The roof-mounted air conditioning system is additionally used as a heat pump during the colder season of year and therefore ensures an effective and efficient climate control of the passenger compartment. Further advantages are offered by the use of the CO2 refrigerant. It is convincing with a particularly efficient use of the heat pump even at very low temperatures of up to minus ten degrees Celsius.
A further plus: even during the charging of the batteries in the depot the vehicle interior can be pre and even over-conditioned to the desired temperature. This allows the bus to already start heated or cooled depending on the time of year. The layout of heating and climate control is orientated by the requirements of the Association of German Transport Companies (VDV). At extreme ambient temperatures, the comfort level in the limit areas is slightly lowered in the interests of energy consumption and therefore range. Instead of a constant inside temperature setting all year round, this orientates itself to the situation-adapted comfort feeling of the passengers. As the passengers generally only spend a short amount of time in the vehicle and their clothing is generally adapted to the time of year, a higher inside temperature setting is used on hot summer days and a lower one on cold winter days, without leaving the area of comfort.