Baking & Snack - May 2018 - 106
Heat recovery combined
with absorption refrigeration
chill water and glycoljacketed mixers.
Pepperidge Farm's bakeries have invested in efficient
LED lighting and motion sensor technology, which can
nearly halve the electricity demand for lighting in some
facilities. By converting to low-charge ammonia and
CO2, four bakeries have phased out R22 refrigerants,
which deplete the ozone layer. "The use of these natural refrigerants significantly improves energy efficiency,
lowers energy costs and reduces greenhouse gas emissions," Ms. Maltenfort said.
Campbell is also investing in renewable energy projects at the Pepperidge Farm bakery in Bloomfield, CT,
with a 1 MW solar array, and 1.2 MW and 1.4 MW fuel
cells - the latter of which is equivalent to enough power
for about 1,400 homes.
Likewise, Clif Bar works to fine-tune its process and
operations to increase efficiency and improve yield at its
Indianapolis and Twin Falls plants. "We have a manufacturing execution system that allows us to track the bakery energy, waste and water usage down to a very granular level and include these KPIs in monthly reviews," Mr.
Monahan said. "This has allowed us to take a closer look
at both bakeries to understand trends and fluctuations."
Specifically, Clif Bar reviewed the energy consumption of its ovens in Twin Falls to tune them. Today, the
bakery produces three times as many bars with less energy than at the project's beginning. Additionally, variable-frequency drives (VFDs) on mixers, the refrigeration system and compressed air units capture low-grade
heat that contains enough energy to provide hot water
and space heating. Latent heat harvesting on oven exhaust stacks recirculates excess heat for baking and adds
to the efficient use of energy at the bakery. Efficient refrigeration equipment and processes trim about 40% off
typical bakery refrigerant emissions. In addition, 100%
of the electricity required to power the bakery is covered
by renewable energy credits from an Idaho wind farm.
Air Management Technologies
106 Baking & Snack May 2018 / www.bakingandsnack.com
It doesn't stop there. When equipment suppliers submit a proposal, Clif Bar strongly encourages them to
study its Planet Aspiration initiatives. "We ask them to
bring their creative planet solutions to the table, which
usually means solutions that have sustainability benefits," Ms. Hammond explained.
Clif Bar works with NativeEnergy and the HelpBuild
Carbon Offset program to run a carbon-neutral business. "Clif Bar has helped support the development of
36 renewable energy and greenhouse gas reduction
projects, including five school-owned wind turbines in
Indiana, inspiring a new, statewide clean-energy curriculum available to grades K-12," Ms. Hammond said.
Free at last
In industrial bakeries, ovens - the largest energy-consuming system - represent up to 35 to 40% of total
carbon emissions, said Somesh Veerappa, chief ovens
engineer, Spooner Vicars, part of the Middleby Bakery
Group. Among all baked goods, he added, bread contributes the most to carbon footprint emissions.
Heat recovery systems not only slash bakery emissions but also harness waste heat ejected into the atmosphere from catalytic oxidizers and other sources.
Scott Houtz, president, Air Management Technologies
(AMT), noted the systems repurpose the heat to support thermal processes such as proofers, basket washers,
water heating and makeup air. Capabilities also exist to
generate low-temperature refrigeration for use in glycoljacketed mixers, produce chilled water, and refrigerate
coolers such as retarders or ingredient rooms.
Mr. Houtz called waste heat a "free" utility paid by gas
and electricity already consumed. A properly engineered
and constructed heat recovery system provides substantial annual savings, often up to or exceeding $100,000
per year depending on throughput and regional energy