Design and Electro-Thermal Evaluation of a Solar PV-Integrated Ohmic Heating System for Kiwi Juice Pasteurization

• Hawri Sweed Ahmed1*, Ibrahim Yuosef Essa2

  Author

A factorial design experiment was used to evaluate the electrothermal performance of an ohmic heater using photovoltaic energy for pasteurization of kiwi juice. The ohmic heater was designed to run in controlled conditions using solar cells connected to a hybrid inverter with a lithium-ion battery unit for stable electrical power supply. To achieve this, an acrylic heating chamber covered with transparent cover sheets was fabricated and equipped with stainless-steel electrodes. The fresh kiwi juice was processed at six levels of applied voltage; 30, 45, 60, 75, 90 and 105 V with processing times of 30-105 seconds. Electrothermal performance was evaluated in terms of changes in temperature, current, pH, electrical conductivity, and total dissolved solids which were measured and statistically analyzed. Increase in applied voltage and processing time led to high significance (P≤ 0.01) in temperature rise, current intensity, EC and TDS. The highest temperature and current attained were 66.7oC and 2.20 A respectively. There was also a great increase in EC from 4252 to 5510 µS/cm and TDS from 2141 to 2472 ppm. However, pH changed slightly within the range 3.70-3.80. The observed changes might have been associated with ion movement in juice and/or changes in permeability of cell membranes during ohmic heating.

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