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Sustainability Benefit

One of the biggest concerns in the industry today is that of sustainability. As the regulatory structure and consumer attitudes change, customers have moved increasingly toward so-called “greener” operations that save energy and reduce their carbon footprint. With the advent of various global initiatives and conventions such as the Kyoto Protocol and other agreements, the supermarket industry has become an easy target due to its high leak rate (an average of about 25% across the industry) and high global warming numbers for its refrigerants. This has resulted in, among other moves, the phase out of some refrigerants (R-22, for instance) and the higher cost and taxing of others — as of Fall 2008, for instance, the tax on R-404A in Denmark was over $32 per pound. In the U.S., regulatory compliance is expected to only get stricter. Customers are going to have to find alternatives to traditional approaches and distributed systems offer one of the most effective paths to greater sustainability.

Distributed systems use smaller compressors. Because suction groups are more closely matched, very little excess capacity is required to be designed into the system. Smaller, more energy efficient compressors can be used to provide only the capacity needed for each closely matched suction group.

While there are advantages in sustainability with distributed systems over traditional systems, the greatest reductions in carbon footprint and energy use with distributed systems come when they are combined with secondary refrigeration (see “Traditional Versus Secondary Supermarket Refrigeration,” Contracting Business, December, 2008, p. 50; or contractingbusiness.com/refrigeration/content/refrigeration_primary_secondary/). Distributed systems that employ both medium-temperature glycol cooling and low-temperature CO₂ cooling enable customers to achieve some of the lowest refrigerant charge values possible for whole stores.

Installation Requires Separate Controllers

Each unit typically has its own controller and its own wiring to and from the cases to which it is connected. Structural requirements also include adequate support for each unit. Whereas a traditional system contained in a roof-mounted machine house requires support for just the single house and attached condensers, each unit of a distributed system must have its own. This requirement can add up to more steel.

Those concerns not withstanding, customer experience suggests that another benefit of more evenly matched loads is potential energy savings. Three to five percent reductions in energy use have been observed by some customers. Combined with lower refrigerant charges and leaks, these energy savings contribute to reduced carbon footprints and greater sustainability. The consumer attitudes noted above lead shoppers to stores that can make these claims. In the case of distributed systems, profitability and sustainability go hand and hand.

Bill Katz is a technical writer and course developer for the Hill PHOENIX Learning Center. He has written and developed training for the refrigeration and information technology industries. He can be reached at william.katz@hillphoenix.com.