A second law based thermodynamic model to assess the human–thermal environment interaction and measure occupant thermal comfort is developed. It is based on the second-law analysis of an open system in which human elements are combined with the environmental variables to form a holistic model of human– environmental interaction. An objective thermal comfort index (OTCI) that combines air temperature, radiant (surface) temperature, relative humidity, metabolic activity, clothing, air velocity, and skin or body temperature is developed to provide an objective measure of thermal comfort. The human thermal responses due to different ambient conditions are obtained using data from an earlier experimental study. The advantage of using an index to quantify thermal comfort is that it can be integrated into an environmental control system to reduce the number of variables that occupants would need to control their personal spaces by providing a smart technology that senses the overall occupant thermal comfort. The OTCI methodology could signifi cantly contribute to the design of occupant-centered energy-effi cient sustainable indoor environments.
entropy, objective thermal comfort index, second law, thermodynamics.
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