FR2535034A1 - Heat generator using solar energy and application to a refrigeration installation. - Google Patents

Abstract

Energy production. The generator comprises: a cylindro-parabolic reflector 2, a framework 1 for supporting the reflector, a heat duct 3 supported by the framework, a sleeve 16 for fixing and for thermal conduction between the upper end portion of the heat duct and an apparatus for transforming the thermal energy supplied. Application to generators of the absorption type.

Description

 The present invention relates to the general technical field of solar energy and it aims, more particularly, that of the direct production of thermal energy as opposed to that of the transformation of solar energy into electrical energy.

 In the technical field above, we have already proposed a large number of solutions for producing thermal energy by transformation of solar energy.

 The devices, generally used and called "sensors" in the art, can be static or dynamic, that is to say program or automatic tracking. These devices all generally include a circulation circuit for a heat transfer fluid responsible for taking thermal energy from the sensor and transferring it to the device for use or transformation. Such a fluid can between, in particular, water or oil.

 These devices are generally satisfactory for a large number of applications, although their performance does not make it possible to apply a relatively high temperature to the use or processing apparatus, taking into account the operating conditions of the circulation system and the nature of the fluids used.

 In certain applications, these conditions are prohibitive, because the operating principle of the apparatus for use or transformation implies a relatively high temperature within a hot source of relatively small volume.

 This is the case, in particular, of refrigeration installations comprising a system for producing frigories operating on the basis of the principle of absorption, as opposed to the system operating by compression.

 The object of the invention is to solve the general problem thus posed by proposing a new solar-powered heat generator having a source of heat production at a relatively high and constant temperature throughout the duration of exposure of the generator to solar radiation. under an angular range of incidences considered to be usual for sensors in the general sense.

 Another object of the invention is to provide a heat generator, of robust and reliable design, not requiring the intervention of personnel specially qualified for its maintenance.

 An additional advantage of the object of the invention is to provide a heat generator which can be produced industrially at an attractive cost price.

 An additional object of the invention is to provide a solar-powered heat generator, more particularly suitable for supplying the heat necessary for the operation of refrigeration appliances, of the absorption type.

To achieve the above goals, the heat generator according to the invention is characterized in that it comprises
- a cylindro-parabolic reflector,
- a reflector support frame giving
the focal axis of the latter an angle of inclination
its adjustable with respect to the horizontal,
- a heat pipe supported by the frame and centered on
the focal axis,
- a ther adapter and conduction sleeve
mique between the upper terminal part of the calo
duke outside the frame and a
transformation of the thermal energy supplied
by the generator.

 The invention also relates, as a new refrigeration installation, to an installation comprising a refrigerator of the absorption type and a heat generator according to the invention, installation in which the upper part of the heat pipe is associated, by a sleeve of adaptation and thermal conduction, to the boiler of the refrigerator.

 Various other characteristics will emerge from the description given below with reference to the accompanying drawings which show? by way of nonlimiting examples, embodiments of the subject of the invention.

 Fig. 1 is a perspective, partially broken away, of the solar energy heat generator according to the invention.

 Fig. 2 is a sectional elevation, partly broken away, showing, in a partial way, on a larger scale, certain details of the embodiment of the object of the invention.

 Fig. 3 is a schematic view illustrating a preferred example of application of the object of the invention.

 your fig. 4 is a cross section taken substantially along the line IV-IV of FIG. 3.

 Fig. 5 is a section, similar to FIG. 4, but illustrating an alternative embodiment.

 The solar powered heat generator, shown in fig. 1, comprises a frame 1 supporting a cylindro-parabolic reflector 2 whose concave face, oriented to receive the solar radiation, is treated to have a good reflection index. The reflector 2 can be produced in many different ways and consist of a metal sheet or, alternatively, of a plastic sheet having a reflective coating attached to its concave face.

 The generator also comprises a heat pipe 3 carried by the frame 1, so as to occupy substantially the focal axis of the reflector 2. The heat pipe 3 and the reflector 2 can be carried directly by the rigid frame 1 or, preferably, be adapted, as illustrated in fig. I, on an intermediate structure constituted by a pivoting chassis 4 capable of being adjusted in angular orientation relative to a geometric axis x-x 'coinciding with the axis of the heat pipe 3.

 In this preferred embodiment, the chassis 4 is formed by a structure made of any suitable material, preferably removable. The chassis 4 comprises, at the upper part of its transverse sides 5, two bearings 6 which are mounted with the possibility of rotation on two bearing surfaces 7 presented by the frame 1.

The bearings 6 are preferably associated with members 8 for adjusting the angular position of the chassis 4 relative to the axis x-x '. By way of example, the members 8 are formed by clamping means 9, such as screws, carried by the bearings 6 and staging in peripheral grooves 10 formed in the bearings 7. It must be considered that any means equivalent technique, capable of mainly assuming an angular immobilization function and of adjusting this position of the chassis 4, can be substituted without departing from the scope of the invention.

The frame 1 comprises, whatever its embodiment, means 12 making it possible to adjust the angle of inclination
OC of axis xx 'with respect to the horizontal. In the case of embodiment according to FIG. 1, these means 12 are, for example, constituted by a telescopic base 13 adapted to one of the supporting uprights of the frame 1 and by a pivot axis 13 provided at the upper part of the second upright, as illustrated in FIG . 2.

 The heat pipe 3 is supported by the frame 1, so as to comprise an upper end portion 14 extending outside the frame 1 to cooperate with an apparatus 15 for using or transforming thermal energy. The cooperation between the upper end portion 14 and the device 15 is ensured by means of a sleeve for adaptation and thermal conduction 16, preferably consisting of two relatively removable half-shells 16a and 16b. In general, the half-shells 16a and 16b are made of heat-conducting material and can comprise, on their convex face, a layer of conductive material at the bottom which allows intimate surface contact to be established, promoting maximum thermal conduction. .

 As a general rule, one of the half-shells is adapted and fixed, under conditions of maximum thermal conduction, to the use or processing apparatus 15.

 The end portion 14 is preferably delimited by a rectilinear portion of vertical orientation extending beyond a bend 17 in an orientation, generally greater than 900 relative to the heat pipe. This end portion 14 can be shaped to extend immediately after the corresponding bearing 6 or, on the contrary, be distant from the latter by a variable axial measurement depending on the conditions of use. In the latter case, the part of the heat pipe, between the terminal part 14 and the corresponding bearing, is associated with an insulating coating 18, possibly supplemented by a tight protective sheath.

 According to another constructive characteristic of the invention, the heat pipe 3 is adapted in the bearing surfaces 3 by insulating sleeves 19, for example made of asbestos fabric.

The sheath 19 is through with regard to the range 7 corresponding to the upper part of the heat pipe, while the sheath 19 relating to the lower part is constituted in the manner of a nozzle, as shown in FIG. 2.

 The heat pipe 3 carries an absorbent coating 20, for example, consisting of a layer of black product, for example nickel oxide.

 According to a preferred arrangement, the active part of the heat pipe 3, extending between the bearings 6, is associated with a transparent tubular envelope 21 surrounding it concentrically at a distance to delimit an annular interval 22 closed by the sleeves 19. This interval contains a insulating air mattress assuming, with the envelope 21, a function of protection and thermal insulation of the active part of the heat pipe against the harmful influence of the ambient temperature or local winds likely to reduce the transformation of energy solar thermal energy. The envelope 21 is preferably constituted by a glass tube held concentrically with the heat pipe 3, being engaged in annular housings 23 presented by the opposite faces of the bearings 6.

 The arrangement illustrated by-fig. 2 allows to consider that the heat pipe 3 is maintained in a determined position or orientation, by the sleeves 19, while the frame 4 and the glass tube 21 can be moved in relative rotation during the angular orientation.

 The heat generator described above is oriented so as to benefit from optimal incident radiation reflected on the heat pipe. The active part of the heat pipe is subjected to a temperature rise producing the phase change of the internal liquid fluid which it contains. In a known manner, the developed vapor phase rises to the terminal part 14 representing a source of exchange where is carried out, by transfer of calories, the condensation of the internal fluid caused to descend into the active part to undergo a new change of state, under the effect of the solar energy concentrated by the reflector 2.

 The heat transferred in the terminal part 14, by the condensation of the internal fluid, is transmitted by the sleeve 16 to the apparatus 15 for use or transformation.

 By the means according to the invention, it becomes possible to have, locally, at the terminal part 14, a hot source of relatively high temperature, establishing itself above 1500 ° C. for the entire duration of a exposure of the reflector 2 to incident solar radiation striking it at an angle at least equal to 30 relative to sunrise and sunset.

 Fig. 3 shows an example of application of the heat generator to the constitution of a refrigeration installation including a refrigerator 24, of the absorption type. In this example, the end portion 14 of the heat pipe 3 is adapted, via the sleeve 16, directly to the boiler 25 of the refrigeration circuit. In this example, the boiler 25 represents the apparatus 15 of the example according to FIG. 1.

 Fig. 4 shows that it is advantageous to constitute the half-shell 16a directly by a conformation of the wall 26 of the boiler 25 and to provide, on this wall and on either side of the local conformation, means 27 for-l removable adaptation of the half-shell 16b. In such a case, the half-shell 16b is produced in the form of a laminated or sandwich element including a layer 28 of conductive material and a coating 29 of insulating material making it possible to reduce the loss by radiation.

 A layer 30 of deformable conductive material is preferably associated with the conformation of the wall 26, in order to establish, in all cases, an intimate surface contact, promoting conduction, whatever the degree of possible tightening of the members 27 or the surface deformations likely to occur.

Such a material also makes it possible, optionally, to compensate for faults in the adjustment of the relative inclination between the axis of the heat pipe 3 and the vertical orientation of the boiler 25.

 The implementation of the means of the invention, in an application of the above type, makes it possible to apply to the boiler 25 a temperature sufficient to cause its continuous operation by producing only a localized development of heat, thus making it possible to optimal refrigerator operating conditions 24.

 Another advantage of the installation in accordance with the invention lies in the possibility of rapidly mounting or dismounting the generator and the refrigerator 24, since it suffices to release the half-shell 16b to obtain either their integration or their physical separation.

 Fig. 5 shows that, in an application example such as above, it may be advantageous to make the terminal part 14 of the heat pipe cooperate with the boiler 25 by providing for the interposition of an accumulator 31. According to an exemplary embodiment, The accumulator 31 is constituted by a capacity 32 brought, with any suitable baleen, on the boiler 25, so as to establish good thermal conduction. The capacity 32 contains a heat transfer fluid 33, for example consisting of oil.

At least one heat exchanger 34 is provided for permanently immersing in the fluid 33 and being simultaneously in relation to the fluid of the boiler 25.

 An insulating coating 35 is attached to the capacity 32 to give the accumulator 31 conditions for maximum heat conservation.

 In the example according to fig. 5, the heat, yielded at the level of the part 14 by the condensation of the heat pipe fluid, is transmitted, as before, to the fluid 33 which ensures a certain accumulation thereof, as well as a conduction by the exchangers 34 to the fluid of the boiler 25 This arrangement makes it possible to confer a practical operating time greater than that during which the generator of the invention is capable of producing thermal energy in direct relation to the incident solar radiation received.

 The heat exchangers 34 are not illustrated, in FIG. 5, as an example and must be considered as being capable of being replaced by any technical equivalent capable of performing the same function.

It can also be provided to produce the accumulator 31 so that the front wall 32a can pivot on an articulation with a horizontal axis, provided substantially in the plane of the bottom of the capacity 32. Adjustment means are interposed between the capacity 32 and the wall 32a to give the latter a determined inclination. Seals are provided to allow a tight pivoting of the wall 32a. In this way, it becomes possible to adjust the inclination of the wall 32a in a manner complementary to the value of the angle CL and, consequently, to use a single type of angled heat pipe, whatever the latitude of implantation.
The invention is not limited to the examples described and shown, since various modifications can be made thereto without departing from its scope.

Claims (10)

CLAIMS:  1 - Solar energy heat generator, characterized in that it comprises  - a cylindro-parabolic reflector (2),  - a frame (1) for supporting the reflector providing  at the focal axis of this latter an inclination angle  naison (Ct) adjustable with respect to the horizon  tale,  - a heat pipe (3) supported by the frame and centered  on the focal axis,  - an adapter and conduction sleeve (16)  thermal between the upper terminal part of the  heat pipe outside the frame and an appliance  transformation of the thermal energy supplied  by the generator.  2 - Heat generator according to claim 1, characterized in that the heat pipe (3) is supported by the frame by being mounted in two bearing surfaces (7) with the interposition of insulating sleeves (19).  3 - Heat generator according to claims 1 and 2, characterized in that the heat pipe (3) is mounted in two bearing surfaces cooperating with two bearings (6) provided at the upper part of the two transverse sides (5) of a pivoting frame (4) carrying the reflector (2), these bearings being provided with members (8) for adjusting the angular position of the chassis with respect to a geometric axis coinciding with the axis of the heat pipe.  4 - Heat generator according to one of claims 1 to 3, characterized in that the heat pipe (3) is associated with a transparent tubular casing (21) surrounding it concentrically at a distance.  5 - Heat generator according to one of claims 1 to 4, characterized in that the heat pipe (3) has a high elbow end portion (14) associated with a sleeve (15) consisting of two removable half-shells (16a- 16b).  6 - Refrigeration installation comprising a heat generator according to one of claims 1 to 5 and a refrigerator (24) of the absorption type and in which the upper part (14) of the heat pipe is associated by the sleeve (16) to the boiler (25) from the refrigerator.  7 - Refrigeration installation according to claim 6, characterized in that the sleeve (16) consists of a half-shell formed by the wall of the element of the refrigerator and provided with a deformable conductive mass (30) and by a demountable complementary half-shell (16b) comprising on its external face a coating (29) of insulating material.  8 - Refrigeration installation according to claim 6, characterized in that the upper end portion (14) of the heat pipe is associated with the boiler with the interposition of a thermal accumulator (31).  9 - Refrigeration installation according to claim 8, characterized in that the accumulator 31 is constituted by a capacity (32) intermediate between the boiler (25) and the upper end portion (14), this capacity containing a heat transfer fluid (33 ) in which bathes at least one transfer exchanger (34) in relation to the fluid of the boiler.  10 - Refrigeration installation according to claim 8 or 9, characterized in that the accumulator comprises, for association with the upper end portion of the heat pipe, a wall capable of pivoting with sealing on a horizontal axis located substantially in the plane of the bottom of the accumulator, means for adjusting and immobilizing in the pivoted position being provided between the wall and the accumulator.