Decarbonating Transport for London’s Croydon Tram Depot with IR

As part of its wider carbon-reduction strategy and the Mayor of London’s ambition for a net-zero London by 2030, Transport for London (TfL) is undertaking a major programme to decarbonise heating and improve energy efficiency across its operational estate.

One of the sites focused on within this programme was the Therapia Lane tram depot in Croydon; a large, industrial, 24/7 operational facility which was previously heated by an ageing and inefficient gas boiler system.

The tram depot is a huge space, with multiple operational activities and loading bays/work spaces with varying heating requirements, and so needed a highly controllable electric heating system that provided the required comfort levels for the multiple different operational areas. The tram shed building opens its doors regularly to let trams in for maintenance, and the previous convection-based system proved to be inefficient, as the hot air would easily escape when the shed doors were open.

Mick Baines, Managing Director of InterLED, part of Herschel Group, worked with TfL and the Vital Energi project team over a 12 month period. The first 6 months of which involved carrying out extensive modelling of optimal heater positioning, zone controllability, and required human comfort levels across the depot’s diverse workspaces, which included maintenance bays, pits, workshops, and continuously operating loading areas.

To meet the requirements, a total of 60 infrared heaters were installed; 43 high performance, UK-manufactured longwave Herschel Advantage heaters were chosen along with 17 low glare, shortwave Herschel Vulcan heaters.

“We found Herschel and InterLED, who had the provision of these assets…. which aren’t affected by the air. So it was a bit of a no brainer really, for us, and a massive success to get them to where they are now. Already, our staff wellbeing is incredibly high and people are very, very happy with them.

Within this depot, it’s 24/7. We only shut on Christmas Day. So getting this kit in into the right place in the least disruptive way as possible is an absolute requirement for us at TfL, and I’m happy to say that we’ve delivered that here”. – James Merci, Project Manager, TfL

This choice of different heater types ensured that all areas requiring instant, on-demand heating were effectively heated as required, whilst other heaters were specified to contribute to the overall ambient temperature on a timed/temperature setting. This allowed comfort and efficiency to be optimised based on workflow patterns and controllability demands.

“We needed to find a solution that heated people rather than spaces. And the IR heaters that were proposed by our engineers originally was deemed to be the most sensible option…and that’s proved the case.

We’ve engaged with InterLED and you’ve taken that concept and delivered this which has proved to be fantastic. All the feedback has been remarkable really, and the install is really neat/tidy. The team have been really professional”. – James Asterley, Vital Energi Ops Manager

All of the installed heaters are operated through a UK-manufactured Herschel control system which allows for:

• Zonal heating control
• Timed scheduling
• Energy monitoring for ongoing carbon-reduction tracking
• Fault-finding and diagnostics

By heating only occupied zones, the system significantly reduces energy use and carbon emissions compared to heating the entire air volume which is a major advantage in large, draught-prone depots.

The heaters radiate heat outwards and downwards, ensuring that operatives remain comfortable within the effective radiant area, even when ambient air temperatures fall below minimum workplace thresholds due, for example, to open depot doors. The InterLED project team was able to use Thermal Comfort Index modelling to demonstrate this.

Large operational buildings such as transport depots have always been considered ‘hard to heat’ due to high ceilings, open bays, constant vehicle movement and frequent draughts.

As infrared heats people and surfaces directly and is not reliant on heating air, it is a much more effective heating system for hard to heat spaces with large open doors. The project demonstrates what is possible in replacing outdated fossil-fuel systems with environmentally friendly, cleaner technologies in large, hard to heat spaces.

Mick Baines, MD InterLED comments:

“From the outset, this project was recognised as a challenging environment for electric heating. We were fully confident however that, with the right approach, it could be successfully delivered through infrared. Vital’s technical team took on board all our guidance, working carefully within the parameters set by TfL, to develop an effective and robust design.

Clear, evidence backed discussions around thermal comfort, supported by heat mapping, provided full assurance on achievable ambient temperatures relative to external conditions.

The resulting system, with flexible, easy to use control, enables staff to maintain consistently high levels of comfort. We are thrilled that the success of this project has led to further projects within the TfL estate”.

Paul Morey, CEO Herschel Infrared, outlines:

“This was our first large-scale commercial installation since InterLED became part of the Herschel Infrared Group. Our ability to now offer the full heating system service from design and manufacture to installation has proved to be a great success on this project. TfL have extremely high standards, and the results are fantastic evidence of what we are able to deliver for similar organisations seeking to decarbonise their heating”.

Contact the Herschel Team today for a consultation and experience the future of heating for yourself