A small, light, more efficient air conditioning system that runs on battery power has been developed by Denso Corp. for hybrid bus applications. The first application for the system is the new Hino Blue Ribbon City Hybrid introduced in late June.

The new A/C system has an integrated electric compressor instead of the more commonly used engine-belt driven compressor, allowing it to run off the diesel-electric hybrid system’s batteries even when the engine is stopped.  It also allows the A/C compressor to be placed away from the engine, shortening plumbing connections for roof-top mounted cooling systems and reducing overall weight.

Denso says the new electric compressor is 50% more efficient than previous systems and also improves operating efficiency.

“With the electrically controlled compressor and the smaller system size, the power consumption of the compressor is reduced by about 50 percent compared to DENSO’s previous systems,” said Akio Shikamura, senior managing director for Denso’s Thermal Systems Business Group.  “Moreover, the new air-conditioning system, which can operate while the engine is stopped, will contribute to the widespread use of start and stop systems.”