Smart multi-functional thermal systems debut at Busworld as Grayson focus on innovation for competitive edge

This content, authored by Grayson Thermal Systems, belongs to the series Busworld Spotlight, offering a dedicated space to companies presenting their vision, products, strategies and innovative solutions in the run-up to Busworld Europe 2025, from October 4–9 in Brussels, Belgium – and beyond.
Grayson is exhibiting in in Hall 5, Stand 532

At this year’s Busworld Europe, Grayson Thermal Systems made a powerful statement about the future of bus and coach technology. The Birmingham-based engineering specialist unveiled its most advanced addition to its portfolio to date – the Complete Thermal Management System (CTMS) range. The launch marks a new era in intelligent, multi-functional thermal control for electrified public transport.

Grayson smarter systems for next-generation buses

Headlining the launch was the CTMS RM-series, a roof-mounted, reversible heat-pump system that brings together passenger and driver climate control, battery thermal management, and power-electronics cooling in one fully integrated module. Designed for the next generation of electric city buses and coaches, the RM-series delivers up to 40kW of cooling at 40 °C ambient, with high-voltage capability up to 900 V DC and multiple fan configurations to suit vehicle lengths from 8 to 24 metres.

Its reversible heat-pump architecture provides efficient heating and cooling through both active and passive battery management, waste-heat recovery, and optional electrical PTC heating for extreme low-ambient conditions. The system can also integrate floor-heating and fresh-air intake functions, improving passenger comfort while reducing total vehicle energy consumption.

At the heart of the system lies Grayson’s proprietary automatic thermal-control platform, developed entirely in-house. Intelligent software dynamically manages multiple coolant loops and regulates set-points to maintain optimal thermal balance across the entire vehicle. CAN-based communication enables seamless integration with pumps, sensors, and auxiliary heaters, while optional LIN connectivity extends compatibility across global OEM platforms.

Grayson RM-series, designed for simplicity, built for scale

With its modular rooftop packaging and configurable architecture, the RM-series simplifies installation and vehicle integration, giving OEMs a scalable, high-performance platform engineered to meet the challenges of electrification, range, and passenger comfort.

“Our RM-series represents a real leap forward in bus thermal management,” explained Stuart Hateley, Managing Director at Grayson Thermal Systems.

“It brings together everything we’ve learned from decades of designing, manufacturing, and servicing heating and cooling systems for the world’s leading bus brands.

“For OEMs, it delivers modularity, efficiency, and the intelligent control that modern electric platforms demand. For operators, it means improved serviceability and long-term reliability, essential factors when vehicles are expected to perform faultlessly in daily service.”

Expanding the CTMS family

Alongside the RM-series, Grayson also introduced the CTMS CM-series, a compact, chassis-mounted, reversible heat-pump system developed for electric on-highway commercial and off-highway special-purpose vehicles. Like its rooftop counterpart, the CM-series integrates battery, power-electronics, and driver-cabin thermal management within one intelligently controlled unit, offering up to 10 kW of cooling at 40 °C ambient.

“The CM-series extends our CTMS technology into sectors where packaging space is tight but performance expectations are just as high,” continued Hateley.

“Together, the RM- and CM-series give OEMs a consistent technology base across vehicle platforms, simplifying design and validation while maintaining exceptional efficiency.”

Engineering innovation and British manufacturing excellence

Grayson’s Busworld showcase underlined the company’s commitment to combining British engineering ingenuity with a strong manufacturing capability. Every CTMS module is designed, validated, and built in the UK using vertically integrated processes, from component machining and fabrication through to assembly, testing, and quality assurance.

“This launch is much more than new product lines,” said Hateley. “It’s a reflection of our strategy to compete through innovation and quality. By investing in advanced design and manufacturing technologies, we’re giving our customers — the world’s leading bus and coach OEMs — the competitive edge they need.

“Our systems are conceived and produced by engineers who understand vehicles from the inside out. That allows us to innovate quickly, control quality at every stage, and ensure our solutions deliver measurable benefits for better efficiency, lower energy use, and greater comfort for passengers and drivers alike.”

A total thermal-management partner

Complementing the CTMS range, Grayson also revealed several new high-voltage components, including its EW3 and EW4 PTC electric water heaters for 800V DC platforms and the PE1-800V DC cooler for power-electronics and traction-motor applications. Together, these products reinforce Grayson’s position as a total thermal-management supplier capable of delivering both complete systems and individual subsystems to suit OEM integration strategies.

“The addition of our new high-voltage heaters, coolers, and pumps shows that we’re not only designing complete thermal systems but also the individual components that make those systems work,” added Hateley.

“It means our customers can specify a single integrated CTMS or combine our sub-systems to create their own bespoke architecture, all with the assurance of proven compatibility and quality.”

Building on heritage, engineering the future

Founded more than 45 years ago, Grayson Thermal Systems has evolved from a family-run radiator repair shop into a global engineering group supplying advanced thermal-management solutions across Europe and North America. Yet its roots in the bus and coach sector remain central to its identity.

“Buses and coaches have always been the heart of our business,” concluded Hateley.

“Our experience supporting operators and OEMs through multiple technology shifts, from diesel to hybrid and now fully electric, gives us a deep understanding of what matters: reliability, efficiency, and serviceability.

“By combining that heritage with continual investment in R&D and manufacturing, we’re ensuring Grayson remains at the forefront of thermal innovation for decades to come. The CTMS range is proof of that commitment, a new generation of intelligent, high-performance systems engineered to keep people and vehicles moving.”