A sustainable bio-inspired cooling unit for hot arid regions: Integrated evaporative cooling system in wind tower

•This study suggested a bio-inspired cooling unit for buildings in the hot arid regions.•The average cooling efficiency of the design is 82.4%.•Cooling efficiency is affected by air’s humidity, dry bulb temperature and air velocity.•The tests showed that the cooling ability of clay plates increases when it is covered by wet fiber.•Jute fiber can be replaced by another sustainable wetted layer covering the clay plates. The high energy consumption for air conditioning in buildings is a serious concern due to its consequences on the earth's ecological life. This study presents a new passive cooling design for buildings inspired by the morphological and physiological cooling mechanism in the nasal turbinate of camels. The main cooling unit consists of clay cylinders shaped like onion rings covered by two layers of jute fiber and installed in a wind tower. The clay plates were manufactured, and the wind tower was built in one of the desert cities in Yemen to experimentally examine and evaluate the performance of this design for ten consecutive days starting from 9 a.m. till 9 p.m. The results confirmed the applicability of the bio-inspired design to efficiently decrease the air temperature by an average of 14.6 °C and increase the relative humidity of the air by 57.5% on average. With only 1.20 m height, this design was able to drop the temperature by 19.8 °C achieving a considerable cooling efficiency in comparison with the rest cooling designs with the high heights that installed inside wind tower. The zero-energy cooling design can be a viable alternative for the highly-consumed mechanical cooling equipment.