.BuildingSystems.Fluid.Sensors.TemperatureTwoPort

Information

This model outputs the temperature of the medium in the flow between its fluid ports. The sensor does not influence the fluid.

Typical use and important parameters

If the parameter tau is non-zero, then its output T converges to the temperature of the incoming fluid using a first order differential equation. Setting tau=0 is not recommend. See BuildingSystems.Fluid.Sensors.UsersGuide for an explanation.

If transferHeat = true, then heat transfer with the ambient is approximated and T converges towards the fixed ambient temperature T_Amb using a first order approximation with a time constant of tauHeaTra when the flow rate is small. Note that no energy is exchanged with the fluid as the sensor does not influence the fluid temperature.

Setting transferHeat = true is useful, for example, if the sensor is used to measure the fluid temperature in a system with on/off control on the mass flow rate. If transferHeat were false, then the sensor output T would remain constant if the mass flow rate is set to zero, and hence the controller may never switch the mass flow rate on again.

In general, applications in which the sensor output is not used to switch the mass flow rate on should set transferHeat=false.

Revisions

• February 21, 2020, by Michael Wetter:
  Changed icon to display its operating state.
  This is for #1294.
• October 23, 2017 by Filip Jorissen:
  Revised implementation of equations when transferHeat=true. See #840.
• January 12, 2016 by Filip Jorissen:
  Removed parameter tauInv since this now exists in BuildingSystems.Fluid.Sensors.BaseClasses.PartialDynamicFlowSensor.
• June 19, 2015 by Michael Wetter:
  Revised model and documentation.
• June 18, 2015 by Filip Jorissen:
  Added option for simulating thermal losses.
• June 3, 2011 by Michael Wetter:
  Revised implementation to add dynamics in such a way that the time constant increases as the mass flow rate tends to zero. This significantly improves the numerics.
• February 26, 2010 by Michael Wetter:
  Set start attribute for temperature output. Prior to this change, the output was 0 at initial time, which caused the plot of the output to use 0 Kelvin as the lower value of the ordinate.
• September 10, 2008, by Michael Wetter:
  First implementation, based on BuildingSystems.Fluid.Sensors.Temperature.