Thermal analysis of electric heating floor panels with daily heat storage.

Electric heating of buildings results in considerable overloads of the distribution grid during peak winter periods. One way to alleviate this problem is to store electricity as thermal energy during off-peak hours and to discharge it during peak hours. In the present study, we examine the thermal behavior of two electric heating floor panels containing respectively water and n-octadecane paraffin in a concrete structure. In the first case, off-peak electricity is stored as sensible heat in the water and concrete, while in the second case it is primarily stored as latent heat in the paraffin. A transient one-dimensional model, validated analytically and experimentally, has been used for parametric studies which led to the choice of dimensions and operating characteristics for each panel. The one containing paraffin is more compact than that with water (134 mm thickness versus 152 me), stores more energy (2 880 kJ.m(-2) versus 2 415 kJ.m(-2)) and provides more comfort since the daily temperature fluctuations at its surface are less important (1.3 degrees C versus 3.8 degrees C). (C) Elsevier, Paris.