Passive Solar Design

The building should be elongated on an east-west axis.
The building's south face should receive sunlight between the hours of 9:00 A.M. and 3:00 P.M. (sun time) during the heating season.
Interior spaces requiring the most light and heating and cooling should be along the south face of the building. Less used spaces should be located on the north.
An open floor plan optimizes passive system operation. -- Steel workshop design excells here!
Use shading to prevent summer sun entering the interior.

Sun Angle and overhand calculator (http://solstice.crest.org/staff/ceg/sunangle/index.html)

A heat load analysis of the house should be conducted.
Do not exceed 6 inches of thickness in thermal mass materials.
Do not cover thermal mass floors with wall to wall carpeting; keep as bare as functionally and aesthetically possible.
Use a medium dark color for masonry floors; use light colors for other lightweight walls; thermal mass walls can be any color.
For every square foot of south glass, use 150 pounds of masonry or 4 gallons of water for thermal mass.
Fill the cavities of any concrete block used as thermal storage with concrete.
Use thermal mass at less thickness throughout the living space rather than a concentrated area of thicker mass.
The surface area of mass exposed to direct sunlight should be 9 times the area of the glazing.
Sun tempering is the use of direct gain without added thermal mass. For most homes, multiply the house square footage by 0.08 to determine the amount of south facing glass for sun tempering.