Civil Engineering Reference
In-Depth Information
or damaged, the best approach is to replace the fixture with a modern, efficient unit
with good cleaning capabilities, as well as excellent lumen maintenance characteristics.
Simply changing the lens of a fixture can substantially increase luminous efficiency.
Ballast Efficiency
A ballast transforms line voltage and controls lamp current to match the operating
characteristics of the lamp. The only lamp type that does not require a ballast is the
incandescent lamp. Manufacturers have introduced high-efficiency ballasts that reduce
energy consumption of fluorescent fixtures by as much as 9 percent. These ballasts
have a longer service life than the older design and can provide an overall savings of
as much as 27 percent when used with high-efficiency lamps. This energy savings is
produced with only a small loss of light. Other ballasts will reduce energy consumption
by 20 percent when used with standard lamps, but with a corresponding decrease in
light output. They should be used only where reduced lighting is acceptable.
Maintenance
Lighting systems are poorly maintained at most facilities, with consequent waste of
both money and energy. Lamp output for most lighting systems decreases with use.
Relamping may be cost-effective before lamps burn out. Consideration should be given
to group relamping to reduce maintenance, storage, and energy requirements.
WATER CONSERVATION
The primary focus of water conservation has often been on reducing the impact on
limited raw water supplies, treatment plant capacity, and distribution system capacity.
However, when energy savings are considered, water conservation can take on a new
meaning. With the exception of plants that have gravity-fed distribution systems, water-
demand reduction can correspond to significant savings in energy required for pump-
ing.
Many water utilities have mounted effective water conservation programs to reduce
water consumption at the end use. The greatest source of water waste in most com-
munities is in landscape irrigation. Proper selection of plant materials and irrigation
equipment, as well as good irrigation scheduling, can significantly reduce water use.
Some of the more innovative programs include training for landscape architects and
publishing of evapotranspiration data so irrigation rates can be adjusted. Large users
should be encouraged to conduct a landscape irrigation audit to assess current water
uses and associated costs.
Significant water and energy savings can be achieved by optimization of industrial
processes, consumer education, water recycling, and installation of low-flow pumping
fixtures. Many of these measures reduce sewer flow, which saves pumping energy at
the local wastewater utility.
A water utility could also consider installing meters, if not already in place, for
monitoring domestic accounts. Although a decision to implement metering in a pre-
viously unmetered area may generate disapproval from water customers, the increased
savings may prove to be a financially viable alternative in terms of annual cost savings.
