S PA CE R ESEA RCH I N ST IT U T E Comparison of Photovoltaic Modeling Analysis and Actual Performance Data of Lee County Justice Center Solar Power Installation Project Julie A. Rodiek and Steve R. Best Space Research Institute, Auburn University Henry W. Brandhorst, Jr. Carbon-Free Energy, LLC July 28, 2010 8 th International Energy Conversion Engineering Conference Space Research Institute
S PA CE Outline R ESEA RCH I N ST IT U T E Project Overview Objectives Why Now Initial Modeling System Component Selection System Modeling Data Collection and Analysis Summary 8 th International Energy Conversion Engineering Conference Space Research Institute
S PA CE Project Overview R ESEA RCH I N ST IT U T E Lee County’s TK Davis Justice Center (LCJC) awarded grant from Alabama Department of Economic and Community Affairs (ADECA) to install an expandable system of photovoltaic solar panels » Initial installation consists of a 16.6 kW grid-connected PV system » Will offset some of the energy costs of electricity used by the LCJC Auburn University working with LCJC to determine the optimal photovoltaic system » Site and system limitations » Installation planning/oversight » Performance Analysis » Monitoring and assessment 8 th International Energy Conversion Engineering Conference Space Research Institute
S PA CE Objectives of Project R ESEA RCH I N ST IT U T E Compare actual power performance to modeled predictions Determine reasons behind variations between programs » Monitor the performance of this system along with weather and environmental factors Information gathered through the system’s design, installation, and monitoring will provide valuable information concerning photovoltaic alternative energy systems on public facilities Use as a prototype for other similar undertakings » Used different mounting options and tilt angles » Excellent teaching and demonstration tool Showcase for potential solar installations at other facilities Establish a message that local governments need to take an active role in increasing energy-efficiency and environmental sensitive building designs while reducing operational costs for its citizens over the long-term 8 th International Energy Conversion Engineering Conference Space Research Institute
S PA CE Why Now… R ESEA RCH I N ST IT U T E Increasing energy costs Reduce the U.S. reliance on foreign oil and also the need for new power plants fueled by coal or oil Upsurge has taken place in the use of cost-competitive photovoltaic technologies for terrestrial applications Existing 30% U.S. Government tax credit for installing photovoltaic (PV) and/or solar hot water systems coupled with tax incentives in a few states Why NOT now….electricity is cheap in Alabama, lack of certified in-state installers, no state incentives 8 th International Energy Conversion Engineering Conference Space Research Institute
S PA CE What About Sunshine In AL? R ESEA RCH I N ST IT U T E Al has ~20% less sunlight than the best in the SW Plenty of sunshine Power is produced on » rainy day too Al is better than the NE, with major new installations now 8 th International Energy Conversion Engineering Conference Space Research Institute
Solar Array System Analysis S PA CE R ESEA RCH I N ST IT U T E Load Monitoring Electronic load monitoring and data logging of some load center panels in the Central Utility Plant of the LCJC were made Help determine the load placed on PV arrays » Illustrates the hourly and daily variations in » the electrical load demands of this one circuit Continuous operation: 24hr / 7day » Peaks nominally during daylight hours » matching the generation capability of the photovoltaic array very well Used as input to a solar power modeling program to project system performance, help optimize design, and compare to predicted performance Electrical inverter specifications determined 8 th International Energy Conversion Engineering Conference Space Research Institute
Solar Array System Analysis S PA CE R ESEA RCH I N ST IT U T E PV Module Comparison Study done of the types and performance of 7.00 photovoltaic modules that are currently 6.00 5.00 available in the market 4.00 Comparison of PV modules ratio to highest » $/Watt 3.00 power 2.00 mc-Si Modules Cost to power ratio was also calculated 1.00 c-Si Modules » 0.00 When choosing the photovoltaic panels it is a 100 150 200 250 300 350 Watts decision of efficiency versus cost 20.00 18.00 16.00 14.00 12.00 Watts/(Ft^2) 10.00 8.00 mc-Si Modules 6.00 4.00 C-Si Modules 2.00 0.00 600 700 800 900 1000 1100 1200 1300 Dollars 8 th International Energy Conversion Engineering Conference Space Research Institute
Solar Array System Analysis S PA CE R ESEA RCH I N ST IT U T E CAD Model of LCJC Detention Center Google Earth & SketchUp used » Aerial site photo imported into Google SketchUp from Google Earth » Geographical data conserved » DoE EnergyPlus plugin: OpenStudio Photo used to generate CAD model Building outlines & elevations added Roof equipment detail added as needed 8 th International Energy Conversion Engineering Conference Space Research Institute
Solar Array System Analysis S PA CE R ESEA RCH I N ST IT U T E CAD Model of LCJC Detention Center Large, mostly unobstructed north/south-aligned flat roof Room to install now and/or expand in future Some public visibility is important to this installation 8 th International Energy Conversion Engineering Conference Space Research Institute
Solar Array System Analysis S PA CE R ESEA RCH I N ST IT U T E Shadow Study Analysis on Roof Mounts w/SketchUp Winter Solstice Summer Solstice 8 th International Energy Conversion Engineering Conference Space Research Institute
Solar Array System Analysis S PA CE R ESEA RCH I N ST IT U T E PV Design Pro-G Modeling Selected Inputs 220 W SunPower Panels » 480 V Solectria PVI-13kW Inverter » 30-year weather profile database for » Montgomery, Ala. East – West tracking system » Fixed tilt of 30 degrees 35.5% of the annual load for specified circuit is produced by PV energy Annual total of energy provided to the load of 40,634 kWh All of the energy generated by the system cannot be used by this load Automatically shifts the excess power to another circuit so all the power » generated by the array will be used within the facility 8 th International Energy Conversion Engineering Conference Space Research Institute
S PA CE Angle Study at Auburn University R ESEA RCH I N ST IT U T E Test the accuracy of solar modeling programs Discrepancy may be due to the way each program applies the angle tilt of the array thereby » calculating solar irradiance to estimate the power production There are six test panels Five panels rotated in a single axis at the tilt angles of 20º, 25º, 32º (latitude), 40º, and 50º » Another panel will be a control panel that is fixed facing south at latitude tilt » 8 th International Energy Conversion Engineering Conference Space Research Institute
S PA CE LCJC PV Array Project Layout R ESEA RCH I N ST IT U T E 8 th International Energy Conversion Engineering Conference Space Research Institute System completion and certification, June 29, 2009
S PA CE Balance of the PV System R ESEA RCH I N ST IT U T E Inverters are used to convert solar array DC to utility-quality AC Roof Array: Solectria PVI-13kW 480 VAC, 3- » phase Inverter output from Solectria’s SolrenView site Pole Array: SunPower SPR3000m 3kW, 208 » VAC Inverter output from SMA’s SunnyPortal site SMA’s WebBox and SensorBox collect both » roof and pole array environment data onto SMA’s SunnyPortal : Solar irradiance Module temperature Ambient air temperature Wind speed Performance data are used to monitor system and compare to model predictions 8 th International Energy Conversion Engineering Conference Space Research Institute
S PA CE System Modeling R ESEA RCH I N ST IT U T E PV Design Pro-G, PV Watts, and PVSYST used for analysis of system Each program different » » Some are more detailed on inputable parameters Highest power performance prediction PVSYST for pole array » PV Design Pro G for roof array » Roof Array Pole Array PVSYST Design Pro G PV Watts PVSYST Design Pro G PV Watts Jan 1100 1203 1162 161 189 175 Feb 1156 1366 1288 163 201 182 Mar 1496 1805 1745 197 250 230 Apr 2132 2044 1982 265 263 243 May 2320 2160 1958 273 263 227 Jun 2264 2028 1887 261 240 213 Jul 2225 2063 1889 260 246 216 Aug 2245 2018 1797 273 252 216 Sep 1888 1817 1639 243 242 210 Oct 1803 1691 1615 252 245 224 Nov 1325 1290 1233 197 199 183 Dec 1220 1174 1082 188 190 165 Yearly Production 21,174 20,659 19,277 2732 2777 2484 8 th International Energy Conversion Engineering Conference Space Research Institute
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