Mathematics question: estimation of shadow around buildings

[Gunnar Wegner]

Hello group,

let's say I want to locate PV panels on the ground, next to a building. The
roof is not an option. Putting the modules south of the building is also
not possible.

Is there a quick way to estimate the distance I'll have to keep to the
building (given its three dimensions and position on the globe) in order to
prevent my modules from being shaded throughout the year? Has anybody
modelled this kind of problem in a CAD or GIS software?

Thank you,

Gunnar :)
--

[Anthony Matonak]

Gunnar Wegner wrote:
> Is there a quick way to estimate the distance I'll have to keep to the
> building (given its three dimensions and position on the globe) in order to
> prevent my modules from being shaded throughout the year? Has anybody
> modelled this kind of problem in a CAD or GIS software?

The process you're talking about is called a solar site survey.
One method to do this is to obtain a sun chart for your location,
available at http://solardat.uoregon.edu/SunChartProgram.html

Then use an inclinometer and compass to map the horizon and draw
it on that chart for a particular spot you are thinking of placing
the panels. This will show when that spot will be in shadow at any
time during the year.

This is a webpage describing the process.
http://www.builditsolar.com/SiteSurvey/site_survey.htm

Another method is to use a "solar pathfinder", basically a tool
that lets you trace the horizon by reflection all in a couple
of minutes rather than fooling around with inclinometers. It's
more expensive but faster. You might be able to rent one.

http://www.solarpathfinder.com/homepower.html

Anthony