Observatorio de I+D+i UPM

Memorias de investigación
Research Publications in journals:
Cooling Strategies for Greenhouses in Summer: Control of Fogging by Pulse Width Modulation
Year:2008
Research Areas
  • Agriculture
Information
Abstract
The objective of the paper was to study the possibilities of improving the control of greenhouse fog systems, by comparing several combinations of ventilation cooling techniques, shade screening and low-pressure fogging. The study was divided into three parts: experimental testing, modelling and simulations. In the first part of the paper, ten combinations of five cooling techniques were tested (summer 2002 and 2003) in a 132 m2 greenhouse with a steel structure and a single-layer methacrylate cover located in Madrid (Spain). An analysis of variance of the climate parameters was carried out to determine which combinations produced significant differences of inside temperature or relative humidity. Comparing the values for the inside to outside temperature difference, the combination of shade screen and above-screen fogging achieved a difference in temperature almost the same as for under-screen fogging, but the relative humidity was significantly lower. In the second part of the study a dynamic model was fitted (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 1.5ºC 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% to 15% with respect to the strategies with a fixed fogging cycle.
International
Si
JCR
Si
Title
BIOSYSTEMS ENGINEERING
ISBN
1537-5110
Impact factor JCR
0,862
Impact info
Volume
4
10.1016/j.biosystemseng.2008.01.001
Journal number
99
From page
573
To page
586
Month
ENERO
Ranking
Participants
  • Autor: Jose Luis Garcia Fernandez (UPM)
  • Autor: Alicia Perdigones Borderias (UPM)
  • Autor: Cecilia Raposo Llobet (UPM)
  • Autor: Luis Luna Sanchez (UPM)
  • Autor: Saturnino de la Plaza Perez (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Energía y Agricultura
  • Departamento: Ingeniería Rural
S2i 2019 Observatorio de investigación @ UPM con la colaboración del Consejo Social UPM
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