dsc测量比热容.ppt

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1、Newproposedmethodologyforspecificheatcapacitydeterminationofmaterialsforthermalenergystorage(TES)byDSCAbstract1.Introduction2.Materials3.Methodology4.Results5.ConlusionsabstractThisstudypresentsamethodologytodeterminethespecificheatcapacity(Cp)ofmaterialsforthermalenergystorage(TES)byDSC.

2、ThreedifferentDSCmethodsareconsideredtobeappliedinthemethodology,andareexplainedandcomparedinthisstudyinordertoselectthemostproperoneforCpdetermination.Toperformthisstudy,theCpofthreematerialscommonlyusedinsensibleTESsystems,slate,water,andpotassiumnitrate(KNO3),isdetermined.一、introductio

3、nlackoffossilenergeticresourcesitspriceneedtodecreaseCO2emissionsleadtodedevelopnewenergysystemsabletotakeprofitofrenewableenergyandbeenvironmentallyfriendlyandlessexpensiveTESsystemsareapossiblesolutionSolarenergyabundantcleanandeasyaccessible.problem:asthehoursofmaximumenergydemandmatch

4、withthehoursofnosolarirradiationwiththeaimtofillthisexistingenergysupplygap,TESsystemsarepresentedasthesolutiontostoretheenergyanduseitanytimeTEStechnologiessensibleheatstoragetheprocessbywhichtheheatisaccumulatedduetotheincreaseofthematerialtemperaturewithoutexperimentingstructuralchange

5、s,nophasechangelatentheatstoragephasechange,thermochemicalenergymaterialselectionAhighstoragecapacityTherefore,needahighspecificheatcapacity.(1)定义：在程序控制温度下，测量物质与参比物之间的能量差随温度变化关系的一种技术。DSC曲线峰包围的面积正比于热焓的变化可以测定多种热力学和动力学参数，例如比热容、反应热、转变热、相图、反应速率、结晶速率、高聚物结晶度、样品纯度等。该法使用温度范围宽（-175~725℃）、分辨率高、试样用量少

6、。适用于无机物、有机化合物及药物分析。差示扫描量热法（DSC）（DifferentialScanningCalorimetry）采用试样和一标准物质在相同条件下进行扫描，然后量出二者的纵坐标进行计算。要求标准物质在所测温度范围内没有发生物理化学变化，且比热容已知。常用的标准物质是蓝宝石。具体作法是在DSC内先用两个空样品皿，以一定的升温速度作一条基线，然后放入蓝宝石样品在相同条件下作一条DSC曲线，最后在同样条件下作未知试样的DSC曲线，如图threeDSCmethodsforCpmeasurementThedynamicmethodhastraditionallybee

7、nusedtomeasurePCMlatentheatbutalsoforCpmeasurementsapplyinghighheatingratesinthetemperaturerangeofstudyTheareasmethodisbasedontheCpvalue,thus,howmuchheatfluxisneededtoheatupamaterialfortemperatureincrease,andconsistsofconsecutiveisothermalstagesdiffering1℃withnoheat