Konvekta heat pump

CO2 heat pumps conditioning Berlin electric buses from Solaris

28 March 2022

Berliner Verkehrsbetriebe (BVG), ordered in 2019 new electric buses from Solaris with amongst others, the demand to use CO2 for cooling and heating. Solaris made the choice for the Konvekta CO2 heat pump which uses the Bitzer Ecoline compressors. Development of the CO2 heat pump system began in 2017, with the first series delivered to Solaris in 2019.

Bitzer Ecoline

Konvekta supplies Solaris with the UL 500 EM CO2 HP CO2 heat pump for two different bus types: the 12 metre nE12 electric bus which is equipped with just one CO2 heat pump, whilst the Solaris nE18 articulated bus benefits from two CO2 heat pumps. Solaris then installs the compressor with double decoupling to minimize vibrations in the vehicle. 

“The use of CO2 for refrigerating and heating is not all that common in bus applications”, as Bitzer states, “it often requires expensive technologies, but the refrigerant is future-proof and boasts long-term availability fulfilling the eco-friendly and sustainability criteria”. This natural refrigerant with a GWP of 1, has a negligible greenhouse effect. According to the company even when the outside temperature is 45°C, the Konvekta CO2 heat pump achieves a good COP in cooling mode. In heating operation, the CO2 heat pump delivers results down to -20°C. With an outside temperature of -10°C it should achieve a heating capacity of 19.3 kW with a COP value of 2.3.

Bitzer Group is represented across the globe through distribution companies and production facilities at 72 locations in 37 countries. In 2020, 3,800 employees generated sales of €808 million; expenditure on research and development was €45 million.