Passive solar design incorporates interaction with the natural phenomenon occurring around us all the time.
Tapping into that self perpetuating force is the smartest way to design a home.
The convection engine draws the cool air through the earth in cooling tubes made of a conductive material like stainless steel.
The hotter the temperature is in the front of the building, the more cool air is drawn through the cooling tubes and the cooler the back of the building becomes.
In winter it is the opposite: the sun shines in through the North facing windows (southern hemisphere) and warms the inside.
So electricity is not needed to run heaters or air conditioners and this means that more power is available for household appliances and other living requirements.