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Lessons to be learnt in understanding biomass

With the temperature gauge plunging below freezing on a bleak December day, there are a lot worse places to visit than a boiler room.

The installation in question is the biomass boiler used by the Braywick Park sports ground in Maidenhead to supply heating and hot water to its changing rooms. With a variety of sports activities catered for on site, the facilities are in frequent use, especially at weekends.

Just over two years ago, the local council, which owns the Braywick complex, decided to install its new boiler. The contract was awarded to Vertdegree and involved the installation of a Euroheat biomass boiler.

Although there have been no problems due to the installation or reliability of the equipment, there were a number of issues that prevented any gains in efficiency being realised initially. This example gives an interesting insight into the use of new technology.

Teething problems

The project was delayed initially due to the need to reinforce the boiler room floor, says Vertdegree’s managing director Mick Atack. Once this initial problem was overcome, everything proceeded smoothly.

The company prefabricated as much of the system as possible at its Wiltshire base, simplifying installation and reducing work on site. The final connections were made and, when handed over to its new owner, the system was seen to be working to the manufacturer’s specifications.

Within a short time, however, Vertdegree was called back to the site to reset the controls. This was completed and the system was again seen to be working correctly. This situation proved temporary, however - the company was again called to complete the same task after another short period of time.

Both Mr Atack and the sports ground’s heating engineer agree that the problem did not arise from any technical issues with the installation; it was caused by people tampering with the controls and valves.

“We had to come back several times to retime the system,” says Mr Atack. “We found that the controls had been altered and people were opening the valves, thinking they needed to increase the output.”

The situation arose from the fact that a number of sports club members thought they needed to adjust the system when usage was at its highest on Saturdays and Sundays.

The major problem with this was that no one actually understood the system, as the council had not trained anyone to operate it. The result of this interference was that the system was frequently running at maximum output 24 hours a day and using excessive amounts of wood pellets.

Bad though the situation was, it could have been much worse, says Euroheat’s founder Simon Holden. Although the council had not opted to train anyone in the correct operation of the system, it had taken the wise decision to appoint a qualified installer that was situated sufficiently close to provide effective after-sales service.

“We advise all our customers to avoid installers who are not based locally,” says Mr Holden.

“If you use someone from the other end of the country, they are not going to be able to attend quickly in the event of a problem arising. Ideally you need someone who is less than two hours’ drive away and also able to give expert advice over the phone.

“We also advise customers to undertake training wherever possible, especially if the technology is new to them. We have our own training facility and 25 trainers around the country. There’s a lot to understand with biomass, it’s not the same as oil or gas.”

Finding solutions

Another potential problem was avoided with regard to the fuel. The decision to go for a wood pellet model was partly driven by the presence of a local supplier. The company, Forever Fuels, produces wood pellets from recycled wood waste and delivery involves a few minutes’ drive, boosting the environmental benefits of the technology.

The main problem here seems to have been that those tampering with the system did not understand the purpose of the heat accumulator. This holds 2,500 litres of water and must be heated to the correct temperature before being distributed around the system. The 100 kW output boiler is able to maintain the temperature easily once set up correctly and - most importantly - left alone to perform this function.

Although the sports ground heating engineer attends on a weekly basis, this is merely to empty the hoppers that contain the ash, estimated to be 0.5 per cent of the fuel input.

This practice is not considered to be essential, as the amount of ash removed is only minimal but the task is an easy one and guarantees that the hoppers are never full. Disposal is also easy, as the waste product can be used as fertiliser in the form of pot ash.

The system is now operating correctly to the satisfaction of all concerned and is expected to provide many years of effective service.