Household Utilities: Sustainable Energy: Solar.

Energy Source

A photovoltaic (PV) array is an assembly of solar cells, which convert sunlight directly into electricity. Brisbane has on average 2738 annual sunshine hours per year, with a mean of 8.0 hours per day.

PV cells produce on average energy equivalent to their rated peak outputs, 6 hours per day in ideal situations in a Queensland summer, down to nil in overcast situations.

Specific Requirements

A PV array is custom designed for the power requirements of a particular household and site. It must be installed facing north, at a tilt angle dependent on latitude 308 is ideal for Brisbane - and obstructed by trees and shadows. Placing the modules on a solar tracking mount will achieve a 10-50% gain in power output.

The Newton House has full exposure to the winter sun with no interruption from terrain or buildings, though there is some shading from local trees. The house has been designed to balance the occupier's need for sun while keeping the footprint minimal so as not to disturb the local natural fauna and flora by excessive clearing.

Once generated the power is stored in batteries until the current until it is required. The power is then changed from DC to AC power using an inverter so that it can be used on conventional domestic appliances.

Options Available

PV cells produce between 40 and 83 watts of DC power. There are 3 types of PV cells available:

1. Monocrystalline silicon cells, thin wafers of silicon cut from a single crystal to form single cells. This system has the best efficiency.

2. Polycrystalline silicon cells, thin wafers cut from a block of multiple crystal silicon. Their efficiency and life span are only slightly less than monocrystalline, but they are a significantly lower price.

3. Amorphous silicon modules (or Thin Film Silicon) are made from an uncrystallised form of silicon.

Links
http://www.greenhouse.gov.au/renewable/technologies/solar/index.html
http://renewable.greenhouse.gov.au/technologies/pv/pv.html