AIRFLOW AND TEMPERATURE DISTRIBUTION IN GREENHOUSES WITH FAN VENTILATION

J.S. Wolfe, R.F. Cotton
Observations of air flow in glasshouses with exhaust-fan ventilation have shown that the pattern of flow is not a uniformly deep stream moving directly from inlet to fans, but is more complex and largely determined by the configuration of the inlet and to some extent by that of the roof. A crop or other resistance to flow in the house also influences the flow pattern. Detailed flow patterns have been determined for a number of inlet configurations, both without a crop in the house and with different heights of crop. The implications of air-flow patterns for temperature distribution are discussed.

Temperature measurements have been made in greenhouses and greenhouse compartments with exhaust-fan ventilation. Temperature rise from inlet to fans is linearly related to solar radiation intensity. The experimental value differed from that calculated from theory by different amounts at different radiation levels, and it has not yet been possible to explain this. Temperature does not rise linearly between inlet and fans, and was higher at or above the top of the crop canopy than within it in a full-size house but not in a glasshouse compartment. An explanation for this contrast has not yet been found.

Wolfe, J.S. and Cotton, R.F. (1975). AIRFLOW AND TEMPERATURE DISTRIBUTION IN GREENHOUSES WITH FAN VENTILATION. Acta Hortic. 46, 71-90
DOI: 10.17660/ActaHortic.1975.46.7
https://doi.org/10.17660/ActaHortic.1975.46.7