Designs for solar off the grid systems
30 Oct 2008
When designing systems to enable house to run off solar power and be off the grid there are numerous factors to take into account.
Often visitors to our Eco Stay ask can we run a washing machine, power tools or an electric kettle for example? The answer is basically a “yes” but within certain limitations. The limitations can simply be addressed by spending more! i.e. installing a larger system allows you to generate and store more power, however the price can be daunting. However if your funding,like most, is not endless then there are steps you must take.
A solar installer should take people through the process of identifying what the power requirements for your house/ lifestyle are. This boils down to the type of appliances, how much power they use and how long each of these appliances run for. Basically an Energy Auditing process.
It is much easier and cheaper to reduce your electrical loads than attempt to just “convert” an existing house to be off grid. For example energy efficient fridges can use a third of the power a usual fridge does. Fridges are often one of the biggest loads in a house as they are on 24 hours a day. Also electric hot water heating is a massive load that can account for a 1/3 of electrical power usage in homes. So identifying the major energy users is the first step, then reducing these loads is the next logical step. It is much easier (and cheaper) to purchase an energy efficient fridge than to install a solar off grid system!
In designing an off grid system the different systems need to be considered as a whole. The design of the building itself needs to be taken into account. For example I see no point in adding solar power to a house located in a cool climate when the house in not insulated adequately! Building orientation, window locations, themal mass and ventilation all dramatically affect the energy use of a house. Thus it is crucial to look at the whole design not just individual pieces of the energy puzzle.
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