STS Case Studies

Wegmans is a family-owned U.S. regional supermarket chain, ranked in the Top 75 North American Food Retailers based on sales volume.

Their bakery facility in Rochester, NY, currently handles the production of all baked goods for the chain of over 80 stores. It is a multi-temperature facility incorporating low temperature spiral freezers and holding freezers, mid-temperature chill rooms and dough processing lines, and higher temperature produce storage and air conditioning for factory and offices. Owing to the site’s expansion over a number of years, the refrigeration loads are served by 45 localised small to medium refrigeration systems, the majority utilising R22 as the refrigerant. With the phase out date of 2020 approaching for R22 and other HCFCs, the site wanted to explore system options that would provide the best combination of energy efficiency, reliability, longevity, safety and ease of maintenance.

STS carried out an initial audit of all refrigeration and heating loads at the site, and obtained data for the seasonal operation of some of the larger systems. Using this data, the total refrigeration loads and energy usage for the different temperature levels were modelled. Several practical options for central and distributed refrigeration plants were assessed on the basis of energy efficiency, safety and capital cost, considering both natural and synthetic refrigerants. Ultimately, a central plant utilising ammonia as the high-temperature primary refrigerant and carbon dioxide as both the low-temperature primary and medium-temperature secondary refrigerant provided the best overall characteristics. Preliminary design of the plant showed that the ammonia charge could be reduced to around 2,000lbs for a total system cooling capacity of just over 4MW, with indicated energy savings greater than 30% against the existing cooling systems.

In the next phase of the project, STS produced a performance specification for the new plant, including detailed requirements for specific system attributes and equipment. STS will continue to work with Wegmans to assist in the final delivery of the project before 2020.