Modelica.Fluid.Examples.TraceSubstances

Library demonstrating the usage of trace substances

Information

Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).

Package Content

Name	Description
RoomCO2	Demonstrates a room volume with CO2 accumulation
RoomCO2WithControls	Demonstrates a room volume with CO2 controls

Modelica.Fluid.Examples.TraceSubstances.RoomCO2

Demonstrates a room volume with CO2 accumulation

Information

This example consists of a volume with a carbon dioxide concentration that corresponds to 1.519E-3 kg/kg, which is equal to 1000 PPM. There is a fresh air stream with a carbon dioxide concentration of about 300 PPM. The fresh air stream is such that the air exchange rate is about 5 air changes per hour. After 1 hour of ventilation, the volume's carbon dioxide concentration is close to the concentration of the fresh air.

The nominal value for the trace substance is set to C_nominal={1.519E-3}. This scales the residual equations that are used by the solver to the right order of magnitude.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica.Fluid.Examples.TraceSubstances.RoomCO2WithControls

Demonstrates a room volume with CO2 controls

Information

This example illustrates a room volume with a CO2 source and a fresh air supply with feedback control. The CO2 emission rate is proportional to the room occupancy, which is defined by a schedule. The fresh air flow rate is controlled such that the room CO2 concentration does not exceed 1000 PPM (=1.519E-3 kg/kg). The fresh air has a CO2 concentration of 300 PPM which corresponds to a typical CO2 concentration in the outside air.

The CO2 emission from the occupants is implemented as a mass flow source. Depending on the activity and size, a person emits about 8.18E-6 kg/s CO2. In the model, this value is multiplied by the number of occupants. Since the mass flow rate associate with the CO2 source model contributes to the volume's energy balance, this mass flow rate should be kept small. Thus, in the source model, we set the CO2 concentration to C={100} kg/kg, and scaled the mass flow rate using

  m_flow = 1/100 * nPeo * 8.18E-6 kg/(s*person)

where nPeo is the number of people in the room. This results in a mass flow rate that is about 5 orders of magnitudes smaller than the supply air flow rate, and hence its contribution to the volume's energy balance is negligible.

The nominal value for the trace substance is set to C_nominal={1.519E-3}. This scales the residual equations that are used by the solver to the right order of magnitude.

Extends from Modelica.Icons.Example (Icon for runnable examples).