The Yale Refrigerants Initiative (YRI), founded by Yale College student Tilden Chao in 2020, is recommending the use of isobutane (R600a) as a climate-friendly alternative to HFCs for student dorm mini fridges.

Over the past year, Tilden – who is studying economics and pursuing a certificate in Yale’s Energy Studies Multidisciplinary Academic Program – has been working alongside seven fellow undergrads to catalogue the refrigerants being used in equipment across the university. From campus dining halls and power plants to laboratory equipment and dorm room refrigerators, a full inventory of Yale’s refrigerants has been compiled.

In addition to gathering data on all refrigerants being used on campus, YRI is also committed to easing the transition from HFCs to sustainable refrigerants, offering recommendations on how to phase down and manage HFCs in line with the American Innovation and Manufacturing (AIM) Act.

For example, the YRI, which started with a US$25,000-grant from Yale’s Office of Facilities’ Student Green Innovation Fund, has produced a buying guide to help students make climate-friendly choices when purchasing mini fridges for their dorm rooms. All recommended products are Energy Star certified and use natural refrigerant R600A.

Unaware of refrigerants and their impact on our climate, Tilden learned about the mitigation potential of better refrigerant management and the adoption of alternative refrigerants via Project Drawdown.

“I started researching refrigerant emissions and realized that even at the time, in 2018, there were technologically viable solutions to the problem,” said Tilden. “With the information that we’ve gathered here on campus, we can develop new, targeted solutions for a problem we previously didn’t know existed at this scale,” he continued. “Refrigerants are an unexpectedly exciting and powerful solution to climate change.”

“Refrigerants are an unexpectedly exciting and powerful solution to climate change.”

Tilden Chao, Yale College

Yale’s transition to low-GWP refrigerants

According to a recent news story on the Yale Sustainability website about Tilden and the YRI, refrigerant leaks were thought to be responsible for less than 2% of the university’s reported GHG emissions. However, Tilden’s investigation, which had a wider scope than Yale’s own reporting, uncovered data showing that refrigerants in fact make up 4.3% of the university’s GHG inventory. 

“As long as we have an incomplete understanding of the refrigerant problem, we’ll never reach true net zero,” said Tilden. “We can’t manage what we can’t measure.”

If Yale is to achieve its goal of being carbon zero by 2050, leaks need to be minimized and low-GWP alternative refrigerants need to be adopted. According to Julie Paquette, Director of Engineering and Energy Management in Yale’s Office of Facilities, this is particularly important as the university transitions toward refrigerant-based electric heating and cooling systems.

“Heat pumps represent a really important aspect of Yale’s decarbonization strategy,” said Paquette. “As heat pumps are adopted to both cool and heat buildings, we will increase the amount of refrigerant that we have on campus and the likelihood of leaks.”

As the Yale Sustainability article points out, “while there’s no zero-leak refrigerator, there are ways to minimize leaks as well as alternative refrigerants that pollute far less when they do leak.”

Some of Tilden’s suggested solutions include implementing detection systems to bring attention to leaks, recycling equipment and reclaiming refrigerants for reuse and retrofitting equipment with lower-GWP refrigerants.

According to Paquette, Yale will be replacing high-GWP refrigerants with lower-GWP alternatives. They are also exploring different ways of monitoring and repairing equipment to minimize refrigerant leaks and their impact.

This project is the first of its kind in the U.S. Tilden has shared his research as a best practice with other universities in the Ivy Plus Sustainability Consortium, with the aim of easing the HFC phase down for other institutions of higher education.

Tilden was recently honored at Yale’s annual State of Sustainability Awards on Earth Day.

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