Thermal Performance of Ancient Underground Dwellings in Tunisia

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Thermal Performance of Ancient Underground
Dwellings in Tunisia

• MONCEF KRARTI, Ph.D.
• Joint Center for Energy Management
• CEAE Department, CB 428
• University of Colorado at Boulder

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Presentation Outline

• Why Underground Dwellings
• Ancient Underground Dwellings
• Tunisian Troglodyte Dwellings
• Field Measurements
• Summary and Conclusions

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Why Underground Dwellings

• ADVANTAGES
• Protection from stressful climates
• Reduced maintenance cost and energy cost
• Preservation of land
• Increased safety from vandalism
• Reduced noise problems
• DISADVANTAGES
• Claustrophobia (Lack of windows)
• Poor Ventilation

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Ancient Underground Dwellings

• Earth-Sheltered House in Northern China
  (Semi-Arid Climate)
• Underground Settlements in the Cappadocia Area
  (Center of Turkey)
• Troglodyte Dwellings in Southern Tunisia (Arid
  and Hot Climate)

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Tunisian Troglodyte Dwellings

• HISTORY Developed by the berbers (first known
  inhabitants of north Africa). As early as 500 BC
  and as late as 1900 AC.
• LOCATION Matmata plateau north of the Sahara
  desert (altitude 500 m.).
• ADVANTAGES
• Easy soil to excavate (free of stones)
• Shelter against invaders attack
• Protection from hot and arid climate

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Tunisian Troglodyte Dwellings

• Types
• (a) Vertical design with central patio
• (b) Horizontal design on mountain slopes

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Floor plan of one section of the Marhala Hotel in
Matmata
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Field Measurements

• Parameters Measured Air temperatures and
  relative humidity both outdoors and indoors
• First Field Study Golany (1982) using
  Psychrometer
• Present Field Study Krarti (1997) using sensors
  and a data acquisition system

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Monthly Soil temperature Variations at Various
Depths
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Hourly dry-bulb temperature measured during 1982
for winter


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Hourly dry-bulb temperature measured during 1982
for summer
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Hourly dry-bulb temperatures measured during
summer 1997
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Indoor temperature variation with height at 1
p.m. in the back and the front of the room (site
6)
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Thermal conditions in various rooms in the
Marhala hotel at 3 p.m. of July 24, 1997
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Comparison of indoor environment for typical
winter and summer days in a subterranean dwelling
and a conventional above-ground house in Matmata
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Summary and Conclusions

• Field measurements indicated that the troglodyte
  dwellings provide more comfortable environment
  than above-grade houses in the Matmata region
  throughout the year.
• The optimum depth for the dwellings is 10 m. as
  discovered by the first inhabitants of Matmata.
• Design of Matmata dwellings needs to be improved
  to correct for lack of ventilation and natural
  lighting.