JPH0712406A - Hot-water supplier utilizing solar heat - Google Patents

Abstract

PURPOSE:To contrive a reduction in installation cost as well as in operation cost, space saving, an improvement in durability and the facilitation of maintenance. CONSTITUTION:A series of circulating route, consisting of an auxiliary heating device 2 (internal U-tube 2a) a water feeding tube 3 a solar heat collecting device 1 a hot-water supplying tube 4 the auxiliary heating device 2, is constituted in a system while the water supplying pressure of city water way 5 acts on the circulating route whereby water, having a given pressure, is reserved and retained in the circulation route under the condition of full of water. When an electric heater 2b is operated, water, filling the lower part of the heating side tube 2a1 of the internal U-tube 2a, is heated locally by the heat generated by the electric heater 2b whereby the temperature of the water becomes higher than the temperature of water, filling the other part of the circulation route. The water, heated in such a way, flows into a solar heat collecting device 1 by the difference of specific gravities while the water in the solar heat collecting device 1 flows into the heating side tube 2a1 and is heated by the electric heater 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar hot water supply facility for supplying hot water using solar heat.

[0002]

2. Description of the Related Art In a solar heat collecting apparatus, although it is possible to collect a sufficient amount of heat necessary for hot water supply if averaged over the year, there are variations in the weather, It becomes necessary to supplement the lack of heat. As measures against this, there are a method of providing a huge hot water pool tank capable of averaging the change in weather above the practical temperature, and a method of supplementing the insufficient amount of heat with an auxiliary heat source (auxiliary heat source method). The former method requires huge equipment and is not practical. Since the latter method can be relatively easily performed, it is widely used.

[0003] Conventional auxiliary heat source systems include a system for supplementing a shortage of heat amount by a solar heat collector by a reheating device (hereinafter referred to as a reheating system) and an auxiliary heater in a hot water storage container. There are two types of methods (hereinafter referred to as an internal auxiliary heater method) for compensating for each other.

[0004]

In the reheating system, generally, an electric hot water boiler, a gas hot water boiler, a kerosene boiler, etc. are used as auxiliary heat sources, and these auxiliary heat sources are activated during hot water supply to cause insufficient heat quantity. Since it is a system that supplements the amount of electricity instantaneously, it requires an auxiliary heat source facility with the same large capacity as when there is no solar heat collector in order to withstand instantaneous use during hot water supply. Therefore, this method tends to be over-equipped, which is a major obstacle to practical use of solar hot water supply equipment. Further, in particular, any of the burner methods using gas or kerosene cannot withstand long-term use in terms of maintenance.

On the other hand, the internal auxiliary heater system does not need to be used instantaneously and a heat source of a small capacity is sufficient. Therefore, there are no problems such as high equipment cost as compared with the above-mentioned additional cooking system, but the following problems still exist. Is pointed out. In other words, the structure is complicated and there is a problem in maintenance.Because it is ineffective in preventing the freezing of piping in cold regions, the winter use in this area is stopped or special freezing prevention is required. It is necessary to take measures.

Conventionally, there is also an external auxiliary heater type solar hot water supply system, but it is necessary to adopt a forced circulation system using a circulation pump, which complicates the structure, costs, secures a place for installation, and has a maintenance aspect. There was a problem.

An object of the present invention is to solve the above-mentioned problems in the conventional method, thereby reducing the installation cost and operating cost of the solar hot water supply facility, saving space, improving durability and facilitating maintenance. It is in.

[0008]

According to a first aspect of the present invention, there is provided a solar heat water supply facility, which comprises a hot water storage container, water is supplied through a water supply pipe, and hot water is taken out through the hot water supply pipe.
A communication pipe part for communicating the water supply pipe and the hot water supply pipe with each other at a position lower than the solar heat collector, and installed in the middle of the communication pipe part, allowing a flow from the hot water supply pipe to the water supply pipe, and in the opposite direction. A check valve for preventing flow, a water supply pipe side portion of the communication pipe portion, and a pipe path including the water supply pipe, and in a position lower than the solar heat collecting device, and the solar heat collecting device. And an auxiliary heat source whose operation is controlled via a first temperature sensor that detects the hot water supply temperature from the.

In the solar hot water supply facility according to a second aspect of the present invention, the antifreezing means is added to the above construction. That is, the second temperature sensor detects the water temperature of a portion of the piping system where freezing is likely to occur, and the heating means is operated and controlled based on this detection signal.

[0010]

In the solar hot water supply system of the present invention, a series of natural circulation paths including the solar heat collector and the auxiliary heat source are formed in the piping path, and the amount of hot water required for hot water supply is secured by the amount of heat collected by the solar heat collector. If it is possible, the hot water is supplied as it is without activating the auxiliary heat source. Only when the amount of heat collected by the solar heat collector is insufficient, activate the auxiliary heat source using the first temperature sensor, and Natural circulation is performed by convection of water inside, and by utilizing this, the required amount of hot water can be stored in the solar heat collector at all times. When hot water is supplied, the check valve prevents tap water from directly entering from the communication pipe.

Further, in the solar hot water supply system of the present invention, the second temperature sensor detects the water temperature of a portion of the pipe system where freezing is likely to occur, activates the auxiliary heat source, and causes convection of water in the pipe passage. Freezing is prevented by allowing natural circulation.

[0012]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 shows an example of installation of solar hot water supply equipment according to this embodiment. A solar heat collector 1 is installed and arranged on a roof of a building with a predetermined inclination angle, and is connected by a water supply pipe 3 and a hot water supply pipe 4 to an auxiliary heating device 2 installed on the lower side of the building. The auxiliary heating device 2 communicates with a water supply pressure source, for example, a water supply 5 and a hot water supply tap 6 arranged in the room.

FIG. 2 shows a system example of the solar hot water supply facility. The solar heat collector 1 has, for example, a cylindrical long metal hot water storage container 1a2 whose outer surface is coated with a selective absorption film and which is coaxial with a transparent long cylindrical glass container 1a1 having a vacuum inside. Heat collecting hot water storage section 1a which is inserted and fixed in
Are arrayed in plural (for details, refer to Japanese Patent Publication No. 3-56387 by the present applicant). Each heat collecting hot water storage portion 1a communicates with the first header pipe 1b through the long pipe 1a3 inserted from the upper end opening of the hot water storage container 1a2 to near the lower closed end, and the upper end opening of the hot water storage container 1a2 is It communicates with the second header pipe 1c through the short pipe 1a4. Further, in this embodiment, the solar heat collector 1 is installed and arranged so that the upper end opening of the hot water storage container 1a2 is located in the upper direction of the inclination, and the water supply pipe 3 is connected to the inlet 1b1 of the first header pipe 1b by piping. , The second header tube 1
The hot water supply pipe 4 is connected to the outlet 1c1 of c. The number and method of arrangement (serial or parallel) of the heat collecting hot water storage unit 1a may be appropriately determined in consideration of various conditions such as installation location, amount of hot water used, and weather environment.

As shown in FIG. 3, the auxiliary heating device 2 includes a heating side pipe portion 2a1, a hot water supply side pipe portion 2a2, and a heating side pipe portion 2a1.
A series of internal U-shaped pipes 2a consisting of a bottom pipe portion 2a3 for connecting the hot water supply side pipe portion 2a2 to each other, an auxiliary heat source capable of heating the water in the heating side pipe portion 2a1 such as an electric heater 2b, and a heating side pipe portion 2a1. The check valve 2c for preventing backflow of water from the hot water supply side pipe portion 2a2 is integrally housed in the box 2d, and in order to prevent a fire accident, these members are provided in the box 2d. It is covered with a heat insulating material such as fireproof rock wool 2e. A water supply pipe 3 is connected to the end of the heating side pipe portion 2a1, and an inlet pipe 2a4 leading to the water supply 5 is branched and connected in the middle thereof. On the other hand, the hot water supply side pipe portion 2a
A hot water supply pipe 4 is connected to an end portion of 2, and a hot water supply pipe 2a5 leading to a hot water tap 6 is branched and connected to an intermediate portion thereof. The electric heater 2b is, for example, a sheath heater, and the heating side tube portion 2
It is arranged below a1. This electric heater 2
b is connected by a lead wire to an electric outlet 2f arranged in the box 2d, and water in the heating side tube portion 2a1 can be heated if necessary. The check valve 2c is provided on the hot water supply side pipe portion 2a2 against the flow of water in the internal U-shaped pipe 2a.
To the heating side tube portion 2a1 is allowed, and the opposite flow is prevented. The check valve 2c serves to prevent tap water from the inlet pipe 2a4 from flowing backward through the internal U-shaped pipe 2a and directly flowing out from the hot water inlet pipe 2a5 during hot water supply.

In FIG. 2, the water supply 5 is always open and the hot water tap 6 is closed except when hot water is being supplied. Therefore, in the system, the auxiliary heating device 2 (internal U-shaped pipe 2a) → water supply pipe 3 → solar heat collector 1 → hot water supply pipe 4 → auxiliary heating device 2
A series of circulation paths composed of the (internal U-shaped pipe 2a) is configured, and the water supply pressure of the water supply 5 acts on this circulation path, so that water having a constant water pressure is stored and held in the circulation path in a full state. . The water supply pressure of the water supply 5 may be adjusted to an appropriate pressure by using the pressure reducing check valve 7.

When the water stored in the heat collecting hot water storage unit 1a of the solar heat collecting apparatus 1 receives the solar heat collected by the selective absorption film of the hot water storage container 1a2 and rises in temperature, the temperature rises due to the difference in specific gravity. The inside of the hot water storage container 1a2 rises in an inclined direction and flows out from the opening of the hot water storage container 1a2 into the second header pipe 1c. On the other hand, the water in the second header pipe 1c descends and flows into the hot water storage container 1a2. The water in the solar heat collector 1 is
While repeating the above natural circulation cycle, it gradually changes to hot water. Then, when the hot water tap 6 arranged inside the room is opened, hot water is supplied from the solar heat collector 1 through the hot water supply pipe 4, the hot water supply side pipe portion 2a2 of the internal U-shaped pipe 2a, and the hot water supply port pipe 2a5. The hot water from the solar heat collector 1 is
By mixing with the tap water by the mixing valve 10 connected to the hot water inlet pipe 2a5, it can be taken out from the hot water tap 6 as hot water having an appropriate temperature (for example, set temperature 42 ° C).

When a sufficient amount of heat can be collected in the summer and the like, it is possible to supply a sufficient amount of hot water only by the heat collecting action of the solar heat collector 1 described above, but in the winter and a long period of time. When the weather is bad, the amount of heat collected by the solar heat collector 1 may be insufficient for the amount of heat required for hot water supply. In such a case, the electric heater 2b arranged in the auxiliary heating device 2 is operated to compensate for the insufficient amount of heat. The operation control of the electric heater 2b is performed in the following manner.

A first temperature sensor S1 is arranged at a position where the temperature of the hot water supplied from the solar heat collector 1 can be detected, for example, in the vicinity of the outlet 1c1 of the second header tube 1c. The temperature T1 of the hot water detected by the first temperature sensor S1 is output as a detection signal to the control panel 8 that controls the operation of the electric heater 2b. The control panel 8 successively compares the preset temperature T0 with the detection signal T1 output from the first temperature sensor S1, and when T1 <T0, activates the electric heater 2b to satisfy T1 ≧ T0. In that case, the operation of the electric heater 2b is stopped. It is preferable that the set temperature T0 of the control panel 8 is adjustable and has an appropriate temperature range (operating temperature difference: T0min to T0max).
The reason why the set temperature T0 can be adjusted is
Since the rate of dependence on the amount of heat collected by the solar heat collector 1 is large, the set temperature T0 is set in a relatively low temperature range (for example, 45 to 55 ° C), and in winter and the like, conversely,
This is because it is a good idea to set the set temperature T0 in a relatively high temperature range (for example, 55 to 65 ° C.), because the rate of dependence on the amount of heat supplemented by the electric heater 2b increases. In winter, there is no concern about excessive heat compared to summer,
There is also the circumstance that a large amount of hot water is used. The reason why the temperature range (operating temperature difference) is provided is that if the operation control of the electric heater 2b is performed based on a specific temperature value (for example, 50 ° C.), the operation interval becomes short and the heat loss becomes large. is there. The same applies when the operating temperature difference is small. It is economical to set the maximum operating temperature difference (T0max-T0min) to around the overnight heat radiation temperature difference (for example, 5 to 15 ° C). For example, the set temperature T0 is 55 to 6
When set within the range of 5 ° C, the control panel 8 detects that the detection signal T1 from the first temperature sensor S1 is 55 ° C (T0mi).
n) The electric heater 2b is activated when
When the detection signal T1 reaches 65 ° C. (T0max), the operation of the electric heater 2b is stopped.

FIG. 4 shows an example of an operation control circuit of the electric heater 2b by the first temperature sensor S1. In the figure, 11 is a high temperature side temperature controller, 12 is a low temperature side temperature controller, 13 is a relay, and 11a is a normally closed contact of the high temperature side temperature controller 11.
a is a normally open contact of the low temperature side temperature controller 12, which is turned on at a set temperature, and 13a is a relay 13
The self-holding normally open contact of
The contact 11a and the contact 12a are inserted in series, and the contact 13a is connected and inserted in parallel with the contact 12a. Reference numeral 13b is a normally open relay contact inserted in the circuit of the electric heater 2b, which is turned on when the relay 13 is energized and excited.

When the electric heater 2b is activated, the heat generated by the electric heater 2b locally heats the water filling the lower portion of the heating side tube portion 2a1 of the internal U-shaped tube 2a, and the water filling the other portions of the circulation path. It becomes higher than the temperature. The heated water rises in the heating side pipe portion 2a1 due to the difference in specific gravity, flows into the solar heat collector 1 through the water supply pipe 3, and the water in the solar heat collector 1 is heated by the hot water supply pipe 4 and the hot water supply pipe 2a2. , Flows into the heating side tube portion 2a1 through the bottom tube portion 2a3, and is heated by the electric heater 2b. The water in the circulation path gradually changes to high-temperature hot water and is stored in the solar heat collector 1 while repeating the above natural circulation cycle. That is, the water in the circulation path is locally heated by the electric heater 2b and the temperature thereof rises, whereby convection (natural circulation) of water occurs in the circulation path, whereby the heated water collects the solar heat collector. The result is that it gradually replaces the water in 1. Then, when the temperature T1 detected by the first temperature sensor S1 reaches the set temperature T0 (TOmax), the operation of the electric heater 2b is stopped by the control panel 8.

As described above, in the solar hot water supply system of this embodiment, a series of circulation paths including the solar heat collector 1 and the auxiliary heating device 2 (electric heater 2b) are formed in the piping path, and the solar heat collector is installed. If the required amount of hot water can be secured with the heat collection amount of 1, the hot water is supplied as it is,
The electric heater 2b of the auxiliary heating device 2 is operated only when the amount of heat collected by the solar heat collector 1 is insufficient.
As a result, the required amount of hot water can be stored in the solar heat collector 1 at all times by utilizing natural circulation due to convection of water in the circulation path.

In addition, when it is expected to freeze in winter during use in cold regions, a portion of the piping system (circulation route) where freezing is likely to occur, such as the bottom of the internal U-shaped tube 2a of the auxiliary heating device 2. The second temperature sensor S on the bottom tube portion 2a3
2 is arranged and the detection signal T from the second temperature sensor S2
2, the electric heater 2b according to the embodiment described above.
Control operation. As described above, natural circulation of water occurs in the circulation path due to the heating of the electric heater 2b, and the temperature of the water in the circulation path gradually rises. Therefore, freezing in winter can be effectively prevented. It is an extremely effective and simple means for preventing freezing. The set temperature T0 ′ of the control panel 8 corresponding to the detection signal T2 can be adjusted according to the set temperature T0 and has an appropriate temperature range (for example, 1 ° C. to 5 ° C.). Is good.
In practice, the optimum range is set in consideration of various conditions such as the area of use and the installation location of the hot water supply system. The operation control of the electric heater 2b by the second temperature sensor S2 can be performed by the operation control circuit shown in FIG. Further, the position of the second temperature sensor S2 is not particularly limited, but it is generally desirable to dispose the second temperature sensor S2 at the lowest part of the piping system. This is because water having a low temperature has a high specific gravity and is considered to be stored in the lowest part of the piping system. For this reason, the second temperature sensor S2 is arranged in the bottom tube portion 2a3 of the inner U-shaped tube 2a in this embodiment.

In this embodiment, as the solar heat collector 1, a so-called vacuum type solar heat collector in which a plurality of heat collecting hot water storage units 1a are arranged is used. The reason is such a solar heat collector. 1 is superior to the so-called flat plate type solar heat collector in the heat collection efficiency and the heat retaining performance of the hot water, so that the auxiliary heat source load can be small. Of course, the present invention is not limited to this, and is applicable to so-called flat plate solar heat collectors and the like. In other words, the solar heat collector 1
It is sufficient that it has both a solar heat collecting function and a necessary amount of hot water storage function, regardless of the type or model thereof.

Further, as the auxiliary heating device 2, a unit type in which an internal U-shaped tube 2a, an electric heater 2b as a heating means, and a check valve 2c are integrally housed in a box 2d is used. The unitization is not always essential, and these constituent elements may be arranged separately in the piping path. However, by adopting the unit type as in this embodiment, there is an advantage that heat loss can be suppressed to the minimum and the work such as piping and installation can be facilitated. further,
As for each component, the internal U-shaped pipe 2a may be replaced with another suitable pipe structure as long as it has a function of connecting the water supply pipe 3 and the hot water supply pipe 4 to form a series of circulation paths. Yes, electric heater 2b
Can be replaced with other auxiliary heat sources such as gas and kerosene as long as the water in the water supply piping system of the circulation path can be locally heated at a position lower than the solar heat collector 1. However, in the solar heat collector 1 for general households as in this embodiment, since the hot water storage capacity is small, by using electric power as an auxiliary heat source, maintenance, cost, etc. are improved as compared with the case of using gas, kerosene, or the like. Is extremely advantageous in terms of. On the other hand, in the case of a commercial solar heat collector having a large hot water storage capacity, it is more cost effective to use gas, kerosene, or the like as an auxiliary heat source. The electric heater 2b and other auxiliary heat sources may be arranged in the middle of the pipe path including the heating side pipe portion 2a1 and the water supply pipe 3 and at a position lower than the solar heat collecting apparatus 1. The position is not limited.

[0026]

The present invention has the following unique effects.

(1) As compared with the conventional additional cooking system, a small capacity auxiliary heat source is sufficient. Therefore, by making the auxiliary heat source equipment compact, it is possible to reduce installation and operating costs and save space.

(2) Since it is a natural circulation system, devices for forced circulation in the conventional system (a hot water storage tank, a circulation pump, etc.) are not required, which is advantageous in terms of cost and maintenance.

(3) The structure of the auxiliary heat source is simplified, which is advantageous in terms of cost and maintenance. Also,
The durability of the auxiliary heat source is also improved.

(4) The heat loss can be minimized by using the auxiliary heating device in which the internal U-tube, the auxiliary heat source, and the check valve are integrally housed in the box via the heat insulating material. At the same time, operations such as piping and installation can be facilitated.

(5) An extremely effective and simple anti-freezing means can be provided by detecting the water temperature of a portion of the piping system where freezing easily occurs by the second temperature sensor and controlling the operation of the auxiliary heat source based on this detection signal. Can be provided.

(6) Due to the above effects, the present invention contributes to reduction of installation cost and operating cost, reduction of noise, space saving, improvement of durability and facilitation of maintenance in solar hot water supply equipment.

[Brief description of drawings]

FIG. 1 is a diagram showing an installation example of solar hot water supply equipment according to an embodiment.

FIG. 2 is a diagram showing an example of a system for solar hot water supply equipment according to an embodiment.

FIG. 3 is a diagram showing an example of a unit of an auxiliary heating device.

FIG. 4 is a diagram showing an operation control circuit of an electric heater.

[Explanation of symbols]

 1 Solar Heat Collector 2 Auxiliary Heater 2a Inner U-Shape 2a1 Heating Side Pipe 2a2 Hot Water Supply Side Pipe 2a3 Bottom Pipe 2b Electric Heater 2c Check Valve 2d Box 2e Insulation Material 3 Water Supply Pipe 4 Hot Water Supply Pipe 5 Water Supply 6 Hot Water Supply Stopper 8 Control panel

Claims (2)

[Claims] 1. A solar heat collector having a hot water storage container, which is supplied with water through a water supply pipe and takes out hot water through the hot water supply pipe, and the water supply pipe and the hot water supply pipe are lower than the solar heat collector. Of the communication pipe, a check valve installed in the middle of the communication pipe to allow the flow from the hot water supply pipe to the water supply pipe and prevent the flow in the reverse direction, and the water supply of the communication pipe Via a first temperature sensor which is arranged in the middle of the pipe path including the pipe side portion and the water supply pipe and at a position lower than the solar heat collector, and which detects the hot water supply temperature from the solar heat collector. A solar hot water supply facility comprising an operation-controlled auxiliary heat source. 2. The solar hot water supply equipment according to claim 1, wherein a water temperature at a portion of the piping system where freezing is likely to occur is detected by a second temperature sensor, and the auxiliary heat source is operated and controlled based on the detection signal. .