JPS59231360A - Excessive heat collection preventive type heat collector - Google Patents

Abstract

PURPOSE:To positively prevent excessive heat collection to a heat medium and also to prevent thermal deterioration of surface treatment having an excellent selective absorption by providing heat collecting fins made of a shape memory alloy in a communication pipe and performing coating treatment or painting on the front surface sides of the heat collecting fins by a surface treatment having an excellent selective absorpiton property. CONSTITUTION:Heat collecting fins 8 are provided in the communication pipe 1, and coating treatment or painting is applied on the front sides (a) of the heat collecting fins 8, by a surface treatment 3 having an excellent selective absorption, and a surface treatment 9 having a good reflectivity is applied to the back surface (b) of the heat collecting fins 8. As a material quality of the heat collecting fins 8, the shaped memory alloy is used, and the fins 8 are widened in a flat shape at a temperature which is less than a predetermined temperature tA, and at a temperature which is more than a predetermined temperature tA, the shape of the fins is designed to be changed to direct the surfaces subjected to surface treatment 9 having a good reflectivity toward the incidence side so that the both surfaces or only one surface of each fin covers the surface 3 subjected to surface treatment 3 having a good selective absorption. The heat collectors thus formed are accommodated in a casing 5 provided with a permeating member 4 having a good permeability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a solar heat utilization device that prevents excessive heat collection in a heat collector and takes measures against excess heat.

Conventional structure and its problems Conventionally, as shown in FIGS. 1 to 3, a heat collecting fin 2 is provided inside the flow pipe 1, and the surface of the heat collecting fin 2 is treated with a surface treatment having good selective absorption properties. Row 5, this is a heat collector 6 housed in a casing 5 equipped with 4 transparent bodies, so it collects solar heat, the heat collecting fins 2 rise in temperature, transfer the heat, and flow through the flow pipe 1. However, if there is a problem with the pump failure, the heat load is small, or there is a problem with the sensitivity of the temperature sensor, etc., the temperature of the heating medium 7 will rise and boil. When the temperature reaches tB or more, the pressure increases and a dangerous situation occurs. The temperature of the heat collecting fins 2 increases by 20% due to the surface treatment 3 with good selective absorption.
Surface treatment 3, which has good selective absorption properties, may deteriorate in performance when exposed to high temperatures of 0 to 300 degrees. Figure 4 shows all the lines where the temperature of the heat collecting fins increases depending on the amount of solar radiation.

OBJECTS OF THE INVENTION The present invention solves these conventional problems and reliably prevents excessive heat collection to the heating medium, and also prevents thermal deterioration of surface treatment with good selective absorption. The purpose of this tray was to prevent the production of grapes and to ensure long-term safety and quality maintenance.

Components of the Invention The present invention provides heat collection fins on the flow pipe, coats or paints the front side of the heat collection fin with a surface treatment with good selective absorption, and coats the back side with a surface treatment with good reflectivity. Eb1 Is the heat collecting fin made of shape memory alloy? It is something that was used.

Does this configuration prevent excessive heat collection and thermal deterioration of surface treatment? DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 5 to 7.

The external appearance of the structure is the same as that of the conventional example and is similar to that shown in FIGS. 1 and 2.

Heat collecting fins 8 on flow pipe 1? The front side a of the heat collecting fins 8 is coated or coated with a surface treatment 3 with good selective absorption, and the back side of the heat collecting fins 8 is coated with a surface treatment 9 with good properties. .

The material of the heat collecting fins 8 is a shape memory alloy.B1 is used at a constant temperature, for example, if water is used as the heat medium 7, 9 is used.
At a temperature of around 6 to 97°C, another heat medium 7 propylene glycol aqueous solution (depending on the concentration) heat collecting fusun 8 cover each other or only one side of each other with a surface treatment that has good selective absorption. The nine surfaces have been surface-treated to have good reflectivity, and their shapes are changed to the incident side.This is housed in a housing 5 equipped with four transmitting bodies with good transparency.

In the above configuration A, the heat collecting fins 8 that collect solar heat heat up and heat the heat medium 7 flowing inside the flow pipe 1 by heat transfer. Assuming that the temperature of the heat collecting fins 8 approaches a certain temperature tAvc such as the boiling point tB of the heat medium 7 due to some principle,
Made of shape memory alloy, the heat is reflected and collected by the highly reflective surface treatment, which prevents the temperature from rising. Is the temperature rise due to empty space or excessive heat collection in Figure 7? The temperature characteristics show the conditions that can be prevented. 5.a is FIG. 5, b is FIG. 6, and C is a conventional example. FIG. 8 shows another embodiment r, in which a heat insulating material 10 is incorporated on the back surface.

As described in detail, according to the present invention, 0) ■ Failure of the circulation pump of the heat collection system, @ power outage when the heat load side is too low, ■ In the case of sensitivity deviation of temperature sensor, setting deviation, etc. This can be prevented by changing the shape of the fins to the reflective surface without power when the temperature of the heat medium rises to reach above the boiling temperature and the pressure rises.

(Even in systems where the heat medium falls into water, preventing overheating can also prevent thermal deterioration of surface treatments with good selective absorption.

(3) There is no need to prepare a protective sheet for dry cooking during construction.

(Chrysanthemum: Can deal with excessive heat collection without using power.

(5) It can be safely left in place even during the off-season.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a conventional heat collector, Fig. 2 is a partially sectional plan view of a conventional heat collector, Fig. 3 is a sectional view taken along line A-A in Fig. 2, and Fig. 4 is a cross-sectional view of a conventional heat collector. Figure 5 is a cross-sectional view showing the normal state of an embodiment of the present invention; Figure 6 is a cross-sectional view showing the open operating state. Figure 7 is a diagram showing the temperature characteristics of the heating surface of the heat collecting plate. The dry cooking (during excessive heat collection) surface temperature characteristic diagram and FIG. 8 are cross-sectional views showing another embodiment of the present invention. 1... Distribution pipe, 2... Heat collection fin, 3
...Surface treatment with good selective absorption, 8...
・Heat collection fusun, 9...Surface treatment with good reflectivity.

Claims (1)

[Claims] A heat collector for preventing excessive heat collection, in which a flow pipe is provided with heat collecting fins made of a shape memory alloy, and the surface side of the heat collecting fins is coated or painted with a surface treatment having good selective absorption properties.