Free-hanging parabolic trough reflectors for solar energy conversion systems
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H01L-031/052
H02S-040/42
H02S-040/22
H01L-031/054
H02S-020/32
H02S-040/44
F24J-002/00
G02B-005/08
G02B-007/18
G02B-017/00
출원번호
US-0437272
(2017-02-20)
등록번호
US-10001297
(2018-06-19)
발명자
/ 주소
Ganley, James T
출원인 / 주소
Ganley, James T
인용정보
피인용 횟수 :
0인용 특허 :
10
초록▼
A parabolic trough reflector assembly consists of (1) a free-hanging, flexible rectangular sheet that is highly reflective of solar radiation and (2) support hardware which critically supports the reflecting sheet at two opposing edges. Methods are disclosed for providing linear dimensions and edge
A parabolic trough reflector assembly consists of (1) a free-hanging, flexible rectangular sheet that is highly reflective of solar radiation and (2) support hardware which critically supports the reflecting sheet at two opposing edges. Methods are disclosed for providing linear dimensions and edge slopes for the reflecting sheet that are consistent with a parabolic trough having specific predetermined dimensions and a predetermined focal length. Methods are disclosed for providing uniform loading for a reflecting sheet when it is critically supported as a free-hanging element. The methods involve tapering the thickness of a sheet, applying variable-thickness coatings to a sheet of uniform thickness, or fabricating discreet thickness variations into a sheet of otherwise uniform thickness.
대표청구항▼
1. A parabolic trough reflector assembly comprising a) a flexible sheet having a mass distribution that provides uniform loading for said sheet when it is critically supported as a free-hanging element, and with said sheet having longitudinal and transverse dimensions that are compatible with formin
1. A parabolic trough reflector assembly comprising a) a flexible sheet having a mass distribution that provides uniform loading for said sheet when it is critically supported as a free-hanging element, and with said sheet having longitudinal and transverse dimensions that are compatible with forming, through the process of critically supporting said sheet as a free-hanging element, a free-hanging parabolic trough reflector characterized by i) a highly reflective concave surface whose transverse sections are, at every longitudinal location, identical parabolas, andii) a predetermined system-specific value of longitudinal length, L, with said longitudinal length being the distance measured horizontally between the two unsupported edges of said free-hanging parabolic trough reflector, andiii) a predetermined system-specific value of transverse width, W, with said transverse width being the distance measured horizontally between the two supported edges of said free-hanging parabolic trough reflector, andiv) a predetermined system-specific value of focal length, F;b) support fixtures which secure, hold, and critically support two opposing longitudinal edges of said sheet, with said support fixtures establishing and maintaining the relative orientation and position of the two supported edges of said sheet so that said supported edges are parallel to each other and in the same horizontal plane, and with said support fixtures having a horizontal spacing that is equal to W, the predetermined system-specific value of transverse width of said parabolic trough reflector that is formed by critically supporting said sheet as a free-hanging element, and with said support fixtures holding and securing the two supported edges of said sheet in such a manner that the edge slope at one supported edge of said sheet has a value of +W/4F and the edge slope at the other supported edge of said sheet has a value of −W/4F, where W and F, respectively, are the predetermined system-specific values of transverse width and focal length of said parabolic trough reflector. 2. The assembly of claim 1 with said sheet having a longitudinal dimension that is equal in length to the predetermined system-specific value of longitudinal length, L, of said parabolic trough reflector that is formed when said sheet is critically supported as a free-hanging element; and with said sheet having a transverse dimension that is equal in length to the extended parabolic arc length, SE, of said parabolic trough reflector that is formed when said sheet is critically supported as a free-hanging element; and with said parabolic trough reflector having a predetermined system-specific value of clamping width, WCL, transverse width, W, and focal length, F, which together define the value of said extended parabolic arc length, SE, through the relationship SE=2WCL+ST, where ST, the total parabolic arc length of said parabolic trough reflector is defined by the relationship ST=(W/8F)(16F2+W2)1/2+(2F)loge[(W/4F)+(¼F)(16F2+W2)1/2]. 3. The assembly of claim 2, wherein uniform loading is provided for said sheet when it is critically supported as a free-hanging element, with said uniform loading provided for said sheet by tapering its thickness from a maximum value T0 along its longitudinal centerline to a lesser value at its supported edges; with the transverse thickness profile of said sheet being the same for all transverse sections of said sheet; and with the transverse thickness profile of said sheet defined parametrically in terms of a parameter “A” which takes on all values in the range 0≤A≤W/2; and with T(A), the thickness of said sheet, defined as T(A)=2FT0(4F2+A2)−1/2; and with D(A), the distance between the longitudinal centerline of said sheet and points at which said sheet has thickness T(A) being defined as D(A)=A(4F)−1(4F2+A2)1/2+(F)loge[A(2F)−1+(2F)−1(4F2+A2)1/2], with the same value of A used in calculating thickness values, T(A), and corresponding distance values, D(A), between the longitudinal centerline of said sheet and points at which said sheet has thickness T(A); and with the thickness of said sheet, T(A), therefore being the same at all points that are a distance D(A) from the longitudinal centerline of said sheet. 4. The assembly of claim 2, wherein uniform loading is provided for said sheet when it is critically supported as a free-hanging element, and with said uniform loading being provided to said sheet by applying a variable thickness coating to said sheet; with said sheet having initially uniform thickness, T0, and uniform density, ρSH; and with said coating having a uniform density, ρC; and with said coating having a transverse thickness profile TC(A) that is the same for all transverse sections of said sheet; and with said transverse thickness profile TC(A) of said coating defined parametrically in terms of a parameter “A” which takes on all values in the range 0≤A≤W/2; and with said thickness profile TC(A) of said coating defined as TC(A)=(ρSH/ρC)(T0/2)[(16F2+W2)1/2(4F2+A2)−1/2−2]; and with D(A), the distance from the centerline of said sheet to points at which said coating has thickness TC(A), being defined as D(A)=A(4F)−1(4F2+A2)1/2+(F)loge[A(2F)−1+(2F)−1(4F2+A2)1/2]; with the same value of A used in calculating said thickness values, TC(A), and corresponding values of said distance, D(A), from the centerline of said sheet to points at which said coating has thickness TC(A); and with the thickness of said coating, TC(A), therefor being the same at all points that are a distance D(A) from the longitudinal centerline of said sheet. 5. The assembly of claim 2, wherein discontinuous loading is provided for said free-hanging sheet by creating discrete, stepwise variations in said sheet's thickness; with said discrete, stepwise thickness variations produced by machining or molding longitudinal channels into the back surface of said sheet; and with the width, depth, and spacing of said channels providing thickness variations which, when averaged from channel to channel, approximate a continuous transverse thickness profile which would provide uniform loading for said sheet. 6. The assembly of claim 2, wherein discontinuous loading is provided for said free-hanging sheet by creating discrete, stepwise variations in the sheet's thickness, with the discrete, stepwise thickness variations produced by applying a coating to longitudinal strips along the back surface of said sheet, and with the width, thickness, and spacing of said coated strips providing thickness variations which, when averaged from strip to strip, approximate the continuous transverse thickness profile which would provide uniform loading for said sheet. 7. The assembly of claim 1, wherein said free-hanging sheet has circular drainage holes disposed along its longitudinal centerline, with the edges of said drainage holes reinforced by circumferential lips, with said circumferential lips having a mass equal to the mass of material removed from the said sheet in creating said drainage holes, thus preserving the loading of said sheet that would exist if said drainage holes did not exist.
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이 특허에 인용된 특허 (10)
Korr Abraham L. (Philadelphia PA) Walker Evan H. (Aberdeen MD) Svihel Bernard T. (Laverock PA), Apparatus for the collection and conversion of solar energy.
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