What is a Rooftop Solar System? How does it work?

With the increasing electricity tariff and power cuts, there is huge demand for alternate energy options which the general public can rely on. With government easing the solar policy and providing subsidies, roof top solar solution has become the go to choice for people in India.

So before going for a roof top solar system lets know what is this all about!

What is a Solar Rooftop System?

A Rooftop photo-voltaic System, or Rooftop PV system, is a photo-voltaic system is a small scale solar power generation plant. In this kind of system, Solar PV panels are fixed on the available shadow free roof surface of residential or commercial buildings and connected to the main building electric power system.

When sun rays fall on these PV modules, they produce electricity which is fed to the main power junction box of the building to be used by consumer appliances.

A typical roof top solar system for homes consists of

  • Solar photo-voltaic panels or solar modules,
  • a strong mounting structure to hold the panels safely,
  • Solar inverter ,
  • Power conditioning unit or charge controllers
  • Batteries
  • Electric cables,
  • Circuit protection and surge protection devices.

Residential buildings can successfully accommodate a solar roof top system of capacity of about 1 to 10 kilowatts (kW),  which is more than sufficient for any house hold operation.

Commercial buildings such as office buildings or schools, colleges and  other non-residential buildings can install 100 kilowatts and more depending on the effective roof space available.

Types of Rooftop Solar systems

There are two types of rooftop solar systems for buildings.

A. Grid-connected Solar Rooftop system

B. Off-grid Solar Rooftop system

A. Grid-connected Solar Rooftop system

In a grid-connected roof top system, the solar system is connected to the local grid that supplies electricity to the building. In this system the electricity that is produced by the solar panels is consumed by the user and any residual electricity is fed back to the grid.

In on-grid/grid-connected solar system, there is no provision of batteries for storing the excess electricity generated. This is generally done to avoid any Islanding effect.( To avoid any back feeding of residual electricity to the grid or a portion of the circuit to avoid any accident during ongoing repair works)

These systems are relatively cheaper due to the lack of batteries, which are costly.

What it concludes is that, if you go for  a grid-connected solar system, then you can only use the electricity generated by the solar plant during the day time only. During night time and cloudy days you have to rely on grid supply.

B. Off-grid Solar Rooftop system

These systems basically have batteries as electricity storage units, the only extra items in the system and the system is not connected to the grid. So, even if the grid supply fails, you have electric supply. The use of batteries increase the overall cost of solar plants and require frequent maintenance.

So if you are opting for off-grid solar roof tops then ask your installers to provide you good maintenance free batteries.

Benefits of installing Solar Rooftop System

Solar roof top systems have many benefits. Lets check them out

  • There is no more dependence on the Grid. It generates electricity for your house or business during the long hours of grid failure. No more worries during grid failure and power cuts.
  • You cut down your monthly electricity bills by more than 70% and start saving.
  • Solar power generation is Environment friendly as there is no carbon di-oxide generation. You lower your carbon foot print. With less carbon in the air, you and your future generation generation will breathe cleaner air.
  • You become self-reliable.

The urban buildings in India provides a large amount of empty rooftop spaces and can inherently avoid the potential land use and environmental concerns when choosing a solar power plant option for their houses and  buildings.

Also India being positioned near equator receives ample amount of solar radiation through out the year, which makes rof top solar systems hugely successful.

Installing of roof top solar systems can be tricky. The second most important part of a solar roof top system is its mounting structure. Building with sloped roof will need a different mounting structure than a flat roof.

Like wise an On-grid solar power system will need different system design than a off-grid battery powered solar system. So, proper site assessment and designing is essential if you are planning for a solar roof top system for your home or office.

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