This is a project I did for a company called TFDesign. The software is used to calculate certain parameters of a Heat Exchanger given certain specifications. The calculation runs over a given amount of heat exchanger rows to help the user determine the optimum design. The project was written in java to enable its use over multiple platforms. However, the software is not open source, but screenshots are available on this page.
The program has the ability to calculate 1 of 8 parameters given the other 7 parameters. This helps to iteratively tweak and optimize the design. The first image shows the input panel for the remaining variables with the variable to be calculated disabled. Other parameters are also changeable such as the type of radiator eg. Water to Air, Oil to Air or Air to Air, the core type as well as the number of passes.
When a calculation is executed on a certain parameter the program outputs the parameter value for different amounts of stacked cores as seen in the second image. If the calculation runs over a specified limit or into an error it gets displayed as seen in the same image.