multi-objective optimization of a vehicular pem fuel cell
TRANSCRIPT
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
1/24
Multi-objectiveoptimization of a vehicular
PEM fuel cell system
NIDHIN BS7 M2
27227
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
2/24
CONTENTS Introduction Proton Exchange Membrane(PEM) fuel cell ( construction ,
arrangement , modeling )
Multi objective optimization.
Multi objective optimization of PEM fuel cell system. Evaluation of Results.
Observation.
Conclusion.
References.
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
3/24
INTRODUCTION Nowadays with an increase in pollution and the decrease of
fossil
fuel resources a movement has begun towards moreenvironmentally benign and more efficient power production.
Fuel cells are considered as one of the most promisingalternative power sources used in many areas includingtransportation applications, domestic uses, heat production,etc.
Fuel cells have an increasing demand with their highefficiency ( since operating at low temp) and the aim ofthis study is to apply a multi-objective optimization scheme toa PEM fuel cell system used for transportation purposes
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
4/24
Proton ExchangeMembrane(PEM) fuel cell
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
5/24
Main Characteristics The Ballards Xcellsis HY-80 Fuel Cell Engine was used. Fits beneath the floor of the vehicle, the size of the passenger
compartment is not affected.
The engine is a lightweight, 68 kW hydrogen-fueled , fuel cellengine.
The hydrogen is stored in a tank at 10 atm at 298 K
The fuel cell stack is composed of 97 cells each having a 900cm2 active surface area.
The cooling system is used in order to maintain a constant
operating temperature inside the fuel cell stack
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
6/24
Arrangement of PEM fuel cell ina
vehicular system
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
7/24
Modelling
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
8/24
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
9/24
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
10/24
Multi-Objective Optimization Multi-objective optimization seeks the solution to a problem
that has two or more objectives simultaneously.
Objectives of the problem may be conflicting with each othersuch as the search for the best performance and least cost.
There are a set of solutions that one called the ParetoSolution.
The multi-objective optimization problem can be defined as:
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
11/24
Solution methods The alternative solutions to the multi-objective problem
generally are in a conflict with some of the objectives.
The Pareto set is the set of solutions that has minimumconflict. The Weighing Sum of Objectives Method was used inthis study.
The multiple objective functions are combined in one functionas;
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
12/24
Multi Objective Optimization of aPEM Fuel cell In order to apply a multi-objective optimization technique to
the derived model an objective function is to be prepared forthe solution.
In this study, a weighing method is used to form the objectivefunction that is a weighing factor is given to the objective
function parameters which are the produced work , energyefficiency, energy, exergy efficiency, exergy, and the cost ofproduced work.
It must also be considered that cost must be minimized whereas, the other parameters have to be maximized in the search
for the optimum condition.
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
13/24
Continues A selection for the weighing factors is not made, instead a
parametric study for different weighting factors is applied andthe multi-objective problem is separately solved for eachcase.
The fitness function is formed depending on the objective
function derived. The main problem for optimizing this objective function is the
difference in the scales of the parameters.
The values of W lies between 0 and 120 kW, on the otherhand, the values of Cw lies between 2 to 6*10^-3 $/kW.
To avoid this situation the parameters are normalized to formthe fitness function between 0 and 1.
The normalization is done by dividing each parameter with itsmaximum value which is obtained by single optimization of
that parameter by using the developedcomputer programMULOP
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
14/24
So the fitness function is changed as
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
15/24
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
16/24
Some results of the multi-objective optimization procedure
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
17/24
Evaluation of Results
The variation of produced workand efficiencies with respect to
the weight of work in the
objective function.
The variation of producedwork and cost with respect to
the weight of work in the
objective function.
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
18/24
The Variation of produced work andcost with respect to the weight of
energy eff. in the objective function.
The variation of produced workand efficiencies with respect to
the weight of energy eff. in the
objective function.
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
19/24
The variation of produced work
and efficiencies with respect to
the weight of exergy eff. in the
objective function.
The Variation of produced work
and cost with respect to the
weight of exergy eff. in the
objective function.
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
20/24
The Variation of produced
work and cost with respect tothe weight of cost in the
objective function.
The variation of produced work
and efficiencies with respect tothe weight of cost in the objective
function.
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
21/24
Conclusions The change of produced work and energy and exergyefficiencies with respect to the weight of work in the objective
function is seen. It is seen that the work and efficiencies areproportional with each other and when the produced workamount increases the cost of production decreases
It is seen that the best values for efficiencies lies in the lowervalues of contribution but, in these values the produced workvalues are low since the values between 0.5 and 0.6 is muchmore acceptable.
When the variation of the energy efficiency objective weight isconsidered the optimum results for these sets lie in 0.7
weight of the energy efficiency which has the and meaningfulefficiency and produced work results. It is seen that when the weight of an objective increased it
does not guarantee a better result for that objectiveparticularly because of the dynamics and complexity of theproblem.
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
22/24
Continues.. The results for the exergy efficiency objective are similar to
the values of the energy efficiency since both values dependon the performance of the fuel cell system.
When the variation of the work, efficiencies, and cost withrespect to the weight of cost of the production objective
function is observed it is seen that the 0.6 value both thework, efficiencies and cost has the smallest values differingfrom the other sets.
The optimum results seem to lie between 0.8 and 0.9 from,the cost and produced work point of view. If the efficiencies
are considered, the best optimum value seems to be thevalues between 0.3 and 0.4 weights.
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
23/24
References
Multi-objective optimization of avehicular PEM fuel cell systemSuha Orun Mert , Zehra zelik ,Yavuz zelik , IbrahimDiner .
Thermodynamic analysis of a PEMfuel cell power systemM.M. Hussain a, J.J. Baschuka, X. Li a, I. Dincer.
A grid based multi-objectiveevolutionary algorithm for theoptimization of power plants
J. Dipama a, A. Teyssedou a, F. Aub b, L. Lizon-A-Lugrin a
-
8/2/2019 Multi-Objective Optimization of a Vehicular PEM Fuel Cell
24/24
THANK YOU