Solar Panels

Solar panels are active solar devices that convert sunlight into electricity. They come in a variety of rectangular shapes and are usually installed in combination to produce electricity.

Solar Panels from GEM Energy Australia

Typical Solar Panels from GEM Energy Australia

Environmental Factors That Will affect the quantity of electrical Power produced

The amount of power solar panels produce is influenced by the amount of sunlight falling on your specific location per year, the efficiency of the underlying solar cell technology, the materials and technology used in making the solar panel, keeping your panels clean, and the amount of time the solar panel has been in use.When purchasing solar panels, it is therefore wise to look beyond size and look at the dollars/watt ratio. As solar project developers in Europe – we look more at the estimated kWh produced over the life of the solar panel … and calculate what our net return on investment will be.

Solar Inverters

An inverter’s basic function is to “invert” the direct current (DC) output into alternating current (AC). AC is the standard used by all commercial appliances, which is why many view inverters as the “gateway” between the photovoltaic (PV) system and the energy off-taker.

Central Inverters and Micro Inverters)

GEM Energy Inverters (Central and Micro Inverters)

A solar inverter, or PV inverter, or Solar converter, converts the variable direct current (DC) output of a photovoltaic (PV) solar panel into a utility frequency alternating current (AC) that can be fed into a commercial electrical grid or used by a local, off-grid electrical network.Inverters play a crucial role in any solar energy system and are often considered to be the brains of a project, whether it’s a 2-kW residential system or a 5-MW utility power plant.Solar inverters have special protection and grid support functions adapted for use with photovoltaic arrays, including maximum power point tracking and anti-islanding protection and a grid protection function where the inverter shuts down if the grid is blacked out. These functions are to protect the property, the inverter and the local grid.

 
Inverters are the most important part of any solar power system. If panels are the body, the inverters are the brains. Inverters can fail for a number of reasons, and if this happens can cost you considerable amounts of money through lost generation, if not identified early. The inverter also disconnects from the grid if frequency or voltage ranges fall outside of Australian standards.

How efficient is the conversion from DC to AC (and back again)?

A typical solar inverter is around 95% efficient, so you’ll only have about a 5% loss of power when the electricity is converted from DC to AC. The conversion from AC back to DC in your electronics is less efficient; you may lose 10-40% of the power.* That happens whether you’re using ordinary power from the grid or solar power– it’s just part of the way the system is set up. When you feel the black brick on your laptop cord getting hot, that’s a sign of a low-efficiency conversion of AC to DC.

Classification of Solar Inverters:

  • Stand-alone inverters, used in isolated systems where the inverter draws its DC energy from batteries charged by photovoltaic arrays. Many stand-alone inverters also incorporate integral battery chargersto replenish the battery from an AC source, when available. Normally these do not interface in any way with the utility grid, and as such, are not required to have anti-islanding protection.

Grid-tie inverters, which match phase with a utility-supplied sine wave. Grid-tie inverters are designed to shut down automatically upon loss of utility supply, for safety reasons. They do not provide backup power during utility outages.

Industrial Grid-tie Solar Inverter

Industrial Grid-tie Solar Inverter

  • Battery backup inverters are special inverters which are designed to draw energy from a battery, manage the battery charge via an on-board charger, and export excess energy to the utility grid. These inverters are capable of supplying AC energy to selected loads during a utility outage, and are required to have anti-islanding protection.
  • Solar Charge Controller

A charge controller may be used to power DC equipment with solar panels. The charge controller provides a regulated DC output and stores excess energy in a battery as well as monitoring the battery voltage to prevent under/over charging. More expensive units will also perform maximum power point tracking. An inverter can be connected to the output of a charge controller to drive AC loads.

A Typical Charge Controller Kit

A Typical Charge Controller Kit

Solar Isolators for Photovoltaic

Solar Isolators (SI) are switch gears for interrupting the DC/AC-Inverter from the solar-panels. Solar Isolators (SI) are switch gears for interrupting the DC/AC – Inverter from the solar panels. Photovoltaic – installations have to be equipped with DC – Isolators according to IEC 60364-7-712/ IEC 60947.

Switch Disconnectors (SI) ensure a reliable switching up to 32A with 1000V in the category DC21B. The construction of the contacts and the material selection guarantee that no oxidation (small switching frequency), and is thus prevented inadmissible heating-up. The switching speed at the manually operated handle does not have an effect on the switching attitude of the contacts.

Switch Disconnector

 

Photovoltaic Mounting Systems

Photovoltaic mounting systems are used to fix solar panels on surfaces like roofs, building facades, or the ground. These mounting systems enable retrofitting of solar panels on roofs or as part of the structure of the building (called BIPV).

Photovoltaic Mounting Systems

Roof mounting

The solar array of a PV system can be mounted on rooftops, generally with a few inches gap and parallel to the surface of the roof. If the rooftop is horizontal, the array is mounted with each panel aligned at an angle. If the panels are planned to be mounted before the construction of the roof, the roof can be designed accordingly by installing support brackets for the panels before the materials for the roof are installed. The installation of the solar panels can be undertaken by the crew responsible for installing the roof. If the roof is already constructed,

Roof mounting

Mounting as a shade structure

Solar panels can also be mounted as shade structures where the solar panels can provide shade instead of patio covers. The cost of such shading systems are generally different from standard patio covers, especially in cases where the entire shade required is provided by the panels. The support structure for the shading systems can be normal systems as the weight of a standard PV array is between 3 and 5 pounds/ft2.

Building-integrated photovoltaics

Building-integrated photovoltaics (BIPV) are photovoltaic materials that are used to replace conventional building materials in parts of the building envelope such as the roof, skylights, or facades. They are increasingly being incorporated into the construction of new buildings as a principal or ancillary source of electrical power, although existing buildings may be retrofitted with BIPV modules as well. The advantage of integrated photovoltaics over more common non-integrated systems is that the initial cost can be offset by reducing the amount spent on building materials and labour that would normally be used to construct the part of the building that the BIPV modules replace.

 

TYPICAL OFF-GRID SOLAR POWER SYSTEM INSTALLED

TYPICAL OFF-GRID SOLAR POWER SYSTEM INSTALLED

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