Evaluating coefficient of performance and rate of moisture loss of some biomass humidifiers materials with a developed simple direct stand-alone evaporative cooling system for farmers

Abstract

The purpose of this study was to investigate the feasibility of deploying direct evaporative cooler with Jute fiber, palm fruit mesocarp fiber and wooden charcoal as humidifier in Nigeria. High cost of imported evaporative coolers and humidifiers can discourage farmers and limited adoption of evaporative cooling technology. For this purpose an experimental direct evaporative cooling test rig was developed and assembled in south western Nigeria with biomass humidifier. The evaluation parameters were the humidifying efficiency, the rate of moisture loss, coefficient of performance and sensible heat ratio. The humidifier presented average cooling efficiency of 55.9 to 78.62 %, average rate of moisture loss of 1.37 × 10 -3 to 2.61 × 10 -3 kg/s, average COP of 8.48 to 23.42 (EER of 11 to 78) and average sensible heat ratio of 1.28 × 10 -4 to 4.06 × 10 -4 for the air velocity of 3.0 to 4.5 m/s. The obtain performance can be better in a dryer month or nearly impossible in a very wet month as the humidifying efficiency of direct evaporative coolers are found to diminish at high humidity. To avoid casting doubt on the effectiveness of direct evaporative cooler by farmers, it should only serve as stop gap preservation equipment and deployed during the favorable weather condition especially during the winter when the air is dry. These can be identified from the metrological charts of the chosen location.