Understanding Solar
Understanding Solar
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Solar Panel Types
Solar panels that produce hot water are known as solar thermal collectors (and won’t qualify for a grant); solar panels that produce electricity are known as photovoltaic (and are supported by grants).
Solar Photovoltaics (Solar PV) come in three main types: thin film PV panels, mono-crystalline, and polycrystalline PV panels.
Thin film panels
Thin film solar panels consist of a thin layer of semiconductor material on another surface made of either glass, plastic, or metal. They are incredibly thin, making them flexible and lightweight.
Currently the average lifespan of these panels is 10 years.
Mono-crystalline (MC) panels
Those are the most effective and efficient solar panels but also the most expensive. Mono-crystalline panels are made from a large number of small silicon crystals.
Many MC panels fitted also use a new technology called PERC Technology (Passive Emitter and Rear Cell) designed to capture reflected light at the rear of the panel to improve efficiency.
Poly-crystalline (PC) solar panels
Polycrystalline PV panels are formulated by melting together several fragments of silicon rather than a single silicon crystal as in the case of mono-crystalline. They are cheaper to produce but also less efficient then MC panels.
Both MC and PC panels have a lifespan of around 20 years.
Additional Hardware
n addition to the actual panels, a solar set-up needs at least two more component, an inverter and a systems disconnect.
Inverter
Solar panels generate a direct current which needs to be converted into alternating current to be used around your home. The inverter does that.
Inverters come in two different forms: string inverters and microinverters. A string inverter is mounted to the side of your home, and it collects all of the electricity generated by your system in one place. Microinverters are small components that are attached to the underside of each individual solar panel and convert the electricity directly at the panel.
Solar Power Systems Disconnects
Solar power system disconnects are the electrical switch that controls your system. The system disconnect allows you to cut off the power output from your solar array. You may need to do this from time to time to accommodate repairs and maintenance.
Optional components for a solar system are battery & charge controller and a solar power meter.
Battery & Charge Controller
Any electricity your solar system produces which is not being used straight away is lost. To avoid this waste of energy any surplus can either be exported into the grid (see microgeneration) or stored in a battery which comes with a charge controller, a device that manages the flow of electricity from your solar panels to the battery and ensures the battery is charged to an optimal level to preserve the longevity of the battery.
Solar Power Meter
Another optional component is a solar power meter, which allows you to monitor how much solar power your panels produce. This helps you understand and monitor the performance of your system and adjust the system and your usage to the changing conditions throughout the year. A solar power meter is also vital if you export electricity into the grid.
Solar Effectiveness
Modern solar panels only need daylight to produce electricity and/or heat your water though they are more efficient when the sun shines.
In Ireland unfortunately the energy they produce fluctuates considerably over the year: In summer with long daylight hours solar panels can provide 100% of the energy needed for an average household and even a surplus. In winter however with very short daylight hours this can go down as low as 25%.
A back-up, either in the form of batteries, generator, supply from the grid or combination of those, is recommended.
Solar PV systems are rated in kW. A 1kW system would need 3 or 4 solar panels. To supply an average Irish home with electricity a 2kW system is needed. Any surplus electricity can be stored in a battery or exported into the grid.
The efficiency of a solar PV system relies on three main factors:
The amount of electricity you use
The time of day you are at home and use electricity (storage options are somewhat limited or very expensive)
Orientation of your roof (south facing roofs are best suited for solar panels)
More information on solar energy is available here: https://www.seai.ie/technologies/solar-energy/
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