UCEEB laboratories (University Centre for Energy Efficient Buildings) at Czech Technical University in Prague just completed the first stage of measurements from its investigation on efficiency, energy consumption and indoor environment quality of heat distribution produced by various heating systems.

This first stage of the study focused on the efficiency of heat distribution exhibited by individual heating systems and the homogeneity of the temperature field they produce.

Temperature difference

It is evident from the structure of the temperature field (in a steady state) that convections heaters produce an important thermal stratification, even in a so-called nearly zero-energy building (the set building quality for the study). In spite of the high performance thermal insulation, the temperature difference goes up to 3ºC (the coldest values reached near the floor).

Those results contrast with the ones obtained for radiant underfloor heating, where the temperature difference reach a maximum of 0.5ºC, providing a much higher homogeneity of the temperature field, both vertically and horizontally.

Temperature graph

Those data were translated in terms of personal comfort, comparing the temperature difference in between head and ankle for a sited and standing person for each type of heating system. From the graph, it clearly appears that the optimum comfort is reached with large-surface radiant systems, i.e. underfloor and ceiling heating. The temperature distribution is becoming less even as we move to the right of the graph where ceiling and wall radiant panels are shown. At the far right end, the temperature distribution is maximum for heating sources based on hot air convection.

Testing will continue with the following stages of the investigation, in which a test mannequin which fully simulates the conditions for the feeling of comfort will be used to compare the energy requirements of the different heating systems for the maintenance of the comfort conditions.