Improvement of a rubber drying greenhouse with a parabolic cover and enhanced panels

• PGEP was built to improve efficiency by using extra polycarbonate panels.
• The inside temperature of empty PGEP was 5 °C higher compared to the PG’s.
• PGEP also took shorter time to dry rubber sheets on the experiment.
• The model simulated the internal temperatures of empty PG and PGEP.
• The model simulated the reduction rate of moisture content of rubber sheets.

Two structures of a greenhouse for rubber drying: (1) parabolic greenhouse (PG) and (2) parabolic greenhouse with the additional area-enhanced panels (PGEP) have been designed and built in this work. The experiment was divided into two parts: (1) a test of the empty greenhouses; and (2) a test of the greenhouses with rubber sheets drying. The results from the first part revealed that the measured air temperature within the PGEP was 5 °C higher than PG’s. The new-designed PGEP provides higher thermal efficiency than the PG. Mathematical model was utilized to predict the air temperatures inside the empty greenhouses and the results agreed well with the experimental data. In addition, the test of greenhouses with rubber sheets drying showed that the drying period in PGEP was only 1.5 days while the drying period in PG was up to 5 days. The rubber sheets dried with this method were classified as grade 1 (the top quality) and there was no fungal growth found in the sheets. The finite difference was applied in the mathematical model to predict the reduction of moisture content of the rubber sheets. The results from the model agreed well with the results from the experiments. Other significant parameters were also discussed.

According to the simulation for the internal temperatures of PGEP and PG at the same ambient and solar intensity, the efficiency of the new-designed PGEP is 5–10 °C higher. Rubber sheet drying experiment of both PGEP and PG shows higher quality of the sheets comparing to the traditional method of local farmers and PGEP took fifty percent less time as well.Figure optionsDownload as PowerPoint slide