# Terminology Key terms and concepts used throughout the 3D Design Tool and solar design process. ## Solar Metrics ### TOF (Tilt and Orientation Factor) A ratio comparing solar energy received by a tilted panel versus horizontal mounting. Shows how panel angle and direction affect performance. - **Value range:** 0.0 - 1.2+ - **Interpretation:** Higher values indicate better orientation - **Example:** TOF of 1.05 means 5% more energy than horizontal ### SAV (Solar Access Value) The percentage of available sunlight a site receives compared to an unobstructed location. - **Value range:** 0% - 100% - **Interpretation:** Accounts for shading from trees, buildings, and obstructions - **Example:** SAV of 80% means the site gets 80% of available sun ### TSRF (Total Solar Resource Fraction) Combines solar access (SAV) and tilt/orientation factors (TOF) to show total potential solar energy capture. - **Value range:** 0% - 120%+ - **Interpretation:** Most comprehensive single metric - **Example:** TSRF of 90% means site receives 90% of ideal solar energy - **Formula:** TSRF = SAV × TOF ### Azimuth The compass direction a panel faces, measured in degrees. - **0°** = North - **90°** = East - **180°** = South - **270°** = West - **Optimal (Northern Hemisphere):** 180° (south-facing) - **Optimal (Southern Hemisphere):** 0° (north-facing) ### Tilt The angle of panels relative to horizontal, measured in degrees. - **0°** = Flat/horizontal - **15-30°** = Typical residential - **Latitude° = Optimal** for annual production - **Example:** Location at 40°N latitude → optimal tilt ≈ 40° ## System Configuration ### Panel Wattage The power output rating of a single solar panel in watts (W). - **Common values:** 300W, 350W, 400W, 450W, 500W - **Trend:** Increasing over time due to technology improvements - **Impact:** Higher wattage = fewer panels needed for same system size ### DC/AC Ratio The ratio of panel DC (direct current) capacity to inverter AC (alternating current) capacity. - **Typical range:** 1.1 to 1.5 - **Lower ratio (1.1):** Less clipping, may under-utilize inverter - **Higher ratio (1.4+):** More energy production, some clipping - **Clipping:** When panel production exceeds inverter capacity (energy is lost) - **Optimal:** Usually 1.2-1.3 for residential ### System Losses Total energy losses in the system including wiring, inverter efficiency, soiling, and other factors. - **Typical range:** 14-18% - **Components:** - Inverter efficiency loss: 2-4% - DC wiring loss: 1-2% - AC wiring loss: 0.5-1% - Soiling loss: 2-5% - Shading loss: Variable - Temperature loss: 3-6% - Mismatch loss: 1-2% ### Panel Orientation How panels are physically mounted. - **Portrait (Vertical):** Panels are taller than wide - **Landscape (Horizontal):** Panels are wider than tall - **Impact:** Affects layout, spacing, and available roof space utilization ### Panel Stagger A layout pattern where alternating rows are horizontally offset. - **Benefits:** - Improves coverage on irregular roof shapes - Can increase panel count - Aesthetic appearance - **Drawbacks:** - More complex installation - May increase wiring complexity ## Geometry & Structure ### Baseline The reference edge of a polygon used for calculating roof slope. - The roof slopes away from this edge - Can be rotated using `R` key - Critical for accurate roof modeling ### Slope (Pitch) The angle of a roof surface, measured in degrees from horizontal. - **Also called:** Roof pitch, tilt angle - **Common values:** - 0° = Flat roof - 5-10° = Low slope - 18° (4:12) = Standard residential - 27° (6:12) = Steep residential - 45° = Very steep ### Polygon A 2D shape representing a building roof or structure. - Drawn by clicking points to create outline - Extruded into 3D with height and slope - Can have panels, obstructions, and annotations ### Canopy Mode Converts polygons into open structures with support columns instead of solid roofs. - **Types:** - Corner Columns - Pole Mount - Truss Structure - **Uses:** - Solar carports - Ground mounts - Pergolas ## Data & Analysis ### DSM (Digital Surface Model) 3D elevation data representing the height of surfaces including buildings, trees, and terrain. - **Source:** LiDAR or photogrammetry - **Uses:** - Accurate height modeling - Shadow analysis - Terrain mapping - **Access:** Press `L` to toggle DSM data ### Shadow Analysis Calculation and visualization of how shadows move across the scene throughout the day and year. - **Factors:** - Sun position (varies by time and date) - Object heights - Latitude/longitude - **Uses:** - Optimize panel placement - Identify shading issues - Estimate production losses ### Heatmap Color-coded visualization showing cumulative shadow intensity across surfaces. - **Red areas:** Heavy shading (less solar access) - **Yellow/Orange areas:** Moderate shading - **Green areas:** Minimal shading (good solar access) - **Access:** Press `H` to toggle heatmap ### Solar Production Estimated annual energy output of a solar system. - **Calculated using:** PV Watts API - **Inputs:** - Location (lat/lon) - Panel configuration - System size - Tilt and azimuth - Shading factors - **Output:** Annual kWh ## Spacing & Layout ### Row Spacing Vertical distance between rows of panels, measured in inches. - **Purpose:** Prevents row-to-row shading - **Flat roofs:** 12-36 inches typical - **Sloped roofs:** 0-6 inches (usually flush) - **Ground mounts:** 12-48 inches depending on tilt ### Column Spacing Horizontal distance between columns of panels, measured in inches. - **Purpose:** Accommodates racking system - **Typical:** 0-6 inches - **Impact:** Affects panel density and total system size ### Obstruction Any roof feature that prevents panel placement. - **Common types:** - Vents (plumbing, exhaust) - Chimneys - Skylights - HVAC units - Satellite dishes - **Impact:** - Reduces available space - May cast shadows - Affects production ## Production Metrics ### Annual Output Total estimated energy production over one year. - **Unit:** Kilowatt-hours (kWh) - **Typical residential:** 5,000-20,000 kWh/year - **Factors:** - System size - Location - Panel orientation - Shading ### System Size Total installed capacity of the solar system. - **Unit:** Kilowatts (kW DC) - **Calculation:** Panel count × panel wattage ÷ 1000 - **Example:** 20 panels × 400W = 8.0 kW ### Efficiency (System) Energy production per unit of installed capacity. - **Unit:** kWh/kW annually - **Typical range:** 1,200-1,800 kWh/kW - **Interpretation:** Higher = better performance - **Varies by:** Location, orientation, shading ### Offset Percentage of energy consumption that solar production covers. - **50% offset:** Solar covers half of usage - **100% offset:** Solar covers all usage - **120% offset:** Solar produces more than usage (exports to grid) ## Conversions ### Common Unit Conversions - **1 foot = 0.3048 meters** - **1 meter = 3.281 feet** - **1 inch = 0.0254 meters** - **1 kW = 1,000 watts** - **1 MW = 1,000 kW = 1,000,000 watts** --- **See Also:** [[Shortcuts Reference]] for complete keyboard shortcuts guide.