Process heat pilots uncover serious savings

MANY businesses could be making significant savings with simple adjustments to their process heat systems, according to two EECA pilot studies.
While boilers tend to toil away unseen, they are at the heart of most industrial and commercial businesses’ process heat systems, providing heat and energy for a wide range of manufacturing processes.  
Process heat is a significant area of energy use: New Zealand’s industrial and commercial businesses use more than 100 PJ each year to generate it – nearly twice what is used annually by the entire residential consumer sector. 
Recent pilot studies indicate, however, that many boilers and wider process heat systems are wasting thousands of dollars in running costs, which generally could be easily avoided.
“From the work that we’d done with businesses over the years we estimated that most process heat users could probably improve the efficiency of their systems by five to 20 percent,” says EECA Business programme manager Murray Bell.
“To look more closely at some specific opportunities, we decided to run two pilot projects.”

Boiler combustion tuning
EECA’s pilot study on boiler fuel combustion tuning looked at nine boilers of different sizes in a diverse range of businesses, including an art gallery, a laundry business, a vegetable processing factory and a large wood processor. In seven of the nine cases, the boiler was found to be operating outside optimal fuel combustion efficiency levels.
For the four smaller boilers looked at, a $690 tuning resulted in fuel savings in every case, ranging from $1400 to $17,500. For the five larger boilers, one was found to be operating optimally already, but tuning of the other four – at a cost of between $1000 and $3000 – resulted in savings ranging from $3000 to $120,000.
“While you don’t get the same percentage improvement in bigger businesses, because they generally  have good maintenance systems in place, there are still some pretty significant dollar savings to be made,” says Kelly Williams, operations engineer at RCR Energy Service, who performed three of the boiler tune-ups in the pilot.
“For smaller businesses, the potential savings are generally a much larger proportion of their operating costs, so it’s something they should really be looking at.”
The pilot found that operating at maximum combustion efficiency saves fuel by reducing the amount of excess air that is heated by the fuel and passes directly out of the chimney. It also reduces build-up of soot deposits on heat transfer surfaces, which allows better transfer of heat.
“Obviously if your boiler’s old and inefficient, tuning won’t give you the kind of savings you’d get by simply replacing it. But for many businesses, there are some good efficiency and savings opportunities to be gained from boiler fuel combustion tuning,” says Williams.

Thermal audits of process heat systems
Williams is also quick to point out that the boiler is just one part of the wider process heat system. “To get industrial plant operating at maximum efficiency, it’s really important to take a holistic view of the system. The heat plant and the production process are actually two halves of one system.”
In another pilot study, EECA helped fund thermal audits of the process heat systems in four large businesses: Canterbury Woolscourers, Dongwha Patinna Mataura, Mainland Products Christchurch and Tatua Dairy Products. The audits identified significant savings opportunities for all – many of which have a payback period of less than a year.
The Canterbury Woolscourers audit, which cost $14,900, identified $174,000 in energy savings opportunities with a payback period of less than 12 months. It also found a further $76,000 of potential savings with a payback period of between one and three years.
“It’s been really worthwhile getting an outsider’s perspective on things and I’d certainly recommend it to other businesses,” Canterbury Woolscourers general manager Tony Cunningham said of the thermal audit.
“We’ve got good, skilled staff in-house working on our systems every day, but getting a different viewpoint and testing the boundaries has turned up some savings in our process heat system that we might otherwise not have found. We’ve now got an action plan and timelines in place to get these energy-saving measures in place.”
During June 2010, EECA Business will be hosting a series of workshops on process heat efficiencies. For more information or to register your interest, email

Enquiries: Miranda James
Senior Communications Adviser
Energy Efficiency and Conservation Authority (EECA)
P O Box 388 • Wellington
T: 04 470 2413 • F: 04 499 5330 • M: 021 444 178





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