.Buildings.Controls.OBC.RadiantSystems.Cooling.HighMassSupplyTemperature_TSurRelHum

Information

Controller for a radiant cooling system.

The controller tracks the surface temperature set point TSurSet by adjusting the supply water temperature set point TSupSet based on the output signal y of the proportional controller. Both, the surface temperature set point TSurSet and the resulting supply water temperature set point TSupSet are limited by the dew point temperature that is calculated based on the inputs TRoo and phiRoo. The pump is either off or operates at full speed, in which case yPum = 1. The pump control is based on a hysteresis that switches the pump on when the output of the proportional controller y exceeds 0.2, and the pump is commanded off when the output falls below 0.1. See figure below for the control charts.

ASHRAE Standard 55-2004 recommends that the surface temperature of a radiant floor is above 18°C to avoid discomfort for spaces in which people wear typical footwear.

For systems with high thermal mass, this controller should be left configured as a P-controller, which is the default setting. PI-controller likely saturate due to the slow system response.

Revisions

• March 29, 2022, by Michael Wetter:
  First implementation.
  This is for issue 2823.