Solar Receiver for Electric Power Conversion System
A solar receiver for conversion of solar radiation to thermal energy includes an enclosure defining a cavity and having an aperture for receiving an influx of concentrated solar radiation. A heat exchanger is received within the cavity for transferring heat out of the solar receiver. The heat exchanger comprises a plurality of heat exchange cells arranged in polygonal array within the cavity. Each heat exchange cell comprises an inlet, an outlet, and a heat exchange matrix interposed within a first volume defined between a first plate and a second plate spaced apart from the first plate. The inlet and outlet are in fluid communication with the first volume and the first plate, second plate, and heat exchange matrix are monolithically bonded as a unit. The first plate receives concentrated solar radiation and the heat exchange media defines a pathway for a fluid flowing from the inlet to the outlet between the first and second plates. The solar receiver further includes an inlet manifold in fluid communication with the inlet of each of the heat exchange cells and an outlet manifold in fluid communication with the outlet of the each of heat exchange cells. In a further aspect, a heat exchanger is provided.
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This application claims the benefit of priority under 35 U.S.C. §119(e) based on U.S. provisional application No. 61/319,042 filed Mar. 30, 2011. The aforementioned provisional application is incorporated herein by reference in its entirety.
BACKGROUNDThe present disclosure relates generally to the field solar energy conversion, and more specifically to the use of solar receivers for heating gases.
DESCRIPTION OF PRIOR ARTIn one aspect, a solar receiver for conversion of solar radiation to thermal energy is provided, which includes an enclosure defining a cavity and having an aperture for receiving an influx of concentrated solar radiation. A heat exchanger is received within the cavity for transferring heat out of the solar receiver. The heat exchanger comprises a plurality of heat exchange cells arranged in polygonal array within the cavity. Each heat exchange cell comprises an inlet, an outlet, and a heat exchange matrix interposed within a first volume defined between a first plate and a second plate spaced apart from the first plate. The inlet and outlet are in fluid communication with the first volume and the first plate, second plate, and heat exchange matrix are monolithically bonded as a unit. The first plate receives concentrated solar radiation and the heat exchange media defines a pathway for a fluid flowing from the inlet to the outlet between the first and second plates. The solar receiver further includes an inlet manifold in fluid communication with the inlet of each of the heat exchange cells and an outlet manifold in fluid communication with the outlet of the each of heat exchange cells. In a further aspect, a heat exchanger is provided.
The present disclosure is directed to a compact heat exchanger intended to function as a cavity solar receiver. While typical solar receivers utilize tubes formed in bundles and involutes, the present design employs a plurality of cellular panels forming a polygonal shell. The densely fined panels are compact heat exchangers designed to absorb highly concentrated solar flux from a parabolic solar concentrator. Its purpose is to enable efficient heating of either one or two separated fluids within the solar cavity.
The fin 2 also conducts heat from the first plate 1 to the second plate 3, thereby providing increased surface area for heat transfer between the fluid 4 and the radiated surface 1.
The three sheets or surfaces 6, 8, and 10, and the two fin matrix elements 11, 12 are bonded to form a composite heat exchanger element 67 with adequate structural integrity to support the structural loads, which are largely pressure-induced. The space behind the third surface 10 is preferably insulated with refractory insulation material 13. The fluids 7 and 9, passing through the first and second fin matrix elements 11 and 12, respectively, are typically at differing pressures. Thus, the individual fin matrix geometries 11, 12 may be optimized to maximize the heat transfer coefficient for the allowable fluid pressure drops.
If the two fluids enter at the same temperature, then the temperature of the second fluid 9 must necessarily lag below the temperature of the first fluid 7, but through careful design practice, this difference may be minimized. In the preferred embodiment, the first fluid 7 would be the higher of the two fluid pressures. The higher-pressure fluid enables a proportionally denser fin or heat exchange matrix 11. A denser fin or matrix is created by closer packed and/or shorter fins, which have the effect of achieving higher heat exchange coefficient between the fluid and the solar irradiated wall 6. An increase in heat transfer coefficient and a denser fin matrix both serve to increase the maximum tolerable solar flux levels. The ability to tolerate highly concentrated solar flux levels allows for a minimization of the solar cavity size and cost.
In a cavity solar absorber, formed into a cylindrical or conical shell comprising multiple heat exchange elements, with is base closest to the aperture, the concentrated solar flux levels are naturally highest near the base. A further characteristic of the preferred solar absorber embodiment is to locate the inlet manifolds 14 and 15 so that the fluid enters the base of the absorber matrix in the vicinity of the highest fluxes; thus forcing the coolest fluid into the region of highest concentrated solar flux.
Composite screen fin, foam metal, or similar matrix allows fluid to flow in three mutually orthogonal directions, x, y, and z. Such a heat exchange matrix allows for converging composite panels with non-parallel sides, forming a trapezoidal cell 76.
The trapezoidal cell or panel 76 may be configured in an array that forms a solar absorbing cavity with a pyramidal interior. With a large number of the trapezoidal heat exchange cells 76, the cavity shape approximates that of a cone, as shown in
A tube or conduit 73 is aligned with a hole in the parting plate 10, with an opening sized to allow the tube 73 to penetrate through the fluid boundary to contact parting plate 8. At the point of contact, the tube 73 is slotted or castellated to enable the first fluid to enter the tube from the space between parting plates 8 and 10. An internal structural rib 64 is shown inside the tube 73 to provide structural enhancements.
As would be understood by persons skilled in the art upon a reading and understanding of this disclosure, several alternatives to the fins 70 and 71 may be employed to perform substantially similar purpose. For example, alternatives such as porous metal media, screen matrices, or machined square pins provide the necessary function of enabling the channeled flow from the fins 11, 12, to travel in direction allowing the fluid to congregate at the transport tube 72. It should also be clear that the aforementioned method of connecting a cell with internal fin structure to a pipe or conduit may be applied to a single cell or a double cell arrangement as shown in
Final assembly is also shown in
The final assembly 38 of elements 30, 32, 33, and 36 is also illustrated in
A family of solar absorbers is illustrated, suitable for cavity-type solar receivers. When the present solar receiver is deployed with a conventional gas turbine cycle (see
A cavity solar receiver containing passages for both first and second stage heating has also been disclosed herein. The underlying principles of series heating arrangements for heating two or more isolated fluid streams are defined and illustrated. The invention has been described with reference to the preferred embodiments. Modifications and alterations may occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims
1. A solar receiver for conversion of solar radiation to thermal energy comprising:
- an enclosure defining a cavity;
- an aperture in said enclosure for receiving an influx of concentrated solar radiation;
- a heat exchanger received within said cavity for transferring heat out of the solar receiver, the heat exchanger comprising a plurality of heat exchange cells arranged in polygonal array within said cavity, each heat exchange cell comprising: a first inlet, a first outlet, and a first heat exchange matrix interposed within a first volume defined between a first plate and a second plate spaced apart from the first plate; said first inlet and said first outlet in fluid communication with said first volume; said first plate, second plate, and first heat exchange matrix monolithically bonded as a unit, said first plate for receiving the concentrated solar radiation; and said first heat exchange media defining a pathway for a first fluid flowing from said first inlet to said first outlet between said first and second plates;
- a first inlet manifold in fluid communication with the first inlet of each of said heat exchange cells; and
- a first outlet manifold in fluid communication with the first outlet of each of said heat exchange cells.
2. The solar received of claim 1, wherein said heat exchange matrix is selected from fins, pins, foam metals, porous metal structures, screen packs, wavy folded sheet, and lanced folded sheet.
3. The solar receiver of claim 1, wherein said heat exchange cells comprise:
- a third plate spaced apart from the second plate and defining a second volume therebetween;
- a second inlet and a second outlet, said second inlet and said second outlet in fluid communication with said second volume;
- a second heat exchange matrix interposed within said second volume;
- said third plate, second plate, and second heat exchange matrix being monolithically bonded;
- said second heat exchange media defining a pathway for a second fluid flowing from said second inlet to said outlet between said second and third plates;
- a second inlet manifold in fluid communication with the second inlet of each of said heat exchange cells; and
- a second outlet manifold in fluid communication with the second outlet of said heat exchange cells.
4. The solar receiver of claim 1, wherein said first plate, second plate, and first heat exchange matrix are bonded together by metallurgical bonding or ceramic sintering.
5. The solar receiver of claim 1, wherein said heat exchange cells comprise:
- a third plate spaced apart from the second plate and defining a second volume therebetween;
- a second inlet and a second outlet, said second inlet and said second outlet in fluid communication with said second volume;
- a second heat exchange matrix interposed within said second volume; and
- said third plate, second plate, and second heat exchange matrix being monolithically bonded.
6. The solar receiver of claim 5, further comprising:
- said first fluid flowing through said first volume and a second fluid flowing through said second volume;
- said first manifold fluidicly connected to the first inlet of each heat exchange cell;
- said second manifold fluidicly connected to the first outlet of each heat exchange manifold;
- a third manifold fluidicly connected to the second inlet of each heat exchange manifold; and
- a fourth manifold fluidicly connected to the second outlet of each heat exchange manifold.
7. A solar receiver of claim 2 where said first fluid has a pressure higher than said second fluid.
8. The solar receiver of claim 1, further comprising:
- said first plate has two long edges and two short edges;
- said two long edges are bent to a generally 90-degree fold in the edge to form a channel;
- said first heat exchange matrix having a width to fit tightly into the channel;
- said second plate is sized to the width of said first heat exchange matrix; and
- said first sheet, first fin element, and second sheet are monolithically bonded.
9. The solar receiver of claim 1 further comprising:
- said first and second sheets having a generally trapezoidal shape;
- said first heat exchange matrix formed of a screen pack, porous foam structure, or an array of pins and cut into a trapezoidal shape which substantially matches the shape of the first and second sheets; and
- said first and second sheets and said first heat exchange matrix monolithically bonded into a substantially trapezoidal heat exchange cell.
10. The solar receiver of claim 8, further comprising:
- said plurality of heat exchange cells forming an array of said substantially trapezoidal cells positioned in the solar cavity to form a polygon shell with a substantially conical shape.
11. A heat exchanger for a solar receiver, comprising:
- a plurality of heat exchange cells arranged in polygonal array, each heat exchange cell comprising: an inlet, an outlet, and a heat exchange matrix interposed within a volume defined between a first plate and a second plate spaced apart from the first plate; said inlet and said outlet in fluid communication with said volume; said first plate, second plate, and heat exchange matrix monolithically bonded as a unit, said first plate for receiving concentrated solar radiation; and said heat exchange media defining a pathway for a fluid flowing from said inlet to said outlet between said first and second plates; and
- an inlet manifold in fluid communication with the inlet of each of said heat exchange cells; and
- an outlet manifold in fluid communication with first outlet of each of said heat exchange cells.
Type: Application
Filed: Mar 30, 2011
Publication Date: Oct 6, 2011
Applicant: SOUTHWEST SOLAR TECHNOLOGIES, INC. (Phoenix, AZ)
Inventors: James B. Kesseli (Greenland, NH), Thomas L. Wolf (Winchester, MA), James S. Nash (North Hampton, NH), Fiona Hughes (Hampton, NH), Shaun D. Sullivan (Northwood, NH), Eric W. Vollnogle (Dover, NH)
Application Number: 13/075,468
International Classification: F24J 2/30 (20060101); F24J 2/24 (20060101);