4.3 Buildings in Shanti Nagar, Orissa, India

4.3.1 Geographical location and climatic characteristics
4.3.2 The monitored buildings
4.3.3 Climatic performance and conclusions

The main points:
· Unprotected southern walls lead to overheating.
· FCR (Fibre Concrete Tiles) and clay tiles perform similarly.
· Double layer of tiles has no significant influence on the indoor air temperature, but certainly on the surface temperature which is not monitored.
· Buildings with a high storage mass are clearly warmer at nighttime, but not much cooler in daytime because of the high ventilation rate.

Source: AMG India International Leprosy Rehabilitation Centre, Shanti Nagar
Monitoring of performance: H.U. Lobsiger

4.3.1 Geographical location and climatic characteristics

Shanti Nagar lies in a hot and arid region in India, 220 km from the coast, at an altitude of 400-m above sea level and a latitude of 20o North.

The climate is hot and dry in the summer season (March to June) with temperature variations between a maximum of around 50°C and a minimum of 20 - 30°C, thus a large diurnal temperature swing. Winter (November - February) temperatures vary between a maximum of 20 - 30°C and a minimum of 4 - 10°C. Measurements were taken in March 1990, when the outdoor temperature varied between 21°C at night and 35°C in daytime.

4.3.2 The monitored buildings

The four houses that were compared are all residential buildings of single story structures.

Fig 4/10 House 1

· Ratio window to floor area: 30%
· Walls: Brick, white plastered on outside, 30 cm;little sun protection on the southern side.
· Roof: Clay tiles
· Ventilation: Good
· Floor: Mud

Fig 4/11

· Ratio window to floor area: 28%
· Walls: Brick, white plastered on outside, 40 cm.
· Roof: Double FCR sheet with 8 cm ventilation space (FCR = Fibre Concrete Roofing, 10 mm thick).
· Ventilation: Poor to moderate
· Floor: Mud

Fig 4/12 House 3

· Ratio window to floor area: 16%
· Walls: Brick pillar structure with clay infill, 40 cm; outside color brown.
· Roof: Single FCR sheet
· Ventilation: Moderate
· Floor: Mud

Fig 4/13 House 4

· Ratio window to floor area: 21%
· Walls: Brick pillar structure with clay infill, 40 cm; outside color brown, large storage mass.
· Roof: Single FCR sheet, alternatively clay tiles
· Ventilation: Moderate
· Floor: Mud

4.3.3 Climatic performance and conclusions

Fig 4/14

· During the daytime, house 1 is clearly hotter than all the others, up to 6°C. This is mainly due to the unprotected southern wall and window with very little roof overhang. The reduced thermal storage capacity and insulation of the outer walls (thinner walls) are also contributing factors.
· No difference could be observed between FCR roofing and clay tile roofing.
· Although no clear difference between double FCR sheeting and single sheeting could be observed, there is a clear advantage with double sheeting because of the lower inner surface temperature. This was not measured, but observation by the inhabitants supports it. Moreover, recent research works at the CECAT in Habana, Cuba, have shown, that in such a case the inner surface temperature of a ventilated double sheeting construction is lower by approximately 8°C.
· At night all houses perform similarly and have a temperature about 6°C higher than the outside temperature. This is due to the relatively high thermal storage capacity. House 1 with the least storage capacity is slightly cooler. With increased night ventilation it might be possible to decrease night temperatures.
· Houses with mud-walls are clearly superior in the daytime compared to brick structures because of the larger storage mass and also because they are less ventilated. The performance at night could be further improved by increased ventilation, but the inhabitants are not concerned because they sleep outdoors.