ANALYSIS OF GREENHOUSES HEATED BY UNDERGROUND PIPES

An analysis is made of a greenhouse which is heated by means of air circulating through horizontal pipes buried below the surface of the ground in the greenhouse and thus extracting heat from the ground.

The heating system is based on the fact that at depths the ground -and even below the greenhouse- the temperature is relatively constant in time and the energy which may be extracted daily from the soil is sufficient to cover the heating requirements of greenhouses in temperate zones.

The greenhouse is simulated by joining together two systems, the first consisting of a one-dimensional dynamic model of the greenhouse, Levit and Gaspar (1988), the second of a two-dimensional model of the pipes, Puri (1986). In both cases only primary conditions and heat and mass transfer processes are considered, whilst the conductive thermal flow between them is not considered.

Thermal and economic analyses are given for a typical greenhouse in the Argentine "Humid Pampa" and the results obtained for different temperature requirements and diverse operating strategies are presented.

Finally, representative curves which may be used in the pre-design of similar system are included.

Symposium on High Technology in Protected Cultivation

H.J. Levit, R. Gaspar

https://doi.org/10.17660/ActaHortic.1988.230.71