Hatsopoulos was born in Athens, Greece in 1927 and is related to[how?] the former rector of the Athens Polytechnic School, Nicolas Kitsikis. He attended Athens Polytechnic before entering MIT, where received his Bachelor and Master of Science (1950), Mechanical Engineer (1954), and Doctorate of Science (1956).
In 1965, he and Joseph Keenan published their textbook Principles of General Thermodynamics, which restates the second law of thermodynamics in terms of the existence of stable equilibrium states. Their formulation of the second law of thermodynamics states that:
|“||When an isolated system performs a process after the removal of a series of internal constraints, it will reach a unique state of equilibrium: this state of equilibrium is independent of the order in which the constraints are removed.||”|
The Hatsopoulos-Keenan statement of the Second Law entails the Clausius, Kelvin-Planck, and Carathéodory statements of the Second Law, and has provided a basis to extend the traditional definition of entropy to the non-equilibrium domain.
In 1976, Hatsopoulos also contributed to a formulation of a unified theory of mechanics and thermodynamics, arguably a precursor of the emerging field of quantum thermodynamics.
While at MIT, Hatsopoulos was head of the Engineering Division of Matrad Corporation (New York). Matrad Corporation and MIT financially supported his doctoral thesis, The Thermo-Electron Engine. Matrad corporation was owned by the family of Peter M. Nomikos, a Harvard Business School graduate. In 1956, Nomikos co-founded with Hatsopoulos the Thermo Electron Corporation. Thermo Electron became a major provider of analytical instruments and services for a variety of domains under the development of George Hatsopoulos, John Hatsopoulos, and Arvin Smith. In 1965, George Hatsopoulos was president of the Thermo Electron Engineering Corporation and Senior Lecturer in Mechanical Engineering at M.I.T..
In 1996, Hatsopoulos won the John Fritz Medal, which is the highest American award in the engineering profession and presented each year for scientific or industrial achievement in any field of pure or applied science. In 1997 he was awarded the 3rd Annual Heinz Award in Technology, the Economy and Employment. Mr. Hatsopoulos is also a recipient of The International Center in New York's Award of Excellence. In 2011, along with Arvin Smith and John Hatsopoulos, he was awarded the 2011 Pittcon Heritage Award from the Chemical Heritage Foundation.