Page 120 - Alternative Energy Systems in Building Design

96 SOLAR POWER SYSTEM PHYSICS AND TECHNOLOGIES

to the central computer. The stored data are analyzed and forwarded to a display com-
puter that is used for data presentation and also stores information, such as video,
sound, pictures, and text file data.

Displayed information A standard display usually incorporates a looping back-
ground of pictures from the site, graphic overlays of the power generation in watts and
watthours for each building, and the environmental impact of the solar generating
system. The display also shows current meteorologic conditions. Displayed data in
general should include the following combination of items:
■ Project location (on globe coordinates—zoom in and out)
■ Current and historical weather conditions
■ Current positions of the sun and moon, with the date and time
■ Power generation from the total system and/or the individual solar power arrays
■ Historical power generation
■ Solar system environmental impact
■ Looping background solar system photos and video
■ Educational PowerPoint presentations
■ Installed solar electric power overview
■ Display of renewable-energy system environmental impact statistics

The display should also be programmed to periodically show additional information
related to the building’s energy management or the schedule of maintenance relevant
to the project.
Transmitted data from the weather monitoring station should include air temperature,
solar cell temperature, wind speed, wind direction, and sun intensity measured using a
pyrometer. Inverter monitoring data must incorporate a watthour transducer that will
measure voltage (dc and ac), current (dc and ac), power (dc and ac), ac frequency, watthour
accumulation, and inverter error codes and operation.
The central supervising system must be configured with adequate CPU processing
power and storage capacity to permit future software and hardware upgrading. The
operating system preferably should be based on Windows XP or an equivalent system
operating software platform.
Data communication system hardware must be such that it allows a switch-selectable
RS-232/422/485 communication transmission protocol and has software-selectable
data-transmission speeds. The system also must be capable of frequency hopping from
902 to 928 MHz on the FM bandwidth and be capable of providing transparent multi-
point drops.

Animated video and interactive programming requirements A graphic
program builder must be capable of animated video and interactive programming and
have an interactive animation display feature for customizing the measurements listed
earlier. The system also must be capable of displaying various customizable chart
attributes, such as labels, trace colors and thicknesses, axis scale, limits, and ticks. The
interactive display monitor preferably should have a 30- to 42-in LCD or LED flat
monitor and a 17- to 24-in touch-screen display system.