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| Desert
Aire thanks you for responding to our ad in Engineered Systems and
seeking out more information about Desert Aire’s Select Aire (SA)
natatorium dehumidifiers. |
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Desert Aire’s SA Dehumidifiers Outperform Economizers
In
the ad you just read, we made five distinct points stating why our SA
systems are superior to pool room economizers. Here’s the basic
information that supports each of our claims.
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1. SAs reclaim maximum energy from return air
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SA in Winter Heat Recovery Mode
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In
the heating mode, warm, moist air travels over the SA’s cold evaporator
coil transferring its energy (sensible and latent) to the refrigerant
system. Add the energy from the heat of compression to this recovered
heat and you now have a highly efficient heat pump adding energy to the
mixed air of the dehumidifier. At typical pool room conditions of 82°
F/50% to 60% RH, an SA dehumidifier in the heat pump / recovery mode,
will achieve:
- EERs approaching 16 to 18
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2. SAs require less electrical power in full-cooling mode
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Impact of Blowers
An SA dehumidifier has one full-sized supply air blower and a smaller code ventilation exhaust air blower.
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The
economizer requires two full-sized blowers that must overcome higher
internal static pressures caused by the dampers, double filtration and
dead-headed mixing air plenum. The high break horsepower requirements
of the economizer’s blower components increase the operational costs of
the system.
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| When
a Select Aire system is compared to an economizer system at similar air
volumes, the blower energy operational costs are significantly
different. The use of two full-size blowers that must operate 24 hours
per day and overcome higher static pressure virtually doubles the
blower operational costs of an economizer system. The following table
summarizes the costs for both systems. |
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| 3. SAs provide precise humidity and temperature control |
Dehumidification
Desert Aire has a complete line of SA dehumidification systems designed
to solve your toughest humidity and moisture problems. Ranging in
sizes from 18 to 60 tons, our SAs systems remove between 55 and 340
Lb/Hr of moisture.
Temperature
For the most accurate temperature control, Desert Aire properly mounts
its temperature sensors in the return duct. This ensures that the SA
system is always monitoring the most current temperature of the space
and thus making any necessary adjustments accordingly.
Controls
Our Direct Digital Controls (DDC) system is a microprocessor-based
controller which provides the confidence and reliability of a dedicated
solid state control system. This controls package controls all
necessary functions to efficiently operate our SA dehumidifiers. It
can also perform basic diagnostic functions. It also offers 32 input
and output connections to allow for complete digital control of the
dehumidifier.
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| 4. SAs achieve higher moisture removal efficiencies (MREs) |
Compressors and MREs
If an economizer uses a semi-hermetic compressor, this will also reduce
the efficiency of the system. When a semi-hermetic compressor is
unloaded, it closes one of the cylinders, but does not stop its
motion. Therefore, the BTU output per kW input will be greatly reduced
and the economizer’s overall moisture removal efficiency (MRE) will be
reduced too. An SA system uses dual scroll compressors which stage off
one compressor. Shutting down one compressor totally removes its power
requirements, therefore maintaining MRE on the remaining compressor.
Evaporator Coils and MREs
Another energy issue arises because an economizer design uses a
full-face evaporator coil versus our SA’s shorter 8-row coil, which
uses a bypass damper. The full-face coil is cheaper to install, but
causes the system to operate at a higher suction temperature to remove
the same amount of moisture. When a refrigerant system runs at a
higher suction pressure, the compressor must work harder and
experiences a reduction in MREs.
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5. SAs have a smaller footprint, thus require less floor space
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extra space required for the mixing box and second full-sized blower,
an economizer requires significantly more floor space than an SA or
other standard dehumidifier. In addition to the actual enclosure, the
economizer requires that ductwork capable of moving the full system air
volume be installed on both sides of the unit, which increases the
needed floor space. Exhaust air and outdoor air dampers can be
installed on the top of SA dehumidifiers which will increase the height
slightly, but this does not require that more valuable floor space be
used. |
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| For
complete details about all of the benefits and advantages that Desert
Aire’s SA systems have over economizers, click the links below to
download PDFs of all of our pertinent literature. |
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Find a Desert Aire Sales Representative Nearest You
If you're interested in locating and contacting your local Desert Aire sales representative, click here.
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International Sales Assistance
If you would like to find a Desert Aire representative and are outside
the United States and Canada, or have any other questions regarding
Desert Aire, please e-mail:
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
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Are You an Engineer?
We
encourage all engineers to become registered users on our website. As
a registered user, you can access additional information such as unit
dimensional sheets to help you size your application. You're also able
to order hard copies of Desert Aire's literature as a registered
engineer.
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