Environmental Engineering Reference
In-Depth Information
under-floor ventilation systems, are slowly overcoming the problems of
current systems. Under-floor air supply is recommended as an alternative
to ceiling air supply in office buildings to overcome the lack of flexibility
in ceiling systems and to improve comfort conditions [27,28]. The under-
floor system is recommended it due to its capability of reducing energy
consumption due to the operational characteristics of supplied air.
7.3.4.4 Closure
Because energy consumption optimisation is the new trend, new inves-
tigations are needed in the scientific research in order to achieve success.
Actually, energy utilisation mainly depends on optimum utilisation of con-
ditioned air in conditioned spaces. Sets of common terms, definitions and
symbols are essential for all segments from top to bottom. These include
energy needs, technical building systems, auxiliary energy use, recoverable
system losses, primary energy and renewable energy.
7.3.5 Air-Conditioning System Design of Commercial Buildings
In theory, if properly applied, every system can be successful in any build-
ing. However, in practice, such factors as initial and operating costs, space
allocation, architectural design, location and the engineer's evaluation and
experience limit the proper choices for a given building type. Heating and
air-conditioning systems should be simple in design and of proper size
for a given building, should involve generally fairly low maintenance and
low operating costs and should have optimal inherent thermal control as
is economically possible. Such control might include materials with high
thermal properties, insulation and multiple or special glazing and shading
devices.
An example of commercial building application is provided here for librar-
ies and museums. In general, libraries have storage areas, working and office
areas, a main circulation desk, reading rooms, rare topic vaults and small
study rooms. In general, museums have exhibit areas, work areas, back
offices and storage areas. Some larger museums may have souvenir shops,
a restaurant or cafeterias and so forth.
7.3.5.1 Load Characteristics
Many libraries, especially college libraries, operate up to 12 hours per day
and may run the air-conditioning equipment about 4200 hours per year.
Such constant usage requires the selection of heavy duty, long-life equip-
ment that requires little maintenance. Museums are generally open about
8-10 hours per day, 5-7 days per week. The ambient conditions should not
vary in temperature or relative humidity. The conditions should remain con-
stant 24 hours per day, year-round. Cold or hot walls and windows and hot
