How to use the tool

Step 1 - the site

Choose the site type - Home, Small office, Commercial building or Industrial / plant - then either start from a scenario (apartment, villa, 10-desk office, clinic, shop) or from scratch. Pick the site country so the tool uses the right peak sun hours, and set the supply phase.

The site type does real work: it selects the coincidence table. A commercial building diversifies hard, because its circuits rarely peak together; a process plant barely diversifies at all, because production schedules mean the loads genuinely do run together. Commercial and industrial sites also inherit the whole office load catalogue, so nothing is missing from the list.

Step 2 - the loads

Work through the categories and set three things for each appliance:

• How many units there are.
• Hours per day it actually runs.
• Backup priority - Essential, Important or Comfort.

The priority is the most important decision on the page. It decides what stays alive in an outage, and therefore how big the battery has to be. Anything not in the list can be added as a custom load.

Step 3 - the backup

Two choices drive the battery:

• Which loads stay on - Essential only, Essential + Important, or Everything.
• How long for - the backup window in hours.

Set the solar fraction if you want the array to cover less than a full day's energy, and enter your tariff for the savings estimate.

Step 4 - the system

You get the inverter, battery and PV size, the full working behind each, warnings where something needs attention, and ranked equipment combinations from the catalogue.

Underneath sits the bill of materials: DC and AC cable, combiner boxes, protection, mounting structure, earthing, monitoring and accessories, each quantity derived from the sizing. The BOM tracks the size of the system - a 4 kW house is quoted 6 mm2 AC cable, a 750 kW plant is quoted busduct - so it stays credible across the whole range.

Save it to get a reference, a shareable link and a printable report.

Tips

• A fridge runs 24 hours but only draws power about a third of the time - that is the duty cycle, and it is already handled.
• Fixed-speed air conditioners and pumps draw three to four times their rated power for a second when the motor starts. That often sets the inverter size, and the results page says so when it does.
• If the battery is "sized by power, not energy", a higher C-rate battery will be cheaper than simply adding capacity.