PV Gap

Mabel Said:

how much does the shade from rooftop solar panels reduce energy consumption in cooling? (assume 100% covered)?

We Answered:

Found the site listed in the source. It compares different roofing material and the temperature rise resulting. One could imagine that the solar panels would be smooth. The other source goes on to say cooler roofing material can reduce air conditioning costs 10-20%.

Derrick Said:

What Is better for producing a energy for one family large home Windmill or Solar panels?? Also Why?

We Answered:

There's a couple of issues, the first being what you're allowed to have. In many neighborhoods a wind turbine would be out of the question because they make a lot of noise and they sand out visually hence it may violate the neighborhood's deed restrictions. But if you are allowed to have a wind turbine, they are much less expensive then Solar Photo-Voltaic and with a grid tie in, you wouldn't need an expensive battery bank.

The second is what are your energy needs? The majority of the energy used by a household is for hot water, residential heating and or air-conditioning. All three of these could be met with Solar thermal collectors at a fraction of the cost of Solar Photo-Voltaic. The Solar air-conditioning would require an absorption chiller to turn the heat into chilled water for the air-conditioning and would most likely work best with evacuated tube solar thermal collectors. With the exception of evacuated tube, solar thermal collectors are sufficiently low tech that you could build your own collectors. Solar thermal is in fact more efficient than current Photo-Voltaic as the current Photo-Voltaic cells only respond to very specific wavelengths of light. If you meet the majority of your energy needs with inexpensive low tech solar thermal collectors, then you can greatly reduce the size of your Photo-Voltaic system.

I would say that you should try and meet most of your energy needs with Solar Thermal collectors and if your neighborhood allows, have a small wind turbine with a grid tie in for electricity. If you're not allowed to have a wind turbine then a small PV system, again with grid tie in would suffice.