Residential solar power system
Posted by Solar energy guru | Filed under Solar power systems
Deciding on the best choice for a residential solar power system can be challenging with so many competing products on the market. Before buying one, it is essential to know how these systems work and what components are required. While they are generally expensive, these systems can potentially make back their cost in a few years by reducing the need to buy electricity. They can even make money through net metering.
Before any solar power system can be considered, an audit of household power usage should be done to get a rough indication of the size and cost of the system required. This can be done by taking a daily reading of the electricity meter for several days, and then calculating an average. To work out the required power of the system, divide the average reading by the number of hours of direct sunlight per day, which is five hours in most places. For example, a home that uses twenty-five kilowatts hours per day would need a five kilowatt system. Buying a system large enough to meet total demand is expensive, but it’s possible to use a smaller system to meet part of the demand. The cost savings will not be as great but it will still save money.
The typical home solar power system comprises photovoltaic panels, batteries, controller, and inverter. Since one panel cannot meet the energy needs of a home, several panels are wired together to create a large photovoltaic array. This increases the output power while maintaining the low output voltage. It is safe to handle the solar panels because there is no risk of electrocution at this voltage. The array can be mounted anywhere but is usually put on the roof that gets the most sunlight. In the case of flat roofs, a supporting structure should be used to incline the panels towards the sun. The panels are quite heavy and the effect of their weight on the roof should also be considered. An alternative to large panels is to use many smaller panels, called solar shingles or solar tiles. These are distributed over the entire roof and blend in much better than large panels.
The solar panels are wired to a controller which is connected to several large capacity batteries. Controllers are often called by other names, such as voltage regulator and solar regulator, but they perform the same task. They monitor voltage levels from the panels and batteries, and disconnect the panels when the voltages exceed preset limits. This prevents the batteries from draining back through the panels at night, and it also prevents the panels from overcharging the batteries during that day. The batteries are connected to the home switchboard through an inverter which increases the low battery voltage to mains power voltage, and changes the direct current to alternating current.
Before installing any residential solar power system, check with local authorities to see whether approval is required, and if the system needs to be installed by licensed contractors. The electricity company should also be asked about net metering, which allows excess power to be put back into the grid, effectively making the meter run backwards. Warranties must also be checked to ensure the system will last long enough to make back its cost. After the system has been installed, the only maintenance required is cleaning the glass on the panels, and replacing the batteries every few years.
While solar power systems can save a large proportion of home energy costs, further savings can be made by replacing outdoor features that uses mains power with solar powered versions. Lights with small panels can provide adequate lighting for most driveways and doorways, and solar fountains kits are available to fit most size ponds.
