Solar Thermal Case Study 2
4 Bed Cottage (170m²) - Retrofit
Location: Meath
Year built: 1800's, 1970's extension
Panel Area Installed: 6 m²
Panel Type: Flat Plate
Mounting: Integrated with Roof
The house has two occupants who run a business from their home. The system is designed for full occupancy corresponding to four people. This determined the size of both the collectors and the tank. Such an installation is expected to provide approximately 60% of the hot water over a given year.
As recommended by the installer, the flat plate collectors were integrated into the roof. The roof slates were stripped back and despite great care, there were some breakages due to the age of the slates. Access was by scaffold to the eave level and from there by roofing ladder. The picture above shows the collectors installed with the roof slates reinstated.
A 300lt glass-enamelled storage tank was installed. The tank design is of high quality and allows better stratification of the water in the cylinder. Insulation to a high standard was also included. Selection of the storage tank is crucial to the overall efficiency and effectiveness of the system in converting sun-light to hot water and in allowing the day's requirement to be built up without hindering the capturing performance of the collection system. The tank has two coils: The bottom connected to the solar collector system; and the upper connected to the central heating system.
Key Point: Careful consideration should be given to the location of the storage tank and how the tank is moved into position. Tanks of the type installed here require a clearance of at least 630mm. A straight stair does not normally present a difficulty, but stairs with return may do. For water heating only, the storage tank will fit in the hot-press, typically taking up one additional shelf space. It will weigh considerably more than the standard 120lt copper tank and so consideration may need to be given to its supports, particularly near stairwells. As the water tank is where your hot water spends most of its time, be aware that this is where the greatest losses of heat often occur.
All piping is rated for 150ºC and 6Barg Pressure, and insulated using Class 0 Armaflex® material. For safety, relief valves and anti-scald valves were also installed. A diaphragm tank is also installed to maintain a constant pressure in the system during normal operation. Pipe sizes of 20 to 25mm were used typically.
Flat panel installations can be expected to last up to 30 years or more. Typical installation costs for similar installations is of the order of €3,000 to €5,000, however to this may vary considerably depending on the situation.
System designed and installed by:
in partnership with Solar Energy North East 041 9823605
