[EnergyPlus_Support] energyplus PV

["Griffith, Brent" <brent_griffith@xxxxxxxx>]

David, 

 

Hello, I hope this finds you doing well.  

 

A couple of "issues" have come up with your PV implementation in
EnergyPlus that I am hoping you might be able to spend of bit time to
help us straighten out.  

 

The first issue is an easy one.  The Energy+.idd data dictionary
includes default values and I think maybe the following are mixed up.

 

GENERATOR:PV:EQUIVALENT ONE-DIODE,

< snipped >>

 

   N15, \field Temperature Coef. of Isc

         \default -0.079

         \type real

         \units A/K

   N16, \field Temperature Coef. of Voc

         \default 0.02

         \type real

         \units V/K

 

I think the values may be switched.  Could it be that the 0.02 value is
the default temp coef and -0.079 value is for the voltage coef.  This
seems more in line with the I/O ref and various catalog data I have
seen.

 

The second issue seems to be a tricky numerical problem that is causing
the model to crash.  It seems to depend on the number of cells in series
and if this gets too high the model has numerical problems.  For
example, the input below crashes E+, but if I reduce the number of cells
in series (within the module) from 112 to 104 it runs.  Maybe modern PV
modules have more cells and higher voltages and pack more power than the
model's numerics can handle?  Have you seeing anything similar going on
with TRNSYS implementation?  

 

Any help would be greatly appreciated.

 

Brent Griffith

EnergyPlus Development Team

 

 

  GENERATOR:PV:Equivalent One-Diode,

        Sanyo HIT-HIP-190BA3,      !- Array Name

        MonoCrystalline,         !- Array Type

        SawtoothTiltSurface,     !- Surface Name

        1,                       !- Cell Temperature Mode
{dimensionless}

        112,                      !- Number of Cells in Series
{dimensionless}

        1,                       !- Number of Modules in Parallel
{dimensionless}

        262,                       !- Number of Modules in Series
{dimensionless}

        1.18,                    !- Active Area {m2}

        0.9,                     !- tau-alpha Product {dimensionless}

        1.12,                    !- Semiconductor Bandgap {eV}

        1000000,                 !- Shunt Resistance {ohms}

        3.75,                    !- Short Circuit Current {A}

        67.5,                    !- Open Circuit Voltage {V}

        25.0,                    !- Reference Temperature {C}

        1000.0,                  !- Reference Insolation {W/m2}

        3.47,                    !- Module Current at Maximum Power {A}

        54.8,                      !- Module Voltage at Maximum Power
{V}

        0.00086,                 !- Temperature Coef. of Isc {A/K}

        -0.169,                   !- Temperature Coef. of Voc {V/K}

        20,                      !- NOCT Test Ambient Temperature {C}

        44.2,                      !- NOCT Test Cell Temperature {C}

        800.0,                   !- NOCT Test Insolation {W/m2}

        30.0,                    !- Module Heat Loss Coefficient
{W/m2-K}

        50000;                   !- Total Heat Capacity {J/m2-K} 

 



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