JPH08219555A - Direct heat collection type solar heat warm water device - Google Patents

Abstract

PURPOSE: To push up water up to a heat collector even with the use of a water capacity pump by providing a water stop means on a warm water return pipe between a connection portion of a coupling pipe to a warm water return pipe and a hot water return pipe for stopping a water flow or a hot water flow at need. CONSTITUTION: A first solenoid valve 13 is provided on a water feed pipe 10 on the discharge side of a circulation pump 12, and a drainage pipe 14 of the water feed pipe 10 is branched and connected between the first solenoid valve 13 and a heat collector 1 at a location close to the first solenoid valve 13. A second solenoid valve 15 is provided on the drainage pipe 14, and a coupling pipe 16 for connecting a warm water return pipe 11 with the water feed pipe 10 is connected with the water feed pipe 10 between the branch connection portion of the drainage pipe 14 and the first solenoid valve 13. A third solenoid valve 18 is provided on the coupling pipe 16, and a check valve 20 being water stop means is provided on the warm water return pipe 11 between the connection portion of the coupling pipe 16 to the warm water return pipe 11 and a hot water storage tank 8 for stopping a water flow or a hot water flow. Hereby, even a small capacity circulation pump 12 can push up water up to the heat collector 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct heat collecting type solar water heating apparatus for directly supplying water to a heat collector to collect heat and collecting the obtained hot water in a hot water storage tank.

[0002]

2. Description of the Related Art A direct heat collecting type solar water heating apparatus for directly supplying water to a heat collector to collect heat and storing the obtained hot water in a hot water storage tank has a simple structure and can be constructed at low cost.
Many prototypes of this type of solar water heater have been developed before.

In such a direct heat collecting type solar water heater, water freezes in the heat collector at night in winter. Therefore, when the temperature becomes frozen, the drain valve is opened and the water in the heat collector is frozen. It has a structure to discharge.

In addition to such a direct heat collecting type solar water heating apparatus, a heat exchanger is provided in a hot water storage tank, and an antifreeze liquid collecting type solar water heating apparatus circulates an antifreezing liquid between the heat exchanger and the heat collecting apparatus. Is also proposed.

[0005]

However, these two types of solar water heaters have the following problems. Problems of the direct-collection type solar water heater (a) In order to drop the water in the collector just by opening the drain valve, the pipeline must be inclined downward toward the drain valve. However, it is difficult for a contractor to ensure that the piping is made in this manner, and the water drop method is hardly used in mass-produced products. (B) In the water drop method, a pump that produces a pressure that can push water up to the heat collector is required. Therefore, the power consumption of the pump increases and the cost of the pump also increases. (C) Since the water is dropped from the heat collector, the inside of the hot water storage tank is in an unpressurized state, and a hot water pump is required to take out the hot water in the hot water storage tank from the faucet, and the advantage of low cost is lost.

Antifreeze-collecting solar water heater (a) The heat collection method using an antifreeze requires a heat exchanger from antifreeze to water, which increases costs. (B) Due to heat exchange from the antifreeze liquid to water, the heat exchange performance deteriorates. (C) When the antifreeze liquid leaks due to corrosion of the heat exchanger, the antifreeze liquid mixes into the water. (D) In the heat collection method using antifreeze, the heat exchanger is installed in the hot water tank. In such a structure, the temperature of the whole water in the hot water tank gradually increases, so it is hot until evening. Since hot water is not available and solar hot water cannot be used in the morning or afternoon, the efficiency of using the solar water heater is poor.

An object of the present invention is to provide a direct heat collecting type solar water heating apparatus which can solve the problems of the direct heat collecting type. Another object of the present invention is to provide a direct-collection solar water heater that can push up water to a collector even with a small-capacity pump. Another object of the present invention is to provide a direct heat collecting solar water heater that can further reduce costs. Another object of the present invention is to provide a direct-collection solar water heater that can prevent damage to the heat collector due to water pressure.

[0008]

According to the present invention, a heat collector, a hot water storage tank installed below the heat collector, a lower part of the hot water storage tank and a lower part of the heat collector are connected to each other. A water supply pipe for supplying water in the hot water storage tank to the heat collector, and an upper portion of the heat collector and an upper portion of the hot water storage tank are connected to each other to supply hot water generated by the heat collector to the hot water storage tank. An object of the improvement is a direct heat collecting type solar water heating device provided with a hot water return pipe and a circulation pump which is connected to the water supply pipe and sends water in the hot water storage tank to the heat collector.

In the direct heat collecting solar water heating apparatus according to the present invention, a first solenoid valve is provided on the water supply pipe on the discharge side of the circulation pump, and a first solenoid valve is provided between the first solenoid valve and the heat collector. At the position close to the first solenoid valve, a drain pipe is branched and connected to the water pipe, a second solenoid valve is provided in the drain pipe, and a connecting pipe connecting the hot water return pipe to the water pipe is Connected to the water pipe between the branch connection point of the drainage pipe and the first solenoid valve, the connection pipe is provided with a third solenoid valve, and the connection point of the connection pipe to the hot water return pipe and the The hot water return pipe is provided with a water stop means for stopping the flow of water or hot water as needed between the hot water storage tank and the hot water storage tank.

In this case, it is preferable to provide an air vent valve on the upper part of the heat collector. Here, the upper portion of the heat collector includes not only the upper portion of the heat collector itself but also a portion of a hot water return pipe connected to the upper portion of the heat collector.

It is preferable that a water supply pipe is connected to a lower portion of the hot water tank via a pressure reducing valve so that a required water pressure is always applied to the hot water tank. Further, it is preferable that the water supply pipe, the hot water return pipe, and the connection pipe are formed of a flexible plastic pipe. Further, it is preferable that a relief valve for releasing abnormal water pressure acting on the heat collector is provided below the heat collector.

[0012]

As described above, according to the present invention, the water supply pipe is provided with the first solenoid valve on the discharge side of the circulation pump, and the first solenoid valve is provided between the first solenoid valve and the heat collector. At the position of, the drain pipe is branched and connected to the water pipe, a second solenoid valve is provided in the drain pipe, and the connecting pipe connecting the hot water return pipe to the water pipe is connected to the branch connection point of the drain pipe and the first solenoid valve. Between the hot water return pipe and a hot water return pipe between the connection point of the hot water return pipe and the hot water tank. By providing a water stop means for stopping the heat collector, when there is a risk of freezing in the heat collector, the first solenoid valve is closed and the second and third solenoid valves are opened, so that the heat collector and the water pipe And the water in the hot water return pipe can be drained.

In this case, if an air vent valve is provided above the heat collector, it is possible to easily supply water or drain water to the heat collector.

Further, when the required water pressure is constantly applied from the water supply pipe to the hot water storage tank, this water pressure acts as a force to push the water in the hot water storage tank to the heat collector side. It is possible to reduce the capacity of the pump that pumps out, and it is possible to reduce costs. Even if an airlock phenomenon occurs, the air in the hot water return pipe and in the heat collector is released by the water pressure in the hot water storage tank by opening the first and third solenoid valves and closing the second solenoid valve. It can be pushed up and discharged from the air release valve, and the air lock can be eliminated.

If the water supply pipe, the hot water return pipe, and the connecting pipe are formed of a flexible plastic pipe, the pipe can be bent without a seam and no sharp bend is required. Even if there is a point where the slope of the drain is not downgraded in the direction of the drain pipe, if the drain pipe is located at a position lower than the water pipe and hot water return pipe to be drained, these water pipes and hot water The water in the return pipe can be drained.

Further, if a relief valve for releasing abnormal water pressure acting on the heat collector is provided in the lower part of the heat collector, even if the heat collector has a structure vulnerable to water pressure, the heat collector can be protected from water pressure. Can be protected.

[0017]

1 and 2 show an embodiment of a direct heat collecting type solar water heating apparatus according to the present invention. In the direct heat collecting type solar water heating apparatus of the present embodiment, the heat collector 1 is installed so as to be inclined on a roof or the like where solar heat is easily collected. The heat collector 1 is formed by seam-welding the two stainless steel thin plates 2a and 2b around each other in a bag shape, and a plurality of upward water channels 3 are provided side by side in the widthwise direction in an intermediate portion of each. The stainless steel thin plates 2a and 2b are bent and formed in a corrugated shape. The collector main body 4 formed by processing the stainless thin plates 2a and 2b in this way is housed in a case 5 having an open top. A heat insulating material 6 is arranged between the bottom of the case 5 and the collector body 4. Case 5
A transparent plate 7 such as a plastic plate is attached to the opening of the.

A hot water storage tank 8 is provided on the ground or the like below the heat collector 1. The hot water storage tank 8 is housed in a heat insulation container 9. The lower part of the hot water storage tank 8 and the lower part of the heat collector 1 are connected by a water supply pipe 10, whereby the water in the hot water storage tank 8 is supplied to the heat collector 1. Further, the upper part of the heat collector 1 and the upper part of the hot water storage tank 8 are connected by a hot water return pipe 11, whereby the hot water generated by the heat collector 1 is supplied to the hot water storage tank 8. Water pipe 1 adjacent to hot water storage tank 8
A circulation pump 12 is connected to 0 to send the water in the hot water storage tank 8 to the heat collector 1.

A first solenoid valve 13 is provided on the water supply pipe 10 on the discharge side of the circulation pump 12. Further, a drain pipe 14 is branched and connected to the water supply pipe 10 at a position near the first solenoid valve 13 between the first solenoid valve 13 and the heat collector 1, and a second pipe is connected to the drain pipe 14. A solenoid valve 15 is provided. A connecting pipe 16 for connecting the hot water return pipe 11 to the water pipe 10 is connected to the water pipe 10 between the branch connection point 17 of the drain pipe 14 and the first solenoid valve 13. Are provided. Between the connection point 19 of the connecting pipe 16 to the hot water return pipe 11 and the hot water tank 8, the hot water return pipe 11 is provided with a check valve 20 as a water shutoff means for stopping the flow of water or hot water as needed. ing. The check valve 20
The flow of hot water from the heat collector 1 to the hot water storage tank 8 is allowed, but the flow of hot water from the hot water storage tank 8 to the heat collector 1 is not allowed.

The water supply pipe 10, the hot water return pipe 11 and the connecting pipe 16 are formed of a flexible plastic pipe such as a polybutene pipe. The sizes of the water supply pipe 10, the hot water return pipe 11, and the connecting pipe 16 are preferably those having an inner diameter of 13 mm or less.

An air vent valve 21 and a first temperature sensor 22 are provided above the heat collector 1. In this case, the air vent valve 21 is the hot water return pipe 1 located above the heat collector 1.
The first temperature sensor 22 is provided at the folded-back portion 1 and is inserted in the inside of the upper portion of the heat collector 1.

A second temperature sensor 23 is attached to the hot water return pipe 11 between the check valve 20 and the hot water storage tank 8 for detecting the temperature of hot water passing through the hot water return pipe 11. A third temperature sensor 24 is attached to the lower part of the hot water storage tank 8 to detect the water temperature in the hot water storage tank 8. The detection signals from the first, second, and third temperature sensors 22, 23, and 24 are input to the controller 25.
The controller 25 determines the circulation pump 1 based on these detection signals.
A control signal is output to the second, first, second, and third solenoid valves 13, 15, and 18.

The water supply pipe 10 below the heat collector 1 is provided with a relief valve 26 for releasing abnormal water pressure acting on the heat collector 1, and the lower part of the water storage tank 8 is provided in the water storage tank 8. A water supply pipe 28 directly connected to the water supply via an adjustment pressure reducing valve 27 is connected so as to always apply a required water pressure. A hot water outlet pipe 29 is connected to the upper portion of the hot water storage tank 8. The tap pipe 29 is connected to a tap tap 30. An air vent valve 31 and a safety valve 32 are provided above the tap pipe 29.

Next, the operation of such a direct heat collecting type solar water heater will be described. When water is not contained in the heat collector 1, when a water supply command is issued from the controller 25, the first and third solenoid valves 13 and 18 are opened, the second solenoid valve 15 is closed, and hot water is stored. Due to the water pressure in the tank 8, the water in the hot water tank 8 passes through the circulation pump 12 (not yet operating at this time) and the first solenoid valve 13, one through the water supply pipe 10, and the other through the water supply pipe 10. The heat is supplied to the heat collector 1 through the connection pipe 16, the third solenoid valve 18, and the hot water return pipe 11. At this time, the air existing inside the water pipe 10, the connecting pipe 16, the hot water return pipe 11, the heat collector 1, and the like is discharged from the air vent valve 21 by being pushed up by the rise of water.

After one to two minutes, the third solenoid valve 18 is closed by a timer command in the controller 25, and the circulation pump 12 is operated. Thereby, the water in the hot water storage tank 8 enters the heat collector 1 via the water supply pipe 10 via the circulation pump 12 and the first solenoid valve 13, and the water is heated by the solar heat in the heat collector 1 and becomes hot water. Then, it passes through the hot water return pipe 11 and passes through the check valve 20 to enter the upper portion of the hot water storage tank 8. Since the specific gravity of this hot water is low, it accumulates in the upper part of the hot water storage tank 8 in layers without mixing with the water in the lower part.

As described above, the air existing in the water pipe 10, the connecting pipe 16, the hot water return pipe 11, the heat collector 1 and the like escapes from the air vent valve 21 and the water flows into the water pipe 10 and the hot water return pipe 11. After being filled, the circulation pump 12 is operated, and the water pressure applied from the water supply pipe 28 removes the water in the hot water storage tank 8 from the heat collector 1.
Since it works as a force to push it up, the water is circulated even if the pressure of the circulation pump 12 is low. By repeating such water circulation, the water in the hot water storage tank 8 becomes hot water in sequence.

When the temperature detected by the first temperature sensor 22 becomes lower than a predetermined value or when the temperature detected by the first temperature sensor 22 becomes lower than the temperature detected by the second temperature sensor 23, the controller 25 circulates a command. The operation of the pump 12 stops, and the first solenoid valve 13 closes.

When the temperature detected by the first temperature sensor 22 is close to the freezing temperature, for example, 3 ° C. or lower, the controller 25 instructs the second solenoid valve 15 and the third solenoid valve 18 to open, and the air vent valve 21. More air enters the heat collector 1 and the hot water return pipe 11, and the water in the heat collector 1, the water supply pipe 10, the hot water return pipe 11 and the connecting pipe 16 is discharged through the drain pipe 14. In this case, if the water supply pipe 10, the hot water return pipe 11 and the connecting pipe 16 are formed of a relatively thin flexible plastic pipe, for example, a polybutene pipe or the like, there is no joint and no sharp bend, so even if it is thin. Even if there is a place where the flow resistance is small and the slope of these pipes is not necessarily a downward slope in the direction of the drain pipe 14, if the position of the drain pipe 14 is lower than the water supply pipe 10 and the hot water return pipe 11. The water in the heat collector 1, the water supply pipe 10, the hot water return pipe 11 and the connection pipe 16 is discharged through the drain pipe 14 by the so-called siphon principle. At this time, the water pressure in the hot water storage tank 8 is controlled by the first solenoid valve 1.
3 and a check valve 20, a water supply pipe 10 and a hot water return pipe 11
Is cut off and retained. Even if water remains in the water supply pipe 10, the hot water return pipe 11 and the connecting pipe 16, the flexible plastic pipe will not be frozen and damaged.

The heat collector 1 is made of two stainless steel sheets 2
It has been proved that when a and 2b are formed by seam welding, the cross-sectional area of the water channel 3 in the heat collector 1 can be easily expanded and contracted, so that it will not be damaged even if frozen. However, in principle, the heat collector 1 having such a structure that the cross-sectional area of the water channel 3 easily expands and contracts and is unlikely to be frozen and damaged is unavoidably weak against water pressure. Therefore, in order to protect the heat collector 1 from water pressure damage, if a relief valve 26 that keeps the water pressure below the damage water pressure of the heat collector 1 is provided at the bottom of the heat collector 1, generally the heat collector 1 will be installed on the roof. Since it is installed above and the hot water storage tank 8 is installed on the ground, the collector 1
The water pressure exerted on the heat collector 1 is reduced by the difference in height, so that the water pressure exerted on the heat collector 1 can be maintained within a safe range.

During operation of the circulation pump 12, the tap 30
When the hot water is discharged more vigorously, the amount of water supplied to the hot water storage tank 8 from the adjusting pressure reducing valve 27 cannot catch up, and the water pressure in the hot water storage tank 8 decreases, so that the water pressure in the heat collector 1 placed at a high position. May become a negative pressure, and air may enter the heat collector 1 and the hot water return pipe 11 from the air vent valve 21. Therefore, if a circulating pump 12 with a low generated pressure is used, the air in the hot water return pipe 11 may be reduced. It is also possible to use the air vent valve 2 that is trapped inside and pushes air below the warm water return pipe 11 by the pump pressure.
There is a possibility that an air lock phenomenon may occur in which water cannot be discharged from No. 1 and a locked state occurs, causing the circulation of water to stop. In such a case, heat cannot be collected even if there is solar radiation.

Means for avoiding this is provided in the embodiment of FIG. That is, when the airlock phenomenon occurs, heat is not collected even when the circulation pump 12 is operating, so that the temperature of the third temperature sensor 24 is higher than the temperature at which the first temperature sensor 22 starts collecting heat. Will not rise. Therefore, if the state where the difference between the detected temperature of the first temperature sensor 22 and the detected temperature of the third temperature sensor 24 is equal to or higher than a certain level continues for a certain period of time, the controller 25 determines that an air lock has occurred and issues a command. When the operation of the circulation pump 12 is stopped and the first and third solenoid valves 13 and 18 are opened, the air in the hot water return pipe 11 and the air in the heat collector 1 are pushed up by the water pressure in the hot water storage tank 8. Is discharged from the air vent valve 21. In this state, after a lapse of a predetermined time, for example, 1 to 2 minutes, the third solenoid valve 18 is closed again by a command from the controller 25 and the circulating pump 12 is driven. Circulation will begin. If air has not escaped even in this series of operations, the same operation is repeated again by a command from the controller 25.

The check valve 20 can be replaced with a solenoid valve. In this case, the solenoid valve controls its opening / closing by a command from the controller 25.

[0033]

As described above, in the solar water heater of the direct heat collecting type according to the present invention, the first electromagnetic valve is provided in the water pipe at the discharge side of the circulation pump, and the first electromagnetic valve and the heat collector are provided. A drain pipe is branched and connected to a water pipe at a position close to the first solenoid valve, and a second solenoid valve is provided in the drain pipe, and a connecting pipe connecting a hot water return pipe to the water pipe is connected to a drain pipe. And a first solenoid valve connected to the water supply pipe, a third solenoid valve is provided on the connection pipe, and the hot water is connected between the connection point of the connection pipe to the hot water return pipe and the hot water storage tank. Since the return pipe is provided with a water stopping means for stopping the flow of water or hot water as needed, when there is a risk of freezing in the heat collector, the first solenoid valve is closed and the second and third solenoid valves are closed. , The water in the heat collector, the water supply pipe and the hot water return pipe can be drained.

In particular, according to the second aspect of the present invention, since the air vent valve is provided on the upper part of the heat collector, it is possible to easily supply and drain water to the heat collector.

According to the third aspect of the present invention, a required water pressure is constantly applied from the water supply pipe into the hot water tank.
The water pressure can be used to supply water to the heat collector, the capacity of the pump can be reduced, and the cost can be reduced. Even if an airlock phenomenon occurs, the air in the hot water return pipe and in the heat collector is released by the water pressure in the hot water storage tank by opening the first and third solenoid valves and closing the second solenoid valve. It can be pushed up and discharged from the air release valve, and the air lock can be eliminated.

According to the fourth aspect of the present invention, since the water supply pipe, the hot water return pipe, and the connection pipe are formed of a flexible plastic pipe, the pipe can be bent without a joint, and there is no sudden bending. Even if it is thin, the flow resistance is small, and even if there is a place where the slope of the pipe is not downgraded in the direction of the drain pipe, if the location of the drain pipe is lower than the water pipe and hot water return pipe to be drained The water in the water supply pipe and the hot water return pipe can be drained by the siphon principle.

According to the fifth aspect of the present invention, since a relief valve for releasing abnormal water pressure acting on the heat collector is provided below the heat collector, even if the heat collector has a structure that is weak against water pressure. , The collector can be protected from water pressure.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment of a direct heat collecting type solar water heating apparatus according to the present invention.

FIG. 2 is a partially cutaway perspective view showing the configuration of a heat collector used in this embodiment.

[Explanation of symbols]

 1 Heat Collector 2a, 2b Stainless Steel Thin Plate 3 Water Channel 4 Heat Collector Main Body 5 Case 6 Insulation Material 7 Transparent Plate 8 Hot Water Storage Tank 9 Insulation Container 10 Water Supply Pipe 11 Hot Water Return Pipe 12 Circulation Pump 13 First Solenoid Valve 14 Drain Pipe 15 Second solenoid valve 16 Connection pipe 17 Branch connection point 18 Third solenoid valve 19 Connection point 20 Check valve 21 Air vent valve 22 First temperature sensor 23 Second temperature sensor 24 Third temperature sensor 25 Controller 26 Relief valve 27 Adjusting pressure reducing valve 28 Water supply pipe 29 Hot water pipe 30 Hot water tap 31 Air vent valve 32 Safety valve

Claims (5)

[Claims] 1. A heat collector, a hot water tank installed below the heat collector, and a lower part of the hot water tank and a lower part of the heat collector connected to collect water in the hot water tank. A water pipe for supplying a hot water, a hot water return pipe for connecting the upper part of the heat collector and the upper part of the hot water tank to supply the hot water generated by the heat collector to the hot water tank, and the water pipe And a circulating pump connected to the circulating pump for pumping the water in the hot water storage tank to the heat collector, wherein a first solenoid valve is provided in the water pipe on the discharge side of the circulating pump. A drain pipe is branched and connected to the water pipe between the first solenoid valve and the heat collector, a second solenoid valve is provided in the drain pipe, and the hot water return pipe is connected to the water pipe. A connecting pipe to be connected is connected to the water pipe between the branch connection point of the drain pipe and the first solenoid valve, and A third solenoid valve is provided on the pipe, and a water stopping means for stopping the flow of water or hot water in the hot water return pipe between the connection point of the connecting pipe to the hot water return pipe and the hot water tank as necessary. A direct heat collecting type solar water heating device, which is provided with. 2. The direct heat collecting type solar hot water apparatus according to claim 1, wherein an air vent valve is provided above the heat collector. 3. The direct water supply pipe according to claim 1, wherein a water supply pipe is connected to a lower portion of the hot water storage tank via a pressure reducing valve so that a required water pressure is constantly applied to the hot water storage tank. Heat collecting solar water heater. 4. The direct heat collecting type according to claim 1, wherein the water supply pipe, the hot water return pipe, and the connecting pipe are formed of a flexible plastic pipe. Solar water heater. 5. The direct valve according to claim 1, further comprising a relief valve provided at a lower portion of the heat collector for releasing an abnormal water pressure acting on the heat collector. Heat collecting solar water heater.