Influence of engineering parameters on performance of pad fan evaporative cooling system in mushroom production units

Abstract From July to September 2021, an experiment was conducted in Gharbia Province, Egypt (30.49° N, 30.59° E), involving two mushroom production units. Evaporative cooling is a vital technique for mitigating heat stress in agricultural structures. To enhance its accessibility and practicality, the study proposed the use of locally available materials that can be easily sourced by farmers. The objective was to identify the optimal water flow rate, fan air velocity, and indoor air temperature required to maintain thermal comfort within mushroom production units using an evaporative pad cooling system. To achieve this, a pre-experimental phase was conducted to examine the engineering parameters influencing system performance, employing two types of pad materials: luffa and cellulose. In the subsequent cultivation phase, one unit used luffa pads while the other used cellulose pads. The conditions recommended from the pre-experimental phase—water flow rate of 4.2 L/min, fan air velocity of 1.3 m/s, and a setpoint temperature of 28 °C were applied. During cultivation, the average indoor relative humidity was 85.41% for the luffa unit and 76.13% for the cellulose unit. The dry bulb temperature ranged from 25.23 °C to 32.23 °C (average 25.89 °C) for the luffa pad, and from 26.13 °C to 34.99 °C (average 26.0 °C) for the cellulose pad, over the three 10-day production stages (a, b, and c). The average saturation efficiency was 72.67% for the luffa pad and 64.16% for the cellulose pad.