John J. Meyer

Reduction in Vehicle Temperatures and Fuel Use from Cabin Ventilation, Solar-Reflective Paint, and a New Solar-Reflective Glazing

An analysis to determine the impact of reducing the thermal load on a vehicle using solar-reflective paint and glazing.

Simulated performance and cofluid dependence of a CO2-cofluid refrigeration cycle with wet compression

Abstract Recent experiments demonstrate the viability of a low-pressure CO 2 -cofluid compression refrigeration cycle in which CO 2 and a non-volatile cofluid are circulated in tandem and co-compressed in a compliant scroll compressor. This work explores the theoretical performance limitations of such a cycle operating under environmental conditions representative of automotive air conditioning and studies the dependence of this performance on the properties of the CO 2 -cofluid mixture. The vapor–liquid equilibrium and thermodynamic properties of the mixture are described using a previously reported activity-coefficient model. A coupled system of physically based equations that allows for consideration of both ideal and real hardware components is used to represent the system hardware and its interaction with the environment. The system efficiency is analyzed in terms of entropy generation rates in the various hardware components; entropy generation in the internal heat exchanger—a component required to achieve sufficiently low cooling temperatures—strongly influences overall system efficiency. The vapor pressure of the CO 2 -cofluid mixture and the heat of solution of CO 2 in cofluid have large and somewhat independent contributions to the system performance: lower saturation pressure lowers the optimal operating pressures at fixed CO 2 loading, while increasingly negative heat of solution contributes to higher specific refrigeration capacity and efficiency.

Range Extension Opportunities While Heating a Battery Electric Vehicle

The Kia Soul battery electric vehicle (BEV) is available with either a positive temperature coefficient (PTC) heater or an R134a heat pump (HP) with PTC heater combination [1]. The HP uses both ambient air and waste heat from the motor, inverter, and on-board-charger (OBC) for its heat source. Hanon Systems, Hyundai America Technical Center, Inc. (HATCI) and the National Renewable Energy Laboratory jointly, with financial support from the U.S. Department of Energy, developed and proved-out technologies that extend the driving range of a Kia Soul BEV while maintaining thermal comfort in cold climates. Improved system configuration concepts that use thermal storage and waste heat more effectively were developed and evaluated. Range extensions of 5%-22% at ambient temperatures ranging from 5 °C to −18 °C were demonstrated. This paper reviews the three-year effort, including test data of the baseline and modified vehicles, resulting range extension, and recommendations for future actions.