Improved Mobile Air-Conditioning Greenhouse Gas Life Cycle Climate PerformanceRequest Quote

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Newly updated software from OTS supports the automotive industry in understanding and achieving reductions in CO2 emissions.

The next generation of the GREEN-MAC-LCCP software is here and available only through Optimized Thermal Systems.

The IMAC-GHG-LCCP software application estimates the total direct and indirect CO2 emissions for a vehicle’s mobile air conditioning (MAC) system over its lifetime. With this information, automobile manufacturers are able to make evidence-based design modifications, meet applicable standards, and select the most appropriate refrigerants to reduce the emissions of greenhouse gasses. The tool uses an approach similar to the prior automotive LCCP standard (GREEN-MAC-LCCP) but with a focus on simplicity and ease-of-use with a friendly, interactive graphical user interface (GUI).

We’ve Incorporated Several Significant Improvements


  • +  Simplified User Interface
    The primary motivation for developing the tool was to provide a simplified user interface. The previous GREEN-MAC-LCCP tool used Excel spreadsheets for all inputs, while the new model allows users to enter values via a WinForms interface, or upload from pre-established Excel templates.
  • +  Decreased Runtime
    The new tool dramatically reduces the calculation runtime. Users have results in less than five minutes, versus the 1- to 2-hour runtime of the prior GREEN-MAC-LCCP.
  • +  Weather Data Selection Expanded
    Pre-set weather data for numerous worldwide locations, reflecting recent increases in temperatures resulting from global warming, are included in the tool.
  • +  Simulation Flexibility
    User input options have been expanded such that calculations include the type of refrigerant, leakage rate, vehicle type, vehicle lifespan and climate conditions selected by city. Defaults for total driving distance per year, driving time per year, and vehicle lifetime can be changed based on user data for each city and/or system in the user interface.
  • +  Equations for Electric Compressors and Water-Based Systems
    The capability to address the use of electric compressors and water-based systems in MAC systems has been added in the IMAC-GHG-LCCP. This gives auto manufactures a stronger start in the transition to electric cars on a mass scale. With this new tool, capacity and power consumption inputs for a vehicle using an electric compressor can be entered for each combination of ambient temperature and vehicle speed, instead of ambient and compressor RPM as for a belt-driven compressor. This encourages the evolution of existing technologies and enables the testing of new MAC technologies. Also incorporated is support for systems with multiple evaporators, multiple chillers, and additional sources of power consumption beyond the compressor.
  • +  Meets SAE Standards
    OTS developed the IMAC-GHG-LCCP tool under the direction and guidance of the Society of Automotive Engineers (SAE) Interior Climate Control Steering Committee. The tool meets the requirements of the following standards:

    • SAE Standard J2765TM
      Procedure for Measuring System COP (Coefficient of Performance) of a Mobile Air Conditioning System on a Test Bench was written to describe how energy consumption input data should be collected and used into a life cycle model for MAC systems. Input data has been revised in the IMAC-GHG-LCCP tool to include compressor energy consumption and the COP is calculated internally in the model.

    • SAE Standard J2766TM
      Life Cycle Analysis to Estimate the CO2-Equivalent Emissions from MAC Operation describes the recommended inputs and calculations suggested for use in a typical LCCP model for MAC systems. The IMAC-GHG-LCCP tool adheres to the calculation methods prescribed in this standard.

    • SAE Standard J2727TM
      Mobile Air Conditioning System Refrigerant Emission Charts for R-134a and R-1234yf is used as the source for user inputs of leakage rate for each system. This leakage rate is then corrected for the average ambient temperature in each city based on a correlation developed by Clodic1.

    1Clodic, D. “Research study on the definition of the implementation of a method of measurement of annual leak flow rates (LFRs) of MAC systems,” January 2006.

* WCX, SAE J2765, SAE J2766 and SAE J2727 are trademarks of SAE International. SAE does not endorse or authorize the IMAC-GHG-LCCP software.

Interested in a demo or trial version? Contact us with any questions you have about the new software or to get further information about calculating life cycle climate performance for your application.

This new software encourages the evolution of existing technologies and enables the testing of new MAC systems in evaluating their life cycle climate performance.