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Cooling campus buildings in the future will be more ozone friendly and reduce the campus’ carbon footprint by the same as taking 11,000 cars of the road for a year. This significant carbon credit flows from UMass Medical School’s decision to change out and destroy the refrigerant gas used in the campus’s cooling operations for 40 years.
“The old gas is actually a very valuable commodity, because it’s not manufactured anymore,” said David MacNeil, senior mechanical project manager at the UMMS facilities department. “But instead of selling it, we opted to have it destroyed and take the carbon credit.”
There are three large mechanical chillers at the campus power plant which provide the cold water that flows through the air conditioning systems of each school and clinical building. Two of the three chillers were installed in the 1970s and use a common industrial refrigerant called R-500, often referred to by the commercial brand name Freon (a trademark of DuPont).
The gas, which is a collection of chlorofluorocarbons (CFCs), was the global standard of the day when installed. If released to the atmosphere, however, R-500 and other CFCs cause depletion of the ozone layer and contribute to the greenhouse gas effect and its global warming potential. Because of these negative effects, it is no longer legal to manufacture CFCs, though it remains legal to recycle existing stores of the gas and sell them to operations still using them. There are, however, significant federal tax credits available to entities that agree to destroy their CFCs.
This June, when one of the aging chillers needed a total mechanical overhaul, UMMS reviewed its options and decided to replace the R-500 with a new refrigerant that doesn’t carry the same global warming potential. Specialized contractors were hired to remove the gas and ship it to a facility in Texas where it was destroyed by controlled burning.
A total of 6,050 pounds of R-500 was removed from the chiller needing repair. When that chiller is put back in service later this year the team will move to the second chiller and remove its 10,000 pounds of the gas for destruction.
Coolgas, the company hired for the R-500 project, is paying UMMS $18 per pound for the gas—a total of $288,000 which will cover about half of the cost of repairing the chiller and installing the new refrigerant. Coolgas calculations show that destroying 16,000 pounds of R-500 reduces potential atmospheric CO2 by 52,000 metric tons, which equates to taking some 11,000 cars off the road for one year.
“The new gas we will use is much better for the environment, and it has a better safety profile for the plant operations,” MacNeil said. “So it’s a win all around.”