FR2679019A1 - Solar collector - Google Patents

Abstract

Heat energy-gathering solar collector with circulation of air or any other gas including a box structure 4 exhibiting an open face receiving at least one wall 1 which is permeable to solar radiation, walls 2 in the box structure constituting absorbers and a heat exchanger 3 built into the box structure and in which there flows a heat-transfer fluid which is heated by the air or any other gas subject to solar heating in the box structure. The collector according to the invention is essentially characterised in that inside the box structure, the absorbers 2 heated by the action of the solar radiation heat the ambient air and allow it to rise. The hot air passes through the absorbers and penetrates into the exchanger where it transmits its heat and falls to the base of the box structure. Losses due to convection and conduction between the absorber and the glazing of the solar collector may be reduced.

Description

 The present invention relates to a thermal collector solar collector with circulation of air or any other gas comprising a heat transfer air-fluid exchanger.

The sensor according to the invention is of the type consisting of a thermally insulated box having an open face receiving at least one wall permeable to solar radiation, for example made of glass.

In the box is arranged walls constituting heat absorbers and a heat exchanger in which circulates a heat transfer fluid which is heated by contact with air or any other gas subjected to solar heating in the box.

In the sensors currently used, the circulation of the heat transfer fluid takes place directly in the body of the absorber. The major drawback of such sensors lies in the fact that a non negligible part of the heat remains unused.

The sensor, object of the invention, obviates this drawback by the circulation of air inside the box and by the air through the absorbers.

According to a variant of the invention, the heat losses by convection and by conduction can also be reduced. The heat is thus released subject to air circulation.

The characteristics of the invention will appear on reading the description, with reference to the accompanying drawings in which - Figure 1 shows a sectional view of a simplified form of
embodiment of the invention, - Figure 2 shows a sectional view of another embodiment
of the sensor according to the invention, - Figure 3 shows a sectional view of an improvement of the
sensor according to the invention, - Figure 4 shows a sectional view of another 'perfectinnanent
of a sensor according to the invention.

- Figure 5 shows a sectional view of another improvement
of a sensor according to the invention.

- Figure 6 shows a sectional view of an alternative embodiment
of the sensor according to the invention.

 As shown in Figures 1 to 6, the sensor according to the invention consists of a box 4 preferably of rectangular parallelepiped shape comprising an open front face and a bottom and four sides, two longitudinal and two transverse.

 The walls of the box as defined are insulated anyway conne.

It goes without saying that the box is designed in one or more suitable materials in
so that the outer faces of its walls are weatherproof and
that the internal faces of its walls withstand in all circumstances the maximum temperatures that can be obtained there.

 The open face of the box is formed by an outer wall 1 made of a material permeable to solar radiation which can for example be made of glass or any other suitable material.

Absorbers 2 are mounted inside the box. The absorbers 2 will preferably be selective, that is to say capable of absorbing visible radiation and of retaining a large part of the infrared radiation.

The wall 13 is a wall permeable to solar radiation, for example glass or any other suitable plastic or synthetic material.

The wall 13 is a small wall piece placed in the box so as before the absorber near the upper edge of the adjoining box with two longitudinal sides and the upper edge of the box. The wall 13 can assist air circulation easily and reduce loss of convection.

the heat exchanger 3 is arranged for mounting the sensor according to the invention behind the absorbers.

The exchanger is mounted menlêre to occupy the entire ~ of the section between the absorbers and the bottom of the box to form a forced passage of the heat transfer gas.

The exchanger 3 is constituted for example by a coil n-i of flakes or any other suitable way, in which circulates a heat transfer liquid, for example water or oil or any other suitable liquid.

According to another characteristic of the invention, the exchanger may have an inlet or supply of heat transfer fluid 5 at its base and an outlet 6 in the high position.

The inlet 5 and outlet 6 pipes are in relation to a storage tank which is not shown.

Between the absorber and the lower internal edge of the box is a passage 11 for the circulation of air or any other gas contained therein.

Preferably, the passage 11 is of a size capable of promoting a
sufficient gas ciculation.

 It is therefore possible to proceed, as illustrated in FIG. 2 - 6, a coil 8 in which the same heat transfer fluid circulates in the exchanger, it is welded to the unexposed surfaces of the absorbers. The coil can constitute an inlet or supply of coolant at its base joined to the outlet of the exchanger with a tube 12 shown in Figure 6 and an outlet 10 of the coil in the high position.

In this form of use, the inlet 5 exchanger and outlet 10 pipes of the coil are in relation to a storage tank not shown in the sketch.

In this form of use, the heat transfer fluid first enters the heat exchanger heated by air, then enters the coil heated even more by the absorbers.

This shape can avoid a higher absorber temperature.

In FIG. 1, the sensor according to the invention is shown the absorbers 2 without a coil.

In FIG. 2, the sensor according to the invention is shown the absorbers 2 with the coil 8.

In FIG. 3, inside the box, on the open front face and parallel to the wall 1 can be mounted according to one embodiment a second wall 7 permeable to solar radiation and which can also be produced by glazing in glass or synthetic material or any other suitable material.

According to this embodiment, the walls 1 and 7 are separated by a gap providing an insulating air mattress.

 In Figure 4 is shown another improvement of the sensor according to llinuention.

 According to the improvement, a honeycomb device 9 is added.

 it is fixed against the inside face of floor 1. It is added to help further reduce convection and conduction losses.

In Figure 5 is shown a further improvement of a sensor according
the invention. It uses several torves which used according to the invention.

According to the form of realization of the type constituted by a box having
wall 1, on the inside face of wall 1 joined a device 9 in honeycomb, between the device 9 and the absorbers 2 is the wall 7
The device 9 and the wall 7 are used together to reach the high temperature and reduce losses by convection and by conduction.

The operation of the sensor as described in its preferred nonlimiting embodiments is as follows
The heat transfer gas, in this case air, for example, undergoes, as represented by the arrows, an upward movement in the intervals of the absorbers 2 passing through the absorbers 2 penetrating into the stretcher 3.

The absorbers 2 heated by the action of solar radiation heat the ambient air in the intervals of the absorbers 2 by allowing its ascent and penetration.

The hot air rises and enters the exchanger 3 releases its heat to the exchanger 3 descends at the base of the box. When the air passes through the passage 11, the other time air circulation can begin.

The air circulation works automatically without ventilation according to the thermosyphon principle.

The functioning of the air passing through the absorbers can reduce the heat losses by convection and by conduction.

The circulation of the heat transfer liquid is as follows
The heat transfer liquid enters the heat exchanger 3 heated by air, and then enters the coil 8 still heated by the absorbers in the cases of Figures 2 to 6.

When the heat transfer liquid reaches the temperature we need, the thermostat then causes a pump (not shown) to circulate the heat transfer liquid in the storage circuit (or network of use) and exchanger, the pump being supplied by electricity.

Claims (9)

 1) Solar collector of the type comprising a box 4 having a face  open receiving at least one wall 1 permeable to solar radiation1  a gas guide wall 13, absorbers 2, an exchanger 3 included  in the box and in which circulates a heat transfer liquid which is  heated by air or any other gas subject to solar warming  in the box, characterized in that the absorbers 2 heat the air  ambient by allowing its ascent and its penetration, in the exchanger  3 where it transmits its heat to the heat transfer liquid circulating in  the exchanger and goes down to the base of the box. 2) solar collector according to claim 1 characterized in that the  absorbers 2 can still heat the same heat transfer liquid  circulating in a coil 8 welded to the unexposed surfaces of  absorbers. 3) solar collector according to claim 1 or 2 characterized in that a  honeycomb device 9 is fixed against the inside of the  wall 1. 4) solar collector according to any one of the preceding claims  characterized in that it comprises a second wall 7 permeable to  solar radiation which is arranged parallel to the first wall 1. 5) solar collector according to any of claims 2 to 4 characterized  in that the absorbers are walls 2 arranged in front of the exchanger  3 and heated by the action of solar radiation, which heat the air  ambient and the heat transfer liquid in the coil 8 welded on the  unexposed surfaces of absorbers. 6) solar collector according to any one of the preceding claims  characterized in that the exchanger 3 is arranged in the section between  the absorbers and the bottom of the box so as to occupy the entire  of the section to constitute a forced passage of the heat transfer gas which  dropped his calories and went down to the base of the box. 7) solar collector according to any one of the preceding claims  characterized in that the supply of the heat exchanger with liquid  cold coolant is carried out in the lower part of it and that  the hot heat transfer liquid is removed at the top  of it. 8) solar collector according to any one of claims 2 to 7  characterized in that in the coil 8 welded to the surfaces  unexposed absorbers 2 circulates the same heat transfer liquid as  in the exchanger 3, a tube 12 connecting the outlet of the exchanger and  the inlet of the coil 8, the supply of the sensor with heat transfer liquid  cold takes place in the lower part of the exchanger and the evacuation of  hot heat transfer liquid carried out in the upper part of the coil. 9) solar collector according to any one of the preceding claims  characterized in that the wall 13 is a small wall disposed in front  of the upper and contiguous absorber with two longitudinal sides and  the upper edge of the box to help air circulation and reduce  loss of convection.