Energy and exergy analysis of greenhouse drying of ivy gourd and turkey berry

Abstract

Original scientific paper https://doi.org/10.2298/TSCI190602459SThis study deals with the performance evaluation of a simple low-cost greenhouse dryer using energy and exergy analysis. Drying experiments were conducted under the open Sun and in greenhouse dryer with two different cover sheets of ultra violet polyethylene and drip lock under passive mode and active mode for two vegetables with medicinal values: ivy gourd (coccinia grandis) and turkey berry (solanum torvum). Thermal efficiency, exergy efficiency, and improvement potential were evaluated and presented. The experiment showed that performance of the greenhouse dryer was better than the open sun drying. Thermal efficiencies were up to 30.64% and exergy efficiency values were up to 0.09% and the maximum values were obtained during the drying of ivy gourd with the drip lock sheet under active mode. The results showed that this dryer could be used for drying agricultural products at low cost by the farmers in order to produce value added products from their harvested products.Drying or dehydration of food products decreases the moisture in the products to reduce weight, for easy transportation and increase shelf life. Traditionally agricultural products have been dried under the open Sun. It is a simple and economic process but has a lot of disadvantages, like depending on weather, slow process, loss due to birds, dust and other contamination. Best quality of dried products can be achieved with industrial hot air dryers, but it requires a huge amount of energy. Approximately 9.25% of the available energy in the developed countries is being consumed by drying process [3]. So, new cost and energy effective systems are essential to reduce the energy consumption. The objective of a drying system is to supply more heat to the product than available in the ambient [4]. It needs a proper thermodynamic analysis of a drying system.Energy and exergy analysis using First and Second law of thermodynamics should be performed for finding out the energy interactions and thermodynamic behavior of a drying system [5]. The analysis of a dryer should provide a quantitative measure of inefficiencies for a designer to design better systems [6]. The exergy analysis delivers suitable information to select the appropriate design and operational procedure for better performance [7].Exergy is the maximum work attained from a stream of matter, heat or work as it comes to equilibrium with a reference environment [8]. By carrying out exergy accounting in smaller and smaller subsystems, we are able to draw a map of how the destruction of exergy is scattered over the engineering system [9]. The lesser thermal efficiency of drying systems, higher price of fossil fuel and electricity and the GHG emitted from drying systems increase the importance for exergy analysis of drying systems [10]. Various exergetic indicators used in food industry are absolute exergy loss, exergetic efficiency, improvement potential, exergy destruction ratio, entropy generation, and cumulative exergy loss. Grass...

Convective and evaporative heat transfer coefficients during drying of ivy gourd under natural and forced convection solar dryer

“…It was observed that the convective heat transfer coefficients of dried three products, namely gurjo, Turmeric and Ginger, were varied from 1.57-3.85, 2.32-3.42 and 1.62-3.34W/m 2 °C. Subramani et al (2020) fabricated the natural and forced convection greenhouse solar dryer for drying two different samples, namely ivy gourd and turkey berry. It was determined that the thermal efficiency of the greenhouse dryer found to be 30.6%.…”

Mathematical modeling of thin layer drying characteristics and proximate analysis of Turkey berry (Solanum torvum)

“…The experiments were conducted for drying turkey berry under open sun drying, UV polyethylene as glazing material, drip lock sheet as glazing matrial under passive and active mode [21] .The following conclusions were drawn from the results obtained.…”

Energy and Exergy Analysis of an Indirect-Mode Natural Convection Solar Dryer for Maize

“…The average exergy efficiencies are 2.4 % and 2.6 % for the 10 kg and 5 kg loads respectively, and are lower than the energy efficiencies. Tiwari, Des, Chen and Barnwel (2009) in the greenhouse drying of fish, and Subramani, Dana, Natesan, and Leo (2020) in the greenhouse drying of ivy gourd and turkey berry, also found that the exergy efficiency was lower than the energy efficiency and attributed this to some of the input exergy being destroyed due to irreversibility.…”