JPS6044765A - solar water heater - Google Patents

Abstract

PURPOSE:To make it possible to obtain quickly hot water having a desired temperature in a hot water storage tank and to supply the hot water, by confining capsules in the hot water storage tank, in which capsules a latent heat type heat accumulator is enclosed for heating supplied water, and allowing hot water to be supplied by the elevation of the water level due to water supply. CONSTITUTION:A number of cubic capsules 9 in which a latent heat type heat accumulating material 10 are enclosed are confined in a hot water storage tank 5. As the latent type heat accumulating material 10 usually use is make of inorganic compounds having a melting point on the order of 30 deg.C or organic compounds such as paraffin, polyethylene glycols, etc. When hot water that has been heated in a heat collector 1 is passed via a return path 8 to the upper part in the hot water storing tank 5, the latent type heat accumulating material in the capsules 9 present in said part accumulates heat of the hot water near to the melting point, and then the solid phase thereof turns to the liquid phase, and as water is supplied from a water supply pipe 12, the water level in the hot water storage tank 5 rises and the hot water overflowing into a hot water supply pipe 13 is delivered. The cold water supplied at this time flows through the capsules 9, during which it is heated quickly by the sensible heat of the latent type heat accumulating material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a natural circulation type solar water heater in which water is heated while being naturally circulated between a heat collector and a hot water storage tank.

[Background technology]

Conventionally, in natural circulation type solar water heaters, the water filled in the hot water storage tank is gradually warmed by circulating through natural convection between the heat collector and the hot water storage tank, and only the warmed water is stored in the hot water storage tank. It is said that it will be done. However, conventionally, the hot water storage tank had a large capacity (
Approximately 2001). Therefore, heat radiation from the large surface area reduces thermal efficiency, and in some cases, the temperature of the water may drop. The temperature drop was especially severe at night.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a solar water heater that reduces the temperature drop of hot water in a hot water storage tank.

[Disclosure of the invention]

In order to achieve the above objectives, the inventor has completed this invention after extensive study.

This invention is a solar water heater that is equipped with a hot water tank above the heat collector, and water is naturally circulated between the two, and water is supplied to the lower part of the hot water tank. The gist of this solar water heater is that it has a built-in capsule containing a latent heat storage material that warms the water, and hot water is supplied by raising the water level as the water is supplied. Hereinafter, an embodiment thereof will be described in detail based on the accompanying drawings.

As shown in FIGS. 1 and 2, a heat collector 1 is a known type that includes a heat collector plate 2 having a water channel 3 and a transparent plate 4 covering the upper surface of the heat collector plate 2 in a case with an open top surface. A hot water storage tank 5 located above the heat collector 1 is sealed with a heat insulating material 6, and is connected to the heat collector 1 by an outflow channel 7 and a return channel 8.

A water supply pipe 12 enters the lower part of the hot water storage tank, and a hot water supply pipe 13 extends from the upper part of the hot water storage tank. Water heated by the heat collector 1 enters the hot water storage tank 5 through the opening of a return channel 8 extending to the upper part of the hot water storage tank 5 by natural convection. Water is stored in the hot water tank 5 in advance, and the water enters the water channel 3 of the heat collector 1 from the outflow channel 7 by natural convection. As shown in FIGS. 3 and 4, the hot water storage tank 5 contains a large number of cubic capsules 9 in which a latent heat storage material 10 is sealed. The latent heat type N heat material 10 is 30℃
CaCl2 H61120, Na21 with melting points around
1po 4 ・121120, Na2 SO4' 10
Inorganic compounds such as 1120 and organic compounds such as paraffin and polyethylene glycol are generally used. but,
A substance whose melting point is not around 30°C may be used.

On the other hand, the capsule 9 is a molded product made of water-resistant and chemically stable polyethylene, etc., and has many grooves 11 on its surface to increase the heat exchange efficiency by increasing the surface area per volume.
・ is provided. These grooves 11...
It is also useful for absorbing changes in volume of latent heat storage materials, which undergo large volume changes during phase changes between solid phases.

Cubic capsules can be packed tightly into a hot water storage tank that is shaped like a rectangular parallelepiped. However, at that time, the water in the hot water storage tank is not blocked by the capsule and can continue to move through the grooves on the surface of the capsule as water channels.

Next, the operation of the solar water heater according to the present invention will be explained. As shown in Fig. 1 and Fig. 2, the hot water storage tank 5
Inside, water is supplied to a level equal to or lower than the 130 hot water pipes. When convection begins and hot water heated by the heat collector 1 enters the upper part of the hot water storage tank 5 from the condensate channel 8, the latent heat storage material in the capsule 9 in that area transfers the heat of the hot water to the melting point. After storing heat up to around 30 degrees Celsius,
Phase changes from solid phase to liquid phase. Similarly, all latent heat storage materials undergo a phase change from solid phase to liquid phase due to natural circulation. The water temperature at this time is close to the melting point of the latent heat storage material. The water supply pipe 12 is connected to the center or lower part of the hot water storage tank 5 where all the latent heat storage materials have accumulated heat and become a liquid phase.
When water is supplied from the hot water tank 5, the water level in the hot water storage tank 5 rises and hot water overflows into the hot water supply pipe 13 located at the top. On the other hand, the cold water supplied at this time is
While passing between..., the latent heat storage material undergoes a phase change from the liquid phase to the solid phase, and is rapidly heated by the associated heat radiation and the sensible heat of the latent heat storage material itself. Therefore, if water continues to be supplied, all the heat stored in the latent heat storage material in all the capsules 9 in the hot water storage tank 5 will be used to warm the cold water supplied to the hot water storage tank 5. As the water level rises, a large amount of hot water, which has been warmed to a temperature near the melting point, is supplied from the hot water supply pipe 13.

Since the latent heat type heat storage material has a small specific heat below the melting point, it has the characteristic that it quickly rises to the melting point and stores heat near the melting point until the entire latent heat type heat storage material liquefies. Therefore, if the melting point is adjusted to the temperature of the hot water to be supplied as in the example, that is, if a substance having almost the same melting point as that temperature is used as the latent heat type heat storage material, when the latent heat type heat storage material stores heat, A large amount of hot water is produced.

Although the capsule containing the latent heat storage material constituting the solar water heater according to the present invention has a cubic shape with a large number of grooves on its surface in the embodiment, there is no particular restriction on its shape.

Since the latent heat type M heating material needs to cause a phase change from a liquid phase to a solid phase when water is supplied, its melting point must be higher than the average maximum water supply temperature of water when it is supplied into the hot water tank. is preferred. In addition, the melting point is lower than the average minimum temperature rise of the hot water that is heated by the heat collector and sent into the hot water storage tank, to ensure that it is melted by the hot water sent into the hot water storage tank. It is preferable.

The hot water tank constituting the solar water heater according to the present invention does not have a structure in which a large volume (approximately 20,011>) of hot water is kept warm in a large volume (approximately 20011>) tank as in the past. It has a structure in which hot water is sequentially supplied to the desired temperature by rapidly heating the tank using the heat dissipation of the latent heat type M heating material and the M heat.Therefore, compared to conventional hot water storage tanks, the volume is reduced to 1/2. It can be reduced to 3 to 1/4.

However, there is no particular limit to its volume.

〔Effect of the invention〕

As described above, the solar water heater according to the present invention is equipped with a hot water storage tank above the heat collector, and water is naturally circulated between the two, and the solar water heater that supplies water to the lower part of the hot water storage tank is installed. In water heaters, the hot water storage tank has a built-in capsule containing a latent heat storage material that warms the supplied water, and hot water is supplied when the water level rises by 1. Because hot water can be quickly brought to the desired temperature in the hot water tank by utilizing the heat storage and heat dissipation of the latent heat storage material, the hot water storage tank needs to have a capacity to store the required amount of hot water in advance. The hot water storage tank can be downsized without the need for a hot water storage tank, and this has the effect of reducing the drop in temperature of hot water due to heat radiation from the surface of the hot water tank. Furthermore, by downsizing the hot water storage tank, it is possible to reduce the cost of materials and downsize manufacturing equipment.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a plan view and a sectional view of an embodiment of the solar water heater according to the present invention, respectively, and FIG.
FIG. 4 is a perspective view and a partially sectional side view, respectively, of an embodiment of a container containing a latent heat storage material constituting a solar water heater according to the present invention. 1... Heat collector 5... Hot water storage tank 9... Capsule
10... Latent heat storage material 11... Groove 12... Water supply pipe 13... Hot water supply pipe agent Patent attorney Takehiko Matsumoto (9) Figure 1

Claims (3)

[Claims] (1) In solar water heaters, a hot water tank is provided above the heat collector, and water naturally circulates between the two, and water is supplied to the lower part of the hot water tank, water is not supplied to the hot water tank. A solar water heater is characterized in that it has a built-in capsule containing a latent heat storage material that heats water, and hot water is supplied by raising the water level as the water is supplied. (2) The solar water heater according to claim 1, wherein the capsule has a large number of grooves over its entire surface. (3) The solar water heater according to claim 1 or 2, wherein the latent heat storage material has a melting point higher than the average maximum water supply temperature and lower than the average minimum temperature rise.