Annual Performance of a Modified Greenhouse Dryer Under Passive Mode In No-Load Conditions

摘要

A detail study of thermal performance for modified greenhouse dryer under passive mode in no-load conditions is being conducted from January 2013 to May 2013. This provides a complete study of the thermal performance of the dryer. The experiments were conducted during sunshine hours of the day at the Energy Centre, Maulana Azad National Institute of Technology (MANIT), Bhopal (23.5 degrees N, 77.42 degrees E), India from 15th to 17th of the each month. The dryer was designed and constructed with the concept of opaque north wall. The thermal performance of this dryer was presented with change of different floor conditions, namely barren floor, floor covered with black PVC sheet, and black-painted floor. It has been observed that presently designed and modified solar greenhouse dryer with floor covered with black PVC sheet shows superior performance than other two floor conditions. Various thermal parameters - heat loss, coefficient of diffusion, heat transfer coefficients, and dimensionless numbers, namely Nusselt, Grashof, Prandtl, and Rayleigh numbers, were calculated based on the experimental data. The characteristic curve was developed for all three conditions. It intercepted at zero and had R-2 = 0.99. The embodied energy for this dryer was found to be 480.2776 kWh. The total uncertainty was found to be 0.0891.