# Wind and electricity scenario controls Both interactive viewers now include wind-speed, generator-wattage, physical generator-diameter and length, and duration controls. The generator diameter and length change a gold 3D envelope inside the elevated wind column. The surrounding column becomes transparent while the overlay is enabled. This envelope is a placement study; it is not a generator product or a promise that a given watt rating fits that volume. Existing GLB downloads retain the original sculpture geometry. Outputs show estimated electrical watts, watt-hours over the selected duration at constant wind, and the power balance after the selected light and sound loads. A curve shows the estimate across wind speeds. The hand wheel is a separate manual motion preview and is excluded from the wind electricity estimate. Pause wind animation pauses the motion and sound preview; it does not change the potential output estimate for the entered wind. ## Model The swept diameter comes from the largest horizontal radius of the selected 3D blade surface; blade height comes from its vertical extent. For these vertical-axis rotors, swept area is diameter times blade height. Openings, appendage porosity, solidity, blade count and creature-specific aerodynamic effects are not individually modeled. All creatures share the user-selected rotor capture coefficient, so this tool must not be used as a tested aerodynamic ranking. Within the entered start and shutdown speeds: `Estimated electrical W = min(generator rated W, max(0, 0.5 × air density × swept area × Cp × conversion efficiency × (wind speed^3 − start speed^3) − fixed operating loss))` Below the assumed start speed or at/above the assumed shutdown speed, estimated output is zero. The cubic subtraction is a deliberately simple startup-ramp assumption; it is not a measured power curve. A larger generator rating raises a capacity ceiling and does not create more energy from the same wind. `Estimated energy Wh = estimated W × entered hours` This duration assumes the exact entered wind speed remains constant. It is not an annual energy forecast or a weather estimate. `Power balance W = estimated electrical W − light demand W − sound demand W` Light receives power first. The wind column's light preview brightens according to how much of its light demand is covered. The low-tone preview uses any remaining power toward the sound demand. Muting browser audio does not change the installation load assumption. A negative balance identifies the additional power that would have to come from storage or another supply; storage is not modeled. ## Initial assumptions - Wind speed: 6 m/s. - Generator rating: 100 W. - Generator envelope: diameter 120 mm, length 140 mm. - Rotor capture coefficient Cp: 0.12. - Generator and conversion efficiency: 75%. - Fixed operating loss: 0.5 W. - Assumed start: 3 m/s; assumed shutdown: 20 m/s. - Air density: 1.225 kg/m³. - Lighting demand: 3 W; sound demand: 2 W. - Duration: 1 hour at constant wind. - Tip-speed ratio for the illustration: 0.7. These are editable design-study assumptions, not tested specifications or recommendations. Generator dimensions affect the displayed envelope only; they do not imply a watt capacity, efficiency, starting torque or speed characteristic. The illustrative rotor speed is tip-speed ratio times wind speed divided by the measured rotor radius, converted to RPM. The animation is slowed when needed to keep the creature shapes readable. That is not a dynamic rotor-speed calculation. The viewer assumes appropriately matched generator voltage, speed and load control; cogging, torque balance, voltage versus RPM, gearbox effects, turbulence, temperature, braking and real efficiency curves are absent. A commercial generator must eventually be selected from its actual data and tested with the rotor. The generator-envelope warning compares its diameter with the approximate 190 mm outer outline of the existing upper wind column. A smaller envelope does not establish clearance for wall thickness, bearings, cabling, fastening, heat removal or maintenance. ## Save and reproduce The **Save estimate CSV** button exports the selected creature, wind, geometry, generator rating and dimensions, duration, efficiency, thresholds, loads, assumptions and estimates. Settings are remembered locally in the browser. Simulation data and source files are included in `source/` for review. Both complete-collection archives include the updated viewers and these notes. ## Background sources The wind power dependence on air density, swept area, wind speed cubed and rotor power coefficient is described in the [U.S. Department of Energy Small Wind Guidebook](https://www.energy.gov/cmei/systems/windexchange/small-wind-guidebook). The distinction between captured rotor power and converted electrical power, and the importance of matching generator loading, are discussed in [this NREL variable-speed turbine study](https://www.nrel.gov/docs/fy00osti/24791.pdf). The scenario defaults and startup model above are original illustrative choices, not creature-blade measurements from either source.