Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
The "-2" means that the initial guess at the bounds for UA were incorrect. More likely, something else caused the result to fall outside the initial bounds. For cooling towers, the guess at UA is that the final UA will fall between the DesignLoad and 0.0001 * DesignLoad. You can see this methodology in the RegulaFalsi call.
UA0 = 0.0001 * DesTowerLoad; // Assume deltaT = 10000K (limit)
UA1 = DesTowerLoad; // Assume deltaT = 1K
SolveRegulaFalsi( Acc, MaxIte, SolFla, UA, SimpleTowerUAResidual, UA0, UA1, Par );
The model first simulates the tower using UA = 0.0001 * DesignLoad to get the tower capacity. The UA = DesignLoad is used to get a new tower capacity. The answer for these 2 simulations should be under, then over, the actual DesignLoad. If not, a "-2" results.
As I said, it's usually something else that causes this to happen.
If you send your idf file I can loo further or you can send your file to the HelpDesk.
| | 2 | No.2 Revision |
The "-2" means that the initial guess at the bounds for UA were incorrect. More likely, something else caused the result to fall outside the initial bounds. For cooling towers, the guess at UA is that the final UA will fall between the DesignLoad and 0.0001 * DesignLoad. You can see this methodology in the RegulaFalsi call.
UA0 = 0.0001 * DesTowerLoad; // Assume deltaT = 10000K (limit)
UA1 = DesTowerLoad; // Assume deltaT = 1K
SolveRegulaFalsi( Acc, MaxIte, SolFla, UA, SimpleTowerUAResidual, UA0, UA1, Par );
The model first simulates the tower using UA = 0.0001 * DesignLoad to get the tower capacity. The Then UA = DesignLoad is used to get a new tower capacity. The answer for these 2 simulations should be under, then over, the actual DesignLoad. If not, a "-2" results.
As I said, it's usually something else that causes this to happen.
If you send your idf file I can loo look further or you can send your file to the HelpDesk.
| | 3 | No.3 Revision |
The "-2" means that the initial guess at the bounds for UA were incorrect. More likely, something else caused the result to fall outside the initial bounds. For cooling towers, the guess at UA is that the final UA will fall between the DesignLoad and 0.0001 * DesignLoad. You can see this methodology in the RegulaFalsi call.
UA0 = 0.0001 * DesTowerLoad; // Assume deltaT = 10000K (limit)
UA1 = DesTowerLoad; // Assume deltaT = 1K
SolveRegulaFalsi( Acc, MaxIte, SolFla, UA, SimpleTowerUAResidual, UA0, UA1, Par );
The model first simulates the tower using UA = 0.0001 * DesignLoad to get the tower capacity. Then UA = DesignLoad is used to get a new tower capacity. The answer for these 2 simulations should be under, then over, the actual DesignLoad. If not, a "-2" results.
As I said, it's usually something else that causes this to happen.
If you send your idf file I can look further or you can send your file to the HelpDesk.HelpDesk or via email at energyplus-support@gard.com.
| | 4 | No.4 Revision |
The "-2" means that the initial guess at the bounds for UA were incorrect. More likely, something else caused the result to fall outside the initial bounds. For cooling towers, the guess at UA is that the final UA will fall between the DesignLoad and 0.0001 * DesignLoad. You can see this methodology in the RegulaFalsi call.
UA0 = 0.0001 * DesTowerLoad; // Assume deltaT = 10000K (limit)
UA1 = DesTowerLoad; // Assume deltaT = 1K
SolveRegulaFalsi( Acc, MaxIte, SolFla, UA, SimpleTowerUAResidual, UA0, UA1, Par );
The model first simulates the tower using UA = 0.0001 * DesignLoad to get the tower capacity. Then UA = DesignLoad is used to get a new tower capacity. The answer for these 2 simulations should be under, then over, the actual DesignLoad. If not, a "-2" results.
As I said, it's usually something else that causes this to happen.
If you send your idf file I can look further or you can send your file to the HelpDeskHelpDesk or via email at energyplus-support@gard.com.
