Modelling and development of efficient ventilation strategies to ensure bus passengers’ thermal comfort whilst minimising energy consumption.

Abstract

In recent years the UK medium- to heavy-duty bus market has seen a shift away from manufacturing diesel buses, to making diesel-hybrid buses, and now to focusing on the production of battery electric buses (BEB’s) and fuel cell electric vehicles (FCEV). This change has challenges, one of which is how to ensure passenger comfort. Providing treated air to the passenger cabin can require large amounts of energy to be drawn from the battery which can have a significant impact on the range of a vehicle.

This research provides an analysis method which can be used by industrial and academic researchers looking to utilize advanced methods of assessing thermal comfort and an understanding of thermal comfort principles to inform decisions that can minimize vehicle energy consumption.

The analysis method features 6 steps: define a case for investigation, develop a ventilation strategy for providing treated air to the bus cabin, assess the energy required to provide the treated air to the cabin, calculate the local heat transfer occurring between a person and their environment, assess the level of thermal sensation and comfort for a person in that environment, and use a holistic review of all results to recommend alternative ventilation strategies with the goal of minimising energy consumption while ensuring thermal comfort. A number of lumped-parameter models as well as 3D CFD methods are described to help achieve this.

To demonstrate use of the analysis method two ventilation strategies are defined: a baseline, and an alternative case where changes are made based on the results and recommendations from the first case. The analyses utilise a localised approach to assess the sensation and comfort levels across the body, and the changes which are implemented between Case 1 and Case 2 result in a reduction in the HVAC energy consumption by up to 8% over the period of analysis.

Thesis is embargoed until 31 December 2029.

Date of Award	Dec 2024
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Northern Ireland Department for the Economy & Wrightbus Ltd
Supervisor	Marco Geron (Supervisor), Eoin Cunningham (Supervisor), Roy Douglas (Supervisor) & Declan Nolan (Supervisor)