In 2011, Fla.-based Broward County Transit took delivery of hybrid articulated buses featuring all-electric HVAC systems from SUTRAK. With this year's deliveries, the transit authority will have 174 buses equipped with ACE (air conditioning electric) roof-mounted systems. The patented Dual Loop technology provides for redundancy, as well as the ability to scale power requirements to the cooling needs of the vehicle. Once the desired temperature is achieved, one loop can shut down while the other maintains cooling to both sides of the vehicle. This saves power (parasitic load) taken from the engine and enhances fuel savings.

The ACE 238DLGS system was chosen for the new buses, which consists of two independent self-contained housings and an air-cooled generator, belt driven from the main engine. The BRT bus design required a reduced footprint housing (100 inches long) to allow for hybrid components on the roof. Each housing is completely free of external refrigerant or heater hose runs, reducing all maintenance of such items. Internally mounted compressors and the optional electric resistance heat make this design possible. The hermetic scroll compressor technology is superior to reciprocating and screw type designs and offers significantly higher efficiencies.

A power package gives AC voltage to the system and all evaporator and condenser motors utilized operate from it. This gives major components in the system a great reliability advantage over traditional 24-volt DC designs that require more routine replacement intervals. As an electric system, the option of adding shore power connection can reduce or eliminate idling whereever a connection to external power exists. The reliability and efficiency of this technology gives it a very bright future, according to the company.