High-tech, more energy-efficient boilers can be seen as a confusing or expensive choice. But this can be a short-sighted and costly viewpoint, as Viessmann's Stewart Purchase tells HVR
AS GAS and oil prices rise, are we in the industry meeting the needs of our customers by ensuring that we sell the most energy-efficient boilers we can? Probably, sometimes.
But we may be letting the customer down by not hitting the energy use when boiler replacements are discussed.
A case in point is condensing boilers. In a commercial building, energy bills can be tens of thousands of pounds a year. Hence, fitting condensing boilers with proper controls may well be paid for in months compared with a low-cost conventional solution.
Put another way, the lifetime fuel and other costs of the system for the client may well be dozens or even hundreds of times greater than the capital and installation costs.
Condensing boiler technology should not frighten customers either in price or complexity, says Stewart Purchase of Viessmann. For example, the company's new Vitocrossal 200 range of condensing gas boilers is based on the established Viessmann designs, including stainless-steel heat exchangers, he says. The new range offers 'outstanding performance at affordable prices,' he adds.
Including in the new boiler's specification is the Viessmann pre-mix MatriX burner. This is dedicated to the boiler and gives a wide modulation, down to 30% of output, lowest in class NOx emissions and noise levels as low as that of domestic boilers.
Leicester Cathedral has a boiler house with 14th century foundations but a modern heating system. Four Viessmann Vitodens 300 gas boilers at 66kW each are installed in a cascade system.
The boilers have a weather-sensitive control connected to the boiler's own Vitotronic control. The four-boiler layout was chosen to save space in a restricted boiler house but also because access is limited to a narrow winding staircase, also 14th century. The cathedral has monitored gas consumption during the 12 months since installation, and this shows a reduction of 24·9%. The installation was by Air Right of Leicester.
Looked at simply, are we in H&V using high technology because it is there? Since we are now able to monitor and control buildings on our laptops from anywhere in the world, we want to build this in wherever we can. BMS suppliers tend to come late in the supply chain, and often have no direct link to the client. Hence, the technology can end up making life more difficult for them rather than the other way round.
Four key factors stand out. In most medium-sized projects, heating and hot water is likely to be the single largest energy use, and usually the majority one.
The client is concerned that the fuel bill is being kept to the minimum, that the boiler plant is not running into trouble, and that the building is being kept warm and watered. And all this delivered simply and without too much input from them.
As condensing boilers increase in use, we need to ensure they deliver the extra savings the client has been promised.
This suggests that, in those thousands of buildings where the boiler plant is the key energy equipment, control should concentrate on the simplest energy solution for the boiler. According to Viessmann, as it is both a boiler and control manufacturer, it has tried to make the solution one of complete integration.
New College Swindon is an example of a project where the design and build contractor, NG Bailey of Bristol, used the boiler and dedicated controls approach.
Heating for the new college comes from a Vitocrossal condensing boiler working alongside two Vitoplex boilers using modulating Nu Way burners. The LPHW system serves a mix of radiators and 11 air handling units with weather compensation directly feeding into the Viessmann control. The objective of the designer was to incorporate all boiler-related controls and operating data into one centre - in this case a Vitotronic 333, which then linked to the BMS via a BUS.
NG Bailey worked with Viessmann to ensure the combined package met the operating brief. This means that there is a single and clear line of responsibility for the boiler's operation and energy efficiency.
Additionally, the Vitotronic standard package offered considerable capital cost savings compared with a bespoke control, Viessmann says. Consultant was Hoare-Lee of Bristol.
Lastly, the dedicated control route can monitor the boiler operation for safety and reliability and in the event of a problem alert the service provider and give a precise message or read out, pointing to the component or other failure.
Viessmann 01952 675000
www.viessmann.co.uk