Advanced search
2 files | 4.18 MB

Measurement and simulation of the ventilation rates in a naturally ventilated Azrom type greenhouse in Zimbabwe

Emmanuel Mashonjowa (UGent) , Frederik Ronsse (UGent) , James Milford, Raoul Lemeur (UGent) and Jan Pieters (UGent)
Author
Organization
Abstract
A simple greenhouse ventilation model, based on the stack and wind effects (the main driving forces for natural ventilation) was adapted, calibrated and validated using measured air renewal rates in a three span naturally ventilated Azrom type greenhouse in Zimbabwe. Crop transpiration rates were monitored using stem heat balance sap flow gauges installed on the main stems of rose plants to continuously monitor whole-plant transpiration (WPT). This allowed continuous and automatic determination of full scale air renewal and leakage rates using the water vapour balance method. The model was fitted to experimental data of ventilation rates, and discharge and wind effect coefficients were determined. The results show a good fit between measured and predicted values (R2 = 0.80 and 0.82 for winter and summer, respectively), although there is a general over-estimation of the greenhouse air renewal rates, particularly during the night. The model, nevertheless, adequately describes the natural ventilation process in the greenhouse all year round. The model can be used as a design tool to evaluate and optimise the effects of different ventilation configurations and strategies on greenhouse air renewal rates, and as a component in a greenhouse climate model in order to further evaluate the effects of ventilation strategies on the inside greenhouse and crop microclimate, and thus lead to better greenhouse climate control.
Keywords
HEAT-BALANCE METHOD, CONTINUOUS ROOF VENTS, FLOW MEASUREMENTS, SIDE OPENINGS, SAP FLOW, TRANSPIRATION, MICROCLIMATE, ROSE, WIND, SCREENS, Climate control, Climate model, Greenhouses, Ventilation, Ventilation rate, Ventilation model

Downloads

  • (...).pdf
    • full text
    • |
    • UGent only
    • |
    • PDF
    • |
    • 1.93 MB
  • Mashonjowa2010b biblio authorversion.pdf
    • full text
    • |
    • open access
    • |
    • PDF
    • |
    • 2.25 MB

Citation

Please use this url to cite or link to this publication:

Chicago
Mashonjowa, Emmanuel, Frederik Ronsse, James Milford, Raoul Lemeur, and Jan Pieters. 2010. “Measurement and Simulation of the Ventilation Rates in a Naturally Ventilated Azrom Type Greenhouse in Zimbabwe.” Applied Engineering in Agriculture 26 (3): 475–488.
APA
Mashonjowa, E., Ronsse, F., Milford, J., Lemeur, R., & Pieters, J. (2010). Measurement and simulation of the ventilation rates in a naturally ventilated Azrom type greenhouse in Zimbabwe. APPLIED ENGINEERING IN AGRICULTURE, 26(3), 475–488.
Vancouver
1.
Mashonjowa E, Ronsse F, Milford J, Lemeur R, Pieters J. Measurement and simulation of the ventilation rates in a naturally ventilated Azrom type greenhouse in Zimbabwe. APPLIED ENGINEERING IN AGRICULTURE. 2010;26(3):475–88.
MLA
Mashonjowa, Emmanuel et al. “Measurement and Simulation of the Ventilation Rates in a Naturally Ventilated Azrom Type Greenhouse in Zimbabwe.” APPLIED ENGINEERING IN AGRICULTURE 26.3 (2010): 475–488. Print.
@article{831181,
  abstract     = {A simple greenhouse ventilation model, based on the stack and wind effects (the main driving forces for natural ventilation) was adapted, calibrated and validated using measured air renewal rates in a three span naturally ventilated Azrom type greenhouse in Zimbabwe. Crop transpiration rates were monitored using stem heat balance sap flow gauges installed on the main stems of rose plants to continuously monitor whole-plant transpiration (WPT). This allowed continuous and automatic determination of full scale air renewal and leakage rates using the water vapour balance method. The model was fitted to experimental data of ventilation rates, and discharge and wind effect coefficients were determined. The results show a good fit between measured and predicted values (R2 = 0.80 and 0.82 for winter and summer, respectively), although there is a general over-estimation of the greenhouse air renewal rates, particularly during the night. The model, nevertheless, adequately describes the natural ventilation process in the greenhouse all year round. The model can be used as a design tool to evaluate and optimise the effects of different ventilation configurations and strategies on greenhouse air renewal rates, and as a component in a greenhouse climate model in order to further evaluate the effects of ventilation strategies on the inside greenhouse and crop microclimate, and thus lead to better greenhouse climate control.},
  author       = {Mashonjowa, Emmanuel and Ronsse, Frederik and Milford, James and Lemeur, Raoul and Pieters, Jan},
  issn         = {0883-8542},
  journal      = {APPLIED ENGINEERING IN AGRICULTURE},
  keywords     = {HEAT-BALANCE METHOD,CONTINUOUS ROOF VENTS,FLOW MEASUREMENTS,SIDE OPENINGS,SAP FLOW,TRANSPIRATION,MICROCLIMATE,ROSE,WIND,SCREENS,Climate control,Climate model,Greenhouses,Ventilation,Ventilation rate,Ventilation model},
  language     = {eng},
  number       = {3},
  pages        = {475--488},
  title        = {Measurement and simulation of the ventilation rates in a naturally ventilated Azrom type greenhouse in Zimbabwe},
  volume       = {26},
  year         = {2010},
}

Web of Science
Times cited: