Building external walls in hot, arid regions is critical to environmental control in architectural design, due to their role in heat transfer. Providing thermally comfortable conditions in building interiors is a primary goal in architectural design, as the external wall of a building acts as a protective skin, making its design critical to achieving thermal comfort and energy efficiency.

However, many buildings in hot, arid regions fail to meet environmental design standards, resulting in high energy consumption and carbon dioxide emissions. For example, residential buildings consume up to 55.5% of the total electricity in these regions, with air conditioning loads accounting for a large portion of this consumption.

In this regard, a team led by Dr. Islam Sallam, from the College of Engineering, has conducted research to produce an external wall section design. This novel design comprises isolating the interior space from the external environmental factors. Moreover, it absorbs and transfers the internal heat to outside in one direction utilising a water cycle. These features take advantage of the large daily thermal range in hot arid regions. Digital software has been designed, including the exothermic wall assessment (EWA). This software utilised thermodynamic physical equations to evaluate the efficiency of the proposed design and compare it with four different traditional isolated wall sections.

The design of this system represents a challenge, as heat is always transferred from places with higher temperatures to places with lower temperatures, which makes it theoretically impossible to transfer heat directly to the exterior without consuming energy. However, studies have shown that the targeted area is characterised by a large daily temperature difference of up to 20 degrees Celsius. This opens the way for an innovative solution to create a completely insulated thermal tank integrated into the wall containing a fluid with a high specific heat which is capable of absorbing large amounts of heat during the day. The fluid is then transferred to an external tank to release the absorbed heat into the surrounding environment, allowing the cooling cycle to resume the next day.

The results showed that the proposed design outperformed the four traditional isolated wall sections in absorbing heat from interior spaces during daylight hours. Moreover, it did not re-radiate heat to the interior space during night hours, which demonstrates its potential to achieve thermal comfort in buildings in hot, arid areas without consuming large amounts of energy.