Recent interest in passive solar design has led to numerous analytic methods for including energy concerns in design decisions. These methods characteristically address specific, existing problems or classes of problems. In contrast, this project investigated the incorporation of passive solar issues in design methodology by addressing fundamental concepts of general problem solving. A methodological structure which provides flexible modeling and simulation capability was constructed through the use of various notations -- english, math and Iverson notation (APL). English and math were used in the text of the thesis to communicate theory to the reader. Two APL workspaces, "THERM" and "THERM2," were created to communicate with a computer; and hence, enable the application of the methodological structure to real, complex problems. / M. Arch.