Browse Prior Art Database

Redundant Cooling for a High Availability CPU Enclosure

IP.com Disclosure Number: IPCOM000113478D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 160K

Publishing Venue

IBM

Related People

Hall, D: AUTHOR [+4]

Abstract

Disclosed are two rack-mounted CPU enclosure mechanical packaging schemes, either of which provides redundant cooling required in a high availability processing environment such as on-line transaction processing. The mechanical packaging is specifically related to a Symmetric Multi-Processor Rack project currently in IBM development.

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This is the abbreviated version, containing approximately 52% of the total text.

Redundant Cooling for a High Availability CPU Enclosure

      Disclosed are two rack-mounted CPU enclosure mechanical
packaging schemes, either of which provides redundant cooling
required in a high availability processing environment such as
on-line transaction processing.  The mechanical packaging is
specifically related to a Symmetric Multi-Processor Rack project
currently in IBM development.

      Tube-axial fans are the air-moving devices generally used in
the air cooling designs of electronic boxes such as computer systems
units.  In high performance computer servers and workstations,
adequate cooling is critical to the function and reliability of these
systems.  These systems use multiple fans for adequate cooling.  Due
to limited space, cooling is compartmentalized, i.e., any given card
or component is dependent on one specific fan.  A rotational speed
sense line on each of the fans will automatically bring down the
system in an orderly sequence when a fan failure occurs.  The system
will remain down until it is serviced and the faulty fan is replaced.

      One method commonly used for redundant cooling is to mount
multiple fans in parallel in a plenum.  The plenum air inlets provide
evenly distributed airflow even after one fan fails.  The fans are
sized such that the reduced airflow still provides adequate cooling
for reliable operation.  This method, however, requires considerable
volumetric space for the plenum.  This additional space is not
available in the given enclosure application with its dimensional
constraints (10.5 X 17.3 X 33.1 in., Height X Width X Length).

      The disclosed cooling schemes allow the system to continue
operating after a fan failure.  Components normally cooled by the
failed fan are provided airflow by other fans which are cooling other
components and which are also in series with the failed fan.  The
failed fan can then be serviced at some convenient time.

      In this CPU Enclosure, shown in Figs. 1 and 2, the critical
components to be cooled are on four processor cards and six memory
cards, and sixteen adapter cards.  Since the enclosure is
rack-mounted, airflow inlets and exhaust can only be in the front and
rear.  The three primary cooling fans (C) are in parallel and cool
the processor and memory components (A) by providing evenly
distributed airflow from front to rear.  These three fans exhaust
into the adapter cards (H) providing co...