PhD Thesis - Energy Systems Research Unit - University of Strathclyde

Figure 7.35 Second Engine: Following the Heat Demand
The overall fuel use data was checked for various combinations of auxiliary
supplies to ensure that the amount of fuel used by the individual supplies was
added correctly if different supplies were using the same fuel. In the case where
there was not enough fuel, the supply chosen first gets the initial opportunity to
use the fuel, with subsequent supplies using any residual fuel. The amount of
fuel used overall plus the amount remaining in storage at the end of the period
should equal the overall fuel production for that period, and this was the case in
all examples tried. Where seasonal supplies were considered, it was verified
that the appropriate amount of each fuel left at the end of the simulation period
was being taken through to start the second simulation period by studying the
shape of the fuel storage graphs produced. For example, Figure 7.36 shows a
seasonal ethanol storage graph where no ethanol has been used. When the fuel
is used by one or more sources, this is still dealt with in the correct manner.
Where an electrolyser was used to create hydrogen using excess electricity, as
shown in Figure 7.37, this was done in the correct manner, and in the correct
order, allowing hydrogen to be available to supplies chosen after the
electrolyser, and added to the supply profile if not used.
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