PV FAQ's

So when it comes to owning a solar PV system, most individuals are not very educated when it comes to operation and maintenance protocols. Contractors or certified technicians thus briefly teach the homeowner(s) how to safely utilize and operate the system in case of any emergency situations. Whether you're a homeowner trying to understand how a PV system works, or a student interested in the solar field, here are some Frequently Asked Questions! Enjoy!


Q: What is photovoltaics?
A: Photovoltaics, or PV for short, is the direct conversion of solar energy to electricity, or the generation of "solar electricity". Photovoltaics is a well-established technology that many solar experts believe has the potential to satisfy a large part of our energy needs in the present and future.

Q: What is wrong with other current, usable sources of energy (natural gas, oil, petroleum, etc.) as compared to solar energy? 
A: Other sources of energy such as natural gas, oil, and nuclear fission at current consumption rates in the future will either become depleted, or very costly. They also cause problems such as harmful effects on the economy, rapid price increases, and environmental difficulties resulting from the operation of power-generating plants.

Q: What is energy? What is power?
A: Energy, including solar energy, may be used in many ways or converted from one form to another. Heat energy, mechanical energy, and electricity are all forms of energy with which we are familiar. Simply put, energy is that which is required to do work. However, many people confuse power and energy. While energy is that which is required to do work, power is the rate at which energy can be used or expended. For example, to raise an office safe to the second floor window requires the same amount of energy, whether it is raised quickly or slowly. But in order to raise it quickly, more power is required than if it were raised slowly.

Q: How is solar energy stored?
A: Storage methods may include the use of batteries, pumped water, compressed air, thermal hydrogen storage, flywheel generators, or superconducting magnets. However, in a residential grid-tied system, utility lines are usually readily accessible and may be more sensible to use as a back-up source, rather than installing a separate storage medium.

Q: What factors are taken into consideration for the assembly and design of a solar photovoltaic system?

Solmetric Suneye

A: In order to successfully determine the system design for a certain photovoltaic system, weather and insolation (shading) data are a major requirement. System size is determined not only by the amount of electricity required by the load, but also the amount of sunshine available to power the system. Other factors to consider include the planned tilt angle of the solar array, system accessibility, required hardware, and average monthly temperatures at which the photovoltaic array will operate most efficiently.

Q: What are the costs of a solar photovoltaic system?
A: The costs of a PV system include acquisition, procurement, operations, maintenance, and replacement. All of these costs are associated with a PV system over its lifetime; Add that with the time value of money, and then you have what is called life-cycle costing. If necessary, borrowing money to purchase an item may occur, thus the cost of the loan being incorporated into the total cost of the PV system.

Q: What would happen to a PV system array if it accumulated with inclement loads of rain or snow?
A: Prior to installation, structural laboratory engineers test the physical materials included in the construction of a PV system to withstand various snow, rain, and earthquake loads and forces. Rain would very likely clean the surface of the fixed glass on the outer layer of the PV module, but snow may build up onto the panels, blocking sunlight. However, a day or two of exposure to the sun would simply cause the snow buildup to slide off the surface of the glass.

                                                                     Q: What is the National Electric Code? 

A: The National Electric Code, or NEC for short, published by the National Fire Protection Association (NFPA), basically consists of a collection of regulations and codes that comply with safety considerations regarding electrical wiring methods, grounding, motor circuits, electrical safety, and efficient utilization. The NEC specifies sizes and types of switches, fuses, and wires to be used, as well as the location of where these certain items should be placed.

Q: Why do PV systems have to comply with the NEC?
A: NEC codes and components are necessary, not only to protect the end user, but also protect the maintenance technician. They also emphasize maximum efficiency and safe system execution.

Q: What is a string inverter? What is its use?
A: A PV inverter converts the direct current (DC) of a PV array into alternating current (AC) that complies with its utility/grid. It is fully automatic as soon as there is a reasonable amount of irradiance, feeding energy into the grid. It also displays and monitors performance and data levels.

Q: Where would my string inverter be located or mounted?
A: Inverters are designed to be mounted and installed both indoors and outdoors. If indoors, it should be known that the inverter's phases of operation may produce annoying, humming noises, thus leading to the reason that it should not be installed in a living, open area. Make sure to mount it on either a solid building surface, such as concrete, or on drywall to beams, or studs. Avoid areas with large clusters of dust, and steer clear of acids and salts. If installing outdoors, avoid sources of water such as sprinklers NEVER let it sit out in the sunlight, as an exposed string inverter under the sun will reduce the power output within operating limits. Install it in a protected location, such as near the solar panels, or under an area that's covered by the roof's overhang.

Sources
1) "Solar Electricity". Monegon Ltd. 1981
2) "Photovoltaic Systems Engineering". Roger Messenger & Jerry Ventre, CRC Press. 2000