Engineering Tomorrow allows environmentally-focused retailer to achieve its goals

Tuesday, August 6, 2019

Founded in 1912, Weis Markets began as a neighborhood grocer in Sunbury, Pennsylvania—a small town nestled against the Susquehanna River. Today, the company owns more than 200 stores throughout the Mid-Atlantic, from New York to Virginia, and employs more than 19,000 people in its stores, distribution centers, corporate office, and manufacturing facilities. Still run by the Weis family, Weis Markets has today, and throughout its history, rooted itself in steadfast dedication to local farmers, giving back to its communities, and minimizing its environmental footprint.

In fact, the supermarket chain has set ambitious goals of reducing its carbon footprint by 20 percent by 2020—an objective that it has already surpassed; since 2008, Weis has reduced its carbon footprint by more than 20 percent. It also aims to reduce its recycling rate by five percent each year, with an end goal of zero waste. A member of the US Environmental Protection Agency’s GreenChill program with 15 GreenChill-certified stores, Weis is striving to reduce its energy use by two percent annually and has saved more than $2 million by deploying efficient and environmentally-friendly equipment throughout its stores to reduce costly and harmful refrigerant leaks.


Evolving system design to meet goals

What Weis Markets has accomplished in terms of sustainability and efficiency can in part be attributed to a forward-thinking and open-minded team—and a willingness to evolve its refrigeration design strategy.

Ten years ago, Weis employed a refrigeration design that featured two low-temperature and two medium-temperature central distribution racks per store, eventually transitioning from R-502, a chlorofluorocarbon (CFC), to R-404A, a hydrofluorocarbon (HFC) blend with lower ozone depletion potential.

However, increasing scrutiny of the environmental impact of refrigerants, evolving regulations, and an opportunity to further reduce costs led Weis to transition to a design utilizing one low-temperature rack, one medium-temperature rack, and a secondary glycol medium-temperature rack. This design ultimately moved Weis from R-404A (GWP 3943) to lower global warming potential (GWP) and more energy-efficient options R-407A (GWP 1923) and R-448A (GWP 1273). By incorporating microchannel condensers, variable frequency drives, Danfoss AK-CC 550 and AK-CC 210 case controls, and Danfoss AB-QM™ pressure independent control valves on the glycol loop, Weis reduced its refrigerant charge by 65 percent and lowered operating condenser design temperatures—and, thus, compressor design conditions as well, cutting energy costs even further.


Introducing natural CO2 refrigeration

But in 2018, Weis worked with Danfoss to take the next step toward dramatically slashing the global warming potential of its refrigeration systems; its first transcritical CO2 refrigeration system went live in July 2018.

Supermarket systems can leak up to 20 percent of their refrigerant, but by replacing HFCs with CO2 reduces refrigeration cost, accelerates positive environmental impact, and serves as a futureproof solution in a period of evolving regulations and standards.

Non-toxic and non-flammable CO2, which offers zero ozone depletion potential and GWP as low as one, can deliver very high performance in some commercial refrigeration systems through improved heat transfer and low condensing pressures. It also has high volumetric efficiency, low power consumption, and refrigerant charge reduction.

“We initially discussed partnering with Weis to do a CO2 store a few years ago,” explained Stephen Renz, account manager at Danfoss. “They’ve been a tremendous proponent of environmentally-friendly refrigeration design in their stores, so once their team was comfortable with design for the new transcritical CO2 store in Randolph, New Jersey, we were thrilled to help them bring it to life.”

In fact, the Randolph store was designed with multiple sustainability measures in mind. In addition to environmentally-friendly CO2 refrigeration, the 54,000-square-foot store features LED lighting; low-flow devices that support water conservation efforts; and energy control through demand response programs to reduce power usage during peak days and to reduce the store’s load on the power grid. The store also uses enclosed refrigeration cases to reduce energy use, and advanced refrigeration technologies—like those supplied by Danfoss, to reduce refrigerant use by 60 percent compared to conventional systems.

Read the full case study here