JPS608276Y2 - solar heat collector - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a solar heat collector using a heat pipe, and uses an inexpensive structure to prevent damage to the heat pipe due to freezing of the working fluid.

Generally, heat pipes are made by reducing the pressure inside the metal tube to remove water.
It is a heat transporter that uses alcohol, ketone, fluorocarbon, etc. as a working fluid and utilizes the latent heat of the working fluid, and a solar heat collector is constructed using this heat pipe.

By the way, in solar heat collectors using heat pipes, although the heat pipes are housed in a translucent outer tube, they are installed outdoors to collect solar heat, so they cannot be used outdoors at night during winter. When the temperature drops below 0°C, the working fluid freezes and its volume increases, causing the metal tubes that make up the heat pipe to be deformed from the inside due to expansion. If the deformation limit is exceeded, the metal tubes will break. do.

Therefore, in order to prevent the heat pipe from being damaged even if the working fluid freezes, it is conceivable to adopt a structure as shown in FIGS. 1 to 3.

Next, to explain the solar heat collector shown in the same figure, a heat pipe has heat collecting fins 2 thermally joined to a translucent outer tube 1 made of glass or the like, and a spherical liquid reservoir 3 is provided in the opening at the bottom. 4
is inserted, the opening of the outer tube 1 is closed with the stem 5, the upper part of the heat pipe 4 is guided outside through the stem 5, the inside of the outer tube 1 is evacuated, and the required amount is placed inside the low vacuum heat pipe 4. In addition, a capillary structure 7 such as a mesh or fiber is eroded by the working fluid 6 in the liquid reservoir 3 from the lower end of the heat pipe 4.

Note that 8 in the figure is a condensing section provided at the upper end of the heat pipe 4.

Then, solar heat is received by the heat collecting fins 2, the temperature of the heating part of the heat pipe 4 is increased, and the working fluid 6 in the heat pipe 4 is heated.
The temperature rises and evaporates, the vapor moves to the condensing section 8, where it releases latent heat to a circulating heat medium (not shown) and condenses, and the condensed liquid flows inside the heat pipe 4 due to gravity. The heat flows back to the original heating part along the wall surface, and the heat is collected by repeating the above action.

Even if the hydraulic fluid 6 freezes and expands its volume at night during winter, the volume of the fluid reservoir 3 is more than twice the volume of the hydraulic fluid 6, so the fluid reservoir 3 will not deform at all. , the heat pipe 4 will not be damaged.

Furthermore, since the working fluid 6 is unevenly distributed in the locally provided liquid reservoir 3, its evaporation area becomes small, but the capillary structure 7 facilitates evaporation of the working fluid 6 in the liquid reservoir 3.

As mentioned above, this device freezes the hydraulic fluid using an inexpensive structure that does not require a liquid reservoir with a volume larger than the volume of all the hydraulic fluid when it is frozen, and does not require a capillary structure in the fluid reservoir. The purpose of this invention is to provide a solar heat collector that can prevent damage to heat pipes caused by heat pipes.Next, this invention will be explained in detail with reference to the drawings from FIG. 4 onwards showing an embodiment of the invention.

First, in FIGS. 4 to 6 showing one embodiment,
The same symbols as in Figures 1 to 3 indicate the same things, and 9
is a spiral groove 10 formed in the tube wall of the heat pipe 4'.
The working fluid 6 that is condensed in the condensing section 8 and flows down is collected in each of the concave sections 9.

11 is a spherical liquid reservoir attached to the lower end of the heat pipe 4'.

Note that a recessed portion that fits into the upper part of the groove 10 of the heat pipe 4' is formed on the lower surface of the heat collecting fin 2'.

Therefore, the volume of the liquid reservoir 11 should be larger than the volume obtained by subtracting the volume of the hydraulic fluid 6 accumulated in each recess 9 from the frozen volume of all the hydraulic fluid 6, and the volume of the hydraulic fluid 6 shown in FIGS. The volume can be made significantly smaller than the volume of the reservoir 3.

In addition, when the heat pipe 4' is started, the working fluid 6' accumulated in each recess 9 first evaporates, and this vapor and the vapor condense in the condensing part 8 and become liquefied reflux liquid, and the liquid pool Since the temperature of the working fluid 6 of No. 11 increases and evaporation is promoted,
Start-up can be performed smoothly, and there is no need to provide the aforementioned capillary structure 7 or the like.

In addition, in the above embodiment, as a means for forming the recess 9,
Although the spiral groove 10 is formed because it is easy to manufacture, the present invention is not limited to this embodiment, and the recess may be formed only in the lower pipe wall of the heat pipe 4'. The shape may be formed into, for example, a semicircular shape, which has a depth smaller than its width and expands from the bottom toward the opening at the top.

Further, as shown in FIG. 7, if the shape of the liquid reservoir 11' is formed into a substantially inverted triangle, the volume can be further reduced.

That is, in the aforementioned spherical liquid reservoir 11, the volume needs to be more than twice the volume of the hydraulic fluid 6 excluding 6 parts of the hydraulic fluid collected in the recess 9, but if it is made into an inverted triangular shape, the upper Because it has a shape that spreads toward the liquid pool 11
It is only necessary to make the volume of the working fluid 6 slightly larger than the volume of the working fluid 6 excluding 6 parts of the working fluid accumulated in the recess 9.

As described above, according to the solar heat collector of this invention, in a solar heat collector using a heat pipe, a recess is formed in the tube wall of the heat pipe, and a recess is formed at the bottom end of the heat pipe to prevent the freezing of the working fluid. By providing a liquid reservoir with a volume larger than the volume obtained by subtracting the volume of the working fluid accumulated in the recess from the volume, damage to the heat pipe due to freezing of the working fluid can be reliably prevented with an inexpensive configuration.

[Brief explanation of the drawing]

Figures 1 to 3 show an example of a solar heat collector constructed using ordinary heat pipes and equipped with means to prevent damage to the heat pipes due to freezing of the working fluid. The figure is a cutaway side view, FIG. 3 is an enlarged view of a part of FIG. 2, FIGS. 4 to 6 show an embodiment of the solar heat collector of this invention, and FIG. 5 is a cutaway side view, FIG. 6 is an enlarged view of a portion of FIG. 5, and FIG. 7 is a cutaway side view of a portion of another embodiment of the invention. 4'...Heat pipe, 9...Recessed part,
11.11'...Liquid pool.

Claims (1)

[Scope of utility model registration request] In a solar heat collector using a heat pipe, a recess is formed in the tube wall of the heat pipe, and at the lower end of the heat pipe, the volume of the working fluid accumulated in the recess is subtracted from the volume of the working fluid when frozen. A solar heat collector with a liquid reservoir with a volume larger than the volume of the solar heat collector.