What is Solar Thermal?
Solar thermal is a clean and highly efficient means of using energy from the sun to heat the water used in the home. Normally the solar collectors are roof mounted and connected to a heat exchange coil at the bottom of your domestic hot water cylinder using a sealed plumbing circuit which contains antifreeze. There is a pump in the circuit which transfers the heat produced by the collector to the coil at the bottom of the cylinder, thus heating the entire cylinder.
How does Solar Thermal work?
The energy is received onto the panels (1) and heats a network of pipes using leading edge solar absorber technology
There is a temperature sensor attached to the collector pipes. The controller (4) reads the cylinder (2) and collector temperatures. When the temperature of the collector is approximately 7ºC higher than the bottom of the cylinder temperature the controller switches on the pump to bring the heat to the cylinder.
The pump transfers the heat from the collectors to the bottom coil of the cylinder through two ½” flow and return pipes carrying antifreeze.
When the collectors have cooled to approximately 4ºC difference the controller switches off the pump –allowing the collectors to increase in temperature again.
The whole process is repeated all day and is completely automatic.
If the solar has not produced enough hot water then your conventional heat source (oil/gas boiler, solid fuel or immersion) can be used to increase the water temperature.
Solar Collectors.
Solar Cylinder
Oil/Gas or solid fuel boiler
Solar station & controller.
End use, for example showers & sinks.
Why install Solar?
Solar thermal is the cleanest form of renewable energy; it is also economic, contributing up to 70% of the household’s hot water requirement per annum. Depending on your hot water demands and the primary fuel source a solar package has a payback period of approx 6 years. While this may seem a long time the useful life of the package should exceed 30 years.
New Buildings: Under the requirements of the Irish Building Regulation (TGD Part L 2007) there is a minimum level of renewable energy technology to be installed to ensure compliance.
Existing Buildings: With ever increasing evidence of climate change it is essential we reduce our carbon emissions and become less reliant on fossil fuel energy.
Quality Products
Our solar products are manufactured to ISO 9000 and ISO 14000 standards by leading edge German and Austrian solar producers. Our panels are tested by independent test laboratories to a range of standards including performance, water penetration, exposure to very hot & cold temperatures and high pressure. We are proud of the fact that our products have achieved Solar Keymark approval (The quality label for Solar Thermal products in Europe). Our panels are grant approved by Sustainable Energy Ireland for use in the Greener Homes Scheme.
Design for your Requirements.
We recommend 50 to 60 litres per person/day of hot water storage in your hotpress. As another rule of thumb we advise on 1m² of collector area for each 50 litres of hot water in the hotpress cylinder. Normally for a family of 5 we recommend 3 collectors and 300 litre hot water storage in the hotpress.
There are several factors to consider when designing the best performing installation:
Distance between the collectors and hot water cylinder.
Shading from buildings or trees.
Orientation of the collectors
Angle of collector inclination
Hot water demand
Size of your hotpress.
There are many factors influencing the energy levels received from the sun in Ireland, for example:
» Time of Day
» Time of the year
» Atmospheric Constituents ->Cloud Cover, Carbon Dioxides, Oxygen, Ozone and Water Vapour.
» Latitude of solar panel (Ireland is at 51º 50’), A solar panel at this angle, facing south, will receive most energy of the fixed solar panel variants.
» Obstructions (trees and buildings)
The following graph represents the energy levels received from the sun in 2006 (source: Met Eireann)
Solar Collector Orientation
In the northern hemisphere collectors should ideally face south. Surfaces which face south receive more radiation than surfaces with other orientations. However, orientations between 30º east and 40º west of south are acceptable and will not result in more than 10% loss in efficiency compared with the ideal southerly orientation.
Household Requirements
You can reduce your yearly domestic hot water energy costs by 60% - 70% with solar energy technology and a properly designed integration into other energy sources, this includes reducing your energy costs by 80%-90% in the summer time and reducing your energy costs by 30- 40% in the wintertime. One can use the available solar energy even better, when showers, washing machines and dishwashers with Domestic Hot Water (DHW) connections are routed to the solar heated water tank (Be careful with low temperature washes!).
Passive solar design
The cheapest form of capturing the sun’s energy and is achieved by designing buildings and fixing their orientations to achieve maximum exposure to the sun, i.e. glass facades and building facing south. The benefits are for the life of the building.
Active solar heating
Active solar collectors transform solar radiation into heat and transfer that heat to a medium (water, solar fluid, or air). Then solar heat can be used for heating water, to back up heating systems or for heating swimming pools.
Flat-plate Collectors
A flat-plate collector consists of an absorber, a transparent cover, a frame, and insulation. Usually an iron-poor solar safety glass is used as a transparent cover, as it transmits a great amount of the short-wave light spectrum.
