Ron Barker, group product manager at Ideal Boilers, explains why boilers still present the strongest solution for commercial and industrial applications.
It's all hands-on-deck for low carbon heating technologies as the government gives the go-ahead for the implementation of two new renewable heat incentives. There's no denying the UK is moving in the right direction in addressing its future energy supply and requirements, but there are significant hurdles.
Acceptance is the greatest obstacle for homeowners, who will require more generous and workable (fiscal) incentives. Uptake among business and property owners is also likely to remain low, as most renewable technologies available do not provide an economic total heating solution for commercial/industrial sectors.

So, it looks as if the commercial boiler is set to stay the product of choice for new and replacement applications for many years to come. Until its (unlikely) demise, the focus for manufacturers, installers, and end-users alike should be on replacing old, ineffective boilers, and installing high efficiency units that are properly maintained and make use of additional controls to achieve optimum performance. The initial outlay, and payback period, of a new high efficiency boiler is also more favourable to that of any renewable technology, even taking into account government incentives.

Save, save, save!

Replacing an old, heavyweight boiler with a modern standard efficiency boiler has the potential significantly to increase seasonal boiler efficiency from around 50 per cent to more than 80 per cent, when coupled with heating controls that comply with Building Regulations Part L2B. Seasonal boiler efficiency can be further enhanced to 90 per cent plus if a condensing boiler is selected, alongside system controls that ensure an optimum level of condensing operation.

In fact, system controls are key to optimising the overall performance of a large commercial or industrial heating system where part of the building is unused or does not require heating at all times. In this instance, adequate zoning is essential to ensure cost-efficient operation, allowing spaces to benefit from individual room temperature control tailored to their needs.

A smaller system can also benefit from greater control achieved at the simplest level by TRVs through to the likes of more sophisticated technology such as weather compensation. This ensures the boiler plant only raises system temperatures to the minimum required to meet the building loss, relative to the outside temperature that day. Optimisation is a further benefit, and ensures the system starts at the last moment so that no energy is wasted by achieving the set temperature before needed.

Part L2B of the Building Regulations sets out some minimum requirements for controls when replacing a boiler:

• zone controls required where the floor area is >150m2. as a minimum, on/ off control required

• demand controls eg room thermostat controlling a diverter valve, with constant flow temperature (standard efficiency boilers)

• time clock controls

L2B also awards credit points for meeting the required Effective Heat Generating Seasonal Efficiency to demonstrate compliance. The scale is relative to their benefits:

• 0.5 points = room thermostat, optimised stop only;

• 1 point = multiple boilers, sequencing of multiple boilers, monitoring and targeting, TRVs, full-zoned time control, and decentralised heating system;

• 1.5 points = weather compensation using mixing valve, and optimised start;

• 2 points = boiler over-sizing check, weather compensation (direct acting), and optimised start and stop;

• 4 points = full BMS.

Water-tight treatment

The efficiency of a boiler is further improved and maintained by water treatment best practice, a mandatory requirement of the Building Regulations. Hard water can cause scaling of a product, resulting in a loss of efficiency of heat transfer to system water. This means higher fuel consumption, and emissions. Just 1 mm of limescale on the surface of a heat exchanger can reduce heat transfer by as much as 10 per cent. So, when undertaking a replacement or refurbishment job, the system should be thoroughly cleansed and flushed before fitting new equipment. This helps prevent any dirt being dislodged or carried in the new system, which can be a cause of noise complaints.

Flexibility

The conventional boiler still offers the greatest flexibility for building managers in refurbishment and replacement projects with regards to meeting heating and hot water production.
If previously a single large boiler has been fitted, then consideration should be given to using multiple boilers, providing closer load matching, together with back-up for servicing and maintenance. In such instances, the most efficient option is to use a cascade system, with a mixing header employed to deliver both central heating and hot water loads. Using multiple boilers ensures closer matching of load requirements, resulting in greater efficiency and fewer emissions.