Climate Controlled Cabinet for Critical Product.
operation of a Climate Controlled Room or Cabinet the cooler's heat exchanger coils (the cold source) are slowly encased in a film of ice. This is caused by the air borne moisture
in the ambient air sublimating on contact with the cold heat exchanger coils of the cooler and forming ice. This ice build-up is slow, progressive and inexorable. It
can; if left unchecked, transform the heat exchanger coils into a useless block of solid ice.
The ice build-up
is heavily dependent on ambient conditions. If the heat exchanger was positioned or
used air drawn from a climatically controlled area (low humidity), this ice
build-up would be totally different from an installation that was expose to near
saturated air conditions. To allow
for these ambient atmospheric variations, the defrost cycle is usually
controlled by time. So during the
commissioning study stages, the requisite time interval between defrost cycles
must be established.
The most common
design methodology for defrosting the heat exchanger coils is simply to
incorporate in the design an electric hot air blower unit mounted adjacent to
the freezer coils and allow the impingement of this hot air to melt off the
The trouble with this
is you are melting off the ice from the outside in; this can be a long and slow
process, during which it is extremely difficult to stop this hot air from
percolating into the cabinet interior and substantially raising its internal
This was the
reason our cabinets were failing. During defrost cycles the top two shelves
in the cabinets were hopelessly out of specification (actual – 14oC
required -25oC). The
answer was to redesign the defrost methodology.
During the defrost cycle we circulated
the hot gas coming from the compressors through the heat exchange. This sudden flow of hot gas quickly
broke the bond between metal parts and the encumbering ice. This bond
being broken the ice dropped down in to the splash tray
This allowed the defrost cycle to be reset to much shorter intervals. This in turn kept the heat exchanger relatively clear from heavy icing conditions and so significantly enhanced it's thermal efficient while enabling the defrost cycle duration to be reset from seventeen minutes (pre-redesign) to less than six minutes (post redesign).
Since there was now no defrost hot air being circulated the impact of this new defrost methodology on the cabinet internal temperature was found to be insignificant. The electrical power consumption for each modified cabinet dropped by 31%.
Combined IQ/OQ/PQ Equipment Protocol (Issue-2). -- $159.00
combination protocol has been produced in response to several hundred
suggestions we received in our - Suggestions
Section. It has been carefully designed to make it the preferred choice for Process and Laboratory stand-alone equipment. It is an interactive, fully detailed, sixty three page protocol that runs to approximately seven thousand words. It is presented in 'MS Word' to
facilitate ease of final editing by the end user. It has become a very
Combined IQ-OQ-PQ Computer Protocol (Issue 3) -- $159.00
Software Validation SOP (Issue-2) -- $22.00
Software Validation Master Plan (issue-2) -- $115.00
Software Validation Risk Assessment (Issue 2) -- $125.00
Software User Requirements Specification. (Issue 2) -- $115.00
Software Validation Plan (Issue 2) -- $89.00
Software Design Qualification. (Issue 2) -- $89.00
Software Installation Qualification. (Issue 2) -- $89.00
Software Operational Qualification. (Issue 2) -- $89.00
Software Performance Qualification. (Issue 2) -- $89.00
Software Validation Package (Issue 1) -- $699.00
Validation Risk Assessment (Issue10.) -- $125.00
This popular Validation Risk Assessment (VRA) has now been edited and enlarged to include Part 11 assessment tables for you to use in classifying which of your predicate records require to be stored in compliance with 21 Part 11, and which do not. It also includes an Excel spreadsheet to allow you to establish a permanent record of all such judgements, as is now mandated by the regulatory authorities.