Articles
A TUNNEL GREENHOUSE ADAPTED TO THE TROPICAL LOWLAND CLIMATE
Until then, the few shelters in production where "classic tunnels" : (plastic cover burried on the sides, without gable ends). It rappidly made no doubt that it was inadequate.
The inside diurnal temperatures raised too high for most vegetables.
Through the world none satisfying commercial and technical solution appeared to our exigencies :
- a simple shelter structure to protect the plants from the heavy diverted rains.
- a particularly performant aeration, specially for the humid lowland tropics.
- a low cost (investment and functioning) with a view towards the development and the extension of the protected crops in these areas.
Since 1965 in french Guyana, successfull vegetables productions under shelters are conducted.
I.R.A.T. had developped a very performant woodden framed structure two span plastic greenhouse.
Because of the lack of wood in Martinique and the frequency of intense cyclones, this technology could not be spread.
In a first phase we decided to compare the performances in regard to the temperatures of :
- a classic "umbrella tunnel".
- a two-span steel framed greenhouse.
- a completely closed tunnel with dynamic ventilation.
Then on a second phase, we oriented our studies towards the adaptation of the tunnel for an optimal natural ventilation through two commercial prototypes.
At the issue of this work, we are now in position to propose a simple and efficace solution to the thermic exigencies under plastic greenhouse in the lowland tropics, this "tropical tunnel" is a chimney effect tunnel with a natural and static aeration favoured by continued low and top openings.
Under the ridge opening, a transparent plastic gutter is disposed to collect the rain.