Executive Summary
Rather than treating captured CO₂ purely as cargo awaiting depot offload, this publication describes two onboard uses: a closed-loop R744 thermal system for cooling and heat-pump heating, and a tubing-and-sensor network for rapid, residue-free fire suppression in electrical, pantry and brake zones. Both uses are illustrative design concepts based on established CO₂ refrigeration and fire-suppression principles, pending detailed validation.
Capture, store, reuse
Approximately 100 kg of CO₂ is targeted for capture per coach per trip, stored onboard across roughly five 20 kg cylinders, before being offloaded and processed at depot for downstream utilisation.
The R744 thermal loop
CO₂ (R744) is a well-established, low-GWP refrigerant. Used as the working fluid in a closed loop across the coach, it is projected to provide efficient cooling in summer and heat-pump heating in winter, targeting roughly a 25% reduction in net HVAC energy demand.
This publication describes conceptual frameworks and proposed architectures. Where quantitative figures appear, they are engineering projections intended for planning and are subject to experimental validation.
A CO₂ fire-safety network
A parallel tubing-and-sensor network routes CO₂ to fire-prone zones — electrical panels, pantry areas and brake systems — enabling rapid, residue-free suppression without the cleanup and equipment damage associated with conventional agents.
Glossary
References
References point to established engineering disciplines and public frameworks, not fabricated citations.
- Established principles of CO₂ (R744) refrigeration cycles
- General CO₂ fire-suppression engineering practice
Suggested Citation
TransO2 Engineering Team (2025). Onboard CO₂ Utilisation: From Capture to Fire Safety. TRN-003, v1.0.
About TransO2
TransO2 is an Environmental Infrastructure Technology company developing integrated engineering concepts that reimagine transportation assets as intelligent environmental platforms. Through systems engineering, sustainability, digital technologies, and modular design, TransO2 explores new approaches to environmental value creation across mobility and infrastructure.