modelStageProcesses

Information

This example validates Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.Staging.Subsequences.StageProcesses. It demonstrates the process of enabling (enaPro) and disabling (disPro) tower cells.

It shows the processes for three different cooling tower configurations.

• The towers have the isolation valves only at the cell inlet, with the valve end switches status feedback: endPro and disPro.
• The towers have the isolation valves only at the cell inlet, without the valve end switches status feedback: endPro1 and disPro1.
• The towers have the isolation valves at the cell inlet and outlet, with the valve end switches status feedback: endPro2 and disPro2.

Following processes are being validated:

• For enabling process in instance enaPro,
  • Initially, all four cells are disabled, the fully open end switches are false, and the fully closed end switches are true.
  • At 380 seconds, the input uChaCel[2] and uChaCel[3] are true, indicating that the status of cell 2 and 3 should be changed. Thus, the isolation valve 2 and 3 are commanded on (y1IsoVal[2] and y1IsoVal[3] become true); the fully closed end switch of valve 2 and 3 become false (u1InlIsoValClo[2] and u1InlIsoValClo[3] become false); all the fully open end switch are still false.
  • After 90 seconds at 470 seconds, the fully open end switch of valve 2 and 3 become true (u1InlIsoValOpe[2] and u1InlIsoValOpe[3] become true). Thus, the cell 2 and 3 are commanded on (yTowSta[2] and yTowSta[3] change to true).
• For disabling process in instance disPro,
  • Initially, all four cells are enabled, the fully open end switches are true, and the fully closed end switches are false.
  • At 380 seconds, the input uChaCel[2] and uChaCel[3] are true, indicating that the status of cell 2 and 3 should be changed. Thus, the cell 2 and 3 are commanded off (yTowSta[2] and yTowSta[3] change to false) and the isolation valve 2 and 3 are commanded off (y1IsoVal[2] and y1IsoVal[3] become false); the fully open end switch of valve 2 and 3 become false (u1InlIsoValOpe[2] and u1InlIsoValOpe[3] become false); all the fully closed end switch are still false.
  • After 90 seconds at 470 seconds, the fully closed end switch of valve 2 and 3 become true (u1InlIsoValClo[2] and u1InlIsoValClo[3] become true).
• For enabling process in instance enaPro1,
  • Initially, all four cells are disabled.
  • At 380 seconds, the input uChaCel[2] and uChaCel[3] are true, indicating that the status of cell 2 and 3 should be changed. Thus, the isolation valve 2 and 3 are commanded on (y1IsoVal[2] and y1IsoVal[3] become true).
  • After the needed time of operating isolation valves (90 seconds) at 470 seconds, the valve 2 and 3 are considered as fully open. Thus, the cell 2 and 3 are commanded on (yTowSta[2] and yTowSta[3] change to true).
• For disabling process in instance disPro1,
  • Initially, all four cells are enabled.
  • At 380 seconds, the input uChaCel[2] and uChaCel[3] are true, indicating that the status of cell 2 and 3 should be changed. Thus, the isolation valve 2 and 3 are commanded off (y1IsoVal[2] and y1IsoVal[3] become false), and the cell 2 and 3 are commanded off (yTowSta[2] and yTowSta[3] change to false).
• For enabling process in instance enaPro2,
  • Initially, all four cells are disabled, the fully open end switches are false, and the fully closed end switches are true.
  • At 380 seconds, the input uChaCel[2] and uChaCel[3] are true, indicating that the status of cell 2 and 3 should be changed. Thus, the isolation valve 2 and 3 are commanded on (y1IsoVal[2] and y1IsoVal[3] become true); the fully closed end switch of valve 2 and 3 become false (u1InlIsoValClo[2], u1InlIsoValClo[3], u1OutIsoValClo[2], u1OutIsoValClo[3] become false); all the fully open end switch are still false.
  • After 90 seconds at 470 seconds, the fully open end switch of outlet valve 2 and 3 become true (u1OutIsoValOpe[2] and u1OutIsoValOpe[3] become true), but the fully open end switch of inlet valve 2 and 3 are still false. Thus, the cell 2 and 3 are still commanded off (yTowSta[2] and yTowSta[3] are false).
  • After another 30 seconds at 500 seconds, the fully open end switch of inlet valve 2 and 3 also become true (u1InlIsoValOpe[2] and u1InlIsoValOpe[3] become true). Thus, the cell 2 and 3 can become commanded on (yTowSta[2] and yTowSta[3] are true).
• For disabling process in instance disPro2,
  • Initially, all four cells are enabled, the fully open end switches are true, and the fully closed end switches are false.
  • At 380 seconds, the input uChaCel[2] and uChaCel[3] are true, indicating that the status of cell 2 and 3 should be changed. Thus, the isolation valve 2 and 3 are commanded off (y1IsoVal[2] and y1IsoVal[3] become false), and the cell 2 and 3 should be commanded off (yTowSta[2] and yTowSta[3] become false); the fully open end switch of valve 2 and 3 become false (u1InlIsoValOpe[2], u1InlIsoValOpe[3], u1OutIsoValOpe[2], u1OutIsoValOpe[3] become false); all the fully closed end switch are still false.
  • After 90 seconds at 470 seconds, the fully closed end switch of outlet valve 2 and 3 become true (u1OutIsoValClo[2] and u1OutIsoValClo[3] become true), and after another 30 seconds at 500 seconds, the fully closed end switch of inlet valve 2 and 3 also become true (u1InlIsoValClo[2] and u1InlIsoValClo[3] become true).

Components

Revisions

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