Cooling the Tube

Green Energy Futures supported the development and validation of a more energy-efficient cooling solution for the London Underground to replace the failing PAHU system, reducing energy use and costs by over 60%.

Project Overview

As London prepared for the introduction of new tube stock on the Piccadilly Line, Green Energy Futures supported the assessment and development of an effective cooling solution for a network where existing systems were failing to cope. The result: an innovative, energy-efficient alternative that significantly outperforms the legacy PAHU (Platform Air Handling Unit) systems.

Rising tunnel temperatures and ageing cooling infrastructure created a major operational challenge for TfL, limiting train throughput and compromising passenger comfort. The existing PAHU systems were underperforming, expensive to maintain, and not future-ready for increased service frequency.

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Green Energy Futures led a targeted assessment and solution development process that included:

  • Cooling Demand Assessment: Evaluated environmental conditions and thermal loads across five high-priority stations.
  • Technology Evaluation: Analysed the performance limitations of existing PAHU systems and identified opportunities for improved efficiency.
  • Concept Development & Proofing: Designed and supported the testing of a new cooling system tailored to harsh underground conditions.
  • Performance & Cost Analysis: Delivered projections showing dramatic reductions in energy use, maintenance requirements, and capital expenditure.

Outcomes of the trial included:

  • 65% reduction in operational energy use and maintenance costs
  • 55% lower capital cost compared to the existing system
  • Increased cooling capacity enabling higher train frequency and improved passenger experience
  • Scalable, low-maintenance solution with long-term cost savings

Project Detail

Department

Consultancy

Location

Trial at Holborn Station

Key Services

Building Energy Performance Evaluations

HVAC Optimisation & Smart Climate Control

Carbon Footprint Assessments

Energy Management & Monitoring Solutions