John I. Yellott

John Ingle Yellott (October 25, 1908, Bel Air, MD — December 30, 1986, Phoenix, AZ) was a mechanical engineer whose career bridged heavy industry, nuclear research, and solar energy. He earned his ME from Johns Hopkins University in 1931 and his MME with distinction in 1933.

Early career

Yellott chaired the mechanical engineering department at the Illinois Institute of Technology from 1940 to 1943 and served as director of the Institute of Gas Technology. During World War II he worked as a consultant on the Manhattan Project.

Solar energy leadership

In 1954 Yellott co-founded the Association for Applied Solar Energy (AFASE) in Phoenix, Arizona, which later became the American Solar Energy Society. AFASE was one of the first organizations dedicated to promoting solar energy applications.

Yellott founded John Yellott Engineering Laboratories in 1958 and joined the faculty at Arizona State University’s College of Architecture, where he trained a generation of architects in solar design principles. He provided the property, instrumentation, and engineering expertise for Harold Hay‘s 1967 Phoenix Skytherm prototype, a key demonstration of roof-pond passive cooling and heating.

Technical contributions

Yellott developed the ASHRAE Solar Heat Gain Factor method, which became the industry standard for calculating solar heat loads on buildings. He also patented film-type solar water heaters and transparent pool covers, practical innovations that moved solar technology into everyday use.

Recognition

Yellott was an inaugural inductee of the Solar Hall of Fame in 1976. He held a Member of the Order of the British Empire (MBE) and received an honorary doctorate from Arizona State University in 1985. His papers are held at the American Heritage Center, University of Wyoming.

Full article: John I. Yellott

See also

• American Solar Energy Society
• Skytherm
• Harold Hay