The dehydration kinetics of phase change material KAl(SO4)2•12H2O was studied under non-isothermal conditions and the Kissinger’s method was applied to analyze the TG and DSC data in order to calculation of activation energies and pre-exponential factors for different heating rates. It was concluded that dehydration of KAl(SO4)2•12H2O occurred in three steps. The activation energies and pre-exponential factors were calculated as 95.9 kJ/mol and 1.95×1010min-1 for step I, 128.8kJ/mol and 3.67×1012 min-1 for step II, 159.6kJ/mol and1.92×1013min-1 for step III, respectively. In addition, various materials have been tested to prevent the KAl(SO4)2•12H2O supercooling.

The purpose of this article is to study the impacts of environment on the economic growth of Xi’an. Based on the relevant data from 2000 to 2007, We extended Solow model for calculating the contribution rate of capital, labor and environmental indicators to economic growth. We get the environmental indicators of Xi’an is 43.46% , so it is very important to protect environment. We suggest that emissions-trading system and the deposit repayment system are better ways for Xi’an to solve the environmental problems.

The daily collected heat energy of solar collector in solar water heating system is calculated by the modeling of solar collector and stratified tank, and the result is verified by experiments. Through analysis of the calculation results, the simplified formula for calculating the daily collected heat energy is given. Using this simplified formula, the daily collected heat energy under different flow rates is calculated. The result shows that the daily collected heat energy of solar collector running in solar water heating system tends to stable when the flow rate above 0.005kg/(m2.s).