Climate and built environment

CLIMATE AND BUILT

ENVIRONMENT

MAGESHWARI .A (B.ARCH) II ND YR

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.


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.


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


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.


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.


• 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.

7 . WHAT IS MEANT BY ALTITUDE ..?


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 PRESSUREAtmospheric pressure is the force per unit area exerted on a

surface by the weight of air above that surface in the atmosphere

of Earth


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.


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.


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 ( )


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]

17 . DEFINE RELATIVE HUMIDITY


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


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.


Environmental factors:• Air temperature• Radiant temperature• Air velocity• Humidity

Personal factors:• Clothing Insulation• Metabolic heat

22. WHAT ARE THE FACTORS THAT AFFECT

THERMAL COMFORT


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


• 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]

• Two types of sweat glands can be found in humans: eccrine

glands and apocrine glands. The eccrine sweat glands are


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


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


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 )


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


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


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 combustionIt is measure I J/kg or J/cal




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.

Design

Climate and built environment