Measuring wall samples

To validate the simulation results, we built up a testing site for wall samples of the size 50 cm x 50 cm (Fig. 5). The wall sample is pressed between two copper plates, which can be heated and cooled independently.

This allows various temperature profiles as input on the surface of the wall samples. By measuring the resulting heat flux and the temperatures in several layers of the sample you can determine the thermal performance of the walls (see Fig. 5). One method is to put a constant heat flux on both sides of the sample and measure the resulting temperature in the middle of the sample. Here you can see the linear temperature increase below (and above) the melting range and how the rise of the temperature is slowed down near the melting point. In this case, the comfort temperature (below 27°C) could be hold 6 hours longer than with the reference material (dotted line).

This measurement can be used to determine the shape of the enthalpy function of the used material as a function of temperature, which is an important input for the simula­tion. This results are also useful in optimising the structure of multilayer constructions with PCMs.