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# EnergyPlus Dual Thermostat Set point

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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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

more

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.

( 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.

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