ISHS Acta Horticulturae 245: Engineering and Economic Aspects of Energy Saving in Protected Cultivation
TRANSIENT TEMPERATURE FIELD IN THE HEATED SOIL OF A GREENHOUSE |
| Authors: | A. Silva, R. Rosa |
| Abstract:
Water heated by means of a water-water heat pump was stored in a 5 m3 reservoir, from where it was made to circulate continuously through a subsurface pipe grid. Two classic models of heat conduction in a solid were used to describe the transient field temperature in the soil after power switch on and for about ten days till a nearly steady state regime was attained. On the basis of these models, temperature measurements allowed the heat conductivity and heat diffusivity of the soil to be determined, as well as the coefficient of heat transfer from the surface to the atmosphere. The results were: 0.64< respectively for conductivity, diffusivity and coefficient of surface heat transfer of a sandy loam soil between dry bare and wet cultivated situation. These results are found in fairly good agreement with values given in the literature for a similar soil in similar circumstances. | |
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