From the beginning, the Sauna program was created exclusively for the thermal analysis of electronic components and systems. All menus, material libraries and assembly properties were created with this one goal in mind.

Building your model is intuitive and easy. A model is constructed using the building block assemblies of plates and circuit boards. To create a plate you simply define the plate dimensions and choose the material and surface types from menus. In just seconds, the plate appears on the computer screen. You don't have to type in any thermal conductivities or other properties. Furthermore, if you wish to add fins to either side of the plate, this can be accomplished with a single command.

A simple heat sink model will appear as shown in the picture on the right. In this picture, which is a wireframe view, you can see the array of nodes and resistors that Sauna uses to define the model characteristics. Although Sauna uses the classic thermal network method, you almost never enter values for the thermal nodes, resistors and capacitors. Sauna calculates model values for you automatically, based on materials and dimensions that you specify. Sauna creates a smart model which is easy for you to check and modify.

Of course, it is also useful to have a realistic image of your model, instead of the wireframe view. For this Sauna provides "shade mode". At any time, a single mouse click will switch the display into shade mode, producing a shaded, perspective view of the model. The picture on the left shows the heat sink model in shade mode. If you wish, it is also possible to perform dynamic view rotations and progressive zooms.

Creating a circuit board is equally easy. You use menus to select the number of layers, copper weight, and copper coverage. Very quickly, a complete board model is created and drawn on the screen. All the necessary engineering data, including a library of standard semiconductor packages, is built into the Sauna program.

After creating model elements for the plates and boards, Sauna's advanced join command is used to provide thermal connections. Joining is effortless. You start by choosing the thermal interface type from a menu. Then, you use the mouse to select the appropriate boards and plates. After verifying that there is no interference or air gaps, Sauna automatically adds the necessary thermal connections. Sauna also provides specialized commands for quickly creating a 6-sided box as well as commands for creating boards and interior walls inside a box. These are all common tasks when modeling an electronic system, so Sauna makes these tasks easy and error-free.

Convection and radiation heat transfer are both nonlinear, temperature-dependent phenomena. With conventional thermal analysis packages, dealing with these dissipation modes can become a very time consuming and error prone process.

With Sauna, however, convection and radiation coefficients are automatically calculated for you. You simply connect "float" resistors between the boards and plates and the desired internal or external ambients. For convection, both natural and forced air cooling are available. For radiation, simple (black body) radiation is supported as well as gray radiation inside an enclosure, which includes automatic calculation of view factors.

Sauna uses advanced sparse matrix methods to dramatically reduce model calculation time. For steady state problems, calculation times are typically measured in seconds. Even for transient problems, model calculation times are usually just a minute or two. With Sauna's speed of model creation and temperature calculation, a complete model can be built and analyzed in less time that an average coffee break.

To help you interpret transient temperature data, Sauna incorporates a comprehense plotting utility (see picture on right). "Temperature vs. time" data can be plotted on the screen, printed, or exported to other applications (Postscript, BMP, or spreadsheet format). Temperatures charts can also be prepared. Sauna provides all the tools you need to interpret and document the results of the transient calculation.

With Sauna, you can create and analyze a thermal model in a matter of minutes. However, many times you will find that temperatures are not at acceptable levels. An important test of any modeling program is whether modifications are easily performed.

Sauna is the premier tool for what-if thermal design. Powerful edit commands make it a snap to change a housing from ABS plastic to aluminum alloy. Moving heat sources and repositioning circuit boards is equally easy. It is equally easy to change from natural to forced air cooling, or to modify the air velocity. With all these editing features, combined with Sauna's rapid calculation times, it is possible to quickly evaluate a whole series of alternatives. The final result: an optimized final design. And, of course, a savings of many man-hours of engineering time.