“We started using glycol three or four years ago in the stores and have become more and more comfortable with glycol as a refrigeration medium,” said Paul Collette, project manager, real estate and construction for Longo’s Supermarkets. “We also like the green aspects, which lower the amount of refrigerant use.”
Until recently, the options for refrigerating large commercial and industrial facilities (i.e., cold storage warehouses, distribution centers, and ripening facilities) have been mostly ammonia-based and synthetic refrigerant systems. For some involved in refrigeration equipment decisions, there is a concern over code requirements on ammonia and the cost of full-time on-site engineers. When it comes to synthetic refrigeration issues, the issue might be the large amounts of refrigerants.
Over the years, glycol systems have become an alternative to ammonia and direct expansion for commercial and industrial operations. They can be deployed in various configurations ranging from machine rooms and mechanical centers to distributed system enclosures for retail applications. Longo’s chose a mechanical center configuration that eliminated the need for a conventional compressor room and freed more warehouse space for its intended purpose — warehousing product.
The manufacturer’s mechanical centers are self-contained, factory built, and delivered to the customer pre-wired, pre-piped, and pre-assembled. The “plug-and-play” format reduces installation costs when compared to more traditional systems.
According to officials at Hill Phoenix, glycol systems in a warehouse application allow for larger but fewer evaporators/air-units. From a design standpoint, the approach employs a parallel or multi-compressor system, and redundancy is built-in.
In the glycol-based configuration, 100 percent of the evaporator/air-unit is utilized because the air unit is fully flooded. Longo’s retail stores have experienced substantially reduced pull-down times, and similar performance is expected in the warehouse, it was reported.
Combined, the two warehouse units provide 185 tons of refrigeration for more than 56,000 square feet of space. Each of the units has two medium-temperature racks and two glycol pump stations. A conventional low-temperature rack is also included in one of the units.
Furthering the energy efficient benefits of the system — and earning Longo’s a LEED certification for its head office and distribution center — the company is recycling waste heat from the refrigeration system racks. Waste heat is used to heat glycol, which is then circulated through pipes underneath the freezer to keep the ground from freezing and heaving. The same waste heat process is used to pre-heat air for the office space.
Publication date: 01/09/2012