Efficient HVAC Systems Improve Shopping Experience
HVAC energy usage plays a large role in supermarket budgets, and today’s systems are significantly reducing that usage while maintaining an inviting store environment.
“We look for a system that excels at dehumidification, or reducing the amount of humidity in the store,” says Karen O’Shea, of Keasbey, N.J.-based Wakefern Food Corp. “Our refrigeration cases are designed to operate at very specific temperatures and relative-humidity environments, so it’s important for us to control humidity in stores.”
The primary system in Wakefern’s ShopRite stores employs a regenerative drying technology that’s “very efficient when it comes to heating and cooling the store,” O’Shea notes. “The secondary systems we choose are high-efficiency units specifically designed for humidity control. ShopRite works hard to apply sustainable solutions in an effort to shrink our environmental footprint.”
ShopRite stores usually upgrade their HVAC systems at the end of a typical 15-year life cycle, according to O’Shea.
Including variable-speed fan control as a standard would help improve HVAC efficiency, O’Shea asserts. “Tuning the speed of the fan while heating or cooling, and slowing the fan when not heating or cooling, can significantly reduce energy consumption when combined with other technologies to ensure proper ventilations,” she says.
Save More Food Markets Inc., in Minocqua, Wis., looks for a return on investment in an HVAC system to be as short as possible for “a noticeable savings on the monthly energy cost,” says President Jim Gauden. Save More has been updating its HVAC by “adding newer units to better control the front of the store,” he observes. “This conditions the air getting into the store better, to keep the older unit on the back half from running hard.”
With the older units next on the upgrade list, Gauden notes that Save More evaluates its system twice yearly and has regularly scheduled maintenance to uncover potential problems before they happen.
“This also helps us better determine the life of existing units,” he says, “but overall upgrades usually happen when absolutely needed or the old unit is simply costing too much to operate.”
Better air circulation and more efficient fans would improve today’s systems, Gauden suggests.
According to Danny Miller, president of Transformative Wave at Kennesaw, Ga.-based Emerson Commercial & Residential Solutions, there are new HVAC controls that allow grocers to retrofit an existing system quickly, easily and cost-effectively.
“These new advanced rooftop-unit controls help save energy, reduce maintenance costs, ensure indoor air quality and maintain proper building-pressure control, all without compromising customer comfort,” he says.
Miller adds that Emerson’s recent investment in a minority interest in Transformative Wave brings to customers the latest ARC technology in the Catalyst product line, a packaged system with unique algorithms that’s a HVAC energy-efficiency upgrade.
“Refrigeration often takes priority over HVAC for many supermarket operators,” he notes. “Replacement is often determined based on the age of the assets or increased repair expenses.”
This belief is being challenged, according to Miller, by the advanced fault detection and diagnostic capabilities of Catalyst solutions. This knowledge helps prevention of critical breakdowns and lets systems run less, allowing supermarkets to extend the life of current HVAC systems and saving thousands of dollars in capital costs.
The Catalyst Lite product, he continues, is a low-cost path to HVAC energy savings and an intelligent variable-frequency drive (VFD) that includes a supply air sensor that goes much further than a typical VFD.
“Emerson has recently introduced the ProAct Alerts Mobile App that works with the company’s ProAct Services,” Miller adds, “assisting retail facility managers, store managers and contractors in quickly and effectively responding to critical HVAC, refrigeration and building alerts.”
LED lighting upgrades and enclosed refrigeration cases are changing HVAC needs to require variable-speed compressor control and variable-speed fans, he says.
At Source Refrigeration and HVAC, in Anaheim, Calif., VP and Chief Engineer Bryan Beitler observes, “Many retailers moved away from central air handlers to package equipment years ago, and it seems they are now fine-tuning and refining this process.”
Still, he points out that HVAC infrastructure doesn’t get updated with the same frequency as refrigerated cases, and that, typically, upgrades occur when there’s a remodel or there’s an end of life of HVAC equipment. For HVAC systems, upgrades occur between 10 and 20 years, while refrigeration remodels may occur in the seven-to-10-year range, Beitler notes.
He says that, as a contractor, Source’s “products” would include items such as controls upgrades and commissioning of the HVAC system, and “we also offer HVAC-specific preventative-maintenance programs that are focused on ensuring the HVAC system is fully functional and efficient.”
Beitler adds that side benefits might be the uncovering of the need for upgrading outdated or inefficient systems, or correcting system design flaws.
“The cost of utilities continues to be a challenge for the HVAC designer and the retailer,” Beitler admits, “spurring additional innovation in developing a more energy-efficient total environment. The importance of the HVAC designer, working hand in hand with the refrigeration designer and building architect to achieve a unified design, cannot be underscored enough.”
New Day Dawning
With supermarkets using four to five times more energy per square foot than any other type of commercial building, solar energy is starting to play a major role in offsetting grocery store energy loads, says Robert W. Martin, director of field operations at Siemens Building Technologies Division, in Buffalo Grove, Ill.
“Federal tax incentives and local utility rebates are making it very attractive for grocery chains to purchase solar to help offset the large energy demand loads that grocery stores have today,” he notes.
Siemens works with HVAC manufacturers in controlling and monitoring their installed items in grocery stores. Currently, the company has energy management systems (EMS) in more than 1,600 grocery stores.
Refrigeration, which accounts for 53 percent to 65 percent of a store’s energy load, is the priority, Martin stresses, and issues surrounding HVAC equipment, which accounts for 9 percent to 20 percent, are handled in a reactive manner. “Properly maintained rooftop units tend to last 15 to 17 years, which should allow ample time for the facility team to have a plan for replacements and upgrades,” he says.
Several refrigeration control companies are teaming with EMS companies to merge the best cloud-based solutions with analytics and years of experience in managing energy, Martin adds, identifying it as a trend that will eventually migrate to HVAC.