.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_maxPer 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.