Page 119 - Alternative Energy Systems in Building Design

SOLAR POWER SYSTEM CONFIGURATIONS 95

■ Solar plane-of-array irradiance
■ Ambient temperature
■ Wind speed

Calculated parameters displayed include

■ AC power output
■ Sunlight conversion efficiency to ac power
■ Sunlight conversion efficiency to dc power
■ Inverter dc-to-ac power-conversion efficiency
■ Avoided pollutant emissions of CO , SO , and NO gases
2
x
x
This information and calculated parameters are displayed on monitors and updated
once every second. The data also are averaged every 15 minutes and stored in a locally
accessible database. The software also includes a “Virtual Array Tour” that allows
observers to analyze the components of the PV array and monitoring system. The soft-
ware also provides an optional portal Web capability whereby the displayed data can
be monitored from a remote distance over the Internet.
The monitoring and display software also can be customized to incorporate descriptive
text, photographs, schematic diagrams, and user-specific data. Some of the graphing
capabilities of the system include

■ Average plots of irradiance, ambient temperature, and module temperature that are
updated every 15 minutes and averaged over one day
■ Daily values or totals of daily energy production, peak daily power, peak daily
module temperature, and peak daily irradiance plotted over the specified month
■ Monthly values of energy production, incident solar irradiance, and avoided emis-
sions of CO , NO , and SO plotted over the specified year
x
x
2
General description of the monitoring system The central monitoring system
reflects the actual configuration of the Water and Life Museum Project located in
Hemet, California, and designed by me. This state-of-the-art monitoring system
provides a real-time interactive display for education and understanding of photo-
voltaic and the solar electric installation, as well as monitoring the solar electric system
for maintenance and troubleshooting purposes.
The system is made up of wireless inverter data transmitters, a weather station, a
data-storage computer, and a data-display computer with a 26-in LCD screen. In the
Water and Life Museum Project configuration, the inverters, which are connected in
parallel, output data to wireless transmitters located in close proximity. Wireless trans-
mitters throughout the site transmit data to a single central receiver located in a cen-
tral data-gathering and monitoring center.
The received data are stored and analyzed using the sophisticated software in
computer-based supervisory systems that also serve as a data-maintenance interface
for the solar power system. A weather station also transmits weather-related information