On the boil

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We look at some of the latest technological trends and developments on the international boiler and water heater front

Boiler manufacturers are looking at reducing harmful emissions, as well as reducing energy costs for end users by increasing efficiencies, or even looking at new fuel types.

Fulton of the US was recently awarded a grant from the New York State Energy Research and Development Authority to develop an ultra-high efficiency condensing natural gas/B-100 biodiesel-fired version of its Vantage boiler.

“We see biofuels as a premiere energy source people for the future if, in fact, petroleum type fuels are no longer available or become expensive or difficult to obtain,” says Fulton Heating Solutions Inc. commercial heating product manager Erin Sperry.

SULPHUR-FREE FUEL

The biodiesel-fired version of the Vantage boiler will take advantage of the unique features of sulphur-free fuel, while achieving ultra-high efficiencies. Such an innovation stands to fill an important technological niche in the boiler market. While gas-fired condensing boilers can provide efficiencies over 89 AFUE, most conventional oil-fired boilers are limited to operating at lower efficiencies due to the corrosive nature of the sulphur content of the fuels. Unlike most fuel oils, biodiesel, which is derived from vegetable oil, is non-toxic, biodegradable, sulphur-free and, when burned, releases less harmful pollutants into the atmosphere.

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“There are no commercial-size boilers on the market that can condense on No. 2 oil because of the sulphuric acid production associated with the combustion process,” says Sperry. “If it is not possible to produce flue gas condensate, it is not possible to get the highest efficiencies from operating the boilers.

The ability to condense on an oil that would not result in sulphuric acid production leads to being able to have ultra-high-efficiency condensing boilers with more than just gas-fired options.” The ultra-high efficiency boiler will be beta-tested towards the end of 2009. If all goes according to plan, the three million Btu version should be available in 2010.

Lochinvar’s Sync boiler features smart-touch control with a touch-screen user interface. This allows contractors to integrate boilers into heating systems with less effort and with more control, says marketing director Stirling Boston.

The modulating condensing design is housed in a compact footprint that features multiple venting options for greater installation flexibility and ease of maintenance.

These improved control strategies are not only user-friendly, but they also help combat real-world scenarios such as part load heating days, energy saving pumping and piping strategies, system oversizing and limitations in technology for maintaining the heating system at low loads.

“Due to these variables we are sometimes not able to operate a complete heating system at efficiencies as high as is desired. However, we will continue to introduce new technologies and controls designed to provide higher realised system efficiencies,” explains Boston.

Bryan Steam recently introduced its Triple-Flex ultra high efficiency condensing boiler, which uses a variable speed motor/blower for precise control and energy savings. This US manufacturer is also researching and developing the latest in control technologies to deploy in the market. “We have seen a steady increase in the use of PID control technology for more accurate control of the boiler for precise output to the heating/process load.

“The use of various protocols for communications with the BMS is a continual challenge as the industry works to find a common standard,” comments national sales and marketing manager Ronald Guth.

“We are also using the Honeywell Sola hydronic control to manage the boiler while interfacing with the BMS to change the water supply temperature as needed in order to reduce the loads on the system pumps and chillers, for example.”

Since the Triple-Flex boiler is not temperature dependent, it also provides ultra high efficiencies. Most condensing boilers can achieve efficiencies in the 95% to 98% range when operated with cool return water of 80°F at low firing rates. However, these are not real-world operating conditions. When these same boilers are fired at maximum rate with nominal 160° return water and 180° supply, efficiencies are closer to 86% to 87%.