ObjectiveThe temperature variation characteristics of electric heating engineered wood flooring (EHEWF) with different electrothermal layer positions and different structures were investigated in this study, which provides theoretical reference for electrothermal performance and structure optimization of EHEWF.
MethodCarbon fiber paper was used as heating element to manufactured EHEWF by hot pressing method. The time-temperature effect, temperature unevenness, electric-to-radiant power transfer efficiency and surface grid temperature were investigated and analyzed after heating, also simulated the two-dimensional and three-dimensional distribution of surface temperature. The front and back surface temperature rise law of different structure EHEWF were explored and fitted power-function equation of time-temperature curves.
ResultThe results showed that the surface temperature increased with the increase of conductive time, and finally stabilized. After the power was cut off, the temperature began to decrease rapidly until it was in equilibrium with the ambient temperature. As the position of electrothermal layer moved down, the surface temperature decreased after heating stabilized, the electric-to-radiant power transfer efficiency was also reduced accordingly. When the power density was respectively 200, 300, 400 and 500 W/m2, the surface temperature of electrothermal layer locating near surface layer was 17.2%, 21.8%, 24.8% and 26.8% higher than the bottom layer. With the increase of power density, the temperature unevenness and electric-to-radiant power transfer efficiency also increased, the electric-to-radiant power transfer efficiency of electrothermal layer locating near surface layer was 95.6% as power density 500 W/m2. Two-dimensional and three-dimensional simulation showed that the overall trend of surface temperature distribution was middle higher than periphery. The temperature trend was especially prominent for electrothermal layer locating surface layer and there was a phenomenon of heat accumulation. The front surface temperature of different structural EHEWF increased with the increase of the load time. The thicker the back surface wood was, the higher the front surface temperature was, and the lower the back temperature was. The fitting equation showed that the time-temperature change was power function, and coefficient of determination was up to 0.999 9.
ConclusionThe electrothermal layer location and floor structure have significant effects on the surface temperature and electric-to-radiant power transfer efficiency. When the electrothermal layer is located near the surface layer, it is more beneficial to improve the electrothermal performance.