Solar Panels
Introduction
The use of Solar Energy has increased significantly in both the residential and commercial sectors in Ireland and the UK over the last decade. There are 2 main categories of solar panels which use completely different technologies to make the most of the energy from the sun:
- Solar Water Heating Collectors: These panels absorb the energy from the sun and transfer it to heat water.
- Photovoltaic or Solar Electric Panels: These transform solar radiation directly into electricity, which can then be used throughout the building.
In this section of our website, we will be focusing on the first category of Solar Panels i.e. Solar Water Heating Collectors or Solar Thermal Panels.
Solar Thermal Panels
Solar water heating systems are the most popular form of solar energy used in both Ireland and the UK. The system is typically connected to a dual coil hot water cylinder (where only hot water is required) and to a large buffer tank (or alternate system) where space heating is also required. Solar water heating systems can provide around 70% of a household's hot water requirements during the course of the year. During the coldest winter months, your solar system may only provide 20-25% of your hot water needs, however, during the summer months, up to 100% of your household’s hot water needs can be provided for, by your solar thermal system.
In a household that spends around 25% of its electricity bill on hot water heating, the cost of a Solar Panel installation could be recouped in as quickly as 5-6 years of reduced bills. Given that a Solar Panel installation could last up to 20-25 years, customers would be expected to make considerable savings during the life-time of their system.
The two main types of Solar Thermal Panel available: 1) Flat Plate, and 2) Evacuated Tube. These are described in greater detail in the Technology section on this page.
In the Quote section below, customers can choose between Flat Plate and Evacuated Tube Solar Panels (or select “All”), indicate the number of residents in the household, enter county details and select their preferred Sort option, before viewing a list of products tailored to their criteria.
Roof Orientation and Panel Placement
To ensure maximum efficiency, solar panels should ideally be mounted on a south / south-east / south-west facing roof, away from any shadows from trees, surrounding buildings or chimneys. This enables the panels to receive as much direct solar radiation as possible. Solar panels will also work on east or west facing roofs; however, a larger area of solar panels may be required to compensate for the reduced level of sunlight.
With regard to the angle of installation, the Solar Collector / Panel will be most effective when the angle of the sun is at right angles with the plane of the collector. However, the solar angle changes throughout the day and the year. On average, the optimum inclination angle for solar panels in the United Kingdom and Ireland is around 30-40 degrees, which fortunately, is also the normal pitch of a roof in this part of Europe.
Grants of up to €300 per sq. m available
Sustainable Energy Ireland (SEI) is promoting the use of solar panels in the Residential market via a range of grants available through the Greener Homes Scheme (Phase 2). This has contributed to a significant increase in demand in this sector in recent years, and it is expected that this trend will continue over the coming years. The following grants are available for solar panels for Hot Water and Space Heating:
- €300 / Square Metre for Evacuated Tube Solar Panels, to a maximum of 6 M˛ or €1,800
- €250 / Square Metre for Flat Plate Solar Panels, to a maximum of 6 M˛ or €1,500
Solar Panel Technology
Flat Plate Solar Panels are what first comes to mind when you think of solar panels. The original Solar Panels were Flat Plate systems, consisting of an absorber plate behind which runs a copper piping structure containing glycol. Once this heats up the thermal energy is transferred via a Heat Exchanger. Technological advances continue to be made with Flat Plate Solar systems and they have the advantage of being robust, reliable, require minimal maintenance and are frequently supplied with 10 year manufacturer warranties.
Evacuated Tube Solar Panels tend to be more efficient than Flat Plate Solar Panels (around 90%, depending on the manufacturer, compared to around 80% for Flat Plate) which means that you need a smaller area of Panel to achieve the same level of heat output. This is really only a factor if there is a limited roof area available, onto which the solar panels are to be fitted. From a cost perspective, a slightly smaller area of Evacuated Tube panels will probably cost the same as a slightly larger area of Flat Plate solar panels.
Photovoltaic (Solar Electric) Panels
Photovoltaic (PV) or solar electric offers the ability to generate electricity in a clean, quiet and renewable way. Photovoltaic panels are frequently used to provide lighting for seasonal holiday homes, garages or outhouses. A wide variety of applications also use solar electricity. Photovoltaic cells are used not only in simple applications such as calculators and watches, but also to power larger, domestic applications such as radios or domestic drills.
