Trough heat collector element insulator
A concentrating solar collector heat collecting element insulating shield has an elongated hemi-cylindrical body having an internal diameter approximately equivalent to (able to physically engage to) the outer diameter of the concentrating solar power (CSP) heat collecting element, either the evacuated outer tube, the fluid-carrying inner tube, or both. The device may have multiple layers of insulating/reflecting material, sheet metal, polymer, composite, may have flanges, fingers or other attachments to the CSP heat collecting element tube, or may be slightly greater than 180 degrees in arc so as to grip the CSP heat collecting element.
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CROSS-REFERENCE TO RELATED APPLICATIONSN/A
FIELD OF THE INVENTIONThis invention relates generally to concentrating solar power devices, and specifically to heat collector elements of concentrating solar power devices.
STATEMENT REGARDING FEDERALLY FUNDED RESEARCHThis invention was not made under contract with an agency of the US Government, nor by any agency of the US Government.
BACKGROUND OF THE INVENTIONConcentrating solar power (CSP) collectors consist of a long trough of reflective material having a parabolic shape designed to focus the sun's rays upon a long tubular heat collecting element (HCE) running the length of the reflector. The HCE in turn consists of a metal tube through which fluid is pumped. Usually, the HCE is a two tube design having an inner (fluid carrying) tube and an outer tube as well. The outer tube is normally glass with the interior cavity holding the inner tube and being evacuated: the evacuated space between the two tubes serves to insulate the hot inner tube from the ambient environment, at least in terms of conductive heat transfer. When radiant sunlight hits the reflector, it is reflected and concentrated on the HCE, resulting in the HCE becoming hot.
Consideration of the structure of the device shows that sunlight concentrated by the reflector falls primarily on one face of the device. Unconcentrated sunlight directly from the sun is much weaker and is the a negligible source of energy input on the back side of the device.
It would be preferable to take advantage of this asymmetrical energy flux to provide for more effective insulation of the HCE.
SUMMARY OF THE INVENTIONGeneral Summary
A CSP heat collecting element insulating shield has an elongated hemi-cylindrical body having an internal diameter very slightly greater than (or approximately equivalent to, meaning able to physically engage to) the outer diameter of the CSP heat collecting element, either the evacuated outer tube, the fluid-carrying inner tube, or both. The device may have multiple layers of insulating/reflecting material, sheet metal, polymer, may have flanges, fingers or other attachments to the CSP heat collecting element tube, or may be slightly greater than 180 degrees in arc so as to grip the CSP heat collecting element. In diverse embodiments, a positive standoff (for example, 1/32 inch) between the interior diameter of the device and the outer diameter of the HCE tube it is affixed to can be assured by geometry of the fingers or other attachments, or by use of dimples, shims, ridges or other suitable means.
Summary in Reference to Claims
It is therefore a first aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide a concentrating solar power (CSP) heat collecting element device for use on a CSP heat collecting element having an outside diameter and length, the CSP heat collecting element insulating device comprising:
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- a body having a semi-circular cross section and an elongated length, the semi-circular cross section of the body having an inside diameter approximately equal to that of such CSP heat collecting element outside diameter.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device further comprising:
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- an arc of the semi-circular cross section, the arc being greater than 180 degrees, whereby the device may maintain physical engagement with such CSP heat collecting element.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device further comprising:
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- an arc of the semi-circular cross section, the arc being less than 180 degrees;
- at least one upper projection (“finger”) from the body and at least one lower projection (“finger”) from the body, the upper and lower projections (“fingers”) cooperating to maintain physical engagement with such CSP heat collecting element by clipping or gripping when the CSP heat collecting element device is placed on such CSP heat collecting element.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device further comprising:
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- an attachment to such CSP heat collecting element.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device wherein the attachment further comprises one member selected from the group consisting of: a braze weld, a weld, solder, adhesive, bolts, tabs, detents, hooks, studs, rivets and combinations thereof.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device wherein the elongated length is approximately the same as such CSP heat collecting element length.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device wherein the body is sheet metal.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device wherein the body is high temperature polymer or composite.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device used on a CSP heat collecting element having an inner fluid-carrying tube and an outer evacuated tube, respectively having an inner fluid-carrying tube outer diameter and an outer evacuated tube outer diameter, wherein:
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- the semi-circular cross section inner diameter is approximately equal to the inner fluid-carrying tube outer diameter.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device used on a CSP heat collecting element having an inner fluid-carrying tube and an outer evacuated tube, respectively having an inner fluid-carrying tube outer diameter and an outer evacuated tube outer diameter, wherein:
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- the semi-circular cross section inner diameter is approximately equal to the outer evacuated tube diameter.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device used on a CSP heat collecting element having an inner fluid-carrying tube and an outer evacuated tube, respectively having an inner fluid-carrying tube outer diameter and an outer evacuated tube outer diameter, further comprising:
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- a second body having a second semi-circular cross section and a second elongated length, the semi-circular cross section of the body having a diameter approximately equal to that of such CSP heat collecting element;
- the first body semi-circular cross section inner diameter approximately equal to such CSP heat collecting element outer evacuated tube outer diameter; and
- the second body semi-circular cross section inner diameter approximately equal to such CSP heat collecting element inner fluid-carrying tube outer diameter.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device used on a CSP heat collecting element having an inner fluid-carrying tube and an outer evacuated tube, respectively having an inner fluid-carrying tube outer diameter and an outer evacuated tube outer diameter, further comprising:
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- at least one standoff device dimensioned and configured to maintain a standoff between the body inside diameter and the CSP heat collecting element outside diameter.
It is therefore another aspect, advantage, objective and embodiment of the invention to provide a CSP heat collecting element device used on a CSP heat collecting element having an inner fluid-carrying tube and an outer evacuated tube, respectively having an inner fluid-carrying tube outer diameter and an outer evacuated tube outer diameter; wherein the standoff device further comprises:
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- at least one dimple.
- Concentrating solar power collector (CSP) 100
- Reflector trough 102
- Heat collecting element (HCE) 104
- Heat collecting element (HCE) 200
- Evacuated outer tube 202
- Evacuated chamber 204
- Fluid-carrying inner tube 206
- Fluid conduit 208
- Evacuated outer tube 302
- Shield device body 310
- Fluid-carrying inner tube 406
- Shield device 410
- Shield device 510
- Attachment 512
- Shield device body 610
- Shield device body 710
- First type of finger 714
- Second type of finger 716
- Shield device body 800
- First layer 820
- Second layer 822
- Third layer 824
- Evacuated outer tube 902
- Shield device body 910
- Dimple 990
For purposes of the present application, “approximately equal” or “slightly greater than” means a diameter or length able to make physical engagement with another diameter or length by means of being the same within a close tolerance, usually meaning a diameter at least one or two mils greater than the diameter of the HCE tube to be gripped or a length at least one or two mils less than the length of the HCE tube to be gripped. However, if the materials are flexible, even one or two mils difference may not be necessary, while if the material is not flexible or the configuration is not conducive to a tight grip, a diameter more than one or two mils greater may fit the applicant's chosen definition. This is important as the retrofit embodiments of the invention allows easy installation to the installed base of CSP systems, while the original equipment embodiments of the invention may be more easily manufactured. In addition, the slight gap shown in the diagrams in between the inner surface of the insulating shield and the outer surface of the HCE tube to which it is attached assures the insulating ability of the device. In diverse embodiments, a positive standoff (for example, 1/32 inch) between the interior diameter of the device and the outer diameter of the HCE tube it is affixed to can be assured by geometry of the fingers or other attachments, or by use of dimples, shims, ridges or other suitable means.
In use, the shield will act to insulate the side of the HCE which is facing away from the reflector trough, reducing heat losses by radiation, convection and/or conduction.
Note that in CSP systems which may have only a single tube, this configuration is the default configuration, though such CSP systems are at best rare, due to the fact that the evacuation is usually necessary for economical operation.
In general these configurations are held onto the tube simply be a physical engagement thereto, which may be clamping or clasping, for example. In a simple preferred embodiment, the device is held on by virtual of having an arc of a circle measuring slightly more than 180 degrees. The degree of arc in excess of 180 will depend on the ductility and nature of the materials used in the device and HCE, for example, with sheet metal or softer polymers an arc of 190 or 210 degrees is perfectly possible, as the material will allow itself to pass over the HCE easily. With harder polymers, metals or the like, this can be reduced, as the material will have less give and will thus hold itself on with a smaller angle, and will require a smaller angle in order to fit on. Angles of approximately 181 degrees can be envisioned.
Such embodiments may be used in “deep trough” designs in which the CSP reflector trough is deeper and radiates to a wider arc of the HCE. On the other hand “shallow trough” designs, in which the reflector trough is less than 180 degrees, would likely be more acceptable for use with the embodiments having a greater than 180 degree arc.
In the presently preferred embodiment and best mode presently contemplated for carrying out the invention, the device may be standardized to standard HCE sizes and provided in lengths shorter than the HCE, with multiple devices used to cover the length of the HCE.
The disclosure is provided to render practicable the invention by those skilled in the art without undue experimentation, including the best mode presently contemplated and the presently preferred embodiment. Nothing in this disclosure is to be taken to limit the scope of the invention, which is susceptible to numerous alterations, equivalents and substitutions without departing from the scope and spirit of the invention. The scope of the invention is to be understood from the appended claims.
Claims
1. A CSP heat collecting element insulating device for use on a CSP heat collecting element having an outside diameter and length, the CSP heat collecting element insulating device comprising:
- a body having a semi-circular cross section and an elongated length, the semi-circular cross section of the body having an inside diameter approximately equal to that of such CSP heat collecting element outside diameter.
2. The CSP heat collecting element insulating device of claim 1, further comprising:
- an arc of the semi-circular cross section, the arc being greater than 180 degrees, whereby the device may maintain physical engagement with such CSP heat collecting element.
3. The CSP heat collecting element insulating device of claim 1, further comprising:
- an arc of the semi-circular cross section, the arc being less than 180 degrees;
- at least one upper projection from the body and at least one lower projection from the body, the upper and lower projections cooperating to maintain physical engagement with such CSP heat collecting element when the CSP heat collecting element device is placed on such CSP heat collecting element.
4. The CSP heat collecting element insulating device of claim 1, further comprising:
- an attachment to such CSP heat collecting element.
5. The CSP heat collecting element insulating device of claim 4, wherein the attachment further comprises one member selected from the group consisting of: a braze weld, a weld, solder, adhesive, bolts, tabs, detents, hooks, studs, rivets and combinations thereof.
6. The CSP heat collecting element insulating device of claim 1, wherein the elongated length is approximately the same as such CSP heat collecting element length.
7. The CSP heat collecting element insulating device of claim 1, wherein the body is sheet metal.
8. The CSP heat collecting element insulating device of claim 1, wherein the body is high temperature polymer or composite.
9. The CSP heat collecting element insulating device of claim 1 used on a CSP heat collecting element having an inner fluid-carrying tube and an outer evacuated tube, respectively having an inner fluid-carrying tube outer diameter and an outer evacuated tube outer diameter, wherein:
- the semi-circular cross section inner diameter is approximately equal to the inner fluid-carrying tube outer diameter.
10. The CSP heat collecting element insulating device of claim 1 used on a CSP heat collecting element having an inner fluid-carrying tube and an outer evacuated tube, respectively having an inner fluid-carrying tube outer diameter and an outer evacuated tube outer diameter, wherein:
- the semi-circular cross section inner diameter is approximately equal to the outer evacuated tube diameter.
11. The CSP heat collecting element insulating device of claim 1 used on a CSP heat collecting element having an inner fluid-carrying tube and an outer evacuated tube, respectively having an inner fluid-carrying tube outer diameter and an outer evacuated tube outer diameter, further comprising:
- a second body having a second semi-circular cross section and a second elongated length, the semi-circular cross section of the body having a diameter approximately equal to that of such CSP heat collecting element;
- the first body semi-circular cross section inner diameter approximately equal to such CSP heat collecting element outer evacuated tube outer diameter; and
- the second body semi-circular cross section inner diameter approximately equal to such CSP heat collecting element inner fluid-carrying tube outer diameter.
12. The CSP heat collecting element insulating device of claim 1, further comprising:
- at least one standoff device dimensioned and configured to maintain a standoff between the body inside diameter and the CSP heat collecting element outside diameter.
13. The CSP heat collecting element insulating device of claim 12, wherein the standoff device further comprises:
- at least one dimple.
Type: Application
Filed: Feb 12, 2009
Publication Date: Aug 12, 2010
Inventor: William Joseph Blomberg (Parker, CO)
Application Number: 12/378,369
International Classification: F24J 2/00 (20060101);