R-507 is a hydrofluorocarbon (HFC) refrigerant that is non-ozone depleting and is considered environmentally friendlier than chlorofluorocarbon (CFC) and HCFC refrigerant products. The production and use of HCFC R-22 is being phased out in accordance with the Montreal Protocol, and refrigeration-dependent industries continue to retrofit systems using environmentally friendlier products such as HFC refrigerants. The Montreal Protocol was ratified in 1989 and was implemented in the U.S. through Title VI of the Clean Air Act, which is monitored and enforced by the EPA.
A RACEY RETROFITRace Engineering of Garden Grove, CA, spearheaded the retrofit project. In business for more than 15 years, Race specializes in the installation and service of large refrigeration systems. Race welcomed the challenge, relying on the company's wealth of industry experience to see the project through to its successful completion. The project was a collaborative effort among Race, RSD-Total Control, and Chill-Tek Incorporated.
RSD-Total Control of Lake Forest, CA, is a regional wholesaler of refrigerants, refrigeration and air condi-tioning components, and control systems. In operation since 1933, RSD-Total Control is a major distributor of Honeywell refrigerants and is said to have purchased the first cylinder of Honeywell's Genetron R-22 more than 50 years ago.
Headquartered in Manhattan Beach, CA, Chill-Tek, Inc. is an EPA-certified refrigerant recovery and reclamation company. It provides a range of technical services such as recovery of low- and high-pressure refrigerants, on-site cylinder evacuation, refrigerant and oil analysis, and mixed refrigerant disposal. Chill-Tek serves a broad customer base that includes contractors, wholesalers, and municipalities.
"This project took the experience and expertise from all companies involved," said Gary Lawson, CEO of Race Engineering. "This was a massive retrofit, but the collaborative effort made it a success."
BLAST FREEZING TO BULK COLD STORAGEFor the retrofit, Race had to account for several types of equipment used by the food processor in its production facility: a Chester Jensen potable water chiller, Mycom & Frick screw compressor packages, Frigid Coil evaporators, Baltimore AirCoil Condensers, and RVS Vessels. The equipment performs a variety of functions that are vital to the food production process, including blast freezing and bulk cold storage at this 300,000-sq-ft plant, which is approaching 60,000 gal of storage capacity
Race was tasked with completing the retrofit with minimum production downtime. To accomplish this task, they first planned to evacuate the Alkylbenzene oil charge, replacing it with Polyol Ester oil to provide proper solubility and lubrication when paired with an HFC refrigerant. According to Lawson, Chill-Tek was instrumental in performing the oil change while the system was still operating on R-22. This contributed greatly to minimizing production downtime.
They first pumped down the refrigerant into the in-line liquid receivers during the weekend of the conversion. Chill-Tek was then able to recover more than 24,000 lbs of R-22. While the recovery was underway Race installed larger liquid lines and replaced the thermal expansion valves.
To complete the retrofit, Race charged the system with 27,200 lb of Honeywell Genetron® AZ-50® R-507 refrigerant. The technical team completed the retrofit in just 72 hours.
"We have experienced compressor capacity increases, along with motor rating increases, which required load-limiting control modifications," said Lawson. "We also expect the food manufacturer will experience oil separator gas velocity increases."
Race evaluated a number of potential refrigerant products for the retrofit, including R-404A and R-417A, tak-ing into account issues such as flooded evaporators used in the system. Race selected R-507 because it is an azeotrope (a blend that acts as a pure fluid), and because it offered the cooling capacity and efficiency necessary to meet the critical needs of the customer.