AHULife

Within the framework of the Federal Ministry for Economic Affairs and Energy funded project EnEff:Luft (funding code: 03ET1223B), a simulation tool was developed at the Institute for Energy Efficient Buildings and Indoor Climate that enables the user to determine the annual energy requirement and the life cycle costs of air handling units (AHU). The calculation methodology is based on VDI Guideline 2067, which defines a comfort range for indoor air characterised by limit values for temperature and humidity. (see Figure 1) Depending on the condition of the outside air, the various functions of an AHU are addressed according to this comfort range, considering internal loads. Thus, the minimum energy required to condition the air to the nearest limit of the comfort zone is always calculated.

Figure 1 Subdivision of the h,x diagram into zones according to VDI 2067

Figure 2: RLT-System

Using hourly resolved weather data of the 15 climate zones of Germany in the test reference year 2010, the annual energy demand of the air conditioning system is simulated. By selecting the supply units, the final energy demand and, if relevant, the fuel requirement is also calculated. With VDI 2067, life cycle costs are calculated taking into account annual operating costs, price increase rates, and replacement investments. In this way, an economic evaluation of the combination of AHU and supply is possible at the same time.

The tool is freely accessible at: https://ahulife.eonerc.rwth-aachen.de