Investigations on energy recovery capability of coconut oil for pre-cooling of apples from cold storage condensate

Abstract

Assessment in a live cold storage plant revealed that the refrigeration process generated about 150–170 L of condensate per day at 10 °C–12 °C. In this study, phase change property of coconut oil was applied to recover and use the energy from condensate for pre-cooling apples. Charging studies of coconut oil was carried out experimentally and the charging time was found to be 234, 126, 95 and 93 min for condensate flow rates of 2.6 L/h, 4.25 L/h, 6.26 L/h and 8.33 L/h respectively. Discharging studies were conducted for natural and forced convection for pre-cooling of apples under two cases namely apples in direct contact (case i) and indirect contact (case ii) with the container. Under natural convection and direct contact, pre-cooling of 4 °C was achieved with a discharge duration of 260 min. In case (ii), pre-cooling of 3.5 °C was achieved with discharge duration of 304 min. Likewise, under forced convection, pre-cooling of 3.5 °C was achieved in 189 min for case (i) and 214 min for case (ii). Temperature difference between the top point and bottom point of the apple was 1.5 °C and 0.5 °C for case (i) and case (ii) respectively. Results confirmed that coconut oil as a PCM can be used for recovering energy from condensate for pre-cooling of apples before loading into a cold storage unit.