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EnergyPlus Dual Thermostat Set point

asked 2017-03-20 09:11:57 -0500

Albert gravatar image

updated 2017-05-06 08:23:04 -0500

I have a fairly simple question about the Dual thermostat schedules in EnergyPlus simulation.

I am trying to make some changes to the default schedule set points and learn the effects for several months in an year.

I am wondering how EnergyPlus decides which schedule to use? For instance, if I want to run the simulation in month of May, whether the EPlus takes the cooling set point only for the calculation? So my question is whether EPlus takes heating set point for some winter months (Jan-April) and then cooling set points for summer months (May-October) and again the heating set point for November and December? Something like this or is the calculation measures are entirely different?

In other words, if I am doing a simulation for the month of April, which setpoint schedule it takes? Heating, Cooling or takes both and calculates the set point from that?

Thanks in advance and any suggestion would be great.

Thanks Albert Thomas

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answered 2017-03-20 10:10:51 -0500

The cooling and heating set point temperatures are controlled using the Control Type Schedule Name input field. This example shows a heating set point in winter and a cooling set point in summer. In the control type schedule, 1 = heating, 2 = cooling, 3 = the same cooling and heating set point temperature, and 4 = dual set point control (2 temperatures). When the single cooling and/or heating thermostats are used only a single set point temperature is active at any point during the simulation, for example in winter there is only a heating set point temperature and cooling will not occur. Same for cooling.

ZoneControl:Thermostat,
 Zone 2 Thermostat,       !- Name
 EAST ZONE,               !- Zone or ZoneList Name
 Zone Control Type Sched, !- Control Type Schedule Name
 ThermostatSetpoint:SingleHeating,  !- Control 1 Object Type
 Heating Setpoint with SB,!- Control 1 Name
 ThermostatSetpoint:SingleCooling,  !- Control 2 Object Type
 Cooling Setpoint with SB;!- Control 2 Name

Schedule:Compact,
 Zone Control Type Sched, !- Name
 Control Type,            !- Schedule Type Limits Name
 Through: 3/31,           !- Field 1
 For: AllDays,            !- Field 2
 Until: 24:00,1,          !- Field 3
 Through: 9/30,           !- Field 5
 For: AllDays,            !- Field 6
 Until: 24:00,2,          !- Field 7
 Through: 12/31,          !- Field 9
 For: AllDays,            !- Field 10
 Until: 24:00,1;          !- Field 11

ThermostatSetpoint:SingleHeating,
 Heating Setpoint with SB,!- Name
 Heating Setpoints;       !- Setpoint Temperature Schedule Name

ThermostatSetpoint:SingleCooling,
 Cooling Setpoint with SB,!- Name
 Cooling Setpoints;       !- Setpoint Temperature Schedule Name

Schedule:Compact,
 Heating Setpoints,       !- Name
 Temperature,             !- Schedule Type Limits Name
 Through: 12/31,          !- Field 1
 For: AllDays,            !- Field 2
 Until:  7:00,15.0,       !- Field 3
 Until: 17:00,20.0,       !- Field 5
 Until: 24:00,15.0;       !- Field 7

Schedule:Compact,
 Cooling Setpoints,       !- Name
 Temperature,             !- Schedule Type Limits Name
 Through: 12/31,          !- Field 1
 For: AllDays,            !- Field 2
 Until:  7:00,30.0,       !- Field 3
 Until: 17:00,24.0,       !- Field 5
 Until: 24:00,30.0;       !- Field 7

In this next example, there are 2 set point temperatures, one for heating and one for cooling. Remember that control type = 4 means dual set point temperatures. Heating and cooling can occur any time during the year depending on the zone loads and zone temperature with respect to the 2 temperature set points.

ZoneControl:Thermostat,
 Zone 2 Thermostat,       !- Name
 EAST ZONE,               !- Zone or ZoneList Name
 Zone Control Type Sched, !- Control Type Schedule Name
 ThermostatSetpoint:DualSetpoint,  !- Control 1 Object Type
 Dual Setpoint with DB;   !- Control 1 Name

Schedule:Compact,
 Zone Control Type Sched, !- Name
 Control Type,            !- Schedule Type Limits Name
 Through: 12/31,          !- Field 1
 For: AllDays,            !- Field 2
 Until: 24:00,4;          !- Field 3

ThermostatSetpoint:DualSetpoint,
 Dual Setpoint with DB,   !- Name
 Heating Setpoints,       !- Heating Setpoint Temperature Schedule Name
 Cooling Setpoints;       !- Cooling Setpoint Temperature Schedule Name
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Comments

Thank you very much! This is a very detailed answer. So if we want a constant temperature for a particular season, then go with the control type 1 and 2. However, based on your explanations, I think the dual setting ensures more flexibility in terms of the actual zone load calculations.

Albert gravatar imageAlbert ( 2017-03-20 13:18:57 -0500 )edit

Agreed. Just set up dual set point Tstats and make sure the system operates when you think it should.

rraustad gravatar imagerraustad ( 2017-03-21 12:44:23 -0500 )edit

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Asked: 2017-03-20 09:11:57 -0500

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Last updated: Mar 20