Widespread public acceptance of heating and cooling systems utilizing alternative energy sources is largely dependent on their ability to replace conventional systems with no appreciable loss in comfort or convenience. Research was done to determine why current passive solar heating systems and double-shell solar heating/ground cooling systems do not have performance comparable to conventional systems. This information was then utilized to develop the concept for a new multifunction wall system for application with solar heating and ground cooling. The concept of this system is to expand the use of the structure and enclosure elements of a building to function additionally as: The ductwork for the solar heated or earth cooled air, the heat transfer membrane between the heated or cooled air and the living environment of the building, the heat storage medium (in winter), and the temperature leveling and control medium. All these functions are integrated into a single wall construction using a new concrete block and other supporting components. In addition to developing the concept, several critical components of the system were physically tested and analyzed. This paper presents the research, concept development, testing, and conclusions for this new system, a multifunction wall system for application with solar heating and ground cooling. / M. Arch.