Gas 110 ECO

May 11, 2010 - 13:41

Carbon dioxide is often seen as the only polluting gas, but there are others that could be considered just as important and perhaps even more potentially harmful. Mark Northcott, national sales manager of Broag-Remeha, explains:

At the heart of the environmental debate there is, I believe, a growing – but deeply misguided – assumption that carbon dioxide (CO2) is the only environmentally damaging gas of major concern.

In fact, although it is, perhaps, the most important, CO2 is not the only gas worthy of consideration. One member of the nitrogen oxide (NOx) family of gases is many times more powerful than CO2 in terms of locking heat into the atmosphere. Nitrous oxide makes up a small amount of the atmosphere and is less than one-thousandth as abundant as carbon dioxide, but it is almost 300 times more effective at trapping heat.

But it is not just the global consequences that matter. NOx emissions also have significant local health effects. For example, NOx causes respiratory problems such as asthma, emphysema and bronchitis; aggravates pre-existing heart conditions; and even contributes to premature death. And the negative effects of NOx don’t stop there; it also has environmental impacts other than global warming. For example, it is:

  • A component in ground level ozone.
  • Contributes to acid rain.
  • Combines with particles to form smog, which visibility.
  • A greenhouse gas that contributes to global warming and climate change.
  • Leads to oxygen depletion in bodies of water and upsets chemical balance to aquatic wildlife.
  • Might contribute to biological mutations.

So NOx has both worldwide and local health implications, which begs a fundamental question: How can we reduce its impact? One answer lies in the type of boilers specified as the following figures show:

  • Broag-Remeha Gas 110 ECO modulating condensing boiler: NOx – less than 37mg/kWh at 91 per cent GCV
  • Traditional atmospheric boiler nearing the end of its service – NOx around 180 to 250mg/kWh at 50 per cent GCV
  • Pressure jet: NOx – around 160 to 220mg/kWh at 80 per cent GCV
  • New wood boiler: NOx – around 220mg/kWh at 80 per cent GCV (pellets)


I believe it is a mistake to focus only on carbon at the risk of forgetting the damaging effects of gases such as NOx. But this is not the only issue that should be influencing any discussion of climate change; financial considerations also play a crucial part in the debate. A design that remains on the drawing board because of excessive cost makes no contribution towards reducing global warming.
Consider the example of, say, the heating for 500 schools in the UK; using condensing boilers would reduce the environmental impact by:

  • NOx levels: 68.99 x 500 = 34,495 kg/year, a 90 per cent saving on site
  • CO2 levels: 12.04 x 500 = 6,020 ton/year, a 26 per cent saving on site
  • Gas savings: £1,686 x 500 = £843,000/year (4,194,500 cu m/year saved)
  • Electrical savings: £351 x 500 = 175,500/year (351,999kWh/year saved)


All these figures compare old pressure jet boilers to condensing boilers; the savings would be around 25 per cent higher if the comparison was made against old atmospheric boilers.

Bear in mind also that the NOx saving is just the saving in on-site combustion emissions. Besides, the mains electricity (351,999kWh) required to power pressure jet boilers is probably generated at just 30-33 per cent efficiency. This means we could be talking about a generating saving before grid losses of 1,000,000kWh a year. Think of the carbon and NOx reductions produced by not burning 1,000,000kWh of electricity a year.

It appears that we can save the planet at the same time as we save money.
I have no particular axe to grind – Broag-Remeha manufactures a wide range of solar, gas, CHP, wood, solid fuel, oil-fired, heat/water/air pump solutions.

I do, however, invite urgent debate on the vital questions surrounding the low carbon versus high NOx issue and the true contribution gas-fired condensing boilers and other technologies make in reducing greenhouse gases and whether they are economically viable. These are critical questions – the very existence of our planet’s ecosystem is at stake.

Article published in WNIB. July 2008

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