3919

3697

كارشناسي ارشد

تبديل انرژي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1386

چهارده، 108،[II]ص: مصور، جدول، نمودار

ص.ع.به: فارسي و انگليسي

علي اكبر عالم رجبي

محسن نصر اصفهاني

5/3/87

احمد رضا پيشه ور، احمد صداقت

مهندسي مكانيك

ID3697

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

AbstractThe gap between production and consumption of energy is growing and non renewablefossil fuels are discharging and its pollution is growing rapidly Therefore natural resourceslike thermal energy in air water and ground and solar is researched Efficient utilization of these resources can only be done through thermal energy storagesystem and one of the best ways of conserving thermal energy is by using the under groundthermal energy storage system The most economic system of UTES is storage in aquifers Aquifer thermal energy storage In this system two wells are drilled in to permeableunder ground water and injection and withdrawal of cold and hot water is performedthrough these wells Hot water in summer is injected in the hot well and is stored in aquiferfor some days and is withdrawn in winter for heating applications The system which is studied here is composed of a single well of radius R fullypenetrating a confined aquifer of finite vertical extension h Water is injected in to theaquifer at a constant rate Q at temperature Tinj that is warmer than the natural temperatureof the aquifer Tini The continuity and heat transfer equations are developed in cylindricalcoordinate using symmetric formulation The porous medium is assumed to be continuousand its equivalent thermal conductivity and volumetric heat capacity are considered to be afunction of porosity and thermal characteristic of the fluid and solid phases Thelongitudinal and transversal thermal dispersion influence on the effective thermalconductivity The domain is assumed to be homogeneous and isotropic and the verticalcomponent of velocity is equal to zero in all locations i e radial flow Free convectionphenomenon is disregarded and none of the physical properties are dependent ontemperature The target is to achieve the temperature distribution at 60 days after start of injection and30 60 and 90 days after start of withdrawal With numerical solution the thermal equationfor several flow rates and several injection temperatures the ratio of the extracted enthalpy withdrawal stage to the stored enthalpy injection stage is defined as the system thermalefficiency and at the end the system efficiency is displayed for different flow rates anddifferent times of injection and withdrawal It is observed that temperature of injection ofwater does not influence the thermal efficiency but increasing the flow rate and porosityfactor and decreasing the thermal dispersion increase the thermal efficiency In periodicinjection like using solar energy for some times of days thermal efficiency is higher thancontinuous injection and then storage in aquifer

علي اكبر عالم رجبي

محسن نصر اصفهاني

احمد رضا پيشه ور، احمد صداقت