Investment

When calculating the economic indicators, the investment costs of the heat generator and the cold generator are taken into account. If you do not wish to include them in the calculation, enter the value "0" here. The demand-related costs are determined via the electricity price and the prices for heating and cooling supply, as well as the "annual increasein prices". The operational costs are calculated from the total investment costs and the factor for maintenance and repair, as well as the "annual increase in prices". The lifetime of the AHU, the district heat supply and the district cold supply corresponds to the selected observation period. The lifetime of the heat generators and the compression chiller are calculated according to VDI 2067 Part 1.

The acceptable indoor conditions define the comfort zone, which indicates the acceptable indoor air conditions in terms of temperature and humidity. Depending on the outside air conditions, different functions of the air handling unit are addressed. A representation of the comfort zone and the functional areas is shown below. Please note that an excessive limitation of the absolute humidity in its maximum value in combination with an excessive flow and return temperature of the cooling medium will result in the comfort conditions not being maintained. In this case, the dehumidification capacity is limited.

"The internal loads are divided into a thermal load and a humidity load. The thermal load results in a temperature increase in the room. This can either be specified directly or a thermal load is specified in the form of a base and timevariable load depending on the occupancy. The humidity load results in an increase of the absolute humidity in the room. It can be entered directly (see explanations below) or as a base and timevariable load depending on the occupancy. Here it must be defined how much humidity in kg/h is released into the room air. This is the orientation value that can be used: approx. 1.27 g/kg (air mass specific humidity load) Calculated from: Humidity output: 55 g/h/person estimated according to [1] (approx. 0.4-0.6 litre/9h/person) Air requirement: 36 m³/h/person (equivalent to approx. 43.2 kg /h) according to DIN EN 15251, air category 2 [1] Richter W.; Hartmann Th.; Kremonke, A; Reichel, D.: Gewährleistung einer guten Raumluftqualität bei weiterer im Auftrag des Bundesministeriums für Raumordnung, Bauwesen und Städtebau, January 1999"