Air Handling System Optimisation for Fuel Cell Applications

Hydrogen fuel cells are a vehicle power source with several advantages compared to the fossil-fuelled incumbents. Fuel cells emit no harmful emissions, producing only electricity and water from hydrogen fuel and oxygen from the air. The electricity generated is used to power electric motors, similar to battery electric vehicles (BEVs), but the use of a consumable fuel instead of batteries alone negates the need for time-costly recharging. Hydrogen fuel can also be produced in a 'green' manner, such as by solar-powered electrolysis, which is more environmentally sustainable than fossil fuel use. This combination of benefits make hydrogen fuel cells a pivotal technology for the reduction of carbon emissions in the transport sector.

To feed the chemical reaction in the cell, oxygen is provided to the cathode from the ambient air, but must be compressed and managed in various ways to maximise performance and efficiency. Components added to the system which handle inlet air and improve fuel cell efficiency also induce parasitic losses, reducing overall system efficiency by consuming electrical energy. Air handling consumes 5% of the power provided by the stack in some examples, but could be much more, so is a key area for development to understand and improve system efficiency. There are existing methods to offset parasitic losses, such as using turbines to recover energy from the exhaust flow, as is common in turbocharged diesel engines. This appears to be less lucrative for fuel cells, as the exhaust flow is different in nature. For example, it is comparatively low temperature and is more humid, so contains less energy, and is non-pulsating, presenting different requirements and considerations. These gains and losses from air handling components must be assessed at a system level to ensure optimal air management for fuel cells. There are also further restrictions to consider regarding the practicality of air management solutions, such as avoiding contact of the exhaust water with electrical components.

The aim of this PhD project is to optimise air handling systems for hydrogen fuel cells, particularly for heavy duty applications. Fuel cells are more suited to heavy duty applications than light duty due to the low volumetric density (energy per unit volume) of hydrogen. Heavy duty vehicles tend to have sufficient available space that is needed to store enough hydrogen for an appropriate range.

The expected project methodology is as follows:
1. Conduct research on the interaction between the air path and the fuel cell to understand the requirements and constraints of the fuel cell's air supply. This will help appreciate the role of air handling components later in the project. It is predicted this stage will consist of a literature review and numerical testing in GT Suite to supplement findings from secondary sources.
2. Match the air flow requirements to existing air management solutions. This will consist of further literature review to comprehensively assess a breadth of options, noting the roles, effects, pros, and cons of different components and configurations.
3. Devise an improvement to modelling techniques for fuel cell air management. This might be a humidity model which better represents real life conditions and provides data which is closer to that of physical experiments, for example.
4. Use knowledge gained to propose novel air handling systems and carry out system optimisation. This will provide an understanding of the pros and cons of different configurations and subsequently determine the best applications for each.

Impact Summary

This proposal has been developed from the ground up to guarantee the highest level of impact. The two principal routes towards impact are via the graduates that we train and by the embedding of the research that is undertaken into commercial activity. The impact will have a significant commercial value through addressing skills requirements and providing technical solutions for the automotive industry - a key sector for the UK economy.

The graduates that emerge from our CDT (at least 84 people) will be transformative in two distinct ways. The first is a technical route and the second is cultural.

In a technical role, their deep subject matter expertise across all of the key topics needed as the industry transitions to a more sustainable future. This expertise is made much more accessible and applicable by their broad understanding of the engineering and commercial context in which they work. They will have all of the right competencies to ensure that they can achieve a very significant contribution to technologies and processes within the sector from the start of their careers, an impact that will grow over time. Importantly, this CDT is producing graduates in a highly skilled sector of the economy, leading to jobs that are £50,000 more productive per employee than average (i.e. more GVA). These graduates are in demand, as there are a lack of highly skilled engineers to undertake specialist automotive propulsion research and fill the estimated 5,000 job vacancies in the UK due to these skills shortages. Ultimately, the CDT will create a highly specialised and productive talent pipeline for the UK economy.

The route to impact through cultural change is perhaps of even more significance in the long term. Our cohort will be highly diverse, an outcome driven by our wide catchment in terms of academic background, giving them a 'diversity edge'. The cultural change that is enabled by this powerful cohort will have a profound impact, facilitating a move away from 'business as usual'.

The research outputs of the CDT will have impact in two important fields - the products produced and processes used within the indsutry. The academic team leading and operating this CDT have a long track record of generating impact through the application of their research outputs to industrially relevant problems. This understanding is embodied in the design of our CDT and has already begun in the definition of the training programmes and research themes that will meet the future needs of our industry and international partners. Exchange of people is the surest way to achieve lasting and deep exchange of expertise and ideas. The students will undertake placements at the collaborating companies and will lead to employment of the graduates in partner companies.

The CDT is an integral part of the IAAPS initiative. The IAAPS Business Case highlights the need to develop and train suitably skilled and qualified engineers in order to achieve, over the first five years of IAAPS' operations, an additional £70 million research and innovation expenditure, creating an additional turnover of £800 million for the automotive sector, £221 million in GVA and 1,900 new highly productive jobs.

The CDT is designed to deliver transformational impact for our industrial partners and the automotive sector in general. The impact is wider than this, since the products and services that our partners produce have a fundamental part to play in the way we organise our lives in a modern society. The impact on the developing world is even more profound. The rush to mobility across the developing world, the increasing spending power of a growing global middle class, the move to more urban living and the increasingly urgent threat of climate change combine to make the impact of the work we do directly relevant to more people than ever before. This CDT can help change the world by effecting the change that needs to happen in our industry.