A key consideration in the overall performance of any PV system is how the installed system can use the sun’s energy most effectively. For the array to perform at its best, you need to install it so that it has access to as much energy as possible. Because sunlight is the “fuel” for any PV array, …
Understanding Solar Radiation for PV Installlation Read More »
One of, if not the, most exciting portions of the overall system installation process is the site survey. Why? Because you get to work with a blank slate (after all, the client shouldn’t have another PV system anywhere on his building or property) and create a PV system from the ground (or roof) up. As the person who performs the site survey, you need to be able to identify any potential trouble …
Sizing a Battery-Based PV System In addition to grid-direct PV systems, which I show you how to size in privious article, the other major PV system type you’ll likely have the opportunity to design and install is a battery-based system. You can install one of these systems on the grid (utility-interactive) or off the grid (stand-alone). …
Sizing a Grid-Direct PV System When you set off on the task of sizing a grid-direct PV system you need to account for many variables. As you find out in this article, the overall process results in a PV system that’s based on the client’s budget, the available area, the annual energy production and consumption …
PV Arry Charge Controllers Charge controllers are used to control the current coming from a power source. The charge controllers that are commercially available come in a variety of sizes and have an assortment of features. Small charge controllers can be used in very small systems with one or two PV modules charging a small battery bank. Larger …
Standard Test Conditions for PV Modules PV modules have to undergo some very stringent tests and certifications before they ever reach the consumer (or the installer, for that matter). An Underwriters Laboratory (UL) test protocol, UL1703, covers PV modules and requires testing of both the electrical and mechanical portions of each and every PV module. …
JFET Construction and Working The junction field-effect transistor (JFET) is a three element electronic device. Its operation is based on the conduction of current carriers through a single piece of semiconductor material. This piece of material is called the channel. An additional piece of semiconductor material is diffused into the channel. This element is called …
Power MOSFET Construction and Working Metal-oxide semiconductor field-effect transistors (MOSFETs) are a rather new addition to the unipolar transistor family. A distinguishing feature of this device is its gate construction. The gate is, for example, completely insulated from the channel. Voltage applied to the gate will cause it to develop an electrostatic charge. No current …
Light Sensitive Devices Light-sensitive devices include photo cells, solar cells, photo-diodes, and photo-transistors. Photo Cell It is a light-sensitive device in which the internal resistance changes with a change in light intensity. The resistance change is not proportional to the light striking it. The photo cell is made from light-sensitive material such as cadmium sulfide …
Electrical Specifications of PV Modules PV modules have the ability to produce power, and each module has its own specific current and voltage characteristics. You can find all of these specifications listed on the backside of every module you buy as well as on every specification (spec) sheet from the manufacturers. The power value is important because …
