Waste Heat Recovery
[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Fraunhofer characterizes Alphabet Energy thermoelectric PowerCard; up to 5% fuel economy improvement in automotive
January 14, 2016
Alphabet Energy is commercializing low-cost, efficient thermoelectric materials for power generation leveraging technology initially developed at the Lawrence Berkeley National Laboratory. (Earlier post.)
The company has now announced characterization from the Fraunhofer Institute for Physical Measurement Techniques IPM of heat flow and thermal resistance (in air) of the Alphabet Energy PowerCard, the company’s core thermoelectric device for power generation. The PowerCard has shipped to customers in a variety of industries, including automotive; has been tested extensively; and is now entering high-volume production.
Manchester team greatly broadens thermal window of thermoelectric material using graphene; potential vehicle applications for waste heat recovery
July 22, 2015
Researchers at the University of Manchester (UK) have shown that the thermal operating window of the thermoelectric material lanthanum strontium titanium oxide (LSTO) can be expanded down to room temperature by addition of a small amount of graphene. Applications of LSTO-based thermoelectric materials are currently limited by their high operating temperatures of >700 °C.
Rather than working within the usual narrow “thermal window”, these bulk graphene/LSTO nanocomposites exhibit useful ZT values across a broad temperature range of several hundred degrees, the team reported in the journal ACS Applied Materials & Interfaces. This increase in operating performance can enable future applications such as thermoelectric generators in vehicles for waste heat recovery and other sectors, the researchers suggested.
Alphabet Energy introduces PowerModules for modular thermoelectric waste heat recovery; partnership with Borla for heavy-duty trucks
June 24, 2015
Alphabet Energy, founded in 2009 at Lawrence Berkeley National Laboratory, announced the availability of its thermoelectric generator PowerModule as a standalone product, available to meet the specific application needs of a range of industries, including transportation. The company also announced it will partner with Borla jointly to develop and to commercialize a next-generation-exhaust system incorporating PowerModules, with the goal of delivering significant fuel savings for commercial fleet truck fleets.
The Alphabet Energy PowerModule is a solid-state, liquid-cooled electrical generator that converts exhaust heat into electricity using Alphabet Energy’s proprietary PowerBlocks thermoelectric materials.
Free piston/ORC system for automotive waste heat recovery being tested at University of Brighton
June 18, 2015
A prototype automotive waste heat recovery system has been fired up on a recently commissioned test rig at the University of Brighton. The organic Rankine cycle test rig uses a novel linear free piston expander from Libertine (earlier post) to overcome the technical and economic barriers to using Rankine cycle technology for automotive waste heat recovery.
Initially configured to simulate heavy duty truck applications, the 20 kWe system can be scaled down to 3 kWe for light duty trucks and passenger cars. Libertine expects the results from rig tests to confirm the system’s potential to convert the high grade heat in the exhaust into electrical power, which can contribute to either powertrain or auxiliary loads.
Evident Thermoelectrics acquires GMZ Energy
May 19, 2015
In a major expansion move, Evident Thermoelectrics has purchased the assets of GMZ Energy, Inc. a developer of high temperature thermoelectric generation (TEG) systems, in an acquisition that includes all patents, equipment, product lines, website, customer contacts and brand. In December 2014, GMZ had successfully demonstrated a 1kW TEG designed for diesel engine exhaust heat recapture in a Bradley Fighting Vehicle (earlier post).
The purchase comes shortly after Evident’s April announcement of a licensing agreement with NASA and is intended to solidify the company’s position as a leader in high temperature thermoelectric applications. (Earlier post.)
MIT team finds chemical functionalization can lead to efficient graphene-based thermoelectric materials
April 14, 2015
Researchers at MIT are predicting that predict that suitable chemical functionalization of graphene can result in a large enhancement in the Seebeck coefficient for thermoelectric materials, leading to an increase in the room-temperature power factor of a factor of 2 compared to pristine graphene, despite degraded electrical conductivity.
Furthermore, the presence of patterns on graphene reduces the thermal conductivity, which when taken together leads to an increase in the figure of merit for functionalized graphene by up to 2 orders of magnitude over that of pristine graphene, reaching its maximum ZT ∼ 3 at room temperature according to their calculations, as reported in a paper in the ACS journal Nano Letters. These results suggest that appropriate chemical functionalization could lead to efficient graphene-based thermoelectric materials.
Renault Trucks Optifuel Lab 2 vehicle results: reduction in fuel consumption by 22% compared to conventional truck
March 19, 2015
Following several months of road trials and test bench programs adding up to the equivalent of 20,000 km (12,427 miles), Renault Trucks Optifuel Lab 2 laboratory vehicle (earlier post) is recording fuel consumption 22% lower than that of a production Renault Trucks T. This means 7.2 liters of diesel are saved for every 100 km covered, together with a 194 g reduction of CO2 emissions for every kilometre travelled.
Optifuel Lab 2 has been equipped with 20 technologies, each of which meet four major challenges associated with consumption: energy management, aerodynamics, rolling resistance and driving aids. Based on a Renault Trucks T, Optifuel Lab 2 is an ongoing version of the Optifuel Lab 1 introduced in 2009.
SUTD team proposes low-temperature thermionic converter with graphene cathode; about 45% efficiency
March 09, 2015
Researchers at the Singapore University of Technology and Design (SUTD) are proposing that it is possible to design an efficient graphene-cathode-based thermionic energy converter (TIC)—a device for converting heat to electricity leveraging the phenomenon of thermionic emission, or the release of electrons from a hot body—operating at around 900 K (626 °C) or lower, as compared with a conventional metal-based cathode TIC operating at about 1500 K (1227 °C).
With a graphene-based cathode at 900 K and a metallic anode, the efficiency of the proposed TIC would be about 45%, they concluded in a paper on the work published in the journal Physical Review Applied. If realized, an efficient, low-temperature TIC could provide a supplementary or an alternative approach to thermoelectric devices for waste heat recovery using low grade waste heat—i.e, from engine exhaust or industrial processes.