All Systems Go
Food retailers spend more than $4 per square foot annually on energy, according to Energy Star, with a large portion of this expenditure for HVAC (heating, ventilation, and air conditioning) systems. This fact is noted by Greg DuChane, retail-restaurant vertical market leader at Davidson, N.C.-based Trane, who says that for an average-sized supermarket of 50,000 square feet, this equates to more than $200,000 in annual energy costs and 1,900 tons of carbon dioxide emitted into the atmosphere.
Advances in HVAC systems are aimed at reducing those figures.
“The introduction of variable-speed technologies in light commercial rooftop units — 3 to 25 tons — provides improved energy savings, dehumidification and moisture control,” notes DuChane. “Previously, variable-speed technologies were only available in much larger units. The variable-speed technology matches the HVAC unit’s capacity to the store’s varying demand, which is based upon numerous factors that include customer trafic, building occupancy and heat-emitting equipment. By adjusting speed to meet the demand, this HVAC system affords the store greater efficiency and energy savings.”
The integration of equipment controls is another advance, according to DuChane, who explains that a building automation system (BAS) allows for precisely controlled store conditions, which prevents product damage and spoilage, and enables additional energy management solutions.
Trane offers light commercial unitary rooftop units that use variable-speed technology for fans, compressors and condensers. The HVAC systems also provide interoperability so they can communicate with other building systems like lighting and security.
DuChane anticipates the continued adoption of dedicated outside-air strategies and expanded use of variable-speed technology across all HVAC platforms.
Benefits of VRF
Dennis Cobb, senior director, national accounts at Mitsubishi Electric Cooling & Heating, in Suwanee, Ga., says his company has educated supermarket architects and engineers on the benefits of variable refrigerant flow (VRF) in store designs.
“These benefits are most obvious in areas that have proven cumbersome or challenging to properly condition with traditional HVAC systems, such as pharmacy areas, offices, and training or break rooms,” he notes, adding that VRF solutions offer increased energy savings during part-load conditions, and that Mitsubishi Electric’s VRF systems are designed to vary their capacity to meet a space’s exact conditioning demands.
“The unit’s inverter-driven compressor automatically modulates its speed to provide the exact amount of conditioning needed to cool and heat the space,” he says, “rather than overshooting the desired temperature and turning of altogether once meeting the demand. This technology saves energy and money.”
With each generation and update to Mitsubishi systems, continues Cobb, benefits like smaller unit size and more efficient performance are added.
Additionally, he’s observed smarter HVAC systems meeting the needs of each facility. “More frequently, we are seeing urban renovations where existing buildings are being purchased and repurposed into supermarkets,” says Cobb. “Our technology works well in these scenarios, because of the minimal impact on the structures versus other traditional HVAC technologies.”
Keeping it Together
Paul Hepperla, director, new solutions development at enterprise product management for Kennesaw, Ga.-based Emerson Climate Technologies Retail Solutions, points out that recent advances in grocery refrigeration have also led to advances in supermarket HVAC systems.
“Doors on refrigerated grocery cases and air management systems are solutions that improve the shopper’s experience and comfort level,” he notes, “as well as help the HVAC system operate at the ideal temperature.”
Hepperla points out that another item that affects supermarket HVAC is dehumidification, and that removing moisture from the air allows retail HVAC and refrigeration systems to work better while also improving shopper comfort.
A third advance he highlights is the integration of all retail facility systems. “Unlike a commercial building, where HVAC systems are separate and distinct from lighting,” he explains, “the HVAC, refrigeration and lighting systems can be integrated through a facility management system, for improved control and visibility across all equipment. If a retailer is only monitoring the temperatures in food cases, they are missing out on the potential efficiencies and gains from also monitoring their HVAC systems.”
According Hepperla, technology solutions for food retailers incorporate monitoring and facility controls for HVAC systems, as well as connectivity throughout a store to control HVAC, refrigeration and lighting systems, as well as visibility and monitoring throughout an entire chain of stores, for facility insights to improve operational efficiency.
“Displacement ventilation is on the horizon for retailers,” he predicts, explaining that a floor-level diffuser the length of a wall or a refrigeration case pushes a tremendous amount of air out at low velocity so that the air pools out onto the store floor, creating a chimney effect that takes the warmer air up and above shoppers, while the cooler air at floor level allows the refrigeration equipment to operate more efficiently and maintain a comfortable shopping environment.
Dan Kubala, director of business development at Siemens Retail & Commercial Systems, in Austin, Texas, points out that managing HVAC systems has been advanced by two key technology enablers: enterprise analytics and data integration.
“Enterprise analytics refers to cloud-based systems that automatically monitor HVAC performance over time to provide an indication of that unit or site’s operation, in comparison to the overall portfolio,” he explains. “This allows facility managers to become more proactive in managing a limited repair and maintenance (R&M) budget, focusing on the highest-impact problems first.”
Kubala adds that data integration refers to the ability of information produced by one enterprise application — in this case, the energy management system (EMS) — to travel seamlessly to another enterprise application — in this case, the grocer’s facility maintenance or work order dispatch management system. “Through the use of APIs — application program interfaces — automated system-to-system communication is possible,” he notes, “facilitating improved HVAC R&M management while reducing administrative costs.”
Taken together, these trends allow grocers to reduce R&M budgets by 10 percent to 15 percent, according to Kubala, on top of any energy savings from the EMS, while simultaneously improving the customer experience.
“We see technology advancing so that enterprise analytic systems will not only be able to remotely detect HVAC problems,” he concludes, “but they will be able to automatically take steps to resolve issues.”
“If a retailer is only monitoring the temperatures in food cases, they are missing out on the potential efficiencies and gains from also monitoring their HVAC systems.”
—Paul Hepperla, Emerson Climate Technologies Retail Solutions
“We see technology advancing so that enterprise analytic systems will not only be able to remotely detect HVAC problems, but they will be able to automatically take steps to resolve issues.”
—Dan Kubala, Siemens Retail & Commercial Systems