One site, one system solution

Solar Thermal systems are now regarded as an accepted part of the microgeneration market. No longer is it a niche offering – it is now established and accepted. The market developments mean a clear growth in sales and installations but contractors must look to whole integrated systems and one-stop shopping to gain the greatest rewards from solar heating.

Solar Thermal has come a long way in a very short space of time – within the last five years it was still seen as being in the realm of the energy conservation enthusiast and not destined for the UK mass market. After a succession of gas and electricity price increases and a series of government and political motivations to make it happen, solar thermal has now began to be considered in a new light.

Everyone really is taking solar thermal very seriously as a viable addition to conventional heating fuels. A well designed system based solution should be able to contribute up to 60% of an annual domestic hot water bill.

Cost effective choice

It is not too extravagant a claim to say that solar thermal has entered the mainstream of domestic and commercial heating systems. The consumer, contractor, developer and local authorities are all convinced by the proposition of solar thermal solutions as a viable and cost effective choice, especially in today’s economic climate.

The Government has played a major part in this; the much mooted Code for Sustainable Homes sets out some ambitious targets for pushing the residential market down a much greener pathway. Contractors have been quick to grasp the potential of this new and fast developing market as a way of increasing their skills base and their own portfolio of services to differentiate them from competitors.

But there is one point of caution because the solar thermal market is still developing, almost on a daily basis, there are fewer acknowledged and widespread benchmarks of quality. Dedicated installation teams appear to be gaining the most of this new business area. But there needs to be close attention paid to the solar thermal product and component supply side of the industry.

There are a lot of smaller, fringe companies, from all over Europe and the world, supplying products into the UK as we embrace this new era of microgeneration solutions. The contractor and developer need to be cautious here. Integrated systems, the solar collectors, pump station, twin coil cylinders, and especially the controls, all need to be able to work together in harmony. Simple is clearly the best solution.

One supplier should be the single point of supply, information source and delivery. Another thing to remember is that just one point of contact will include any warranty issues or delivery problems.

Keep it simple

For a contractor there are stark and clear advantages of standardizing one simple supply route for all component parts. One supplier, after appraisal, should be able to offer one single delivery and just one point of contact. Who wants a logistical and administrative nightmare of solar collectors from one source and a cylinder from another?

All components that make up the system will be designed to work as an integrated system (e.g. intelligent controls that can hold off a boiler during periods of solar gain, despite the boiler being timed as being ‘on’ to maximise on efficiency and the solar yield). More importantly, the approval of the system as a whole will rely on all component parts of a given system being utilised.

There will be no issues with chasing round trying to find parts to adapt a seemingly cheaper cylinder, to accommodate the solar components that they are clearly not designed to accept.

All safety devices should also be included when sourcing from a single, approved supplier, such as an adequately-sized expansion vessel and protection vessel for the solar circuit. Requirements for unvented storage water heating systems and their installation are laid down in Part G3 of the UK Building Regulations. 

These regulations state that unvented hot water storage systems with a storage capacity greater than 15 litres must be safely installed by a competent person who holds a current Registered Operative Identity Card. The card can be obtained by attending a CITB (Construction Industry Training Board), BPEC (British Plumbing Employers Council), European Registration Scheme or BPEC Certification approved training course.  Unvented training is available through colleges and manufacturers who may be able to combine this with product specific training.

System design

Guidance on system design and sizing can be sought from the Domestic Heating Compliance guide. Using this guide, in conjunction with Part L energy efficiency training, installers and specifiers can be sure that the solar coil is adequately sized, that the solar cylinder allows adequate volume to maximise solar gain, and that the cylinder is properly insulated.

With a fully approved solar system and cylinder, much of this work is taken care of by the manufacturer. Provided that the installer makes necessary provision to counter solar shaded areas, takes account of roof orientation where a perfectly south – facing roof is not available (and let’s face it, when is it?) and sizes the system for the needs of the application, the integrated system approach offers as near a plug and play solution as you’re likely to find.

The way forward

Most of the established manufacturers have complete and integrated systems, and they are usually backed up by a nationwide service organisation or network should any issues arise. There are huge solar gains to be made, but integrated systems, all from one manufacturer, are obviously the way ahead.

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