Phd Degree / Doktora
Permanent URI for this collectionhttps://hdl.handle.net/11147/2869
Browse
2 results
Search Results
Doctoral Thesis An Experimental and Numerical Study on Heat and Mass Transfer in Adsorbent Bed of an Adsorption Heat Pump(Izmir Institute of Technology, 2012) Gediz İliş, Gamze; Mobedi, MoghtadaBecause of the limited conventional energy sources, the improvement of thermal heat pumps has gained attentions of researchers in recent years. Adsorption heat pump, which is a kind of thermal heat pump, can be directly operated with the low temperature heat sources such as waste heat, geothermal and solar energy. Although, adsorption heat pump has many advantages compared to the conventional heat pump, there are still many difficulties for its practical application. Adsorbent bed is one the most important component of adsorption heat pump. Heat and mass transfer in the adsorbent bed should be accelerated in order to attain a small sized, high powered adsorption heat pump. In this thesis, a theoretical and experimental study is performed on heat and mass transfer in an adsorbent bed. A detailed literature survey on the design of adsorbent bed is done. The designed adsorbent beds are classified, and their advantages and disadvantages are discussed. In order to analyze heat and mass transfer in an adsorbent bed, transport of adsorptive in an adsorbent particle should be well known. A theoretical study on heat and mass transfer in a single adsorbent particle located in an infinite adsorptive medium is performed to understand the effects of internal and external heat and mass transfer resistances. Heat and mass transfer equations for an annular adsorbent bed are derived for uniform and non-uniform pressure approaches and numerically solved to determine temperature and concentration profiles in the bed. These equations are also non-dimensionalized to reduce number of governing parameters. The non-dimensionalization of the equations yields important dimensionless parameters that can be used not only to describe heat and mass transfer in an adsorbent bed but also employ them during design of the bed. Furthermore, an experimental setup was designed and constructed to validate the obtained numerical results. The experimental results were compared with the solution of the numerical results and a good agreement was obtained between them.Doctoral Thesis Simulation of the Heater Test Room Defined by En 442 Standard and Virtual Testing Og Different Type of Heaters(Izmir Institute of Technology, 2011) Erdoğmuş, Abdullah Berkan; İlken, ZaferHeat outputs of radiators are determined experimentally in specific conditions. Many standards have been developed to identify test conditions. EN442 standard specifies test room properties, temperature measurements and heat output calculations for radiators. In this study, the heat dissipation capabilities of three different panel radiators were determined by using numerical methods. The height and length of the tested radiators were 600 mm and 1000 mm, respectively. An experimental study was conducted in the standard test room in order to determine boundary conditions for computational study and verify numerical results. Tests were carried out in three different operating conditions. Twelve measurements were performed in each condition when test room reached steady state. Turbulent typed air flow in the test room and water flow inside the tested radiators were simulated. Temperature and velocity contours in virtual test room are also investigated in this study. Non uniform temperature distribution on the front surface of tested radiators was observed. It is seen that the symmetricity in velocity contours is distorted by using more complex radiator models and increasing excess temperature. The difference between experimental and computational heat output fluctuates between 0.4% and 13.6% for the simplest model, 3.4% and 11.1% for the second radiator, 4.5% and 12.9% for most complicated model investigated in this study. Good results are obtained for the excess temperature of 50oC and 60oC. For the lowest excess temperature, results are also in acceptable range. The study shows that computational methods can be applicable in the design of new heater types.