Solar panels

The photovoltaic solar panels in these images can charge 12V batteries at more than 9 amps under the direct sun.

We all know that it is possible to convert solar energy into electrical energy by using solar cells grouped in panels solar photovoltaic.

A solar panel is a module that brings together a varied number of solar cells that harness the energy of solar radiation. The term includes the solar collectors used to produce hot water (usually domestic) and the < a href="http://www.daprose.com/energy/solar_panels.htm">photovoltaic panels used to generate electricity.

For the planning, construction and installation of solar panels, get our Graphic, Practical and Illustrated Guide to Building Low Cost Solar Panels. Click Here

Photovoltaic panels

Photovoltaic panels are made up of numerous cells that convert light into electricity. The cells are sometimes called photovoltaic cells, from the Greek “photos“, light. These cells depend on the photovoltaic effect by which light energy produces positive and negative charges in two neighboring semiconductors of different types, thus producing an electric field capable of generating a current.

Photovoltaic panels, in addition to producing energy that can feed a terrestrial electrical network, can be used in electric vehicles and solar boats or yachts. The best of these techniques come together in competitions such as the Solar Splash^[1] in North America, or the Frisian Nuon Solar Challenge^[2] in Europe.
The most important problem with photovoltaic panels is the high cost. The price of silicon used for most panels is now trending higher. This has caused manufacturers to start using other materials and thinner silicon panels to lower production costs.

Due to economies of scale, solar panels become less expensive as more customers are used and more panels are manufactured. As production is increased, prices will continue to fall, and that is what is expected in the coming years.
The fastest growing area is made up of systems connected to the public grid (grid tied systems). In the United States, with incentives from the states, the power companies, and (in 2006 and 2007) the federal government, growth has continued and will continue.
The “net metering programs” (net metering) allow users to receive compensation for any extra energy added to the network . Most of this system buys the energy at the same sale price, although some companies buy it at a price close to 1/3 of what they charge.
In contrast, in Germany an extreme net-metering system has been adopted to encourage the growth of the renewable energy market, so that you pay eight times what the company charges strong>. This high incentive has created a huge demand for solar panels in that country.

Solar hot water

One laundry of clothes in California, EE. USA, with solar hot water panels on the roof.

A solar water heater uses the sun’s energy to heat a liquid, which transfers the heat to a heat storage compartment. In a house, for example, domestic hot water can be heated and stored in a hot water tank.
The panels have a receiving plate and tubes through which liquid circulates adhered to it. The receiver (generally covered with a dark selective layer) ensures the transformation of solar radiation into heat, while the liquid that circulates through the tubes transports the heat to where it can be used or stored. The heated liquid is pumped into an energy exchanger device (a coil inside the storage compartment or an external device) where it leaves the heat and then circulates back to the panel to be reheated. This provides a simple and effective way to transfer and transform solar energy.

Price of photovoltaic solar panels

The price of photovoltaic panels has not changed significantly since 2005, since the wholesale price ranges from $4 to $6 USD per watt. As the amount of production increases, prices will probably continue to decline as well. Thus, a 60-watt panel could cost $240 to $360 wholesale (1,000+ panels per order) and $300 to $420 retail, depending on quality, manufacturer, warranty, and distance from the panel. manufactures it to the consumer.
Retail prices, that is, orders of less than 1000 panels, used for small systems such as those used in homes and large and small establishments, are around $6 to $10 USD per watt. For example, a 60W panel could cost anywhere from $360 to $600 USD each panel. And between $17 to $25 USD for each watt already installed.

Depending on the consumption habit of each person and the size of the building to install these panels, a house usually needs from 20, 25, 30, 35, 40 or more panels of 60W each, although there are up to 240W each, being able to thus use fewer panels, and are of course somewhat more expensive. The equation is very simple, for each 240W panel, 4 60W panels would be needed, which implies more space for the panels and more labor for manufacturing and installation. I personally prefer the 240W ones. The reason is very simple, I get more power, they take up less space, and I have to make or buy fewer panels.
Another alternative is to build these panels yourself. For the planning, construction and installation of solar panels, get our Graphic, Practical and Illustrated Guide to Building Low Cost Solar Panels. Click Here

How many panels do I need for my house?

The first point to take into account is your good habits of use of electricity. All incandescent bulbs will need to be replaced with energy efficient bulbs “before” even thinking about using a solar power system.
Energy saving light bulbs consume an average of 75% less electricity than incandescent light bulbs. Also, there are appliances that by their nature consume a lot of electricity and must be rationed in their use, such as air conditioning, microwave ovens, appliances that operate with electrical resistance such as toasters, irons, hair dryers, etc.
A simple way to calculate the number of photovoltaic panels needed for your home is with your last electricity bill. Look on your receipt for the number that indicates the average daily consumption in kWh. Multiply this number by 1,000 and then divide the result by the daily average hours of sunshine (let’s say it’s 10 hours of sunshine per day). Example: if the number you found is 9.13 kWh then:
9.13 x 1000 = 9,130 ​​/ 10 = 913 watts
Finally, divide this last number by the number of Watts generated by each solar panel, in this case, each panel is 60 watts:
913 / 60 = 15.2 panels.

In summary, if your average daily consumption is 9.13 kWh, you need 15 solar panels to provide your house with electricity. But of course, this is for a person who consumes almost no electricity. In the US the average kWh per day usually ranges from 30 to 200 kWh per day, which drives up the cost of panels and installation considerably.
The good news is that you can create a scalable solar energy system, that is, you can start with a small system of 4 solar panels and increase the number of these, month after month, or year after year, until you reach the desired wattage. .
This is achieved thanks to the use of solar inverters that connect directly to the existing electricity line of your house or office. For each set of 4 panels, you will require a solar inverter of 250 watts.
With solar panels properly installed, in a shade-free area, and connected to one or more solar inverters, you will be able to run your electricity meter backwards during the day when you are generating more electricity than you consume. At night, your meter will work normally (forward). Basically, during the day this solar system provides electricity to the electricity company, which is returned to you at night.