Energy Efficiency Case Study
VSD compressor, heat of compression dryer, and preheat boiler feed water for Weetabix
Compressor manufacturer Atlas Copco contracted IMEC to perform a turn-key installation and equipment start up for Weetabix.
Cains originally contacted IMEC to aid in the selection and installation of a new air compressor. During our facility assessment, we also identified that the facility was running out of hot water during high demand usage. We suggested a co-generation solution.
Project Description
In 2010, Weetabix invested in a comprehensive audit of their compressed air utility, partnering with National Grid under the O&M program. The audit identified several potential areas of savings including replacement of the existing compressed air equipment. Atlas Copco and IMEC engineered a solution that provided the following benefits to Weetabix:
a. Reduced the energy consumption of the compressed air equipment by combining two (2) compressed air systems in separate buildings into one. The entire facility is now supplied by an Atlas Copco model ZR250VSD-FF, 335 HP oil free, two stage air compressor with integrated VSD control.
b. Reduced the cost to dry the compressed air to the plant. Heatless desiccant dryers were removed from operation and replaced with an MD heat of compression desiccant air dryer that utilizes virtually no energy.
c. Improved the plant air quality. Oil lubricated compressors were removed from operation in the Packaging Building, reducing pressure drop and eliminating hazardous waste. The entire campus is now supplied with oil free, low dewpoint compressed air.
d. The ZR250VSD-FF package is outfitted with the Atlas Copco Energy Recovery option which delivers 190F water from the air compressor package. This hot water is used to preheat the Weetabix boiler make up water, significantly reducing the plant natural gas consumption.
e. A new closed evaporative cooling system was installed with a variable speed drive cooling fan. Since the majority of the heat load of the air compressors is used in the Energy Recovery process described in (d.) above, the heat load on the tower is reduced. Energy is saved through VSD fan operation as the previous tower fan was constant speed.
“Weetabix could not be more pleased with the results of this project.”
—Rich Guerriero, Weetabix
“We were able to upgrade our compressed air equipment and recapture the waste heat for our boilers. National Grid’s assistance with both the incentive monies and financing were essential in making the project move forward. We are saving money every month and enjoying oil free, low dewpoint compressed air in all of our manufacturing areas.”
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