PhD Thesis - Energy Systems Research Unit - University of Strathclyde

7.2.1 Fuel Supply Specification
For the fuel supply profiles, the accuracy of the timing and magnitude of the fuel
supplies and energy requirements were tested against expected results. The
provisions for seasonal and continuous supplies, and for batch and continuous
production were all analysed in this manner as necessary for each system type.
Where multiple energy requirements for the same energy type were specified,
these were tested individually, and in combination. The overall required inputs
and outputs over the time period were also calculated and compared with the
information given in the information box. The mechanism for taking the fuel
availability through to the matching procedure and creating a storage profile was
tested at the matching stage by comparing the magnitude and shape of the fuel
storage profiles created when no fuel is used with expected results. The profiles
created when fuel is used were considered when checking the load following
supplies, and this is discussed later.
To show how these verifications were carried out, the fermentation system has
been taken as an example, as this is the most complicated model. Firstly, the
continuous process with a constant supply is analysed to ensure the correct
behaviour is being modelled when there is not enough fuel for the fermenter to
run continuously. A simulation period of seven days is chosen for clarity. The
input parameters are shown in Figure 7.3, and the output graph (Figure 7.4)
shows correct fuel production and energy use at the times when enough fuel is
available, and no production or energy use when there is insufficient fuel, giving
expected production times and magnitudes. The production and energy use
rates, and the overall production and consumption figures in the information box
(Figure 7.5) are also correct. When the exact amount of feedstock is available,
the process runs continually (Figures 7.6). This is also the case when too much
feedstock is available, but a residual fuel supply is shown, which correctly
accounts for the degradation rate (Figure 7.7). Figure 7.8 shows the fuel
storage graph obtained, at the matching stage, from the continuous output,
which shows the correct graph shape and magnitude. When the output is not
continuous (i.e. as in Figure 7.4) this profile is stepped.
226