.Buildings.Controls.OBC.ASHRAE.G36.AHUs.MultiZone.VAV.SetPoints.SupplyTemperature .Buildings.Controls.OBC.ASHRAE.G36.AHUs.MultiZone.VAV.SetPoints.SupplyTemperatureBlock that outputs the supply air temperature setpoint and the coil valve control inputs for VAV system with multiple zones, implemented according to Section 5.16.2 of the ASHRAE Guideline G36, May 2020.
The control loop is enabled when the supply air fan u1SupFan is proven on,
and disabled and the output set to deadband (no heating, minimum economizer) otherwise.
The supply air temperature setpoint is computed as follows.
TSupCoo_min, TSupCoo_max,
TOut_min, TOut_max
Per Section 3.1.4.1, the setpoints are design information.
TSupCoo_min should be set no lower than the design coil leaving air
temperature to prevent excessive chilled water temperature reset requests.
TSupCoo_max is typically 18 °C (65 °F) in mild and dry climates
and 16 °C (60 °F) or lower in humid climates. It should not typically be
greater than 18 °C (65 °F).
TOut_min=16°C,
TOut_max=21°C) used to reset the occupied mode TSupSet
was chosen to maximize economizer hours. It may be preferable to use a lower
range of outdoor air temperature (e.g. TOut_min=13°C,
TOut_max=18°C) to minimize fan energy.
uOpeMod=1, uOpeMod=2)
The TSupSet shall be reset from TSupCoo_min when the outdoor
air temperature is TOut_max and above, proportionally up to
maximum supply temperature when the outdoor air temperature is TOut_min and
below. The maximum supply temperature shall be reset using trim and respond logic between
TSupCoo_min and TSupCoo_max. Parameters suggested for the
trim and respond logic are shown in the table below. They require adjustment
during the commissioning and tuning phase.
| Variable | Value | Definition |
|---|---|---|
| Device | AHU Supply Fan | Associated device |
| SP0 | iniSet | Initial setpoint |
| SPmin | TSupCoo_min | Minimum setpoint |
| SPmax | TSupCoo_max | Maximum setpoint |
| Td | delTim | Delay timer |
| T | samplePeriod | Time step |
| I | numIgnReq | Number of ignored requests |
| R | uZonTemResReq | Number of requests |
| SPtrim | triAmo | Trim amount |
| SPres | resAmo | Respond amount |
| SPres_max | maxRes | Maximum response per time interval |
uOpeMod=3)
Supply air temperature setpoint TSupSet shall be TSupCoo_min.
uOpeMod=4, uOpeMod=5)
Supply air temperature setpoint TSupSet shall be TSupWarUpSetBac.