Abstract
This paper deals with the problem of heat and mass transfer in the process of composting experiments which were done by ventilating the air from the bottom through deep layer of excrement of livestock or poultry. A computed estimation method for the process of this system was presented. Data of air temperature and material temperture in each layer were used to estimate the dry matter and water decreases. It was supposed that the ventilating air was always saturated, and that the sum of apparent heat rises of air and material and latent heat of vaporization was equal to the amount of heat produced by aerobic fermentation. After the heat leak from the wall was compensated, calculated and experimented values became so close that the computed estimation method was considered to be reliable. With this method, it became possible to know the characteristics of aerobic fermentation and drying process in detail as to the lapse of time such as decrease of dry matter, aerobic fermentation rate and moisture content.
