Newsletter: Climate Controlled Outdoor Cabinets for Communications Systems
Welcome to the July 2008 issue of GL's consulting newsletter. In this issue, we focus on climate controlled outdoor
cabinets that house telecommunications systems.
Climate controlled outdoor equipment cabinets play an important role in insuring reliable and quality communications
links. Outdoor cabinets that house today's modern communications systems are very different from their earlier versions.
Present-day cabinets are home to a number of state-of-the-art electronic systems and components used for public
communications, intelligent transportation systems, CCTV surveillance, and other equipment related to homeland security
for transit and public safety requirements. The electronic systems include computers and servers consisting of
microprocessors, fiber optic devices, Ethernet routers and switches, uninterrupted power supply units, and other
semiconductor components. They are very susceptible to high temperatures and high humidity. Overheating and
condensation would shorten their life expectancies and cause major failures. Hence, they require an environment
controlled for heat and humidity for proper functioning.
Temperatures inside an outdoor cabinet can vary widely depending on the season and the location. GL conducted a
detailed study of the environment inside a typical cabinet housing a server and a few active fiber optic components. The
study showed that temperatures near sensitive systems can easily rise above 130°F in summer months, when the
outside air temperature hovers in the 90s (°F) (as indicated by the red line in Figure 1 below). Using the information
gathered during the study, along with our extensive knowledge and experience, GL's engineers have designed and
specified suitable climate controlled outdoor cabinets for our customers.
Figure 1. Temperatures at various points inside a cabinet without climate control
Two basic technologies are available for cooling an outdoor cabinet, a passive 'heat exchanger', or active
(Freon-compressor type) air conditioning. This is apart from the traditional fan or blowers used in some cases. A passive
heat exchanger consists of a fluid-filled 'heat pipe' assembly. Typically, passive heat exchanger units are only good for very
minor cooling tasks (around 600 BTU or less) with very little heat producing equipment inside the cabinet, and in very
moderate climates. Even with minimal equipment installed in a cabinet, a 600 BTU 'heat exchanger' would not come close
to cooling adequately when outside temperatures reach 80°F or more. Active air conditioning becomes a must for
anything more than that.
Factors to Consider
Whoever said designing a communications cabinet was easy and a low tech job? Designing a modern-day
communications cabinet is complex and requires extensive knowledge and experience. Some factors that go into design
Size and type of communications equipment
Equipment placement inside cabinet
Mounting systems for the equipment
Total estimated power dissipation
Site location requirements
Proper grout sealants and conduits
Protection standards, grounding, etc.
Environment (climate, sun-loading)
Type of thermal and humidity management
Security systems and access
Remote monitoring and control
GL's experts studied the environmental conditions inside the cabinets and leveraged their experience to design and
specify climate controlled outdoor cabinets. Our solution has led to a more controlled environment inside the cabinet. It
has, in turn, insured that our customers' telecommunications links continue to be highly reliable even under adverse
weather conditions. Click here
for more information.
GL Communications Inc. provides technical consulting, and engineering services in wireless, telecom, and IT disciplines.
Customers include telecom carriers, mass transit and public safety systems nationwide. We have designed over 100 wired
and wireless telecom network systems over the past 22 years. GL is also a DBE/MBE firm certified by Maryland's Department
of Transportation (MDOT), Washington Metropolitan Area Transit Authority (WMATA), South Eastern Pennsylvania
Transportation Authority (SEPTA), Massachusetts Bay Transportation Authority (MBTA) and Virginia Department of
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