Salt Lake Solar Ignite
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20-Oct-2014 -
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Transcript of Salt Lake Solar Ignite
Solar Energy Resources
Kevin Bell SLC
Bert Granberg AGRC
Modeling Salt Lake City’s
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Project Goals
• Quantify the Solar Energy Resources at Relevant Scales– City held properties– City-wide– Residential & business properties
• Make results accessible to all
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What’s important
• #1 Solar Radiation on Existing Surfaces
– Flush mount ‘active’ solar systems• Heating • PV electrical generation
– Passive heating/cooling analysis• Tree placement• Heat island effect analysis
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What’s important• #2 Sunlit Hours for Existing Surfaces
– Angled rack mount ‘active’ solar• Heating • PV electrical generation
– Passive uses• H20 planning?
• Gardening?
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Project Requirements
• Digital model of existing terrain and surfaces– LiDAR digital terrain model of study area
• Mathematical model of the Sun’s path– Nat’l Renewable Energy Labs (NREL)
• Integrating Platform– ESRI ArcGIS
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LiDAR = Light Detecting And Ranging • Pulsed laser transmission
• Optical sensor
• Like GPS & Radar, uses time as a surrogate for space to measure distance from a known location
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Using LiDAR to gather terrain data
1. Mount LiDAR sensor on airplane
2. Synchronize LiDAR sensor with high-precision GPS equipment (to get instantaneous geographic position of sensor)
3. Measure vertical distance from plane to surface features (get M for each X,Y)
4. Derive large set of elevation points with 3D geographic coordinates
• Usually 1-2 meters spacing of measurements
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4212
4220
Raster Terrain Model• Concept: graph paper model of an area• Each cell in the array carries and elevation value
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Raster Terrain Model• in GIS, colored by height value
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Raster Terrain Model• in GIS• extruded by height• colored by height value
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Solar ModelingAnimation
Salt Lake Library
March 21
8:00 AM
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Solar ModelingAnimation
Salt Lake Library
March 21
9:00 AM
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Solar ModelingAnimation
Salt Lake Library
March 21
10:00 AM
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Solar ModelingAnimation
Salt Lake Library
March 21
11:00 AM
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Solar ModelingAnimation
Salt Lake Library
March 21
12:00 PM
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Solar ModelingAnimation
Salt Lake Library
March 21
1:00 PM
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Solar ModelingAnimation
Salt Lake Library
March 21
2:00 PM
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Solar ModelingAnimation
Salt Lake Library
March 21
3:00 PM
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Solar ModelingAnimation
Salt Lake Library
March 21
4:00 PM
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Solar ModelingAnimation
Salt Lake Library
March 21
5:00 PM
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Solar ModelingAnimation
Salt Lake Library
March 21
6:00 PM
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Solar ModelingAnimation
Salt Lake Library
March 21
7:00 PM
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Solar Radiation Calculation
ΣFor given dates/times
- Is Surface Sunlit?
- Factor in relationship between Terrain Slope & Sun Position
optimal instantaneous angle = 90 degrees optimal fixed angle = latitude (~ 40 degrees in SLC)
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192
4.5
237
7.2
Completed Raster Model, each cell carries monthly averages
• Sunlit hours • Watt hours
400 million cells x 24 data values10 billion data values
+ implied x,y coords
40000
10000
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Solar Modeling:
• Huge Computational Costs at 1 meter
• Divide and Conquer Approach
• How big a tile to process in isolation?
• How large a buffer to process around the tile
• Look at neighboring tile heights for tall shadow casters
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Divide and Conquer Tiles•Red larger buffers•Yellow medium buffers•Blue smaller buffers
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Raster-based Solar Radiation Results Map Web Service (For Mixed Use Neighborhood)
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Performance Issues
• Raster Datasets are Sequentially Stored data structures– Line scans are fast (rendering)
– Full dataset analysis/summaries are fast (citywide)
– Neighborhood (spatial) queries are slooooow
• And we have 24 of them to deal with– Two measures x 12 months
• Solution….
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Point-based output sample
July Sunlit Duration,Salt Lake Library Building.
Neighborhood Query Performance Solution:
Store all 24 raster values for a given raster cell in a separate vector based data structure as a simple point feature
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Solar Radiation Results Spatial Query Web Service (Aggregated to point shapefile)
• Map image service (based on raster output)
• Spatial Query Web services (JSON, based on vector pts)
input: polygon x,y coordinates
production threshold outputs:
monthly sunlit hours (Duration)monthly watt hours (Radiation)area above production threshold
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Turn Web Services Over to Web Designers
Map Services
Spatial QueryWeb Services
Web App