2. UNIT I CLIMATE AND HUMAN
COMFORT
Factors that determine climate of a place –
Components of Climate – Climate classifications for
building designers in tropics – Climate
characteristics. Human body heat balance – Human
body
heat loss – Effects of climatic factors on human body
heat loss – Effective temperature – Human
thermal comfort – Use of C.Mahony’s tables.
MAGESHWARI .A (B.ARCH) II ND YR
3. 1 . DEFINE THE TERM “ CLIMATE “
Climate is a measure of the average pattern of variation
in temperature, humidity, atmospheric pressure, wind,
precipitation, atmospheric particle count and
other meteorological variables in a given region over long periods
of time
2 . 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.
MAGESHWARI .A (B.ARCH) II ND YR
4. 3 .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
MAGESHWARI .A (B.ARCH) II ND YR
5. 4. 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.
5. 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
behavior of a thermometric material.
• It may be calibrated in any of various temperature
scales, Celsius, Fahrenheit, Kelvin, etc.
MAGESHWARI .A (B.ARCH) II ND YR
6. 5 . 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,
graupel and hail.
6. 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.
MAGESHWARI .A (B.ARCH) II ND YR
7. 7 . 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.
MAGESHWARI .A (B.ARCH) II ND YR
8. 8 .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.
9 . DEFINE “ ELEVATION”
The elevation of a geographic location is its height above or below a
fixed reference point .
10 . 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
MAGESHWARI .A (B.ARCH) II ND YR
9. 11. 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
12 . 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.
MAGESHWARI .A (B.ARCH) II ND YR
10. 13 .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
14 . 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.
MAGESHWARI .A (B.ARCH) II ND YR
11. 15 . WHAT IS ABSOLUTE HUMIDITY
Absolute humidity is the mass of the water vapor( ) ,
divided by the volume of the air and water vapor mixture( ,
which can be expressed as:
16. WHAT IS SPECIFIC HUMIDITY
Specific humidity (or moisture content) is the ratio of water vapor mass ( ) to the air
parcel's total (i.e., including dry) mass ( )
MAGESHWARI .A (B.ARCH) II ND YR
12. 17 . DEFINE RELATIVE HUMIDITY
The relative humidity of an air-water mixture is defined as the ratio of the partial pressure of
water vapor (H2O) in the mixture to the saturated vapor pressure of water at a
given temperature. Thus the relative humidity of air is a function of both water content and
temperature.
Relative humidity is normally expressed as a percentage and is calculated by using the following
equation:[4]
MAGESHWARI .A (B.ARCH) II ND YR
13. 18 . 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.
• 19 . 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
MAGESHWARI .A (B.ARCH) II ND YR
14. 20 .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
21. 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.
MAGESHWARI .A (B.ARCH) II ND YR
15. 22. WHAT ARE THE FACTORS THAT AFFECT
THERMAL COMFORT
Environmental factors:
• Air temperature
• Radiant temperature
• Air velocity
• Humidity
Personal factors:
• Clothing Insulation
• Metabolic heat
MAGESHWARI .A (B.ARCH) II ND YR
16. 23. 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).
24 . EXPLAIN METABOLISM
• metabolism is the set of life-sustaining chemical
transformations within the cells of livingorganisms.
• These enzyme-catalyzed 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
MAGESHWARI .A (B.ARCH) II ND YR
17. • 25 .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).
• 26 .WHAT IS PERSPIRATION
• Perspiration (sweating, transpiration, or diaphoresis) is the
production of fluids secreted by the sweat glands in the skin
ofmammals.[1]
• MAGESHWARI Two types .A (B.ARCH) of sweat II ND YR
glands can be found in humans: eccrine
glands and apocrine glands. The eccrine sweat glands are
18. 26 .WHAT IS PERSPIRATION
• Perspiration (sweating, transpiration, or diaphoresis) is the
production of fluids secreted by the sweat glands in the skin of
mammals.
• Two types of sweat glands can be found in humans: eccrine
glands and apocrine glands. The eccrine sweat glands are
distributed over much of the body.
27 . WHAT DO YOU MEAN BY SOLAR CONSTANT
The intensity of radiation reaching the upper surface of the
atmosphere is called as solar constant
MAGESHWARI .A (B.ARCH) II ND YR
19. 28.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
29 .STATE COSINE LAW
Cosine law states that the intensity on a tilted surface equals
in normal intensity times the cosine of angle of incidence
MAGESHWARI .A (B.ARCH) II ND YR
20. 30 . WHAT IS A PHOTON
Each molecule of particle coming out from the sun is called as
photon
31 . 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 )
MAGESHWARI .A (B.ARCH) II ND YR
21. 32.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
• 33 . 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
MAGESHWARI .A (B.ARCH) II ND YR
22. 34 .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
35 . 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
MAGESHWARI .A (B.ARCH) II ND YR
23. 36 . DEFINE ENERGY
The capacity to do work is called as energy . It is usually
expressed in calories
37 . WHAT IS THERMAL CAPACITY
Thermal capacity of a body is product o 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/℃
38 .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
MAGESHWARI .A (B.ARCH) II ND YR
26. 39 . 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.
40 . 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.
41 . WHAT IS RADIATION
The transfer of energy from the movement of charged particles
within atoms is converted to electromagnetic radiation.
MAGESHWARI .A (B.ARCH) II ND YR
