JP2002364915A - Solar thermal water-heater provided with stop valve in hot-water storage-tank bypass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar thermal water-heater, in which a stop valve of a large opening area is not necessary, and the hot water can be supplied safely, even if the stop valve is in trouble. SOLUTION: The solar thermal water-heater 1 is provided with a hot-water- storage tank 4, a hot-water and water mixer 5, temperature sensors 14, 7 and a controller 6. The tank 4 sores the hot water produced by heat-exchanging the water supplied from a supply-water pipe 13 with solar heat. The mixer 5 mixes at an optional rate hot-water from the tank 4 and water of a branch pipe 13b branched from the pipe 13. The sensors 14, 7 detect respectively hot-water temperature of the tank 4 and the temperature of hot water downstream of the mixer 5. The controller 6 controls operation of the above installations. In the branch pipe 13b, another branch pipe 13c is provided for connecting with a bypass the inlet part of the tank 4 and downstream side of the outlet of the tank 4. A stop valve 16 is placed on the way of the pipe 13c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a solar water heater.

[0002]

2. Description of the Related Art FIG. 4 shows one of conventional solar water heaters. The hot water in the hot water storage tank 4 warmed via the heat medium heated by solar heat is supplied to a hot water mixing device 5 controlled by the control unit 6.
Is diluted with water so as to reach a desired hot water supply temperature, and then supplied. A temperature sensor 7 and a shutoff valve (closed type when not energized) 15 are provided in the middle of the piping downstream of the hot and cold water mixing device 5, and when the temperature sensor 7 detects hot water exceeding the desired hot water supply temperature, the shutoff valve 15 is turned on. It is a closed structure. Further, when the hot water mixing device 5 fails in the hot water storage tank side open state, the closing valve 15 is closed to prevent hot water supply.

[0003]

However, when the shut-off valve is provided downstream of the hot and cold water mixing apparatus as described above, the opening area is large (that is, the pressure loss is low) in order to compensate for the decrease in the hot water supply amount due to the pressure loss of the shut-off valve itself. (Small) shut-off valves must be employed. Also, if the shut-off valve (closed when not energized) fails, the hot water passage itself will be closed,
No water can be supplied from the solar water heater. The present invention provides a solar water heater that eliminates such difficulties, that is, a solar water heater that does not require a shutoff valve having a large opening area and that can safely supply hot water even if the shutoff valve fails. .

[0004]

In order to achieve the above object, in the present invention, apart from a branch pipe from a water supply pipe to a hot water mixing apparatus, a water supply inlet side of a hot water storage tank and a downstream side of a hot water outlet of a hot water storage tank are provided. If another shut-off valve is placed in the middle of this, a hot-water supply can be stopped even if the hot-water mixing device fails while the hot-water storage tank hot side is open, or if the shut-off valve itself fails. The inventors came to realize that the risk of overheating and hot water could be reduced without any problem, and completed the present invention.

That is, the present invention provides a hot water storage tank 4 for storing hot water that has been heated by exchanging heat with the solar heat (water supplied from the water supply pipe 13), A hot and cold water mixing device 5 capable of mixing water from the branched branch pipe 13b at an arbitrary ratio; and a temperature sensor 14 for detecting the hot water temperature (Th) of the hot water storage tank 4 and the hot water temperature downstream of the hot water mixing device 5; 7 and a control unit 6 for controlling these operations. The solar water heater 1 includes a branch pipe 13b that bypasses a water supply inlet side of the hot water storage tank 4 and a downstream side of the hot water outlet of the hot water storage tank 4. The solar water heater 1 is provided with another branch pipe 13c to be connected and a shutoff valve 16 in the middle of the branch pipe 13c.

Here, the shut-off valve 16 provided in the middle of the branch pipe 13c does not need to be a shut-off valve having a large opening area (ie, a small pressure loss) because it is not in the main path of hot water supply. Therefore, the opening area is small and the cost can be relatively low. Further, the shut-off valve may be an open type when not energized or a closed type when not energized. Further, the downstream connection portion of the branch pipe 13c may be on the front side or the rear side (outlet side) of the hot water mixing apparatus 5.

[0007] Regarding the control of the heat collection operation and other operations in the solar water heater 1, when the shut-off valve 16 is operating normally, the temperature (Th) of the hot water stored in the hot water storage tank 4 is equal to a predetermined upper limit temperature T. It is preferable to control so as not to exceed. When the shut-off valve 16 fails, the hot water storage tank 4
The temperature (Th) of the hot water to be stored at T is not to exceed a predetermined temperature (α) lower than T, that is, T-α
It is preferable to control so as to be less than. Here, the upper limit temperature T is about 70 ° C. This is a temperature that can be set arbitrarily. The predetermined temperature (α) is about 10
The temperature is about ° C. That is, T-α is a temperature of about 60 ° C. This is also a temperature that can be set arbitrarily.

Further, it is preferable that the controller 6 has a built-in failure detection circuit for detecting a failure of the shut-off valve 16.

When the control unit 6 detects a failure of the shut-off valve 16, it is preferable that the abnormality is indicated by a display or an alarm buzzer.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a solar water heater according to an example of the present invention. There is a hot water storage tank 4 in the solar water heater 1, and a heat medium (water or antifreeze) heated by a heat collector 10 installed on a roof or the like is in the heat collector 10, the circulation passage, and the heat exchanger 2. The water in the hot water storage tank 4 is indirectly heated by the heat exchanger 2. Here, the temperature of the heated hot water is detected by the temperature sensor 14. Hot water discharged from hot water storage tank 4 is supplied to desired temperature (set temperature: T
R) in the hot and cold water mixing device 5 so that
And the mixture is appropriately diluted with water from the furnace and exits through the mixed hot water outlet 8. The remote control 11 is connected to the control unit 6 via a remote control code 12.

The branch pipe 13b is provided with another branch pipe 13c for bypassing the water supply inlet side of the hot water storage tank 4 and the hot water outlet side of the hot water storage tank 4, and a shut-off valve 16 is disposed in the middle of the branch pipe 13c. I have. Further, the control unit 6 has a built-in failure detection circuit for detecting a failure of the shut-off valve 16, and when the shut-off valve 16 fails, that is, when the shut-off valve stops in the open state or stops in the closed state. In this case, the heat collecting operation is controlled so that the hot water temperature (Th) of the collected hot water storage tank does not exceed a predetermined temperature (α) lower than the temperature T (the upper limit temperature during normal operation).

FIG. 2 shows an example of a shut-off valve failure detecting circuit in the solar water heater according to the present invention. A detection circuit for a shut-off valve failure will be described. However, the shut-off valve should be closed when not energized,
The power supply for the shut-off valve is DC 90 V full-wave rectification. Relay RL
When the contact 1 is closed, power is directly applied to both ends of the shut-off valve, a drive current flows, and the shut-off valve changes from “closed” to “open”. As shown, a resistor R1 is connected in parallel with the relay contact RL1.
Is connected to the photocoupler PC1, the relay contact RL1 is open and the power supply current is R
1, PC1 and the shut-off valve 16, and this electric current
, And the signal propagates as an electric signal to the control circuit on the secondary side of PC1. Therefore, it can be determined that the closing valve is “normal”. Conversely, if the shut-off valve is disconnected and is in a failure state, the power supply current does not flow, and there is no electric signal from the PC 1, so that the stop valve can be determined to be “failed”. In order for this circuit to operate normally, the current flowing through PC1 must be sufficiently smaller than the drive current required for the closing valve to open from "closed".
Is a condition.

This will be described more specifically. Assuming that the shut-off valve (closed type when not energized) 16 is normal, the hot water temperature (Th) of the hot water storage tank 4 is set to the upper limit (T) 70 for normal operation.
° C and the remote control setting hot water temperature (TR) is 42 ° C, the shut-off valve (closed when not energized) 16 is closed, and the hot water in the hot water storage tank is not diluted with water from the branch pipe 13c. The hot and cold water is mixed by the hot and cold water mixing device 5 to the set temperature of the remote controller, and the hot water temperature is adjusted. The opening degree of the mixing valve of the hot water mixing device (mixing valve) 5 is adjusted and controlled by the control unit 6 through the detection of the hot water temperature of the temperature sensor 7 provided downstream of the hot water mixing device 5.

When the hot water mixing device 5 fails in the hot water storage tank hot water side open state, the high temperature hot water of the upper limit (T) 70 ° C. in the hot water storage tank 4 is discharged without hot water mixing in the hot water mixing device 5. The temperature sensor 7 detects this, energizes the shut-off valve 16 and opens it, and the water flows through the bypass branch pipe 13c.
Reduce the temperature of the hot water by lowering the temperature to ℃. Here, the mixing ratio of hot and cold water is determined by the ratio between the diameter of the pipe at the outlet of the hot water storage tank and the diameter of the bypass pipe. When the mixing ratio of hot water and hot water is 4: 1 and the maximum hot water supply from the hot water supply device is 20 liters per minute, the hot water temperature (Th) of the hot water storage tank is 70 ° C.
If so, the temperature of the hot water drops to about 60 ° C. Hot water at 60 ° C. is usually hot water with a low risk of causing burns. That is, even if the hot water mixing device 5 breaks down with the hot water storage tank hot side open, hot water supply at a temperature exceeding 60 ° C. is avoided beforehand.

If the shut-off valve 16 fails, the "failure detection circuit" detects the malfunction of the shut-off valve 16, limits the upper limit of the heat collecting temperature to 10 ° C. lower to 60 ° C., and supplies hot water at a temperature exceeding 60 ° C. Avoid beforehand. FIG. 3 shows an operation flowchart. The superheated hot water supply is prevented irrespective of the presence or absence of the failure of the hot water mixing device 5.

The amount of sunlight is small, and the hot water temperature (T
h) is the desired hot water supply temperature, that is, the remote control set hot water temperature (T
When the temperature is lower than R), for example, the hot water temperature (Th) is 35 ° C.
In the case where the remote control set hot water temperature (TR) is 42 ° C., the shut-off valve 16 is set to “closed”, and the hot water from the hot water storage tank 4 is not diluted with the water passing through the bypass branch pipe 13c.
In addition, the hot water mixing apparatus 5 supplies hot water at the same hot water temperature without dilution with water. This hot water may be further heated to a desired hot water supply temperature (42 ° C.) using an auxiliary heat source device (such as a gas instantaneous water heater).

When the control unit 6 detects a failure of the shut-off valve 16, the failure may be displayed on the remote controller 11 or the control unit 6, or an alarm (buzzer sound) may be issued. This is because the failure of the shut-off valve can be quickly known and dealt with (repaired).

[0018]

According to the solar water heater of the present invention, a shut-off valve having a large opening area is not required, which is advantageous in terms of cost.
Also, even if the hot and cold water mixing device fails while the hot water storage tank side is open, the hot water from the hot water storage tank can be diluted with water by opening the shutoff valve provided in the other branch pipe route, so High-temperature hot water supply is prevented beforehand. Also, even if the shut-off valve fails, the upper limit of the heat collection temperature of the hot water storage tank is reduced to a safe hot water temperature, thereby preventing hot water supply from the hot water storage tank. Further, when the failure of the shut-off valve is detected and the "abnormality" is notified, the shut-off valve can be repaired promptly.

[Brief description of the drawings]

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

FIG. 2 is an example of a shut-off valve failure detection circuit in the solar water heater of the present invention.

FIG. 3 is an operation flowchart of an example of the solar water heater of the present invention.

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

[Explanation of symbols]

1: solar water heater 2: heat exchanger 3: forced circulation pump 4: hot water storage tank 5: hot and cold water mixing device 6: control unit 7: temperature sensor 8: mixed hot water outlet 9: water inlet 10: heat collector 11: remote control 12 : Remote control code 13: Water supply pipe 13 a: Water supply pipe (to hot water storage tank) 13 b: Branch pipe (to hot water mixing equipment) 13 c: Another branch pipe 14: Temperature sensor 15: Shutoff valve (closed type when not energized) 16: Closed valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference)

Claims (4)

[Claims] 1. A hot water storage tank for storing hot water heated by solar heat, a hot water mixing device capable of mixing hot water from the hot water storage tank and water from a branch pipe branched from a water supply pipe at an arbitrary ratio, and the hot water storage tank A temperature sensor for detecting a hot water temperature (Th) and a hot water temperature downstream of the hot and cold water mixing device, and a control unit for controlling the operation thereof. A solar water heater provided with another branch pipe connecting a water supply inlet side and a downstream side of a hot water outlet of a hot water storage tank by a bypass, and having a shut-off valve in the middle of the branch pipe. 2. When the shut-off valve is operating normally, the temperature (Th) of hot water stored in the hot-water storage tank is controlled so as not to exceed a predetermined upper limit temperature T, and the shut-off valve fails (the shut-off valve closes). 2) The temperature (Th) of the hot water stored in the hot water storage tank is controlled so as not to exceed a predetermined temperature (α) lower than T.
Solar water heater. 3. The solar water heater according to claim 1, wherein the controller includes a failure detection circuit for detecting a failure of the shut-off valve. 4. The solar water heater according to claim 1, wherein when the control unit detects a failure of the shut-off valve, "abnormal" is notified.