1999

1999

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Jan 99
Feb 99
Mar 99
Apr 99
May 99
Jun 99
Jul 99
Aug 99
Sep 99
Oct 99
Nov 99
Dec 99

 

Performance of the GTAC PV System for 1999

This page contains measured performance data for the GTAC PV system for the year 1999.
Click on any month on the left to obtain that month’s data.

  • AC Energy Production [Mwh]

 

Month Measured Predicted*
January 20.7 18.7
February 25.6 22.6
March 33.9 34.0
April 37.3 39.7
May 46.4 46.9
June 37.9 42.9
July 40.6 44.0
August 43.0 42.5
September 35.3 31.7
October 11.2** 32.3
November 0.0** 23.0
December 14.8 18.8

* The "predicted" AC energy production for
each month was found using the computer model PVFORM 3.3, with the TMY providing
metheorological data.

** During October, failure of a cooling fan in the PCU
led to system downtime due to overtemperature shutdowns. The inverter was disabled in
November, and was enabled again on December 3, when a new fan was installed.

  • Mean daylight-hours module temperature [oC]

 

Month Measured Predicted
January 18.5 10.5
February 22.2 12.3
March 24.2 19.3
April 32.5 28.5
May 38.5 33.3
June 38.8 35.5
July 44.0 37.4
August 46.6 38.4
September 39.9 32.2
October 31.9 26.8
November 27.6 18.6
December 19.2 12.0

* The measured mean daylight-hours module temperatures are typically
a few degrees higher than the predicted ones. We believe this is due at least in part to
the roof curvature, which impacts air flow above and beneath the array, and standing
seams, which may impede airflow behind the modules more than expected.

  • Daily average solar energy flux [MWh/m2/day]

 

Month Measured Predicted
January 2.63 3.15
February 3.55 3.43
March 4.47 4.68
April 5.01 5.39
May 6.09 6.31
June 5.16 5.98
July 5.58 5.98
August 5.98 5.76
September 5.13 4.43
October 3.93 4.29
November 3.19 3.11
December 2.70 2.44
  • Average sunlight-to-AC-power efficiency [%]

 

Month Measured*
January 8.11
February 8.24
March 8.22
April 7.92
May 7.83
June 7.79
July 7.55
August 7.38
September 7.59
October 7.57
November N/A**
December 8.11

* This "average" efficiency was found using only the times
during which the system’s DC power was higher than 80 kW. For lower DC powers, sensor
inaccuracies cause the values to be suspect.

** The inverter was disabled during November, due to fan failure.

  • Typical DC voltage range [V]

 

Month Measured
January 360-450
February 360-440
March 350-440
April 310-425
May 330-425
June 330-405
July 320-405
August 325-400
September 325-430
October 350-445
November N/A*
December 380-445

* The inverter was disabled during November, due to fan failure.