Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Heat and Fluid Flow Analysis in a Channel Partially Filled With Permeable Isotropic Porous Layer(Izmir Institute of Technology, 2012) Uçar, Eren; Mobedi, MoghtadaA theoretical study is performed on heat and fluid flow in a parallel plate channel completely and partially filled with porous medium. An asymmetric heat flux is imposed onto the boundary conditions of the channel fully filled with porous media. However, a symmetrical heat flux is applied to the channel partially filled with porous medium. Dimensional analysis is performed on three parallel plates having different permeability and effective thermal conductivity values. The dimensionless analysis is performed for parallel plates with different values of Da and thermal conductivity ratio. Darcy-Brinkman model is used to investigate the velocity distribution in porous media. The dimensional and dimensionless energy equation and appropriate boundary conditions are written for the analyzed channels. The dimensional equations of motion and heat are solved by numerical methods, while the dimensionless form of those equations are analytically solved to obtain analytical expressions for the velocity and temperature fields in the channel. The dimensional temperature and velocity profiles, obtained by numerical methods, are compared with the analytical expressions of dimensionless temperature and velocity profiles and good agreement between the results were observed. For both fully filled asymmetric heated channel and partially filled symmetrical heated channel, it is observed that the traditional temperature difference (difference between surface and mean temperatures) is not proper to be used in the individual heat transfer coefficient since heat transfer coefficient approaches to infinity and changes sign without changing of heat transfer direction. Hence, a proper temperature difference is required to be defined.Master Thesis A Study on Combination of Electrical Heater, Exhaust Air Heat Recovery Unit and Solar Energy Assisted System for Building Ventilation(Izmir Institute of Technology, 2012) Özyoğurtçu, Gamze; Mobedi, MoghtadaA study on the ventilation of a building by using solar energy, a heat recovery unit and electrical heater (if it is needed) is performed. The heat recovery unit is used to increase temperature of fresh air by using thermal energy of the return air. Then, the thermal energy stored in a sensible tank is employed to increase the temperature of air leaving the heat recovery unit. If the air temperature at the coil outlet is less than the supply temperature, electrical heater is operated. The study is performed by TRNSYS software for the period of 1st of November to 31st of March. The ventilation system operates from 17:00 to 24:00 where a lower ambient temperature exists compared during the day period. The obtained results show that a ventilation system with solar assisted and heat recovery unit can considerably reduce ventilation energy consumption. The use of solar assisted ventilation system with heat recovery unit reduces energy consumption by 80% if it is compared with conventional ventilation system in which only an electrical heater operates. Furthermore, it is found that the design of ventilation systems without energy of electrical heater is possible. The study s performed by using weather data of Izmir city in Turkey. The supply temperature of fresh air is assumed as 22°C.