A team of researchers in Qatar and the UK are adapting cooling technology from ancient Babylon for use in modern buildings. The passive, energy-efficient system is based on the principle of indirect evaporative cooling and aims to make the urban environment of desert cities more sustainable.
Modern cities in the Middle East in general, and in Qatar and the GCC in particular, have massive power demands due to the ubiquitous use of inefficient air conditioning units. This air conditioning places huge demands on power plants at the hottest times of the day, just at the time electricity is most needed in other areas.
Now, Dr. Hatem Ibrahim of Qatar University and Dr. Rabah Boukhanouf of the University of Nottingham, both PIs on the QNRF-funded project, have developed a low-energy air conditioning system with practical applications in modern architecture.
This novel application of ancient technology turns dry, warm air into dry, cool air, through a heat transfer procedure using sealed copper pipes - a modern improvement over a vase of water or pond. The devices also use a ceramic material as a container for the water reservoir. The whole unit can be integrated into building elements, like the wall or ceiling, or they can be standalone units.
The key to the cooling aspect is the use of heat pipes - an existing technology adapted for this principle. The units consist of porous ceramic material tubes filled with water and combined with heat pipe technology. Air movement over the wet ceramic tubes causes water to siphon through the pores to the tubes’ surface where it evaporates and removes heat from the heat pipes. The heat pipe is a heat transfer interface device which carries heat from the dry channel to the wet channel, hence reducing the temperature of the air supply to the building without adding moisture.
Two standalone units have been tested in Doha and Nottingham and have shown to be effective at affecting a 10-12 degree C temperature drop between the input and output air streams. However, the intake air has to be dry, so humid environments or coastal regions present a problem for this technology as it stands. A new research proposal to address this problem is being prepared in light of this finding.
A standalone unit with the relevant parts and air flow labelled.
A schematic diagram of a standalone unit depicted in the photo above.
Novel Passive Air Conditioning System