The Performance Improvement and Optimum Control of the Transcritical Co2 Air Conditioning and Heat Pump System Used in the High-Speed Railway Vehicles

Abstract

To effectively respond to the goals of carbon neutrality and the Kigali Amendment, it is crucial to address the issue of refrigerant substitution in railway heat pump air conditioning systems. This article focuses on studying the challenges related to thermal management logic control when using CO2 as the alternative refrigerant for heat pump air conditioning in rail vehicles. The study includes the development of a comprehensive model of the entire cabin and heat pump air conditioning system cycle using the AMEsim simulation platform. An experimental platform was constructed to conduct relevant verification experiments. Through these experiments, it's concluded that the proposed model and logic are applicable and effective for rail vehicles. The unique operational conditions and requirements of railways necessitate distinct CO2 heat pump air conditioning requirements compared to passenger cars. The rail vehicles, characterized by high thermal load and inertia, exhibit slow temperature response rates. Conventional thermal management techniques employed in passenger cars often lead to frequent start-stop cycles of the compressor during dynamic vehicle operations. However, new system optimization and logic optimization were conducted for these special requirements. By implementing new thermal management strategies, the duration of compressor start-stop cycles was extended, aligning better with real-world practical applications.

Keywords: optimum control, railway vehicles, start-stop logic, transcritical CO2, Dynamic optimization