Page 243 - Alternative Energy Systems in Building Design

LEED 219

As mentioned in Chap. 3, when generating electric energy by burning fossil fuels,
power losses resulting from turbines and transformation and transmission losses,
which in some instances can be as high as 70 percent, also contribute significantly to
generating considerable amounts of air and water pollutants. Since solar power is pro-
duced on the site, there are no power-generation and distribution losses. Consequently,
power-production efficiency compared with conventional electric power plants is
significantly higher. In other words, the efficiency of solar power compared with
conventional electric energy generated and transmitted hundreds or thousand
miles is significantly greater, and it is cost-effective and less expensive when taking
collateral expenses associated with state and federal pollution-mitigation expenses
into consideration.

Solar power engineering design measures Special electrical engineering
design measures undertaken to maximize the solar power production output include the
following:

■ To maximize the available solar platform area, the PV modules were design to
cover the rooftops in a flat-array formation. Losses resulting from the optimal tilt
angle (about 11 percent) were significantly compensated by a gain of more than
40 percent in surface area, which resulted in deployment of a much larger number
of PV modules and less expensive support-system platforms.
■ PV array-string grouping was modularized to within 6-kW blocks. Each block of the
array has been assigned to a dedicated 6-kW highly efficient inverter. The distributed
configuration of arrays was intended to minimize shading effect of a group PV
system, which guarantees maximum independent performance by each array group.
■ The inverters used are classified as the most efficient by the CEC (CEC-approved
component list) and are designed for direct connection to the electrical grid.
■ All ac solar power feeder conduits and cables were somewhat oversized to mini-
mize voltage-drop losses.
■ In addition to direct power production, roof-mounted solar panels provide significant
roof shading, which extends the roof covering life by approximately 25 percent; they
also keep the roofs cool and therefore increase the R value of insulation, thus reducing
the air-conditioning system operation, which accounts for a notable amount of energy
reduction.
■ An advanced computerized telemetry and monitoring system is designed to monitor
and display real-time power-output parameters from each building. Instantaneous
display of power output in kilowatthours, system power efficiency, cumulated power-
output statistics, barometric pressure, outdoor temperature, humidity, and many other
vital operational parameters are displayed on a number of screens on the supervisory
console.

A specially designed solar power display located in the Water and Life Museum
provides an interactive display on a large flat plasma monitor whereby visitors to the
museum are allowed to interact and request information regarding the solar power
cogeneration system.