Abstract
Direct air capture (DAC), which captures CO2 from ambient air, is a critical technology to reduce greenhouse gases in the atmosphere in order to avoid climate disasters. Due to the relatively low concentration of CO2 (400 ppm), a large amount of air needs to be moved through DAC devices, which requires lots of energy. Currently, DAC technologies are deployed mainly in centralized systems and require extensive infrastructure and initial capital cost. A potential solution is to utilize existing infrastructure for DAC. In this study, we propose a distributed DAC system that utilizes existing commercial rooftop heating and air conditioning (HVAC) units to capture CO2 from the air. There are approximately 15 million such units already installed on commercial buildings in the United States, and they move a large amount of air every day. Adding DAC functionality to these units will significantly reduce the cost of infrastructure and operation. A modular approach was used to introduce DAC into a rooftop unit. Modules filled with triethylenetetramine-functionalized polyacrylonitrile sheets were developed and installed on the condenser coil side of the rooftop unit. The rooftop unit with DAC functions effectively captured CO2 from the air, and the addition of the DAC modules had little effect on the unit's original functionality. A preliminary techno-economic analysis was also conducted, and the results potentially suggest that utilizing existing commercial rooftop units for carbon capture is a feasible approach to reducing greenhouse gases.
| Original language | English |
|---|---|
| Pages (from-to) | 937-949 |
| Number of pages | 13 |
| Journal | Environmental Science: Advances |
| Volume | 3 |
| Issue number | 6 |
| DOIs | |
| State | Published - May 6 2024 |
Funding
This research was supported by the DOE Office of Fossil Energy and Carbon Management (FECM) and used resources at the Building Technologies Research and Integration Center (BTRIC) and Manufacturing Demonstration Facility (MDF), DOE Office of Science User Facilities operated by the Oak Ridge National Laboratory. The authors would like to acknowledge the assistance of Brian Goins, Anthony Gehl, and Robert Nettles in the setup and performance of the testing. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. The DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).