Development of a sustainable methodology for life-cycle performance evaluation of solar dryers

An innovative methodology for the performance evaluation of solar dryers, which considers the total life-cycle (LC) energy effectiveness in present-value terms, has been proposed. In this method, the performance of solar dryers has been defined in terms of a set of performance parameters, called present value performance indicators (PVPIs). By applying the concept of unsteady-state mass and energy balances for solar kilns, and using known diffusion and heat transport equations from drying theory, a mathematical model was constructed and subsequently solved to predict the future thermal energy inflows and outflows as part of the assessment of the performance parameters. In order to illustrate the overall methodology proposed in this study, the model has been applied, as an example, to a case-study greenhouse-type solar kiln (i.e. Oxford) in the context of hardwood drying in Australia. The current methods used for the performance evaluation of solar dryers have also been reviewed, and it was found that the proposed method was likely to overcome the shortcomings and inadequacies of the current practices for assessing the performance of solar dryers. A sensitivity analysis was carried out in order to assess the robustness of the estimated performance indicators against the uncertain parameters.