2. HUMAN THERMAL COMFORT
Human thermal comfort refers to the state of mind in
which a person feels neither too hot nor too cold, but
rather experiences a pleasant and balanced thermal
environment.
• A cold sensation will be pleasing when the body is
overheated, but unpleasant when the core is already
cold.
• Thus, sensation from any particular part of the skin
will depend on time, location and clothing, as well as
the temperature of the surroundings.
3. FACTORS THAT CONTRIBUTE TO HUMAN
THERMAL COMFORT
01
02
03
04
05
06
CLOTHING INSULATION
HUMIDITY
AIR SPEED
AIR TEMPERATURE
RADIANT TEMPERATURE
METABOLIC RATE
4. CLOTHING
INSULATION
HUMIDITY
• The type and amount of clothing worn affect how the body loses
or retains heat.
• The choice of clothing insulation depends on the environmental
conditions and the wearer's activity level. For instance, if you're in
a cold outdoor environment, you might wear clothing with higher
insulation to retain body heat. On the other hand, if you're in a
warm indoor environment, you'd want lighter clothing with lower
insulation to allow your body to dissipate heat more effectively.
Humidity affects how the body perceives temperature.
Higher humidity can make the air feel warmer, while
lower humidity can make it feel cooler.
CLOTHING INSULATION
HUMIDITY
5. The ambient air temperature is a significant factor.
Generally, a temperature range of 20-23°C (68-73°F) is
considered comfortable for most people when wearing
typical indoor clothing.
Air circulation, such as through fans or natural ventilation,
can help regulate perceived temperature and moisture
on the skin.
AIR SPEED
AIR TEMPERATURE
6. RADIANT
TEMPERATURE
The temperature of surrounding surfaces (like
walls and floors) can impact how people feel.
Cold surfaces can make a room feel colder, even
if the air temperature is comfortable.
METABOLIC
RATE
A person's level of physical activity and
metabolic rate influence their heat production.
RADIANT TEMPERATURE
METABOLIC RATE
7. HOW TO ACHIEVE THERMAL COMFORT USING
PASSIVE DESIGN TECHNIQUES?
There are few passive design techniques which can be incorporated
in the building during designing in order to achieve the thermal
comfort inside the building:
1. Design as per Climate
2. Orientation of the building
3. Sustainable building design
4. Natural Ventilation
5. Natural lighting
6. Shading
7. Materials
8. Landscaping
9. Water body
10. Use of Renewable sources of energy
8. DESIGN AS PER CLIMATE
• India as a country has different climatic zones, such
as cold climate in northern part, hot and dry in
western areas then hot and humid in southern part of
the country.
• So, the designing has to be different as per the
different climatic zones to achieve thermal comfort
inside the building.
• Design parameters for different climatic zones are
also different.
• This is one of the first thing that designer should
keep in mind before starting designing any project.
9. ORIENTATION OF THE BUILDING
• Orientation of the building plays a major role in
providing building with passive thermal comfort.
• The placement depends upon the four directions:
East, West, North and South.
• The building can be oriented in such a way to take
advantage of solar gain to reduce heat load or to
protect unwanted solar gain to maintain comfort
inside the building.
• The orientation of the building can vary as per the
climate.
10. SUSTAINABLE BUILDING DESIGN
• It is important to think for sustainable building
designs which contribute towards thermal
comfort.
• There are several techniques that can be
incorporated such as:
i. for hot climate courtyard planning, skylights,
louvers, cooling towers and
ii. for cold climate solarium, insulation, light
shelves etc.
• By incorporating these passive techniques the
use of active techniques becomes lesser.
11. NATURAL VENTILATION
• The natural ventilation is the technique which utilizes
air as a medium to make a building energy efficient.
• When using natural ventilation as a passive design
strategy, it is important to consider how air will move
throughout the space.
• The orientation of the openings such as doors and
windows plays a major role to achieve thermal
comfort through natural ventilation.
• It is recommended to place windows opposite to
each other or at different levels, so the circulation of
air results better in achieving comfort.
12. NATURAL LIGHTING
• Sun is the source of natural lighting and it
contributes in saving lots of energy.
• Using artificial lighting can add up to the extra heat
which can lead to uncomfortable environment inside
the space.
• The natural lighting is beneficial in many ways, it cut
down negative spaces, create positive environment
among the users and also help in killing the germs.
• But one thing which needs to be taken care as a
designer is the glare because it can create
discomfort for the occupants.
13. SHADINGS
• Unprotected glass windows is often the greatest
source of heat gain and shadings are the solution to
this problem.
• Shading reduces summer temperature, improves
comfort and save energy.
• Effective shading can block up to 80% of the heat.
• There are several types of shading such as vertical
and horizontal shading, eaves, window awnings,
shutter, pergolas and planters etc.
• The calculation for shading designing is as per angle
of the sun, location, climate and orientation of the
site.
• If calculated by keeping all these parameters in mind
the shading can maximize the thermal comfort inside
the space.
14. MATERIALS
• The materials used in the building plays a vital role in
heat gain inside the building and so, it is very
important to understand the usage of materials.
• The use of local/vernacular available materials can
cut down on energy consumption and ultimately in
cost of the building.
• For example- For hot climate minimum glass use is
recommended so as to minimize the heat gain inside
the building.
• But in case of cold climate the use of glass is
maximized to gain more heat in order to achieve
comfort inside the space.
15. LANDSCAPING
• Landscaping inside and outside the building space
can create a lot of difference and helps in
maintaining the thermal comfort.
• There can be several ways to design landscaping for
indoors and outdoors.
• For example- For hot climate the series of evergreen
trees can be planned on the south or west direction
in order to block the direct harsh sunlight entering
the building.
• For indoors the landscaping can be designed in
courtyard or other spaces.
16. WATER BODY
• Planning a water body indoors and outdoors of the
building space can help in creating a micro-climate.
• This micro-climate can help in achieving thermal
comfort which will contribute to energy efficiency of
the building.
• For hot and dry climate it may create a cooling effect
because it absorbs the heat and help in lowering the
temperature of the space.