TM
5-858-7
CHAPTER 3
WASTE-HEAT REJECTION
that of the medium, such as a chilled-water heat
31. Design requirements.
sink in warm rock, there will be appreciable but
a. Preattack. Reject all waste heat to the atmos-
declining heat transfer at the interface as a tem-
phere during the preattack time frame. The design
perature gradient is established in the rock. The
of these open rejection systems is similar to those
heat-transfer rate is influenced by the temperature
found in conventional facilities.
differential and the medium properties. Many vari-
b. Transattack/postattack. Design the trans-
ables influence the relative importance of this heat
attack/postattack waste-heat-rejection system to
source; methods for obtaining quantitative esti-
include no fewer than the following capabilities:
mates of the source are given in TM 5855-4.
--Accommodate the peak waste-heat generation.
c. Personnel related. Personnel-dependent heat
--Accommodate the cumulative wast-heat gen-
sources become increasingly important as popula-
eration.
tion increases and will be the principal heat load for
--Provide acceptable preattack availability.
those facilities that are primarily personnel shel-
-- P r o v i d e acceptable endurance availabil-
ters. Table 31 gives metabolic values correspond-
ity/reliability.
ing to various activity levels for personnel,
--Accommodate preattack exercising.
including a breakdown of sensible and latent (dehu-
(1) Choose the effective degree of atmospheric
midification) heat rates, which can be used for
isolation of the transattack/postattack waste-heat
estimating total heat loads for design of facility
rejection system. In an open system, the heat sink
cooling and dehumidification systems. In applying
is the atmosphere; in a closed system the heat sink
these heat rates, use the personnel activity profiles
is generally a closed (underground) coolant-filled
to determine the total heat load. The allowances
cavity. In general, the more severe the survivabil-
for heat from personnel-dependent electrical power
ity requirement, the more effective the closed sys-
loads may be subject to substantial revision on the
tem (fig. 2l).
basis of specific facility design criteria, but are in-
(2) After identifying the primary sources of
cluded in the interest of completeness.
wast eheat, design the transattack/postattack re-
(1) The sensible heat shown for lighting, air
jection system to fit the level of hardness specified
conditioning, and miscellaneous is intended to cov-
for the facility:
er only that fraction of electrical power required
Open
for personnel needs in occupied facilities. It does
Nominally Hardened (tens of psi
I
not include the associated waste heat or additional
Facilities
overpressure)
power to operate the heat-rejection systems. All
Moderately Hard-
(hundreds of psi)
other values are based on average, adult-male
ened Facilities
metabolism.
Sup-hard Facilities
(thousands [and
(2) The heats of carbonate formation with pos-
greater] of psi)
sible reactants for carbon dioxide absorption can
closed
vary between limits of about 850 and 1800 Btu per
pound of carbon dioxide gas converted to the car-
32. Waste-heat sources.
bonate form; but the more probable reactants and
a. General. Estimating heat loads for the design
processes have reaction heats in the range of 1000
of cooling systems in hardened facilities differs
to 1100 Btu per pound of carbon dioxide. Carbon
dioxide absorption will produce about 15 percent of
only in minor details from heat-load estimation for
more conventional facilities. For hardened facili-
total personnel-dependent heat.
ties, eliminate atmospheric air heat and humidity
d. Power generation and consumption. Power
for design consideration. Consider three heat
supply systems are the primary waste-heat source
sources: heat from geological media, heat from per-
for facilities other than personnel shelters. Except
sonnel, and heat from power generation and con-
for electrical power removed from a facility via
sumption. Include a reasonably accurate evaluation
communications or power cables, the total electri-
of the influence of metabolic heat and the heat of
cal power consumed by the facility will reappear as
carbon dioxide absorption reactions.
waste heat. Consequently, estimate the power-
b. Geological heat. When an underground open-
system-dependent waste heat as the total energy
ing is maintained at a temperature different from
input to the power-generation system, minus any
3-1
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