IL62528A

IL62528A - Solar radiation heating apparatus

Info

Publication number: IL62528A
Application number: IL6252881A
Authority: IL
Original assignee: Klier Shimon
Priority date: 1981-03-30
Filing date: 1981-03-30
Publication date: 1994-05-30
Also published as: ZA822018B; JPS57174659A; IL62528A0

Description

SOLAR RADIATION HEATING APPARATUS SHIMON KLIER C: 00905 SHIMON KLIER SOLAR RADIATION INSULATION APPARATUS / FIELD OF THE INVENTION The present Invention relates to insulation generally nd more particularly to ^nsulatloh a^paratUs^and structures which re) substantially light transmisslve.

BACKGROUND OF THE INVENTION The problem of insulation is a concern of Increasing Importance throughout the world in view of the current energy crisis. Of particular Interest is the problem of providing thermal insulation which does not Interfere with the passage of radiation* such as light and heat 1n one direction.

One practical example,of a system which requires Insulation for enhanced efficiency Is the solar pond which is described in: H. Weinberger. The physics of the solar pond. Solar Energy .

Volume 8, page 45 (1964) In order to lower the significant heat losses to the atmosphere at the surface of the pond, 1t Js considered desirable to provide some sort of stable air layer between the pond surface and the atmosphere. The construction of such an air gap over a relatively large area does not appear to be feasible due to the difficulty of providing and maintaining In place over the pond a cover which Is transmisslve to solar radiation.

SUMMARY OF THE INVENTION The present invention seeks to provide thermal conduction Insulation which Is radiation transmisslve.

There Is thus provided in accordance with an embodiment of the present Invention thermal Insulation which Is radiation transmisslve and comprising a layer of bubbles In a free state. The term " free state" is employed to distinguish the layer of bubbles from a solid material formed of a foamed material » such as foam polystyrene. In accordance with the present Invention* the layer of bubbles is a dynamic system with new bubbles being formed and existing bubbles reducing to liquid continually. The layer of bubbles may comprise a multiplicity of layers of bubbles.

Further in accordance with an embodiment of the present invention there is provided a radiation' transmissive securing web member, such as a net or screen over the bubble layer so as to prevent the bubbles from being blown away by wind or other forces.

Additionally in accordance with an embodiment of the present invention, the bubble layer is formed over a liquid surface.

Apparatus for providing a bubble layer over a liquid surface is provided and comprises means for providing a flow of gas to the liquid so as to produce bubbles therein. The providing apparatus may comprise a network of apertured conduits disposed in the liquid below the surface thereof and a gas compressor operative to provide compressed gas to the conduits.

According to a preferred embodiment of the present invention, a selectable insulation layer may be provided by controlling the operation of the compressor for producing a layer of bubbles of ^ selectable thickness, density and bubble size.

The bubbles may be produced in any suitable manner as by adding a surfactant which may have either a higher or lower surface tension than that of the liquid.

A particularly interesting example of the use of a selectable insulation layer according to the present invention is for covering solar ponds for reducing the conduction heat losses thereof to the atmosphere without appreciably affecting their absorption characteristics. In such an embodiment, a solar pond can be made of ordinary l quid which preferably contains particulate matter so as to absorb radiation. The liquid need not contain a high concentration of salts as in conventional solar-ponds, since convection currents in the pond itself constitute a difficulty. Normally the hottest part of the pond will be at the top thereof and as a result lowered heat losses to the atmosphere will be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood and appreciated from the following detailed description taken in conjunction with the drawing in which: Fig.1 is a sectional illustration of apparatus for producing an insulating layer constructed and operative in Reference Is now made to Fig. 1 which Illustrates apparatus for producing a bubble layer for Insulation purposes* In the Illustrated embodiment a bubble layer Is provided over the surface of a body of liquid such as water. , The bubbles are provided by an air compressor 10 which communicates via a conduit 12 with a plurality of apertured air outlet tubes 14 which are disposed within a body of liquid 16 and below the'llquid surface 18. A bubble laye 20 Is thus produced and 1s retained against being blown away by a securing web element 22, such as a screen or web of fabric.

..' It Is a particular feature of the present Invention t that the bubble layer 1s substantially transmlsslve to solar radiation, thus permitting heating of the liquid body lying therebelow. At the same time the bubble layer acts as an excellent thermal insulator and prevents significant heat losses from the body of water to the outside atmosphere by conduction.

It is also a particular feature of the present Invention that a solar pond can be constructed using non-saline water by covering the body of water with a bubble layer as described above. The heat of the pond is retained due to the Insulating layer* Additional benefits of Insulation are. ealized due to the fact that In a solar pond of this typet the hottest location will be at the top and thus the surrounding water provides Insulation from the adjacent ground surfaces.

According to a preferred embodiment of the present invention, the height of the bubble layer can be varied at will or in accordance with a predetermined program by suitable control of the volume of gas supplied, as by a valve 13. Thus different levels of Insulation can be provided during day and night periods and during periods of the presence or absence of sunshine. Such a feature 1s desirable since the transmlsslvity of the bubble layer to solar radiation decreases as a function of increasing thickness. A relatively thin bubble layer Is therefore required during a sunny day and a relatively thick bubble layer Is required during a cold night.

The securing web 22 may be constructed to be raisable and lowerable or alternatively stretchable In order to accomodate the different heights of the bubble layer.

It 1s a particular feature of the present Invention that the Insulation layer is Insulatlve with respect to thermal conduction but transmissive of solar radiation.

- - From the foregoing it may be appreciated that the insulation provided by the present invention is a dynamic system which can readi ly be adjusted to sui t changing requirements .

Il is appreciated that the usefulness of the bubble layer insulating system of the present invention is not l imited to solar ponds , nor to insulating the surfaces of l iquids . For example, the system may be employed to heat a body of fuel which requi res preheating to a relatively low temperature before being suppl ied to a boi ler. Furthermore, the bubbles may be generated over a sol id surface ., shown and described herein. Rather the scope of the present i nvention is defined only by the claims which fol low: 62528/5

Claims

1. Apparatus for heating an object by solar radiation comp sing: a layer of bubbles which is transmissive to radiation and insulative with respect to thermal conduction disposed in solar radiation receiving relationship over said object .

2. Apparatus according to claim 1 and also comprising a securing web placed over said layer of bubbles.

3. Apparatus according to claim 1 or claim 2 wherein said object comprises a body of liquid.

4. Apparatus according to any preceding claim wherein said bubbles are in a free state.

5. A solar pond comprising: a body of water ; and a layer of bubbles which is transmissive to radiation and insulative with respect to thermal conduction disposed in solar radiation receiving relationship over said body of water.

6. A solar pond according to claim 5 wherein said layer of bubbles is retained over said body of water by a securing web.

7. · A solar pond according to claim 5 or claim 6 wherein said body of water contains particulate matter which absorbs solar* radiation . - 6 - 62528/5

8. A solar pond according to any of claims 5 to 7 wherein said bubbles are in a free state.

9. A solar pond according to any of claims 5 to 7 and further comprising apparatus for providing a layer of bubbles as defined in claim 1 which comprises: a source of pressurized air; means for providing pressurized air to a liquid thereby forming bubbles therein; and a securing web disposed above the layer of bubbles thus produced .

10. A solar pond according to claim 9 wherein said source of pressurized air is selectably operable for providing a bubble layer of selectable height.

11. A solar pond according to claim 10 and also comprising control means for operating said source of pressurized air for providing enhanced insulation in response to indicated environmental conditions.

12. Apparatus substantially as described hereinbefore. 13· Apparatus substantially as described hereinbefore with reference to any of the drawings. For the Applicant, Sanford T. Colb Advocate and Patent Attorney