Get our free book (in Spanish or English) on rainwater now - To Catch the Rain.
Optimizing reflector orientation for a solar panel at various latitudes
| By Michigan Tech's Open Sustainability Technology Lab.
Wanted: Students to make a distributed future with solar-powered open-source 3-D printing.
- 1 Contributors
- 2 Intro
- 3 Searches
- 4 Literature Review
- 4.1 Stationary reflector-augmented flat-plate collectors - 1981
- 4.2 Modeling daylight availability and irradiance components from direct and global irradiance - 1990
- 4.3 A Comprehensive Physical Model for Light Reflection - 1991 
- 4.4 Feasibility study of one axis three positions tracking solar PV with low concentration ratio reflector
- 4.5 Solar thermal collector augmented by flat plate booster reflector: Optimum inclination of collector and reflector - 2011
- 4.6 Optimal position of flat plate reflectors of solar thermal collector-2011
- 4.7 Photovoltaic System Performance Enhancement With Nontracking Planar Concentrators: Experimental Results and Bidirectional Reflectance Function (BDRF)-Based Modeling - 2013/2015  
- 5 Bibliography
The angle of incidence of solar rays is different at different latitudes. Therefore, using the same angle of inclination for concentrators will not help in acquiring best solar energy capture. What we aim to do in this project is obtain the optimal positioning of concentrators for 6 cases of latitude ranging from 10-60 degrees with an increment of 10 degrees. For each of the latitude cases, we will consider 9 inclination angles of the PV panels ranging from 0-90 degrees with an increment of 15 degrees and test the position of concentrators aiming to obtain best energy yield. We will simulate 6 angles for the concentrators ranging from 10-60 degrees with 10 degrees increment to find the optimal solution. We ultimately want to generate a thumb of rule from this experiment.
- low concentration solar reflectors
The papers reviewed for the completion of this project have been listed below in chronological order of publication. Included are brief summaries of each.
Abstract-A general procedure for determining the optimum geometry of a reflector-augmented solar collector which produces a desired pattern of flux-augmentation is described. The example used for illustration is a stationary collector whose winter performance is to be improved. Consideration of both a flat-plate collector with a bottom reflector and one with a top reflector led to distinct differences in their optimum configuration and performance being identified. Since either systems can be used to augment winter flux, a criterion for selecting the appropriate system is given. This criterion is based on the displacement in collector tilt from latitude inclination.
- performance factors - reflector width ratio, reflector angle, panel tilt angle from latitude
- performance curves to decide b/w top- and bottom-reflectors.
- unity reflector width ration suggested.
Modeling daylight availability and irradiance components from direct and global irradiance - 1990
Abstract - This paper presents the latest versions of several models developed by the authors to predict short time-step solar energy and daylight availability quantities needed by energy system modelers or building designers. The modeled quantities are global, direct and diffuse daylight illuminance, diffuse irradiance and illuminance impinging on tilted surfaces of arbitrary orientation, sky zenith luminance and sky luminance angular distribution. All models are original except for the last one which is extrapolated from current standards. All models share a common operating structure and a common set of input data: Hourly (or higher frequency) direct (or diffuse) and global irradiance plus surface dew point temperature. Key experimental observations leading to model development are briefly reviewed. Comprehensive validation results are presented. Model accuracy, assessed in terms of root-mean-square and mean bias errors, is analyzed both as a function of insolation conditions and site climatic environment.
- Models for predicting relevant quantities like solar energy in short intervals and availability of light - can be used for specific user needs.
- First model relates irradiance value to the light from sun/sky as comprehended by the human eye.
- Second approximates illuminance and irradiance for horizontally surface tilted.
- Third - angular distribution of light instead of the diffuse values.
Abstract - A new general reflectance model for computer graphics is presented. The model is based on physical optics and describes specular, directional diffuse, and uniform diffuse reflection by a surface. The reflected light pattern depends on wavelength, incidence angle, two surface roughness parameters, and surface refractive index. The formulation is self consistent in terms of polarization, surface roughness, masking/shadowing, and energy. The model applies to a wide range of materials and surface finishes and provides a smooth transition from diffuse-like to specular reflection as the wavelength and incidence angle are increased or the surface roughness is decreased. The model is analytic and suitable for Computer Graphics applications. Predicted reflectance distributions compare favorably with experiment. The model is applied to metallic, nonmetallic, and plastic materials, with smooth and rough surfaces.
- Light reflection explained
- Components of light reflection
Feasibility study of one axis three positions tracking solar PV with low concentration ratio reflector
Abstract - A new PV design, called “one axis three position sun tracking PV module”, with low concentration ratio reflector was proposed in the present study. Every PV module is designed with a low concentration ratio reflector and is mounted on an individual sun tracking frame. The one axis tracking mechanism adjusts the PV position only at three fixed angles (three position tracking): morning, noon and afternoon. This “one axis three position sun tracking PV module” can be designed in a simple structure with low cost. A design analysis was performed in the present study. The analytical results show that the optimal stopping angle β in the morning or afternoon is about 50° from the solar noon position and the optimal switching angle that controls the best time for changing the attitude of the PV module is half of the stopping angle, i.e. θH = β/2, and both are independent of the latitude. The power generation increases by approximately 24.5% as compared to a fixed PV module for latitude ϕ < 50°. The analysis also shows that the effect of installation misalignment away from the true south direction is negligible (<2%) if the alignment error is less than 15°. An experiment performed in the present study indicates that the PV power generation can increase by about 23% using low concentration (2X) reflectors. Hence, combining with the power output increase of 24.5%, by using one axis three position tracking, the total increase in power generation is about 56%. The economic analysis shows that the price reduction is between 20% and 30% for the various market prices of flat plate PV modules.
- switching angle and stopping angle independent of latitude
- reflectors at 60 degrees to panel
- power increase with reflectors
Solar thermal collector augmented by flat plate booster reflector: Optimum inclination of collector and reflector - 2011
Abstract - In this report we present a theoretical analysis of a solar thermal collector with a flat plate top reflector. The top reflector extends from the upper edge of the collector, and can be inclined forwards or backwards from vertical according to the seasons. We theoretically predicted the daily solar radiation absorbed on an absorbing plate of the collector throughout the year, which varies considerably with the inclination of both the collector and reflector, and is slightly affected by the ratio of the reflector and collector length. We found the optimum inclination of the collector and reflector for each month at 30°N latitude. An increase in the daily solar radiation absorbed on the absorbing plate over a conventional solar thermal collector would average about 19%, 26% and 33% throughout the year by using the flat plate reflector when the ratio of reflector and collector length is 0.5, 1.0 and 2.0 and both the collector and reflector are adjusted to the proper inclination.
- opt. inclination yearlong (collector+flat top reflector) for 30°N - theoritically.
- new graphical method for irradiation through reflection.
- Angle of reflector inclination - forward in winter/backward in summer (less than 30°). Directly affected by ratio of collector & reflector length.
- Collector Incli. - lower in summer/higher in winter. Not affected much by length ratio.
Abstract - In this paper the results of the influence of position of the flat plate reflectors made of Al sheet on thermal efficiency of solar thermal collector with spectrally selective absorber are presented. Analytical and experimental results on determination of the optimal position of flat plate solar reflectors during the day time over the whole year period are shown. Both numerical calculation and experimental measurements indicate that optimal angle position of the bottom reflector is the lowest (5°) in December and the highest (38°) in June for collector fixed at β = 45° position. The thermal efficiency of thermal collector without reflectors and with reflectors in optimal position has been determined. Though the thermal efficiency of thermal collector decreases slightly with the solar radiation intensity, the total thermal energy generated by thermal collector with reflectors in optimal position is significantly higher than total thermal energy generated by thermal collector without reflectors. These results show the positive effect of reflectors made of Al sheet and there is an energy gain in the range 35–44% in the summer period for thermal collector with reflectors, which is expected to reduce the cost pay back time.
- Experiment Setup: top- and bottom- Al sheet reflectors; collector 45 degrees inclination. Coordinates (43°19′N, 21°54′E)
- Analytical model for day time - whole year | Compared with and w/o reflectors
- Total solar irradiation = direct radiation (collector) + reflected radiation (top & bottom) + diffuse radiation (mathematical equations given)
- Increased energy yield; decreased thrmal efficiency.
Photovoltaic System Performance Enhancement With Nontracking Planar Concentrators: Experimental Results and Bidirectional Reflectance Function (BDRF)-Based Modeling - 2013/2015  
Abstract - Nontracking planar concentrators are a low-cost method of increasing the performance of traditional solar photovoltaic (PV) systems. This paper presents new methodologies for properly modeling this type of system using a bidirectional reflectance function for nonideal surfaces rather than traditional geometric optics. This methodology allows for the evaluation and optimization of specular and nonspecular reflectors in planar concentration systems. In addition, an outdoor system has been shown to improve energy yield by 45% for a traditional flat glass module and by 40% for a prismatic glass crystalline silicon module when compared with a control module at the same orientation. When compared with a control module set at the optimal tilt angle for this region, the energy improvement is 18% for both systems. Simulations show that a maximum increase of 30% is achievable for an optimized system located in Kingston, ON, Canada, using a reflector with specular reflection and an integrated hemispherical reflectance of 80%. This validated model can be used to optimize reflector topology to identify the potential for increased energy harvest from both existing PV and new-build PV assets.
- Two papers Same name - 2nd derived from 1st
- new irradiance model - BRDF based
- calculate irradiance-then module output (Isc) | obtain cell temperature-estimate power
- 2nd paper - optimal module arrangement for Kingston (44.2312° N, 76.4860° W) - energy yield 18% up
- H. Chiam, "Stationary reflector-augmented flat-plate collectors," Solar Energy, vol. 29, no. 1, pp. 65-69, 1982.
- R. Perez, P. Ineichen, R. Seals, J. Michalsky, and R. Stewart, "Modeling daylight availability and irradiance components from direct and global irradiance," Solar Energy, vol. 44, no. 5, pp. 271-289, 1990
- X. D. He, K. E. Torrance, F. X. Sillion, and D. P. Greenberg, "A comprehensive physical model for light reflection," SIGGRAPH Comput. Graph., vol. 25, no. 4, p. 175186, Jul. 1991
- B.J. Huang, F.S. Sun, "Feasibility study of one axis three positions tracking solar PV with low concentration ratio reflector", Energy Conversion and Management, vol. 48, Issue 4, pp. 1273-1280, April 2007.
- Hiroshi Tanaka, Solar thermal collector augmented by flat plate booster reflector: Optimum inclination of collector and reflector, Applied Energy, Volume 88, Issue 4, April 2011, Pages 1395-1404, ISSN 0306-2619, http://dx.doi.org/10.1016/j.apenergy.2010.10.032
- L. T. Kosti, Z. T. Pavlovi, "Optimal position of flat plate reflectors of solar thermal collector", Energy Buildings, vol. 45, pp. 161-168, Feb. 2012.
- R. W. Andrews, A. Pollard and J. M. Pearce, "Photovoltaic System Performance Enhancement With Nontracking Planar Concentrators: Experimental Results and Bidirectional Reflectance Function (BDRF)-Based Modeling," in IEEE Journal of Photovoltaics, vol. 5, no. 6, pp. 1626-1635, Nov. 2015, doi: 10.1109/JPHOTOV.2015.2478064
- R. W. Andrews, A. Pollard and J. M. Pearce, "Photovoltaic system performance enhancement with non-tracking planar concentrators: Experimental results and BDRF based modelling," 2013 IEEE 39th Photovoltaic Specialists Conference (PVSC), Tampa, FL, 2013, pp. 0229-0234, doi: 10.1109/PVSC.2013.6744136