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Showing posts from September, 2013

lesson04 - MPPT Solar Charge Controller

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 MPPT Solar Charge Controller What is MPPT? MPPT or Maximum Power Point Tracking is algorithm that included in charge controllers used for extracting maximum available power from PV module under certain conditions. The voltage at which PV module can produce maximum power is called ‘maximum power point’ (or peak power voltage). Maximum power varies with solar radiation, ambient temperature and solar cell  temperature. As the graphs in figure, we see that at the different solar radiations, PV modules deliver the variations in parameters as follows: (1) Maximum power; Pm (2) Maximum power voltage; Vpm (3) Open circuit voltage; Voc (4) Maximum power current; Ipm (5) Short circuit current; Isc MPPT solar charge controller A MPPT  solar charge controller  is the charge controller embedded with MPPT algorithm to maximize the amount of current going into the battery from PV module. MPPT is DC to DC converter which operates by taking DC i...

lesson03 - How PV Cells Work

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A typical silicon PV cell is composed of a thin wafer consisting of an ultra-thin layer of phosphorus-doped (N-type) silicon on top of a thicker layer of boron-doped (P-type) silicon.  When sunlight strikes the surface of a PV cell, this electrical field provides momentum and direction to light-stimulated electrons, resulting in a flow of current when the solar cell is connected to an electrical load.  a typical silicon PV cell produces about 0.5 – 0.6 volt DC under open-circuit, no-load conditions. The current (and power) output of a PV cell depends on its efficiency and size (surface area), and is proportional to the intensity of sunlight striking the surface of the cell. Solar PV system Solar cells  produce direct current (DC), therefore they are only used for DC equipments. If alternating current (AC) is needed for AC equipments or backup energy is needed,  solar photovoltaic  systems require other components in addition to solar modules. These componen...

lesson02 - Photovoltaics (PV) System Basics

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Basics of Current Current is classified into two types: • Direct Current (DC): DC is unidirectional flow of electric charge that means its direction remains constant. Examples of DC power source are battery and solar cell, etc. Direct Current or DC is suitable for using with DC appliances not to reverse polarity. • Alternative Current (AC): AC is an electric current which direction reverses cyclically. The usual waveform of AC power is sine wave with frequency 50 or 60 Hz. Examples of AC power sources are utility power supplies to residences and businesses, audio and radio signals, etc. What is Electricity? Any appliances that we use in our daily lives such as household appliances, office equipment and industrial equipment  almost all of those things take electricity. Therefore, we should understand electricity. What is Current? An electrical phenomenon is caused by flow of free electrons from one atom to another.  What is voltag...

lesson01 - Energy Use in the Home

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Energy Use in the Home Introduction Energy from the sun can be tapped to provide a clean source of home energy. This lesson will introduce you to the ways we use energy in the home, and how solar energy can be used to meet some, or all, of a home’s energy needs. It will also address safety, codes and covenants, and permits for Pennsylvania. Energy Efficiency First Installing energy-efficient systems in a home is more cost-effective than meeting the energy needs of less-efficient equipment with solar energy. Reducing electricity use is the best and least expensive way to save energy and money. Using Solar Energy in the Home Solar energy —energy from the sun—can provide the energy needed for many of these uses. In fact, solar energy can provide all the energy needs in a home. However, systems designed to meet all energy loads in a home are larger and thus expensive. Zero-energy homes  are both energy-efficient and capable of producing enough of their own ...