Identifying Cost Effective Routes To Optimised Energy Recovery For The Fuel Economy Of Vehicles

The internal combustion engine which is in everyday use in a wide variety of applications remains one of the most cost effective means of generating power. A typical engine however loses substantial amounts of energy in its normal operation and there is clear potential to utilise this energy. The largest flow is in the exhaust system of the vehicle, and it is here that the proposed research is focussed.
The main objective of the project is the realisation of an efficient method of energy recovery using a thermoelectric generator and utilising a new type of material known as a skutterudite. By adopting the same internal structure, skutterudites simulate a naturally occurring mineral which has the vital properties of low thermal conductivity with low electrical resistance. The principal advantage of these materials is their potential for cost reduction by utilising low cost metals in their structure. A second and important advantage is the future potential for novel manufacturing techniques in which the active elements of the thermoelectric generator are made using additive methods to build up the kind of complex shapes that are required.
The project brings together three universities that can cover the range of capabilities from the chemistry of materials through to systems integration methods.
The Heriot-Watt team will synthesise new materials using progressively lower cost materials to demonstrate that the required thermoelectric performance can be obtained using low cost materials. The Cardiff team will integrate modules, incorporating protective coatings to ensure the durability of the generator. At Loughborough, the scope to integrate thermo-electric (TE) generators with other functions such as after-treatment will be explored. The Loughborough team will work with the Cardiff team to identify novel methods of integrating the TE modules into a heat exchange device, regarding the requirements imposed by different types of engine.
The project concludes with the practical demonstration of TE generators and a portfolio of simulation results that demonstrate how the cost path and the path to levels of commercial performance will be realised.

The aim of the project is the confirmation of a set of technologies as being the firm basis for energy recovery techniques. Energy recovery contributes to the fuel efficiency of vehicle propulsion and power generation, and will contribute to carbon dioxide (CO2) emissions targets. The primary impact is in the availability of the technologies to potential users. Those users for the most part will be suppliers to the automotive, marine and industrial machinery sectors. For the manufacturers of machinery and engines, the immediate impact of the research will be an understanding of the scope and cost of energy recovery equipment. For their suppliers, the technology, its manufacturing implications, and cost of production will be understood.
For legislators and policy makers the availability of information about a cost effective route to energy efficiency is a major contribution to their assessment of feasible policy routes to lower energy usage.
The proposed path for materials development has the potential to initiate a wholly new supply chain. Skutterudite materials are not currently manufactured in bulk and their incorporation into TE modules is simply done in the lab. While a large company like JM will be in a strong position to develop the manufacture of skutterudites, because of their existing process expertise, module manufacture may well develop in SMEs and start-up companies. ETL is an example of an SME which has a niche interest in cooling that has begun to grow a business in TE module production for energy harvesting from waste heat.
There is a strong process aspect to the proposal and the successful demonstration of component in the loop techniques will allow their dissemination to the wider community. The modelling methods and test architecture will be made available through an open source arrangement as the first step to building an academic community to refine and develop these techniques. Modelling and optimisation methods are particularly important in this application. A wider dissemination of methods will enhance research efficiency while academic groups can continue to explore in confidence their own component and system technologies
For those with a broad interest in the feasibility of TE methods, we are proposing also to offer an open source application toolkit that will allow the investigation of operating conditions, material choices, and system configuration in relation to fuel economy gains. We believe that this kind of access will broaden interest and permit rational judgements to be made by potential users.
The proposal to explore the exhaust system as a single concept complete with its own operating environment (pressure and temperature) where key functions (energy recovery and after-treatment typically) are integrated is novel. This objective has the potential to open up new research agendas for academic colleagues in after-treatment, heat transfer and the application of turbocharging methods.
Outside of the ground vehicle sector, there is the potential for applications in the Aero sector in both power generation and temperature management of key components. The investigators have already had some discussions in this area with an Aero engine company. This initial interest sets the agenda for a wider discussion in other sectors. The involvement of Caterpillar with their large portfolio of products represents a strong potential.