Impact of a solar greenhouse converted into a solar dryer on the performance indicators (energy efficiency, bio-chemical, economic and environmental) during summer season

Abstract

To maximize the use of a solar greenhouse and conserve energy or material consumption during all seasons, this study explores the feasibility of transforming an agricultural solar greenhouse into a solar dryer during the summer season. The system features an original solar heating system, combining a copper tube positioned between the double-glazed roof and a sensitive heat storage system installed inside the greenhouse. This new solar dryer consists of a solar collector on the roof, a drying chamber, and a thermal storage system. During the day, the hot air produced by the greenhouse effect will be evacuated to the attached compartment to dry the various products offered.

This article presents an assessment of the thermal performance of the greenhouse dryer with a comparison to two other indirect solar dryers. The internal temperature in the new indirect solar dryer is 53.11 °C when the ambient air temperature is 25.42 °C. However, the thermal efficiency of the new indirect solar dryer is recorded at 22.95 %. The payback period is 0.41 years for the new solar dryer, 1.62 years for solar dryer 2 and 7.28 years for solar dryer 1. Concerning the environmental analysis of the new solar dryer, the embodied energy is determined at 5006.09 kWh and for the time required for the energy payback is approximately 5.60 years, as long as the annual ${\mathrm{CO}}_2$ emissions is 511.12 kg/year. Over its lifetime, the new solar dryer can mitigate up to 26.29 tons of ${\mathrm{CO}}_2$ and the total gained carbon credit is $525.84.