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 MIL-HDBK-1012/1
This is usually accomplished through use of a "corridor/plenum" concept where
the transmitters are placed in parallel rows facing each other within a long
wing like structure. Partitions between the transmitters and a false ceiling
above separate the operators workspace (corridor) that is air conditioned from
the ventilated plenum behind the transmitters.
For proper operation this system requires :
a) That the incoming outside air to the plenum be tempered
(warmed) by some of the waste heat being exhausted so as to stay above the
highest dewpoint of the outside air to prevent condensation on the inside of
the front face of the transmitter. Ninety degrees F (32 degrees C) is 5
degrees F above the highest dewpoint worldwide as listed in MIL-STD-210.
b) That the conditioned corridor temperature also be maintained at
a value no less than 5 degrees F below the outside air dewpoint to prevent
condensation on the inside of the front face of the transmitter. Eighty
degrees F (27 degrees C) and 50
10 percent relative humidity meets this
requirement and shall be used.
c) That the incoming ventilating air be properly filtered.
d) That a draft hood be placed over the transmitter to collect the
hot exhaust air so that spillover into the room will not occur. This allows a
lower supply air temperature to be maintained (untempered outside air
temperature plus 5 degrees F only) and less air to be moved (smaller or fewer
fans).
e) That a proper control system he utilized to vary the tempering
air to suit a wide range of ambient conditions. Such a system is described in
Figure 4-4 of NAVELEX 0101,102. This will include thermostats, dampers,
damper motors, hoods, filters etc.
8.3.2.2
Heat Exchange. Heat exchange is a system of extracting the heat at
the transmitter exhaust port by latent change of a refrigerant in an
evaporator and transporting the heat via the refrigerant gas to outside
condensers where the heat is released and from where the liquid refrigerant
runs back to the evaporator. This system was developed by NAVFACENGCOM
Chesapeake Division (CHESDIV) and is described in U.S. Patent Office as
statutory invention registration number H8 dated 7 Jan 86 (see Figure 12).
Performance of the system is dependent upon the differential between the
transmitter exhaust temperature (200 degrees F or more) and the outside
ambient temperature (100 degrees F or less). In most locations at least 80
percent of the waste heat will be removed so that it is reasonable to remove
the remaining heat by air conditioning which will also provide humidity
control. Salient features of this (the recommended) system are:
a) A completely conditioned environment for both the equipment and
the operators is provided.
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