Climate-responsive Building Design in North-East India Manoj Kumar Singh1, Sadhan Mahapatra2, S. K. Atreya1

1. Climate-responsive Building Design in North-East India
Manoj Kumar Singh1
, Sadhan Mahapatra2
, S. K. Atreya1
1
Instrument Design and Development Centre, IIT Delhi, New Delhi 110016, India
2
Department of Energy, Tezpur University, Tezpur 784028, Assam, India
Abstract
Energy, environment and architecture are closely related, the more is the energy consumption the worse
is the environmental degradation. With rapid economic growth and improvement in people’s living
standard, the building sector will continue to be the key energy end user. Hence energy conservation
becomes a necessity rather than an option in both commercial and residential buildings and hence it
becomes desirable to design climate responsive buildings by incorporating appropriate solar passive
features. Climate responsive building design is a concept that integrates the micro-climate and
architecture with human thermal comfort conditions. This concept takes into account the solar passive
techniques, micro-climatic conditions and thermal comfort conditions that improve the building
artificial energy efficiency. This fact is well supported by various studies on vernacular architecture as
well as on modern architecture throughout the world. Thermal comfort not only makes the occupants
comfortable but also decides the energy consumption in the building and thus its sustainability.
Throughout the world, from ancient times people have used solar passive techniques that have evolved
through generations. These structures got attention for detailed study among the researchers at present
times. Different researchers had done extensive study on thermal performance of vernacular buildings in
the different parts of the world. However, vernacular architecture of North-Eastern India which
perfectly represents the principle of climate-oriented architecture still lacks experimental validation and
quantitative analysis.
A field study has been carried out to evaluate the thermal comfort perception of the occupants in
naturally ventilated buildings at different bioclimatic zones of North-East India. The survey was
performed in naturally ventilated buildings during the winter, pre-summer season in 2008. There were
220 occupants from 75 vernacular buildings who participated in this study and 200 questionnaire
responses were collected. The data collected include temperature, humidity and lighting level, as well as
results from questionnaires on the occupant’s sensations of thermal comfort. We came across some
interesting findings related to bioclimatism, socio-economic status, cultural setup and sustainability in
this vernacular architecture. We also found different solar passive features available in most of these
houses related to temperature control and promotion of natural ventilation. These houses are constructed
using locally available building materials. Since these materials have low embodied energy and are from
the same climatic zone. Henceforth, they fit into the local environment perfectly and represent a unique
example towards achieving sustainability.
1. Introduction
Energy and architecture form a natural marriage if indoor comfort and respect for environment are
secured. Although energy conservation is an important issue in present days but human thermal comfort
is the primary concern in case of buildings. US energy information administration illustrates that
buildings are responsible for almost 48% of total energy consumption and responsible for substantial
amount of green house gas emissions [1]. Henceforth, it becomes necessity rather than an option for
energy conservation and carbon emission reduction to design built environment considering the local
environment and socio-cultural setup and to make the system more sustainable. It is commonly agreed
within the thermal comfort research community that combination of built environment and individual
thermal comfort expectation creates acceptable thermal environmental conditions for the occupants
within the space [2]. Built environment and comforts standards are increasing with the economic
development and consequently increasing the energy demands. However the term ‘comfort’ itself is
very difficult to define precisely [3]. It is evident from different study that the local climate influences
1
Corresponding author : mksinghtu@gmail.com
13

2. the resident’s behavioral adaptations to the thermal environment [4]. The level of thermal comfort
greatly affects the human’s physical as well as psychological health. In building design the weather
condition or the climatic parameters i.e. air temperature, relative humidity, solar radiation, rainfall
(precipitation), wind speed and direction etc plays an important role. This fact is well supported by
various studies on vernacular architecture as well as modern architecture throughout the world. Out of
the various factors that affect architectural design, climate control is of prime importance as it involves
maintaining comfortable conditions inside the building. If this objective is disregarded discomfort will
prevail, resulting in lower productivity and increase the psychological stress. Simultaneously, the energy
cost of maintaining comfort conditions will rise. Hence it is desirable to design climate responsive
buildings by incorporating appropriate solar passive features.
Buildings based on local climate provide uniqueness, sense of belonging, social and cultural identity [5,
6]. We carried out thermal comfort field survey at representative location across the three different
bioclimatic zones in naturally ventilated buildings during the winter and pre-summer season in 2008.
During our field survey it is found that comfort is a combination of number of various factors and
thermal environment is one of them. There were 220 occupants from 75 vernacular buildings who
participated in the study and 200 questionnaire responses were collected. The questionnaire generally
acquires the response of resident’s consciousness on different aspects of comfort on a sensation scale.
We have also collected temperature, relative humidity and day lighting level data, both inside and
outside of the houses. We tried to generate qualitative and quantitative information about the comfort
status of the residents of vernacular buildings of North-East India based on our study.
2. Bioclimatism and Vernacular Architecture
Climate, socio-cultural setup, economy, building materials and technology availabilities are the main
factors that greatly influence the building architecture and its sustainability. Since climate varies from
place to place thus the favorable architectural solutions for built environment are also region specific.
Vernacular architecture constructed by the people reflects their need and socio-cultural values [6]. These
buildings are constructed using locally available materials and shows a greater respect to the existing
environment and also takes into account the constraints imposed by the climate. Vernacular architecture
is often forgotten in modern times could be the best example of harmony among the human behavior,
building and the physical environment. However, it may not be appropriate to adopt these models as
readymade solutions for modern architecture. Our advanced technical capability and cultural context
prevent us from returning to these old-fashioned architectural forms. But we can learn a lesson from the
approach of the builders who acknowledged the interdependence of human beings, buildings and
physical environment [7]. Bioclimatism is a concept that integrates the micro-climate and architecture to
human thermal comfort conditions [6]. It is revealed from different studies on vernacular architecture
that bioclimatism is a critical parameter for achieving sustainability of modern architecture [8, 9]. This
concept takes into account the solar passive techniques and micro-climatic conditions in building
design; which improves the building artificial energy efficiency and thermal comfort conditions in the
built environment.
Vernacular architecture is a term used to categorize methods of construction which uses locally
available resources to address the local needs [10]. These kinds of structure evolve over time to reflect
the environmental, cultural and historical context in which they exists. The building knowledge in these
kinds of architecture is often transported by traditions and is thus more based on the knowledge
achieved by trial and error and often handed down through the generations [11]. This kind of
architecture is greatly influenced by culture and geographical location but the most fascinating aspect is
that these architectures show identical architectural solutions in similar climates across totally different
and very distant geographical locations. This architecture is of great wealth for the modern architecture
as it represents solutions which show maximum adaptability and flexibility and thus sets an example
towards sustainability. In modern times, building materials like cement, steel and bricks are highly
energy intensive. Different study reported that the embodied energy cost as well as running cost can be
significantly reduced in climate-responsive building design [12]. Energy efficient building has potential
to reduce carbon emissions by 60% or more, which translates to 1.35 billion tones of carbon [13]. So
climate responsive building design has become a necessity rather than an option for energy conservation
and carbon emission reduction [13]. So we must not underestimate the solutions of vernacular
architecture. Rather it demands for a systematic and detailed scientific understanding.
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3. 3. Bioclimatic classification of North-East India
The weather of any place represents an integrated effect of all atmospheric variables over a brief period
of time. Climate is the average weather over a period of many years. Both weather and climate are
described by the climatic factors like solar radiation, ambient temperature, air humidity, precipitation,
wind speed and sky condition [14]. The characteristics and consequently the requirements of comfort
for each climatic zone differ from other zone. The entire northeast region has very uneven topography
and the climate of any place is affected by the topography of the particular place. The major landforms
affecting the climate of the site are mountains, valleys, water bodies and plains. Above all the whole of
northeast is heavily vegetated. All these have varying effects on the micro-climate of a place and hence
the climate has to vary from place to place. Therefore entire northeast region is reclassified freshly at
micro-climatic level [14]. This work has done with the help of the temperature data (both maximum and
minimum of monthly averages for thirty-year normal data), humidity (thirty years normal of monthly
average data at 8.30hrs and 17.30hrs), rainfall (thirty years normal of monthly data) and wind data
(thirty years normal of the percentage of winds in particular direction) collected from the Regional
Meteorological Centre, Guwahati, India. Entire northeast India is classified into three major bioclimatic
zones namely; warm-humid, cool-humid and cold-cloudy [Table 1 and Figure 1] [14].
Table 1 Specifications of re-classified bioclimatic zones of North-East India [14]
Bioclimatic zones Warm and humid Cool and humid Cold and cloudy
Maximum 30-350
C 25- 300
C 20-250
C
Summer
Minimum 22-270
C 20-240
C 14-190
C
Maximum 25-300
C 20-250
C 15-200
C
Temperature
range
Winter Minimum 10-150
C 10-150
C 5-100
C
Humidity (%) 75–90 75–95 80–90
Rainfall (mm) 1700 to 2100 1500 to 2000 >2000
Sky condition
Generally clear sky
but overcast during
monsoon
Generally clear sky
but heavy overcast
during monsoon
Occasionally clear
sky but overcast sky
rest of the year
Wind direction
Low wind during
summer and from SE,
N, & NE direction
High wind during
summer and from
E, SW & W
direction
Medium Wind from
NE, SW & W
direction
Vegetation Heavy vegetation Heavy vegetation Heavy vegetation
Figure 1 Bioclimatic zones of North-East India Figure 2 Bioclimatic chart for Cool and Humid
zone
3.1 Bioclimatic building design chart
The solar passive design strategy calculations involve the division of a particular region into meaningful
different bioclimatic zones. The bioclimatic charts are constructed for three different bioclimatic zones
of the region namely; warm and humid, cool and humid and cold and cloudy climate based on the works
15

4. of Milne and Givoni [15]. This bioclimatic building design charts will provide architects and engineers a
quick overview of the potential of appropriate solar passive design along with conventional
heating/cooling strategies, which are to be considered during the initial design stage of a building. The
climate of a given location is analyzed in its own terms and the analysis leads to certain passive solar
design strategies. The monthly climatic lines are drawn on the psychometric chart. The two end points
of the climatic lines are given by the mean minimum temperature and mean minimum relative humidity
and mean maximum temperature and mean maximum relative humidity. The proportion of the monthly
lines falling within a particular passive design strategy indicates (in terms of percentage) the potential
use of that passive design [Figure 2 and Table 2] [14].
Table 2 Passive design strategies potential for different bioclimatic zones [14]
Potential Strategies (% wise)
Cooling requirement (April May, June, July, August and September)
Climatic zones
Natural
ventilation
Passive solar
cooling
Comfort
Air-
conditioning
Conventional
cooling
Warm and Humid 16.6 0 7.6 75.8 0
Cool and Humid 16.6 0 14.2 69.2 0
Cold and Cloudy 0 22.5 44.5 31.5 1.5
Heating requirement (October, November, December, January, February and March)
Climatic zones
Natural
ventilation
Passive solar
heating
Comfort Air-
conditioning
Conventional
heating
Warm and Humid 14.0 22.5 32.5 26.5 4.5
Cool and Humid 8.0 30.8 37.5 13.7 10.0
Cold and Cloudy 1.7 37.5 15.0 0 45.8
4 Solar Passive features in vernacular buildings
A solar passive house/structure is designed such that it makes effective use of solar radiation to warm up
in winter and to block out solar radiation in summer. The design of solar houses/structures requires a
detailed understanding of the relationship among architectural textures, human behaviors, culture and
climatic factors [6]. Bioclimatic zones specification of warm and humid climatic zone shows that high
humidity and excessive rainfall are the prime factors that influence the comfort condition inside the built
space [6]. Solar radiation and wind speed and direction have also an impact in the building structures.
Due to heavy rainfall in the region, the entrances of the houses are pulled inside and half of the wall is
made up of backed brick masonry and above that the wall is made of by wood. In case of mud
architecture; the houses are made on the raised platform so that the drained water from the roof cannot
crumble to the side walls. Because of excessive rainfall it is observed that the roofs of the traditional
houses are slanting and facing two or four directions. Roofs are extended to act as overhang to protect
the wall from rainfall. We also found that the wind direction is intelligently used for natural ventilation.
Figure 3 represents the features that enhances air circulation and hence promotes natural ventilation. In
case of pukka building surkhi is used in fixing the bricks and for plastering. Study shows that 0.38 m to
0.51 m thick wall made up of surkhi give a heat gain or loss time lag from 10 to 15 hours [6]. Use of
surki is quite common in the buildings of this climatic zone. An advanced passive feature like an air gap
is maintained in the lower side of ceiling (Figure 4). This air gap is created by using two layers, one of
bamboo and the other of wood to construct the ceiling. Windows and doors are completely wooden
structure and can be partially opened depending on the resident’s requirement. Figure 5 shows veranda
is in the east and in the west side running along north to south of a school building constructed in the
year 1863. Vertical wooden structure is present to block the afternoon sun rays entering into the
classrooms. Overhang on windows is also used to block the sun rays. Almost all the houses in this zone
have rooms with ceiling height ranging from 4.57 m to 5.49 m and walls are 0.46 m to 0.51 m thick.
This height helps in the formation of natural draft to enhance ventilation [6].
A typical rural house of cool and humid climatic zone is low energy dwelling. These houses are
constructed only by using locally available materials. Orientation of the house in rural area plays a
major role. Most of the houses are east-west oriented and south facing to receive maximum solar
radiation. Figure 6 represents the bamboo, bamboo leaves and cane arrangement used to make false
ceiling and roofing. The walls of the houses are made by sandwiching a particular species of bamboo
between two layers of processed mud. Processing enhances binding property and adds porosity to mud.
Increase in porosity actually increases the water retention property of mud which intern provides
resistance to temperature change and thus helps in retaining comfort conditions [6]. In urban houses the
16

5. outer walls are 0.20 m to 0.38 m thick but in rural houses it is 0.07 m to 0.13 m thick. In both the cases
inter room partition walls are 0.07 m to 0.13 m thick and are also made up of sandwiching woven
bamboo in between two layers of processed mud [6].
In cold and cloudy climatic zone, residents are using stone blocks for constructing their houses to reduce
the cost. The place for cooking is made in such a way that it also serves the purpose of space heating.
The windows of the houses are small in size and walls are relatively thick. This helps in reducing heat
loss from inside the house. A rural low energy dwelling is generally made up of bamboo, cane and
wood. Floor of this low energy dwelling is generally elevated (0.50 m to 1 m) from the ground. Floors
of almost all the houses are made up of wooden planks. Wood being the poor thermal conductor
improves the inside comfort condition. Houses are compact and constructed on south slops of the
mountain and oriented in east-west direction to receive maximum solar radiation. The ceiling height is
very low inside the house. These houses have minimum surface to volume ratio which maximizes the
heat gain inside the rooms during daytime and minimizes the heat loss during nighttime [6].
Figure 3 Air circulations and ventilations features Figure 4 Air gap in multilayered false ceiling
Figure 5 Shading techniques to block solar radiation Figure 6 Materials and techniques used in false
ceiling & roofing
5 Thermal Performance of vernacular buildings
The adaptive approach is based on the statistical analysis of large number of thermal comfort field
studies. The adaptive approach is a behavioral approach and rests on the observation that people are not
passive in relation to their environments; but they show direct response to make themselves comfortable
at the given time and opportunity [16]. The adaptive opportunity may be provided for instance by fans
or operable windows in summer or by temperature controls in winter. An increasingly wide range of
temperature is permissible as the adaptive opportunities are increased. Individual control is more
effective in promoting comfort than in group control. Humphreys and Auliciems reported strong
positive correlations between the observed comfort temperature and the mean temperature prevailing
both indoors and outdoors during the field studies [17]. Adaptive model make use of mean monthly
outdoor temperature to estimate comfort temperature for the purpose of practical prediction. This input
data can be obtained from the nearest weather station. The adaptive model is based on extensive field
measurements and the relationship between expected clothing and outdoor climate into the empirical
statistical relationship [17, 18]. The required data is collected from Regional Meteorological Centre,
17

6. Guwahati, India and the sample data collected at Tezpur, Imphal and Cherrapunjee by using data
loggers (HOBO, USA). The data loggers were well protected from external solar radiation and winds
and fixed in the centre of the house and outside of the house to monitor the temperature at an interval of
30 minutes. The temperatures were recorded for 25 days in the month of January and April 2008
respectively. Table 3 represents the comfort temperature of different places.
It was observed that the house in Tezpur (Warm and humid zone) prevails no comfort for the entire
month of January. But for the month of April, Humphreys model predicts 5% of time comfortable and
Auliciems comfort model predicts 15% of time comfortable. Ventilation is done well by providing
sufficient number of windows and ventilators; accounts 50% of floor area. However, the house needs to
be worked on insulation level by closing leaks and providing proper false ceiling. By using adaptive
approach and running ceiling fans the comfort period can be enhanced upto 30% of the time [18].
Table 3 Comfort temperature of different places
Temp Swing
( 0
C)
Station Month
Outside Inside
Time
Lag
(hrs)
Mean
Temp
(°C)α
Mean
Indoor
Temp
(°C) β
Mean
Outdoor
Temp
(°C) β
Comfort
Temp (°C)
(Humphreys) γ
Comfort
Temp (°C)
(Auliciems) δ
January 15 10 5-6 17.1 17.2 16.3 24.7 20.9
Tezpur
April 19 9 5-6 24.8 25.7 25.3 24.7 25.0
January 25 15 2-3 13.6 13.6 14.5 23.1 18.9
Imphal
April 20 15 2-3 21.2 24.9 24.2 23.1 24.1
January 16 11 5-6 11.6 15.0 13.7 21.3 18.7
Cherrapunjee
April 19 10 5-6 18.6 25.1 24.2 21.3 23.7
α
Based on Regional Metrological Centre, Guwahati ; β
Measured at the selected house ; γ
Calculated by using Humphreys
model ; δ
Calculated by using Auliciems model
The architecture of the house in Imphal (cool and humid zone) is properly ventilated as windows
constitute about 30% to 40% of floor area but there is a need to reduce the internal heat gains during day
time so that the internal temperature swing can be maintained below 10°C. This can be achieved by
providing false ceiling, high thermal mass wall and minimizing the unwanted leakage. From the
temperature profile it has been found that the time lag is 2 to 3 hours. For the month of January;
Auliciem’s comfort model predicts comfort for 5% of time. For the month of April, Humphreys and
Auliciems comfort model predicts comfort for about 40% of time. This comfort time can be improved
further to about 55% of time providing false ceiling only.
The indoor temperature variation in the house at Cherrapunjee (cold and cloudy zone) for both the
months of January and April is permissible. By using Humphreys and Auliciems comfort model for the
month of January it is found that there is no thermal comfort inside the house (Table 2). So for the
winter months internal heat gains need to be increased and heat loss needs to be minimized. For the
month of April, Humphreys and Auliciems comfort model predicts comfort for about 70% of time.
6 Comfort Status of naturally ventilated vernacular buildings
Thermal comfort is a subjective response and is affected by local environmental variables. Figure 7
represents temperature(0
C) corresponding to the neutral on thermal sensation scale and Figure 8
represents the relative humidity on sensation scale. It has been noticed that there is a difference of ±20
C
from neutral vote for each climate zone. For warm and humid climate; the neutral temperature is 260
C
and relative humidity (RH) is 80%, for cool and humid climate it is 240
C and RH 65% and for cold and
cloudy climate it is 220
C and RH 60%. In the figure, we also observed that the extremes of comfort zone
varies by 60
C in each climate i.e. for warm and humid climate it is 230
C (-1) to 290
C (+1), for cool and
humid climate it is 20.50
C (-1) to 260
C (+1) and for cold and cloudy climate it is 180
C (-1) to 240
C (+1)
respectively. It can be conclude that the comfort varies over the range of approximately 60
C. In case of
naturally ventilated buildings these status can be easily converged towards comfort by having through
various adaptations techniques viz. changing clothing level, running fan, opening and closing windows
etc. The humidity is quite high but in free running building it is also difficult to control. So it can be
taken care only by providing proper ventilation and enhanced air circulation arrangements by using
natural wind directions [19].
18

7. -3
-2
-1
0
1
2
3
10 15 20 25 30 35 40
Temperature (0C)
S
e
n
s
a
tio
n
S
c
a
le Warm and Humid
Cool and Humid
Cold and Cloudy
30
40
50
60
70
80
90
100
-3 -2 -1 0 1 2 3
Sensation Scale
R
e
l
a
t
i
v
e
H
u
m
i
d
i
t
y
(%
)
Warm and Humid
Cool and Humid
Cold and Cloudy
Figure 7 Comfort temperature range Figure 8 Relative humidity variation against thermal
sensation votes
Social and cultural values are closely associated with building design and function. It has been noticed
as the house become old, the social, cultural and visual comfort decreases. This happens due to increase
in family strength, decrease in privacy, and change in life style of occupants. It is also observed that the
approximate time for modification in the existing building plan (i.e. addition of extra rooms or internal
modifications) is 20 to 25 years [2]. So after re-construction of the existing houses, it affects the other
important comfort factors. It obstructs the air movement thus affecting the ventilation. Overall thermal
ratings of the about 70% of the houses are below average. This is because of low insulation levels. It has
been observed that the houses in cold and cloudy climate are showing fairly acceptable values of
illumination level i.e. 108 lux/m2
. But houses in warm and humid and cool and humid climate has very
low illumination levels i.e. 22 lux/m2
. This can be improved by replacing wood pans by glass pans in
windows and ventilators [19].
7 Energy efficient bioclimatic building design strategies
Warm and humid climatic zone
The building should be located on the windward side or crest to take advantage of cool breezes. Since
the humidity level is quite high (uncomfortable range) throughout the year; water bodies should be kept
out of design considerations as far as possible. Building should be spread out with large open spaces for
unrestricted air movement. The buildings are preferably oriented along an east-west direction to
minimize the solar radiation on external surfaces to reduce heat gain. This region is heavily vegetated so
shading due to vegetation could be used in an advantageous way. Very thin roofs having low thermal
mass, such as asbestos cement sheet, galvanized tin sheet do require insulation, as they tend to radiate
the heat into the interiors very quickly during daytime and vice versa in night time. Direct sunlight is not
desirable for thermal reasons [20]. The use of false ceiling made up of locally available material (cane
or bamboo) will be an attractive solution to reduce heat gain inside the building. If adequately sheltered,
exposed brick walls and mud plastered walls is better as these walls will absorb the humidity and
helping the building to breathe. Since humidity level is quite high, cross ventilation becomes important
aspect in buildings of this region. Doors and windows must be provided with venetian blinds or louvers
to shelter the rooms from direct sun, as well as for the control of air movement. Openings of
comparatively smaller size can be placed on the windward side, while the corresponding openings on
the leeward side may be bigger for facilitating a plume effect for natural ventilation. The openings must
be shaded by external overhangs. Outlets should be provided at higher level to vent hot air. The walls
should be painted with light pastel shades or whitewashed.
Cool and Humid Climatic Zone
In this climatic zone the building structure on the windward slopes is preferred for getting cool breezes
because the humidity level is very high throughout the year. An open and free layout of the buildings is
preferred. It is preferable to have the building orientation in the north-south (bedroom may be located on
the east side and an open porch on the S-SE side), while the western side should ideally be well-shaded.
Sunlight is desirable except in summer, so the depth of the interiors may not be excessive. Tilted roof is
19

8. preferred as like warm and humid climatic zone. If adequately sheltered, mud plastered walls works
well by absorbing the humidity and helping the building to breathe. The arrangement of windows is
important for reducing the heat gain. Windows can be smaller on east, west and north side while larger
on south side to increases winter heat gain and reduces summer gain. All windows should be shaded
with chajjas /overhangs of appropriate length such that direct sunlight enters room during winter days
but gets completely blocked during summer. Pale colors are preferable; dark colors should only be used
in recessed places protected from the summer sun. This climatic zone persists at high altitudes in the
region where sky is generally overcast, the whole hemisphere of the sky acts as a source of light. The
luminance of the sky is sufficiently high to give adequate light in living space [20].
Cold and Cloudy Climatic Zone
In cold climates, heat gain is desirable. Hence, building should be located on the south slope of a hill or
mountain for better access to solar radiation. At the same time, the exposure to cold winds can be
minimized by locating the building on the leeward side. Buildings in cold climates should be clustered
together to minimize the exposure to cold winds. In this climate zone, buildings must be compact, with
small surface to volume ratio. This is because the lower the surface area, the lower the heat loss from
the building. Windows should preferably face south to encourage direct solar heat gain. To the extent
architecturally feasible, locate the rooms most used during the day along the southern side of the home
to take advantage of direct solar heat gain. A solar air collector can be incorporated on the south facing
slope of the roof for hot air and it can be used for space heating purpose. Skylights on the roof admit
heat as well as light in winters. The skylights can be provided with shutters to avoid over heating in the
summer. The south facing walls could be of high thermal capacity (such as Trombe wall) to store
daytime heat for later use. Hollow and lightweight concrete blocks are also quite helpful. On the
windward or north side, a cavity wall type of construction may be adopted. It is advisable to have the
maximum window area on the southern side of the building to facilitate direct heat gain. These should
be sealed and preferably double glazed. Double-glazing helps to avoid heat losses during winter nights.
The external surface of the walls should be dark in color having high absorptivity to facilitate heat gains.
From a physical as well as psychological point of view, an excess of day lighting is advantageous in this
region. The over-lighting leads to an increased sense of well-being. Hence, windows must have
minimum shading [20].
8 Conclusion
This paper presents a systematic approach towards energy efficient bioclimatic building design. North-
east India is classified into three bioclimatic zones with specification details. Bioclimatic building
design charts for each climatic zones is developed and different design potentials is determined for both
summer and winter months separately. Detailed survey of 75 households were carried out and also
temperature, relative humidity and illumination data are collected and comparative study has done to
access the thermal behavior of vernacular architecture. It is found that for pre-summer months; houses
shows satisfactory thermal behavior but in winter month shows poor performance. The illumination
level is below the standard across all the three climatic zones. We also found out the vernacular houses
have number of solar passive features that minimizes heat gain, promotes ventilation in warm and
humid climate. In cold and cloudy climate houses are compact and constructed in such a way that house
receives maximum solar radiation. The range of comfort temperature is also found out to be 60
C, which
is quite satisfactory and represent high scope for energy conservation. We found that the main factors
that influence the building design and sustainability are socio-cultural issue and micro-climate. Finally
different energy efficient bioclimatic building design strategies are suggested for modern architecture.
We have generated quantitative information and hopes that this information will be useful for scientists
and engineers those are working the field of sustainable architecture and sustainable habitat in the
region.
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[13] Tzikopoulos AF, Karatza MC, Paravantis JA. Modeling energy efficiency of bioclimatic
buildings. Energy and Buildings 2005; 37(5):529– 44.
[14] Singh MK. Mahapatra S. Atreya SK. Development of Bio-climatic zones in North-East India.
Energy & Buildings. 2007:39(12); 1250-1257.
[15] Milne M. Givoni B. Architectural Design based on Climate. In: Watson D, Editor, Energy
Conservation through Building Design, New York. McGraw Hill, 1979, pp 96-113.
[16] Singh MK. Mahapatra S. Atreya SK. Thermal Performance Study on Vernacular Architecture
of North-East India. International Congress on Renewable Energy (ICORE 2008), 16-17
October, 2008 Chennai, India (Accepted for presentation).
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[18] Nicol JF. Humphreys MA. Adaptive thermal comfort and sustainable thermal standards for
buildings. Energy & Buildings 2002; 34(6):563-572.
[19] Singh MK. Mahapatra S. Atreya SK. Comfort Status in Naturally Ventilated Buildings of
North-East India. Renewable Energy Asia - 2008: An International Conference and 4th SEE
Forum Meeting. IIT Delhi, New Delhi, December 11-13, 2008 (Accepted for presentation).
[20] Singh MK. Mahapatra S. Design Guidelines for Construction of Energy Efficient Buildings in
North-East India. Proc. International Congress on Renewable Energy (ICORE), February 8-
11th
, 2006, Hyderabad, India.
Brief Biodata of Presenter:
Mr. Manoj Kumar Singh did M.Tech in Energy Technology from Tezpur University. Presently he is
doing PhD at Indian Institute of Technology, Delhi, India. His area of PhD work is Bioclimatic Building
Design. Apart from this; his areas of interest are solar passive design, CFD study of buildings. He has
published 10 papers in international journals and conferences. He was the recipient of MNRE
fellowship (Ministry of New and Renewable Energy, Govt. of India) during his M. Tech. programme.
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