Read on to know more about the first round of technology case studies selected for ATMOsphere America 2014's Industrial refrigeration session...

• Reducing Ammonia Charge Below 10,000 lbs in a Newly Constructed Public Refrigerated Warehouse by Bruce I. Nelson, Colmac Coil Manufacturing

Traditionally, industrial ammonia refrigeration systems have used pumped recirculation to distribute refrigerant to evaporators. This type of system while offering a number of operational benefits also uses the maximum possible system charge, in the range of 25 to 30 lbs/TR. New Low Charge DX Ammonia technology allows for the use of direct expansion (DX) to reduce the ammonia charge in evaporators by as much as 50 times and system charge to the range of 5 to 6 lbs/TR. A new 400,000 sq ft Public Refrigerated Warehouse has been built in the Midwest USA, which utilizes this new Low Charge DX Ammonia technology to achieve over 1,000 Tons of refrigeration with only 7,000 lbs ammonia on the site. By comparison a traditional pumped ammonia system would require approximately 30,000 lbs of ammonia to operate the system. Most of the reduction in the ammonia charge takes place in the occupied spaces of the facility which reduces the risk of exposure to ammonia for both workers and products. The case study will review system specifications, ammonia charge reduction, first cost comparison, and lessons learned.

• Comparative Energy and Emissions Performance of a Natural Refrigerants System (CO₂/NH₃) versus an HFC System (R-507) in an Industrial Refrigerated Warehouse by Rafael Castillo, VaCom Technologies

Extensive measured performance data was collected for a large industrial carbon dioxide and ammonia cascade refrigeration system, as part of an earlier emerging technologies project funded by PG&E to demonstrate the energy efficiency, safety, and regulatory benefits of the Cascade CO₂/NH₃ system compared to a more conventional refrigeration system. The purpose of this 2014 case study was to subsequently compare the actual measured efficiency of the Cascade CO₂/NH₃ system against the calculated efficiency of an HFC-507 refrigeration system, operating at the same refrigeration loads and process temperatures. The original project included field installed instrumentation and data acquisition equipment to monitor and evaluate the real-time performance of the refrigeration plant in a public refrigerated warehouse (PRW) in California.