Evaporative cooling systems using a combination of evaporative pads andextractor fans require greenhouses to be hermetic. The greatest concentration of greenhousesin the world is located in southeast Spain, but these tend not to be hermetic structures andconsequently can only rely on fogging systems as evaporative cooling techniques.Evaporative cooling boxes provide an alternative to such systems. Using a low-speed windtunnel, the present work has compared the performance of this system with four padsof differing geometry and thickness manufactured by two different companies. Theresults obtained show that the plastic packing in the cooling unit produces a pressure dropof 11.05 Pa at 2 m·s−1, which is between 51.27% and 94.87% lower than that produced bythe cellulose pads. This pressure drop was not influenced by increases in the water flow.The evaporative cooling boxes presented greater saturation efficiency at the same flow,namely 82.63%, as opposed to an average figure of 65% for the cellulose pads; and alsohad a lower specific consumption of water, at around 3.05 L·h−1·m−2·°C−1. Consequently,we conclude that evaporative cooling boxes are a good option for cooling non-hermeticgreenhouses such as those most frequently used in the Mediterranean basin.
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