Articles
SEMIBURIED GREENHOUSES, DYNAMIC SIMULATION OF THE PROCESSES OF HEAT AND MASS TRANSFER
The main characteristic of the semiburied greenhouse is that they differ from the conventional ones in that all their walls are part of the soil, enhancing, its regulating effect.
Because of this, the greenhouse’s walls play the same role as the floor during the energy balance.
A semiburied greenhouse makes use not only of the thermal properties of the soil but also protects the entire system from the prevailing winds, adding in this way a positive factor to the energy balance as well as reducing significantly the mechanical damage risk.
The developed model is based on the following basic hypothesis: -The greenhouse is considered as a system of layers. -The soil is treated in a bidimensional way and is related to the rest of the system by an average value. -It is assumed that all the layers are homogeneous, except for the soil. -Boundary primary conditions are considered. -The thermal and optical properties do not vary during the simulation.
In order to compare the thermal efficiency of a semiburied greenhouse with a conventional one, a simulation with the same outside conditions of a conventional chapel shaped greenhouse was carried out, using a previously developed and tested model.
The results obtained showed the advantages of the greenhouse discussed in this paper that, at critical moments, present higher temperatures than the conventional greenhouse (from 4 to 6 C).