Solar thermal installation, Dr Burrows, Boars Hill Oxford
Dr Burrows approached Heelas heating to install a solar thermal system (solar hot water) to his house In Boars Hill. Dr Burrows had a challenging roof layout which needed careful planning due to a roof valley, Velux rooflights and a large chimney. The roof dimensions and solar panel position were carefully measured and verified before the quotation was given.
Heelas heating always specify a proper tubular scaffold which is normally erected a week prior to the job commencing. Health and safety guidelines can only be properly met with the use of a full scaffold and safety handrails which project up to the ridge of the roof.
A 58mm Solar evacuated tube set was installed on the South facing elevation of a valley. In our experience we have found that the evacuated tubes work much more efficiently than flat plate panels. Evacuated tubes given much better performance during the autumn, winter and spring periods due to their design. On a sunny winter's day when the air temperature maybe below freezing, evacuated tubes can still give you a very good temperature rise to your hot water cylinder. This is due to the collector plates being inside a vacuum filled tube, where heat/sunlight can get in to the tube, but it cannot escape. Flat plate collectors work equally as well in the summer months, but due to their bulky construction do not work particularly well in the colder months.
Flat plate panels are best utilised in new builds where they can be incorporated into the build of the property and form part of the roof weathering system. Equally, for clients who prefer a more unobtrusive/integral look of flat plate panels, these can be incorporated into an existing roof and to the untrained eye look like large Velux rooflights.
Heelas installed a new bespoke 200 L hot water cylinder in the existing airing cupboard. The cylinder was a special/bespoke order due to the dimensions in their airing cupboard. Heelas only use high quality solar cylinders, which have high-efficiency finned coils to improve heat transfer from the solar fluid into the domestic hot water.
The panels were linked up to the hot water cylinder using pre-insulated flexible stainless steel pipework. Using this flexible stainless steel pipe work limits the amount of joints required and can often be run from the panels down to the airing cupboard in one continuous length.
The solar pumping station was installed at high level in the airing cupboard, with the solar controller unit fitted lower in the airing cupboard for ease of customer viewing/use. Once connected and all joints tested for tightness, the system is filled with a premix water/glycol mixture, giving protection down to -20° C.
Once the system is full of the glycol mix, the heat pipe evacuated tubes are installed into the manifold on the roof. Once fitted the system will immediately start to produce hot water (even on a cloudy day) Once running, a commissioning processes is carried out, where pump speeds and flow rates are set, expansion vessel charge pressure checked, control of temperature/parameters set and paperwork filled out/signed off.
Dr Burrows has reported back that his system is working extremely well and he is getting free hot water for up to 7 months of the year, which means his gas boiler does not run at all between April and October.
Dr Burrow’s testimonial
"The service fom Dan and his team was admirable in every way. The components they used for our solar heating and new boiler were very high quality, and any teething troubles were ironed out without any fuss or trouble. Dan checked in regularly to see everything was done to a very high standard and we're very pleased with the result. Now all we need is some sun!"
Dr Burrow, Oxford