JP2001065998A - Water heater utilizing solar heat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a heat collecting effect and reduce an electric power consumption by a method wherein a heat medium pipe is equipped with a reciprocating tube, reciprocating a heat medium in the same tube, while the reciprocating tube is equipped with a pump means, capable of sending the heat medium from the side of a heat medium tank to the side of a heat collector. SOLUTION: A solar heat utilizing water heating device S is equipped with a heat collector 1, heating a heat medium (water such as tap water or the like, for example) by solar light, a heat medium tank or a heat storage tank 9 and a heat medium tube 10 provided between the heat collector 1 and a hot-water storage tank 2. In this case, the heat medium in the hot-water storage tank 2 is reciprocated between the heat collector 1 and the hot-water storage tank 2 through the heat medium tube 10 whereby the temperature of the heat medium in the hot-water storage tank 2 is raised. Here, the heat medium tube 10 is equipped at least with a motor-driven pump 7 capable of sending the heat medium into reciprocating tubes 8a, 8b, which are reciprocating the heat medium in the same tube, from the side of the hot-water storage tank 2 to the side of the heat collector 1. According to this method, the amount of heat dissipation is reduced very much and a heat collecting performance is improved remarkably. Further, the amount of electric power consumption of the pump can also be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced circulation type solar hot water heater in which a heat medium heated by utilizing solar heat is reciprocated between a heat medium tank and a heat collector.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
A forced circulation solar water heater J is provided between a heat collector 51 for heating water as a heat medium by solar heat and a hot water storage tank 52 for storing hot water.
And a return pipe 54 for returning the heat medium from the heat collector 51 to the hot water storage tank 52. Further, for example, a circulation pump 55 is provided in the transfer pipe 53. The heat medium is forcibly circulated between the heat collector 51 and the hot water storage tank 52. In the figure, 56
Reference numeral denotes a hot water supply pipe for supplying hot water from the hot water storage tank 52, and reference numeral 57 denotes a water supply pipe for supplying water to the hot water storage tank 52 from a water supply or the like.

Here, in the heat collecting operation of the solar water heater J, the temperature difference ΔT (= T51−T52) between the heat medium temperature T51 in the heat collector 51 and the heat medium temperature T52 in the hot water storage tank 52 is determined. When the value is equal to or more than the value Ta, the heating medium is circulated by operating the circulation pump 55, and the temperature of the heating medium in the hot water storage tank 52 is raised.

On the other hand, the circulation of the heat medium is stopped by stopping the circulation pump 55 when the temperature difference ΔT becomes equal to or less than a predetermined value Tb (<Ta).

[0005] As described above, when the amount of solar radiation is fine, the circulation pump 55 is continuously operated from morning to collect heat until the temperature difference ΔT ≦ Tb. In addition, when the amount of solar radiation is small, the temperature difference ΔT decreases as soon as the operation of the circulation pump 55 starts, and ΔT ≦ Tb, and the operation of the circulation pump 55 stops. As a result, the circulation pump 55 repeatedly operates (ON) and stops (OFF) within a short time.

[0006] In the above-described solar water heating water heater, at least two pipes are required to circulate the heat medium between the heat collector and the hot water storage tank, i.e., a forward pipe and a return pipe. The heat collection efficiency was reduced due to heat dissipation loss in each tube.

[0007] In addition, during construction, maintenance and inspection, etc., work must be performed at different locations on the roof and its surroundings.
For example, depending on the form of the house, the plumbing work and the fixing work are not only complicated, but also pose a problem from the viewpoint of the safety of workers.

Further, in a system for detecting a temperature difference between a heat collector and a heating medium in a hot water storage tank and starting and stopping a circulation pump,
When the amount of solar radiation such as cloudiness is small, the above temperature difference ΔT
After the operation of the circulating pump is started, the temperature difference disappears immediately after the operation of the circulating pump, and the operation of stopping the circulating pump is repeated many times, thereby shortening the life of the circulating pump. Conversely, when the amount of solar radiation in fine weather is large, the circulating pump is operated continuously, and the power consumption during this period is large.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems and to provide an epoch-making solar hot water heater with high heat collection efficiency and low power consumption.

[0010]

Means for Solving the Problems In order to solve the above problems, a solar water heater according to the present invention comprises a heat medium tank for storing a heat medium and a heat collector for heating the heat medium with sunlight. A heating medium pipe is provided, wherein the heating medium pipe is a reciprocating pipe for reciprocating the heating medium in the same pipe, and pump means capable of sending the heating medium from the heating medium tank side to the heat collector side to the reciprocating pipe. And characterized by comprising:

[0011] Further, particularly between the reciprocating pipe and the heat medium tank,
A first connecting pipe provided with first valve means for adjusting the return amount of the heat medium from the heat collector side, and a second connecting pipe provided with second valve means for inhibiting return of the heat medium from the heat collector side The return pipe of the heat medium from the heat collector can be safely and reliably adjusted even if the reciprocating pipe is thickened in order to increase the amount of the heat medium to be heated.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, a solar water heating device S of the present invention is installed at a high position such as a roof or the like and heats a heat medium (for example, water such as tap water) by sunlight and stores the heat medium. A heat storage tank 9 provided with a hot water storage tank or the like as a heat medium tank to be stored, and a heat medium pipe 10 provided between the heat collector 1 and the hot water storage tank 2. By moving the medium back and forth between the heat collector 1 and the hot water storage tank 2 via the heat medium pipe 10, the temperature of the heat medium in the hot water storage tank 2 is increased.

The heat medium pipe 10 is a reciprocating pipe 8a for reciprocating the heat medium in the same pipe, and a pump means capable of sending the heat medium from the hot water storage tank 2 side to the heat collector 1 side to the reciprocating pipe 8a. At least a pump (hereinafter, referred to as a pump) 7 is provided.

In the solar water heating apparatus S, the return of the heat medium from the heat collector 1 is adjusted between the reciprocating pipe 8a and the hot water storage tank 2, particularly between the reciprocating pipe 8a and the pump 7. A first connecting pipe 4 provided with an electromagnetic valve 3 which is a first valve means, and a second connecting pipe provided with a check valve 5 which is a second valve means for inhibiting return of the heat medium from the heat collector 1 side. 6 is plumbed. Since a large number of connecting pipes are provided and a valve means is provided for each connecting pipe in this manner, even if the reciprocating pipe 8a is made thick to increase the amount of heating medium to be heated (the amount of heating medium to be transported), the heat collector It is possible to safely and reliably adjust the flow rate of the heat medium without breaking the valve means when the heat medium returns from the heat source.

The pump 7 is provided with a third connecting pipe 8b through which the heating medium reciprocates.
And the fourth connection pipe 8c. Since the inside of the heat storage tank 9 is piped in this manner, the heat collector 1 and the heat storage tank 9 are connected.
Are connected by the reciprocating pipe 8a. The first valve means and the second valve means are not limited to those described above, and at least the first connection pipe 4 and the second connection pipe are provided between the reciprocating pipe 8a and the pump 7 as a connection pipe. 6 may be connected, and three or more connecting pipes may be provided.

A fourth connection pipe 8c connected to the vicinity of the end of the heat medium pipe 10 in the heat collector 1 and to the bottom in the hot water storage tank 2.
A temperature sensor TS1 for detecting the temperature of the heat medium in the heat collector 1 and a temperature sensor TS2 for detecting the temperature of the heat medium in the hot water storage tank 2 are provided near the ends of the heat collector 1, respectively. Is provided with a water level sensor 17, which will be described later, and a detection signal from these sensors is configured to be input to a control device CS that performs opening / closing control of the electromagnetic valve 3, control of starting / stopping of the pump 7, and the like. The temperature sensors TS1 and TS2 use a thermocouple, a thermistor, or the like.

As shown in detail in FIG. 2, the heat collector 1 has a header tube 15 mainly composed of a stainless steel tube with holes, a foamed heat insulating material, a decorative cover and the like. A double vacuum glass tube 16 is connected, and a water level sensor 17 including a flow switch and an air release valve 18 are provided on an upper portion 15a of the header tube 15 located above the roof. ing. Double vacuum glass tube 1
Reference numeral 6 denotes an inner glass tube into which a heat medium enters, which is inserted into the outer glass tube, and a vacuum is maintained between the outer glass tube and the inner glass tube. On the other hand, the header tube 15 located below the roof
A temperature sensor TS <b> 1 for measuring the temperature of the heat medium in the heat collector 1 is disposed near one end of the heat medium pipe 10 in the lower part 15 b of the heat medium pipe 10.

The position of the temperature sensor TS1 is located below the heat collector 1 as described above, because the temperature of the heat medium located above the lower portion of the heat collector 1 is generally higher in many cases. This is for detecting the temperature of the heat medium more accurately by detecting the temperature of the heat medium. Further, the position of the temperature sensor TS2 is disposed at the bottom of the hot water storage tank 2 as described above for the same reason.

The heat collector 1 is in a state before the heat medium enters the heat collector 1, that is, the header tube 15 and the double vacuum glass tube 1
When the heat medium 6 is completely empty, this is as schematically shown in FIG. 3 (a). When the heat medium fills the entire heat collector 1 and is full, the heat medium is blacked out in FIG. 3 (b). It is as shown. The manner in which the heat medium is sent from the heat collector 1 to the hot water storage tank 2 is as shown in FIG.

In the solar water heater S configured as described above, the temperature T1 detected by the temperature sensor TS1 provided in the heat collector 1 and the temperature sensor TS in the hot water storage tank 2
2, the difference (T1-T2) from the temperature T2 detected is ΔT
c (= approximately 2 ° C .: the minimum temperature difference at which the heat collector 1 can heat the heat medium), the pump 7
Is started to supply the heat medium from the hot water storage tank 2 to the heat collector 1.

The heat medium supplied into the heat collector 1 is constantly monitored by a water level sensor 17, and when it is detected that the inside of the heat collector 1 is full, the operation of the pump 7 is stopped and the electromagnetic valve 3 is turned off. Close.

The solar heat is collected and the temperature T1 detected by the temperature sensor TS1 and the temperature T detected by the temperature sensor TS2.
When it is detected that the difference (T1−T2) from ２2 is greater than or equal to ΔTd (= 10 ° C .: optimally at 8 ° C. to 12 ° C.),
The solenoid valve 3 is opened to return the heat medium from the heat collector 1 into the hot water storage tank 2.

In this way, by repeating the above operations at the time of collecting heat, the temperature of the heat medium in the hot water storage tank 2 can be increased. Note that a hot water supply pipe 11 and a water supply pipe 12 are connected to the hot water storage tank 2.

Next, a method for preventing freezing of the piping of the solar water heater S will be described. When the temperature of the heat medium in the hot water storage tank 2 is higher than a reference temperature (for example, 2 ° C .: if this is lower than 2 ° C., it becomes difficult to prevent the freezing of the pipe with the heat capacity of the heat medium in the hot water storage tank 2), The heat of the heat medium in the hot water storage tank 2 prevents the heat medium in the pipe from freezing. When the temperature of the heat medium in the hot water storage tank 2 is lower than the reference temperature, the heat medium in the hot water storage tank 2 is partially replaced with tap water, and the heat medium in the pipe is frozen with the calorific value of the tap water. To prevent.

More specifically, as shown in FIGS. 4 (a) to 4 (c), when the temperature of the heating medium in the hot water storage tank 2 is 2 ° C. or higher, the pump 7 is operated at regular intervals, and The heating medium in the inside is periodically sent to the heating medium tube 10 to warm the inside of the heating medium tube 10 (FIG. 4A → FIG. 4B). Here, when the cooled heat medium returned from the heat medium pipe 10 is 4 ° C. or higher, the heat medium is stored in the lower part of the hot water storage tank 2. , The amount of heat in the hot water storage tank 2 can be utilized in order from the lower heat medium to the upper heat medium (FIG. 4 (c)).

When the temperature of the heat medium in the hot water storage tank 2 is lower than 2 ° C., a certain amount of the heat medium in the hot water storage tank 2 is replaced with tap water, and the operation of the pump 7 moves the heat medium in the same manner as described above. This can prevent the heat medium in the heat medium pipe 10 and the hot water storage tank 2 from freezing.

In this embodiment, the case where tap water is used as a heating medium for reciprocating the reciprocating pipe has been described.
The present invention is not limited to this, and a liquid having a large heat capacity may be used and the liquid may be circulated between the heat medium tank and the heat collector. A liquid such as isolated tap water may be heated.

[0028]

Next, more specific embodiments of the present invention will be described.

The solar hot water heater used in this embodiment is:
It had a basic configuration as shown in FIGS.
Here, the heat collector is composed of a double vacuum glass tube and a header tube, has an effective heat collecting area of 3.22 m ² , and has a heat medium amount of 5 when filled with water.
0 liter. The inner diameter of the reciprocating pipe was 12 mm, and the pump used was an electric pump having a head of 10 m and a flow rate of 8 to 10 L / min.

As a comparative example of the above-described apparatus, FIG. 6 is used as a basic configuration, and a specific configuration uses a solar-heated water heater under the same conditions as above.

FIG. 5 shows a change in the temperature of the heat medium in the hot water storage tank (□: present invention, comparative example: ●) and a change in power consumption of the pump (△: present invention, ×: comparative example). , Average outside air temperature during heat collection: 10.1 ° C, solar radiation: 5423 kca
1 / (m ² · day), ground angle of collector: 30 ° (azimuth:
True south).

According to this embodiment, as shown in FIG.
The heat collection amount was improved by about 2 to 3% on average, and it was found that the heat collection effect was particularly effective as the heat collection time became longer. In addition, the power consumption of the pump was significantly reduced to about 1/5 or less.

[0033]

As described above, according to the solar water heating apparatus of the present invention, only one reciprocating pipe for reciprocating the heat medium between the heat collector and the hot water storage tank is required. The amount of heat radiation is much smaller than that of a solar water heater using a return pipe, and the heat collection performance is extremely good. Further, the power consumption of the pump for delivering the heat medium can be significantly reduced as compared with the conventional case. Further, the size of the entire apparatus can be easily reduced.

Further, a connecting pipe provided with a valve means for adjusting the return of the heat medium from the heat collector side between the reciprocating pipe and the heat medium tank, and the return of the heat medium from the heat collector side are prohibited. It is possible to safely and reliably adjust the return of the heat medium from the collector even if the reciprocating pipe is thickened in order to increase the amount of the heat medium to be heated by piping the connection pipe provided with the valve means for performing the heating. it can.

From the above, it is possible to quickly heat the heat medium throughout the year, and particularly to heat the heat medium quickly even when the temperature is low in winter or the like.
It is possible to provide a solar water heating water heater that is extremely easy to save energy and miniaturize, and has extremely excellent reliability.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram schematically illustrating an embodiment of a solar water heating water heater according to the present invention.

FIG. 2 is a partially omitted perspective view schematically illustrating a part of a heat collector according to the present invention.

FIGS. 3A to 3C are partially omitted general configuration diagrams schematically illustrating a state in which a heat medium moves between a heat collector and a hot water storage tank according to the present invention.

FIGS. 4A to 4C are schematic cross-sectional views illustrating the prevention of freezing of the solar water heater according to the present invention.

FIG. 5 is a graph showing the relationship between the heat collection time and the temperature in the hot water storage tank, and the relationship between the heat collection time and the power consumption of the pump in Examples and Comparative Examples of the present invention.

FIG. 6 is an overall configuration diagram schematically illustrating a conventional solar water heater.

[Explanation of symbols]

 1: Heat collector 2: Hot water storage tank (heat medium tank) 7: Pump 8a: Reciprocating pipe 3: Solenoid valve (first valve means) 4: First connecting pipe 5: Check valve (second valve means) 6: Second connecting pipe 9: Thermal storage tank 10: Heat medium pipe 17: Water level sensor CS: Control device S: Solar water heater TS1, TS2: Temperature sensor

Claims (2)

[Claims] 1. A solar water heater using a heat medium pipe, wherein a heat medium pipe is disposed between a heat medium tank for storing a heat medium and a heat collector for heating the heat medium with sunlight. A solar water heater comprising: a reciprocating pipe for reciprocating a heat medium in the same pipe; and pump means capable of sending the heat medium in the reciprocating pipe from the heat medium tank side to the heat collector side. . 2. A first connecting pipe provided between the reciprocating pipe and the heat medium tank, the first connecting pipe having first valve means for adjusting a return amount of the heat medium from the heat collector to the heat medium tank. The solar heat according to claim 1, wherein a second connection pipe provided with a second valve means for inhibiting return of the heat medium from the heat collector side to the heat medium tank side is provided. Use hot water equipment.