Utilization of Ice Storage in Secondary Loop Automotive Air-Conditioning Systems

Due to the influence of energy use on electric vehicle range, latent energy storage options could be used to increase thermal comfort and decrease energy consumption during driving. This study focuses on the implications of thermal storage on transient performance of a typical secondary loop system and a combined secondary loop with ice storage system. The use of ice storage in assisting the vapor compression cycle during cabin pull-down and continued cooling, as well as cooling during compressor off periods was experimentally investigated. It was found that the ice storage system was able to decrease energy consumption during pull-down by about 20% and decrease time to comfort by about 15% compared to a regular secondary loop system. Ice storage showed superior performance for preventing cabin warm-up and reducing cabin humidification during off-cycle periods of up to 15 minutes, while showing the potential to either replace or severely reduce the use of a vapor compression system during daily commutes when used in combination with cabin preconditioning. While the current ice storage box was found to be oversized and the heat exchanger could be optimized further, experimental results give an outlook on the possible use of ice storage as an effective method of reducing air conditioning energy and enhancing thermal comfort.