Consider a person wearing sweatpants and a sweatshirt sitting reading a book in the centre of a cubic room that is always maintained at a 20C air temperature. During the winter months, the temperature of all the surfaces (floor, ceiling and walls, no windows) is 17C, while in the summer months the temperature of the surfaces is 23C. a) To what temperature should the air be heated during the winter months to achieve the same operative temperature (Top) in the winter as there is in the summer?

a. To what temperature should the air be heated during the winter months to achieve the same operative temperature (Top) in the winter as there is in the summer?

b. A large floor-to-ceiling, wall-to-wall window replaces one of the walls. In the winter, the interior surface temperature of the window is 9C. To what temperature must the air be heated to maintain an operative temperature of 20C?