"There is a natural fit on the heating side," said Andy Erbach, associate professor for the energy management program at Elgin (Ill.) Community College, which had a large mobile exhibit trailer on site.
"Radiant panels and hydronics can be tied to solar thermal systems."
then noted, "Regarding the viability of sustainable a/c systems, while conventional split systems and air-to-air heat pumps are becoming more and more efficient, and SEER ratings are rising, I believe that the most energy-efficient methods of cooling a home are some of the oldest, such as shading, ventilation, proper window location, and proper building envelope design.
These passive cooling systems have been used for centuries and are still effective today.
"In the area of mechanically driven, energy-consuming equipment, some of the most practical and efficient residential air conditioning systems today are those that are earth-sourced.
Earth tubes and geothermal heat pumps are both examples of available technology that are used in this area to cool residences."
Regarding residential refrigeration, Erbach
mentioned photovoltaic for 12- to 24-V refrigerators.