The synergy of research, teaching and industry
Driving the Future Through Innovation…Safely!
Modeling and Testing of a Thermoelectricbased Child Safety Seat Cooling System Eleanor Walters, MPH, CHES January 24, 2012
Eleanor Walters
Modeling & Testing a CSS Cooling System
synergy of research, teaching, and industry
Focus The safety research arm of the Clemson University International Center for Automotive Research (CU-ICAR) Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
Mission
To improve the safety of the automotive transportation environment through a systemic analysis of the human-vehicle-road system Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
a powerful idea To provide interdisciplinary safety research focusing on the transportation environment through analysis of the human-vehicle-road system and to develop evidence-based countermeasures and products
HUMAN
Human Factors Data
Environmental Data
Fundamental Understanding
VEHICLE
ROAD/
ENVIRONMENT
In-vehicle Instrumentation and On-road Data
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
Keeping Kids Safe In and Around Cars • NHTSA • Kids and Cars • San Francisco University – Dept. of Geosciences • Safe Kids • Children’s Hospital of Philadelphia
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
Background Research and education to reduce unsafe behaviors among parents and caregivers when transporting children
• Child Passenger Safety Inspection Station • Child Entrapment in South Carolina
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
Background Research to reduce unsafe conditions in vehicles when transporting children
• CU-ASRI Child Passenger Safety Program • Department of Mechanical Engineering
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
IFAC Symposium on Advances in Automotive Control • Lusso, R., Jensen, M., Wagner, J., Walters, E., & Alexander, K. Automobile safety child seat entrapment and mechatronic warning system, Proceedings of the Fifth IFAC (International Federation of Automatic Control) Symposium on Advances in Automotive Control, Monterey Coast, CA.
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
Smart Safety Seat Design System • Analyzes threatening levels of interior and exterior temperatures to determine danger to an occupant • Safety threat level determines response of system to enhance occupant’s well being • Onboard sensors, actuators, and control logic integrated to seating system
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
• Dedicated sensors integrated into seat and communicates with vehicle ECU • Actuators used to administer warning and rescue devices as controlled by onboard CRS • Controller interfaces with ECU to identify 5 adverse conditions and appropriate response Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
•
1995 red Geo Prism
•
No window tint or film
•
Grey cloth interior
•
No shade
Test Configuration • All Day Soak – temperature recorded every 30 minutes from 8:00 am to 5:30 pm on 5 sunny days in August •
Mid-Day Soak – temperature recorded periodically for 3 hours after interior cooled to 78oF. 5 trials starting at either 12:45 pm or 2:45 pm on 5 sunny days in August
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
Experimental Results • All Day Soak – deadly interior temperature of 104.3o F reached after 90 minutes with exterior temperature of 85oF; maximum interior temperature 153.5oF with maximum exterior temperature 98oF by 3:00 pm • Mid-Day Soak - deadly interior temperature of 104oF reached within 15 minutes of each start time; maximum interior temperature reached within 3 hours
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
Institute of Electric and Electronics Engineers Transactions on Vehicular Technology • Finn, J., Wagner, J., Walters, E., Alexander, K. (2011). An Integrated Child Safety Seat Cooling System – Modeling and Test. Institute of Electric and Electronics Engineers Transactions on Vehicular Technology, [VT-2011-01238 in final publication review].
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
Child Safety Seat (CSS) Cooling System Research Questions • Can an emergency system be developed to delay interior cabin temperatures rising to fatal levels? • Can that system be integrated into a CSS and not require any additional steps to correct CSS installation?
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
CSS Cooling System Literature Review • Kakuta et al.: Validated human thermoregulatory model • Thornton and Nair: Demonstrated the effects of biological parameters on human thermal model accuracy • Yokoyama et al.: Developed and validated model of human thermal system
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
CSS Cooling System Literature Review (cont.) • Riffat and Qiu: water-cooled heat sink • Chen and Gwilliam: fluid heat exchangers • Wang and Crane: cooling system powered by a thermoelectric module
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
CSS Cooling System Literature Review (cont.) • Dabney and Elrod: patented thermoelectric system of heated or cooled elements to maintain ambient temperature for a child in CSS • Finn et al.: developed differential equations to describe thermal circuit behavior similar to CSS cooling system
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
CSS Cooling System Mathematical Models • Thermal response of system analyzed by considering thermoelectric devices, child occupant, and vehicle cabin • Thermoelectric equations integrated into child seat and cabin environment
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
CSS Cooling System Mathematical Models (cont.) • Human thermal behavior simulated using a fixed parameter model and then developed into a thermoregulatory representation • Cabin temperature modeled using a lumped parameter approach and properties representative of typical passenger vehicle
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
CSS Cooling System Supply Design • Convective thermoelectric air conditioning system into a standard CSS • Battery power to provide localized convective and evaporative cooling • Cooling system could be integrated with alarms
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
CSS Cooling System Limitations • Pseudo child • Rapid dehydration and high body temperature • Vehicle cabin differences
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
Modeling & Testing a CSS Cooling System
CSS Cooling System Conclusions • Mathematical model reproduced in experimental situation with similar results thus proving the basic concept • Fatality temperatures delayed with cooling system; severe dehydration and hyperthermia likely • Interior vehicle temperatures higher than expected
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Eleanor Walters
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CSS Cooling System Future Work • Explore evaporative cooling issues • Increase thermoelectric cooling capacity to extend survivability time • Minimize occurrence of emergency situations • Would an emergency system be a marketable feature for a CSS?
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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Modeling & Testing a CSS Cooling System
a bold future
Driving the Future Through Innovation … Safely Dr. Kim E. Alexander, Executive Director Catherine Murphree, Public Relations Manager Dr. Philip Pidgeon, Assistant Director for Research Eleanor Walters, Assistant Director for Outreach C
T l (864) 656 6876 / k l
Presented January 24, 2012 at the TRB ANB45 Annual Meeting
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