The THERMOSYS 4 Toolbox for MATLAB/Simulink® is a suite of simulation tools for analyzing the behavior of air-conditioning and refrigeration systems (both steady-state and time-dependent). It was developed at the University of Illinois at Urbana-Champaign through sponsorship by the Air-Conditioning and Refrigeration Center (ACRC) and is distributed by CU Aerospace.

Key benefits include:

• Nonlinear models suitable for simulation and control design of multi-phase fluid dynamics associated with subcritical air-conditioning and refrigeration systems
• Capability to simulate transient dynamics, including startup-shutdown dynamics
• Built-in refrigerant properties for R134a and R404A
• Open architecture code suitable for customization.