blockSetpointController
Calculates the chiller stage status setpoint signal
Information
The sequence is a chiller stage status setpoint controller that outputs the
chiller stage integer index ySta, chiller stage change trigger signal
y and a chiller status vector for the current stage yChi.
It is implemented according to ASHRAE Guideline 36-2021, section 5.20.4.1 - 15.
The controller contains the following subsequences:
- Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.CapacityRequirement to calculate the capacity requirement
- Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Configurator to allow the user to provide the chiller plant configuration parameters such as chiller design and minimal capacities and types. It calculates the design and minimal stage capacities, stage type and stage availability
- Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Status to calculate for instance the next higher and lower available stages
- Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Capacities to calculate design and minimal stage capacities for current and next available higher and lower stage
- Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.PartLoadRatios to calculate operating and staging part load ratios for current and next available higher and lower stage
- Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Up to generate a stage up signal
- Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Down to generate a stage down signal
- Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Change to set the stage based on the initial stage signal and stage up and down signals
- Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.ChillerIndices to generate the chiller index vector for a given stage
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| General › Plant configuration parameters | |||
| Boolean | have_WSE | false | True = plant has a WSE, false = plant does not have WSE |
| Boolean | have_serChi | false | True = series chillers plant; false = parallel chillers plant |
| Boolean | have_senDpChiWatRemWir | true | True = remote DP sensor hardwired to controller |
| Integer | nRemSen | 2 | Total number of remote differential pressure sensors |
| Boolean | anyVsdCen | false | Plant contains at least one variable speed centrifugal chiller |
| General › Chiller configuration parameters | |||
| Integer | nChi | 2 | Number of chillers |
| Real[nChi] | chiDesCap | Design chiller capacities vector | |
| Real[nChi] | chiMinCap | Chiller minimum cycling loads vector | |
| Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Types.ChillersAndStages[nChi] | chiTyp | {Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Types.ChillersAndStages.PositiveDisplacement, Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Types.ChillersAndStages.VariableSpeedCentrifugal} | Chiller type |
| Integer | nSta | 3 | Number of chiller stages, does not include zero stage |
| Integer[nSta,nChi] | staMat | {{1, 0}, {0, 1}, {1, 1}} | Staging matrix with stage as row index and chiller as column index |
| Time parameters › Hold and delay parameters | |||
| Real | avePer | 300 | Time period for the capacity requirement rolling average |
| Real | delStaCha | 900 | Hold period for each stage change |
| Real | parLoaRatDelay | 900 | Enable delay for operating and staging part load ratio condition |
| Real | faiSafTruDelay | 900 | Enable delay for failsafe condition |
| Real | effConTruDelay | 900 | Enable delay for efficiency condition |
| Real | shortTDelay | 600 | Short enable delay for staging from zero to first available stage up |
| Real | longTDelay | 1200 | Long enable delay for staging from zero to first available stage up |
| Conditionals › Staging part load ratio parameters | |||
| Real | posDisMult | 0.8 | Positive displacement chiller type staging multiplier |
| Real | conSpeCenMult | 0.9 | Constant speed centrifugal chiller type staging multiplier |
| Real | anyOutOfScoMult | 0.9 | Outside of G36 recommended staging order chiller type SPLR multiplier |
| Real | varSpeStaMin | 0.45 | Minimum stage up or down part load ratio for variable speed centrifugal stage types |
| Real | varSpeStaMax | 0.9 | Maximum stage up or down part load ratio for variable speed centrifugal stage types |
| Conditionals › Value comparison parameters | |||
| Real | smallTDif | 1 | Offset between the chilled water supply temperature and its setpoint for the long condition |
| Real | largeTDif | 2 | Offset between the chilled water supply temperature and its setpoint for the short condition |
| Real | faiSafTDif | 1 | Offset between the chilled water supply temperature and its setpoint for the failsafe condition |
| Real | dpDif | 2*6895 | Offset between the chilled water pump diferential static pressure and its setpoint |
| Real | TDif | 1 | Offset between the chilled water supply temperature and its setpoint for staging down to WSE only |
| Real | TDifHys | 1 | Hysteresis deadband for temperature |
| Real | faiSafDpDif | 2*6895 | Offset between the chilled water differential pressure and its setpoint |
| Real | dpDifHys | 0.5*6895 | Pressure difference hysteresis deadband |
| Real | effConSigDif | 0.05 | Signal hysteresis deadband |
Connectors
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Up | staUp | Stage up conditions | |
| Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Down | staDow | Stage down conditions | |
| Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.CapacityRequirement | capReq | Capacity requirement | |
| Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.SetPoints.Subsequences.Capacities | cap | Design and minimum capacities for relevant chiller stages |
Revisions
-
April 14, 2020, by Milica Grahovac:
First implementation.