SF-98-09-3 -- Basic Study of Radiative and Convective Heat Exchange in a Room with Floor Heating PDF

Radiative heat exchange is a dominant factor in a room with a heated floor. Convective heat exchange is also important because it is increased by air circulation caused by natural convection. Surface temperatures inside the room increase when surfaces receive radiative heat flux originating from the heated floor. Since convective heat exchange takes place between the room air and the inside surfaces, it directly affects the room air temperature. Although radiative heat exchange does not influence room air temperature directly, it decreases the temperature difference between inside surfaces. These behaviors determine the wall surface temperatures and the amount of heat flux between the room air and the inside surfaces. This paper presents several basic characteristics of heat transfer on inside surfaces and temperature and velocity distribution in a room with a heated floor. Basic experiments and numerical analysis on radiative and convective heat transfer were carried out. The following conclusions were obtained: (1) a floor heating experiment produces approximately uniform air temperature except near windows where cold drafts lower the air temperature; (2) numerical analysis qualitatively predicts this kind of room air temperature distribution within 1.8°F (1°C); (3) convective heat exchange constitutes approximately half of the total heat exchange based on numerical analysis.

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