Preparation And Research Of Composite Phase Change Material For Heat Storage Which Build On Clay For Solid Support

Nowadays, energy crisis is a world problem which has to solve. The technology of phase change for heat storage is signality for energy source allocation. However the coefficient of heat conductivity of simplex phase change material for heat storage is low and the material will turn to liquid when it reach to the phase change temperature, the feasibility for practical application is small. So it is necessary to compound it with other material in order to preparation out compound phase change material which performance is good. The research of this compound material has practice meaning.After organic treatment, the modified clay (montorillonite, rectorite and kaolin) is compound with fatty acid (phase change material for heat storage) by hot melt method and solvent evaporation method. The paper use mensuration of coefficient of heat conductivity and the time of heat release to study the feasibility of differ clay as composite phase change material for heat storage bearer and the two preparation methods. At the same time, using the test XRD, IR, TG, DSC to describe it's structure and discuss the mechanism of the compound and heat storage of the compound phase change material for heat storage .The performance of composite phase change material for heat storage's heat storage are same when use the hot melt method and solvent evaporation method. How ever compare with solvent evaporation method hot melt method has many advantages, such as low preparation cost and low pollution to the environment, so hot melt method is main used to experimental investigation.Test result proclaim that the performance of composite phase change material for heat storage is stable when the organic montorillonite and rectorite organic, The composite material will kept solid state when it in the hot environment(10℃~30 ℃ over the melting point of fatty acid),how ever the fatty acid will turn to liquid state in the same environment. At the same time, after cold circulation of heat we can find that the performance of composite phase change material for heat storage the will change if fatty acid compound with organic kaolin, it show that it is hard to compound the composite material with organic kaolin.Form the experiment ,the best conditions can be confirmed: content of the organic clay is 50%,composite time is 30min, composite temperature is 90 °C (stearic acid) , granularity screen mesh -60~+120. The coefficient of heat conductivity of this composite material is 1.86w*m"1#°C"1, far larger than the coefficient of heat conductivity of fatty acid which is O-lSOwm"1*^"1 and larger than demand which is lw'm*1*^"1. the critical heat of the composite is 59.521 J# g~\the T35 is 33min.From XRD traces ,the d of 18—OMT is 2.145nm, the d (Ooi> of 18—MPCM is 2.103nm, from FTIR spectra, the characteristic absorption band of the fatty acid still display independence. From TG, DSC test, we know that because of the burning of stearic acid the loss of weight of composite phase change material for heat storage is 30.85% more than organic clay .It confirm ed that the fatty acid has no chemical change and still consist in the composite phase change material for heat storage in the form of molecular layer.