Friday, 11 April 2008

Rules of thumb for sizing solar panels

Whilst each solar hot water system should be designed properly, it is helpful to have a method for estimating the size of the system components. 
  1. 1sqm per person - This means for each person in the household, there should be 1 square metre of flat plate solar panel area. This rule assumes a south-facing pitched roof.
  2. 50Litres/sqm - For each square metre of solar panel area, there should be around 50 Litres of hot water storage in your hot water cylinder.
Example
Lets say there a 4 people in your house. You would want 2 solar panels of 2sqm each (2m x 1m). To suit this system, there should be around 200 Litres in your hot water cylinder.

Note: The system should be sized for the permanent occupants only for maximum efficiency. grossly over or under-sizing the system can reduce the efficiency.

1 comments:

Anonymous said...

These rules of thumb tie into my experience over the last 6 months.I have 5 people in the house, and have a 250 litre tank with a 3.3m2 panel (vac tubes) I really should have bought 4 or 5 m2 of panel. Only on the very very sunniest of days does the panel "do the biz" - heat all the water up to 50 deg+