After two years of testing, boiler maker Byworth says it has proved that boilers which incorporate internally-finned X-ID fire tubes in place of plain boiler tubes greatly enhance the heat transfer rate by up to 85%.
This is achieved not only by an increase in surface area because of the tubes' internal spiral finning, but more importantly from the enhanced turbulence around the inner tube wall that the fins create.
Byworth has been testing X-ID tubes in a simulated and an actual steam boiler application and the tubes have been shown to increase the efficiency of the boiler by up to 2.5%.
It is estimated that most old boilers run at around 80% efficiency. This is for well-maintained boilers in good condition. Boilers in poor condition, especially if suffering from lack of or incorrect water treatment, will operate at much lower efficiencies, says Byworth. Boilers which are too big or too small for the steam demand will also operate at lower efficiencies.
A typical gas bill for a 10t boiler operating at 80% efficiency on a medium load would be around £30,000 per month, suggests Byworth. Replacing this boiler with a Byworth Yorkshireman2 incorporating X-ID fire tubes, running at 92.5% efficiency, would reduce the monthly fuel bill to around £25,000.
Contact: Byworth Tel: 01535 665225