INDUSTRIAL & COMMERCIAL HEATING REFURBISHMENT Flow
Heat source
Load Return
Figure 2: A simple single pipe system that would be a feature in many of the 5,000 listed UK schools. (Source: CIBSE AM14)
Load Load
that may be gleaned from a one-off visit – such as schematics, equipment schedules, original commissioning data and connections with other systems – AM14 then expands into the basics of longer-term evaluation and continuous monitoring, and how the data might be analysed. The feasibility for refurbishment (rather
than replacement) will, of course, depend on the condition of the existing heating plant. AM14 outlines the principal components that would be included in a condition survey and indicators that signal the need for further investigation such as corrosion, signs of poor boiler combustion, leaks and excessive noise. The practicality of any refurbishment
heating option must depend on the load requirements of the building both in terms of simple heating loads and the capability of the renewed systems to meet the specific demands of the heating distribution systems. The manual provides a brief summary of the necessary calculations and identifies the relevant resources that can be used to establish loads and distribution temperatures to meet the requirements of the building. Recognising the increased emphasis on
Figure 3: Example of solar thermal integrated into a condensing boiler heating system. (Source: CIBSE AM14)
Generic heating systems are outlined
AM14 AND RELATED CIBSE GUIDES
Most CIBSE members are familiar with the CIBSE Guides (particularly Guide A ‘Environmental Design’, Guide B ‘HVAC & R’ and Guide C ‘Reference Data’) that in themselves provide an invaluable source of information for designers and operators of building services. But, aside from all the other equally important guides, there are many more CIBSE publications that meet specific needs and, with the advent of the CIBSE Knowledge Portal (
www.cibseknowledgeportal.co.uk), they are free and instantly available to CIBSE members. A prime example of this oft neglected wealth of information and knowledge is the wide range of application manuals that have been produced by CIBSE by drawing on the expertise of teams of industry specialists. This range has recently been augmented with the new AM14 – Non-domestic hot water heating systems guide.
to assist in identifying the underlying systems in buildings. These range from the one-pipe systems (see Figure 2) that were so popular in schools in the first half of the last century and remain in many thousands of listed buildings; through to widespread two-pipe systems and manifold systems used in more modern zoned chilled ceiling and fan-coil applications.
The manual’s coverage of refurbishment articulates the techniques for evaluating the whole life costs and payback for systems
Being able to identify the system
on site is more challenging than the simplified schematics may suggest; but AM14 does provide some guidance on the methodology required to successfully evaluate existing installations. Starting with a list of the performance information
40 CIBSE Journal February 2012
reducing the environmental impact of the heating plant, there is an important section outlining the main low carbon technologies that are likely to be considered. This includes not only the technologies themselves (such as solar thermal, CHP and biomass) but also how, in general terms, they may be integrated into existing systems (as shown in Figure 3). The manual’s coverage of refurbishment
articulates the techniques for evaluating the whole life costs and payback for systems and identifies appropriate performance criteria for replacement boiler plant. This 125 page document provides an
accessible reference that describes a logical sequence of processes and underpinning knowledge for engineers to design efficient heating systems. There may be opportunities in future editions to develop some case studies that cover experience of refurbishment as well as potentially including sections on domestic hot water generation but even in this first edition the collected wealth of guidance and information is a worthy addition to the CIBSE technical resource. CJ
l Prof Tim Dwyer is CIBSE Journal technical editor and a teaching fellow at University College London
www.cibsejournal.com
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