modelEnableAndModeControl
Validation model for sidestream HRC enable and mode control
Information
This model validates Buildings.Templates.Plants.Controls.HeatRecoveryChillers.Enable and Buildings.Templates.Plants.Controls.HeatRecoveryChillers.ModeControl. Consequently, it also validates Buildings.Templates.Plants.Controls.HeatRecoveryChillers.Controller, which is composed of the two former blocks.
The validation uses varying ∆T for HW across the HRC condenser and CHW across the HRC evaporator. The model verifies that:
- The HRC is effectively disabled when it is controlled in cooling mode and the leaving HW temperature is high.
- The HRC control mode switches from cooling to heating when the cooling load exceeds the calculated evaporator heat flow rate in heating mode.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | cp_default | 4184 | Default specific heat capacity used to compute required capacity |
| Real | rho_default | 996 | Default fluid density used to compute required capacity |
| Information provided by designer | |||
| Real | COPHea_nominal | 2.8 | Heating COP at design heating conditions |
| Nominal condition | |||
| Real | capHea_nominal | 1E6 | Installed heating capacity |
| Real | THeaWatSup_nominal | 323.15 | Design HW supply temperature |
| Real | THeaWatRet_nominal | 315.15 | Design HW return temperature |
| Real | VHeaWat_flow_nominal | capHea_nominal/abs(THeaWatSup_nominal - THeaWatRet_nominal)/cp_default/rho_default | Design HW volume flow rate |
| Real | capCoo_nominal | capHea_nominal*(1 - 1/COPHea_nominal) | Installed cooling capacity |
| Real | TChiWatSup_nominal | 280.15 | Design CHW supply temperature |
| Real | TChiWatRet_nominal | 285.15 | Design CHW return temperature |
| Real | VChiWat_flow_nominal | capCoo_nominal/abs(TChiWatSup_nominal - TChiWatRet_nominal)/cp_default/rho_default | Design CHW volume flow rate |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Reals.Sources.TimeTable | ratV_flow | Source signal for volume flow rate ratio – Index 1 for HW, 2 for CHW | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant | THeaWatRet | HWRT | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant | TChiWatRet | CHWRT | |
| Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter | VHeaWat_flow | Scale by design flow | |
| Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter | VChiWat_flow | Scale by design flow | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant | THeaWatSup | HWST | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant | TChiWatSup | CHWST | |
| Buildings.Controls.OBC.CDL.Reals.GreaterThreshold | u1Hea | Compute heating plant enable signal | |
| Buildings.Controls.OBC.CDL.Reals.GreaterThreshold | u1Coo | Compute cooling plant enable signal | |
| StagingRotation.LoadAverage | loaChiWat | Available CHW load | |
| Buildings.Templates.Plants.Controls.HeatRecoveryChillers.Enable | ena | ||
| StagingRotation.LoadAverage | loaHeaWat | Available HW load | |
| Components.Controls.StatusEmulator | sta | Emulate HRC status | |
| ModeControl | setMod | Set mode | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Sin | dTHeaWat | HW Delta_T across HRC condenser | |
| Buildings.Controls.OBC.CDL.Reals.Add | THeaWatHrcLvg | HRC leaving HWT | |
| Buildings.Controls.OBC.CDL.Reals.Divide | ratFlo | Flow ratio | |
| Buildings.Controls.OBC.CDL.Reals.Multiply | dTRatFlo | HW Delta-T times flow ratio | |
| Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter | dTChiWat | HRC leaving CHWT | |
| Buildings.Controls.OBC.CDL.Logical.Pre | preMod | Previous mode setting | |
| Buildings.Controls.OBC.CDL.Reals.Max | bou | Bound to avoid division by zero | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant | cst | Constant | |
| Buildings.Controls.OBC.CDL.Reals.Max | bou1 | Bound to avoid unrealistic values | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant | cst1 | Constant | |
| Buildings.Controls.OBC.CDL.Reals.Add | TChiWatHrcLvg | HRC leaving CHWT | |
| Buildings.Controls.OBC.CDL.Conversions.BooleanToReal | staToReal | Convert status to real | |
| Buildings.Controls.OBC.CDL.Reals.Multiply | dTEna | Non-zero HW Delta-T when HRC on | |
| Buildings.Controls.OBC.CDL.Logical.MultiAnd | mulAnd | Make status come and go at low load | |
| Buildings.Controls.OBC.CDL.Reals.GreaterThreshold | greLoaChiWat | True if load greater than minimum before cycling | |
| Buildings.Controls.OBC.CDL.Reals.GreaterThreshold | greLoaHeaWat | True if load greater than minimum before cycling |
Revisions
-
December 10, 2024, by Michael Wetter:
Updated input of hysteresis block and changed threshold to guard against numerical noise.
This is for issue 4074. -
May 31, 2024, by Antoine Gautier:
First implementation.