FR2568991A1 - Solar power station - Google Patents

Abstract

The invention relates to a device for collecting and storing solar power with a small land requirement. According to one characteristic of the invention, the solar energy receiver and concentrator elements are disposed in a sealed cylindrical enclosure 1 with a vertical shaft forming a tower whose walls are constituted by transparent plastic materials. The cylindro-parabolic concentration device with vertical generatrices 2 is designed to be able to pivot around a hollow pylon 3 forming the rigid vertical shaft of the tower whose base forms the technical room and the thermal store.

Description

 The invention relates to an autonomous solar collection and storage device with a small footprint.

It is known that, in clear sky climates in particular, the solar energy capture devices making it possible to "follow" the sun have annual and daily yields higher than those of the fixed devices. To date, however, orientable devices are little used since they are clearly more expensive, fragile and sensitive to bad weather. It has been proposed in the art to place the orientable receivers in enclosures transparent to solar radiation, such as greenhouses or hemispherical inflatable enclosures; however, these installations generally require large areas of land in relation to the useful receiving area
The object of the invention relates to a simple device of small horizontal size, constituting a unit for exploiting solar energy.

 According to a characteristic of the invention, the solar energy receiving and concentrating elements are placed in a sealed cylindrical enclosure with a vertical axis forming a tower whose walls are made of materials transparent to solar radiation.

 According to another characteristic, the solar energy reception and concentration device designed to be able to rotate around a hollow pylon forming a rigid vertical axis of the device in order to automatically position itself facing the sun throughout each day. This arrangement allows a maximum theoretical capture duration and an almost constant energy reception for implantation latitudes close to or greater than 300.

 According to another characteristic, the transparent envelope and its frame are stabilized and braced, not only by the axial pylon extending from top to bottom, but also by the mass of a thermal storage or of a technical room with which it is associated, and which constitutes a seat and a recess in the ground.

 According to another characteristic, the cylindrical or polygonal shape of the entire power plant gives it a minimum wind resistance and allows almost constant reception of solar radiation whatever the time of day.

 The realization of a solar power station according to the invention could call upon metallic reinforcements coated with transparent plastic materials, constituting "working coating" of aeronautical construction type leading to light constructions which could be erected in one piece, sealed on the base forming technical room and possibly guyed in very windy sites.

 The materials receiving, concentrators and converters of solar energy incorporated could preferably be: solar cells in ribbon on flexible support, sheets of metallized plastic stretched on curved frames, fixed vertical tubular insulators enveloping the central pylon.

 The axial pylon could be produced by a metal tube serving as a draft pipe for a system for producing hot air or constituting the chimney of a back-up device for storable fuel.

 The means ensuring the orientation movements may be small electric motors or a clockwork system driven by weight reduction, or any other device.

 The installation according to the invention may possibly be carried out by independent stages, allowing horizontal connections between the outer envelope and the axial pylon.

 The receiving elements may be made up of articulated louvers making it possible to optimize the reception of solar radiation at height.

 Incidentally, the installation according to the invention could serve as a support for public lighting and a collective television antenna.

 The device according to the invention is particularly suitable for areas of dense habitat at low height where it can easily find place in restricted public or private spaces.

 The device is suitable for heating heat transfer fluids and for the production of cooling and electrical energy for groups of dwellings and agricultural or industrial installations.

 The invention will appear more clearly with the aid of the description which follows, given with reference to the appended drawings, and giving by way of example an embodiment.

 The installation, is established, for example, in a region of the 38th parallel enjoying an annual sunshine of 2,000 hours and intended for heating, refrigeration and the production of domestic hot water of a dozen well insulated houses . In this case, the installation will have to produce around 50,000 KW / hour thermal in order to save around 70% of the energy required.

In this case, the heating plant will have a surface for reflecting solar energy of around 120 m2, which will be obtained by a heating plant 6 meters in diameter and 20 meters in height.

 Figure 1 shows in front view and in vertical section with cutaway a device designed according to the invention and detailing in particular the reflector and the rotation device.

 Figure 2 is a horizontal sectional view from above of a current section of a device according to the invention, indicating in particular an embodiment of the vertical linear focus of the parabolic reflector and the transparent envelope.

 Figure 3 is a variant of the reflector device.

 FIG. 4 is a cutaway vertical section established in the median plane of the reflector and of the vertical hearth, and detailing the fluid circuit and the arrangement of the materials for exploiting the solar heat of the thermal storage and of the auxiliary boiler.

 We will first refer to Figures 1,2 and 3, in which we have shown the general configuration of an installation having the shape of a cylindrical tower with a circular or polygonal base, consisting for example of three distinct stages: , from bottom to top, the underground storage stage 1, the stage forming technical room 2, the stage forming the capture of solar radiation proper 3. According to the invention, stages 1 and 2 are real for example in concrete masonry or in metal contruction, stage 1 constituting thermal storage being carefully insulated and able to be compartmentalized in one or more tanks.

 Stage 3 is composed of a transparent enclosure 4 rigidified on its axis by a tubular pylon secured to the base that the technical room forms. This tubular pylon 5 serves as a support for tensioners 6 suspending a rigid ring 7 on which are assembled peripheral tensioners 8 anchored in the base formed by the technical room 2.

 It can be understood that such a self-tensioning structure constituted by the compressed axial pylon and by the tensioners forms an extremely rigid bracing structure making it possible to suspend a series of rings forming horizontal circular beams 9, and which will make it possible to screw on the transparent covering plates, for example of the plexiglass type which advantageously constitutes the vertical walls and the roof of the enclosure 4.

 Stay cables such as in 10 allow a safety bracing. There is shown a rotating reflector 11 cylindrical and elongated in the vertical direction; with an opening area of approximately 100 square meters.

 This reflector 11 is made of plastic sheets, metallized canvas or by a plurality of vertical polished strips.

 The reflector 11 thus constitutes a kind of sail, suspended from a yard 12 having the desired profile, and articulated to the tubular pylon 5 by means of a rotating bracket 13 comprising an annular turret 14 equipped with support rollers 15, and rollers guide 16.

 The drive of the assembly is carried out by an electric motor 17; a reduction gear 18, a pinion 19 and a ring gear 20.

 The drive device could also be a friction device.

 The acquisition and tracking of the sun is carried out by an optical illumination control device constituted for example by diodes or photocells 21-22, intended to control the orientation motor.

 In order to increase the efficiency of the reflector, and to reduce the optical losses at its low openings, the entire floor 23 is covered with a reflective surface 24.

 The good optical quality of the concentrator (reflector 11) is obtained by means making it possible to avoid local folds or deformations, and to allow free expansion under the effect of heat or significant cooling.

 To achieve this objective, the sail forming the concentrator (11) marries the upper horizontal curved yard (12) which constitutes the director of the cylinder thus formed.

 According to the invention, the sail is kept under longitudinal and vertical tension by a set of weights 25 whose traction effects are distributed uniformly by flexible and elastic horizontal slats 26, bent by fine cables 27 forming cords, and allowing the maintenance from the profile to the desired camber identically over the entire height.

One could advantageously use along the high yard or the low end batten, spring fasteners making it possible to compensate for the differential voltages.

 Is shown in vertical section in Figure 1, and in horizontal section in Figures 2 and 3, the constitution of the receiving hearth 28 designating a vertical solar boiler 29, enveloping the tubular axial pylon 5; and made up of a plurality of vertical tubes with metallic fins and coated with a selective treatment of the chrome, black for example type.

 The receiving surface of the boiler or "black body" is isolated on the rear face by a material 31 and separated from the interior atmosphere by a transparent envelope 32 which can be, for example, Pyrex glass, making it possible to minimize heat losses - in particular at high temperatures - by confining superheated air.

 Obviously, other types of embodiment are possible without departing from the scope of the invention.

We can for example achieve the general envelope in the form of a "bead" inflatable under pressure, or by assembling rigid, self-supporting ribbed plates.

 The rotating reflectors may be made of ultralight rigid material, cellular plastic, or composite honeycomb, etc., coated with reflective material.

In this case, the movable reflectors can be articulated at two points.

 The receiving focus can be achieved by helical winding of pipes; or - in the case of an air sensor made of corrugated, grooved or folded sheet metal with a very large exchange surface.

 Referring to Figure 4, which shows the entire installation, there is shown more particularly the thermal device. We can appreciate the compactness of the planned arrangements, as well as the shortening of the pipes allowing high yields, and a great economy of means.

 The receiving hearth 28 receiving direct and reflected solar radiation, is irrigated in a closed loop by a heat transfer fluid of the "gilotherm" type, and circulated by a pump 33.

 The loop being equipped with 2 exchangers 34 and 35 making it possible to supply the calories of an absorption refrigeration unit 36 or of a thermal storage 1 carefully insulated, and preferably buried to minimize heat losses.

 This storage could be successively used as hot storage in winter, and cold storage in summer.

 There is shown at 37 an auxiliary boiler using for example a storable fuel, such as coal. In this case, the tubular pylon 5 advantageously serves as a discharge pipe for the burnt gases.

 38 and 39 are the isolated pipes for the departure and return of hot water, or cold water to the places and devices of use which can be in particular heated floors, cooling ceilings, domestic hot water storage tanks .

Claims (10)

EVE? DIOATIONS 1. Device intended mainly for heating, refrigeration, fluids or for the production of electrical energy, the energy source of which consists partially or entirely of solar radiation, characterized in that it is produced in the form of a vertical cylindrical monobloc assembly forming a transparent glass tower with circular or polyaonal base containing means for receiving, concentrating or converting solar radiation1 these being connected to means of orientation by rotation about a vertical axis in order to be constarn.ent positioned in azimuth facing the sun 2. Device according to claim 1 characterized in that it is established on a pedestal forming technical room vice with one or more conrenant, for thermal uses one or more storage tanks preferably in the basement, an auxiliary boiler , auxiliary devices, associated or not with a heat pump or a distillation unit, and for. uses of electricity supply by photovoltaic channel, an accumulation room and a generator 3. Device according to claim 1 characterized in that the means for receiving and concentrating solar radiation are constituted by a simple curvature mirror of the cylindro-parabolic type with vertical generators, consisting of a thin wall made of sheets of polished metal or aluminized plastic, suspended from a horizontal rigid yard having a profile allowing the concentration of solar radiation to be achieved on a fixed vertical linear focus established along the axis of the device, the maintenance of this cylindro-parabolic shape and the quality of the mirror obtained being provided simultaneously by the pulling of a set of weights ensuring a regular distribution of forces by means of springs and by a series of flexible curved slats of the type used to stiffen the ship's vines, established at regular intervals throughout the height of the mirror 4. Device according to claims 1 and 3 characterized in that a curved mirror of the cylindro-parabolic type with vertical generators consists of polystyrene plates with reflective coating, assembled in a frame of light alloy. 5. Device according to claim 4 characterized in that the flexible plates are shaped by arc bending under the action of wires stretched so as to venerate the desired curvature 6. Device according to claims 1 and 2 characterized in that the light transparent enclosure forming a glass tower is supported by a central mast forming a hollow py lone, recessed, sealed or articulated on a concrete foundation or on the ceiling of a room technical, and stabilized perherically by a series of tensioners supporting rings at ro-ro intervals on which the flexible clastic plates constituting the envelope are screwed 7. Device according to claims 1,9 and 6 according to which the central mast constitutes a hollow pylon equipped externally with means for receiving solar energy and internally forming a chimney in the case of use of an auxiliary boiler 8. Device according to Claims 1, 3 and 4 characterized in that the device for rotating the vertical cylindrical mirror is constituted by an annular turret which can pivot around the axial pylon and actuated by an electric motor acting on a ring gear or by a counter -weight.  9. Device according to any one of claims 1,3,4 and 8 characterized in that the acquisition and the pursuit of the solar energy source in azimuth are carried out by a microprocessor integrating the astronomical data of the place , or by a servo mainly consisting of two pairs of photolectric cells each separated by a diaphragm, each of these couples being established at the two high ends of the mirror wart so that at least a couple of cells are not at the 'shadow 10. Device according to claim 1 according to which the means for converting solar energy are photovoltaic cells into panels or strips, orientable, positioned on either side or in front of the central py lone.