetermined voltage, a signal is sent to the control unit 11 to turn off the heater 6 and the circulation pump 4. To do. Therefore, the circulation pump 4 is not operated at a predetermined voltage or higher, and the reliability of the equipment is ensured.

When hot water is discharged during the boiling operation, it is detected by the flow rate detecting means 10, and the signal is sent to the control section 11 to close the high flow rate on-off valve 3. Therefore, the circulation pump 4 has a low flow rate, and the outlet temperature of the heater 5 becomes stable in a short time. FIG. 3 shows the operation of the circulation pump 4. A solid line A in FIG. 3 shows the loss resistance when flowing through the low flow rate valve 2, and a solid line B shows the loss resistance when flowing through the high flow rate on-off valve 3. The point C is the operating point of the circulation pump 4 up to the hot water mixing layer, the points C to D are the operating points of the circulation pump 4 in the hot water mixing layer region, and the points D to E are the high points. The operating point when switching to the flow rate on-off valve 3 is shown. Then, the circulation pump 4 at the point F
It becomes possible to operate up to the maximum driving voltage of.
Therefore, high-temperature hot water can be stored in the whole hot water storage tank 1, and the size and energy saving of the device can be reduced.
In addition, the stabilization of the hot water temperature and the reliability of the equipment are improved.

[0021]

As described in the above embodiments, the electric water heater of the present invention includes a hot water storage tank, a low flow rate valve, a high flow rate on-off valve provided in parallel with the low flow rate valve, a circulation pump, and a built-in heater. Hot water supply circuit in which the heaters are sequentially connected, a first temperature detector provided upstream of the heater, a second temperature detector provided downstream of the heater, a first temperature detector, and a second temperature When low temperature water in the hot and cold water mixing layer region flows from the hot water storage tank due to the provision of a control unit that controls the high flow rate on-off valve by a signal from a detector and a circulation pump, and a high flow rate is required, A signal is sent from the first temperature detector to the control unit to open the high flow rate on-off valve, so that the loss resistance of the circulation system of the hot water supply circuit is reduced and the operating range can be expanded. When hot water is produced during the boiling operation, a signal is sent from the first temperature detector to the control unit to close the high flow rate on-off valve to operate at a low flow rate to stabilize the hot water temperature. Be peeled off. Therefore, the hot water can be stored in the entire hot water storage tank, and the downsizing of the equipment, the energy saving, and the stabilization of the hot water temperature can be achieved.

In addition, in the system in which the hot water storage tank and the heater are connected by a long pipe, in addition to the above structure, a drive voltage detection means of the circulation pump and a flow rate detection means provided in the water supply pipe or the hot water discharge pipe of the hot water storage tank are provided. As a result, when the circulating pump drive voltage detecting means reaches a predetermined voltage, a signal is sent to the control unit to open the high flow rate on-off valve to reduce the loss resistance of the hot water supply circuit and reduce the drive voltage of the circulating pump to operate. Then, the circulation pump can be operated again up to a predetermined voltage.

When hot water is generated during operation, a signal from the flow rate detecting means is sent to the control section to close the high flow rate on-off valve to operate at low flow rate to stabilize the hot water temperature. .
Therefore, the circulation pump 4 is not operated at a predetermined voltage or higher, and the reliability of the equipment is ensured. In addition, the hot water temperature can be stabilized.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of an electric water heater according to another embodiment of the present invention.

FIG. 3 is a change diagram of operating points of a circulation pump according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional electric water heater.

[Explanation of symbols]

 1 Hot Water Tank 2 Low Flow Valve 3 High Flow Open / Close Valve 4 Circulation Pump 5 Heater 6 Heater 7 First Temperature Detector 8 Second Temperature Detector 9 Circulation Pump Drive Voltage Detection Means 10 Flow Rate Detection Means 11 Control Section 12 Water Supply Tube 13 Dehydration tube

Claims (2)

[Claims] 1. A hot water supply circuit in which a hot water storage tank, a low flow rate valve, a high flow rate on-off valve provided in parallel with the low flow rate valve, a circulation pump, and a heater with a built-in heater are sequentially connected, and an upstream of the heater. A first temperature detector provided in the first heater, a second temperature detector provided downstream of the heater, and signals of the first temperature detector and the second temperature detector to input the circulation pump and the heater. A hot water storage type electric water heater comprising a control unit for controlling the high flow rate on-off valve. 2. A hot water storage tank, a low flow rate valve, a high flow rate on-off valve provided in parallel with the low flow rate valve, a circulation pump, a hot water supply circuit in which a heater with a built-in heater is sequentially connected, and a downstream side of the heater. A temperature detector provided in the temperature sensor, a drive voltage detection means for the circulation pump, a flow rate detection means provided for a hot water supply pipe or a hot water discharge pipe of the hot water tank, and a drive voltage for the circulation pump controlled by a signal from the temperature detector. In addition, the hot water storage type electric water heater comprising a control unit for controlling the high flow rate on-off valve with a signal from the drive voltage detection unit and a signal from the flow rate detection unit.