FR2514873A1 - Flat solar collector - using flat box made of cellular polymer, so collector has low wt. and may form channels through which heat transfer fluid is circulated - Google Patents

Abstract

The collector includes at least one box contg. an absorber, and at least one tube or sleeve through which a heat treans transfer fluid is circulated. The box has at least one cover, which is transparent to solar rays and has a "greenhouse" effect. The box is made of a cellular synthetic or polymer material (I) with a low thermal conductivity, and contains recesses which form tubes carrying the heat transfer fluid, or form zones in which such tubes can be located. The box is pref. made of polyurethane, and contains metal inserts used for reinforcement or fixing. The box is pref. coated by a protective foil which reflects heat. The resulting solar collector has a low wt. and can easily be fixed to a roof.

Description

The present invention relates to a flat solar collector.

This type of sensor is mainly constituted in a known manner by a chest or box by a cover wall transparent to solar radiation to create a greenhouse effect, by sheaths or conduits for circulation of a heat transfer fluid, arranged in the chest or box under the cover wall, provided with a black coating to absorb the heat effect of the solar radiation which they transmit to the heat transfer fluid.

These sheaths or pipes are generally formed between two sheets of metal plated against one another or by tubular elements associated with collectors.

Due to the design of the sheaths or conduits, the sensors of this type have a thermal inertia which reduces and delays the heat exchanges between the absorbent surface and the heat transfer fluid.

 To reduce heat losses at the ducts or pipes - the collectors are fitted with insulation means which significantly increases their cost without achieving the expected results.

It is also known that such sensors can be mounted on the roof of a building.

For this their technical characteristics must be so that they can easily bear the same loads as the roof.

To this end, the sensors of the prior art are reinforced at several points which increases their weight and therefore requires the reinforcement of the supports of the roof covering elements.

 It should also be noted that, for the installation of these sensors, a person skilled in the art must provide for the installation of a leak-proofing element different from that normally used by roofers.

The object of the present invention is to overcome the drawbacks previously stated by the use of a solar collector of increased efficiency, light and self-supporting and requiring only traditional means for its installation on the roof.

To this end, the sensor according to the invention is essentially characterized in that its trunk is formed by molding a synthetic or cellular plastic material: armed with low thermal conduction to isolate the sheaths or pipes for circulation of the heat-transfer fluid, to that it constitutes insulation between the building and the outside environment and so that it can support the same loads as the roof without reinforcing the frame.

According to another characteristic of the invention, the chest is made of polyurethane and receives a metal frame.

Other advantages and characteristics of the invention will appear on reading the description of a preferred embodiment with reference to the accompanying drawings in which - Figure 1 is a top view of the box according to the invention, - The Figure 2 is a cross-sectional view of the sensor according to the invention, - Figures 3 to 5 are respectively sectional views of the
box along the lines AA, BB, CC of Figure 1, - Figure 6 is a sectional view of a second embodiment
tion of the sensor according to the invention.

As shown, the sensor according to the invention comprises a box 1, at least one absorbent surface 2 or absorber, at least one sheath 3 or pipe for circulation of a heat-transfer fluid, at least one cover 4 transparent to solar radiation disposed at the above the absorbent surface to delimit therewith a chamber in which a greenhouse effect is created.

The box 1 is constituted for example by molding of a synthetic material or cellular plastic of low thermal conduction for example of polyurethane in order to constitute screen with the exchanges of heat between the building where it arises and the outside environment and to thermally insulate the sheaths 3.

The synthetic material of the box includes inserts constituting the frame and is distributed so as to provide recesses 1A constituting the sheaths 3 for circulation of the heat transfer fluid and / or constituting housings in a circuit of a heat transfer fluid.

According to a preferred embodiment, the box is rectangular in shape and its inserts are formed by an internal metal frame 5 embedded in its mass and by external ribs or slats allowing the fixing by stapling, nailing or other processes of the various elements of the sensor. .

As can be understood, these arrangements provide the sensor with good resistance and the latter can bear the same loads as the roof without risk of breakage.

In addition, the use of a plastic material makes it possible to produce a particularly light sensor, which eliminates the installation of a member for reinforcing the supports of the roof covering elements.

As can be seen from the attached figures, the box has peripheral ribs 6,7,8, and 9, of the same height arranged on either side of its thickness.

Parallel to its major axis, the box 1 is provided with at least one rib 10, of the same height as the others, also arranged on either side of its thickness.

Preferably this rib is constituted by a wooden slat
included in the manufacturing mold of the trunk before the injection of the plastic material.

As can be seen in fig.l, the sensor has two ribs 10 disposed with the ribs 6 and 8 at regular intervals and which delimit therewith on one side of the box the recesses or housing 1A.

The trunk and its ribs are coated with a protective sheet, preferably made of aluminum to avoid deterioration of the surfaces during an impact.

In addition, the purpose of this sheet is to reflect the heat radiation to protect the box from heat.

 A> -antagement, this sheet is arranged on the walls of the mold before the injection of the plastic so that after solidification it can adhere to the surfaces and ribs of the box.

As can be understood, this sheet constitutes an envelope enclosing the entire box, which contributes to its strengthening.

According to a first embodiment as shown in fig2, the sensor is more particularly intended to receive a gaseous heat transfer fluid, for example air circulating in the ducts formed by the elements 1A.

The absorber 2 according to this embodiment comes to rest on the ribs of the box and covers the recesses 1A.

The absorber 2 consists of a flat metal sheet and the sheaths or conduits 3 open into collectors 11 and 12 formed at the end of the sensor.

The absorber 2 preferably consisting of a thin aluminum sheet, has an absorbent face facing the sunlight and an emitting face directly in contact with the heat transfer fluid.

The black coating of the absorbent face is obtained by spraying a black powdery body and an agglomerate suspended in a resin transparent to solar radiation to adhere to the face of the absorber.

According to a preferred embodiment, the powdery body is graphite and the agglomerating soda ash.

The resin is advantageously constituted by an acrylic resin and the solvent by methylene chloride.

By way of indication only, graphite and sodium silicate are mixed with one another in a proportion of one to four.

These various constituents make it possible to form a particularly adherent coating on metal supports and therefore on the aluminum foil and having a particularly high absorbing power.

In addition, the absorber as described has the advantage of ensuring the transfer of heat between its absorbent face and the heat transfer fluid without loss and without any delay due to the thinness of the aluminum foil.

It should also be noted that the components of the coating make it possible to stiffen the aluminum sheet, which ensures that it is properly held between the ribs.

As said previously, the sheaths 3 receive a gaseous heat transfer fluid, for example air.

This fluid enters the sensor through two orifices 13 formed in the thickness of the collector 11 and leaves therefrom through an orifice 14 formed in the thickness of the collector 12.

As can be seen in fig.l, 4 and 5 these collectors are each constituted by a recess formed at the end of the paral housing sensor with ribs 9 and 7.

The manifold 11 is intended to distribute the air or the heat-transfer fluid entering the sensor through the orifices 13 in the various fervent sheaths 3
Preferably as can be seen in fig.4, the manifold 11 is formed by a recess having two hollow shapes 15 joined by a boss 16 opposite the longitudinal median axis of the box.

The inlet holes 13 are formed in the areas of the clearance having the smallest thickness or in its hollowest parts.

The manifold 12 is intended to channel the air circulating in the ducts 3 towards the outlet orifice 14.

For this purpose; the collector as can be seen in fig. 5 is formed by a hollow-shaped recess, the hollowest part of which is provided with the orifice 14.

Above the grooves 6,7,8,9, and 10, and on the absorber 2, the sensor is equipped with elongate elements assembled together to form a support for the cover 4 and to ensure the maintenance of the absorber 2 on the ribs.

Preferably, the cover, the elongated elements and the absorber are secured to each other by means of fasteners of any known type cooperating with the ribs of the trunk 1.

According to a preferred embodiment, the elongated elements are formed by wooden slats, but it goes without saying that we can prwoir elements in any other material of low thermal conduction
Advantageously, the transparent cover 4 is of the type of that having a double wall internally ribbed and made of plastic or synthetic material, this in order to lighten the sensor.

According to a second embodiment as shown in FIG. 6, the sensor is more particularly intended to receive a liquid heat transfer fluid, for example from a circulating batten in a circuit comprising at least one tube 3A mounted with an absorber 17, in one of the housings 1A.

These housings are reopened by the cover 4 to constitute a room in which a greenhouse effect is created.

In each of the housings 1A are arranged several positioning means 18 linked to the box of the absorber and of the sheath to keep them spaced from the walls of said housing and of the cover 4.

These positioning means, for example cleats, are made of a material of low thermal conduction, for example of wood, to avoid any heat exchange between the absorber (s) 17 and the walls of the housing 1A.

The absorber 17 is constituted by a metal plate shaped so as to present at least one longitudinal housing 19 rece before the tube 3A and two wings 20 on either side of said housing 19 arranged in the same plane parallel to the cover.

 The absorber and sheath assembly is fixed to the cleats 18 by the wings 20.

Preferably the absorber 17 is oriented so as to present a housing 19 facing the cover 4 or disposed between the tabs as can be seen in FIG. 6, but one can provide the opposite orientation consisting in placing said housing 19 above so-called cleats.

The housing 19 is shaped so as to substantially match the external shape of the tube 3 sized so as to ensure intimate contact with the said tube 3A along all or a portion of the periphery thereof.

As is understood in this case, the emitting face of the absorber is constituted in particular by the face of the housing.

The housing 19 is closed by a plate 21 in intimate contact with the tube 3A and the wings 17- to complete the heat exchange.

The spaces arranged between the sheath 3 and the housing 19 and the wall 21 are filled with a material 22 of high \ thermal conduction capacity which is in a powdery form preferably mixed with a high.

The purpose of this set of provisions is to ensure lossless heat exchange between the absorber and the heat transfer fluid conveyed by the tube 3A.

In addition, the thickness of the absorber is such that it allows all of the heat transfer between said absorber and the heat transfer fluid,
The black coating of the same type as that described above is placed on the faces of the wings and of the plate 21 facing towards the cover 4 and can also be arranged on the face turned towards the walls of the housing 1A to absorb the heat radiation reflected by the aluminum protective sheet.

According to a preferred embodiment shown in fig.6 the housing 19 has a semicircular shape extended towards the plate 21 by a rectangular elm to receive a tube 3A of circular cross section.

It goes without saying that the absorber can be shaped so as to receive tubes of polygonal cross section, for example square or rectangular.

According to this embodiment, the contact between the tube 3A and the housing 19 takes place along a half circumference and the contact between said tube and the plate 21 takes place along a generator.

The sensor as described may include an exchange r embedded in the mass of the box and associated with the circuit of the heat transfer fluid polIr to heat for example the water conveyed by the sanitary circuit of the building.

The sensor as described is of increased efficiency and its lightness allows it to be easily integrated into the roof.

In addition, such a sensor does not require any means of insulating the sheaths and / or the circulation tubes of the heat transfer fluid and constitutes a screen for heat exchanges between the building on which it is placed and the external environment.

 It goes without saying that the present invention can receive all arrangements and all variants without departing from the scope of this patent.

Claims (1)

 R1 / Solar collector comprising at least one box (1), an absorber  butter (2) at least one sheath (3) or circuit, in the box  circulation of a heat transfer fluid, at least one cover  ture (4) transparent to solar radiation arranged at the  above the absorber to define a room with it  in which a greenhouse effect is created, characterized in that  the box is made of plastic or plas  ticks with low heat conduction,  synthetic material includes inserts constituting the reinforcement  and that the synthetic material is distributed in a sort of mena  manage recesses 1A constituting the circulation sheath of a  heat transfer fluid and / or constituting housings 1A of  heat transfer fluid circuit. R2 / Solar collector according to claim 1 characterized in  that the inserts are made up of a metal frame  internal (5) and by external slats or ribs allowing  fixing by stapling, nailing and other process, different  rents elements. R3 / Solar collector according to claim 1 characterized in that  the box (1) consists of a polyurethane. R4 / Solar collector according to claim 1 characterized in that  the box (1) is covered with a protective sheet, to  avoid deterioration of its surface, able to reflect the  heat radiation to protect it from heat.  R5 / Solar collector according to claim 1 comprising an absorber  butter (2) consisting of a metal sheet whose face  turned towards sunlight receives a black coating  able to absorb the calorific effects of solar radiation  characterized in that the coating is obtained by spraying  tion of a powdery body and a suspended binder  in a resin transparent to dissolved solar radiation  in a soldier to adhere to the metal sheet.  R6 / Solar collector according to claim 5 characterized in that  that the powdery body is graphite, that the binder is  of sodium silicate, which the transparent resin is a rea  sine acrylic and that the solvent is methylene chloride.  R7 / Solar collector according to re ~ endication 1 including the housing  has at least one recess (1A) constituting the sheath  culation of a heat transfer fluid characterized in that the  said box comprises at least two manifolds (11) and (12)  in connection with at least one sheath (3) formed in its mass  to each extrbmitd, which the said collectors present to the  at least one recessed shape (15) and / or at least one recessed shape  projection (16) and that each hollow shape (15) corresponds  an inlet (13) or outlet (14) orifice for the heat transfer fluid  so as to distribute the said fluid in the sheaths or  to channel it towards the outlet orifice (14).  R8 / Solar collector according to claim 1, including the housing  carries at least one housing (17) to a circuit of a heat transfer fluid  carrier characterized in that the absorber (17) presents  less a longitudinal housing 19 receiving the tube (3A) conforms  mé and sized so as to ensure internal contact with 1  said tube along the whole or a portion of the periphery of it  1 this and two wings (20) on either side of said housing  (19), that said housing is closed by a plate (21) in  intimate contact with the wings (20) and the tube (3A) and that  the spaces between said sheath and the housing (19) and the  said plate (21) are filled with a conductive material ther  mique (22).  R9 / Solar collector according to claim 9 characterized in that  the housing 19 has a semi-circular shape.  towards plate t21) by a rectangular shape to receive  a tube (3A) of circular section. R10 / Salt sensor according to claims 1 and 9, characteris6  in that it comprises at least one exchanger embedded in the mass  of the box through which a pipe (23) associated with the sheaths passes  (3) and provided with a fluid inlet and outlet port  heats up in contact with said pipe. R11 / Solar collector according to claims 1 and 9 characterized  in that it comprises at least one exchanger, embedded in the  mass of the associated box. to the fluid circulation circuit  coolant.