David Nelson Crosthwait Jr.
May 27, 1898 - February 25, 1976
Engineer, Inventor and Writer

David Crosthwait was an electrical and mechanical engineer and one of the leaders in the United States in the field of heat transfer, ventilation and air conditioning. His achievements include the receipt of 39 U.S. patents and 80 foreign patents for his inventions. Mr. Crosthwait also designed the heating systems for Radio City Music Hall and Rockefeller Center in New York City and authored a heating and cooling manual that detailed standards and codes.

Crosthwait received his B.S. degree from Purdue University in 1913, then went on to get a Masters of Engineering. He served as Director of Research Laboratories for C.A. Dunham and Co. from 1925-1930, then consulted for the company until 1971. Beginning in 1969, Crosthwait taught steam heating theory and control systems at Purdue University. He received an honorary doctorate from Purdue in 1975.

During his time with C.A. Dunham and Co., Crosthwait held many positions, including director of research. While at Dunham, he conducted research in several areas, including heat transfer and steam transport. His work led to many innovations in HVAC devices and technology and held more than 30 U.S. patents. Crosthwait designed HVAC systems; the heating system at Radio City Music Hall in New York City is perhaps the best-known example of his work.

Besides research, product development, and HVAC system design, Crosthwait also advanced his field by writing articles and revising sections of several editions of American Society of Heating and Ventilation Engineers Guide. His accomplishments were recognized by many in his field. He won a medal from the National Technological Association in the 1930s and was made a fellow of the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) in 1971—the first African American to received the honor.

Crosthwait officially retired from Dunham in 1969 after serving as an advisor since 1930. He died on February 25, 1976.