Thermo King unveils new bus HVAC heat pump with natural refrigerant

Thermo King®, a leader in transport temperature control solutions and a brand of Trane Technologies, unveiled today the new Athenia™ MkII heat pump with R-744, an environmentally friendly, natural refrigerant. The new heating, ventilation and air conditioning (HVAC) technology for buses, presented today at the IAA Transportation 2022 show in Hannover, Germany, has been designed specifically for electric and hybrid buses and optimized to deliver passenger comfort and sustainable operation with market leading performance.

“At Thermo King we are designing the bus solutions to define the today and future of sustainable passenger transport,” said Peter Hansen, product leader for Marine, Rail and Bus at Thermo King. “Thermo King develops the technologies together with and for the leading bus manufacturers, tailoring them to their needs and aiming to address the importance of sustainable transportation, rapidly increasing traffic congestion, air pollution and noise. Introducing new HVAC heat pumps with the environmentally friendly R-744 refrigerant we take another step forward in that journey.”

The R-744, often named CO2, is a natural, non-toxic, non-flammable and non-ozone-depleting refrigerant with global warming potential (GWP) of just 1. Thanks to its capabilities, the new Athenia™ MkII R-744 heat pump has been optimized to offer maximum passenger comfort not only during the summer months when cooling is required, but also during the coldest winters – with no need for additional heaters or boilers. The unit is capable of operating in heating mode in ambient temperatures as low as -25°C and deliver cooling when the temperature is as high as +50°C.

The new Athenia™ MkII R-744 heat pump is an “all-in-one” rooftop unit optimized to keep the driver and passengers at the right comfort level with heating, cooling and fresh-air control. Simultaneously the unit protects the bus driveline batteries by providing cooled or warmer water to condition them during charging and discharging. The integrated Battery Thermal Management System optimizes overall energy use, ensuring high coefficient of performance (COP) levels of the system and reducing lifecycle costs. The “all-in-one” unit can also utilize waste heat from other sources in the vehicle to further optimize energy usage and contribute to passenger comfort.

“For Thermo King Bus HVAC it is a priority to provide sustainable solutions that ensure the passengers, drivers and staff can travel in comfort, while the operators benefit from a turnkey approach, tailored to their bus types,” said Peter Hansen. “We give the bus manufacturers and bodybuilders to choose customized options and accessories like front boxes, floor heating convectors, CO2 sensors and other elements, which are managed by one Thermo King proprietary controller.”

Offering electric solutions for refrigerated transportation and mobile HVAC is part of Thermo King’s and Trane Technologies’ overall approach to reducing carbon emissions. It aligns with the company’s bold 2030 Sustainability Commitments, including the Gigaton Challenge to reduce customer greenhouse gas emissions by 1 billion metric tons.

For more information about the Thermo King solutions, please visit

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