modelCoupled

Validation sequence of controlling tower fan speed based on condenser water return temperature control for close coupled plant

Information

This example validates Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.FanSpeed.ReturnWaterTemperature.Subsequences.Coupled.

It shows tower fan speed control for a plant with 2 chillers. The chiller 2 becomes proven on after 360 seconds, and the chiller 1 becomes proven on after 720 seconds. It shows the following processes:

  • Before 360 seconds, no chiller is proven. Thus, the tow speed setpoint is 0.
  • After 360 seconds, chiller 2 becomes proven on and the condenser water pump speed becomes greater than 0. When the pump speed becomes greater than the threshold and shows the pump is proven on at around 444 seconds, the PID controller is retriggered and the output starts from the minimum. However, before the condenser pump is proven on, the tow fan speed setpoint is 0.
  • From around 444 seconds to 720 seconds, the tow fan speed setpoint is the minimum of uMaxTowSpeSet[2], plrTowMaxSpe, and the tower speed from the loop mapping.
  • After 720 seconds, when the chiller 1 also becomes proven on, the tow fan speed setpoint is the minimum of uMaxTowSpeSet[1], uMaxTowSpeSet[2], plrTowMaxSpe, and the tower speed from the loop mapping.

Components

TypeNameDefaultDescription
Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.FanSpeed.ReturnWaterTemperature.Subsequences.CoupledcouTowSpeTower fan speed control based on the condenser water return temperature control for close coupled plants
Buildings.Controls.OBC.CDL.Reals.Sources.SinconRetCondenser water return temperature
Buildings.Controls.OBC.CDL.Reals.Sources.Rampram1Ramp
Buildings.Controls.OBC.CDL.Reals.Addadd2Add real inputs
Buildings.Controls.OBC.CDL.Reals.Sources.ConstantconRetSetCondenser water return temperature setpoint
Buildings.Controls.OBC.CDL.Reals.Sources.RamptowMaxSpeMaximum tower speed specified by head pressure control loop
Buildings.Controls.OBC.CDL.Reals.Sources.RamptowMaxSpe1Maximum tower speed specified by head pressure control loop
Buildings.Controls.OBC.CDL.Reals.Sources.RampplrTowMaxSpeMaximum tower speed reset based on the partial load
Buildings.Controls.OBC.CDL.Logical.Sources.PulsechiSta1Chiller one enabling status
Buildings.Controls.OBC.CDL.Logical.Not[2]not1Logical not
Buildings.Controls.OBC.CDL.Reals.Sources.Constant[2]zerConstant zero
Buildings.Controls.OBC.CDL.Reals.Switch[2]swiLogical switch
Buildings.Controls.OBC.CDL.Logical.Sources.PulsechiSta2Chiller one enabling status
Buildings.Controls.OBC.CDL.Logical.Sources.Pulse[2]conWatPumCondenser water pump status
Buildings.Controls.OBC.CDL.Logical.Not[2]not2Logical not

Revisions

  • August 12, 2019, by Jianjun Hu:
    First implementation.