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Application of a tracer aerosol technique using atomized sodium chloride particles for measuring ventilation rates in a naturally ventilated Azrom-type greenhouse in Zimbabwe

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Abstract
In this study ventilation rates for a naturally ventilated Azrom type greenhouse in Zimbabwe were determined by both a tracer aerosol technique using atomized NaCl particles as the tracer and an integrating nephelometer to monitor the decay of the aerosol particles’ concentration in the greenhouse and the water vapour balance method. Comparison of the results showed that, although the tracer aerosol method suffers from some of the typical problems of tracer techniques in general (like the need for uniform concentration of the tracer), it gave comparable results with the water vapour balance method, while overcoming the difficulty of the water vapour balance of scaling up from single (or few) plant(s) to whole canopy transpiration. The M903 Radiance Research portable nephelometer is a lightweight, low-power instrument, and costs about US,000, while the nebulizer costs less than US,000. In comparison with the high cost of gas analyzers (up to US,000 for most CO2 and N2O analyzers) and the additional high costs and unavailability of the tracers, the method offers a cost-effective way of measuring ventilation rates in a greenhouse. For measuring leakage ventilation rates, however, the tracer aerosol technique failed to provide useful results.
Keywords
Ventilation rate, Climate control, Ventilation, Water Vapour Balance Method, Tracer Aerosol Technique, Greenhouses, CONTINUOUS ROOF VENTS, INSECT SCREENS, SIDE OPENINGS, MICROCLIMATE, FLOW, TRANSPIRATION, NEPHELOMETER, SENSITIVITY, BALANCE, PLANTS

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Chicago
Mashonjowa, Emmanuel, Frederik Ronsse, Dorcas Nhiwatiwa, Frans Meixner, James Milford, Raoul Lemeur, and Jan Pieters. 2010. “Application of a Tracer Aerosol Technique Using Atomized Sodium Chloride Particles for Measuring Ventilation Rates in a Naturally Ventilated Azrom-type Greenhouse in Zimbabwe.” Applied Engineering in Agriculture 26 (2): 275–286.
APA
Mashonjowa, E., Ronsse, F., Nhiwatiwa, D., Meixner, F., Milford, J., Lemeur, R., & Pieters, J. (2010). Application of a tracer aerosol technique using atomized sodium chloride particles for measuring ventilation rates in a naturally ventilated Azrom-type greenhouse in Zimbabwe. APPLIED ENGINEERING IN AGRICULTURE, 26(2), 275–286.
Vancouver
1.
Mashonjowa E, Ronsse F, Nhiwatiwa D, Meixner F, Milford J, Lemeur R, et al. Application of a tracer aerosol technique using atomized sodium chloride particles for measuring ventilation rates in a naturally ventilated Azrom-type greenhouse in Zimbabwe. APPLIED ENGINEERING IN AGRICULTURE. 2010;26(2):275–86.
MLA
Mashonjowa, Emmanuel, Frederik Ronsse, Dorcas Nhiwatiwa, et al. “Application of a Tracer Aerosol Technique Using Atomized Sodium Chloride Particles for Measuring Ventilation Rates in a Naturally Ventilated Azrom-type Greenhouse in Zimbabwe.” APPLIED ENGINEERING IN AGRICULTURE 26.2 (2010): 275–286. Print.
@article{819778,
  abstract     = {In this study ventilation rates for a naturally ventilated Azrom type greenhouse in Zimbabwe were determined by both a tracer aerosol technique using atomized NaCl particles as the tracer and an integrating nephelometer to monitor the decay of the aerosol particles{\textquoteright} concentration in the greenhouse and the water vapour balance method. Comparison of the results showed that, although the tracer aerosol method suffers from some of the typical problems of tracer techniques in general (like the need for uniform concentration of the tracer), it gave comparable results with the water vapour balance method, while overcoming the difficulty of the water vapour balance of scaling up from single (or few) plant(s) to whole canopy transpiration. The M903 Radiance Research portable nephelometer is a lightweight, low-power instrument, and costs about US,000, while the nebulizer costs less than US,000. In comparison with the high cost of gas analyzers (up to US,000 for most CO2 and N2O analyzers) and the additional high costs and unavailability of the tracers, the method offers a cost-effective way of measuring ventilation rates in a greenhouse. For measuring leakage ventilation rates, however, the tracer aerosol technique failed to provide useful results.},
  author       = {Mashonjowa, Emmanuel and Ronsse, Frederik and Nhiwatiwa, Dorcas and Meixner, Frans and Milford, James and Lemeur, Raoul and Pieters, Jan},
  issn         = {0883-8542},
  journal      = {APPLIED ENGINEERING IN AGRICULTURE},
  keyword      = {Ventilation rate,Climate control,Ventilation,Water Vapour Balance Method,Tracer Aerosol Technique,Greenhouses,CONTINUOUS ROOF VENTS,INSECT SCREENS,SIDE OPENINGS,MICROCLIMATE,FLOW,TRANSPIRATION,NEPHELOMETER,SENSITIVITY,BALANCE,PLANTS},
  language     = {eng},
  number       = {2},
  pages        = {275--286},
  title        = {Application of a tracer aerosol technique using atomized sodium chloride particles for measuring ventilation rates in a naturally ventilated Azrom-type greenhouse in Zimbabwe},
  volume       = {26},
  year         = {2010},
}

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