Flowers Foods: 40-year Old Bakery Conversion Prioritizes Energy and Water Performance
Solution Overview
To meet the increasing demand for Dave’s Killer Bread (DKB) organic products in the Mid-Atlantic market, Flowers Foods converted an existing bakery into a state-of-the-art, energy-efficient, sustainable bakery.
Background
Flowers Foods operates 46 bakeries that produce a wide range of products for retail and foodservice customers. Its Lynchburg, Virginia, bakery has been in operation for more than 40 years. To meet the increasing demand for Dave’s Killer Bread (DKB) organic products in the Mid-Atlantic market, Flowers Foods converted an existing bakery into a state-of-the-art, energy-efficient, sustainable bakery. The Flowers engineering team incorporated many energy and water efficiency technologies into the design of the Lynchburg bakery, which is being used to test and demonstrate sustainability features. Based on five months of operational data, the production line upgrades are delivering an energy savings of 22.6% and water savings of 64.1%, and the company plans to implement many of the same technologies and practices at its other 46 manufacturing facilities and over 900 warehouses.
When Flowers Foods invests in new bakeries, production lines, or upgrades to existing equipment, sustainability features are an integral part of the design process. The company evaluates energy usage at the start of capital projects to ensure that new production lines not only improve productivity and quality but also deliver significant energy savings. As part of the Lynchburg project, Flowers Foods also took advantage of a performance-based grant through the State of Virginia and received $250,000 to cover the cost of the high-efficiency energy and water technologies installed in the plant.
Solutions
The Flowers engineering team incorporated many sustainability features into the bakery’s new design, including heat recovery, electric blowers in place of compressed air, a new variable frequency drive (VFD) air compressor for the trimming machine, LED lighting, recycling process improvements, and refrigeration upgrades. 808 lights were replaced with LEDs, and a high efficiency 150 hp VFD-equipped air compressor was installed to replace a less efficient 300 hp fixed speed model. The older chillers were replaced with new high-efficiency chillers and a waste heat recovery system was also implemented to increase energy efficiency and reduce process heating costs.
The heat recovery system is integrated internally into the plant’s catalytic oxidizer emission control system. Waste heat from the oxidizer is recovered to heat hot water for tanks, pipe and tank jackets, and ingredient water. The oxidizer recovery system can generate 0.75 MMBtu/hr. of energy at the source and includes an integrated coil and fin heat exchanger used to recover waste heat from the catalytic oxidizer exhaust. The installation includes custom programmable logic controllers (PLCs) and bypass dampers that regulate the exhaust flow rate through the coil heat exchanger, as well as the amount of heat applied to the coil. Components relating to this system will be preassembled and pre-tested before shipment to the site. With the addition of the heat recovery system, two natural gas-fired boilers were able to be removed.
Figure 1: Piping components of the heat recovery system.
Other energy and water efficiency measures were integrated into the new cooling and refrigeration systems. These included refrigeration system controls that took advantage of variable flow control sequences using VFDs to reduce pumping system energy use. The new air-cooled chiller system uses significantly less water for cooling as well. In addition, new production processes were implemented to reduce water use. For example, the previous production line used a series of tanks that required regular cleaning. The new production line does not need these additional tanks and they were removed. Lastly, the recycling program was improved by installing a baler on location to improve storage and increase revenue from cardboard recycling. These energy-saving projects decreased the energy intensity by 22.6% from 5.2 MMBtu/ton to 4.0 MMBtu/ton in the first five months of operation. Water use decreased by 64.1% from 389.9 Gal/ton to 140 Gal/ton over this same period.
Other Benefits
The replacement of old lighting with new LEDs not only saved energy, but also improved lighting levels and reduced heat in the bakery. This improved working conditions in the bakery and reduced HVAC energy use. Due to the success of the energy saving measures implemented at Lynchburg, Flowers Foods’ engineering team will continue to incorporate similar technologies when planning facility upgrades and new production lines across its network. With 46 manufacturing facilities and over 900 warehouses, these best practices will make a significant impact on reducing energy consumption and greenhouse gases (GHGs).