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Energies 2014, 7(3), 1427-1447; doi:10.3390/en7031427
Article

Energy Efficiency in Greenhouse Evaporative Cooling Techniques: Cooling Boxes versus Cellulose Pads

1
, 2,*  and 2
Received: 17 December 2013; in revised form: 20 February 2014 / Accepted: 3 March 2014 / Published: 7 March 2014
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Abstract: Evaporative cooling systems using a combination of evaporative pads and extractor fans require greenhouses to be hermetic. The greatest concentration of greenhouses in the world is located in southeast Spain, but these tend not to be hermetic structures and consequently can only rely on fogging systems as evaporative cooling techniques. Evaporative cooling boxes provide an alternative to such systems. Using a low-speed wind tunnel, the present work has compared the performance of this system with four pads of differing geometry and thickness manufactured by two different companies. The results obtained show that the plastic packing in the cooling unit produces a pressure drop of 11.05 Pa at 2 m·s−1, which is between 51.27% and 94.87% lower than that produced by the 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 also had 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-hermetic greenhouses such as those most frequently used in the Mediterranean basin.
Keywords: greenhouse; evaporative cooling; pressure drop; heat and mass transfer coefficients; specific water consumption; saturation efficiency greenhouse; evaporative cooling; pressure drop; heat and mass transfer coefficients; specific water consumption; saturation efficiency
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Franco, A.; Valera, D.L.; Peña, A. Energy Efficiency in Greenhouse Evaporative Cooling Techniques: Cooling Boxes versus Cellulose Pads. Energies 2014, 7, 1427-1447.

AMA Style

Franco A, Valera DL, Peña A. Energy Efficiency in Greenhouse Evaporative Cooling Techniques: Cooling Boxes versus Cellulose Pads. Energies. 2014; 7(3):1427-1447.

Chicago/Turabian Style

Franco, Antonio; Valera, Diego L.; Peña, Araceli. 2014. "Energy Efficiency in Greenhouse Evaporative Cooling Techniques: Cooling Boxes versus Cellulose Pads." Energies 7, no. 3: 1427-1447.


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