Energy costs affect all grocery operations, but nowhere more than inside low-temperature distribution centers (DCs). Maintaining below-freezing temperatures throughout these voluminous facilities requires enormous amounts of energy. These operational costs gouge bottom-line profits. Energy Star research has found that $1 in energy savings is equivalent to $59 at the register, so reducing energy costs throughout the entire operation should be a strategic focus for all grocers.
There are several paths to lower energy costs in frozen food DCs: add efficiency technologies to reduce energy consumption, supplement expensive energy sources with alternative energy (wind, solar, etc.), or shift when energy is purchased to avoid high-priced peak period energy fees.
Add New Efficiency
When adding efficiency technologies to frozen-food distribution centers, operators often start with low-hanging fruit such as improving the insulation and envelope of the building, plus adding variable speed drives on refrigeration equipment along with LED lighting. All of these technologies provide incremental improvements, but even with these technologies the greatest energy hog by far is still the refrigeration system. To maintain acceptable temperatures and protect inventory, these systems must run almost 24/7.
Viking Cold’s Thermal Energy Storage (TES) technology goes beyond incremental efficiency improvements and can reduce energy consumption up to 35% or more in frozen-food DCs. TES systems are composed of sealed plastic cells filled with phase change material (PCM), intelligent controls and 24/7 could-based monitoring and reporting software. The PCM is installed high inside the distribution center and improves efficiency in many ways. First, the PCM absorbs up to 85% of the heat infiltration and consolidates the heat at the top of the facility. Second, the PCM transfers heat eight times faster than frozen food so the heat is more easily removed from the facility. Third, because the PCM absorbs most of the heat, operators can idle off their refrigeration equipment for long periods of time, typically during the day, which results in more runtime in the evenings. The cooler ambient temperatures at these times increase refrigeration efficiency. Lastly, rather than running below optimum refrigeration capacity all day, TES allows refrigeration to idle off or run “fully loaded” at its maximum efficiency more often. All of these factors result in removing the same amount of heat with fewer kilowatt hours.
Alternative Energy Plus Storage
Renewable energy sources such as solar or wind can reduce grid energy but have intermittency issues when the sun is not shining or the wind is not blowing. By storing that energy inside the freezer with TES, that energy can be put to use when it is needed most and makes the most economic sense, potentially even creating an opportunity to sell energy back to the grid. A frozen-food storage facility in San Diego installed solar and TES and was able to reduce overnight grid power by 95% and lower annual energy costs by 39%.
Safely Shift When Energy Is Purchased
Many utilities charge higher fees during specific times of the day, called peak periods, when there is more demand for electricity on the grid. To avoid more of these increased fee periods, some operators may subcool the food and the facility beforehand and then flywheel, cycle off refrigeration equipment, until temperatures meet their upper threshold. With TES systems, operators precool the PCM and are then able to safely extend the length of their flywheeling to avoid longer peak periods. One operator of a 93,000-square-foot distribution center who added TES is able to drop consumption 43% during a 13-hour peak period every weekday. The reduction during these periods has nearly cut the operator’s energy costs in half.
These methods of cutting energy costs are not new, but the most effective tool to maximize each strategy is new. Viking Cold’s Thermal Energy Storage adds efficiency and flexibility to help frozen-food distribution centers drive significantly more profits to the bottom line.
This post is sponsored by Viking Cold Solutions