Estimation of local ventilation efficiency by using optical method: Measuring local numbers of ventilation in the environmental controlled greenhouse of fruit trees
2008
Hoshi, N.(National Agricultural Research Center for Western Region, Zentsuji, Kagawa (Japan). Shikoku Research Center) | Hiraoka, K. | Shimazaki, M. | Morinaga, K. | Kuroyanagi, T.
A technique using an aerosol and optical sensors was introduced to estimate local ventilation efficiency in the environmental controlled glasshouse of fruit trees. After filling aerosol as optical tracer, instead of the tracer-gas like CO2, and mechanically ventilating in the glasshouse, laser beam is irradiated to the evaluating areas of the glasshouse and the increasing curve of laser signals according to the attenuation of aerosol content is measured to estimate the local numbers of ventilation in the glasshouse. The number of ventilation calculated from the exhaust air flow rate was 30.3/hr. On the other hand, the values of local number of ventilation measured by the method were ranged from 1.05 to 39.6/hr. This is shown that there are clear dispersions in local numbers of ventilation which mean non-homogeneous condition in the glasshouse. The performance of ventilation system would be evaluated by using the optical method, especially when the ventilation rate is low.
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