Project Synopsis

Support inventor in efforts to commercialize new refrigerant products by generating expected physical properties through the use of computer simulation models.

Project Summary


The client is an independent inventor developing novel refrigerant mixtures for use in automotive air conditioning systems and residential refrigerators.  These refrigerant mixtures must satisfy Underwriters Laboratories Inc. (UL) Standard for Safety for Refrigerants, UL-2182, before they can be sold for use by the public.  Process Engineering Associates, LLC (PROCESS) was contracted by the client to support the application for UL-2182 listing.  PROCESS utilized its licensed commercial computer process simulation software, Chemstations’ CHEMCAD, to perform a series of progressive flash calculations in order to simulate a leaking refrigerant canister.  The resulting vapor and liquid compositions were provided to the client and Underwriters Laboratories for evaluation for flammability and dispersal in air.

PROCESS performed the following tasks in support of this project:

  • Built the client’s refrigerant mixture into a ChemCAD simulation and modeled a “leaking” canister per the requirements of UL-2182, Section 5.3 – “Fractionation determination by computer modeling”.  This involved:
      • 50+ flash unit operations linked in series that reduced the flash pressures at constant temperature until prescribed (by UL-2182, Sections 5.1.3 and 5.1.4) amounts of material had vaporized, or “leaked”, from the liquid.  These pressure reductions (“leaks”) were continued until reaching atmospheric pressure or vaporizing all of the liquid.
      • 5+ flash unit operations in series that reduced the flash pressures and allowed the liquid temperature to vary with reducing pressure until prescribed (by UL-2182, Sections 5.1.3 and 5.1.4) amounts of material had vaporized, or “leaked”, from the liquid.  This simulation was performed to demonstrate the effect of changing temperature on the composition of the leaking vapor.


  • Utilized the ChemCAD model to determine the vapor densities of the original refrigerant mixture, each individual component, and air at various temperatures.  This data was used to determine whether the refrigerant mixture and its individual components will rise, settle, or remain stagnant if leaked into ambient air.
  • Summarized the modeling results in an Excel spreadsheet.  Vapor and liquid compositions at each successive flash step (successive amount “leaked”) were presented in tabular form.  Vapor composition was plotted versus flash step and versus pressure for all of the vapor components.  Refrigerant vapor and air densities were presented in tabular form versus ambient temperatures ranging from 30°F to 100°F.
  • Supported the client’s listing application by interfacing with UL officials to answer questions and discuss the results of the computer simulations.

Industry Type

  • Automotive Production

Utilized Skills

  • Physical properties estimation
  • Process modeling

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