Impact of thermal mass on indoor temperature stability?

Understanding Thermal Mass in Rammed Earth Construction

Thermal mass refers to the ability of a material to absorb and release heat. In rammed earth construction, thermal mass is often achieved through the use of dense, high-mass walls constructed with compacted soil mixes and formwork. The ideal thermal mass is achieved with a soil mix that contains a high proportion of sand and silt, which provides a high density and low thermal conductivity. A mix design of 60% sand, 20% silt, and 20% clay can provide a thermal mass of approximately 2.5 kg/m³.

Designing Thermal Mass for Desert Climates

In desert and arid climates, thermal mass is essential for maintaining a stable indoor temperature. Rammed earth walls can be designed to take advantage of this principle by incorporating a 200-300 mm thick wall, which can absorb and release heat slowly. The use of a thermal mass wall can reduce indoor temperature fluctuations by up to 50% and maintain a consistent indoor temperature of 22-25°C (72-77°F) even in extreme external temperatures. This is particularly beneficial in regions where outdoor temperatures can fluctuate by up to 20°C (36°F) in a single day.

Maximizing Thermal Mass in Rammed Earth Construction

To maximize thermal mass in rammed earth construction, builders can employ various techniques, including using a high-mass soil mix, incorporating insulation into the wall cavity, and designing the building with large overhangs to reduce direct sunlight. Builders can also use a formwork system that allows for precise control over wall density and thermal mass. By incorporating thermal mass into rammed earth construction, builders can create a comfortable and energy-efficient building that is well-suited to desert and arid climates.