Powerdriver
An innovative electricity generation system for automotive and marine, powered by exhaust waste thermal energy to reduce fuel consumption
Overview
The Powerdriver project aimed to develop an innovative, environmentally friendly thermoelectric power generation system for automotive and marine applications that is powered by exhaust waste thermal energy to reduce fuel consumption.
The project further aimed to advance thermoelectric chemistry and structural understanding by creating highly innovative nano-structured, functionally graded and multi-layer TEG structured compounds targeting commercial competitiveness in waste heat energy recovery applications. The waste heat being used to produce electricity to power on-board applications in automotive and marine sectors.
Project end date
Finished – January 2014
Aims
- Overcome the limitations relating to the production of an automotive and marine power generation system by integrating cutting-edge nano-structured silicide and functionally graded telluride thermo-electric materials into a heat exchanger assembly that will enable electrical power to be generated from the exhaust system without affecting back-pressure or engine balance.
- Improve fuel efficiency for automotive and marine applications.
- Reduce emissions (CO2, nitrogen oxides, hydrocarbons, carbon monoxide and particulates).
Partners
Results
- Silicide thermoelectric materials development produced p- and n-type materials via mechanical alloying, however, they demonstrated significant handling and processing difficulties. An alternate method produced an n-type material with a ZTmax of up to 1.4. Telluride thermoelectric materials development generated p-type GeTe with a ZTmax of 1.7 and two n-type compositions based on PbI2 doped PbTe with ZTmax values of 0.9 & 1.2.
- Two small device prototype thermoelectric modules were produced; one silicide based and the other lead telluride based. A third module based on bismuth telluride was also evaluated. Separate joining methods were developed for each module based on their calculated working temperatures.
- A hot side air exhaust heat exchanger was designed and optimised so that the heat transfer was maximised without causing excessive exhaust back pressure, in order that the net fuel economy was positive. The predicted pressure drop was 21 mbar compared with 85 - 86 mbar for the final prototype and the predicted efficiency was 60% compared to the test efficiency of 48 – 50%. Complimentary cold side cooling plates were designed, built and tested. At a flow rate of 10 l/min the predicted pressure drop was 115 mbar compared with 140 mbar for the actual full prototype.
- The associated thermoelectric generator was built using solely commercially sourced bismuth telluride thermoelectric modules rather than the silicide/telluride hybrid originally designed because of joining problems experienced in the assembly of the silicide modules. An integrated automotive system based on parallel plate design was mounted onto a fully instrumented hot air test-rig to simulate the exhaust of a 2 litre gasoline car.
- For the Rolls-Royce and Halyard marine application a multi-layer parallel plate design concept based on the passenger car application was used. For the Rolls–Royce application the predicted power output was 14.0 - 27.7 kW (silicide only) and 14.6 – 31.5 kW (hybrid). For the Halyard application the corresponding figures were 2.7 – 4.9 kW and 2.9 – 5.7 kW.
- A single patent application has resulted in relation to an approach to overcome the stress related issues and to provide potential for simplifying the number of components.
