Lightweight floor heating systems consist of a plastic tube connected to a heat distribution aluminium plate and are used in wooden floor constructions. The thermal properties of lightweight floor heating systems cannot be described accurately. The reason is a very complex interaction of convection, radiation and conduction of the heat transfer between pipe and surrounding materials. The European Standard for floor heating, EN1264, does not cover lightweight systems, while the supplemental Nordtest Method VVS127 is aimed at lightweight systems. The thermal properties can be found using tabulated values or experiments. Neither includes dynamic properties. This article describes a method to find steady-state and dynamical thermal properties in an experimental setup based on finding a characteristic thermal resistance between pipe and heat transfer plate, which can be directly implemented in a numerical simulation model. It has been shown that the method is accurate with an error on the heat fluxes of less than 5% for different supply temperatures. An error of around 5% is also recorded when comparing measurements to calculated heat flows using the Nordtest VVS 127 method based on the experimental setup presented here. Consequently, the test setup can also be used to for tests based on Nordtest VVS 127. The advantage of using the method developed here is that it can be used directly for building energy simulations, while the drawback is the need to build a test setup to find the contact resistance. However, if measurements are performed for several types of lightweight floor heating, this method will become more general.
|Journal||International Journal of Low Energy and Sustainable Buildings|
|Publication status||Published - 2005|