In effect the Passive Annual Heat Storage System is geothermal. It collects heat in the ground in summer and uses it in winter but it has no moving parts. It will work fine anywhere the summer temperatures are 70 degrees or higher. My house is a modified version and dose use solar but the system doesn't need sun.
I think Elliot Coleman's book is good for learning about winter growing.
The Winter Harvest Handbook: Year Round Vegetable Production Using Deep-Organic Techniques and Unheated Greenhouses
Apr 15, 2009