IL82152A - Solar reservoir regulation - Google Patents

Description

SOLAR RESERVOIR REGtJLATION BACKGROUND OF THE INVENTION This invention relates generally to solar reservoir, pond or pool regulation and more particularly to a method and apparatus for controlling and/or enhancing the solar energy accumulation and its transfer to the reservoir medium and controlling and/or retarding heat loss or transfer from the medium to the environment.

Solar reservoir management has been the subject of much research and experimentation in order to improve the efficiency thereof in order to provide improved energy utilization to lessen the dependency of countries on fossil fuels.

Covered reservoir applications are limited by economic and technical shortcomings. Suspended coverings require expensive covering materials and a support system therefor. Additionally, the covered reservoir system suffers from the requirement for treatment of the cover against drop condensation, which, as opposed to film condensation, increases tenfold the heat transfer to the surroundings. Changing levels of the reservoir medium and, therefore, the air volume between the medium and the covering affect the heat transfer patterns within the reservoir. Because of the foregoing and other considerations, the art has developed towards the utilization of floating bodies.

One floating body system involves the provision of a foam on the surface of the solar reservoir, which requires means to hold the foam in place and foam generating and placement apparatus. A system of - 3 - 82152/3 and has the same deficiencies as the previously mentioned foam system.

German Patent 2,805,723 describes a device for the extraction of oxygen by means of solar energy. The means therefor include floating bodies in the form of concave mirrors.

German Patent 2,650,208 teaches a device for warming water constituted by a hollow brick shaped body made of plastic material and having a surface composed of a multiplicity of convex half-lenses, which enlarge the total surface area in such a way that the incident sun rays contribute to the heating of the water.

Bead blankets and rafts of various materials and shapes such as those disclosed in Israel Patent 63678 and in U.S. Patent 3,072,920 have been preferred in order to provide lower cost devices to improve the operation of solar reservoirs, however, further increase in efficiency and reduction of costs are still required in order to render this system viable.

SUMMARY OF THE INVENTION This invention involves the provision of a new, more efficient system for the control and operation of solar reservoirs, ponds or pools with applications to heat collectors, desalination, brine concentration, salt production, fresh water production, industrial algology, etc.

Accordingly, it is an object of this invention to provide a floating body, solar pool, pond or reservoir control system that collects received solar energy to increase the temperature of the liquid medium of the solar reservoir, and at the same time acts as an insulator during periods when solar energy is absent or reduced.

It is another object of this invention to provide evaporation regulation for shallow solar reservoirs.

It is still another object of this invention to provide apparatus for solar reservoir regulation that is easy and economical to produce of standard, currently available materials that lend themselves to mass production manufacturing techniques. - 4 - 82152/2 A still further object of the invention involves the production of a module for solar regulation of shallow reservoirs wherein the module is relatively unaffected by dust.

In accordance with the above objects, the present invention provides a method for controlling the energy accumulation and dissipation of a solar reservoir containing a liquid fluid medium having the upper surface in contact with a gaseous fluid medium comprising the step of providing a plurality of floatable, hollow modules, wherein each module comprises an upper convexed portion of material having a high transparency for receiving and transmitting solar energy radiation therethrough, a lower portion affixed to said upper portion and having a high heat conductivity and an energy absorbent coating on its inner surface for receiving energy radiation transmitted through said upper portion and for conducting the absorbed energy to the liquid of said solar reservoir, means for interconnecting one module with at least one further at least similar module, determining the number of modules necessary for controlling the energy accumulation and dissipation of said reservoir, linking the necesssary number of modules to each other, and floating the justly assembled modules between said mediums.

The present invention also provides a floatable, hollow module for use in controlling energy accumulation and dissipation to and from a liquid containing solar reservoir, said module comprising an upper convex portion of material having a high transparency for receiving and transmitting solar energy radiation therethrough, and a lower portion affixed to said upper portion and having a high heat conductivity and an energy absorbent coating on its inner surface for 82152/2 - 5 - for conducting the absorbed energy to the liquid of said solar reservoir.

The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood.

With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Fig. 1 is a plan view of a portion of a floating body, conforming to the principles of this invention; Fig. 2 is a plan view of an individual floating module; and Fig. 3 is a cross section along line 11-11 of Figure 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The structure of this invention takees into acount the factors affecting enthalpy changing of a liquid medium under solar radiation where the liquid medium is in contact with a gaseous medium such as a) the exposed surface of contact between the two mediums, b) the saturated vapor pressure at the liquid surface, c) the absorption, refraction and reflection coefficients of the mediums, d) the state of motion of the two fluid mediums, and e) the heat transfer coefficients and temperature of the fluids. For the purpose of explanation only, the individual floating bodies will be referred to in the specification as modules, while the assembly will retain the appellation of a floating body. Thus with reference to Figures 1 and 2 there is shown a portion of a floating body 10 comprising a series of interlinked modules 12. Top surface 14 of the module 12 presents a circular face toward a gaseous medium, and as can be seen by the cross sectional view in Figure 3, is an oblate spheroid. This shape allows for desirable optical properties and has a small, dust influence on the transparency of surface 14.

Surface 14 is of plastic material having high, constant in time, transparency with a wall thickness providing a small absorption coefficient and departs from the spheroid shape to form a flange 16. This flange feature enables the use of parallelogram shaped modules 12 while retaining the oblate spheroid shape with its attendant advantages. The plastic surface 14, in addition to its normal focusing, may have a focusing lens incorporated therein for directing the solar energy within the module 12. The oblate spheroid provides for a large surface area between the liquid and the surrounding gaseous fluid. Of course, different geometrical shapes could regulate the energy receiving coverage of the reservoir surface area which in turn regulates the rate of heat absorption.

The bottom portion or surface 18 of the module 12 also conforms to an oblate spheroid shape, which should be symmetrical with surface 14 or differ, as illustrated. The top and bottom surfaces 14 and 18 are sealed at the flange edges to enclose the gas therebetween. Surface 18 is in contact with the liquid fluid medium and serves to transfer the heat received from the sun to the liquid fluid with which it has contact. To improve the efficiency, the inner surface of bottom surface 18 is provided with a heat absorbing, black coating at 20, while the material of the bottom portion provides for efficient heat transfer. At the same time, when sun rays are not received upon the module, the latter, because of the air or other gas trapped between the top and bottom portions and the poor heat transmitting properties of the plastic of upper surface 14, serves as an insulator. To further enhance the insulating and heat transmission properties of the bottom surface 18, a reflective metallized coating could be applied to the external surface thereof.

By shaping the modules 12 with edges that abut adjacent modules, e.g., rectangular modules, total covering of the reservoir liquid surface could be effected with minimization of dissipated energy, while the accumulated energy is considerably increased. As shown in Figure 1, securing elements 22 engage holes 24 formed in the modules 12 in order to link and secure adjacently disposed modules one to the other. The securing elements may be of any type known per-se including being adjustable in length.

The method of this invention involves the covering of the surface of the reservoir with floating bodies between the two fluids and having particular characteristics to change the relation between the heat collected and dissipated by the reservoir.

When the regulation of evaporation is important, for example, for increasing brine concentration and for the production of salts, the percentage coverage of the reservoir surface by the floating modules could be regulated also by coupling the individual modules by means of longer securing elements 22 or adjusting the length thereof to allow for spacing between the modules. When two vessels with the same volume and geometric shape and with the same brine solution were tested, one vessel with 30% coverage with floating modules and the other with none, the covered vessel had a daily evaporation rate 0.6% greater than the uncovered vessel.

Thus, the utilization of floating modules or bodies increases the temperature of a solar, liquid containing reservoir, by providing a structure that uses the principle of a blackened body, and may also control evaporation by varying the coverage of the reservoir by regulating the spacing interconnection of the modules.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (8)

10 - 82152/2 WHAT IS CLAIMED IS:

1. A method for controlling the energy accumulation and dissipation of a solar reservoir containing a liquid fluid medium having the upper surface in contact with a gaseous fluid medium comprising the step of: providing a plurality of floatable, hollow modules, wherein each module comprises an upper convexed portion of material having a high transparency for receiving and transmitting solar energy radiation therethrough, a lower portion affixed to said upper portion and having a high heat conductivity and an energy absorbent coating on its inner surface for receiving energy radiation transmitted through said upper portion and for conducting the absorbed energy to the liquid of said solar reservoir, and means for interconnecting one module with at least one further at least similar module; determining the number of modules necessary for controlling the energy accumulation and dissipation of said reservoir; linking the necesssary number of modules to each other, and floating the justly assembled modules between said mediums.

2. A floatable, hollow module for use in controlling energy accumulation and dissipation to and from a liquid containing solar reservoir, said module comprising: an upper convex portion of material having a high transparency for receiving and transmitting solar energy radiation therethrough, and a lower portion affixed to said upper portion and having a high heat conductivity and an energy absorbent coating on its inner - π - 82152/2 surface for receiving energy radiation transmitted through said upper portion and for conducting the absorbed energy to the liquid of said solar reservoir.

3. The module as defined in claim 2 wherein said upper and lower surfaces are oblate spheroid in shape.

4. The module as defined in claim 2 wherein the outer perimeter of said module is substantially rectangular in shape.

5. The plurality of floatable, hollow modules as defined in Claim 2, further comprising connecting means for engaging the flanges of adjacent modules.

6. The plurality of floatable, hollow modules as defined in Claim 2, wherein each of said modules is interconnected with at least one other module to form a floating body.

7. A method for controlling the energy accumulation and dissipation of a solar reservoir, substantially as hereinbefore described and with reference to the accompanying drawings.

8. A floatable hollow module for use in controlling energy accumulation and dissipation to and from a liquid containing solar reservoir substantially as hereinbefore described and with reference to the accompanying drawings. FOR THE APPLICANT WOLFF, BREGMAN AND GOLLER