Talk:Sun-tracking

I would also recommend including content about passive solar tracking, as this eliminates both electronics and motors from the equation, and makes solar tracking possible with relatively basic materials. See the zomeworks tracker for details on this method: http://zomeworks.com/products/pv-trackers. Electronic solar trackers can often provide a 100% increase in photovoltaic efficiency, and passive trackers provide between 45% and 85%, depending on a number of environmental factors, foremost being wind.

However, since they have very few moving parts, and rely on gravity + evaporation to track the sun, they require almost no upkeep. Compared to electronic/motorized trackers, these guys are the epitome of lifetime engineering.

Combo Tracker?
Could you do both, calculate where the sun should approximately be and then use feedback to accurately place it? Catprog 15:16, 28 July 2011 (CEST)

Parabolic dish allows for very simple sun tracking
Instead of the Solar Fire's P32 method, I would use a parabolic dish which will be more powerful in early morning and late afternoon, capturing a lot more area. For 32 kW (peak) the support point would need to be 3 meters above the ground and strong enough for winds as the top edge of the dish would be 6 meters above the ground. Use an equatorial axis that is adjusted once every few days and you only need 1 axis of solar tracking instead of the P32's 5 different adjustments every 10 minutes or so. Physically aim it in the morning at say 9 am, and it remains perfect to within the accuracy of the clock. This assumes equatorial axis that is adjust every week. Receiver "bucket" of water will be 1.5 meters from dish's center support point.

Parabolic Trough for Serious Power
For serious steam (300 kW) parabolic trough is needed. This is better than heliostats because heliostats require 2-axis tracking for every mirror. The drawback is that it requires glass-enclosed light receiver pipes, and parabolic mirrors (curved special-surface aluminum, mirror slats, or aluminized mylar (very light)). The biggest advantage will be that only a timer is need to control altitude, which needs to be only 1/3 as accurate as azimuth axis since the change in angle is only about 50 usable degrees on most days. Since you can't do equatorial axis with trough, the timer may need three potentiometer adjustments (morning start, mid-day peak, and stop point) to be change once every few days in spring and fall (less sensitive in summer and winter). Trough may also be optimal and serve double-duty for brick firing as I mentioned elsewhere on a CEB discussion page. Zawy 16:16, 31 July 2011 (CEST)

Sun concentrator for water heat storage
If living areas are not properly designed, or if more heating for night is needed for living or greenhouse, heating of water provides ideal heat storage. Water storage "tank" would be a plastic-lined hole (insulation not really needed), buried under the attached greenhouse if not the center of the house. A large car-type radiator could be movable to provide heat anywhere. The storage tank can serve as double-duty for water storage. 300 gallons at 120 F (34 kWhr starting from 70 F) are needed to keep a typical R-15 1,000 sq ft house warm overnight, so 3,000 gallons for 10 cloudy days is not overkill (three 4x8 areas, 5 feet deep). Each 100 gallons requires one 4x8 sun collection area to bring it up to temp, so 3,000 gallons is 30 4x8 apertures areas of parabolic trough. 8 feet high is reasonable, so that's 2 rows 60 feet long, covering as much land area as the 1,000 sq ft house it is warming. 100 kW of sun exposure in summer for the steam engine. Zawy 20:57, 1 August 2011 (CEST)

Parabolic trough needs to be parallel to ground
I've seen several DIY parabolic trough designs that are not parallel to the ground. This defeats 2 main reasons for the trough: 1) you don't waste land or get shadows side-to-side and 2) altitude adjustment is much smaller that azimuth adjustment (60 degrees over the course of a day instead of 160). This lessens accuracy requirements. There is waste on the ends from this benefit, so longer troughs are better. Zawy 17:28, 31 July 2011 (CEST)