Articles
THE CONTROL OF TEMPERATURE, HUMIDITY AND CARBON DIOXIDE CONCENTRATION IN EXPERIMENTAL GLASSHOUSES
Article number
174_59
Pages
443 – 448
Language
Abstract
A set of five experimental glasshouses was equipped with systems for controlling temperature, humidity and carbon dioxide concentration for the purpose of research into the microclimatology of tropical crops.
As the desired air temperature inside the glasshouses was usually above the ambient temperature, there was little need for cooling apart from that provided by natural and fan-assisted ventilation.
Heating by gas-fired hot-blown air provided a fast response and precise control of air temperature.
Humidity was increased by a spinning disk humidifier and decreased by ventilation.
Both air temperature and humidity oscillated diurnally to simulate the changes in these variables in the plants’ natural environment.
Carbon dioxide was injected to maintain its concentration inside the glasshouse similar to that outside, a system of control that also enabled computation of the net rate of assimilation of carbon dioxide by the stand within a glasshouse.
There was no attempt to increase the level of light beyond that received from natural daylight.
As the desired air temperature inside the glasshouses was usually above the ambient temperature, there was little need for cooling apart from that provided by natural and fan-assisted ventilation.
Heating by gas-fired hot-blown air provided a fast response and precise control of air temperature.
Humidity was increased by a spinning disk humidifier and decreased by ventilation.
Both air temperature and humidity oscillated diurnally to simulate the changes in these variables in the plants’ natural environment.
Carbon dioxide was injected to maintain its concentration inside the glasshouse similar to that outside, a system of control that also enabled computation of the net rate of assimilation of carbon dioxide by the stand within a glasshouse.
There was no attempt to increase the level of light beyond that received from natural daylight.
Publication
Authors
R.A. Saffell
Keywords
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