[Porsche-O-Phile]

Trombe walls, stack effect ventilation, etc.

There are numerous types of passive systems that can be used; most of these have been around for decades, if not centuries, but have become "passe" in the modern world of convenience heating/cooling and easy-to-obtain HVAC systems.

I can point you out to a number of good resources on the subject of sustainable design if you're interested, or I'd suggest contacting an architect in your area who specializes in sustainable residential design.