DIRINT Model

This routine determines direct normal irradiance using the DIRINT modification of the DISC model.

Inputs

 

Outputs

DIRINT Outputs

Algorithm

1.) Compute KT´.

DIRINT Algo28
2.) Generate ∆KT´.

DIRINT Algo29
Where KT,next´ is the next time series value of KT´ and K ´T is the previous time series value.

 

3.) Create KT´ bins.

 

4.) Create θZ bins.

DIRINT Algo31

 

5.) Set perceptible water bin, Wbin, to 5, as this adjustment is currently not implemented in PlantPredict.

 

6.) Create ∆KT´ bins.

DIRINT Algo32

 

7.) Perform 4-D lookup of DIRINT coefficients using KT´bin, θZ bins, ∆ KT´ bins, and Wbin to get DIRINTcoeff.

DIRINT Algo D Lookup Table
 

8.) Calculate DIRINT direct normal irradiance.

DIRINT Algo33

Reference

Perez, R., P. Ineichen, E. Maxwell, R. Seals and A. Zelenka, Dynamic Global-to-Direct Irradiance Conversion Models. ASHRAE Transactions-Research Series (1992), pp. 354-369.

Maxwell, E. L., A Quasi-Physical Model for Converting Hourly Global Horizontal to Direct Normal Insolation. Technical Report No. SERI/TR-215-3087, Golden, CO: Solar Energy Research Institute, 1987.