ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
THERMAL ENERGY STORAGE SYSTEM BY MEANS OF PHASE CHANGE MATERIAL-Na2HP04·12H20
要約
The characteristics and potential of Na2HP04·12H20 as a thermal energy storage medium in a heat of-fusion mode have been studied in an annular double pipe heat exchanger. To avoid third phase formation (Na2HP04·7H20), the optimum physicochemical properties for recycling was found to be 37-38 wt. % of Na2HP04 instead of the stoichicometric 39.6 wt. %. Heat transfer properties of the phase change material during heating cycle can be characterized by the conduction for the first stage
and the convection in the latter stage. The rate
of heat storage and heat removal were found to be
in the range of 7.53×105 J/hr and 4.2×105 J/hr, respectively. Also the average overall heat transfer coefficient during heating cycle was found to vary with the liquid flow rate and inlet temperature from 1.95×106 to 6.86×106 W/K m2.
The melt thickness of Na2HP04·12H2O in the thermal energy storage is correlated in terms of
Fourier, Stefan and Reynolds numbers.