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FIGURE 1 BOILER RESEARCH FACILITY

FIGURE 2 - AIR/FUEL RATIO CALIBRATION

the potential impact of a hydrogen
blend on current flue gas analysers and
combustion criteria used by Gas Safe
engineers is the focus of the research
presented within this article.
As part of the live demonstration at for each of the boilers twice a week. which determines appliance
Keele University, a bespoke boiler At the point of measurement, the fuel performance. This results in gas
research facility was constructed to gas quality was also recorded via the families and gas groups being defined
allow field research, using real world use of a gas chromatograph installed by Wobbe ranges. Alongside this, the
natural gas and hydrogen blends, to be on the network to measure fuel underlying research performed by
undertaken. The facility was built in compositions. The flue gas Dutton¹ et al in the 20th century
collaboration with boiler manufacturers measurements were repeated with derived appliance performance metrics
Worcester Bosch, Baxi, Ideal and two types of flue gas detector: as a function of the Wobbe number.
Vaillant. Each manufacturer supplied a 1. An instrument that directly measures Therefore, by constricting the range of
pair of identical boilers to be run carbon dioxide allowable Wobbe numbers, appliance
continuously throughout the 2. An instrument that indirectly performance could be managed. This is
demonstration. One boiler of each pair calculates carbon dioxide via an the rationale behind the current gas
was supplied with natural gas, and the oxygen measurement quality specifications of the Gas Safety
other with a hydrogen blend. This This allowed a determination to be (Management) Regulations², which
allowed real world operational data to made on the relative impact of a limit natural gas transportation to
be captured of identical boilers, where hydrogen blend on the two types of flue between 47.2 to 51.4MJ/m³. It follows
the only difference was the presence of gas analysers used by Gas Safe engineers. therefore, that appliance performance,
a hydrogen blend. The research facility The basis of gas family and gas group and by extension flue gas compositions,
is shown in Figure 1. demarcation is the Wobbe of a fuel, as it should by and large be a function of the
Flue gas analysis data was collected is the defining gas quality characteristic supplied fuel Wobbe and air/fuel ratio.

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ProgressiveEnergy.indd 2
ProgressiveEnergy.indd 2 13/08/2020 09:24