High-Voltage Electric Rooftop Air Conditioning for Large Commercial Vehicles

The Cool Top 120 e is a lightweight, high-performance rooftop air conditioning system designed specifically for the thermal management requirements of large electric passenger transport and logistics vehicles. By utilizing an integrated high-voltage electric compressor, the system operates independently of the vehicle's propulsion motor, facilitating consistent climate control in city buses and heavy-duty commercial applications.

Technical Integration and Performance Specifications
The system delivers a cooling capacity of 12 kilowatts and a heating capacity of 10 kilowatts, provided through an integrated high-voltage heater. To maintain efficiency within an automotive data ecosystem focused on energy preservation, the unit operates on a voltage range from 400 to 800 volts. This wide operating range allows the system to interface directly with the traction batteries of most modern electric bus platforms without requiring additional transformers.

Weight reduction serves as a primary technical objective for electric vehicle components to maximize driving range. The Cool Top 120 e weighs 160 kilograms, a metric achieved through the use of lightweight housing materials and a compact internal layout. The unit measures 2,330 x 1,510 x 262 millimeters, providing a low-profile aerodynamic cross-section that reduces drag during transit.

Installation and Communication Standards
To ensure compatibility with global manufacturing standards, the system utilizes the CAN (Controller Area Network) bus protocol for communication with the vehicle’s central control unit. This integration allows for precise monitoring of energy consumption and real-time adjustment of cooling cycles based on passenger load or ambient temperature sensors.

Webasto designed the unit for ease of installation by consolidating all essential components—including the electric compressor, evaporator, and condenser—into a single "plug-and-play" rooftop module. This design reduces the complexity of the digital supply chain for vehicle OEMs (Original Equipment Manufacturers) by minimizing the number of individual parts and refrigerant lines required during vehicle assembly.

Operational Reliability in Diverse Climates
The system is engineered to function in ambient temperatures up to 45 degrees Celsius. It employs an automated de-icing function and a soft-start feature to prevent current spikes that could stress the vehicle's electrical grid. For heating, the unit utilizes a high-voltage PTC (Positive Temperature Coefficient) heater, which provides immediate thermal output even in sub-zero conditions, ensuring passenger comfort without relying on waste heat from a combustion engine.

The Cool Top 120 e was showcased at Busworld Europe, which took place from October 7 to 12, 2023, in Brussels, Belgium. The technology demonstrated how modular climate systems can be adapted to support the transition from internal combustion engines to fully electric powertrains in the public transport sector.

www.webasto.com