NATURAL REFRIGERANTS FOR RAILWAY HVAC

Reducing the environmental impact of railway HVAC requires looking beyond refrigerant GWP alone. Energy consumption throughout the system's lifetime also plays a major role.

This is why Greenair combines natural and lower-GWP refrigerants with technologies designed to improve energy efficiency, reuse existing assets and support long-term HVAC performance.

This broader approach considers Total Environmental Warming Impact (TEWI), taking into account both direct emissions linked to refrigerant GWP and charge, and indirect emissions resulting from energy consumption. Greenair's flexible HVAC architectures also support the transition of existing fleets towards lower-GWP refrigerants.

NATURAL REFRIGERANTS

Natural refrigerants offer a lower-GWP, PFAS-free alternative to conventional refrigerants, helping railway operators reduce the direct climate impact of HVAC systems and prepare for evolving regulatory requirements. Greenair works with two key natural refrigerant technologies for railway applications: R290 (propane) and R744 (CO₂).

• Propane: R290, GWP 0.02 R290 combines an ultra-low GWP with high thermodynamic efficiency. As a PFAS-free natural refrigerant, it offers a strong option for reducing the environmental impact and energy requirements of railway HVAC applications
• CO₂: R744, GWP 1 R744 is a PFAS-free, natural and non-flammable refrigerant with very low GWP and broad availability. Its thermodynamic properties make it particularly relevant for heat-pump applications, supporting efficient heating and cooling across demanding operating conditions.

EFFICIENCY GOES BEYOND THE REFRIGERANT

HVAC systems can account for up to 30% of a train's energy consumption. Reducing their environmental impact therefore means addressing not only the refrigerant itself, but the efficiency of the complete system.

Greenair combines complementary technologies to optimize heating, cooling and ventilation according to actual operating needs, helping reduce energy consumption while maintaining thermal performance and passenger comfort.

• Heat pump technology — Low-energy heating performance
• Advanced heat exchanger design— Maximized thermal efficiency
• High-efficiency fans — Lower energy consumption
• Smart capacity control — Only the capacity required, when needed
• Demand-controlled ventilation— Energy-efficient fresh air supply

Together, these technologies help reduce the indirect emissions associated with energy consumption, supporting a more comprehensive approach to railway HVAC efficiency.

MODERNIZE PERFORMANCE, EXTEND SYSTEM LIFE

Existing HVAC equipment can evolve with changing environmental and operational requirements. Merak can tailor system upgrades to integrate lower-GWP refrigerants and energy-efficient technologies while making use of existing assets wherever technically relevant.

This approach can help operators improve efficiency, reduce energy and maintenance costs, extend equipment service life and support compliance with evolving emissions requirements.

SUSTAINABLE, FULL-SYSTEM RAILWAY HVAC SOLUTIONS

As part of Naturail, Greenair works within a broader approach to railway HVAC modernization — three complementary technologies, one direction: moving railway HVAC forward.