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The PHLuft Tool consists of the following parts:

  • Heat output
  • Ground heat exchanger
  • Heat exchanger

This tool is intended to support the ventilation planner of Passive House ventilation systems in his work.

Heat output

With the help of this part of the Tool, you can calculate the supply air temperature after a ventilation duct. Normally, a supply air duct is composed of a number of horizontal or vertical sections. To calculate the supply air outlet temperature at the supply air valve, you must therefore proceed section by section, starting after the post-heating coil. The calculated outlet temperature of the first section is therefore entered as the inlet temperature of the next section, and so on. In the case of vertical ventilation ducts, you must note that these are again divided into several sections if the free convection on the outer surface of the duct is interrupted, e.g. by storey ceilings. A distinction is also made between flow from top to bottom and vice versa.

Earth heat exchanger

With the main menu item Earth duct, you reach the part for the calculation of earth heat exchangers. This allows you to calculate the heat output of earth heat exchangers in through-flow according to Tichelmann or in meander form. For input into the Passive House Project Planning Package (PHPP), you need the annual average heat supply rate, which is also output with this Tool. In addition to calculating the results, you can also output the temperature curves graphically.

Heat exchanger

This part of the Tool calculates the temperatures and heat provision rates of counterflow heat exchangers. The user only enters the outdoor temperature, the extract air temperature and the air temperature at the installation site of the heat recovery unit. The transmission heat flows through the casing are taken into account.

PHLuft Tool

Download the tool here.

This tool was developed within the framework of the “Arbeitskreis Kostengünstige Passivhäuser - AK17“

Installation guideline: Unzip the ZIP file. If you do not have a programme for processing ZIP files, you may download a free test version of the WinZip programme from

Click here to go back to the main menu.

planning/phluft.txt · Last modified: 2022/09/06 09:43 by