Calculation and Simulation Energiebuendel 

Calculations and Simulations

Many colleagues have other problems apart from very tricky and special calculations for energy savings. In these questions we support you with calculations and simulations in your activities as energy consultant. Simply benefit from our long-standing experience and our specialised knowledge.


Using WUFI Pro we offer one-dimensional simulations for the hygrothermal examination of construction parts.

This is often used for interior insulations, timber constructions with external vapour-impermeable sheets like flat roofs, insulation works in the building stock especially with special boundary conditions, like wet walls or beams, high indoor humidity etc. The calculations are based on EN 15026 in conjunction with DIN 4108-3 and the appropriate WTA recommendations.

Building equipment simulations

With the very capable Polysun-Designer software we offer simulations of building equipment for heating, refrigeration, DHW, and electrical power supply. In addition to classical heating and thermal solar systems, this also includes more complex systems, such as combined electrical and thermal solar panels, combined heat and power systems, power supply of buildings and locally charged electrical vehicles. The actual locally usable power of PV systems can be assessed for heat pumps, refrigeration systems and, for example, household electricity with matching profiles. Tell your client what they can really expect.

Meteorological data

From time to time you may lack just the right weather data set to get good results with your calculation. In this case we can help with global meteorological data sets generated by the Meteonorm software. This may also include individual shading situations.

Energy balances with thermal bridges and summer heat protection

We support you in the calculation of (parts of) energy balances, like the Passive House Planning Package (PHPP), new energy performance of building calculation standards (DIN V 18599, EPB standards), as well as detailed thermal bridges or summer heat protection simulations. Especially in difficult cases which you cannot solve easily. We are experts for these cases and offer training on your projects as well.

Simulation or calculation?

Simulations are calculations with variable, transient boundary conditions and a fragmented analysis focus.

These are from the above-mentioned software tools, primarily WUFI and Polysun. We also simulate with Dämmwerk to analyse the thermal behaviour of rooms under summer conditions. Previously we used a very simple and ideal programme for the room analysis, called PC-Helios, but unfortunately it is not supported anymore.

Graph of a simulation of room themal conditions
Graph of a simulation of room thermal conditions: DÄMMWERK
Calculation of the thermal bridge of a balcony connenction
Calculation of the thermal bridge of a balcony connection, graphic: DÄMMWERK

The usual calculations of thermal bridges are not considered simulations. These do use a finite element mesh for a fragmented analysis focus, but also use fixed boundary conditions to calculate a stationary state. An exception might be the calculation of a thermal bridge at the base perimeter of the building with dynamic weather data outside, to consider the influence of the thermal capacity of the soil. This is currently not the norm in Germany.

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Dipl.-Ing. Friedemann Stelzer

Founded in Cologne in 1998, the consultants have been based in Reutlingen since 2007 and offer their services throughout Europe.


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