Cooling Strategies for Greenhouses in Summer: Control of Fogging by Pulse Width Modulation

Perdigones Borderias, Alicia and García Fernández, José Luis and Romero, Alicia and Rodriguez, Alejandro and Luna Sánchez, Luis and Raposo Llobet, Cecilia and Plaza Pérez, Saturnino de (2008). Cooling Strategies for Greenhouses in Summer: Control of Fogging by Pulse Width Modulation. "Biosystems Engineering", v. 99 (n. 4); pp. 573-586. ISSN 1537-5110. https://doi.org/10.1016/j.biosystemseng.2008.01.001.

Description

Title: Cooling Strategies for Greenhouses in Summer: Control of Fogging by Pulse Width Modulation
Author/s:
  • Perdigones Borderias, Alicia
  • García Fernández, José Luis
  • Romero, Alicia
  • Rodriguez, Alejandro
  • Luna Sánchez, Luis
  • Raposo Llobet, Cecilia
  • Plaza Pérez, Saturnino de
Item Type: Article
Título de Revista/Publicación: Biosystems Engineering
Date: April 2008
ISSN: 1537-5110
Volume: 99
Subjects:
Faculty: E.T.S.I. Agrónomos (UPM) [antigua denominación]
Department: Ingeniería Rural [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

The possibilities for improving the control of greenhouse fogging systems, were studied by comparing several combinations of ventilation cooling techniques, shade screening and low-pressure fogging. The study was divided into three parts: experiments, modelling and simulations. In the first part of the paper, ten combinations of five cooling techniques were tested during the summers of 2002 and 2003 in a 132m2 greenhouse with a steel structure and a single-layer methacrylate cover located in Madrid, Spain. An analysis of variance of the climatic parameters was carried out to determine which combinations produced significant differences in inside temperature or relative humidity. Comparing the values for the inside to outside temperature difference, the combination of a shade screen and above-screen fogging achieved a difference in temperature almost the same as that for under-screen fogging, but the relative humidity was significantly lower. In the second part of the study a dynamic model was developed (2002) and validated (2003). The mean absolute error obtained for inside temperature was similar in the fit and the validation and it was less than 1.5 1C in both cases. The model was used to simulate the inside air temperature for a fog system working without shading, and above and under a shade screen. Control algorithms were developed for reducing system water consumption. In the three cases a simple on/off control with a fixed fogging cycle was compared with a pulse width modulation (PWM) strategy, in which the duration of the fogging pulse was increased as a function of inside temperature. The strategies with PWM applied to the fog system were able to reduce water consumption by 8–15% with respect to the strategies with a fixed fogging cycle.

More information

Item ID: 2563
DC Identifier: http://oa.upm.es/2563/
OAI Identifier: oai:oa.upm.es:2563
DOI: 10.1016/j.biosystemseng.2008.01.001
Official URL: http://www.sciencedirect.com/science?_ob=PublicationURL&_cdi=7168&_pubType=J&_acct=C000047350&_version=1&_urlVersion=0&_userid=885385&md5=62e912848b3c597c01013cf9adec61ae&jchunk=99#99
Deposited by: Memoria Investigacion
Deposited on: 13 Apr 2010 09:39
Last Modified: 20 Apr 2016 12:13
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