John I. Yellott

Yellott published hundreds of articles, papers, and addresses. A selected list of 120 just in solar energy can be found at Passive Solar Journal Vol. 4, No. 3, 1987 pg. 329 et seq., from which the following representative sample is drawn:

Yellott died of a heart attack in Phoenix in 1986, survived by his (second) wife Barbara, a son and a daughter, two stepsons and six grandchildren.

Yellott's early interest, the source of much consulting work, was on the transparency and transmissivity of glass. In 1960s he helped to develop the solar heat gain factor (SHGF) method of calculating the passive thermal role of glass, now the standard method accepted by the American Society of Heating, Refrigerating and Air-Conditioning Engineers. He served as a consultant to major industrial concerns such as Corning Glass, PPG Industries, Libbey-Owen-Ford Glass company, Shatterprufe Glass Company of Port Elizabeth, South Africa; and Pilkington Brothers Glass Company of Great Britain. One of Yellott's clients was Northrup, Inc. whose founder Leonard L. Northrup Jr. was introduced to solar technology by Yellott, and whose company went on to develop some of the first solar air conditioning systems and heliostats, under Yellott's on-going advice.

In June 1958 Yellott founded John Yellott Engineering Laboratories, and the Yellott Solar Energy Laboratory, in Phoenix, Arizona. He became an industrial consultant, with a primary focus on reflective glazing. He served as Headmaster and then Director of Development for Phoenix Country Day School, and taught environmental control systems at the College of Architecture at Arizona State University. As the first Chairman of the ASME Solar Energy Applications Group (later Solar Energy Division) he was in a position of leadership "that was critical to the official 'rediscovery' of solar energy following the 1973 oil crisis". Soon after the oil crisis, Arizona State's College of Architecture instituted a solar program and chose Yellott as its head; he continued to teach there until his retirement at age 70.

After the War Yellott served as Director of Research, Locomotive Development Committee, Bituminous Coal Research from 1945 until 1955. In 1955 at age 47 after having already achieved recognition in steam, coal, gas, and nuclear energy, he switched fields—to passive solar energy. Yellott said the change resulted from "the realization that the entire world, and the United States in particular, was running out of fluid fuels, and that we must find a way to gain economic access to the limitless energy of the sun." In a 1974 interview with Popular Science Magazine Yellott said he anticipated soon "[t]he inexorable forces of economics will bring about the age of solar energy." He organized the 1957 Living with the Sun competition, a seminal event in the history of the solar house.

Yellott embarked on a career in academia at the Stephens Institute of Technology, Hoboken, and at Illinois Institute of Technology, where he was chairman of the Department of Mechanical Engineering from 1940 to 1943 and director of the Institute of Gas Technology from 1943 to 1945. During World War II he was assigned to the Manhattan Project to work on the development of atomic weapons as a consultant to the Metallurgical Laboratory of the University of Chicago.

John Ingle Yellott (October 25, 1908 – December 30, 1986) was an American engineer recognized as a pioneer in passive solar energy, and an inventor with many patents to his credit. In his honor the American Society of Mechanical Engineers (ASME) Solar Division confers a biannual "John I. Yellott Award" which "recognizes ASME members who have demonstrated sustained leadership within the Solar Energy Division, have a reputation for performing high-quality solar energy research and have made significant contributions to solar engineering through education, state or federal government service or in the private sector."

John Ingle Yellott was born in Bel Air, Maryland, the son of the Reverend Dr. John I. (1873-1935) and Mildred Walker Nelson Yellott (1876-1954). He was educated at Bel Air High School and Episcopal High School in Alexandria, Virginia, and then studied Mechanical Engineering at Johns Hopkins University, Baltimore, receiving his M.E. in 1931 and his M.M.E. with distinction in 1933.