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COMPONENTS OF CLIMATE
WEATHER
 The weather of a place represents the state of the atmospheric environment over
a brief period of time.
CLIMATE
 Integrated weather condition over several years is generally referred to as climate.
An analysis of the climate of a particular region can help in assessing the seasons or
periods during which a person may experience comfortable or uncomfortable
conditions.
 The information helps a designer to build a house that filters out adverse climatic
effects, while simultaneously allowing those that are beneficial. The built-form and
arrangement of openings of a building can be suitably derived from this analysis
 Climate thus plays a pivotal role in determining the design and construction of a
building.

FACTORS AFFECTING CLIMATE: Both weather and climate are characterized by the certain
variables known as climatic factors. They are as follows:

1. Solar radiation
2. Ambient temperature
3. Air humidity
4. Precipitation
5. Wind
6. Sky condition
7. Vegetation

SOLAR RADIATION

 Solar radiation is the radiant energy received from the sun.

 It is the intensity of sunrays falling per unit time per unit area
and is usually expressed in Watts per square meter (W/m2).
 The radiation incident on a surface varies from moment to
moment depending on its geographic location (latitude and
longitude of the place), orientation, season, time of day and
atmospheric conditions.
 Solar radiation is the most important weather variable that
determines whether a place experiences high
temperatures or is predominantly cold.
 The instruments used for measuring of solar radiation
are the pyranometer and the pyrheliometer. The
duration of sunshine is measured using a sunshine
recorder.
 Thermopile is an electronic device that converts thermal
energy to electrical energy.
 Pyranometer: It measure the total hemispherical solar
radiation

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 Sunshine recorder: Measures the duration in hours of bright sunshine during the course of
the day.

EFFECT ON ORIENTATION EFFECT OF SKY CONDITION

EFFECT OF TIME

AMBIENT TEMPERATURE

 The temperature of air in a shaded (but well ventilated) enclosure is known as the ambient
temperature.
 It is generally expressed in degree Celsius (ºC).
 Temperature at a given site depends on wind as well as local factors such as shading,
presence of water body, sunny condition, etc.

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EFFECT OF SHADING

TEMPERATURE

 Temperature is a physical quantity that expresses the subjective perceptions of hot and cold.
 Temperature is measured with a thermometer, historically calibrated in various temperature
scales and units of measurement.
 The most commonly used scales are the Celsius scale, denoted in °C the Fahrenheit scale
(°F), and the Kelvin scale.

AIR HUMIDITY

 Air humidity, which represents the amount of moisture present in the air.
 High humidity accompanied by high ambient temperature causes a lot of discomfort.
 Measured using Hygrometer

PRECIPITATION

 The definition of precipitation is any form of water - liquid or solid falling from the sky.
 Precipitation includes water in all its forms rain, snow, hail or dew.
 It is usually measured in millimeters (mm) by using a rain gauge.

WIND

 Wind is the movement of air due to a difference in atmospheric pressure.

 Wind speed can be measured by an anemometer and is usually expressed in meters per
second (m/s).
 It is a major design consideration for architects because it affects indoor comfort conditions
by influencing the convective heat exchanges of a building envelope, as well as causing air
infiltration into the building

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SKY CONDITION

 Sky condition generally refers to the extent of cloud cover in the sky or the duration of
sunshine.
 Under clear sky conditions, the intensity of solar radiation increases; whereas it reduces in
monsoon due to cloud cover.

VEGETATION
Plants Used for Climate Control
• For climate control, deciduous shade trees might be used to screen the hot summer sun
or in winter permit the solar radiation to penetrate to the ground, or to the walls and
windows of a building.
• Large shrubs can serve as windbreaks to reduce wind velocities.
• Changes in solar radiation or light levels are also possible with shading.

USE OF PLANTS TO DIRECT SUMMER BREEZES TREES CONTROLS SOLAR RADIATION

• In addition to these factors, a number of natural elements such as hills, valleys,

waterbodies, etc. affect the climate locally.
• Buildings, cities and other man-made features also have an impact on the climate.
TILT OF THE EARTH'S AXIS
 The earth rotates around its own axis,
each rotation making one 24-hour
day.
 The axis of this rotation (the line
joining the North and South Poles) is
tilted to the plane of the elliptical
orbit, at an angle of 66.5° (i.e. a tilt of
23.5° from the normal) and the
direction of this axis is constant.

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 Maximum intensity is received on a plane normal to the direction of radiation. If the axis of
earth were rectangular to the plane of the orbit, it would always be the equatorial regions
which are normal to the direction of solar radiation. Due to the tilted position, however, the
area receiving the maximum intensity moves north and south, between the tropic of Cancer
(latitude 23.5°N.) and the tropic of Capricorn (latitude 23.5°S.). This is the main cause of
seasonal changes.
ROLE OF CLIMATE

 Climate plays a very important role in architectural and building forms. The comparison
of climatic data and the requirements for thermal comfort provides the basis for the
selection of building form and building elements appropriate for the climate so as to create
necessary internal comfort.
 Climate conditions are effective in arrangement of building designs, determination of
requirements, selection of equipment and building method, and accordingly the formation.
Different climate systems generate regional architectural characteristics.
 Planning and forming the building in accordance with the regional climatic data are based
on enabling the building to get minimum heat during the hottest season of the year and lose
minimum heat during the coldest season of the year.
 The required thermal comfort values should be determined, the daily and annual durations
of use of the building should be specified according to the quantity and activity levels of
users of the building. This data should be used in making decisions regarding the position,
direction, form, interior planning and building shell design of the building in urban planning
and applying these decisions.
 East:
The east side of the house will receive direct morning sun but will be shaded in the afternoon by the
shadow of the building itself.
 West:
The west side of the house will be shaded in the morning but fully exposed to the hot afternoon sun.
 South:
The south side of the house is most critical to passive solar design because it receives the most sunlight
throughout the day but never as intensely as the east or west sides.
 North:
The north facing side of the house is almost always in shade.
CLIMATE AND BUILT ENVIRONMENT

 DEFINE THE TERM “CLIMATE “

 Climate is a measure of the average pattern of variation in temperature, humidity, atmospheric
pressure, wind, precipitation, atmospheric particle counts and other meteorological variables in a
given region over long periods of time
 HOW DOES CLIMATE DIFFER FROM WEATHER?
 Climate is different from weather, in that weather only describes the short-term conditions of these
variables in a given region
 DEFINE “WEATHER”
 Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or
stormy, clear or cloudy. Weather, seen from an anthropological perspective, is something all humans
in the world constantly experience through their senses, at least while being outside
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 WHAT ARE THE FACTORS THAT DETERMINE THE CLIMATE OF A PLACE?

 The factors that determine climate of a place are temperature, precipitation, altitude, location,
latitude, tilt of the axis, surface currents, winds, and elevation.
 DEFINE THE TERM “TEMPERATURE”
 A temperature is a numerical measure of hot and cold. Its measurement is by detection of heat
radiation, particle velocity, kinetic energy, or most commonly, by the bulk behaviour of a
thermometric material.
 It may be calibrated in any of various temperature scales, Celsius, Fahrenheit, Kelvin, etc.
 DEFINE THE TERM “PRECIPITATION”
 precipitation is any product of the condensation of atmospheric water vapour that falls under gravity.
 The main forms of precipitation include drizzle, rain, sleet, snow, and hail.
 DEFINE THE TERM “LATITUDE”
 Latitude is the distance of a location from the equator.
 The hottest temperatures on Earth are found near the equator. This is because the sun shines directly
on it for more hours during the year than anywhere else.
 As you move further away from the equator towards the poles, less sun is received during the year
and the temperature become colder.
 WHAT IS MEANT BY ALTITUDE
 Altitude is the height you are above sea level.
 The higher up you are the lower the temperature will be.
 This is because air that is higher up is less dense than it is at lower altitudes and air temperature
depends on its density.
 As a general rule for every 1,000m higher you go the temperature will drop by 6.5 °C.
 DEFINE “WIND”
 Wind is the flow of gases on a large scale.
 On the surface of the Earth, wind consists of the bulk movement of air.
 DEFINE “ELEVATION”
 The elevation of a geographic location is its height above or below a fixed reference point.
 DEFINE ATMOSPHERIC PRESSURE
 Atmospheric pressure is the force per unit area exerted on a surface by the weight of air above that
surface in the atmosphere of Earth
 DEFINE HUMIDITY
 Humidity is the level of water in the air, the more water vapour in the air the higher the humidity.
 If the humidity level exceeds the amount of water air can hold condensation occurs forming dew if
it's warm or frost if it's cold.
 Humidity varies with temperature and is measured in percentage
 WHAT ARE OCEAN CURRENTS...?
 Currents are driven by the prevailing winds passing over the surface of the ocean.
 Therefore, winds blowing from tropical areas bring warm currents and vice versa.
 DEFINE ATMOSPHERIC PRESSURE
 Atmospheric pressure is the force per unit area exerted on a surface by the weight of air above that
surface in the atmosphere of Earth
 DEFINE MEAN SEA LEVEL PRESSURE
 The mean sea level pressure (MSLP) is the atmospheric pressure at sea level or the station pressure
adjusted to sea level assuming that the temperature falls at a lapse rate of 6.5 K per km in the fictive
layer of air between the station and sea level.
 WHAT IS ABSOLUTE HUMIDITY
 Absolute humidity is the mass of the water vapour (), divided by the volume of the air and water
vapour mixture.
 WHAT IS SPECIFIC HUMIDITY

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 Specific humidity (or moisture content) is the ratio of water vapour mass to the air parcel's total (i.e.,
including dry)
 DEFINE RELATIVE HUMIDITY
 The relative humidity of an air-water mixture is defined as the ratio of the partial pressure of water
vapour (H2O) in the mixture to the saturated vapour pressure of water at a given temperature. Thus
the relative humidity of air is a function of both water content and temperature.
 DEFINE THERMAL COMFORT
 Thermal comfort is the condition of mind that expresses satisfaction with the thermal environment
and is assessed by subjective evaluation
 Maintaining this standard of thermal comfort for occupants of buildings or other enclosures is one
of the important goals of HVAC (heating, ventilation, and air conditioning) design engineers.
 WHAT DO YOU MEAN BY CLOTHING INSULATION?
 The amount of thermal insulation worn by a person has a substantial impact on thermal comfort,
because it influences the heat loss and consequently the thermal balance?
 Layers of insulating clothing prevent heat loss and can either help keep a person warm or lead to
overheating.
 Generally, the thicker the garment is, the greater insulating ability
 DEFINE MEAN RADIANT TEMPERATURE
 The radiant temperature is related to the amount of radiant heat transferred from a surface, and it
depends on the material’s ability to absorb or emit heat, or its emissivity
 DEFINE EFFECTIVE TEMPERATURE
 The effective temperature of a body such as a star or planet is the temperature of a black body that
would emit the same total amount of electromagnetic radiation.
 Effective temperature is often used as an estimate of a body's temperature when the body's
emissivity curve is not known.
 WHAT ARE THE FACTORS THAT AFFECT THERMAL COMFORT?
 Environmental factors:
• Air temperature • Radiant temperature • Air velocity • Humidity Personal factors: • Clothing
Insulation • Metabolic heat?
 DEFINE AIR TEMPERATURE?
 This is the temperature of the air surrounding the body. It is usually given in degrees Celsius (°C) or
degrees Fahrenheit (°F).
 EXPLAIN METABOLISM
 metabolism is the set of life-sustaining chemical transformations within the cells of living organisms.
 These enzyme-catalysed reactions allow organisms to grow and reproduce, maintain their structures,
and respond to their environments.
 The word metabolism can also refer to all chemical reactions that occur in living organisms, including
digestion and the transport of substances into and between different cells
 DEFINE ACCLIMATIZATION
 Acclimatization is the process in which an individual organism adjusts to a gradual change in its
environment (such as a change in temperature, humidity, photoperiod, or ph), allowing it to maintain
performance across a range of environmental conditions.
 Acclimatization occurs in a short period of time (days to weeks), and within the organism's lifetime
(compare to adaptation).
 WHAT IS PERSPIRATION
 Perspiration (sweating, transpiration, or diaphoresis) is the production of fluids secreted by the sweat
glands in the skin of mammals.
 WHAT IS PERSPIRATION
 Perspiration (sweating, transpiration, or diaphoresis) is the production of fluids secreted by the sweat
glands in the skin of mammals.
 WHAT DO YOU MEAN BY SOLAR CONSTANT?
 The intensity of radiation reaching the upper surface of the atmosphere is called as solar constant
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 EXPLAIN EARTH’S ROTATION AXIS

 The earth rotates around its own axis at each rotation 24 hours per day
 The axis of rotation is tilted to the plane of vertical orbit at an angle of 66.5° to the normal and the
direction of axis is a constant
 Maximum intensity of radiation is received on a plane normal to the direction of inclination
 WHAT IS A PHOTON
 Each molecule of particle coming out from the sun is called as photon
 WHAT IS “ITCZ “ITCZ – INTER TROPICAL CONVERGANCE ZONE
 The area where the air rises, where the northerly and southerly winds meets, a tropical flaunt is
formed
 This area experiences either calm conditions or only light breezes of irregular directions and is
referred (doldrums)
 WHAT ARE POLAR WINDS?
 The air at the surface moves from the coldest to the slightly warmer regions away from the poles The
air lags behind the rotating earth as it moves from the poles
 The northerly is deflected into north easterly and southerly is deflected into south easterly
 DEFINE HEAT
 Heat is a form of energy appearing as molecular moment in substances or as radiant heat, or a certain
wavelength bond of electromagnetic radiation in space
 It is measured in joules
 WHAT DO YOU MEAN BY SPECIFIC HEAT OF A SUBSTANCE?
 It is the amount of heat energy necessary to cause unit temperature, increase a unit mass of
substance It is measured in J/kg/℃ The higher the specific heat of a substance the more heat will
absorb for a given increase in temperature
 WHAT IS LATENT HEAT
 It is the amount of heat energy absorbed by the unit mass of substance at change of state, without
any change in temperature

 DEFINE ENERGY
 The capacity to do work is called as energy. It is usually expressed in calories
 WHAT IS THERMAL CAPACITY
 Thermal capacity of a body is product of mass and specific heat of the material. It is measured as the
amount of heat required to cause unit temperature increase of the body. Its unit is J/℃
 WHAT IS CALORIFIC VALUE
 Calorific value is the amount of heat released by unit mass of a fuel or food material by its complete
combustion It is measure I J/kg or J/cal
 WHAT IS CONDUCTION
 The transfer of energy between objects that are in physical contact. Thermal conductivity is the
property of a material to conduct heat and evaluated primarily in terms of Fourier's Law for heat
conduction.
 WHAT IS CONVECTION
 The transfer of energy between an object and its environment, due to fluid motion. The average
temperature, is a reference for evaluating properties related to convective heat transfer.
 WHAT IS RADIATION
 The transfer of energy from the movement of charged particles within atoms is converted to
electromagnetic radiation.

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