Jeff House considers the role of prefabricated boiler systems in the low- and zero-carbon technological environment to meet space-heating requirements.
Prefabricated heating solutions offer a multitude of benefits for new build and retrofit projects, the main attraction being that equipment arrives on site fully assembled and tested. This approach can significantly reduce project cost and time on site in comparison to the traditional approach of separate delivery of component parts for on-site assembly.
In the case of retrofit or replacement applications, a prefabricated solution will help minimise losses through security issues and also reduce building system downtime during installation and commissioning. In addition to these practical advantages, there is a further significant benefit that might be overlooked. The assembly of component parts into a complete entity, the delivery of the unified package on a single visit and the tailoring of the prefabricated solution for local ‘plug-and-play’ connection all contribute to an appreciable reduction in the carbon footprint of the application. This aspect will undoubtedly play an important part when life-cycle performance is assessed, in compliance with energy-efficiency and labelling directives, regulations and measures.
The Government’s commitment to achieve an increase in energy efficiency and a reduction in harmful emissions is total and unswerving, borne out by a series of strategies designed to not only encourage householders and businesses to switch from using energy based on fossil-fuels but also to aim to become energy self-sufficient by utilising small-scale renewable, low-carbon generation technology. In the latter case, the microgeneration industry is being encouraged, and has agreed, to accept the responsibility of moving into the energy mainstream. Consequently, it should be no surprise if the major, if not the first, concern of the building contractor will be to seek to incorporate low-carbon, renewable-energy generation into building design — whether the project concerns a new or existing structure. The Government’s microgeneration strategy goes further, emphasising the importance of the industry taking a whole-system approach to microgeneration. In this context, a prefabricated solution that incorporates a small-scale generation capacity would be a valuable option.
In the case of one microgeneration technology, combined heat and power (CHP), the UK is seen as one of the world leaders. Indeed, micro-CHP is a reliable and mature technology that produces not only heat to help meet the water- and space-heating demands of the building but also generates electricity that can be offset against electricity charges, with any excess exported to the National Grid. As part of a prefabricated solution, this dual capability will make CHP suitable in many situations where a reduction in the use of fossil fuel sources is to be achieved.
Because the generator should be used as frequently as possible to maximise performance, CHP is particularly suitable in a multiple-occupancy building. The capacity to meet almost continuous electricity needs as well as a large heat load means that CHP can achieve a notable reduction in the level of harmful emissions and provide real value for money. A prefabricated system with CHP as an integral part could reduce a building’s existing carbon footprint significantly. The purchase cost of the CHP is subject to a lower VAT rate of 5%, and industry-leading solutions enable Enhanced Capital Allowances to be claimed. The electricity produced and the fuel consumed are exempt from the Climate Change Levy.
The installation and commissioning of the selected prefabricated solution does not end the story, as the ongoing effectiveness of the package will need to be assured. Although quality and performance will have been reviewed and tested during the prefabrication process, regular servicing arrangements should be put in place, even if this is not a recommendation of the building’s energy-performance certification. It might be considered sensible to use the services of the company that assembled the prefabricated package, particularly as it would be able to source the correct component in the event of any replacement being necessary, without involving a performance certificate or labelling reassessment. The continued operational efficiency of the installation will also be a major factor if any tariff entitlements are established under a Government incentive scheme or plan.
The completeness and tailored specification of the preferred prefabricated system can have significant financial and environmental benefits. The integration of a micro-generation capacity will greatly reduce grid electricity costs and can lead to the possibility of deriving income from any extra capacity generated. Further financial benefits may accrue as Government incentives planned for implementation during the next year or two are finalised and rolled out. Importantly, the whole-system characteristics of the combination will mean the total energy-efficiency assessment, required for the intended Eco-design Directive ‘Installer label’, will be simplified, only involving the company that assembled the system. A more general benefit will be that the reduced carbon footprint of the host building will contribute to the attainment of overall UK carbon-reduction targets.
Jeff House is applications manager with Baxi Commercial Division.