NUMERICAL AND EXPERIMENTAL ANALYSIS OF HEAT AND MASS TRANSFER FOR A PASSIVE SOLAR GREENHOUSE

The passive solar greenhouse is one of the effective ways of solar thermal applications, which involves periodical solar radiation, coupled heat and mass transfer, ventilation, transpiration of plants and other physical and/or biological factors. The heat and mass transfer mechanism is, therefore, rather complicated and must be treated, on the whole, as a transient transfer process. This paper establishes a three dimensional transient heat and mass transfer model for a passive solar greenhouse with compacted soil walls, which is widely used in the north of China. Taking into account some necessary boundary conditions which are changing with time, such as the outside air temperature, solar radiation, and wind parameters, the temperature and relative humidity distribution of the indoor air is numerically obtained by means of the software CFD. The temperature and relative humidity test of the passive solar greenhouse was also conducted for comparison. The results indicate that the predicted temperature and relative humidity of the indoor air were in a good agreement with the experimental data, with a maximum temperature absolute error of +/- 0.54 degrees C. and a maximum relative humidity absolute error of +/- 1.25%, and both of the temperature and relative humidity obtained a general average fitting error under 1%. The hourly indoor air temperature in this case study was found to be over 12 degrees C, which is suitable for the growth of warm-season plants.