.Buildings.Controls.OBC.ASHRAE.G36

Information

This package contains control sequences from ASHRAE Guideline 36 (G36). All sequences are created using blocks from the Buildings.Controls.OBC.CDL library, following the CDL specification.

The G36 library is structured as follows:

Implementation of PID controllers

For the PID controllers, the implementation in Buildings.Controls.OBC.CDL.Reals.PID is used. Hence, the PID controllers are in the standard form

y(t) = k   ( e(t) + 1 ⁄ Ti   ∫ e(s) ds + Td de(t)⁄dt ),

where y(t) is the control signal, e(t) = us(t) - um(t) is the control error, with us(t) being the set point and um(t) being the measured quantity, k is the gain, Ti is the time constant of the integral term and Td is the time constant of the derivative term.

Note that the units of k are the inverse of the units of the control error, while the units of Ti and Td are seconds. As the units of flow rates and pressure can vary between orders of magnitude, for example depening on whether cfm, m3⁄s or m3⁄h are used for flow measurements, the control error is normalized as follows:

Guideline 36 is specific as the where a P or a PI controller should be used. These recommendations are used as the default control configuration. However, all controllers can be configured as P, PI or PID controller. This allows to configure a PI controller as a P controller as part of the tuning process.

References

ASHRAE Guideline 36P, High Performance Sequences of Operation for HVAC systems. Official Release, May 2020.

Contents

NameDescription
AHUsAHU Sequences as defined in guideline G36
GenericGeneric control sequences
TerminalUnitsControl sequences for terminal units
ThermalZonesPackage of sequences for calculating temperature setpoint
VentilationZonesPackage of sequences calculating ventilation airflow
ZoneGroupsPackage of sequences in zone group level
TypesPackage with type definitions for control sequences

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