Air conditioning (A/C) manufacturers report noticing an overall need for more energy-efficient and weather-resistant products, in addition to systems that allow for more bus design flexibility. As a result, rooftop systems, corrosion-resistant skirt condensers and eco-friendly options are among some of the latest air conditioning trends in transportation.
As the industry continues to grow, so does a transit agency’s ability to find a more fitting solution for their vehicles. Keep your operation at the forefront by integrating products that address new technologies, customer needs and emerging environmental standards.
American Cooling Technology
The application of rooftop A/C systems has been an industry-wide trend within the past few years. While the best option for a transit agency varies from vehicle to vehicle, there are several benefits from having an A/C installment that isn’t underneath a bus.
Condenser coils located on the roof of a vehicle access cleaner air compared to coils under a bus. The air circulated is also cooler, — because the system is physically distanced from engine and road heat — which increases overall capacity. Ground debris is also bypassed during transit, reducing inevitable maintenance costs.
Having an A/C option atop a bus gives bus manufacturers more flexibility with design as well. Even a split system, in which the condenser is roof mounted, but the evaporator remains ceiling mounted or in-wall, would allot companies more versatile use of space. More room is created for applications like wheelchair lifts and luggage compartments, which traditionally utilize space under a vehicle.
To satisfy the growing demand for skirt system alternatives, American Cooling Technology (ACT) recently introduced a line of roof-mounted condensers: CR-2, -3 and -4.
The CR-2, a two-fan condenser, has been available since 2011, and CR-4 was released last fall. However, the York, Pa.-based ACT wanted to offer a complete line, so in January, it went into production for the CR-3. In the past, ACT commonly placed two CR-2 condensers into medium size buses too large for one CR-2 and too small for a CR-4. The option to have a CR-3 application now reduces the installment complexity through fewer refrigerant connections.
“Having these different capacities available now gives us flexibility for customer requirements — they don’t have to oversize or undersize anymore,” says ACT GM Dave Oberdorff. “This fits a market niche for capacity and application in fitting the product to the bus.”
The CR-3 rooftop condenser features three high-capacity 12-inch fans, a lightweight aluminum frame, a TPO cover and O-ring connections for maximum leak protection. There are also heat rejection coils and an enhanced copper tube with aluminum coils. The CR-3 system is a single-circuit design, and the CR-4 is available in both single- and dual-circuit designs.
The line of CR Rooftop condensers currently use a split system design, but ACT has partnered with E-Climate to make a complete rooftop set available to customers.
There are also recent industry trends toward intelligent A/C controls that can operate through the bus multiplexing system, according to Oberdorff. Now becoming more of an industry standard, these controls usually increase the total cost of the A/C system, but offer operational savings over the life of the vehicle.
“We’re seeing more state and agency requests for this kind of capability overtime,” says Oberdorff. “They’re looking at it as something that’ll help with operations’ budgets down the road.”
Another trend to look out for, says Oberdorff, is the shift away from copper brush motors to brushless motors. Although more costly upfront, they require less maintenance, offer more control options and are more efficient.
“You can get as much as four to five times the life out of the brushless motors,” says Oberdorff. “And, they’re becoming more cost competitive.”