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Mechanical Engineering

Mechanical Engineering

Energy Systems
Energy & Thermofluids
graduate student with a professor


The increasing consumption of fossil fuels has led to a dramatic increase in environmental issues such as global warming, ozone depletion, and atmospheric pollution. Since energy use continues to grow as a result of population increase and expanding economies across the world, search for sustainable energy sources and the improvement of energy efficiency have to be addressed simultaneously in order to meet this expanding worldwide energy demand coupled with environmental challenges. In fact, there is a great potential for reducing the use of fossil fuels by recovering low-grade waste thermal energy sources. It has been estimated that more than 50% of the heat classified as “low-grade waste” in the industrial processes is directly rejected to the atmosphere. In general, a thermal energy source is considered to be moderate to low grade if its temperature is lower than 500°F.

Low-grade thermal energy recovery from industrial processes, from solar irradiation, or from geothermal sources may be an eco-friendly resource for power generation as well as heating and cooling purposes. Organic Rankine Cycle (ORC) is one of the candidates to exploit low-temperature thermal energy sources, otherwise difficult to access using conventional power generation systems. We will develop a test bench as well as modeling tools to assess the thermodynamic model of an ORC, with the final short-term goal of optimizing the conversion efficiency, especially for micro-CHP applications. The simulation model will be developed in the Matlab®/AMESim® environment to allow system modeling both for steady and transient analysis. The model predictions will be validated both numerically and experimentally.

We plan to build, test, and possibly commercialize an ORC system with reasonable efficiency at an affordable cost. To facilitate this long-term goal, as an offshoot of this signature area, we plan to develop research projects that deal with selection of suitable working mediums for selected thermodynamic cycles targeting low grade thermal energy recovery. We also plan to develop a logistic regression-based classifier to predict the probability of any working fluid as a desirable candidate for the ultra-low grade heat driven organic Rankine cycle. Criteria such as global warming abilities, ozone depleting potentials, toxicity, flammability, atmospheric lifetime, as well as thermodynamic properties of the working medium will be used as parametric classifiers. As a validation, we will cover over 80 working fluids to be screened and rated.

Drs. Beyene, Miller


Dept. of Mechanical Engineering, E-326

San Diego State University

5500 Campanile Drive

San Diego, CA 92182-1323