By Jenny Griffin
Energy from the sun is free, and can be used to heat water or to power electrical appliances in domestic residences. Below we’ll walk through the two diy solar power methods – solar hot water and solar photovoltaics (electricity).
Using solar energy for domestic water heating is one of the most cost-effective ways to reduce your power bill and the carbon footprint of a household.
Either evacuated tubes or flat plate collectors can be used for diy solar hot water. A conventional boiler or immersion heater can be used to produce hot water for those occasions when the sun does not oblige, which is often necessary for night-heating or in countries where sun exposure is weak in winter .
The type of system chosen depends firstly on whether freezing is likely to occur. In climates where freezing is not a problem, there are three main options:
A batch heater employs a storage tank for collection; a direct pump system moves water from a collector to a storage tank; and a thermosiphon system uses gravity, and no pump.
If temperatures are low enough to cause freezing, then drainback or closed loop systems with heat exchangers and antifreeze will be required.
Drainback systems use distilled water to transfer heat, while closed loop systems circulate antifreeze and use a heat exchanger to transmit the heat to prevent freezing .
Most people choose to have solar photovoltaic (electricity-producing) panels installed on the roof of their homes as this provides elevation and consequently less chance of the panels being shaded by surrounding buildings and trees.
If the panels are at the same angle as the roof, they are afforded better protection from the wind, and are less likely to be damaged.
There are, however, some limiting factors: the roof must provide sufficient space to accommodate the solar panels, the roof structure needs to be strong enough to support the weight of the solar panels, and the roof must face the sun (face south in the northern hemisphere and north in the southern hemisphere), and it must be unshaded for most of the day.
If solar panels are at a different angle to the roof, planning permission may be required.
Non-roof-mounted solar panels allow for increased flexibility in placement and are suitable for use in circumstances where the roof does not meet the above requirements .
While solar panels are expensive to install, once installed they require very little maintenance, and will yield value for many years to come – the resultant savings on electricity bills could quickly exceed the cost of installation and maintenance.
In addition, rebates and tax credits are often available, with a tax credit of 30% of the cost offered in the United States. Households with large electricity bills will experience the greatest financial return on this investment.
Solar panels can also greatly increase the value of a house, with potential buyers seeing the potential electricity saving as a huge incentive.
Having a solar electric system installed by a company is expensive, so many people prefer to buy DIY kits, or to build their own.
For those that are not daunted by technical details, the task of building a DIY solar panel can be completed in a very short time. Solar panels can be easily constructed using parts obtained through Amazon, eBay, or from the local hardware store.
The most expensive component of a solar panel is the solar cells, which are made from crystalline silicon and conducting metals that convert sunlight to electricity.
To save costs, blemished or damaged solar cells in working condition can often be picked up at a much lower price than the cost of cells that are in perfectly new condition.
A total of 36 3’x6’ solar cells will be required for a complete solar panel (other sizes are available and can be used, just make sure you buy cells of uniform sizes and wattage).
The cells should be wired in series by soldering, leaving some space between the cells to allow for expansion when they are heated by the sun.
Normally each cell will generate roughly 0.5 volts, so 36 cells in series will produce around 18 volts, which is sufficient to charge a 12 volt battery.
Other equipment that is necessary to complete the system include: an inverter to convert the DC current of the solar panels to AC current used by household appliances; deep-cycle batteries to store surplus energy; and a charge converter to ensure that batteries are not overcharged, or excessively drained.
Once the solar cells are wired together in series, they are attached to a backing-board and secured in a protective box casing built to house your solar cells.
This must be shallow enough to allow sunlight to reach the cells without being inhibited by the sides.
The front of the protective box casing is covered with a durable clear plexiglass front to protect the unit from the weather.
You’ll need to weatherproof your unit by sealing the joins with silicon and painting the backing board if you’re using plywood.
This post was last modified on April 5, 2019 2:37 pm