Download - Building Services- Ventilation
CONTENTS
•Introduction
•Function of natural ventilation
•Supply of fresh air
•Stack due to thermal force
•Convective cooling
•Wind simulators
•Physiology coding
•Air movement through building & around
the building
•Factors affecting indoor air flow &
Around building
•Wind shadow
INTRODUCTION
Climate means a region with a certain condition of temperature, dryness,
wind, light, etc..
It is rather an integration in time of physical states of atmospheric
environment, characteristics of geographical location.
Weather is the momentary state of atmospheric environment at a certain
location .
Climate can be called the integration of time of weather condition.
Climate has 4 major elements:-
EARTH – soil
WATER – humidity
FIRE – sun and temperature
AIR – wind
Climatology is all about the study of these elements
ARCHITECTURAL CLIMATOLOGY
Architecture is all about ART and TECHNOLOGY.
It includes public services, water supply and drainage, air
conditioning, ventilation, lighting, etc.
it is the basic science a designer is concerned about.
It involves majorly on:-
climatic elements how they are behaving on us how to be
benefited by these climatic elements how to protect ourselves from
the adverse effect of climatic elements
The major steps in architectural climatology are:-
climatology-study of climatic elements
biology-study of human comfort level with respect to
climatology
technology-creating of built environment architecture
-the combination of the above and the final product
Ventilation requirements fordifferent workplaces are varied because of
different indoor activities and building designs. The basic methods for
control of airborne contaminants are:
• elimination or control of sources
• fresh air supply of contaminants
• proper air distribution
• air filtration (purification)
• removal of contaminated air
Factors needed to be taken into account in designing the ventilation
requirement include:
• the nature of the operations or activities
• the toxicity and rate of generation of hazardous substances
• the degree of expected occupancy
• the design of the premises.
Function of natural ventilation
VENTILATION
Ventilation is the movement of air within a building and
between the building and the outdoors.
Control of ventilation is most subtle yet important concerns in
building design.
Supply of fresh air
•Ventilation is a process by which air is removed from and supplied to
premises simultaneously.
•To supply fresh air to meet the respiratory needs of the occupants.
•To remove airborne contaminants such as dusts, mists, gases, vapour
tobacco smoke, body odors and bacteria which may pose health hazards or
nuisance to the occupants.
•To maintain the temperature and humidity within an acceptable range that
is appropriate to the activities on the premises.
Stack due to thermal force
•All practical steps have been taken by means of
collectors, scrubbers, or process changes to reduce the
contaminant discharge rates to of reducing emission rates.
•Wind blowing past a stack aspirates air or flue gas out of
the stack. During wind gusts, there are like surges in
outflow from the stack.
•Stacks must be designed and located for satisfactory
cooperation during all wind conditions.
•Wind flow around stacks creates negative zones, eddies,
and vortices in the same manner as around buildings.
Convective cooling
"Convection is the transfer of heat energy by the movement of matter."
There are a few points in that short statement that aren't quite right but it is
adequate for most situations.
Convection is probably the form of heat transfer that we are most familiar
with. We heat our houses with convection (using 'radiators'), we heat our
food in convicting saucepans and fan ovens and we lose most of our excess
body heat through convection. Convection may be familiar, unfortunately it
is also fiendishly complicated
Air movement through building &
around
the buildingIN BUILDING DESIGN there are many basic criteria that are of
doubtful ancestry. Nevertheless, they seem to be firmly embedded in the
minds of the architectural, engineering, and construction fraternity. Lack
of understanding of air flow around buildings and of wind and rain
conditions seems to be the basis for some of this folklore . For example,
many texts stress the need for locating, buildings and their air inlets and
outlets to take advantage of the prevailing winds. Stack caps and
ventilation inlets and outlets are frequently designed for nearly vertical
rain
Factors affecting indoor air flow &
Around building
Natural ventilation is the process of supplying and
removing air through an indoor space without using mechanical
systems. It refers to the flow of external air to an indoor space as a
result of pressure or temperature differences. There are two types of
natural ventilation occurring in buildings: wind driven
ventilation and buoyancy-driven ventilation. While wind is the main
mechanism of wind driven ventilation, buoyancy-driven ventilation
occurs as a result of the directional buoyancy force that results from
temperature differences between the interior and exterior
(1) window openings,
(2) atria and courtyards,
(3) wing walls,
(4) chimney cowls/exhaust cowls,
(5) wind towers,
(6) wind catchers and
(7) wind floor — air inlet system.
(8) solar chimneys and
(9) underground ventilation ducts
Factors affecting indoor air flow &
Around building