3.3 Benchmark Experiments
Assessing the effectiveness of the proposed Genetic
Algorithm (GA) method was conducted through two
distinct sets of experiments, categorized based on
the temperature of the mixtures: 5°C, 10°C, 15°C,
20°C, and 25°C (referred to as sets hereafter):
(a) Set 1 - Priority on Cost: The importance
assigned to the weight value (w_(1)) assigned to the
cost aspect in the Evaluation Function TMFV was
set to 50% or higher.
(b) Set 2 - Priority on Density: The significance
attributed to the weight value (w_(2)) attributed to
the density aspect in the Evaluation Function TMFV
was also set to 50% or higher.
(c) For both Sets: The population was consistently
150 individuals, evolving over 200 generations. The
ingredient costs were predetermined: diesel priced at
2.0000 €/liter and biodiesel at 0.7901 €/liter.
Furthermore, the ingredient densities were
established at diesel 0.8191 g/ml and biodiesel
0.8855 g/ml at 5°C. The ingredient densities varied
depending on temperatures ranging from 5°C to
25°C.
(d) In each subsequent generation, the top 10% of
chromosomes from the previous generation, based
on their performance, were directly carried over.
(e) The crossover operator produced 70% of the
population, with the IPLS value selected randomly
for each generation, fluctuating within a range of
±5% to 10%.
(f) The mutation operation was implemented on the
remaining 20% of the chromosome set.
(g) Every experiment involved conducting 1000
separate simulations for each Set and temperature
variation (for instance, Set 1 - 5°C - 1000 iterations,
Set 1 - 10°C - 1000 iterations, ..., Set 2 - 25°C -
1000 iterations).
Biodiesel, functioning as the secondary
component, is sourced equally from two primary
origins: The mixture contains an equal amount of fat
from animal and plant origins. The expenses
associated with plant sources, specifically rapeseed
oil and sunflower oil, can be accessed globally
through the [17], as well as locally in Greece via the
[18].
Within Greece, 15 companies are tasked with
collecting animal fat and processed olive oil. The
prices of these components are shaped by refinery
demands, consequently impacting the ultimate price
of biodiesel.
The groups of experiments are categorized
according to temperature ranging from 5°C to 25°C.
Set 1 emphasizes cost (w1 ≥ 50%), while Set 2
emphasizes density (w2 ≥ 50%). For instance, when
w1 equals 70% and w2 equals 30%, the focus is on
cost, indicating that cost is considered more
significant than density.
Set 1: Half and half (50% / 50%), Sixty-
forty (60% / 40%), Seventy-thirty (70% /
30%), Eighty-twenty (80% / 20%), Ninety-
ten (90% / 10%)
Set 2: Equal split (50% / 50%), Forty-sixty
(40% / 60%), Thirty-seventy (30% / 70%),
Twenty-eighty (20% / 80%), Ten-ninety
(10% / 90%)
Additional experimental details are provided:
Diesel is priced at 2.000 €/l, while biodiesel costs
0.7901 €/l. Additionally, the density ranges from
0.8191 g/ml to 0.8855 g/ml, varying with
temperature. Moreover, the percentages of
ingredients in mixtures are specified, with diesel
ranging from 1% to 99% and biodiesel from 1% to
30%. These values reflect the availability and actual
prices during the laboratory experimentation period.
3.4 Experiments Results
Initially, the performance of the suggested Genetic
Algorithm (GA) was assessed in Set 1. This
involved conducting 25,000 independent
simulations for each combination of temperatures
(ranging from 5°C to 25°C) and weights (w1 and
w2). The total duration of these simulations
amounted to 3,536.29 seconds (equivalent to
approximately 59.41 minutes or roughly 1 hour).
Figure 2 contains information about the
biodiesel evaluation criteria of Set 1 and Set 2
experiments at a temperature of 5°C. For all w1 and
w2 combinations of priority on cost (w1 ≥ 50%) and
for all w1 and w2 combinations of priority on
density (w2 ≥ 50%) are presented the cost and the
density of the evaluated fuel mixtures. For example,
in group w1 = 90% and w2 =10%, the blue column
refers to the cost criterion = 1.6981€/l, which is part
of Set 1 (priority on cost). On the other hand, the
yellow column (w1 = 10% and w2 =90%) concerns
the cost criterion = 1.7787 €/l, as part of Set 2
(priority on density).
The ideal fuel blend in Set 1, at a temperature of
5°C with weights distributed evenly between w1
and w2, consists of 75.031% diesel and 24.969%
biodiesel. The Total Mixture Function Value
(TMFV) is recorded at -0.0727, with the mixture
costing 1.6975 €/l and having a density of 0.8355
g/ml (Figure 2).
Set 2 provides details regarding the optimal
mixture derived from 1000 independent simulations,
resulting in a total of 25 optimal mixtures. The
evaluation is centered on minimizing the Total
Mixture Function Value (TMFV). With an increase
in the value of w2, the TMFV also increases,
WSEAS TRANSACTIONS on ENVIRONMENT and DEVELOPMENT
DOI: 10.37394/232015.2024.20.23
Vasileios Vasileiadis, Marios-Errikos Kyriklidis,
Christos Kyriklidis, Eirini Terzopoyloy,
Constantinos G. Tsanaktsidis