Forced-air cooling of polylined horticultural produce: Optimal cooling conditions and package design

Abstract A 3-D computational fluid dynamics (CFD) model of palletised polylined kiwifruit packages undergoing forced-air cooling was used to determine an optimal operating point. Two operating conditions (pressure drop and flowrate across the pallet) were tested and the results evaluated based on cooling rate, uniformity, energy requirement and pallet throughput per week. An optimal operating point of 100 Pa (0.25 L kg −1  s −1 ) ensured relatively rapid cooling of the produce, without incurring excessive operational costs due to the energy requirements. Based on the results an alternative package was designed with the aim of redistributing the incoming refrigerated airflow to channel cool air through the pallet layers before directing it towards the slowest cooling packages, located at the back of the pallet. Evaluating the new design at the optimal conditions for the current package showed that at constant flowrate both pressure drop and energy requirement to achieve half-cooling time (HCT) were reduced by 24%, while improving cooling uniformity and pallet throughput per week. Alternatively, keeping the pressure drop constant required a similar energy input, while further increasing the cooling uniformity and pallet throughput.

[1]  Bart Nicolai,et al.  Combined discrete element and CFD modelling of airflow through random stacking of horticultural products in vented boxes , 2008 .

[2]  Bart Nicolai,et al.  MODELLING TURBULENT AIR FLOW IN COOL ROOMS FOR HORTICULTURAL PRODUCTS , 2003 .

[3]  Clément Vigneault,et al.  Maximum slat width for cooling efficiency of horticultural produce in wooden crates , 2006 .

[4]  Andrew R. East,et al.  Airflow measurement techniques for the improvement of forced-air cooling, refrigeration and drying operations , 2014 .

[5]  R.G.M. van der Sman.  Prediction of airflow through a vented box by the Darcy–Forchheimer equation , 2002 .

[6]  Martine Baelmans,et al.  CFD model of the airflow, heat and mass transfer in cool stores , 2005 .

[7]  Jochen Mellmann,et al.  Studying airflow and heat transfer characteristics of a horticultural produce packaging system using a 3-D CFD model. Part I: Model development and validation , 2013 .

[8]  Jalal Dehghannya,et al.  Mathematical Modeling Procedures for Airflow, Heat and Mass Transfer During Forced Convection Cooling of Produce: A Review , 2010 .

[9]  R. P. Singh,et al.  Modeling the forced-air cooling process of fresh strawberry packages, Part II: Experimental validation of the flow model , 2009 .

[10]  Thijs Defraeye,et al.  Forced-convective cooling of citrus fruit: package design , 2013 .

[11]  M. Ferrua,et al.  Performance of the forced-air cooling process of fruit packed in polyethylene liners as a function of pallet orientation. , 2013 .

[12]  Jalal Dehghannya,et al.  Mathematical modeling of airflow and heat transfer during forced convection cooling of produce considering various package vent areas , 2011 .

[13]  N. Lallu,et al.  Kiwifruit ( Actinidia spp.) , 2011 .

[14]  R. P. Singh,et al.  Modeling the forced-air cooling process of fresh strawberry packages, Part I: Numerical model , 2009 .

[15]  Clément Vigneault,et al.  Container opening design for horticultural produce cooling efficiency , 2004 .

[16]  Umezuruike Linus Opara,et al.  Investigating the Effects of Table Grape Package Components and Stacking on Airflow, Heat and Mass Transfer Using 3-D CFD Modelling , 2012, Food and Bioprocess Technology.

[17]  Bart Nicolai,et al.  Modelling the forced-air cooling mechanisms and performance of polylined horticultural produce , 2016 .

[18]  Jochen Mellmann,et al.  Studying airflow and heat transfer characteristics of a horticultural produce packaging system using a 3-D CFD model. Part II: Effect of package design , 2013 .

[19]  Jalal Dehghannya,et al.  Transport phenomena modelling during produce cooling for optimal package design: Thermal sensitivity analysis , 2012 .

[20]  M. V. Krishna Murthy,et al.  Forced-air precooling of spherical foods in bulk: A parametric study , 1997 .

[21]  P. Roache.  QUANTIFICATION OF UNCERTAINTY IN COMPUTATIONAL FLUID DYNAMICS , 1997 .

[22]  Tadhg Brosnan,et al.  Precooling techniques and applications for horticultural products — a review , 2001 .

[23]  Clément Vigneault,et al.  EFFECT OF CONTAINER OPENING AREA ON AIR DISTRIBUTION DURING PRECOOLING Of HORTICULTURAL PRODUCE , 2004 .

[24]  Jalal Dehghannya,et al.  Simultaneous Aerodynamic and Thermal Analysis during Cooling of Stacked Spheres inside Ventilated Packages , 2008 .

[25]  Clément Vigneault,et al.  Design of Packaging Vents for Cooling Fresh Horticultural Produce , 2012, Food and Bioprocess Technology.

[26]  Thijs Defraeye,et al.  Forced-convective cooling of citrus fruit: Cooling conditions and energy consumption in relation to package design , 2014 .

[27]  R. P. Singh,et al.  Improved airflow method and packaging system for forced-air cooling of strawberries , 2011 .