Evaluation of Energy Efficiency in a Grain Unloading Platform

Abstract

This paper aims to conduct an energy efficiency study in the tipping system of the unloading platform of a grain storage unit, based on the use of electrical devices to control the operation of the engine. For this purpose, two scenarios were established. The first scenario considers the platform in its current state, with engine start-up performed using a wye-delta switch. In the second scenario, wye-delta start is switched off, and a frequency inverter and a programmable logic controller (PLC) are coupled to control the electric motor. For both scenarios, the consumption of active and reactive energy in the discharge platform was measured, and the costs of the energy consumed were calculated over a period of one year. Finally, the discounted payback was calculated to evaluate the economic feasibility of installing the proposed equipment. The results obtained were as follows: For the current scenario, the energy consumed to tipping one metric ton of grain was 35.44.10-3 kWh; for the proposed scenario with the frequency inverter, the energy was 32.78.10-3 kWh. With an annual projection, the current scenario would consume the equivalent of 10 921.35 kWh, and the proposed scenario, 10 100.81 kWh, generating an annual savings, with the installation of the equipment, of R$721.49; the discounted payback found was approximately 31 years. It can thus be concluded that there is a reduction in electricity consumption from the use of the frequency inverter; however, the time of return of the invested capital is very long, making the proposal economically unfeasible.