The document analyzes the thermal comfort of different types of rural mud huts in Jharkhand, India. It studies huts with varying degrees of compactness and courtyard inclusion. Temperature measurements and software simulations were used to compare thermal performance in summer and winter. The most compact hut had the highest summer temperatures and most discomfort hours. Huts with greater perimeter to area ratios performed better in summer. In winter, the most compact hut lost the least heat. Overall, a moderately spread out plan with good ventilation provided the best thermal performance year-round for the local climate.

1. Comparative analysis related to
compactness of dwelling units and its effect
on thermal comfort amongst rural mud huts
in composite climate in India.
Janmejoy Gupta
Assistant Professor: Deptt. Of Architecture
Birla Institute of Technology, (BIT) Mesra
Ranchi, Jharkhand, India.
Email: janmejoy71@gmail.com
Dr.Manjari Chakraborty
Professor: Deptt. Of Architecture, BIT,Mesra, Ranchi.
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4. Introduction
As per the Census of India, 2011, 75% of the total population in the eastern
state of India, Jharkhand, live in the rural areas.
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6. Research Hypothesis.
1. In the area having composite climate in Jharkhand, compact floor plans
show better thermal performance.
And,
2. Dwellings with courtyards, whose perimeter-area ratios vary, i.e. dwellings
which range from being quite compact to being quite spread out, show better
thermal performance in this region.
Compact internal planning implies low perimeter by area ratio. The three
dimensional extrapolation of perimeter by area ratio gives surface-volume
ratio.
Since the heights of all the single storied mud huts covered in this research was
roughly the same, perimeter by area ratios were considered as an index for
comparing the extent of thermal comfort inside the three studied types of
dwellings. ACE CONFERENCE-2016, SINGAPORE, 25-
26 APRIL 2016.

7. How the two conflicting attributes, i.e. compactness of built form and
planning with courtyards stack up against each other is seen to in this
research.
• On what aspects do the thermal comfort levels inside a mud hut
depend?
• To what extent does it depend on the compactness of planning and on
the presence or absence of courtyards?
• These are some of the questions whose answers are sought in this
research paper.
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8. Krishan et al (2001), states that in case of radiative gains or losses, the perimeter is a crucial factor.
Greater the Perimeter to Area ratio (P/A), greater the radiative heat gain during the day and the
greater the heat loss at night. In hot climates the P/A ratio should be kept to a minimum to cause
minimum heat gain.
Housing Forms and thermal comfort: a brief review.
Bansal and Minke (1988) in their exhaustive study of rural dwelling units in the different climatic
regions of India also states that in the composite climatic area, compact floor plans show better
thermal performance.
Szokolay (2004) also states that it is advisable to present the least surface-area for a given volume.
As per Koenigsberger et al (1997) in composite climates moderately compact internal planning of
houses will be of benefit for most of the year.
Again, Fathy (1973), Koenigsberger et al (1997), Bansal and Minke (1988), Yannas (2001), Roaf
(2001), Szokolay (2004) and others have suggested that the courtyard type dwelling units are a
favourable solution in composite climatic regions.
Bansal and Minke (1988) in their study on traditional rural dwelling units in the composite climatic
region, emphasizes on the courtyard as a buffer space and as a moderating influence on
microclimate. ACE CONFERENCE-2016, SINGAPORE, 25-
26 APRIL 2016.

9. Studied Types of dwellings.
The three sub-types of dwelling units with courtyards which have
been chosen for the study are shown in next slide. The three
types that are explored in this research have similar floor areas,
wall heights and internal volumes. The internal floor area for
each design is close to 100 square metres and the floor to roof
top height is approximately 4 metres. The walls are made of 450
mm thick mud walls and roof of burnt clay tiles. The sizes of
the window-like openings are approximately 0.4 meters by 0.4
meters. All three of the dwelling units have window-like openings
on both the north and south walls. (Refer Table in next slide).
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12. Research Methodology: Temperature Measurements and Software Simulation.
To obtain an adequate building performance data several steps were taken, namely:
•Identify villages in composite climatic region nearby Ranchi.
•Identify different types of courtyard type dwellings with varying perimeter-area ratios in the
identified villages.
•Carry out detailed temperature measurements in peak of summer and peak of winter. Peak
summer and peak winter identified by studying previous year’s climatic records.
•Carry out Software simulation after digitally recreating three chosen sample units for calculating
number of discomfort hours due to excess heat and excess cold through the year in each of the
three dwelling units.
•Verify software simulation results through actual temperature measurement records.
•Identify extent of thermal comfort enjoyed inside sample dwelling units in summer and winter.
•Identify which amongst the studied dwellings show better thermal performance in summer and
winter and ascertain the reasons for the same.
•Infer whether compact dwellings show better thermal performance. ACE CONFERENCE-2016, SINGAPORE,
25-26 APRIL 2016.

13. According to the default values programmed into the simulation software,
following ASHRAE Standard 55-2004, a range of 19.4°C (67°F) and 27.77°C
(82°F) is ideal for thermal comfort.
For calculating number of hours of discomfort hours due to excess heat or
excess cold through software simulation, this range of temperatures are used
as default values for maximum and minimum comfortable temperatures.
The adaptive comfort model, which applies to spaces where people can open
and close windows or voids, (ASHRAE Standard 55 -2004), was used to
calculate the number of thermal discomfort hours.
The U (Thermal Transmittance) values of 450 mm mud wall and 100 mm
thick burnt clay-tile on bamboo rafters are entered into the Ecotect
Simulation software for number of hours of thermal comfort calculations.
To allow the analysis of daily variations within each dwelling, data loggers
were used to measure and acquire hourly temperature data.
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14. Average Measured Data during Peak Summer.
Recorded average temperatures in week
from 29th May to 4th June during hottest
period of year.
Recorded average temperatures in week from
29th December to 4th January during coldest
period of the year respectively.

15. Comparative Analysis between the three sub-types of
courtyard dwellings.
Temperature Measurements inside different Types of Courtyard Dwelling Units
selected for detailed study at different times of the day and night on 29th May in
hottest week of the year. ACE CONFERENCE-2016, SINGAPORE, 25-
26 APRIL 2016.

16. Comparative Analysis between the three sub-types of
courtyard dwellings.
Temperature Measurements inside different Types of Courtyard Dwelling Units
selected for detailed study at different times of the day and night on 4th
January in the coldest week of the year.
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17. Simulated Data.
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18. Conclusions.
The most compact dwelling of the three studied dwellings, the sample hut sub-
type 1, with a perimeter-area ratio of 0.3, records the highest temperatures
during summer and also shows the greatest number of discomfort hours due
to excess heat.
On the contrary, dwellings with greater perimeter-area ratios (0.8 and 0.65)
show better thermal performance in summer on the basis of simulations and
measured data.
Thus, compactly planned dwelling units do not necessarily show better
thermal performance than less compactly planned dwellings.
The best thermal performance in summer is shown by the Sample Hut 3, with a
perimeter area ratio of 0.65.
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19. Thus neither does having a compact plan, nor does having a courtyard
guarantee good thermal performance in summer, though in most cases
having a properly placed courtyard that encourages natural ventilation
does help.
Its about optimizing design variables.
In Ranchi’s prevailing climate moderately spread out plans with good
access to natural ventilation work best as exemplified by the
comparatively better thermal performance of the U-shaped Sample
dwelling Unit 3 with a perimeter-area ratio of 0.65.
However, the winter-time performance of the Sample Hut 1 is best amongst
the three studied dwellings. Thus, the compactly shaped dwelling loses the
least amount of heat.
Conclusions.
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20. Thanks for your patience…
That’s All !!!
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26 APRIL 2016.