Enhancement of automotive exhaust heat recovery by thermoelectric devices

Journal Article · Fri Jan 01 00:00:00 EST 2010 · Energy Conversion and Management

DOI:https://doi.org/10.1243/09544070JAUTO1438· OSTI ID:985757

Ibrahim, Essam ^[1]; Szybist, James P ^[2]

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1. Alabama A&M University, Normal
2. ORNL

In an effort to improve automobile fuel economy, an experimental study is undertaken to explore practical aspects of implementing thermoelectric devices for exhaust gas energy recovery. A highly instrumented apparatus consisting of a hot (exhaust gas) and a cold (coolant liquid) side rectangular ducts enclosing the thermoelectric elements has been built. Measurements of thermoelectric voltage output and flow and surface temperatures were acquired and analyzed to investigate the power generation and heat transfer properties of the apparatus. Effects of inserting aluminum wool packing material inside the hot side duct on augmentation of heat transfer from the gas stream to duct walls were studied. Data were collected for both the unpacked and packed cases to allow for detection of packing influence on flow and surface temperatures. Effects of gas and coolant inlet temperatures as well as gas flow rate on the thermoelectric power output were examined. The results indicate that thermoelectric power production is increased at higher gas inlet temperature or flow rate. However, thermoelectric power generation decreases with a higher coolant temperature as a consequence of the reduced hot-cold side temperature differential. For the hot-side duct, a large temperature gradient exists between the gas and solid surface temperature due to poor heat transfer through the gaseous medium. Adding the packing material inside the exhaust duct enhanced heat transfer and hence raised hot-side duct surface temperatures and thermoelectric power compared to the unpacked duct, particularly where the gas-to-surface temperature differential is highest. Therefore it is recommended that packing of exhaust duct becomes common practice in thermoelectric waste energy harvesting applications.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuels, Engines and Emissions Research Center (FEERC); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Transportation Research Center (NTRC)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 985757
• Journal Information: Energy Conversion and Management, Vol. 224, Issue D8; ISSN 0196-8904
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
AUTOMOBILES
EXHAUST SYSTEMS
HEAT RECOVERY
HEAT RECOVERY EQUIPMENT
THERMOELECTRIC GENERATORS
DESIGN
PERFORMANCE
WASTE HEAT UTILIZATION
NESDPS Office of Nuclear Energy Space and Defense Power Systems
thermoelectric
efficiency
heat exchanger