When Renteknik Group — experts in energy optimization and management — was tapped to help a southwestern Ontario grocery store take advantage of the Independent Electricity System Operator’s (IESO) saveONenergy incentive program, they engaged Emerson Climate Technologies for real-world ways to improve efficiencies in the store’s legacy refrigeration system. The store utilized low- and medium-temperature parallel rack systems running on 10 Copeland™ semi-hermetic compressors.
Recent regulatory actions by the EPA and the DOE have created a great deal of turmoil within the HVACR industry. In many ways, it’s a perfect regulatory storm that will have huge impacts on the future of our industry.
Because of these impacts, we need to evaluate all ideas, strategies and emerging technologies to determine how to best proceed. That’s why we created our E360 Forum — to facilitate a dialogue that will answer these questions and help shape the future of HVACR.
In conjunction with a major travel center, we presented an educational session at the 2015 NACS Show, focused on energy management best practices for convenience stores. If you missed it, don’t worry. We’ve compiled the highlights below:
From traditional to advanced energy management
We’ve all visited a convenience store in the middle of the afternoon with its external canopy lights on, or walked into a store that is uncomfortably warm or too cold. Lighting and temperature control through scheduling is a basic energy management system function. More advanced systems today incorporate refrigeration equipment and remote monitoring, and the latest, complete systems offer control and monitoring of foodservice, fuel and other critical equipment.
With an advanced system, a typical convenience store might see $4,000 in annual energy savings and $6,000 in annual operational savings, resulting in a possible payback period of less than 24 months — and it can be faster, depending on store size and functions.
With increasing regulations prompting a shift toward sustainable alternative refrigerants, retailers are looking more closely at CO2 transcritical booster systems to anchor their refrigeration operations, even in warmer climates. Sprouts Farmers Market is among the first retailers in North America to do just that. They opened their first store in suburban Atlanta in July 2014, and when they did, they set out to prove CO2 transcritical booster systems aren’t only for cool climates.
Like many food retailers, Sprouts has historically employed more traditional refrigeration systems based on common hydrofluorocarbon (HFC) refrigerants. These HFC systems operate with what’s traditionally seen as acceptable temperatures and pressures. CO2’s low critical point temperature and high operating pressure (around 1,500 psig) are characteristically not found in traditional HFC-based refrigeration. These are the primary reasons for the reluctance to move toward CO2. But, with advances in system technology and architecture, CO2 can be a game changer for retailers seeking to improve energy efficiencies, achieve sustainability targets and cross the finish line on regulatory compliance.
Changing their refrigeration philosophy and moving to a CO2 transcritical system architecture was a giant step for Sprouts, especially for this store in the hot, humid climate of Atlanta. To pull this off, they turned to OEM partner Hillphoenix, and Hillphoenix, seeing the challenge presented by installing a CO2 transcritical booster system in a warm climate, turned to Emerson Climate Technologies.
Emerson’s E2 Facility Management System was installed to oversee the CO2 transcritical booster system. It manages nearly 50 electronic case control units and optimizes the facility’s overall energy management profile.
The E2 system helps improve performance in multiple ways:
- Controls the variable speed of the fans on the adiabatic condenser in response to operating conditions
- Optimizes compressor coefficient of performance by regulating system discharge pressures via Emerson’s high-pressure CO2 controller
- Provides complete oil management control of all CO2 refrigeration compressors
- Communicates with and captures information from individual case control units
- Provides complete control of building HVAC and refrigeration systems, and supports the retailer’s energy and maintenance reduction strategies
The E2 system also allows Sprouts operators to run diagnostics, monitor the system remotely through Emerson’s ProAct™ Service Center and, if necessary, shut down the system components before failure.
The condenser manages both low- and medium-temperature refrigeration requirements on the same system using only CO2 as the refrigerant, another unique aspect to the transcritical booster system. Running both requirements from the same condenser enhances the efficiency of the system across the store.
It’s understandable why stateside end users are hesitant to switch to CO2 transcritical booster systems. Concerns over operating pressures, maintenance levels and energy have prompted careful and steady evaluations to understand the true cost of ownership for their enterprises. Emerson technology helped ease those concerns for Sprouts. Their Atlanta-area store is operating efficiently and effectively on the transcritical system.
This blog is a summary of the article National Grocery Store Chain Makes Transition to Transcritical Refrigeration from our recent edition of E360 Outlook. Click here to learn more on our involvement with Sprouts’ Atlanta store.