Heat Rejection Using Advanced Materials — Passive and Active Cooling Strategies

Principal Investigator: John Wagner, Clemson University, jwagner@clemson.edu
Faculty: Richard Miller, Clemson University
Student: Shervin Shoai Naini, Junkui (Allen) Huang, Clemson University
Government: Denise Rizzo, Katie Sebeck, Scott Shurin, U.S. Army TARDEC
Industry: Arun Muley, David Blanding, Boeing Research & Technology

To achieve improved vehicle fuel efficiency, cooling system optimization remains one of the most important concerns in automotive design. In previous studies, traditional mechanical based cooling system actuators were replaced by computer controlled actuators (e.g., variable speed electric coolant pump, etc). The electro-mechanical components enabled the application of model based controllers to predict heat rejection needs and regulate the actuator’s operation to achieve them. Physics based nonlinear controllers offer significant improvements in both cooling power conservation and component temperature tracking.

Based on the knowledge gained with cooling system actuator control, the research team will investigate innovative cooling paradigms which utilize thermal buses to efficiently move and reject heat. A thermal bus is hereinafter defined as any device, whether passive or active, used to transfer heat from a given entity. This would include a range of possible devices from refrigeration systems, liquid based radiator cooling systems, heat pipes (described below), to passive advanced materials with high thermal conductivity. Heat loads (e.g., electric motor, battery bank, power electronic drive, internal combustion engine, etc.) will be interfaced with thermal buses to move the heat to advanced designed heat exchangers and then discharge to the ambient surroundings through either passive and/or active cooling methods.

Schematic of cooling system concept with heat source, thermal bus to move heat from thermal load to heat exchanger, and rejection to ambient environment through passive or active methods

The project will study the efficient movement of heat from the thermal generating loads to the ambient surroundings. The main points include:

  • Investigate a cooling system architecture which features a thermal bus structure created with advanced materials to facilitate thermal load heat transfer.
  • Emphasize passive, as well as active, cooling strategies to minimize thermal system power consumption for fuel economy gains.
  • Advanced cooling systems, with a thermal bus will facilitate component modularity, flexible in-vehicle component placement, and reduced actuator operation schedules.
  • Development of high fidelity mathematical models, created using computational fluid dynamics (CFD) methods in COMSOL or ANSYS will demonstrate composite structures with required thermal properties and will aid in designing high performance heat exchangers.

Select related publications from previous work:

  • Tao, X., Zhou, K., Hoffman, H., and Wagner, J., "An Electric Motor Thermal Management System for Hybrid Vehicles – Modeling and Control", submitted to the International Journal of Vehicle Performance – special issue on Recent Advancement in Vehicle Thermal Performance Management, September 2015.
  • Tao, X., Zhou, K., Ivanco, A., Wagner, J. R., Hofmann, H., and Filipi, Z., "A Hybrid Electric Vehicle Thermal Management System - Nonlinear Controller Design", proceedings of SAE World Congress, paper 2015-01-1710, Detroit, MI, April 2015.