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

Electric heating of buildings results in considerable overloads of the dist ribution grid during peak winter periods. One way to alleviate this problem is to store electricity as thermal energy during off-peak hours and to dis charge it during peak hours. In the present study, we examine the thermal b ehavior of two electric heating floor panels containing respectively water and n-octadecane paraffin in a concrete structure. In the first case, off-p eak 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 experimentall y, has been used for parametric studies which led to the choice of dimensio ns and operating characteristics for each panel. The one containing paraffi n is more compact than that with water (134 mm thickness versus 152 me), st ores more energy (2 880 kJ.m(-2) versus 2 415 kJ.m(-2)) and provides more c omfort since the daily temperature fluctuations at its surface are less imp ortant (1.3 degrees C versus 3.8 degrees C). (C) Elsevier, Paris.