Radiant Floor Heating System

Abstract

The radiant floor heating system controls indoor air temperature by heat transfer from heated surface to indoor air, after the heat has been applied into a floor structure mass by using hot water heating coil buried under the floor. In this case, hot water is provided by a boiler, then, conveyed to indoor floor heating coil through pipe network. The radiant floor heating system can operate transmitting power quietly and efficiently with no noise at low costs of the initial investment and with low maintenance. However, since hot water heating coil is buried under the floor, the system has a defect that it has large thermal inertia by heavy heat capacitance of the floor structure mass. In addition, response characteristics with long time delay will be caused due to certain amount of time needed to heat up the structure mass(Ahn, 2010). Thus, saving energy and maintaining comfortable indoor thermal environment would be possible only if a proper control method is applied into the system, considering its thermal inertia. This chapter introduces system features and mathematical background of radiant floor heating system. Especially, it covers theoretical background of analysis on heat transfer characteristics in pipes and indoor heat flow characteristics to help understand dynamic characteristics of energy in the system. In addition, explanation is given on types and characteristics of automatic thermostatic valves in the system that supplies hot water with on-off or proportional control, and more information is demonstrated on heat flow characteristics and heating performance of the radiant floor heating system in applying various kinds of control systems to comfort indoor heat and save energy.