ROOF TOP SOLAR SYSTEM

Electricity generated through coal plants is becoming expensive by every passing day. Power cuts and increasing dependence on DG sets is causing a lot of damage to the environment. The demand supply gap for electricity is increasing in the country which makes it very important for people to start thinking of other ways of realizing their energy needs. Keeping this in mind Ministry of New and Renewable Energy (MNRE), Government of India is promoting off-grid solar PV systems under the Jawaharlal Nehru National Solar Mission in the country. Many people in the country have started feeling the need of installing solar PV system for their home, apartment complex or small office use, and with this article we would try to provide some information which can be a good starting point for a roof-top Solar PV system project.

Solar PV cell is the basic building block of a PV system. It consists of semiconductor material that absorbs sunlight to generate electricity through a phenomenon called “photoelectric effect”.  Only sunlight of a certain wavelength can effectively generate electricity. Although a solar PV can generate electricity on a cloudy day, but it is not as effective as it is on a sunny day.

A basic PV cell produces a very small amount of electricity and multiple of them are connected together to form a Solar PV module that can generate 10W to 300W output. If more electricity is required, them multiple such PV modules have to be installed in an array.

Multiple kinds of materials are used to create a solar cell and the efficiency of solar cell depends on the same. The efficiency of a solar cell is defined as its capability to convert a certain amount of sunlight into electricity. Solar cells available in the market are of various efficiencies: 4%, 8%, 12%, 14% and 16%. The size of a Solar PV module required will depend on output and efficiencies:

 Roof Area Needed in Sq. Ft.

PV Module Efficiency (%)	PV Capacity Rating (Watts)
	100	250	500	1,000	2,000	4,000	10,000
4	30	75	150	300	600	1,200	3,000
8	15	38	75	150	300	600	1,500
12	10	25	50	100	200	400	1,000
16	8	20	40	80	160	320	800

 

For example, to generate 2000 watts from a 12% efficient system, you need a 200 sq ft of roof area. (Source: solar PV sizing information on energysavers.gov)

Solar home lighting systems approved under NSM (National Solar Mission) are required to have a certain level of efficiency. The CFL based solar systems are required to have module efficiency of 14% and above and a LED based solar system is required to have module efficiency of 12% and above. Please note that such systems will have a serial number starting with NSM engraved on the frame.

Sizing a solar system

Before you buy a system, it is very important to size your solar system properly. Sizing will depend on the load requirements in your setup. It is important to note that a Solar system is good for operating low wattage appliances like lights, fans, TV, etc. High wattage appliances like Air Conditioners and Water Heaters cannot be operated using solar PV system (in fact solar water heaters and solar air conditioners are available separately). It is very important to make sure that your system is energy efficient so that you do need a bigger sized solar system.

Other considerations for installing a solar system

 Although a solar PV system can generate electricity through direct or scattered sunlight but it is very important to assess the amount of sunlight available at the location where a solar PV system is being installed. To collect maximum sunlight the ideal orientation of a Solar Panel is towards south.  However a 45-degree east or west of south can also work. The system should be placed in such a place so that there is no obstruction of trees or adjoining building. In case these requirements are not getting fulfilled, an expert should be hired to do a detailed analysis on the amount of sunlight available.

The load carrying capacity of the roof where the solar panels are to be installed should also be done. Solar Panel structure typically weight 15kg per sq meter and the roof should be able to handle the load.

Tilt at which the solar panel is installed is also an important consideration.

FOR MORE INFORMATION KINDLY CONTACT US BELOW!