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Going solar? Everything you need to know

solar panels

In addition to reducing electricity bills, going solar presents many of the other benefits. What are solar panels, the principle of operation, manufacturing technology, characteristics, efficiency, as well as the structure of solar panels is something to know. I am sure you have a lot of questions if you are thinking about switching to solar energy. We will explain that the size of the solar system for one household depends on electricity consumption in the house itself. The example that will be given is an approximation for an average family. Solar power does not have to be complicated. It is enough to know the basics and boast of functioning. Of course, it should be not only environment-friendly but also affordable.

The situation is that you need to install a solar system, and of course, the first step you will take is to go to Google and start looking for answers to your questions. You have finally found a company that looks promising and, you start looking at products. After a few minutes, you realize that you still don’t know what you need and what the next step is that you should take. There is a period of frustration and often giving up on such a solution. Choosing the right solar system for your application is not a difficult process at all.

Solar cells

Solar cells are semiconductor structures that convert solar transmission, in a wide wavelength range, into electricity. The solar cell itself is composed of several diodes, p-n junction diodes, which operate in the fourth quadrant of the I-V output characteristic. Solar cells can be connected in series, in parallel, or their combination. It all depends on the projected power of the solar cell. The voltage obtained at the output depends only on the type of cell. The numbers are 0.3-0.7V, with a current density of about a few tens of mA/cm2 depending on the strength of solar radiation. 

The efficiency of a solar cell determines the production process; today’s commercially available modules are 3% to 17% efficient in converting solar energy into electricity. The solar cell itself is composed of particular semiconductor substances, such as silicon. Thanks to its chemical properties, silicon has many benefits, especially when it is in crystalline form. One silicon atom has 14 electrons, arranged in different layers. The first two layers are full with two and eight electrons. The third layer is only half-filled and holds four electrons. A silicon atom will always look for a way to fill the last layer, and to succeed in that, it will share electrons with four neighboring atoms.

Thus, the crystal structure turned out to be very important for this type of photovoltaic cell. When light, in the form of a photon, strikes a solar cell, the energy of that light separates pairs of electrons and voids. Then we have the electrons moving in a path to the P side to unite with the empty places that the electric field sent there. The movement of electrons creates a current, and the electric field of the cell causes a voltage. Power is a product of current and voltage.

Solar panels

Solar electric panels exist in all shapes and sizes, different materials. However, the most commonly used module is where solar cells make a sandwich. This so-called sandwich has 36 PV cells connected in series to produce enough voltage to charge a 12-volt battery. The purpose of the structure is to provide a rigid package and protect the intercellular connections from the environment. The location of plus (+) and minus (-) connectors on the back of the interconnection module. Modules can have an individual metal frame. Or they can be protected by a rubber seal. Four factors determine the performance of a solar electric panel: efficiency photovoltaic cells, load resistance, solar radiation, and cell temperature.

There are three major groups of photovoltaic systems:

  • On-grid systems connected to the public distribution network
  • Off-grid systems, which we also call autonomous systems because they are not connected to the public distribution network
  • Hybrid systems connected to some other source of electricity

There are several technologies used to make solar cells, building blocks of panels. Currently, the main types on the market are: 

  1. Monocrystalline solar panels are often the most expensive due to the manufacturing process, which uses large amounts of highly purified silicon and a large amount of energy. They are 15% efficient in converting solar cells light into electricity.
  2. Polycrystalline solar panels are slightly cheaper than monocrystalline. Their efficiency of cells ranges between 11-14%.
  3. Amorphous solar panels or thin-layer amorphous silicon are not made of individual cells. They use the photosensitive compound to the substrate. Their efficiency of cells ranges between 7-10%. 

CIGS technology or Copper Indium Gallium di-Selenide does not use silicone and can make panels with or without discrete cells.

There are also hybrid solar panels that use both crystal and thin-film augmentation technologies energy range (efficiency of up to 19%). The solar panels are coupled with and interact with a battery system. To keep higher output power, solar generators (solar cells) can be connected in series, in parallel, and in combination.  While a series connection increases the output voltage at the same current, a parallel connection achieves an increase in output currents. However, a combined connection increases both current and voltage. Unlike the current, the potential difference between the tiles does not depend on the surface of the tile. 

An example

Let’s suppose an average household has: a water heater, an electric stove, a refrigerator, a washing machine, a dishwasher, two TVs, two computers, about fifteen light bulbs. The largest consumers of electricity in the household are thermal users. For example, boilers and electric stoves are eating electricity. Right behind them are a washing machine and a refrigerator. TVs, computers, phone chargers are the smallest users of electricity.

In our calculations, we will assume that our devices have the following power:

Boiler 120l – 3000W
Electric stove – hob 1000W + oven 2000W
Fridge – 350W
Washing machine + a dishwasher – 3000W
TV – 100W +100W
Computer – 150W +150W
Bulb – 15W x 15W

Another important thing is that not every water heater consumes the same electricity, nor does every computer. You can find exactly how much each of your devices consumes on its back on the label with the specification (power expressed in W). Electric devices with energy label A +++ are the most energy-efficient devices that use the least electricity in their work. Followed by A ++ and A +, then A, then B, then C. Pay attention to this when buying home appliances; you can reduce electricity consumption. Everything you need to know (A-D) when you are going solar.

Everything you need to know (A-D) when you are going solar.

The calculation

The calculation is as follows: the power of each device is multiplied by the number of working hours during the day. And in the end, all the obtained values are added. It gives us how many kilowatt-hours (kWh) we spend per day. Everything you need to understand (know) basics about going solar calculation:  

Boiler: 3000W x 3h = 9000Wh

Electric stove: 1000W x 1h = 1000Wh

Electric oven: 2000W x 1h = 2000Wh

Refrigerator: 350W x 7h = 2450Wh (although the fridge works 24h, it effectively works much less, only when it reaches the required temperature again)

Washing machine: 3000W X 3h = 9000Wh

TV: 100W x 6h = 600Wh +600Wh

Computer: 150W x 5h = 750Wh+750Wh

Bulbs: 15W x 15pcs x 2x = 450W

When all this is added up, you get 9000Wh + 1000Wh + 2000Wh + 2450Wh + 9000Wh + 600Wh + 600 Wh+ 750Wh + 750Wh+ 450W = 26600Wh or 26.60kWh 

Analysis

One solar panel per day effectively works 4-5h, which is average. If we take one solar panel has a power of 250W times 4,5 h equals 1125Wh or 1,125kWh. It means that one solar panel per day produces 1125Wh or 1,125kWh. If we divide our daily electricity demand of 26.60kWh by the 1,125kWh delivered by one solar panel, we get that we need around 24 solar panels. One solar panel of 250W usually has two solar batteries of 100Ah each. Also, we need an inverter of, say, 5kW, which proved to be a satisfying choice for the average household and leaves room for a possible upgrade of the solar system.

 Of course, that is not everything you need to know about the calculation of going solar, but it is a start. As you can see, a lot of electricity consumption goes to the boiler. If you install a solar thermal water heating system, you will consume half as much electricity, and you will need half as many solar panels, so maybe ten or twelve pieces. If you use gas instead of an electric stove, you will save another 2000Wh per day, so five solar panels will satisfy your needs.

 Therefore, small modifications can significantly reduce electricity consumption and thus save the installation of a smaller solar system. You can see the complete offer of independent photovoltaic systems of the company on our website. You can also see the offers of solar thermal water heating systems on our website. As well as the recommendations and the experience of satisfied customers, or you can just ask for help

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