AC353 Inline Air-Conditioning System Enhanced for North America

Oct 6, 2008

San Diego, Calif., United States

With a global reputation for superior performance and reliability, Carrier’s AC353 inline rooftop bus air-conditioning system has been enhanced to meet the demanding and varied needs of the North America market. The AC353 system is on display at the International Public Transportation Expo 2008 in San Diego, Oct. 6-8.  Carrier Corp. is a subsidiary of United Technologies Corp. (NYSE:UTX).

The AC353 system is available in 24-kilowatt (kW) and 35 kW capacities to cover the majority of climate zones from moderate to extreme conditions, enabling customers to select the optimal capacity for their application, using the same footprint. 

“Inline rooftop air-conditioning systems are growing in popularity in North America, as recent changes in diesel engine requirements put space in the rear of the bus at a premium,” says Joseph Giacona, product manager, Carrier North America Bus. “Inline rooftop systems also are easier to install and maintain, and Carrier has a 25-year track record of success around the world with these systems.”

The powerful AC353 system offers superior performance and reliability, using Carrier’s micro-channel heat exchanger (MCHX) coil technology, which delivers significant performance improvements through better heat transfer and thermal performance. MCHX technology has been widely used in millions of automobiles since the early 1980s.

“MCHX technology has been used by Carrier in commercial building and transport refrigeration applications with substantial success,” says Giacona. “It takes advantage of established heat transfer principles through the use of multiple smaller channels in parallel to maximize the heat transfer surface contact.”

Able to better withstand dirt and road treatment agents and easier to clean thanks to its enhanced robustness, the MCHX coil increases system reliability and life by offering better corrosion resistance. In fact, Carrier’s MCHX coils exceed ASTM B 117 corrosion test minimum requirements by 50 percent. The MCHX condenser’s single-row coil design also contributes to reducing the amount of refrigerant needed to circulate through the system.

MCHX coil efficiency results in a more compact unit – 15 percent to 20 percent shorter than the previous AC353 – freeing up valuable space on the bus roof. The AC353 system also is 12 percent to 16 percent lighter than its predecessors, which translates into lower overall fuel consumption and reduced life cycle cost.

“The AC 353 system offers bus builders and operators the perfect balance between standardized design and increased flexibility,” says Mauricio Salgado, Carrier global bus product manager. “A wide range of options is available to serve our customers’ needs. They can choose the right system for the right application, with the goal of ensuring desired passenger comfort.”

Keeping the extensively tested basic design as a standard ensures reliability. The AC353 product family installs faster than previous systems thanks to its one-piece evaporator housing, and is easier to service from both inside and outside of the bus.

“Initial customer feedback has been excellent!” adds Salgado. “We fully expect the AC353 system to continue the evolution of bus air conditioning that its predecessors began two decades ago.”

About Carrier Corp.
Headquartered in Farmington, Conn., Carrier Corp. is the world’s largest provider of heating, air-conditioning and refrigeration solutions. With 2007 revenues of $14.6 billion, Carrier has approximately 43,000 employees worldwide and operations in more than 170 countries. Carrier is a part of United Technologies Corp., a Hartford, Connecticut-based provider of products and services to the aerospace and building systems industries worldwide. Visit for more information.