JPS59157440A - Underground heat storage system - Google Patents

Abstract

PURPOSE:To provide the underground heat storage system which is capable of reducing energy loss in a heat collecting section or a heat transporting pipe and elevating the temperature of an underground heat storage section by a method wherein sunlight energy is transferred underground as it is and then the energy is converted into thermal energy. CONSTITUTION:The sunlight 1 is caused to reflect on a plane mirror 8 of 3m in diam. and the reflected light is applied on a spot condensing type parabolical mirror 9 in parallel relationship with the optical axis of the latter. Then the sunlight is applied into the ground through a focussing point 10. In this case, a conical hole 11 is drilled in the ground so that the sunlight is directed to the heat collecting section 12 therethrough. The heat collecting section 12 is blackened so that it absorbs the sunlight well. The sunlight thus absorbed is converted into heat which is then transmitted to the soil around the heat collecting section so that the temperature in the ground is elevated and the heat is stored in the ground in the state of thermal energy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an energy storage system using sunlight as energy source, and particularly to an energy transport system suitable for underground heat storage.

[Prior art]

A conventional example of underground heat storage method is shown in Figure 1. Sunlight 1 is collected by a condensing parabolic mirror 2, and the solar energy is converted into thermal energy by a heat collection tube 3 placed on the focal point of the parabolic mirror. A liquid such as water or Freon is usually used as a heat medium in the heat collecting tube.

The heat medium whose temperature has been raised in the condensing section is transferred to the heat exchange section 6 through the piping 5 by the driving force of the pump 4.

In underground heat storage, the heat exchange part is naturally underground 7, and piping is laid in the area where heat storage is desired. Therefore, the solar energy carried by the heat medium is transmitted underground through the pipe wall to the soil and stored as underground thermal energy.

However, the conventional method has the following drawbacks.

(1) Energy loss in the heat collecting tube is large.

(2) Energy loss in the thermodynamic pipe is large.

(3) The temperature of the heat storage part cannot be kept high.

(4) The cost of piping and pumps is high.

(5) Difficult to transport energy over long distances To solve these problems, it is desirable to develop an inexpensive underground heat storage method with less energy loss.

[Purpose of the invention]

The purpose of the present invention is to develop an underground heat storage method that can reduce the energy loss in the heat collection section and heat transport piping, which is a drawback of the conventional underground heat storage method, and increase the temperature of the underground heat section. It is about providing.

[Summary of the invention]

The difference from conventional underground thermal storage systems is that the light energy from the sun is transported underground as light without being converted into thermal energy, and is first converted into thermal energy here.

As a result, energy loss during conversion from light to heat and energy loss during heat transport, which was impossible with conventional underground thermal storage methods, is eliminated, and as piping and pumps are no longer required, costs can be reduced. In the method, the temperature of the heat storage part is restricted by the temperature of the heat collection part, and it is desirable to make it high temperature, but according to the method of the present invention, there is no such restriction and the heat storage part can be easily raised to a high temperature.

[Embodiments of the invention]

An embodiment of the present invention will be explained below with reference to FIG.

Sunlight 1 was reflected by a plane mirror 8 with a diameter of 3 m, and was made incident parallel to the optical axis of a point condensing type emissive mirror 9 with a diameter of 3 m. release
Light incident parallel to the optical axis of the proboscis mirror passes through a focal point 10 and enters the ground. A conical hole like 11 is made in the ground,
Directs sunlight to the heat collecting section 12. 1. The inner heating part has become a black body to improve light absorption.The light absorbed by the heat collecting part is
It is converted into heat and transferred to the surrounding ground, raising the temperature underground and being stored in the form of thermal energy. In addition, a temperature increase of 200 C was observed in the five devices in which the open part of the earth's surface was the focus position of the parabolic mirror where sunlight was most concentrated.

In addition, in the conventional example, when water was used as a heat medium, the temperature rose by 50C. In Figure 3! However, according to the present invention, unlike the conventional and unreached systems, there is hardly any decrease in the heat exchange efficiency even if the temperature difference between the temperature of the port heating section and the atmospheric temperature becomes large. This phenomenon is due to the fact that in the conventional example, heat loss from the heat collecting tube exposed to the atmosphere was extremely large.

As described above, according to this embodiment, energy loss in the heat collection 'q and heat transport piping can be reduced, and the temperature of the heat storage section can be increased by 7.
It can provide an underground heat storage system.

FIG. 4 shows another embodiment of the present invention, which differs from FIG. 2 in that the heat collecting section 13 is a reflecting mirror and the M exchange area is enlarged. Therefore, with the same light intensity, the temperature during -fI heat will decrease, but all the light energy can be fully absorbed,
Total energy emission Wk from the optical path to the upper atmosphere, b-
I'm going to take a look. In the figure, a glass plate 14 is further provided for heat insulation in the optical path between the underground and the atmosphere. Note that this heat insulation effect is also effective in the embodiment row shown in FIG.

Figures 5 and 6 show the application of the present invention.

The difference from Fig. 2 is that the condensed light is not transported through the atmosphere and directly into the ground, but instead is transported into the ground through an optical fiber or light guide 15, etc.
The point is that it can be omitted. FIG. 6 describes an example in which the heat collecting portions in FIG. 5 are divided into fractions. According to this application 1+l, the position 1 force IA of the light collecting part and the heat collecting part can be freely selected, and the energy transfer of the long 1 ton female is also an IJT function.
It also has great practical effects.

In the above implementation example, a point-concentrating parabolic mirror was used as a condensing device, but if a line-concentrating parabolic mirror or a Fresnel lens has the function of concentrating sunlight, , nothing impairs the effects of the present invention.

[Brief explanation of the drawing]

Figure AA1 is a schematic diagram of the conventional underground heat storage system, Figure 2 is a schematic diagram of the underground heat storage system of the present invention, and Figure 3 is the outline diagram of the underground heat storage system of the present invention! #
The notes, FIGS. 4, 51, and 6 are diagrams showing a second modification and an applied example of the present invention. 1...Sunlight, 2...#! Glowing parabolic mirror, 3-・
- Heat collection pipe, 4... Pump, 5... Piping, 6... Replacement section, storage, 4 area, 7... Underground, 8... Top surface, 9... Point condensing type number/rostral obtuse, 10...focal point, 11
... Conical hole provided in the pond, 12.13 ... Heat collecting section, 14 ... Glass plate for heat insulation, 15 ... Glass fiber and light guide. $1 Prisoner 2 Fig. 2 茅 3 solid igIL prisoner difference (tea heat section temperature - popular temperature Fig. 4 悌 5 Fig.

Claims (1)

[Claims] 1. An underground heat storage system characterized by having a light condensing means, a means for conveying the condensed light underground, and a means for storing light energy. 2. Claim 1, characterized in that the optical path cross section of the light entering the ground is minimized at the opening in the ground by the means for conveying the collected light into the ground. Pond heat storage method. 3. In the first paragraph of the patent claim, it is a feature that the above-mentioned means for conveying the focused light underground is equipped with a device such as a glass fiber or a light guide that can freely change the optical path. Underground heat storage method.