Friday, January 16, 2009

Urban Solar Thermal Power

Place a solar thermal collector on the highest building in a city. Then assemble a distributed array of mirrors on surrounding rooftops. With dual-axis tracking, the mirrors can direct sunlight to the central collector based on two signals: 1) a photosensor that follows the sun and 2) a periodic wireless signal from the collector.

Each distributed mirror is independently managed by a small photovoltaic-powered control system, so there are no wires to run, no infrastructure, no hassle. You simply lease a plot of roof space from your neighbors and grab the economies of scale offered by concentrated solar power. Apply solar-thermal technology at the collector to boil a working fluid and turn a turbine/generator.

CATEGORY: Energy/Business Idea
IDEATION: January 13, 2009.

1 comment:

  1. My friend Jake writes:

    From what I understand, the biggest limitation to collector tower solar plants is the dispersion of the reflected light. That is, the farther the mirror is from the collector, the less effective it is. I haven't been able to pin down specific numbers, but I remember the maximum distance being disappointingly short. Therefore, the density of the mirror field is of utmost importance.

    So, the rooftop model used on a large scale may be limited to the densest of city centers. Perhaps many smaller "plants" could be spread around a city, but I suspect that the baseline cost of the steam turbines/generators would push the price per watt below the cost effective line. It may just be easier to use expensive photovoltaic cells at that price.

    With that said, I apologize for being a Negative Nancy. Steam generators may be cheaper and the effective reflection distance may be greater than I think. I love the idea of turning rooftops into usable space. Just one step closer to the Jetsons.

    Also, a tweak: the mirrors may not need a photosensor or really any kind of feedback loop. A clock and calendar would be the only input the processor would need. This may prevent unnecessary movement on a cloudy day where the mirrors would search in vain for a proper light source.