Energy2D, a multiphysics simulation program based on computational physics and combining particle dynamics, models all three modes for heat transfer: conduction, convection and radiation. Energy2D runs fast on most computers, eliminating the need to switch between preprocessors and solvers and postprocessors that are usually required for computational fluid dynamics simulations. It allows you design "computational experiment" to test a hypothesis or solve a problem in engineering without resorting complex mathematics. There are also plans to support different fluid types and incorporate other types energy transformations. Energy2D's conduction is very accurate, but its convection and radioactivity parts are not. Energy2D should therefore be considered qualitative in cases involving convection and/or radiation. Energy2D has been used in more than 40 scientific publications.