Distributed air-conditioning system for multi-machine parallel collaborative operation in electric vehicles

Abstract

Electric buses often face significant energy-consumption challenges, as air-conditioning units alone consume over 30% of such buses’ battery power at maximum capacity. To address this problem, we propose a distributed collaborative cooling method employing multiple refrigeration devices to reduce energy consumption by electric vehicle air-conditioning systems. Initially, numerical analysis is used to determine the heat load inside a vehicle, thereby facilitating the establishment of power and component models for multiple small refrigeration devices. Furthermore, a hybrid approach utilizing cameras and thermal infrared sensors is employed to detect passenger occupancy within a vehicle. The vehicle’s interior is divided into three zones—front, middle, and rear—each of which is equipped with a small refrigeration unit, rather than using a conventional single-unit configuration. The concept of the relative number of people ratio is introduced to gauge the requisite cooling capacity within the vehicle. Additionally, a novel method is proposed for pulse width modulation control of a refrigeration compressor, predicated on a comparison between the number of passengers and the interior temperature. High-temperature tests are conducted on an electric bus to evaluate the cooling performance and energy consumption of the novel refrigeration system across varying passenger loads. The results demonstrate that the system achieves the desired cooling effect while reducing energy consumption by up to 83.6% compared with traditional electric vehicle air-conditioning systems, thereby effectively extending the range of electric vehicles.