SolarPlus has specific tools for modelling Off-grid systems (aka SAPS), namely
Off-grid systems follow the same system design approach as grid-connect, with some minor changes.
Generator Run time and fuel cost calculations
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On the Energy page, under Energy Costs, select ‘Off-grid’.
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You will then be prompted to choose between:
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Compare with 100% Generator. Choose this option if the client is currently running a generator to supply their loads.
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Compare with Grid Connection. Choose this option if the client currently has no power and is comparing the cost of connecting to the grid against an off-grid solar and battery system.
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Generator Running Cost
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Tariff Name: Enter a unique name for this generator run cost profile, such as “Staunch 10kVA”
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Generator kVA Output. This is the nameplate kVA rating.
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Genset Fuel Consumption (litre/hr): You have the option to add this value if you know it from past consumption or generator specs. A typical value for a 10kVA Genset is 1.7L/hr.
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Genset efficiency: The default efficiency of the generator is 30% and can be adjusted.
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Genset Power Conversion (kW/litre): The default of 10.607kW/L suits most situations, but can be altered.
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Diesel Cost ($/litre)
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Genset Maintenance Cost: This is the cost of maintaining the Genset as a percentage of the running costs. This can be hard to quantify but can be considerable, so is worth including in the energy cost. This value is set at 25% by default.
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Generator Load factor: This is a percentage of the nameplate capacity load. This is used for the indicator of generator suitable size in relation to the consumption. Ie if max. demand is 74kVA, and there is a 100kVA genset with a load factor of 75% then this will be deemed suitable. This is not used to indicate the generator power provided to the inverter/charger, which is set at 75%.
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Genset kWh cost – This field considers all the variable parameters above to calculate the kWh cost.
Off-grid Load Profile Builder
Go to Off-grid Load Profile Builder
DC-Coupled MPPT charge controllers
DC-coupled charge controllers are managed in SolarPlus in the same way as PV Inverters and can be selected under the Inverter section on the left-hand side.
Off-grid System Performance Modelling
The Design Review page is similar to grid-connect systems, with the addition of a generator supply in place of the grid.
Consumption vs Production by Month
SolarPlus calculates the generator run times (green dotted line) for each month along with the comparison of Energy consumption, Solar production and Genset supply figures(dark blue bars) for individual months.
Please note that due to limitations with typical year meteorological data, generator run-time and battery hours of autonomy calculations do not account for the absolute worst case scenarios of long rain events during La Nina years, so we encourage designers to use common sense when sizing off-grid power systems to take this into account. Learn more here.
Daily Performance
To check that you’ve sized the system well, the most useful view on this chart is the Weekly View, which shows a series of 7 days. Select the month which has the worst sunshine, and check each week of that month to ensure that the battery charge and discharge, and generator runtimes are as you would like them to be.
You can simplify the graph by de-selecting unwanted parameters, and just showing specific ones, such as Genset Supply and Battery Charge.
Off-grid proposal template
When your design and quote are finalised, be sure to select the Off-grid proposal template to send to your customer. This can be customised to suit your specific needs.
Off-grid SLDs and System Handover Manuals
On the System Designer page, on the right under Grid Configuration, select Off-grid. This will ensure that the correct handover manual template and SLD structure is used.
Tags: off grid RAPS stand alone, stand-alone
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