Design, Production and Testing of a Laboratory Scale Organic Rankine Cycle System (Onur Kardaş – M.S.)

This study presents the thermodynamic design, implementation and commissioning of a small scale organic Rankine cycle test bed. The objective is to design a flexible organic Rankine cycle test bed to study performance of different working fluids and cycle components. The test bed is instrumented with pressure, temperature and flowmeter sensors to collect data from cycle operation. These data will be utilized to validate various thermodynamic models. During the design process environmental, safety issues and physical properties of 13 different fluids are studied  to obtain suitable working fluids.  Four fluids namely R134a, R141b, R245ca and R245fa are taken into consideration for further detailed analyses. An organic Rankine cycle system which is capable of operating with all these working fluids is designed and built. [more]

3D Radial Inflow Turbine Design And Analysis For A Laboratory Scale ORC Application (Emre Sezerkan – M.S.)

In this study, the aim is to design and analyze a single stage subsonic radial inflow turbine for the Organic Rankine Cycle system established in Boğaziçi University Renewable Energy Technologies Laboratory, by using R245fa and R134a as the working fluids. Complete design process of the ORC turbine, from preliminary design to 3D blade design stage, is presented. Design point of the turbine is determined according to the cycle limitations and by comparing the maximum Mach number, rotational speed and mass flow rate parameters as a result of detailed preliminary turbine design and basic cycle analysis. Results of the streamline and CFD analysis of the designed turbine are compared and discussed from the point of Mach number distribution, turbine efficiency and power output. The comparison shows that the two analyses give similar efficiencies, power outputs and Mach number distributions. Finally, the performance charts of the designed turbine are generated for both R245fa and R134a. Streamline analyses results show that the maximum total to static isentropic turbine efficiency and power output are 87.5 % and 3.97 kW respectively. [more]

Evaporative Cooling using Spray Water (Mehdi Nabati – PhD)

Evaporative cooling is a technology that can be utilized in natural draft cooling towers. The advantage of this technology is lower consumption power. The main objective of this project is to design and test an evaporative cooling system using water spray nozzles. The main problems in this type of cooling systems are partial evaporation and non- uniform distribution of temperature. This project will investigate the effect of critical parameters for solving the mentioned problems. BURET low-speed wind tunnel, water supply system and Particle Image Velocimetry system (PIV) will be used for conducting experimental tests. [more]

Parameter Optimization Of Alpha, Beta & Gamma-Type Stirling Cycles For Waste Heat Recovery From A Heavy-Duty Truck Engine (Metin Güven – PhD)

This study demonstrates a first order analysis by using Schmidt  method, to investigate possibility of waste heat recovery (WHR) using Stirling engine from a heavy duty diesel. Alpha, Beta, and Gamma type Stirling engines are analyzed. Effect of each parameter in the work equation is defined and an optimum design for a set of given boundary conditions (temperature, pressure, total volume inputs) is obtained. Theoretical analysis shows that Beta-type Stirling engine is the most suitable for WHR. Further analysis for Beta-type will be done with second order analysis by considering efficiency of the exchangers and other heat losses. [more]

1-D  Compression-Ignition Engine Simulation and Comparison of Soot Emission Models (Alpay Asma – M.S)

The aim of this paper is to develop an engine model that can predict the performance and soot emission trends of a selected engine under full load. With this aim PUMA GLOBAL 2.2 liter 125 PS CI engine having 4-cylinders with turbochargers has been modeled numerically. The work can be divided into two stages including validation of thermodynamic & performance based results of the selected engine, and correlation of selected phenomenological soot models with measured data at all 35 speed modes ranging from 1000 to 4400 rpm. In order to predict the heat release rate, and calculate the in-cylinder pressure and temperature values with good accuracy, multi-zonal combustion model called as Vibe 2-Zone is used. [more]