Problem statement Methodology State of Progress

Meeting of the Industrial Energy Efficiency Chair

Franco Cascella, PhD candidate

Supervisor: prof. Mikhail Sorin, Department of Mechanical Engineering, Universite de Sherbrooke,

Co-advisor: prof. Alberto Teyssedou, Department of Engineering Physics, Ecole Polytechnique de Montreal;

Consultant: prof Fabien Formosa, Laboratoire SYMME, Universite de Savoie

Shawinigan, November 28th, 2014

Meeting of the Industrial Energy Efficiency Chair Franco Cascella 1 / 8

Problem statement Methodology State of Progress

Problem Being Studied

Research Question

Optimization of Stirling engines (macro and micro) in the contextof waste heat recovery from aluminum production.

In US, the industrial sector consumes 30% of the energy demand;one-third of this is discharged to the environment1.

Therefore, the analysis of power systems used to recover wastedheat becomes significant;

Cogenerative systems;Micro Stirling Engines;

1Engineering Scoping Study of Thermoelectric Generator Systems for Industrial Waste Heat Recovery, Terry

Hendricks, Pacific Northwest National Laboratory, William Choate, BCS Incorporated, Report to U.S. DOEIndustrial Technologies Program, November 2006.

Meeting of the Industrial Energy Efficiency Chair Franco Cascella 2 / 8

Problem statement Methodology State of Progress

Engine Under Analysis

Stirling Engine

Collaboration with professor Fabien Formosa, from Universitede Savoie;

The behavior of the engine could easily predicted;

Meeting of the Industrial Energy Efficiency Chair Franco Cascella 3 / 8

Problem statement Methodology State of Progress

Modeling By Using The Electrical Analogy

Formosa2 employed an electrical analogy to study his Stirlingengine;

Engine variables Electric VariablesPressure p Voltage VVelocity u Current i

Pressure Drops L Inductance LCompressibility C Capacitor C

Viscous and thermal effects Rν , Rα Resistance RMechanical power Electrical power

L Rν

C Rα

u

p

u + ∆u

p + ∆p

2Formosa F., Badel A., and Lottin J,. ”Equivalent Electrical Network Model Approach Applied to a Double

Acting Low Temperature Differential Stirling Engine.”Energy Conversion and Management 78 (2014): 753-764.

Meeting of the Industrial Energy Efficiency Chair Franco Cascella 4 / 8

Problem statement Methodology State of Progress

Analyzed Variables

Electrical circuit describing the engine behavior;

Pressure, temperature and flow rate evolution could bepredicted −→ Continuous variables;

Zexp,b

Zhot,a

Zhot,b

Zreg,a

Zreg,b u1

Zcold,a

Zcold,b Zcomp,bp + ∆p

u + ∆upu

However, the other variables affect the engine performances;

Materials;Links among the elements;Time periods;

Discrete variables

Meeting of the Industrial Energy Efficiency Chair Franco Cascella 5 / 8

Problem statement Methodology State of Progress

Optimization Using A Superstructure Approach

Therefore, to optimize the performance of an engine, a set ofcontinuous and discrete variables must be found;

Continuous and discrete variables could be introduced in asuperstructure;

The electrical analogy can be employed to analyze continuousvariables;A set of switches can be implemented to take into accountdiscrete variables;

Hence, the superstructure will analyze how the engineresponds to the change of both continuous and discretevariables and will find the combination of them thatmaximizes the performances;

Meeting of the Industrial Energy Efficiency Chair Franco Cascella 6 / 8

Problem statement Methodology State of Progress

Project Advancement

Where Are We Now?

At this point, we are analyzing the electrical analogy;

Formosa has neglected the effects due to the gas-temperaturevariation;

Rectification of Farmosa model by adding the non-isothermalconditions;

Meeting of the Industrial Energy Efficiency Chair Franco Cascella 7 / 8

Problem statement Methodology State of Progress

Thank you for your attention!

Meeting of the Industrial Energy Efficiency Chair Franco Cascella 8 / 8