Planar Reflectors[edit | edit source]
H. Tabor, "Mirror boosters for solar collectors," Solar Energy, vol. 10, Jul. , pp. 111-118.[edit | edit source]
J. Wennerberg, J. Kessler, J. Hedström, L. Stolt, B. Karlsson, and M. Rönnelid, "Thin film PV modules for low-concentrating systems," Solar Energy, vol. 69, Jul. , pp. 243-255.[edit | edit source]
* applying low concentration to CIGS technology * discusses using CPC or planar reflectors * references previous work by in sweden of use of planer reflectors * discusses non-uniform illumination with respect to CIGS * effects of temp and light intensity on CIGS * experimental work is done with CPCs at 4x concentration
S.C. Seitel, "Collector performance enhancement with flat reflectors," Solar Energy, vol. 17, Nov. 1975, pp. 291-295.[edit | edit source]
* Specular and diffused flat reflectors to enhance collector performance. * Moving reflector and Steady collector. * Discusses direct power equations for direct radiation and reflected radiation ( Specular and Diffused). * discusses factors such as Solar Intensity, Absorptivity, Reflectivity, Exchange Factor, Angle Factor. * Defines: Solar Intensity, Absorptivity, Reflectivity, Exchange Factor, Angle Factor. * FORTRAN routine is used to develop results . * Analysis of energy absorbed with respect to the included angle. * Observed the behavior of Angle factor with respect to included angle. * references work from The Franklin Institute and books on Thermal Radiation and heat transfer.
D. Larson, "Optimization of flat-plate collector-flat mirror systems," Solar Energy, vol. 24, 1980, pp. 203-207.[edit | edit source]
A.A. Al-Baali, "Improving the power of a solar panel by cooling and light concentrating," Solar & Wind Technology, vol. 3, 1986, pp. 241–245.[edit | edit source]
* Cooling system and concentration on normal PV panels * three PV panels (33 cells in series) o 1 solar panel, no accessories ; o 1 solar panel + reflecting plane mirror ; o 1 solar panel + reflecting plane mirror + water * temperature measured - thermocouple connected to YSI-47 Tc thermometer * ambient temp as high as 50C * cooling system fix panel temp at 35 to 45 C
H.P. Garg and D.S. Hrishikesan, "Enhancement of solar energy on flat-plate collector by plane booster mirrors," Solar Energy, vol. 40, 1988, pp. 295–307.[edit | edit source]
* flat collector tilted and two reflectors. * 2 reflectors ( north and south) and a collector in the middle. * Specular reflections, multiple reflections not considered * reflector-reflector shading neglected * Calculations using vectors and coordinate system ( pretty complex) * No change in absorbed energy tilting the collector. * references are very good and useful
A.V. Narasimha Rao, R.V. Chalam, S. Subramanyam, and T.L. Sitharama Rao, "Energy contribution by booster mirrors," Energy Conversion and Management, vol. 34, 1993, pp. 309–326.[edit | edit source]
* theoretical model created for using (top, bottom, or wing mirrors) * 3d model determines area illuminated and shadowed by reflector * computer code used beam radiation values calculated by Hottel's (model of clear sky atmospheric transmittance) * algorithms can be applied to 3d model for PV reflector
B. Perers and B. Karlsson, "External reflectors for large solar collector arrays, simulation model and experimental results," Solar Energy, vol. 51, 1993, pp. 327-337.[edit | edit source]
* high lattitudes -> large row spacing * 2D model to be used for FP or CPC reflectors * Diffuse treated isotropic -> using view factors -> described in Duffie * theoretical o infinite collector rows / reflectors o 4 cases of reflection for specular o explained for CPCs as wel o for finite lengths a correction factor is used o CPCs are 15% better for same reflector / collector width ratio * experimental o Four identical 11m^2 flat plate collector modules o one was used as reference o three equipped with external reflectors of w = 3m and L= 7m o collector w = 2.4m and L= 5m * An annual performance increase of over 30% - four operating seasons in the Scandinavian climate (latitude 60 ° )
A.V. Rao, S. Subramanyam, and T.L. Rao, "Performance of east/west plane booster mirror," Energy Conversion and Management, vol. 35, 1994, pp. 543–554.[edit | edit source]
* East/west mirrors are used (FP reflector on top of collector) * thermal system and looks into the performance increase * increases the fill factor (thermally) * optimal mirror angle calculated (latitudes of 0 to 40 N)
M. Rönnelid, B. Karlsson, P. Krohn, and J. Wennerberg, "Booster reflectors for PV modules in Sweden," Progress in Photovoltaics: Research and Applications, vol. 8, 2000, pp. 279–291.[edit | edit source]
* benefits of having planer reflectors in row spacing * discusses temp increase problem and potential solutions * no cooling is done in study * looks at reflector geometry and annual changes * 20% increase in output in one test -> drop to 0 when panel half covered * A-Si is better an dealing with uneven illumination * 20-25% increase -> 40% if 8 annual adjustments are made
Y. Tripanagnostopoulos, M. Souliotis, and T. Nousia, "Solar collectors with colored absorbers," Solar Energy, vol. 68, 2000, pp. 343-356.[edit | edit source]
* Solar Thermal Collectors used for water heating applications * Performance results of three FP solar collectors: black, blue and red brown absorbers (with or without glazing) * Used polished stainless steel thin sheet reflectors (0.68 reflectivity)
V. Poulek and M. Libra, "A new low-cost tracking ridge concentrator," Solar Energy Materials and Solar Cells, vol. 61, Mar. 2000, pp. 199-202.[edit | edit source]
* Panel on either side of two flat booster mirrors back to back * one axis tracking throughout day * seasonal tracking by adjusting slope of axle * recommend use of rolled aluminum alloy sheet (protected by weather resistant polymer) * concentration ratio of 1.6 to 1.7 * Clear day -> energy surplus of 107%
M.D.J. Pucar and A.R. Despic, "The enhancement of energy gain of solar collectors and photovoltaic panels by the reflection of solar beams," Energy, vol. 27, Mar. 2002, pp. 205-223.[edit | edit source]
- reflectors on upper edge of the receivers considered
- Continuously adjustable reflecting panels - higher costs - higher efficiencies - are analyzed
- Only theoretical - no testing of devices
- Computed for PV panel at 44° NL (Belgrade, Yugoslavia) - inclined at 35° wrt horizontal
- Modeled for 4 days: 21 December, 21 March/September ,21 June
- 5 different types of reflectors (tracking - both horizontally and vertically)
T. Matsushima, T. Setaka, and S. Muroyama, "Concentrating solar module with horizontal reflectors," Solar Energy Materials and Solar Cells, vol. 75, Feb. 2003, pp. 603-612.[edit | edit source]
* proposed module and reflector setup * reflector: width of reflector is 2x, length is 2.7x that of panel * test conducted in solar simulator * tests conducted outdoors o short circuit measured throughout day o compared to conventional module * power output determination did not seem to take into acount efficiency drops * estimated power generation increase of 1.5 times (seems very high - no losses)
H. Tanaka, "Solar thermal collector augmented by flat plate booster reflector: Optimum inclination of collector and reflector," Applied Energy, vol. 88, Apr. 2011, pp. 1395-1404.[edit | edit source]
* Solar thermal collector with FP top reflector * adjustable inclination of reflector for seasons * looked at shading effects of top reflector * determined optimal angles and adjustments for angle throughout year
I. S. Taha and S. M. Eldighidy, Effect of off-south orientation on optimum conditions for maximum solar energy absorbed by flat plate collector augmented by plane reflector. Solar Energy 25, 373 (1980).[edit | edit source]
S.L. Grassie, N.R. Sheridan, The use of planar reflectors for increasing the energy yield of flat-plate collectors, Solar Energy. 19 (1977) 663-668.[edit | edit source]
* presents a derivation of view factor for use with diffuse reflectors, this could possibly be used to estimate the diffuse radiation boost. * diffuse reflector estimated by use of a white painted sheet.Had a negligable effect * also presents optical derivation for light * 14% increase due to reflector * reflector above the panel is good for winter time, below is good for summer
Joseph W.Bollentin, Richard D.Wilk, Modeling the solar irradiation on flat plate collectors augmented with planar reflectors, Solar Energy, Vol. 55, Issue 5, November 1995, pp. 343-354.[edit | edit source]
D. McDaniels, D. Lowndes, H. Mathew, J. Reynolds, R. Gray, Enhanced solar energy collection using reflector-solar thermal collector combinations, Solar Energy. 17 (1975) 277-283.[edit | edit source]
* H.Thomanson, energy increase of 30% * non-specular mirrors used by sherman, babor and others [11-15] * Solar collector mounted vertically * Includes correlation for reflectance at large angles of incidence * Takes into account beam and diffuse radiation * preliminary impovment of 1.6+/-0.6 over straight collector * uses spectrally averaged data for reflectivity, 0.9 new 0.7 weathered, coated with SiO * optimum performance when angle between panel and reflector is 90 degrees * focus on winter improvement * recommends reflector length of twice the height of the panel in winter, 1.6 in summer * good graph showing enhancement factor of the arr
Low Concentration[edit | edit source]
K.G.T. Hollands, "A concentrator for thin-film solar cells," Solar Energy, vol. 13, 1971, pp. 149–163.[edit | edit source]
- Discusses use of V-trough concentrators for PV
- Tracks seasonal but notdiurnal motion of sun – several times per year
- Direct-beam concentration factor determined as function of incidence angle of solar beam, side-wall reflectance and opening angle of trough.
- Firstly, it assumes the side walls to be perfectly specular, gray surfaces. Secondly, it restricts the trough geometries studied to those where, with the solar beam normal to the base, two conditions are met: (a) the base is uniformly irradiated; (b) no ray suffers more than one reflection.
K.G. Hollands and R.G. Huget, "A probability density function for the clearness index, with applications," Solar Energy, vol. 30, 1983, pp. 195–209.[edit | edit source]
R. Perez, R. Seals, P. Ineichen, R. Stewart, and D. Menicucci, "A new simplified version of the Perez diffuse irradiance model for tilted surfaces," Solar energy, vol. 39, 1987, pp. 221–231.[edit | edit source]
G. Whitfield, R. Bentley, C. Weatherby, A. Hunt, H. Mohring, F. Klotz, P. Keuber, J. Miñano, and E. Alarte-Garvi, "The development and testing of small concentrating PV systems," Solar Energy, vol. 67, Jul. 1999, pp. 23-34.[edit | edit source]
R.M. Swanson, "The promise of concentrators," Progress in Photovoltaics: Research and Applications, vol. 8, 2000, pp. 93–111.[edit | edit source]
Abstract: This paper addresses the issue of why concentrator systems have not gained a significant market share. The history of concentrator development is reviewed, and the status of existing concentrator efforts outlined. A critical look at the requirements to propel concentrators to a prominent market role in large-scale power production is presented. Various concentrator and ¯at-plate PV system approaches are compared by computing the expected cost of energy, and conclusions are drawn as to what the best course of action will be. Concentrator systems are projected to be the lowest-cost, lowest-risk PV option for medium and large PV power plants.
- Discusses policies and history behind concentration in solar
- Growth of concentration and it's relation to the oil crisis of the 80s
- Discusses the future
M. Mehos, A. Lewandowski, M. Symko-Davies, and S. Kurtz, "Concentrating Photovoltaics: Collaborative Opportunities within DOE's CSP and PV Programs," NCPV Program Review Meeting, Lakewood, Col., USA, October, 2001, pp. 14–17.[edit | edit source]
J. Nilsson, "Optical Design and Characterization of Solar Concentrators for Photovoltaics," Lund Univeristy, 2005.[edit | edit source]
- A thorough thesis
- Covers different reflectors for concentration
- Mathematical models to represent them
