調湿デバイスによる電気自動車の冬季航続距離改善：Ceramic Humidity Regulator（CHR）

齋藤　浩貴・伊原　幸男・太田　一・酒井　直希（NGK）

EVは冬季暖房により航続距離が大幅に低下することが課題である．暖房効率低下の1つに，窓ガラスの防曇目的の換気による熱損失が挙げられる．除湿材とセラミックPTCヒーターを一体化したデシカントデバイス（CHR) を開発．車両試験ではオートエアコンモードと比較して暖房電力25%低減確認し，冬季航続距離改善が期待できる．

Holistic Evaluation of Electric Vehicle Efficiency: Benchmark Study of R-474A, R-1234yf, and R-744 Using Digital Twin Simulation

Christian Macrì･Álvaro de León･Felix Flohr (Daikin Chemical Europe)

The transition to battery electric vehicles (BEVs) comes with several challenges such as energy efficiency and the resulting driving range. The thermal management systems play a pivotal role ensuring optimal energy efficiency and passenger comfort. Refrigerants play a crucial role, as their properties impact heat exchange efficiency and overall energy consumption. This study presents a comprehensive benchmarking of the new refrigerant R-474A against R-1234yf and R-744 in a BEV thermal management system. A simulation has been conducted, beginning at system level, progressing to vehicle level, and concluding with evaluations under transient driving conditions across various driving patterns and temperature profiles.

Experimental Study and Simulation on the Performance of a Heat Pump System with Novel Low-GWP R474A for New Energy Vehicles

Yunlong Zhang (Shanghai Jiao Tong University)･Nie Hao (Daikin Fluorochemicals)･Negishi Yasutaka･Ajioka Shohei･Bunno Asuka (Daikin Industries)･Yamamoto Kei (Daikin Fluorochemicals)･Jiangping Chen･Binbin Yu (Shanghai Jiao Tong University)

This study investigates the cycle performance and system behavior of a novel refrigerant, R474A in the heat pump for new energy vehicles. Results show under both cooling and heating conditions, R474A demonstrated strong performance: a COP up to 3.67 under light-load conditions, a maximum cooling capacity of 7004.5 W, and a maximum heating capacity of 6044.5 W. Comparative analysis revealed that R474A outperforms R134a and R290 in terms of cooling and heating capacity across conventional and extreme operating conditions, while maintaining a higher COP than R290. Notably, R474A overcame the operational limitations of R134a at extreme low temperatures and exhibited minimal temperature non-uniformity from glide effects, ensuring satisfactory thermal comfort. These findings highlight R474A's significant potential as a sustainable alternative refrigerant for NEV heat pump applications.

Testing of Novel Refrigerants in an Indirect Automotive Heat Pump Module
-Drop in Comparison of R-1234yf, R-474B, R-491A, and R-290-

Miloš Fojtlín･Ján Tuhovčák･Tomáš Mrkvica (SATTELO)

Driven by electric mobility and mobile machinery needs, the market demands efficient thermal management with refrigerants that work across climates, meet low-GWP and PFAS-free requirements, and require minimal system changes. This study evaluates two novel blends, R474B and R491A, as drop-in candidates versus common automotive refrigerants. Laboratory tests under heating, cooling, and high-load conditions show performance can be limited by existing equipment and safety constraints, though cooling and dehumidification needs were met. Overall, the results show the new refrigerants are technically viable and offer a promising path for future EV thermal management.

車載電動コンプレッサ短絡放電エネルギー推定のためのシステムシミュレーションモデルの構築

長井　謙悟・中山　諒人・増田　樹（名古屋大学）・根岸　泰隆・文野　明日香・臼井　隆（ダイキン工業）・重松　浩一・今岡　淳・山本　真義（名古屋大学）

HFO冷媒は高性能かつ低GWP特性により注目される．一方，コンプレッサ内部で短絡放電が発生し，エネルギーを受けると自己分解を誘発しうる．本稿では，実機短絡試験にて放電波形とエネルギーを測定し，分解調査から得た回路素子値を用いて，短絡放電エネルギー推定のためのシステムシミュレーションモデルを構築した．