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Solar FAQ's
You've probably seen calculators that have solar cells -- calculators that never need batteries, and in some cases don't even have an off button. As long as you have enough light, they seem to work forever. You may have seen larger solar panels -- on emergency road signs or call boxes, on buoys, even in parking lots to power lights. Although these larger panels aren't as common as solar powered calculators, they're out there, and not that hard to spot if you know where to look. There are solar cell arrays on satellites, where they are used to power the electrical systems. You have probably also been hearing about the "solar revolution" for the last 20 years -- the idea that one day we will all use free electricity from the sun. This is a seductive promise: On a bright, sunny day, the sun shines approximately 1,000 watts of energy per square meter of the planet's surface, and if we could collect all of that energy we could easily power our homes and offices for free.
Solar Energy may seem puzzling to some people that are not familiar with it. To help those of you that are being exposed to solar power for the first time, we have compiled and answered a dozen of the most frequently asked questions that we commonly hear at McSOL (PVT) LTD.We hope this FAQ file is helpful to you.
1. How does solar power work?
Solar modules (also known as photovoltaic or PV modules) convert solar radiation into electrical energy. Solar cells use daylight to generate a DC output which is stored in a battery bank. This stored energy is converted to AC power (220V/50Hz or 110V/60Hz) by an inverter and fed into the load at the home, factory, office, or farmhouse.
2. How is the solar energy system connected to the electrical system in a building?
The output of the battery is connected via an inverter which provides AC power (220V/50Hz or 110V/60Hz). This can be connected to the main panel board of the building or a separate distribution board may be installed that controls the circuits that are to be powered by solar energy.
3. What components do I need for an off-grid system?
There are many components that make up a complete solar system, but the 4 main items on a stand-alone system are: solar modules, charge controller(s), battery(s) and inverter(s).The solar modules are physically mounted on a mount structure and the DC power they produce is wired through a charge controller before it goes on to the battery bank where it is stored. The two main functions of a charge controller are to prevent the battery from being overcharged and eliminate any reverse current flow from the batteries back to the solar modules at night. The battery bank stores the energy produced by the solar array during the day for use at anytime of the day or night. Batteries come in many sizes and grades. The inverter takes the DC energy stored in the battery bank and inverts it to 240 VAC to run your AC appliances.
4. Can I use all normal 240 VAC appliances?
Yes but with energy efficiency in mind. When you purchase and install a renewable energy system for your home, you become your own power company, so every kWh of energy you use means more equipment (and hence more money) is required to meet your energy needs. Any appliance that operates at 240 VAC (such as electric water heaters, iron, microwave and air conditioners) is expensive loads to run on solar. We recommend the use of solar energy for refrigeration, TV, lighting, and fans. The rule of thumb in the renewable energy industry is that for every Rupee you spend replacing your inefficient appliances; you will save three Rupees in the cost of a renewable energy system to run them. So you can see that energy conservation is crucial and can really pay off.
5. What type of solar module mounting structure should I use?
The simplest mount is a roof/ground based frame angled toward the sun. A step up is a raised mount that has an adjustable angle to allow for the changing angle of the sun in the sky through-out the year at top or side-of-pole. The most efficient (and most expensive) is a tracking mount that follows the sun in its arc across the sky each day
6. What roof size is required to make a photovoltaic system viable?
A photovoltaic system with a nominal output of 1,000 Watt (1 KWP) requires approx. 9 m² of roof surface area. The size of the solar energy system should be adapted to suit the size of the suitable roof area.
7. How many Solar Panels will I need?
This will depend on the amount of energy in watts that your appliances use.
8. How much Solar Panels do expect Lifespan?
They are quite durable & you can expect 25 years or more of service.
9. How high are the operating and maintenance costs?
Photovoltaic systems require almost no maintenance. Consequently the operating and maintenance costs are very low. Dust and dirt are usually washed away by the rain. It is advisable that the user should remove any significant accumulation of dirt from the solar panels, e.g. leaves, dust particles.
10. Is the system 1-phase or 3-phase?
Normally we would quote for 1-phase systems. However, we can also provide 3-phase systems as well if required. Most industrial applications would require 3-phase loads. However, for urban applications, there is no need to use 3-phase systems since almost all loads are 1-phase.
11. Why do I need a Charge Controller?
A charge controller regulates the charge on the batteries, giving full power when necessary and reducing the charge as the batteries require less. This is important for maintaining the health of the batteries
12. What's the difference between a true sine wave inverter and a modified sine wave inverter?
The AC sine wave of a true sine wave inverter is just as good as the utility company's AC power. A modified sine wave inverter is not as close, but is still quite satisfactory in most cases. Certain motor control circuits don't like the modified wave. Modified sine wave inverters are also much less expensive.
13. Can I use normal car batteries (lead acid type) with the solar system?
It is not recommended that car batteries be used for solar applications. The best option is to use VRLA – AGM type Deep Cycle batteries, which are sealed and maintenance free. These also allow for longer life (5-10 years) and are able to sustain heavier loads. These VRLA Deep Cycle batteries also allow for discharge up to 60% against 20% for the car batteries.
14. Do I need planning permission from the municipality or other agencies?
In most cases, planning permission is not required when installing a photovoltaic system on a roof
15. What are photovoltaic peak watts?
The maximum rated output of a photovoltaic device, such as a solar cell or array, under standardized test conditions, usually 1000 watts per square meter (0.645 watts per square inch) of sunlight with other conditions, such as temperature specified. Typical rating conditions are 68°F (20°C), ambient air temperature, and 1 m/s (6.2 x 10-3 miles/sec.) wind speed.