Photovoltaic (PV) Cells - commonly known as solar cells, are semiconductor devices that convert sunlight into electrical energy.
Photovoltaic (PV) Cells typically made of semiconductor materials like silicon (2nd most abundant element on earth) or other compound semiconductor such as cadmium telluride (CdTe) or copper indium gallium selenide (CIGS)
Photovoltaic Effect - - involves the generation of an electric current when certain materials are exposed to sunlight. This effect occurs due to the interaction between photons (light particles) and electrons in the material.
Solar Radiation - often called the solar source or just sunlight is a general term for the electromagnetic radiation emitted by the sun.
Direct Radiation - made up of beams of light that are not reflected or scattered, which is the surface in the straight line from the sun.
Diffuse Radiation - the radiation scatter towards the receiver, coming from the whole sky apart from the sun disc
Albedo Radiation - radiation reflected from the ground
Global Radiation - The total radiation falling on a surface is the sum of this (direct + diffuse + albedo).
Irradiance - density of power falling on a surface and measured in W/m2
Irradiation - n density of the energy that falls on the surface over some period of time and is measured in Wh/m2
Global Horizontal Irradiance - the total solar radiation incident on a horizontal surface, measured in W/m2.
Global Horizontal Irradiance (GHI) - directly proportional to the power potential.
Sun Path
refers to the seasonal and hourly changes of the sun as the Earth rotates and orbits the sun.
A key concept to understand both when designing a solar electric system, and when trying to understand the performance of a solar electric system.
Sun Path Events:
equinox
solstice
Azimuth - The direction of the magnetic field at a point on the surface of the earth. Direction where our solar is facing.
Solar Window - It is between 9 AM and 3 PM that we receive the maximum energy from the sun. To harness the maximum possible energy at the given geographic location, the solar window should be clear or not be shaded by trees or any other obstacles.
Components of PV Panel
Solar Cell
PV Module
PV Panel
Solar Cell Stringing - The process of connecting solar cells together to form a string.
Panels are made up of solar cells most commonly 60 cells. This cells are connected in series, with three bypass diodes installed on each substring of 20 cells.
Bypass Diodes
An activated diode that will cut off the entire substring which is 20 of the 60 cells on a conventional panel.
Fabrication of PV Modules
soda-lime glass
solar cells
back layer
frame
junction box
Solar cells are sandwiched in between 2 layers of encapsulants (EVA - Ethylene vinyl acetate)
Junction box - where the generated electric current stores.
Laminating - one of the most important steps during module production
Balance of System (BOS)
PV Modules
Inverter
Charge Controller
PV modules - converts sunlight instantly into DC electric power.
Inverter - converts DC power into standard AC power for use in the home.
Charge controller - prevent battery from overcharging and prolongs the battery life of your PV system.
Battery
stores energy when there is an excess coming in and distributes it back out when there is a demand.
Less advantage if we have a steady source of energy (ex. meralco).
Utility Meter - utility power is automatically provided at night and during the day when the demand exceeds your solar electric power production.
Types of PV System
Grid-tie System
Off-grid System
Hybrid System
Grid-Tie System
grid connected or utility-intertie PV systems are designed to operate in parallel with and interconnected with the electric utility grid.
Off-Grid System
Standalone System
this PV systems are designed to operate independent of the electric utility grid