A Study of Extraction and Accumulation of the Heat Generated in Composting Process: Part 2. A Theoretical Analysis of Heat Extraction and Accumulation Process by Water Circulation

摘要

A theoretical analysis of an operation of extraction and accumulation of the heat generated in composting process by water circulation was made. The calculated results of the average temperature in a compost bed and the water temperature in an accumulator were compared with the experimental results obtained previously.1) For the case of the intermittent water-circulation, there were slight differences between the calculated results and the experimental results of the average temperature in the bed during temperature recovering periods after the end of water-circulation. However, the calculated results of the water temperature in the accumulator, the available time for heat extraction and the recovery time of temperature in the bed agreed relatively well with the experimental results. The theoretical model was fairly fit for this case.2) For the case of the continuous water-circulation, the calculated results of the average temperature in the bed were in fair agreement with the experimental results. The calculated results of the water temperature in the accumulator were however 3 to 7 degrees higher than the experimental results. It could be due to the heat loss through the pipes connecting the container for the compost with the accumulator, which was not allowed for in the theoretical model. It is necessary to modify the analytical model by taking account of this kind of heat loss.