Development of a Tool for Estimating the Life Cycle Climate Performance of MAC Systems 2019-01-0611
Climate change is a global issue affecting every industry. Automotive companies have been working to address this issue by reducing the greenhouse gas emissions of their vehicles and improving the efficiency of MACs (mobile air conditioning systems). Life-cycle climate performance (LCCP) is a comprehensive metric for estimating the CO2-equivalent emissions produced by the construction and operation of a MAC system. Many companies and organizations have conducted LCCP for their vehicles using various software tools. The IMAC-GHG-LCCP model is a comprehensive software tool that follows a similar approach as the current automotive LCCP standard, GREEN-MAC-LCCP, but with a focus on simplicity and ease-of-use. The tool has support for water plumbing, multiple compressors and evaporators, and user-defined refrigerants. Features including improved project model saving and loading and error handling have been added for software ease-of-use. Vehicle usage data for each city including vehicle lifetime, driving distance, and driving duration are open for user edit. Inputs to the software include refrigerant leakage data, MAC capacity and power consumption data, vehicle component mass input data, fan data, updated weather data, and drive cycle data to calculate the indirect and direct CO2-equivalent emissions for a given vehicle in each selected city. Curve fits of the cooling capacity and power consumption of a standardized set of MAC tests are used to estimate the performance of the MAC at a range of different engine speeds and ambient conditions. The emissions of the vehicle are calculated at each time step of the selected drive cycle and a results report is generated. The results report provides the calculated direct and indirect emissions for each city. A model example estimating the effects of improving the efficiency of the MAC system on the direct and indirect emissions of a vehicle is presented.
Adam Rhoads, William Hill
Optimized Thermal Systems Inc., Macrae LLC