Numerical simulation and study of thermal characteristics of a lightweight floor heating system

Abstract

The use of underfloor heating systems is an effective way to achieve thermal comfort for users in energy-efficient buildings. There are two kinds of such systems: traditional and dry-assembled. The first type is researched more deeply than the second one. The paper presents theoretical studies of the thermotechnical parameters of a water underfloor dry-assembled heating system. The design of the underfloor dry-assembled heating system, considered in the work, consists of a heat insulation (expanded polystyrene), on which the pipes of the heating system are located, in contact with an aluminum heat distribution plate. The system is covered with floor finishing. The calculation for a stationary operating mode of the floor heating system was carried out on the basis of a system of equations for momentum and energy. The model was validated using the results of experimental studies. The calculation results cause some overestimation of the experimental data, possibly, beecause of deviations in thermotechnical characteristics of materials. But the simulation model correctly estimates the behaviour of the system at change of its parameters. The paper concludes that this configuration of the underfloor heating system can be used in heating systems for residential and non-residential premises. The aluminum heat distribution plate significantly affects the heat transfer processes in the system. Due to the plate, the heat flux is made uniform in the plane of the floor surface, which has a positive effect on heat distribution and reduces thermal tension in the finish coating. The use of ceramic tiles increases the overall heat exchange efficiency of the system with the room air. An increase in the thickness of the expanded polystyrene board increases the value of the heat flux from the surface of the heated floor. An increase in the flow rate and temperature of the heat carrier also cause an increase in the density of heat flux from the floor surface.