Patent US4121564A successfully refreshed from Google Patents.
US4121564A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solar energy receiver
Assignee: Lockheed Martin Corp
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Filing: 1977-02-04
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Granted: 1978-10-24
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Expires: 1997-02-04
Abstract
Abstract An improved long-life design for solar energy receivers provides for greatly reduced thermally induced stress and permits the utilization of less expensive heat exchanger materials while maintaining receiver efficiencies in excess of 85% without undue expenditure of energy to circulate the working fluid. In one embodiment, the flow index for the receiver is first set as close as practical to a value such that the Graetz number yields the optimal heat transfer coefficient per unit of pumping energy, in this case, 6. The convective index for the receiver is then set as closely as practical to two times the flow index so as to obtain optimal efficiency per unit mass of material.
Inventors
- 👤 Jacob Schwartz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:57
CPC Classifications
F; F03; F03G; F03G6/00; F03G6/06; F03G6/064; F24; F24S; F24S10/00; F24S10/80; F24S20/00; F24S20/20; F24S23/00; F24S23/70; F24S2023/87; Y; Y02; Y02E; Y02E10/00; Y02E10/40; Y02E10/44; Y02E10/46
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
96 words
A method of providing an optimally designed long life solar energy receiver, comprising: providing a receiver having a face adapted to be exposed to focused solar radiation, said face having an aperture therethrough, a heat exchanger positioned within the receiver so as to be illuminated by focused solar radiation passing through said aperture, said heat exchanger having channels, and means for providing a working fluid to said channels at a predetermined rate; and setting the convective and flow indices for the receiver so as to minimize the face temperature of the heat exchanger in the receiver.
Claim 2
Independent Claim
96 words
A method of providing an optimally designed long life solar energy receiver, comprising: providing a receiver having a face adapted to be exposed to focused solar radiation, said face having an aperture therethrough, a heat exchanger positioned within the receiver so as to be illuminated by focused solar radiation passing through said aperture, said heat exchanger having channels, and means for providing a working fluid to said channels at a predetermined rate; and setting the convective and flow indices for the receiver so as to minimize the face temperature of the heat exchanger in the receiver.
Claim 3
Dependent Claim
44 words
The method of claim 1 wherein the flow index is dependent upon the Graetz number and wherein the Graetz number to which the receiver is set is that which minimizes pumping energy while at the same time maximizing energy transfers to the working fluid.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein the flow index is dependant upon the Graetz number and wherein the Graetz number is 6.
Claim 5
Dependent Claim
15 words
The method of claim 1 wherein the convective index is approximately twice the flow index.
Claim 6
Independent Claim
87 words
A method of prolonging the life of a solar energy receiver, comprising: providing receiver having a face adapted to be exposed to focused solar radiation; said face having an aperture therethrough, a heat exchanger positioned so as to be exposed to focused solar radiation passing through said aperture, said heat exchanger having channels, and means for providing a working fluid to said channels at a predetermined rate; and setting the convective and flow indices of the receiver such that temperature differences along the heat exchanger are minimized.
Claim 7
Independent Claim
87 words
A method of prolonging the life of a solar energy receiver, comprising: providing receiver having a face adapted to be exposed to focused solar radiation; said face having an aperture therethrough, a heat exchanger positioned so as to be exposed to focused solar radiation passing through said aperture, said heat exchanger having channels, and means for providing a working fluid to said channels at a predetermined rate; and setting the convective and flow indices of the receiver such that temperature differences along the heat exchanger are minimized.
Claim 8
Dependent Claim
44 words
The method of claim 5 wherein the flow index is depending upon the Graetz number and wherein the Graetz number to which the receiver is set is that which minimizes pumping energy while at the same time maximizing energy transfer to the working fluid.
Claim 9
Dependent Claim
22 words
The method of claim 5 wherein the flow index is dependent upon the Graetz number and wherein the Graetz number is 6.
Claim 10
Dependent Claim
15 words
The method of claim 5 wherein the convective index is approximately twice the flow index.
Claim 11
Independent Claim
79 words
A method of prolonging the life of a solar energy receiver utilizing a working fluid and which has a heat exchanger face illuminated by focused solar radiation by setting the flow and convective indices of said receiver such that the face temperature of the heat exchanger is within a predetermined small percent of the exit fluid temperature, said heat exchanger having channels and said receiver having means for providing a working fluid to said channels at a predetermined rate.
Claim 12
Independent Claim
79 words
A method of prolonging the life of a solar energy receiver utilizing a working fluid and which has a heat exchanger face illuminated by focused solar radiation by setting the flow and convective indices of said receiver such that the face temperature of the heat exchanger is within a predetermined small percent of the exit fluid temperature, said heat exchanger having channels and said receiver having means for providing a working fluid to said channels at a predetermined rate.
Claim 13
Dependent Claim
44 words
The method of claim 9 wherein the low index is dependent upon the Graetz number and wherein the Graetz number to which the receiver is set is that which minimizes pumping energy while at the same time maximizing energy transfer to the working fluid.
Claim 14
Dependent Claim
22 words
The method of claim 9 wherein the flow index is dependent upon the Graetz number and wherein the Graetz number is 6.
Claim 15
Dependent Claim
15 words
The method of claim 9 wherein the convective index is approximately twice the flow index.
Claim 16
Independent Claim
89 words
A method of providing an optimally designed long life solar receiver, comprising: providing a receiver having a housing with an aperture adapted to be exposed to focused solar radiation, a heat exchanger positioned so as to be exposed to focused solar radiation passing through said aperture, said heat exchanger having channels, and means for providing a working fluid to said channels at a predetermined rate; and setting the cavity ratio, convective index, and flow index of the receiver, such that the heat exchanger runs at a substantially uniform temperature.
Claim 17
Independent Claim
89 words
A method of providing an optimally designed long life solar receiver, comprising: providing a receiver having a housing with an aperture adapted to be exposed to focused solar radiation, a heat exchanger positioned so as to be exposed to focused solar radiation passing through said aperture, said heat exchanger having channels, and means for providing a working fluid to said channels at a predetermined rate; and setting the cavity ratio, convective index, and flow index of the receiver, such that the heat exchanger runs at a substantially uniform temperature.
Claim 18
Dependent Claim
44 words
The method of claim 13 wherein the flow index is dependent upon the Graetz number and wherein the Graetz number to which the receiver is set is that which minimizes pumping energy while at the same time maximizing energy transfer to the working fluid.
Claim 19
Dependent Claim
22 words
The method of claim 13 wherein the flow index is dependent upon the Graetz number and wherein the Graetz number is 6.
Claim 20
Dependent Claim
15 words
The method of claim 13 wherein the convective index is approximately twice the flow index.
Claim 21
Dependent Claim
227 words
A solar energy receiver for use with focused solar energy and a working fluid wherein the focusing system has an f/number, N F , comprising: a housing adapted to be located at the focus of said focusing system, said housing having an open end adapted to face said focusing means such that focused sunlight passes through said open end, said open end defining an aperture of a size A Ap , a heat exchanger within said housing having a number of channels each of length L and a diameter D, said channels having a total surface area in contact with the working fluid, A s , said channels being opened towards said aperture and having a face area A h , and, means for directing fluid flow through said channels such that when solar energy is focused onto said heat exchanger said fluid is heated, the convective index of said receiver, U eff A s /A Ap , being equal to or greater than the flow index of said receiver, m C p /A Ap , the optical index of said receiver, L/DN F , being greater than 6, and the Graetz number being equal to or less than 6, where U eff is the effective coefficient of heat transfer, m is the mass flow rate, and C p is the heat capacity of the working fluid.
Claim 22
Dependent Claim
227 words
A solar energy receiver for use with focused solar energy and a working fluid wherein the focusing system has an f/number, N F , comprising: a housing adapted to be located at the focus of said focusing system, said housing having an open end adapted to face said focusing means such that focused sunlight passes through said open end, said open end defining an aperture of a size A Ap , a heat exchanger within said housing having a number of channels each of length L and a diameter D, said channels having a total surface area in contact with the working fluid, A s , said channels being opened towards said aperture and having a face area A h , and, means for directing fluid flow through said channels such that when solar energy is focused onto said heat exchanger said fluid is heated, the convective index of said receiver, U eff A s /A Ap , being equal to or greater than the flow index of said receiver, m C p /A Ap , the optical index of said receiver, L/DN F , being greater than 6, and the Graetz number being equal to or less than 6, where U eff is the effective coefficient of heat transfer, m is the mass flow rate, and C p is the heat capacity of the working fluid.
Claim 23
Dependent Claim
51 words
The receiver of claim 17 wherein the flow index of the receiver is equal to or less than 6kl/D 2 r c , where r c = A h /A Ap , A h is the heat exchanger face area and where k is the thermal conductivity of the working fluid.
Claim 24
Dependent Claim
109 words
A solar energy receiver for use with focused solar energy comprising: a housing having an open end, said housing adapted to be oriented such that focused sunlight passes through said open end, a heat exchanger within said housing having a number of channels, said channels opened towards said aperture, and, means for directing fluid flow through said channels such that when solar energy is focused onto said heat exchanger said fluid is heated, the convective index of said receiver being approximately twice the flow index of said receiver, the optical index of said receiver being greater than 6, and the Graetz number being equal to or less than 6.
Claim 25
Dependent Claim
109 words
A solar energy receiver for use with focused solar energy comprising: a housing having an open end, said housing adapted to be oriented such that focused sunlight passes through said open end, a heat exchanger within said housing having a number of channels, said channels opened towards said aperture, and, means for directing fluid flow through said channels such that when solar energy is focused onto said heat exchanger said fluid is heated, the convective index of said receiver being approximately twice the flow index of said receiver, the optical index of said receiver being greater than 6, and the Graetz number being equal to or less than 6.
Claim 26
Dependent Claim
129 words
A solar energy receiver for use with focused solar energy comprising: a housing having an open end, said housing adapted to be oriented such that focused sunlight passes through said open end, a heat exchanger within said housing having a number of channels, said channels opened towards said aperture, and, means for directing fluid flow through said channels such that when solar energy is focused onto said heat exchanger said fluid is heated, the convective index of said receiver being approximately twice the flow index for said receiver, and the Graetz number being equal to or less than 6, whereby the heat exchanger temperature profile is relatively flat and substantially horizontal to reduce thermal shock and increase the lifetime of said receiver without significant increases in expended pumping energy.
Claim 27
Dependent Claim
129 words
A solar energy receiver for use with focused solar energy comprising: a housing having an open end, said housing adapted to be oriented such that focused sunlight passes through said open end, a heat exchanger within said housing having a number of channels, said channels opened towards said aperture, and, means for directing fluid flow through said channels such that when solar energy is focused onto said heat exchanger said fluid is heated, the convective index of said receiver being approximately twice the flow index for said receiver, and the Graetz number being equal to or less than 6, whereby the heat exchanger temperature profile is relatively flat and substantially horizontal to reduce thermal shock and increase the lifetime of said receiver without significant increases in expended pumping energy.
Claim 28
Dependent Claim
101 words
A solar energy receiver for use with focused solar energy comprising: a housing having an open end, said housing adapted to be oriented such that focused sunlight passes through said open end, a heat exchanger within said housing having a number of channels, said channels opened towards said aperture, and, means for directing fluid flow through said channels such that when solar energy is focused onto said heat exchanger said fluid is heated, the heat exchanger temperature vs. channel length profile being relatively flat and substantially horizontal, whereby said heat exchanger is exposed to minimum thermal shock without sacrifice to efficiency.
Claim 29
Dependent Claim
101 words
A solar energy receiver for use with focused solar energy comprising: a housing having an open end, said housing adapted to be oriented such that focused sunlight passes through said open end, a heat exchanger within said housing having a number of channels, said channels opened towards said aperture, and, means for directing fluid flow through said channels such that when solar energy is focused onto said heat exchanger said fluid is heated, the heat exchanger temperature vs. channel length profile being relatively flat and substantially horizontal, whereby said heat exchanger is exposed to minimum thermal shock without sacrifice to efficiency.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-23 | 1982-04-24 | 1982-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-23 | 1986-04-24 | 1986-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-23 | 1990-04-24 | 1990-10-24 | $7700.00 | Window Closed / Lapsed |