Embedded water-based surface heating, Part 2: Experimental validation

Artikel i vetenskaplig tidskrift, 2010

The transient operation of an embedded water based floor heating system has been studied by means of a numerical simulation tool. Prior to this study, Caccavelli et al. (1994) experimentally derived reference data for the specific setup. This paper constitutes an attempt to experimentally validate the numerical simulation tool that was recently developed by Karlsson (2010). The thermal response of the system is tested in both long (16 h) and short (30 min) cycle experiments where the water flow alter between on and off. Temperature distribution, within the floor construction, and the heat exchange process are studied throughout the test cycles. The model underestimates the steady state heat exchange from the pipe loop by 16% when boundary conditions and thermal properties according to the reference case are applied. Temperatures at the floor surface are assed with good precision while temperatures at the core of the concrete slab are underestimated by up to 1.5°C. Amplitudes, phase shifts, rise and delay times at different measurement points are simulated with good precision. A sensitivity analysis is performed where material parameters and boundary conditions are analysed. None of the tested parameters can independently explain the observed general trend in temperature deviations between simulations and measurements.