WinTherm	A thermal modeling analysis software with full geometry, editing, analyzing and post-processing capability. It comes with a helpful tutorial . This is a demo of their current commercial release, so it will definitely have some features crippled. Most likely it will be the maximum nodes that can be solved for. Created by ThermoAnalytics
SINDA/FLUINT	A generalized Thermal/Fluid network analysis program. Also, download SinapsPlus on the same page which is a graphical user interface for Sinda/Fluint. This evaluation version is limited to 50 nodes (temperature points in thermal networks) and 10 lumps (control volumes in fluid networks). The SinapsPlus GUI has the "Save" disabled. Created by Cullimore & Ring Technologies
TAS	This is a general thermal modeling analysis software.It is a demo with the "Save" function crippled.The number of nodes is limited to 300. Created by Harvard Thermal Inc