Predicted percentage dissatisfied (PPD) model evaluation of evaporative cooling potentials of some selected cities in Nigeria

Abstract

In some developing nations like Nigeria, poverty and epileptic power supply are the twin problems impeding people from the use of refrigeration-based air conditioning systems to achieve thermal comfort. Direct evaporative cooling is a viable option of achieving thermal comfort especially in hot and dry climates. Direct evaporative coolers, apart from their low power requirements, are relatively cheap and are environment friendly. This paper attempts to estimate the direct evaporative cooling potential of some selected cities in Nigeria using the predicted percentage dissatisfied (PPD) model. The model stipulates that a conditioned space is thermally comfortable if not more than 20% of the occupants are thermally unsatisfied. These selected cities are Enugu, Kano, Jos, Maiduguri and Mubi-South. The computed PPD for the months of January through December for the selected cities were determined. The computed PPD of these cities reveal the suitability of using evaporative coolers in the months of January and December for Enugu; all the twelve months for Kano; January, February, March, April, May, September, October, November and December for Jos; January, February, March, April, May, June, October, November and December for Maiduguri and, all the twelve months for Mubi-South, because their computed PPD in these months are less than 20%. This, however, shows that there is high potential of using direct evaporative coolers in Kano, Jos, Maiduguri and Mubi-South which can be attributed to the relative high outdoor temperatures and low relative humidity. Apart from Enugu, direct evaporative coolers are recommended in these areas and in areas with similar climatic characteristics.

A review of common natural ventilation and evaporative cooling systems for Greenhouses and the Nigerian reality

“…A good example is the development of evaporative coolers that use palmfruit fiber as cooling pad material and effects a temperature drop range of 4 o C -13 o C at 96.8% relative humidity ambient air and provides up to 98% cooling efficiency with a 2,529W maximum cooling capacity designed by [63] which also consumes half the power of a typical vapour compression refridgerator of same volume. Study on predicted percentage dissatisfied (PDP) model evaluation of evaporative coolng potentials of some selected cities in Nigeria was also performed by [64]. The significance of active evaporative cooling systems in the shelf life enhancement of vegetable (red and green tomatoes) for minimizing post harvest losses have been studied by [65] and the performance evaluation of a composite paddled evaporative cooling storage bin by [66] are a few out of many local research on evaporative cooling systems.…”