Based on the Photovoltaic (PV) Effect, photovoltaic devices generate power directly from sunlight. Such systems generate clean, dependable electricity without the need of fossil fuels and can be employed in a wide range of applications.
Albert Einstein, a famous physicist in the early twentieth century, understood the Photovoltaic Effect well in 1905. Solar cells are manufactured from silicon (e.g., sand) in a very sophisticated process, yielding solar cells that are then combined into solar panels.
For regular use in photovoltaic systems, solar cell efficiency ranges from 10 to 15%. In laboratory tests, the efficiency has reached 30%. PV panels produce direct current (DC) and low voltage (normally 12V) electricity. If possible, other system outputs can be explored.
The efficiency of a solar cell is defined as the ratio of output electric power to the quantity of power received from the sun. PV technology is utilized in a wide range of applications, including lighting, water pumping, telecommunication, refrigeration for health care, marine and air navigation, and other residential and commercial uses, as well as devices such as pocket calculators, watches, and so on.
Benefits of Photovoltaic Technology
Photovoltaic systems are a viable alternative to conventional power generating systems based on fossil fuels (e.g., diesel generator sets, kerosene lights, dry cell batteries).
Reliability
Photovoltaic systems have demonstrated their dependability even under difficult environmental circumstances. PV arrays provide stable power supply in situations where other technologies must operate continuously.
Durability
Even after 25 years of use, crystalline PV cells exhibit no degradation, but amorphous cells show degeneration after a few years. Future crystalline cells are anticipated to endure considerably longer. A reliable framing that protects the cells from damp and dust is critical for the long life of PV panels.
Low Operating Costs
It is costly to transport supplies and employees to remote places for equipment repair or service work. Because PV systems only require periodic inspection and minor maintenance, their costs are typically lower than those of traditionally fueled systems (such as diesel-powered generators). However, significant investment is required prior to the installation and operation of PV systems.
No fuel cost
There are no costs involved with purchasing, storing, or transporting fuel because no fuel source is necessary. However, batteries require maintenance and must be replaced every couple of years.
Independence
PV systems can function independently of national or local grids in remote places. However, due to the high investment costs, the energy service supplied is fairly limited when compared to grid connection or diesel gen sets, pushing the system size to be as modest as feasible. Insolation is the amount of solar radiation that falls on a specific region and is measured in Watts per square meter.
Components of a Photovoltaic System
Photovoltaic systems are made up of numerous parts:
PV Panel
A collection of PV cells placed between a glazing material and an encapsulating substrate that provides DC electricity at a 12 V output voltage in typical conditions.
PV System
A PV array is made up of many panels. The term module is sometimes used instead of panel.
Controller
It is also known as a charge controller, and it regulates battery charging and discharging.
Battery
A battery is a type of storage device that stores electrical energy (DC) as chemical energy.
DC Loads
Direct current (DC) loads are appliances (light bulbs, radios, televisions, fans, motors, refrigerators, etc.) that are powered by direct current.
AC Loads
AC loads are alternating current-powered appliances (light bulbs, radios, televisions, fans, motors, refrigerators, and so on).
Types of Photovoltaic Systems
Photovoltaic systems can be designed for a variety of purposes, including: Many household systems, for example, use battery storage to power appliances at night. Water pumping systems, on the other hand, frequently run just during the day and do not require an electrical storage device. A large commercial system would almost certainly include an inverter to supply AC appliances, whereas a modest solar household system [SHS] in a rural village would likely power just DC appliances and would not need an inverter. Some systems are connected to the grid, while others function autonomously.
Stand-alone System
All components, including the application (load), are included in a single package in these systems. A battery is an essential component of a system that can power loads at night or in overcast conditions. The batteries may power system loads during the day or night, continuously or sporadically, regardless of weather. Furthermore, a battery bank has the capacity to produce high-surge (high current) for a short period of time, allowing the system to start electric motors.
Batteries are one of the most delicate components of a SHS. They store solar energy in order to provide energy during times of low radiation (cloudy weather, at night). Charge controllers control batteries to prevent overcharging and deep draining, which would limit the battery’s life or perhaps damage it.
When the module is fully charged, a charge controller immediately disconnects it from the battery bank. Furthermore, charge controllers disconnect the load from the battery if it reaches the threshold of deep drain.