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Etude et amélioration d’une pompe à chaleur pour véhicule électrique en conditions de givrage

Abstract : In the electric vehicle (EV) development context, the choice of heat pumps (HP) for cabin heating is becoming more popular due to their high efficiency compared to electric heaters. However, under some operating conditions, frost forms on the HP evapo-condenser causing a dramatic drop in the system performances until the system cannot operate. Hence, this work aims at developing a HP for EV which remains efficient under frosting conditions ultimately, to improve the EV range in the winter. This requires the design of a frost-resistant heat exchanger (HX). First, to improve the HX design, a dynamic and pseudo-3D model under frosting conditions of a typical HX for cars has been developed. A simple and accurate frost growth sub-model has been established by studying the various modeling assumptions found in the literature. Then, at the HX level, the key point has been to predict the air pressure losses, via the consideration of the maximum local frost thicknesses and the development of a correlation considering frost, in order to predict the drop of airflow and therefore the drop of the HX cooling capacity. Then, the model of the HX coupled with the fan has been validated experimentally. Using the model, a numerical study has been conducted and two innovative concepts have been established: one with wavy upstream extending fins and the other with crossed passes of refrigerant. Two prototypes were fabricated, using a reference HX taken from the Renault Zoé, and then tested. The best of the two HX, the one with upstream extending fins, was mounted on a VE and compared to the reference case. The prototype allowed extending the system operation by 2.5 times approximately. Finally, a HP model under frosting conditions was built and integrated into a EV model. It appeared that, for an EV with a range of approximately 140 km without heating, the HP frosting degrades the autonomy by about 15% at 0°C and 90% humidity, which was reduced to 3% via the use of the innovative HX prototype with wavy upstream extending fins.
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https://pastel.archives-ouvertes.fr/tel-03081279
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Submitted on : Friday, December 18, 2020 - 9:59:58 AM
Last modification on : Sunday, December 20, 2020 - 3:04:58 AM

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2017PSLEM083_diffusion.pdf
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  • HAL Id : tel-03081279, version 1

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Florent Breque. Etude et amélioration d’une pompe à chaleur pour véhicule électrique en conditions de givrage. Energie électrique. Université Paris sciences et lettres, 2017. Français. ⟨NNT : 2017PSLEM083⟩. ⟨tel-03081279⟩

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