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On the Horizon: Reducing Power
Consumption at SeaSonde Locations
15 February, 2010
Why
does the CODAR set industry records only to break them shortly after?
Because innovation is the key to expanding utility! CODAR engineers
are working to lower the entire radar site power requirement by as
much as 40-90% of present needs. In this latest development effort
CODAR engineers are reducing the power requirement to an average
of 150 watts for the SeaSonde radar AND cooling system. This ultra-low
power system is ideally suited for remote areas where renewable power
sources or operation from generators is only viable option. Read
on to learn about this exciting work...
Development
Impetus
When calculating the total power required at any radar site, you need to
factor in the consumption of the radar plus that of any associated infrastructure
at that location. Temperature and humidity control for the electronics
enclosure is the potential biggest power draw at the radar site. In mild
climates, keeping the electronics within optimal temperature ranges can
often be achieved with a simple heat exchange fan that draws only 25 watts
power. In contrast, cooling the electronics in warmer climates or stagnant
air becomes more complicated; simple low-power heat exchangers are not
adequate for the task and in those cases use of a closed-loop air conditioning
system is required. Though power for a SeaSonde radar is only 350-450 watts,
air conditioners can sometimes require up to 1.5 kilowatts of power-- over
4 times that of the SeaSonde itself. This poses a problem when power must
be derived solely from renewable sources (e.g. solar or wind), presenting
logistical challenge and high cost.
Prototype
Class-E transmit amplifier shown here.
Reducing
Power With New Design Features
Highly Efficient Transmit Amplifier
The conventional SeaSonde transmit amplifier efficiency is 30%, which
is standard for Class-AB amplifiers designed for use at HF. CODAR engineers
have developed and will be utilizing a breakthrough design Class-E transmit
amplifier having an TX efficiency over 80%. This not only reduces the
amount of required power input to transmit amplifier but also the amount
of heat generated that would otherwise need dissipation.
Electronics Packaging & Built-In Cooling System
A key consideration to maximizing system efficiency is heat management.
The entire electronics layout is being revamped to optimize heat dissipation
inside the system. The transmit and receive electronics are stripped from
the traditional two 19” electronics chassis and assembled together into
one small package, roughly 0.75m height x 0.5m width x 0.5m depth. This
sealed case is weather resistant and suitable for both indoor/ outdoor
use. A cooling system is built into casing with a temperature sensor inside
electronics allowing for intelligent auto on/off.
System Requirement
With an average draw of 150 watts, the power requirement will vary throughout
normal operations from 130 watts - 200 watts, based on the local temperatures
(and hence internal air cooling requirement). Any power generation system
should be engineered to at least 150 watts under any expected local weather
conditions.
Consult CODAR for additional information.
Wind turbine supplying power to a SeaSonde in Alaska. Image courtesy of
Rachel Potter, University of Alaska, Fairbanks
