Description
The demand for renewable energy has increased dramatically over the last 10 years. Therefore, the V-TAC has taken a step towards the distribution of photoelectric panels. The V-TAC will mainly focus on household systems.
What is a photoelectric panel and how does it work? picture). The principle of PV panels, as follows from the name, is the effect of photovoltaic cells (see Figure 2). This effect occurs when photons (solar energy) come into contact with silicon semiconductor and squeeze atoms from their usual trajectory. After this move, electrons and holes (positively and negatively charged particles) are released, thus creating a potential difference and current.
Photographic Panel consists of thin cells made of fragile material. They are placed on a base made of special material, the front is covered with glass and the entire structure is covered with an aluminum frame (see Figure 3). Separate module cells are connected to a string. Each cell has the attached nests to which it is connected to another cell, these sockets are pulled on the back of the panel in the so -called junction box. The panel positive and negative solar cables are also attached to this box.
Types of Photoelectric Panels.
The main types of photoelectric panels are 3. Monocrystalline, polycrystalline, thin film.
monocrystalline cells occupy the largest share of the market. They are most effective at 16-22%, but at the expense of their production is the most laborious, which in turn increases. Monocrystalline cells consist of one silicon crystal. To obtain this crystal, the Czochralski process is used in which silicon is melted in the bath in the vacuum environment (see Figure 4). The "germ" is submerged in the bath at the melted silicon and removed, and during removal, silicon is cooled to obtain a monocrystal silicon.
The crystal is then formed and cut into waffles (separate cells), the contacts are attached and the cell is ready for mounting on the panel.
polycrystalline cells occupy the second largest share of the market. Their efficiency is between 13 and 16%as they do not consist of one crystal. The production process is much cheaper than the production of monocrystalline elements, resulting in lower costs. The silicon is melted and poured into the molds, then cut into waffles, re -applied contact waffles and is ready for installation on the panel. By comparison, the classic silicon cells have a photo cell of 0.2 mm or 200 micrometers, while in thin -layer cells it is only a few micrometers. Depending on the technology, the thin-layer module prototypes have achieved 7-13% efficiency. The main ones operate about 9%. In the future, efficiency is expected to increase to about 10-16%.
Inverters
Inverter is a device that converts DC voltage or current to alternating voltages or current. Another name is DC/AC converter. Depending on the operating principle of the inverter, they are divided into two main groups inverters with built-in transformer and non -transformer inverters. Transformer inverters have 2-3% losses due to the presence of a transformer and are therefore used mainly in PV farms above 1MWP. In other cases, non-transformer inverters, which are approximately 98%, are used. In addition to operating principle, inverters are also divided into non -network and network connected.
in some inverters have a 50Hz generator built-in, so they are used in places where there is no network or not profitable to create it (see Figure 5)
Separate solar panels must have connected batteries.
The network connected inverters do not have a 50Hz generator. They take into account the shape and frequency of the external power supply, see Figure 6)
The main areas of inverter applications are:
- AC supply
- Excessive power supply of AC consumers
- supplied to the network electricity produced from photoelectric stations or other renewable sources
hybrid solar system
batteries. Where and why they are used.
Photoelia Power is irregular and cannot provide the necessary power for 24 hours a day, 365 days a year without interruption. Therefore, the energy generated by renewable energy should be stored to transfer it to the consumer if necessary. data-mce-fragment="1">-Lead-Acid (PB-Acid).
-Nickel Kadmium (NICD) .
-Lithium Joni (Li-ion).
-lithium polymer (li-poly).
Almost all PV, wind and hybrid backup power systems use lead-acid batteries for electricity storage (see 7 7 7 . Figure). This is mainly due to their low cost despite their lowest capacity to weight
Lead-Acid Battery Types. They are classified in two ways, depending on the intended use and construction (making). They are used in cars and for deep discharge (traction). Those designed for deep discharge are used for: photovoltaic or hybrid systems; emergency power systems; Caravans and boats. Deep discharge batteries are designed to provide 80% of their maximum energy and have thick electrode plates, unlike starter batteries with porous structure electrodes. The main types of lead acid batteries are liquid electrolyte, gel electrolyte or AGM (absorbed Glass Mat). AGM is known as batteries of dry elements because fiberglass is only 95% impregnated with acid without causing the risk of electrolyte splashing even if the battery is mechanically damaged.