Conference article

An experimental study to determine the net flux of long wave radiation from the earth’s surface to the atmosphere in Owerri; south east Nigeria for passive cooling applications is presented. The values of the effective sky temperatures are also determined. The experimental rig which is a thermal radiator consists of a flat mild steel plate of dimensions 152.2cm x 38.1cm x 0.3cm coated with high emissivity black paint. A copper tube was used to form five turns and then soldered to the steel plate. Water from a well insulated tank placed at about 0.8 m above the surface of the thermal radiator flowed through the radiator. Thermocouples were strategically inserted on the radiator assembly to measure the plate temperature and water temperature as it flowed along the copper tube. The tests were conducted under the meteorological conditions of ederal University of Technology; Owerri for the period covering March to May; a period often free from the harmattan dust haze. The results revealed that a net long-wave nocturnal cooling power of 66.1 W/m² is possible. These results are in the same order of magnitude with those obtained elsewhere with similar climatic condition as Owerri; Nigeria.

Nocturnal cooling; Experimental; Long wave; Passive cooling; Radiation