Study On Thermal Properties Of Solar Thermal Energy Storage Materials

At present,the energy demand is increasing,and the replacement of traditional energy by the new energy is extremely urgent,And the development of solar thermal power generation alleviates energy crisis,Therefore,the technology of solar thermal power generation has attracted worldwide attention and developed in recent years.To reduce generation cost,and improve the efficiency of solar power generation and the stability and continuity of solar thermal power generation system,need to add heat storage device,And then the system can continue to meet the power generation needs without the solar radiation energy.If the heat storage problem is solved,then thermal power generation will play a big role in energy replenishment,And heat storage materials are expensive,so it is urgent to study cheap and efficient materials.This paper analyzes the feasibility of coal cinder as solar heat storage material,We've done some theoretical and experimental research,And it provides experimental basis and theoretical basis for selection and performance improvement of thermal storage materials.Firstly,the physicochemical characteristics of coal slag in wenzhou power plant and yangzhou power plant were analyzed by scanning electron microscope(SEM)and laser particle size analyzer.To explore the heat and thermal conductivity of coal slag in two power plants of wenzhou power plant and yangzhou power plant as heat storage materials,And we tested the thermal conductivity and specific heat capacity of the coal slag by using the thermal conductivity and differential scanning calorimeter(DSC).The results show that,the specific heat capacity of coal slag in wenzhou power plant is 1.13 k J/(kg· K),and the thermal conductivity is 0.18 W/(m·K).The specific heat capacity of coal slag in yangzhou power plant is 0.88 k J/(kg·K),and the thermal conductivity is 0.21 W/(m·K),And using ANSYS for numerical simulation,We get the cinder as heat storage material in the distribution regularity of the temperature of the heat storage tank.Secondly,iron powder is added to the cinder(the quality ratio of cinder and iron powder is 9:1),and the modified coal slag is made,Study of its thermal performance,improved coal cinder as thermal conductivity,heat capacity of heat storage material performance.The results show that,the specific heat capacity of coal slag in wenzhou power plant was 13.58 k J/(kg· K),and the thermal conductivity was 3.76 W/(m· K).The specific heat capacity of coal slag in yangzhou power plant was 13.35 k J/(kg· K),and the thermal conductivity was 3.80 W/(m· K).Finally change coal cinder and iron powder mass ratio and stir into the mass fraction of cement,test heat storage and thermal conductivity of heat storage materials.The results show that,the quality ratio of coal slag and iron powder is 5:5,and the thermal conductivity is too strong,which is not conducive to the process of heat storage.When the content of cement is 0.03 g,the heat storage capacity is limited,which is not conducive to the process of heat storage.So,by experiments we can see: When the sample quality is 1g,wenzhou power plant and yangzhou power plant coal cinder in the quality of coal cinder and iron powder ratio of 6:4,the cement content as binder is 0.03 g,coal cinder has the best thermal performance,the most conducive to regenerative process.