Thermal Monitoring on an Earthbag Building in Mediterranean Continental Climate
Abstract
Earthbag and superadobe are low-cost and environmentally friendly building techniques that use the raw earth to build structural walls, usually in dome shape. This research analyzes the thermal performance and comfort of an earthbag building located in Mediterranean continental climate by experimentation in real conditions. The monitoring consisted in data collection of air temperature and humidity, horizontal solar radiation, and surface wall temperatures in summer and winter periods, using free floating and controlled temperature experiments. Passive design strategies for winter were tested, such as high thermal inertia of walls and direct solar gain. Natural ventilation was also tested in summer period. Results showed a very stable interior temperature in the earthbag building and the increase of day temperatures due to the direct solar radiation collection through the glassed openings located in the east and south façade. However, the high U-value of the earthbag walls and the lack of internal loads caused the interior temperature to be out from the comfort range, and a heating system was required with an energy consumption of 1-1.7 kWh/m2 per day, in winter. The direct contact of the building with the ground caused a high relative humidity in the dome in both summer and winter periods that could be reduced by using natural ventilation. Night ventilation was a suitable passive strategy in summer period to reduce the average temperature level in the dome.