Page 229 - Solar Power in Building Design The Engineer's Complete Design Resource

WATER AND LIFE MUSEUM, HEMET, CALIFORNIA 199

of the solar power systems cost for general maintenance, the net energy saving over the
life span of the system could be about $13 million.

Air pollution prevention When generating electric power by brining fossil fuel, the
resulting carbon dioxide production emitted into the atmosphere per kilowatt of electric
energy ranges from 0.8 pounds for natural gas to 2.2 pounds for coal. The variation is
dependent upon the type of fossil fuel such as natural gas, crude oil, or coal used.
In view of the preceding, the pollution abatement measure resulting from the use of
the solar power, at the Museum of Water and Life over the life span of 25 years, is esti-
mated to be 28 million pounds, which will be prevented from polluting the atmosphere.
As mentioned in Chapter 4, when generating electric energy by use of fossil fuels,
power losses resulting from turbines, transformation, and transmission, which in some
instances amount to as high as 70 percent, also contribute significantly toward gener-
ating considerable amounts of air and water pollutants.
Since solar power is produced on the site, it totally eliminates power generation and
distribution losses; consequently, power production efficiency compared to conven-
tional electric power plants is significantly higher. In other words, the cost of solar
power compared to conventional electric energy, which is often generated hundreds or
thousands of miles away and then transmitted, is significantly more efficient, cost
effective, and less expensive when taking collateral expenses associated with state and
federal pollution mitigation expenses into account. Figure 7.10 depicts Water and Life
Museum building-integrated (BIPV) solar power system.

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

■ In order to maximize the available solar platform area, the PV modules were
designed to cover the rooftops in a flat array formation. Losses resulting from the
optimum tilt angle (about 11 percent) were significantly compensated for by a gain
of more than 40 percent of surface area, which resulted in deployment of a much
larger number of PV modules and less expensive support system platforms.
■ Photovoltaic array string groupings were modularized to within 6-kW blocks. Each
array block was assigned to a dedicated 6-kW highly efficient inverter. The distrib-
uted configuration of the arrays was intended to minimize the shading effect of a
group of PV systems, which guarantees maximum independent performance by
each array group.
■ The inverters used are classified as the most efficient by the California Energy
Commission (CEC-approved component list) and are designed for direct connec-
tion 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-mount solar panels provide significant
roof shading, which extends the roof covering life by approximately 25 percent;
they also keep the roofs cool, which increases the “R” insulation value. This in turn