From now on, all air-conditioned hybrid buses for the European market will be equipped with the REVO-E all-electric roof-mounted air-conditioning system.
In 2009, Volvo Bus Corporation entrusted Spheros with the supply of air conditioning for the Euro 5 hybrid vehicles. Now, Spheros has also been contracted to equip the new Euro 6 city and intercity buses. The straight and articulated versions of the single-deck, low-floor Volvo 7900 Hybrid Euro 6 buses feature the REVO-E. The 8900-series intercity buses feature the REVO Classic. The heating and ventilation units are also made by Spheros.
The figures for the new Volvo Euro 6 hybrid buses are impressive: 
is 37 percent lower, and emissions are 40 to 50 percent lower. The optimization of the air-conditioning system plays a key role here. “For us, this project is a decisive step forward towards electric mobility. We are proud to have forged this path with Volvo”, says Markus Hummel, Spheros Key Account Manager.
Demand-based control
The REVO-E fully electric air-conditioner is suitable for hybrid, electric, and trolley buses. The main benefits of this efficient system are the control capabilities, the intelligent incorporation of electrical components, and the compact size. The refrigerant compressor is integrated in the compact roof unit via a patented vibration isolation unit. It is electrically powered, which guarantees uninterrupted, high cooling performance even when the combustion engine is temporarily turned off by the hybrid technology.
The drive system, which runs independent of the combustion engine, is used to increase the overall efficiency of the REVO-E through a demand-based control of electrical components. This allows the compressor speed to be adapted to the environmental conditions. The evaporator fans automatically adjust themselves based on the required airflow, and the condensation fans are continuously kept at an optimal setting.
The units are manufactured at the Spheros factory in Neubrandenburg and delivered to the Volvo factory in Wroclaw, Poland. In addition, the REVO-E is also used worldwide by the Volvo partners who build buses based on the Volvo Euro 6 chassis.
The air-conditioned hybrid buses have been very well received by the market, as can be seen from the order numbers so far. It is planned that around 400 to 500 REVO-E units will be delivered to Volvo annually. The first buses have already been delivered to operators in Hamburg (Germany), as well as Madrid (Spain), Drammen (Norway) and Lothian (Scotland).
