Energy Smart Management
Outdoor swimming pools are big
energy consumers. Pool owner/ operators spend billions
of dollars annually to heat the nation's pools. Much
of this energy is often wasted and can be saved with
proper management. Wasting energy also contributes
to our growing air quality problem.
RSPEC! is a national program
that asks you to consider measures to Reduce Swimming
Pool Energy Costs.
Pools lose energy in a variety
of ways, but evaporation is by far the largest source
of energy loss for swimming pools. When compared to
evaporation, all other losses are small.
The reason evaporation has such
an impact is that evaporating water requires tremendous
amounts of energy. It only takes 1 Btu to raise 1 pound
of water 1 degree, but each pound of 80 degree water
that evaporates takes a whopping 1048 Btu's of heat
out of the pool.
The following diagram illustrates
the impact of evaporation on the total energy consumption
of the outdoor pool.
Since evaporation is the major
source of heat loss for swimming pools, to minimize
evaporation, one must cover the pool. Covering your
pool when it's not in use is the single most effective
way of reducing pool heating costs. Savings of 50-70%
are possible.
There are many energy management
improvements that can be implemented with outdoor pools.
Below are three types of pool
covers. Refer to the fact sheet on pool covers for
more detailed information.
Pool covers also provide many
other benefits besides saving energy. They conserve
make-up water by 30-50% and can reduce chemical consumption.
Cleaning time is cut by preventing dirt and other debris
from entering the pool.
 It
is highly recommended that the first step to cutting
pool energy loss be the evaluation of the economics
of using a swimming pool cover.
Covers must be managed properly
for safety. They should always be completely removed
before anyone enters the pool.
One item that can greatly increase
evaporation from outdoor pools is wind blowing over
the pool. A 7 mph wind at the surface of the pool can
increase energy consumption by 300%. Adding trees,
shrubs, fences, or other wind break material can significantly
lower the heat loss from the pool while it's open.
Pool covers are great at stopping
evaporation when the pool is closed, but can't do anything
to cut evaporation when the pool is open.
The windbreak needs to be high
enough and close enough to the pool that it doesn't
create turbulence over the pool and increase evaporation,
but try not to block the sun from shining on the pool.
One of the most cost-effective
uses of solar energy is to heat swimming pools. Swimming
pools require low temperature heat, which is where
solar collectors are most efficient. You can use either
unglazed or glazed collectors to heat an outdoor pool,
however, unglazed collectors are most commonly used
on outdoor pools. If your pool is operated year around
and located in a cold climate region, the unglazed
systems will not provide much heat in the winter, but
may be more cost-effective overall because of their
lower initial cost.
Glazed systems are more expensive,
because they usually have black chrome-plated copper
absorber plates, require the use of a non-freezing
transfer fluid and a heat exchanger to transfer the
solar heat to the swimming pool water.
Unglazed systems are usually
made of a black plastic or rubber material and the
pool water is circulated directly through the collectors.
Neither system requires a storage tank. The pool serves
as the storage tank.
 Solar
pool heating systems can provide up to 100% of your pool heating
needs. They are also much simpler to install than are other forms
of solar systems. The combination of a solar pool heating system
and the use of a cover at night can greatly extend the length
of your swimming season with minimal operating costs.
If you plan to purchase a conventional
pool heating system, shop around for a high efficiency
pool heater. High efficiency gas heating systems are
available with steady state efficiencies as high as
97%. Electric heat pump pool heaters are also available
with coefficients of performance (COPs) in the 6.0-8.0
range when operated in warm weather. A COP of 6.0 is
600% more efficient than an electric resistance heater.
Using properly sized energy-efficient
pumps and motors when replacing older pumps and motors,
or when designing new pools, can significantly lower
the electrical consumption of pool operating costs.
Motors use many times their initial cost in electrical
consumption over their life and can often consume several
times their cost in the first year alone. The energy
savings from an energy efficient motor can pay for
itself in a very short time.
 Replace
inefficient incandescent lamps with high efficiency
compact fluorescents. They consume 1/2 to 1/3 the amount
of electricity and last 10 times as long as standard
incandescent lamps. Replace standard fluorescent ballasts
and lamps with electronic ballasts and T-8 lamps. They
will reduce consumption by 30%.
The initial cost of energy efficient
lighting is more, but the combination of the energy
savings and labor savings on replacement will far offset
that initial cost in most cases where lights are on
for several hours per day or night.
Outdoor areas can be lit with
high intensity discharge (HID) lamps. They offer high
efficiency and high output. Install motion detectors
in areas like shower/dressing areas and rest rooms
or on security lighting. They will not only save energy,
but will startle would-be intruders.
Reduce water heating costs in
the shower area by lowering shower temperatures to
95. It will not only lower energy costs, but will shorten
the amount of time people spend under the shower producing
further savings.
Install low-flow showerheads
and automatic shut-off valves on showers to reduce
water consumption and conserve energy. Insulate the
shower water heater to further reduce water heating
costs.
Consider carefully the temperature
that you keep the pool water. Each degree rise in the
temperature can cost you an additional 10%. The National
Swimming Pool Foundation recommends 78-80 for active
swimming and 82-84 for general use.
It's a myth that it takes more
energy to heat a pool up when you turn the temperature
down than you save by lowering the temperature or by
turning off the heater. Turn the temperature down,
or turn off the heater whenever the pool will not be
used for several days. Experiment to determine how
long it takes to heat it back up. Lowering the temperature
and raising it back up again always saves more energy
than keeping it at a constant temperature.
Keep all the intake grates clear
of foreign debris. Clogged drains require the pump
to work harder.
Don't backwash your filter more
frequently than necessary. Backwashing too frequently
wastes water, while not backwashing wastes energy by
requiring the pump to work harder.
For residential pools, reduce
filtration time to 6 hours/day. If the water doesn't
appear clean, increase the time in half-hour increments
until you get the desired results. You can automate
this by installing a time clock for daily pump operation.
Tune up your pool heater annually.
A properly maintained pool heater is more efficient.
How much could YOU save by making
your pool "Energy-Smart"? The Department of Energy
has developed a software package called Energy Smart
Pools to perform those difficult calculations for you.
You can download the Energy Smart Pools software from
this site. Using the Energy Smart Pools software, you
can obtain a detailed analysis and projected savings
with just a few inputs from you. The best part, there
is no cost to you!
If you know someone else who's
interested in saving money on their pool operation,
email them a link to this article. Reproduction and
distribution of this piece is not restricted, but actually
encouraged. RSPEC! can make a difference
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