Equipment Rack Active Cooling System
Background: Highly sophisticated electronic systems are routinely deployed to remote areas of
the world in support of military, civilian, and humanitarian missions. Remote cell relay towers,
local internet gateways for remote schools, civilian and military surveillance systems, and remote
hospitals deployed to disaster areas are all examples of such systems. Some of these systems may
be deployed in vehicles or small aircraft. Many such systems are “rack mounted” electronics
that end up being deployed to extremely hot and humid locations. Since modern electronic
systems generate a great deal of waste heat, this heat load must be dissipated in order to maintain
functionality of the electronics. As more and faster electronic components and processors are
added to various electronic communication, control, or processing systems, this heat load can
become so substantial that the underlying electronics cease functioning or fail outright. Small
scale thermoelectric cooling technology (Peltier, etc.) have shown applicability to cool individual
electronic components. However; thermoelectrics have a diminishing return as the heat load
increases over 2000W or more. The purpose of this Capstone design project is to develop an
innovative “all purpose” ~3 ft3 enclosure that can dissipate 2 KW of continuously generated
electronics heat from an enclosure, while simultaneously protecting the contents from water
condensation and any particulate contamination during the cooling process.
A New Design Concept: This Senior Capstone Design project is to develop an “active cooling
system” to continuously dissipate a 2000W heat source inside a small (~3ft³) enclosure while
maintaining the internal temperature between 15°C and 45°C. The enclosure must be isolated
from the outside, and thus cannot exchange air with the outside environment. Any water that is
precipitated out of the interior of the enclosure during cooling must be evacuated or sequestered
in a way that won’t allow it to wet or damage anything on the inside of the enclosure. The
apparatus (if any) inside the enclosure must evenly cool the air within in the enclosure and not be
directly (physically) connected to any of the heat sources inside. Any supporting apparatus on
the outside of the enclosure must be minimized in size, preferably having a footprint smaller than
the enclosure itself. The supporting apparatus may be mounted on the enclosure, or may be
separately installed as far as 20ft from the enclosure itself. The active cooling system must draw
its power from a source separate from the equipment enclosure.
Since active cooling necessarily requires a power source, it is important that the system be as
efficient as possible in transporting heat from the enclosure to the outside environment. It will
also require some type of medium for removing the heat from the enclosure. The medium type is
flexible, but should be of a type that can be easily and safely transported with no hazardous
materials or chemical compounds requiring special personal protection equipment or handling.
The medium and any connections should be between 5-20ft from the enclosure. This is to
simulate a common installation of an active cooling system in a ground or airborne vehicle.
To be usable in austere environments, the system should be able to operate off different power
sources. As a minimum, the cooling system should be powerable from a common 110VAC (for
testing), a 12 VDC automotive system, and a 24VDC military vehicle standard. If possible,
power interface options should be provided to allow the system to be powered from a common
vehicle alternator/inverter, solar panel, or motive generator like a small wind turbine. Any other
innovative ideas to power and control the system are highly desirable.
Skills Needed for This Work: (1) Basic understanding of thermodynamics. (2) Control system
theory for closed loop temperature control. (3) Mechanical and Electrical design skills for
mounting and constructing components. (4) Test planning and testing skills to ensure capability
and durability of a finished design.
Sponsor: Air Force Research Laboratory – Sensors Directorate, WPAFB, OH
Mr. Ben Bosma, AFRL/RYZ, ben.bosma@mtsi-va.com, (937) 478-6705