Solar Position Algorithm Connected Components . - Rockwell Automation
Quick ReferenceSolar Position Algorithm Connected Components AcceleratorToolkitAbout This PublicationTopicPageAbout This Publication1Overview of Solar Positioning3Solar Position Algorithm Description4Validation and Test Results14Additional Resources16This quick reference provides instructions for using the Solar PositioningAlgorithm with Connected Components Workbench software in a solar trackingapplication. The algorithm is provided as part of the Connected ComponentsAccelerator Toolkit (CCAT).The CCAT is available on the Connected Components Accelerator ToolkitDVD, publication CC-QR002, or through the Rockwell Automation SoftwareDownload and Registration System (SDRD) ols/accelerator-toolkit.page.Before You BeginParameters related to geographical and environmental conditions of the observerwere taken from the National Renewable Energy Laboratory (NREL) SolarPositioning Algorithm Calculator website athttp://www.nrel.gov/midc/solpos/spa.html and used for validation of theuser-defined function block (UDFB).Investigate parameters for other geographical locations because they are likely tochange.
2 Solar Position Algorithm Connected Components Accelerator ToolkitWhat You NeedBecause the RA SOLAR POSITION ALGRTHM instruction requires morethan the standard amount of data memory to store temporary variables andconstants, we recommend that you use one of the specified range of controllers: Micro830 programmable controllers, 24-point base catalog numbers2080-LC30-24xxx and 48-point base catalog numbers 2080-LC30-48xxx Micro850 programmable controllers, 24-point base catalog numbers2080-LC50-24xxx and 48-point base catalog numbers 2080-LC50-48xxxIMPORTANTThis specified range of controllers is a guideline that is dependent on theextensiveness of your controller code.You also need the following: Personal computer Connected Components Workbench software, version 2.0 and later Standard USB for Micro830 controller Ethernet network connection for Micro850 controller onlyCCAT Solar Tracking Folder ContentsThe CCAT Solar Tracking Folder in the Sample Code Modules, contains thefollowing information: This Quick Reference document The National Renewable Energy Laboratory (NREL) Technical ReportNREL/TP-560-343-2 RA SOLAR POSITION ALGRTHM UDFB ConnectedComponents Workbench (CCW) exchange file in 7z format An application example showing the possible uses of theRA SOLAR POSITION ALGRTHM user-defined function block (ina zipped CCW project folder)Rockwell Automation Publication CC-QR005A-EN-P - May 2013
Solar Position Algorithm Connected Components Accelerator Toolkit 3Follow These StepsFollow these steps to implement the Solar Position Algorithm.StartOverview of Solar Positioning,page 3Solar Position AlgorithmDescription, page 4Solar Position Algorithm UDFB,page 6Use the Solar Position Algorithm,page 8Validation and Test Results,page 14Overview of Solar PositioningSolar trackers orient photovoltaic panels, reflectors, lenses, or other opticaldevices toward the sun. Since the sun’s position in the sky changes with theseasons and the time of day, trackers align the collection system to maximizeenergy production.Tracker control algorithms typically incorporate a control strategy that is a hybridbetween open-loop and closed-loop control. The open-loop components preventthe elimination of distortion of feedback signals from clouds that block the sun.The closed-loop components eliminate errors from variability in installation,assembly, calibration, and encoder mounting.Closed-loop systems track the sun with a set of lenses or sensors with a limitedfield of view, directed at the sun, and are fully illuminated by sunlight at all times.As the sun moves, it begins to shade one or more sensors. The system detects thismovement and activates motors or actuators to move the device back into aposition where all sensors are once again equally illuminated.Rockwell Automation Publication CC-QR005A-EN-P - May 2013
4 Solar Position Algorithm Connected Components Accelerator ToolkitOpen-loop systems typically employ electronic logic, which is based on amathematical formula, to control device motors or actuators to follow the sun.Solar Position AlgorithmDescriptionThe National Renewable Energy Laboratory (NREL) Technical ReportNREL/TP-560-34302, revised January 2008, is included with the SolarPositioning Algorithm and sample program. It provides information and codeexamples for a Solar Position Algorithm for Solar Radiation Applications. Theaccuracy that can be achieved by using this algorithm is equal to 0.0003 in theperiod from year -2000 6000. This report is a step-by-step procedure forimplementing an algorithm to calculate the solar zenith and azimuth angles.Rockwell Automation used this report to build a standard logic template that canbe implemented by OEMs to develop tracker equipment.Based on the Micro800 controller platform, the implementation of thealgorithm provides reduced execution time and more precision due to nativesupport of 64-bit floating-point trigonometric math instructions.Data specific to the geographical location must be entered to perform themathematical calculations accurately. The values include the time zone (TZ),longitude, latitude, pressure, elevation, temperature, surface slope, surfaceazimuth rotation, and Delta T (difference between earth rotation time andterrestrial time). Once the local parameters are entered, the program calculatesthe azimuth and zenith angles and the time of sunrise, transit, and sunset for theday of calculation.Rockwell Automation Publication CC-QR005A-EN-P - May 2013
Solar Position Algorithm Connected Components Accelerator Toolkit 5Figure 1 - Position of the Sun Relative to the ObserverSunZenith(Straight UpNorthWestEastSouthθ Zenith Angleφ Azimuth Anglee Elevation AngleThe zenith angle is the angle between the direction of the sun (direction ofinterest) and the zenith (straight up or directly overhead). The user-definedfunction block (UDFB) calculates the zenith angle in degrees and provides thevalue by means of the Out Zenith output. The sun’s elevation, or altitude, is theangle from the horizontal plane and the sun’s central ray or just the complimentof the zenith angle (90 - zenith angle).The azimuth angle is measured clockwise from true north to the point on thehorizon directly below the object. The program calculates the local (fromobserver) azimuth angle and displays it according to two notations: Out AzimuthAstro output provides the astronomer’s azimuth angle,measured westward from south (-180 180 ) Out AzimuthNavi output (0 360 ) denotes the navigator’s azimuthangle, measured eastward from north, which is most often used in solartracking applicationsRockwell Automation Publication CC-QR005A-EN-P - May 2013
6 Solar Position Algorithm Connected Components Accelerator ToolkitSolar Position Algorithm UDFBThe Solar Positioning Algorithm is a user-defined function block (UDFB),named RA SOLAR POSITION ALGRTHM, which can be imported andused in Connected Components Workbench software, version 2.0 or later.The RA SOLAR POSITION ALGRTHM UDFB is capable of calculatingthe position of the sun, relative to the observer, based on a number ofgeographical and environmental parameters at a specific moment in time. It alsocalculates the times of sunrise, transit, and sunset for the day.Rockwell Automation Publication CC-QR005A-EN-P - May 2013
Solar Position Algorithm Connected Components Accelerator Toolkit 7Input and Output ParametersTable 1 - Input ParametersNameData TypeDescriptionCmd CalcBOOLRun calculationCmd SunRTSBOOLCalculate the sunrise, transit, and sunset timesIn YearDINTYear of eventIn MonthDINTMonth of eventIn DayDINTDay of eventIn HoursDINTHour of eventIn MinutesDINTMinute of eventIn SecondsDINTSecond of eventPar TimeZoneLREALObserver time zone (negative west of Greenwich) [hours]Par DeltaTLREALTerrestrial Time (TT) - Universal Time (UT) difference [seconds]Par LongitudeLREALObserver longitude (negative west of Greenwich) [degrees]Par LatitudeLREALObserver latitude (negative south of equator) [degrees]Par ElevationLREALObserver elevation [meters]Par AtmRefractLREALAtmospheric refraction at sunrise and sunset [degrees]Par PressureAvgLREALAnnual average local pressure [millibars]Par TempAvgLREALAnnual average local temperature [degrees Celsius]Par Slope(1)LREALSurface slope (measured from the horizontal plane) [degrees]Par AzmRotation(1)LREALSurface azimuth rotation (measured from south to projection of surfacenormal on horizontal plane, negative west) [degrees](1) Optional - this parameter is needed to calculate the Out Incidence output angle.Table 2 - Output ParametersNameData TypeDescriptionSts ERBOOLError occured during executionErr ValueDINTExecution error, 00001 – One or more input parameters out of range 00002 – Sun is always above or below the horizon for the day ofcalculationOut ZenithLREALTopocentric zenith angle [degrees]Out AzimuthNaviLREALTopocentric navigator's azimuth angle (measured eastward from north)[0 360 ]Out AzimuthAstroLREALTopocentric astronomer's azimuth angle (measured westward fromsouth) [-180 180 ]Out IncidenceLREALIncidence angle for a surface oriented in any direction [degrees]Out SunRiseTimeTIMETime of sunriseOut SunTransitTimeTIMETime of sun transitOut SunSetTimeTIMETime of sunsetRockwell Automation Publication CC-QR005A-EN-P - May 2013
8 Solar Position Algorithm Connected Components Accelerator ToolkitExecution TimeThese are the execution times: Approximately 125 ms for calculation of sunrise, transit, and sunset times Approximately 35 ms for calculation of sun’s positionThe StsER output parameter, when set high, indicates that the instructionencountered an error.Use the Solar Position AlgorithmThe RA SOLAR POSITION ALGRTHM user-defined function block(UDFB) is provided as a Connected Components Workbench export file in the7z format (RA SOLAR POSITION ALGRTHM.7z). The file is in the SolarTracking folder within the Sample Code Modules. This folder also contains anapplication example (SPA M830 24QBB ExampleApplication) thatdemonstrates the use of the UDFBs.Rockwell Automation Publication CC-QR005A-EN-P - May 2013
Solar Position Algorithm Connected Components Accelerator Toolkit 9Import the User-defined Function BlockYou must have a least one UDFB or program already defined in your projectbefore importing a UDFB or program. To import the UDFB, right-click Importand choose Import Exchange File.TIPThe instruction uses several other internal UDFBs. These are imported automaticallyand do not require any action.The algorithm requires several complex mathematical expressions to becalculated at the same time. Standard Micro800 controller memory settingsrestrict extensive memory allocation for temporary variables required by thecalculations. Building a project with the newly imported UDFB results in aninsufficient memory error.Rockwell Automation Publication CC-QR005A-EN-P - May 2013
10 Solar Position Algorithm Connected Components Accelerator ToolkitTo eliminate the error, follow these steps to change the settings of the controller.1. In the Project Organizer, select the controller and press F4.The Property window appears.2. Increase the Memory Size parameter to at least 11,000 KB.The value can change, dependent on the rest of the controller logic.Execute the UDFBThe instruction requires one scan to execute. Because the position of the sun doesnot change quickly, you should execute the instruction only when needed.The instruction is programmed to perform initialization of constants on the firstscan of the controller. For proper operation, place the instruction in a program orrung to be executed unconditionally (that is, with no jumps, IF THEN ELSEstatements, and so forth).For proper initialization, do not condition the EN input when EN/ENO bits areused. See Figure 2. Disabling EN/ENO bits and conditioning the first input ofthe instruction does not prevent proper initialization unless the rung is not beexecuted at all (for example, the Jump instruction was used). See Figure 3.The Cmd Calc input starts the execution of the instruction and calculation ofsun’s position.The combination of Cmd Calc and Cmd SunRTS inputs implies that only thetimes of sunrise, transit, and sunset (RTS) are calculated while the position is not.Because the time needed to calculate the RTS is approximately 200 ms and isneeded only once per day, execute this calculation before the regular operation ofthe solar tracker.Rockwell Automation Publication CC-QR005A-EN-P - May 2013
Solar Position Algorithm Connected Components Accelerator Toolkit 11The RA SOLAR POSITION ALGRTHM instruction can also be used inprogramming languages other than Ladder Logic. Examples of the UDFB calledin Function Block Diagram and Structured Text are shown in Figure 4 andFigure 5, respectively.Figure 2 - Ladder Logic: without ConditioningFigure 3 - Ladder Logic: with ConditioningRockwell Automation Publication CC-QR005A-EN-P - May 2013
12 Solar Position Algorithm Connected Components Accelerator ToolkitFigure 4 - Function Block DiagramFigure 5 - Structured TextRockwell Automation Publication CC-QR005A-EN-P - May 2013
Solar Position Algorithm Connected Components Accelerator Toolkit 13Use RTC in Combination with UDFBOne of the possible sources of date and time data for the instruction can be thereal-time clock (RTC). This functionality in Micro830 and Micro850 controllersis achieved via a plug-in module (catalog number 2080-MEMBAK-RTC).Always install the module in the first plug-in slot. Configure the module in theController Properties dialog box.When the module is properly configured and enabled, you can use theRTC READ instruction to read data from the RTC. Because of the format ofparticular elements of RTC data, the data type is UINT. Convert it to DINT tomatch the RA SOLAR POSITION ALGRTHM input data type.Figure 6 - Using Real-time Clock FunctionalityRockwell Automation Publication CC-QR005A-EN-P - May 2013
14 Solar Position Algorithm Connected Components Accelerator ToolkitValidation and Test ResultsThe user-defined function block (UDFB) was implemented based on the SolarPositioning Algorithm (SPA) published in the National Renewable EnergyLaboratory (NREL) Technical Report NREL/TP-560-34302, revised January2008. NREL refers to the precision of the algorithm as 0.0003 .To verify the correctness of the implementation of the SPA, a simulation wasperformed for a period of 1 year with a sampling period of 30 minutes. Based on17,521 samples gathered, the error of calculation versus results obtained by theNREL Solar Positioning Algorithm Calculator was calculated as follows.AngleAverage AbsoluteError 26098E-05These are the simulation parameters.ParametersValuesStart date and time1/January/2009 00:00:00End date and time31/December/2009 23:30:00Sampling period30 minutesNumber of samples17,521Time zone-7.0 [hours]ΔT67.0 [seconds]Latitude39.742476 [degrees]Longitude-105.1786 [degrees]Elevation1830.14 [meters]Average annual pressure820.0 [millibars]Average annual temperature11.0 [degrees Celsius]Atmospheric refraction0.5667 [degrees]Surface slope30.0 [degrees]Surface azimuth rotation-10.0 [degrees]These results justify the statement that the accuracy of the SPA implementationfor Micro800 controllers is much greater than the mechanical accuracy thatstandard mechanical systems could provide.Rockwell Automation Publication CC-QR005A-EN-P - May 2013
Solar Position Algorithm Connected Components Accelerator Toolkit 15Notes:Rockwell Automation Publication CC-QR005A-EN-P - May 2013
Additional ResourcesThese documents contain additional information concerning related productsfrom Rockwell Automation.ResourceDescriptionIndustrial Automation Wiring and Grounding Guidelines,publication 1770-4.1Provides general guidelines for installing a RockwellAutomation industrial system.Micro830 and Micro850 Programmable Controllers UserManual, publication 2080-UM002Provides a reference guide for Micro800 controllersystems, plug-in modules, and accessories. It also containsprocedures on how to install, wire, and troubleshoot yourcontroller.Connected Components Accelerator Toolkit Building BlockProject Descriptions Quick Reference, publicationCC-QR003Provides descriptions of the available ConnectedComponent Accelerator Toolkit projects.Product Certifications website,Provides declarations of conformity, certificates, and ion/cert certification details.ification/You can view or download publications athttp://www.rockwellautomation.com/literature/. To order paper copies oftechnical documentation, contact your local Allen-Bradley distributor orRockwell Automation sales representative.Allen-Bradley, Rockwell Software, Connected Components Workbench, Micro800, Micro830, Micro850, and RockwellAutomation are trademarks of Rockwell Automation, Inc.Trademarks not belonging to Rockwell Automation are property of their respective companies.Rockwell Otomasyon Ticaret A.Ş., Kar Plaza İş Merkezi E Blok Kat:6 34752 İçerenköy, İstanbul, Tel: 90 (216) 5698400Publication CC-QR005A-EN-P - May 2013Copyright 2013 Rockwell Automation, Inc. All rights reserved. Printed in the U.S.A.
Algorithm with Connected Components Workbench software in a solar tracking application. The algorithm is provided as part of the Connected Components Accelerator Toolkit (CCAT). The CCAT is available on the Connected Components Accelerator Toolkit DVD, publication CC-QR002, or through the Rockwell Automation Software
Solar Milellennium, Solar I 500 I CEC/BLM LLC Trough 3 I Ridgecrest Solar Power Project BLM 250 CEC/BLM 'C·' ' Solar 250 CEO NextEra I Trough -----Abengoa Solar, Inc. I Solar I 250 I CEC Trough -I, II, IV, VIII BLM lvanpah SEGS Solar I 400 I CECJBLM Towe'r ico Solar (Solar 1) BLM Solar I
Mohave/Harper Lake Solar Abengoa Solar Inc, LADWP San Bernardino County 250 MW Solar Trough Project Genesis NextEra Energy Riverside County 250 MW Solar Trough Beacon Solar Energy Project Beacon Solar LLC Kern County 250 MW Solar Trough Solar Millennium Ridgecrest Solar Millenn
4. Solar panel energy rating (i.e. wattage, voltage and amperage). DESIGN OF SYSTEM COMPONENTS Solar Panels 1. Solar Insolation Solar panels receive solar radiation. Solar insolation is the measure of the amount of solar radiation received and is recorded in units of kilowatt-hours per square meter per day (kWh/m2/day). Solar insolation varies .
responding to the solar direction. The solar tracker can be used for several application such as solar cells, solar day-lighting system and solar thermal arrays. The solar tracker is very useful for device that needs more sunlight for higher efficiency such as solar cell. Many of the solar panels had been
There are three types of solar cookers, solar box cookers or oven solar cookers, indirect solar cookers, and Concentrating solar cookers [2-10]. Figure 1 shows different types of solar cookers namely. A common solar box cooker consists of an insulated box with a transparent glass or plastic cover that allows solar radiation to pass through.
Biodiversity Guidance for Solar Developments BRE National Solar Centre, Eds G E Parker and L Greene (2014) Planning Guidance for the Development of Large Scale Ground Mounted Solar PV Systems BRE National Solar Centre Solar Farms: Ten Commitments UK Solar Trade Association Model Ordinances Connecticut Rooftop Solar PV Permitting Guide
Carolina show off the 8 foot solar cooker they constructed as a class project. Solar Fountains Dynamic Demonstrations of Solar Power at Work Solar fountains are fun and easy to build. Using . Building a Solar School Yearly 10th Grade Project Adds Capacity to Midland School's Solar Array Midland School is going solar, one class at a time .
Russell, S. and P. Norvig Artificial Intelligence: A Modern Approach. (Upper Saddle River, NJ: Prentice Hall, c2010) third edition [ISBN 9780132071482 (pbk); 9780136042594 (hbk)]. Russell and Norvig is one of the standard AI textbooks and covers a great deal of material; although you may enjoy reading all of it, you do not need to. The chapters that you should read are identified in the .
