Humidity & Trace Gas Sensor (MA)

Measurement of humidity and the amount of gas impurities in a network of humid air.

blockType: AcausalFoundation.MoistAir.Sensors.HumidityAndTraceGas

Path in the library:

/Physical Modeling/Fundamental/Moist Air/Sensors/Humidity & Trace Gas Sensor (MA)

Description

The Humidity & Trace Gas Sensor (MA) unit measures the humidity and the amount of gas impurities in a network of humid air. There is no mass or energy flow through the sensor.

Ports W, Tw, and G output the measurement results on port A of humidity and gas impurity count, respectively. The Tw port is used when Measured moisture specification is selected as the parameter. Wet-bulb temperature.

The sensor readings correspond to the humidity and the amount of gas impurities in front of the node to be measured. For example, if port A of the Humidity & Trace Gas Sensor (MA) unit is connected to a node between pipe 1 and pipe 2 and humid air flows from pipe 1 to pipe 2, the humidity and amount of gas impurities measured at port A characterise the volume of humid air in pipe 1. If then the air flow changes direction and flows from pipe 2 to pipe 1, then humidity and amount of gas impurities measured at port A characterise the volume of moist air in pipe 2. If the humidity and the amount of gas impurities in the two volumes of moist air are different, the measured values change when the flow direction is changed. If two or more upward flows merge at a node, the measurement of humidity and the amount of gas impurities at the node represents a weighted average value based on perfect mixing of the flows.

Ports

Conserving

# A — sensor input
`humid air

Details

Humid air port, corresponds to the sensor input. Connect this port to the humid air network node where you want to measure humidity and gas impurities.

Program usage name

port

Output

# W — humidity
scalar

Details

Output signal port for measuring humidity. The measurement method is set by the parameters Measured moisture specification.

Dependencies

To use this port, select the Moisture checkbox and set the Measured moisture specification parameters to one of the following values

Relative humidity
Specific humidity
Water vapor mole fraction
Humidity ratio

Data types	`Float64`.
Complex numbers support	No

# G — gas impurity level
scalar

Details

Signal output port for measuring the amount of gas impurities. The measurement method is set by the parameters Measured trace gas specification.

Dependencies

To use this port, select the checkbox Trace gas.

Data types	`Float64`.
Complex numbers support	No

# Tw — wet bulb temperature
scalar

Details

Signal output port for measuring the temperature reading of a wet thermometer that characterises humidity.

Dependencies

To use this port, select the Moisture check box and set the Measured moisture specification parameters to Wet-bulb temperature.

Data types	`Float64`.
Complex numbers support	No

Parameters

# Moisture — switching on the output port for moisture measurement

Details

Checking this box enables the W or Tw output port to measure the value set by the parameter Measured moisture specification.

Default value	`true (switched on)`
Program usage name	`measure_moisture`
Evaluatable	No

# Measured moisture specification — moisture measurement method
Relative humidity | Specific humidity | Water vapor mole fraction | Humidity ratio | Wet-bulb temperature

Details

Sets the measurement method:

Relative humidity - W port signal equals relative humidity.
Specific humidity - The signal on the W port equals the specific humidity.
Water vapor mole fraction - the signal at port W is equal to the molar fraction of water vapour.
Humidity ratio - signal at port W equals water vapour content.
Wet-bulb temperature - signal on the Tw port is equal to the wet-bulb temperature.

Values	`Relative humidity` \| `Specific humidity` \| `Water vapor mole fraction` \| `Humidity ratio` \| `Wet-bulb temperature`
Default value	`Relative humidity`
Program usage name	`moisture_type`
Evaluatable	No

# Trace gas — switching on the output port for measuring the amount of gas impurities

Details

Checking this box enables the G output port to measure the value set by the parameters Measured trace gas specification.

Default value	`true (switched on)`
Program usage name	`measure_trace_gas`
Evaluatable	No

# Measured trace gas specification — method of measuring the amount of gas impurities
Mass fraction | Mole fraction

Details

Sets the measurement method:

Mass fraction - the signal on the G port is equal to the mass fraction of gas impurities.
Mole fraction - The signal on the G port is equal to the molar fraction of gas impurities.

Values	`Mass fraction` \| `Mole fraction`
Default value	`Mass fraction`
Program usage name	`trace_gas_type`
Evaluatable	No

Examples

Modelling of artificial ventilation system