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switched from one fuel tank to the other during operation. lower than operation using standard diesel, with a BTE of
Four different fuels were tested, with coconut oil as the 24.2% at the highest load;
representative vegetable oil. The fuels tested were diesel; • The highest levels of engine efficiency are recorded for
neat coconut oil; a blend containing 10% methanol, 27% operation with the M30 blend;
biodiesel and 63% coconut oil by volume (referred to • The BTE for the M10 and M30 blends are all higher than
as M10); and a blend containing 30% methanol, 21% those for neat coconut oil;
biodiesel and 49% coconut oil by volume (referred to as • The values of BTE for M30 are higher than those for
M30). The proportions of the three components in the M10;
blend were determined from previous blend stability tests. • Most importantly, the BTE for the M30 blend surpasses
The main results are shown in Figure 1. that for neat diesel operation at the highest loads, with
values of 28.6% and 26.1% respectively;
Table 2: Engine specifications
Manufacturer Plint Engineers (UK) The higher BTE values for the M10 and M30 blends at
Bore/mm 87.3 higher loads when compared to standard diesel, is a
Stroke/mm 110 welcomed result, as most engines being used for electricity
generation usually operate at high loads consistently.
Swept volume/cm3 659 These results clearly indicate that efficiency increases
Compression ratio 16.5:1 with methanol addition. It is likely that this increase can

Rated speed rev/min 1800 be attributed to the presence of methanol, which leads to
a more effective combustion process. Consequently, as
Capacity /kW 7 methanol volume increased from M10 to M30, the BTE
value also increased.
Figure 1 shows plots of brake thermal efficiency (BTE) for Economic Assessment
the various mixtures tested in the engine. As expected, A statistically based cost estimate model for the power
engine efficiency increases with increasing load. It can be generation cost of the proposed chain was developed
seen from the figures that: based on the previous efforts of the authors. This model

sought to capture the price variations of key components in
• The lowest engine efficiencies occur for neat coconut oil the power generation chain and examine their influence on
operation; efficiency for operation with neat coconut oil is

Figure 1: Engine test results for various loading conditions

INDUSTRY JOURNAL 10