Inventor of the “the solar envelope” concept, Ralph Lewis Knowles died in Cleveland on August 23, 2024. He was 95 years old. News of his passing was shared by the USC School of Architecture.
Knowles was born on December 9, 1928 in Cleveland, Ohio, and served in the U.S. Navy after high school from 1946–1948 before completing his Bachelor’s of Architecture at North Carolina State University in 1954 and a Master’s of Architecture at MIT in 1959. After graduating, Knowles felt confined to traditional standards of office work, so he sought a career in academia instead to pursue a more creative trajectory. He spent two years teaching at Auburn University, but found his research was pulling him elsewhere.
In 1962, he applied for a Graham Foundation grant to support his research hypothesis regarding nature’s impact on built structures; he collaborated with renowned architects and educators including Pierre Koenig, Konrad Wachsmann, and Karen M. Kensek to form the Natural Forces Laboratory at USC. He and his wife Mary E. R. Knowles moved to Los Angeles in 1963 so he could continue his research. There, he taught at the USC School of Architecture for over 40 years, and was the Dean from 1973–1975.
Though Knowles became a leading figure during his time at USC, his career lasted for decades following. He produced several works that cemented his place in the field, wrote seven books, and numerous articles and manuals that spread his enthusiasm for passive solar architecture—a key component in contemporary sustainable design initiatives. His work was acknowledged by the AIA Medal for Research and through his Fellowship award and honor as a “Passive Solar Pioneer” by the American Solar Energy Society.
After his retirement, he continued to play an active role as an advisor and research consultant at USC. The school recognized his long-term efforts and innovative thinking having influenced city planning, and design all the while maintaining a conscious approach considering the natural environment, and continue to consider him, “Professor Emeritus, Distinguished.”
