Project Name
Project Number
TEMF
Statement of Work
UFC 4-214-02, 24 Jul 03
velocity of 2.8 m/s to preclude moisture carryover. Heating and cooling equipment in humid
areas shall be designed to meet the load determined by computer calculation. However, a larger
fan may be required to meet minimum air flow requirements than would be anticipated based on
the computer load. Equipment may be oversized by no more than 15 percent of the computer
generated sensible load.
10-3.1
Load calculations. The one percent wet bulb temperature, from the approved
weather data source of 10-1.2 above, will be used in calculating the latent cooling load and for
equipment sizing. In addition to calculating the cooling load at maximum design temperature,
cooling load calculations or thermal simulations should also be made at maximum dew point
temperatures or for low temperature, high humidity conditions to determine the greatest
dehumidification load that may be encountered. Latent heat gain due to water vapor flow
through roofs and walls will be included in the cooling load analysis when the ambient design
dew point exceeds the room design dew point by more than 11.1 degrees C.
10-3.2
Chilled water systems. The cooling capacity of 350 kW and over systems will be
divided between two or more chillers to ensure reliability and constant chilled water supply
without temperature fluctuations, to prevent short cycling, and to minimize hot gas by-pass. The
combined capacity of the chillers will not exceed the total requirement, including diversity. The
selection of the number of chillers will be based on the analysis of part load operating hours for
extended periods of low load conditions.
10-3.3
Packaged units. Packaged unitary units with multiple reciprocating compressors (not
to exceed eight) will be used for systems between 123 kW and 750 kW. Each compressor will
have separate, independent, refrigerant circuits and cycles to provide multiple steps of capacity
control. Two compressors may be combined into one independent refrigerant circuit. For
systems up to 123 kW, single compressors with a minimum of three-step capacity unloading
may be used.
10-3.4
Outside air. Where the outside air requirements are a significant part of the cooling
load, the use of desiccant cooling, enthalpy wheels and similar devices for conditioning the
outside air and transferring latent and sensible heat to the exhaust air shall be considered. If
appropriately sized, these units can eliminate or minimize the latent load in the conditioned
space saving significant energy and greatly increasing the comfort level.
10-4
MECHANICAL SYSTEMS. Each building core area shall be provided with a
[central] heating [and air conditioning] system[s]. Systems shall be designed, installed,
balanced, and adjusted to distribute heat [and cooling] to all habitable rooms, as well as
bathrooms, in proportion to the calculated load requirements of these spaces. Each repair bay
shall be provided with a heating [and ventilating] system. Each warehouse bay shall be provided
with a heating [and ventilating] system. [The District in close coordination with the installation
shall determine the allowable system types and fuel options to be used. Also coordinate unit
locations with installation facilities engineering personnel (DPW). Select a system type below or
provide a description of other acceptable systems as an additional subparagraph. All
reasonably equivalent fuel options within a range of 10 percent based on life cycle cost analysis
shall be allowed. The Design District may assist the Installation in preparation of the fuel life
cycle cost comparison.] Additional consideration in the technical evaluation will be given to
systems utilizing energy efficient equipment, additional space in the mechanical room, and other
features which contribute to ease of system operation and maintenance. Additional
consideration will also be given to designs which provide measures to increase energy
conservation or occupant comfort such as division of each building into more than one
SOW-86
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