The geothermal potential of underground buildings in hot climates: Case of Southern Algeria

Underground buildings are one of the most effective old and modern techniques, at the same time to meet the trade-off between thermal comfort and low energy consumption in hot and arid climates, through the soil thermal properties, which can be applied as a heat capacitor for moderating indoor temperatures. This research aims to improve the thermal comfort and energy efficiency of underground buildings compared to aboveground buildings in hot and arid climates based on yearly energy consumption. The experimental measurements of soil temperatures at different depths were compared to the numerical results of the Kasuda equation. Furthermore, TRNSYS software simulation findings were validated by monitoring the temperature of an underground room in Ouargla, Algeria, using digital temperature sensors. The findings revealed that an underground structure with a depth of 2.34 m decreases cooling energy demand considerably during the summer season. Furthermore, with and without state support, the investment return time was predicted from 6.5 to 3.25 years, respectively.

Automated summary

The research demonstrates that increasing the depth of underground buildings can significantly reduce cooling energy demand during the summer season, and the investment return time can be reduced from 6.5 years to 3.25 years even without state support.