MIL-HDBK-1165
high purity water. This depends on the levels of contaminants
and/or additive chemicals present. Examples include irrigation,
washracks (except final rinse), and paint booths.
b) Recycling. For once-through coolers, if they
cannot be eliminated, they could be converted to recirculating
systems by connecting them to nearby cooling towers. The
existing recycling systems can be improved, by methods mentioned
above, and the circulation cycles could be increased. Exact
savings will depend on your individual set up, however, an
estimation can be made that for a 300-ton cooling tower operating
daily at 60 percent capacity, increasing the water circulation
cycles (before bleed-off) from 2 to 4 can save nearly 1.5 million
gallons (5.7 million liters) per year!
5.4.1.8
Magnets or Electrostatic Field Generators. You may
have heard claims from some manufacturers about the effectiveness
of magnetic or electrostatic systems to settle out contaminant
particles in cooling tower water by altering their charge. These
claims are, to date, experimental, controversial, and unproven.
More investigation is needed before these treatment systems can
be recommended (or disapproved).
5.4.2
Water Heaters
5.4.2.1
Conventional and Water-Efficient. Although water
heaters are common in residential houses and offices, they also
supply hot water for industrial processes and thus will be
discussed here.
Water heater designs vary throughout the world.
Whereas the "tankless" water heater (discussed below) is common
in Europe, water heaters in the U.S. and Canada are generally the
familiar large central tank type. They are either fueled by
electricity or natural gas, and have a thermostat, properly
called an "aquastat", which activates resistance heating coils
inside the tank (electric) or the gas burner (natural gas) when
the water temperature drops below the setpoint. The newer water
heaters on the market are geared toward being very energy
efficient in comparison to older models. Conservation of water
in these new tanks occurs as a result of these energy efficient
features. For example, new water heaters allow better control of
the temperature of the outgoing water that reduces the amount of
water consumed. You can improve and maintain the water and
energy efficiency of your water heaters by implementing the
suggestions given below, as appropriate for your installation. A
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