Customized Heat Exchangers with a Sizing Software

In order to supply its clients with the best possible heat exchanger solutions, Vahterus designs the exchangers together with the client from beginning. In addition to functional requirements, heat exchangers must fulfil statutory pressure equipment regulations, as well as the client’s own specific requirements. In order to do this, Vahterus has invested heavily in developing its own sizing software.

One of the key aspects in developing sizing software has been our own heat transfer and mechanical testing, which have been used to examine performance of heat exchangers, mechanical durability of plate packs, and the usage limits of heat exchangers in different applications. Client feedback and in particular the data measured at different applications have also been valuable when the software parameters have had to be adjusted to match reality. Together with the knowledge of the heat transfer theory and expertise in pressure equipment design, this data has laid the foundation for developing the software.

The structure that makes size customisation possible

The Sizing software covers 14 applications, including for example liquid-liquid, liquid-gas, evaporators, condensers and cascade applications. Even though different Plate & Shell heat exchangers may look similar in different applications, each application has its own specific features and therefore separate calculation screens for each application are required.

All Plate & Shell application programmes are divided into two parts: thermal- and construction design. In thermal design part the thermal input values, fluids and basic construction are selected. The software calculates the required exchanger size, number of plates, flow velocities and other necessary sizing values.

In the construction design part, the software checks if it is possible to manufacture a heat exchanger that meets the parameters defined in the thermal and construction de- sign. The software can calculate construction specifications for selected Plate & Shell heat exchanger according to the requirements of the Pressure Equipment Directive (PED) or ASME standards. In the background of the software there is a large amount of pre-calculated type series that determine the dimensions of the main components and materials.


The programme’s purpose is to allow flexible and accurate calculations for Plate & Shell heat exchangers. Another important function is to automate the quotation pro- cess so that we can quickly and flexibly send our clients the quotation documentation detailing the heat exchanger that we intend to offer them.

The heat exchanger specification sheet lists a heat exchanger’s technical specifications consisting of thermal design values and the basic construction data such as main materials, pressure class, flange data (if any), coating and classifications etc. The Sizing program also allows users to output a preliminary technical drawing of the heat exchanger. The latest major advancement in this area has been the development of the new 3D modelling system. The previous 3D modelling software was replaced with an automatic drawing programme built upon the Inventor software, making it possible to create more accurate AutoCAD images than before. The Sizing software can be used to order from Vahterus drawing server the exchanger’s technical drawings in PDF and DWG formats as well as a three-dimensional ‘Step’ model that can be integrated with client’s own 3D models. The picture above is an example of a 3D model produced by the software. The ‘Step’ model is compatible with most 3D programmes. The Sizing software can also print out a list of a heat exchanger’s components, which makes it often possible to order the exchanger’s main components before the product plans are finalised.