OFG said it began experimenting with CO2 refrigeration systems in 2010.

“Recycling, sustainable seafood, reusable bags, energy-efficient stores, and our efforts to be the No. 1 supporter of local products and producers are just some of the ways we show our commitment to sustainability every day,” said Carmen Churcott, vice-president, OFG.

“We chose a transcritical CO2 booster system because it’s 100 percent HFC-free,” said Ralph Thiel, director, store planning and construction for OFG. “We’ve seen a number of synthetic refrigerants phased out over the years, and with its high global warming potential, we expect that eventually the current HFCs will be phased out, too. CO2 transitions us to a natural refrigerant that we can live with in the future.”

The transcritical CO2 booster system utilizes CO2 as the only refrigerant covering both medium-temp and low-temp loads.

According to advocates, CO2 has a high temperature heat of rejection, making it ideal for hot water heat reclamation applications and efficient hot gas defrosting.

According to an announcement from Hill Phoenix, “CO2 systems operate under much higher pressures than conventional HFC-based systems. Many CO2 systems require steel piping throughout and carry a higher risk of pressure-related system breakdowns. The Advansor system eliminates those concerns by perfecting the use of pressure-reducing valves so that everything inside of the store operates under lower pressure, as it would with an HFC-based system.”

Contractors can use copper piping and realize that the system maintains pressures within a range normally found in traditional DX systems, the manufacturer said. Urban Fare Express does have a back-up auxiliary condensing unit on a back-up generator in case of power failure.

The smaller condensing unit cools the CO2 and keeps the pressure low to prevent the loss of CO2.

So why haven’t more retailers made the switch? According to the Hill Phoneix statement, “CO2 systems are still relatively new to supermarket applications. As companies like OFG demonstrate the advantages of CO2, industry acceptance will no doubt increase.”

“Our company is dedicated to CO2 in all new stores in urban settings and any location where there is a population base with enough tradesmen to be trained on CO2 technologies,” said Thiel.

On The Increase

At the same time, advocates of the technology said 2013 will see more retailers in the United States using transcritical CO2 supermarket systems.

That was confirmed by speakers and participants at ATMOsphere America 2012 — the Business Case for Natural Refrigerants conference held in Washington D.C. in late spring. It was said that first installations are expected in the fall, once the technology receives UL approval.

Talking about transcritical systems, Scott Martin of Hill Phoenix said, “System investment cost is another barrier that the industry faces, as there are no economies of scale yet.”

But it was noted that as natural refrigerants become mainstream they make business sense. And in fact, in his speech at the conference, Predrag Hrnjak of the University of Illinois noted, “In vapor compression systems today, I believe that ammonia, hydrocarbons, and carbon dioxide are, at this point, probably the only serious contenders to become mainstream options.”

Another Project

Another stateside project related to natural refrigerants was Source Refrigeration & HVAC Inc., who announced that it was chosen by SuperValu Inc., one of the nation’s largest grocery companies, as a team member on the company’s first all-natural refrigerant store project: a remodel of an Albertson’s® grocery store in Carpinteria, Calif.

“This project is a testament to SuperValu’s commitment to natural refrigerants and sustainability,” said Richard Heath, director of energy innovations and projects for SuperValu. “We selected Source because of their extensive experience in planning, phasing, installing, executing, and sustaining mission-critical refrigeration and HVAC systems,” Heath added. “Source’s commitment to system optimization and energy efficiency is very much in line with SuperValu’s overall sustainability efforts.”

According to Heath, Source was critical to the majority of key project stages, including the design/review process, project phasing and scheduling, technology implementation, installation, operational review and validation, and operational/functional sustainability.

The grand re-opening of Albertson’s took place in July 2012.

Ammonia Perspective

With the EPA’s Whitman touching on use of ammonia in at least one supermarket in the United States in the near future, the feasibility of such a refrigerant in such an application is based on research and track records being established in Europe.

At the International Institute of Ammonia Refrigeration’s annual conference in 2012, attention was paid to the reality in a paper presented by Caleb Nelson of CTA Architects, Missoula, Mo.

He admitted, “In the U.S. supermarket industry, misconceptions of ammonia (R-717) and the codes that govern it, coupled with a lack of knowledge pertaining to the systems, serve as major hurdles that will need to be cleared before ammonia can be accepted as a viable alternative to traditional halocarbon refrigerants.”

He described some of the approaches such as using a liquid overfeed system or a low-pressure receiver system.

“Supermarket owners that look to apply ammonia should be confident in the fact that a properly implemented system can be extremely safe and efficient. Beyond this, there are no deterring code restrictions preventing its use in the majority of the United States. Designers should also be reassured by the fact that utilizing ammonia commercially doesn’t require the reinvention of the wheel. Ammonia systems have been used around the world for many years in various types of industries and applications — and more recently — in supermarkets. Although initial system cost and technician training are hurdles that are indeed real, it is comforting to know that they are only temporary and that they are no different from the hurdles that CO2 and other ‘new’ technologies are facing.”

Publication date: 9/3/2012