[EnergyPlus_Support] fixed pulse HVAC size + thermostat w/hysteresis

[Troy Harvey <taharvey@xxxxxxxxxxxxxxxx>]

I am trying the get a EnergyPlus model to model a fixed sized HVAC system with a thermostat having hysteresis.

I typically use EnergyPlus for annualized energy demand, in which the standard purchased air approach is fine — however for my current project, I need to look at realistic control conditions. When you look at a given day with EnergyPlus's HVAC output is an unrealistic variable output supply heat into the zone to meet the instantaneous demand rather than a pulse-modulated fixed output you'd see in a real CAV system . And the zone air temperature is perfectly tracking the set point without any sawtooth pattern caused by thermostat hysteresis.

I have set E+ to a 1 minute simulation interval

The HVAC heat output is like in the red line below, using a compact system with a fixed zone BTU sizing, where what I want is like the blue line:

Any thoughts?

 

thanks,

Troy Harvey
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Principal Engineer
Heliocentric
801-453-9434
taharvey@xxxxxxxxxxxxxxxx