Graduation Date

Spring 2021

Document Type



Master of Science degree with a major in Environmental Systems, option Energy, Technology, and Policy

Committee Chair Name

Arne Jacobson

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Charles Chamberlin

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Margarita Otero-Diaz

Third Committee Member Affiliation

HSU Faculty or Staff

Subject Categories

Environmental Systems


With global warming potentials (GWP) in the thousands to tens of thousands of metric tons of carbon dioxide equivalent (MTCO2e) and the possibility for substantial emissions associated with leaks of refrigerants used in heating, ventilation, air conditioning, and refrigeration (HVACR) equipment, it is important for Humboldt State University (HSU) to document and report greenhouse gas emissions (GHG) associated with refrigerant leaks.

This study has collected data on HSU’s HVACR inventory, emphasizing the refrigerant types used, the charges of the equipment (i.e., the amounts of refrigerant in the systems), and the types of equipment. The data were aggregated into a model and paired with typical annual leak rate values for the respective equipment types. The corresponding amount of refrigerant lost through annual leaks was used to estimate a range of GHG emissions.

The HSU campus likely emits between 57 and 429 MTCO2e annually through refrigerant leaks. This amounts to 1% to 5% of the total 2019 campus GHG emissions. Additionally, it is likely that refrigerated condensing units that use the refrigerant R-404a are the most significant contributor to these emissions.

As HSU progresses towards its carbon neutrality goals and as the global community takes measures to eliminate some of the refrigerants used at HSU, it is increasingly important for the university to take action to better understand and eliminate the use of high-GWP refrigerants. Given the commercial availability of lower-GWP refrigerants, it is HSU’s responsibility to determine how to reduce this portion of its environmental impact.

Citation Style



Thesis/Project Location