How to set a deadband so while the zone air temperature is between 22 and 26°C the heating system is off.Am using designbuilder so maybe I can do this through an EMS file

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designbuilderknowledge

asked 2016-10-19 07:16:41 -0500, updated 2016-10-20 07:42:02 -0500

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Are 22C and 26C your heating and cooling setpoints?

pflaumingo (2016-10-19 09:39:21 -0500) edit

I said the ELSEIF doesn't make sense because if the TSTAT turns on the heater when AptTemp < hSP (the ELSE), then you only want it to turn off when AprTemp > hSP+Toffset. I believe your EMS prog will turn off the heater as soon as AptTemp> hSP. I see now the ELSEIF is meant to hold off heating while the space floats back down to hSP. What about when the heater is on while space is moving toward hSP+Toffset? The IF will turn it off at hSP.

rraustad (2016-10-19 11:59:06 -0500) edit

Hi, Thanks for commenting I have no cooling system i just want to maintain a temp. of 22-26 inside the room. Your Help is Appreciated

designbuilderknowledge (2016-10-20 01:58:48 -0500) edit

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The ELSEIF doesn't make sense. If AvailSCH_Overwrite = 0 && something else, SET AvailSCH_Overwrite = 0 ??

IF AptTemp > (hSP), SET AvailSCH_Overwrite = 0,
ELSEIF AvailSCH_Overwrite == 0 && AptTemp >= (hSP) && AptTemp <= (hSP + Toffset), SET AvailSCH_Overwrite = 0,
ELSE, SET AvailSCH_Overwrite = 1, ENDIF

The program should instead do:

IF AvailSCH_Overwrite == 0 && AptTemp < (hSP), SET AvailSCHOverwrite == 1,
ELSEIF AvailSCH_Overwrite == 1 && AptTemp > (hSP+Toffset), SET AvailSCHOverwrite == 0,
ELSE SET AvailSCHOverwrite == NULL;

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rraustad

answered 2016-10-19 10:03:11 -0500, updated 2016-10-19 12:01:14 -0500

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Thank you very much your comment is right but am still getting errors any idea why?

designbuilderknowledge (2016-10-20 02:42:22 -0500) edit

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If this question is related to the linked one than you need first to set the heating setpoint to 26C and an EMS control logic will be similar to the code desribred here

This is the code which should work in your case

Schedule:Constant,Cycle,OnOff,1; ! New schedule object

AvailabilityManager:Scheduled, ! Updated Availability Manager
  Packaged Rooftop Air Conditioner Availability Manager, 
  Cycle;

EnergyManagementSystem:Sensor,
  AptTemp,
  BLOCK1:ZONE1,
  Zone Mean Air Temperature;

! Don't forget to set heating setpoint to 26C
EnergyManagementSystem:Sensor,
  hSP,
  BLOCK1:ZONE1,
  Zone Thermostat Heating Setpoint Temperature;

EnergyManagementSystem:Actuator,
  AvailSCH_Overwrite,
  Cycle,
  Schedule:Constant,
  Schedule Value;

EnergyManagementSystem:ProgramCallingManager,
  Supervision,
  BeginTimestepBeforePredictor,
  HVAC_uncontolledloop_Supervision;

EnergyManagementSystem:Program,
  HVAC_uncontolledloop_Supervision,
  SET Toffset = 4,
  IF AptTemp > (hSP - 0.01), ! -0.01 due to system can maintain the zone temperature very close to the setpoint
  SET AvailSCH_Overwrite = 0,
  ELSEIF AvailSCH_Overwrite == 0 && AptTemp >= (hSP - Toffset),
  SET AvailSCH_Overwrite = 0,
  ELSE,
  SET AvailSCH_Overwrite = 1,
  ENDIF;