With the approaching HFC phasedown, the demand for environmentally friendly cooling systems is driving chiller manufacturers to innovate. Washington-based Pro-Refrigeration, Inc., a leading manufacturer and supplier of chillers for the industrial and beverage processing market and a longtime customer of Danfoss, developed the idea of a CO2 chiller and determined that Danfoss components had the capacities and safety ratings to meet the needs of the project. The collaboration brought big dividends to a California dairy farm and ultimately, to the environment.
Since CO2 is a natural refrigerant with a GWP rating of 1, not only does it have zero impact on global warming, it also allows refrigeration systems to recover 100% – three times that of chillers using synthetic refrigerants – of the heat rejected from their systems, generating hot water at up to 200 degrees. For Pro-Refrigeration, heat recovery capability is an essential product feature, as beverage plants, dairy farms in particular, use a high amount of natural gas or propane to heat water for sanitizing and wash-down. Heat recovery technology lowers both their costs and climate impact.
The Danfoss components utilized in the CO2 chiller include the AK-SM850A system manager, AK-CC 750A case controller, AK-PC781A pack controller, as well as the CCM 20 and CCMT 30 electric regulating valves, BC 5100 pressure switches, pressure and temperature sensors, and other accessories such as AK-PS 250 power supply and GDC gas detector. All of the parts work together to monitor the cooling system, gather data from the sensors, control when the compressors cycle on and off and ensure the fans and expansion valves are working correctly.
“The Danfoss components provide the brains of the system,” explained Jim VanderGiessen, Pro-Refrigeration’s co-founder and CEO. “They keep the system running in an optimal manner.” As part of its constant monitoring and adjustment to external conditions, the system manager generates alerts and alarms, so that the facilities staff can immediately identify and address potential mechanical problems. The refrigeration control system also allows Pro-Refrigeration engineers to access the data remotely for improved customer support and troubleshooting capabilities.
A California dairy farm was a willing and eager customer for the inaugural CO2 chiller. Since installation, the milk temperature has averaged 37.1 F, whereas their previous chiller was unable to cool below 40 F. As a result, the farm was able to earn a quality bonus from milk processors and see revenue increases in the range of $1,400 to $2,800 per day.
The chiller also recovers the waste heat from the chiller system to heat the wash water, heating 3000 gallons of well water per day from 70 F to 140 F and eliminating the need to use fossil fuels (propane) as a heating source. Early results tracking indicates that the heat recovery operation is saving the farm 30 gallons of propane each day, totaling about $2,100 in savings per month.