Watch the video presentation and/or read the full text below
The transformation side of this is directly comparable to the structure for space.
In this case, the stated assumption is that each chassis has a power consumption
of 200 W:
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Create a new transformation, and name it
Power required.
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Connect from Access chassis to
Power required, using the quick-link target.
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Open the Input and Transformation dialog. The
Input is already wired up.
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Set the Output Unit and
Multiplier inputs as shown below. As we did with the
service, we are matching our units to the resource by entering 0.2 kW rather than 200 W.
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Connect on from Power required to
Power, and choose
Requirements when prompted.
Figure 43: The Multiplier input
governs the power consumption in kW per chassis
This means that each installed unit of the chassis requires 0.2
kW of instantaneous capacity from the Power resource.
(At that rate, a kWh of capacity will last five hours.)
We will quickly check the arithmetic as we did before:
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Run the model. The Results program is activated.
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Draw the graph Instantaneous Output for
the transformation Power required. This starts
at 5 kW (0.2 kW × 25 units), and then gradually increases to 5.6 kW.
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Checking the opex is harder, as we need to count how many hours there are
in a year. STEM does this for us, and has thus worked out how much energy is consumed.
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Draw the graph Consumption for the resource
Power. Working with the easier (round) number for
Power required, this starts at 43 800 kWh
(5 kW × 24 × 365).
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Add Power to the stacked
Operating Costs graph, and check the numbers in a
table. The annual opex for Power starts at
USD 6570 (USD 0.15 × 43 800 kWh).
If you were to run the model in quarters or months, STEM would count the number
of hours in a quarter or a month in order to calculate the quarterly or monthly
opex. How would these graphs look then?
(Beyond the scope of this tutorial.)
Figure 44: The Consumption graph reveals how many
kWh are used-up in the period
For simplicity, we have only considered the power requirements of the chassis (as
we did more justifiably for floor space).
Similar transformation drivers may be added for any resource that has an explicit
power consumption. These can be connected to the same Power
resource and its consumption will correspond to the aggregate demand.
(Beyond the scope of this tutorial.)
Things that you should have seen and understood
Consumption