PACKAGING FOR SEA FREIGHT - Cool Chaincoolchain.org/Websites/cca/Images/CCA Workshop SA 2010... ·...

••••Faculty of AgriSciences

Umezuruike Linus Opara

SA Research Chair in Postharvest Technology

PACKAGING FOR SEA

FREIGHT

Umezuruike Linus Opara

SA Research Chair in Postharvest Technology

A view from inside-out of ventilated packaging

Packaging for the cold chain

What is a Cold Chain?

*A logistics *A logistics processprocess where where temperaturetemperature--sensitivesensitive

cargo will maintain its integrity through multicargo will maintain its integrity through multi--modal modal

movementmovement and kept in ambient and kept in ambient facilitiesfacilities to ensure to ensure

100% quality, freshness, and customer satisfaction.100% quality, freshness, and customer satisfaction.

TransLogistique TransLogistique Canada. Canada. Conference Conference –– Fairmont Hotel Dubai Fairmont Hotel Dubai ––

October 12 / 13, 2004. www.translogistique.orgOctober 12 / 13, 2004. www.translogistique.org

Sticky gecko feet: The role of temperature and humidity

• In 2008, a team of University of Akron/USA researchers published a paper which tested the effect of temperature and humidity on the ability of geckos to stick to glass

• Under very humid conditions, geckos stick with twice the force compared to dry conditions at low temperatures.

• At high temperatures, geckos stick comparatively poorly and the humidity level is less important. http://www.plos.org/

Role of packaging in the cold chain

WHAT DOES FRUIT AND BEER HAVE IN COMMON?

VENTILATED PACKAGING!

Sometimes small changechange in package can make a big impact

Coors Brewing Company Vented Wide

Mouth™ can.

The real innovation here: not the wide-mouth

opening, but the "vent" that is part of the

opening.

Slightly raised portion of the opening allows

for better airflow when drinking – enhancing

"gulp-ability" – long, smooth drinking motion.

More in the pourMore in the pourMore in the pourMore in the pour

Fruit Container Net weight (kg)

Oranges Fiberboard carton

Fiberboard box

Carton for place packing

20

39

17–18

Tangerines/ mandarins/hybrids

Fiberboard carton

Fiberboard carton

Master carton with 10 bags of 1.3 to 1.4 kg

Master carton with 16 bags of 1.4 kg

20

11-12

13–13.5

22

Grapefruit Fiberboard carton (28.9 lit)

Fiberboard carton



19

17–18

22

24

Limes Small carton

Fiberboard carton (28.9 lit)

4.5

17-18

Lemons Fiberboard carton (28.9 lit) 17

Containers Generally Used for Fresh Citrus in the U.S.A.

What Package? Which Package? Whose Package?

Packaging,Costs, Value and Postharvest Losses

Contribution of Individual Postharvest Operations

(Total=60.82%)

6.97

8.74

18.95

21.16

0

4

8

12

16

20

24

Storage Harvesting Marketing+Transport Grading+Packing

Co

ntr

ibu

tio

n t

o P

os

tha

rve

st

Co

st

(%)

Cost of a Unit Weight of Apple Fruit

(Source: UK Grower, Wk 37, 1994)

12

Data from Mr Reinhardt Reingruh,

SOURCE (2010)

Economic Develo

pment

Grains Meat, Fish and Dairy

Valu

e-ad

din

g

Fruit & Vegetables

threshing

packaging

cold storage

CA storageMAP

transport:

truck, ship, rail

airfreight

Relationship between Postharvest Technology Relationship between Postharvest Technology Relationship between Postharvest Technology Relationship between Postharvest Technology and Economic Developmentand Economic Developmentand Economic Developmentand Economic Development

Perishables-orientedDurables-oriented

Farming-

oriented

Business-

oriented

drying

milling

baking

brewing

fermentationstorage

freezing

pickling

Freeze-drying

Minimal processing,

ready-to-eat

industrial food

manufacturing

health-foods

hurdle technologies

Packaging adds 20% to cost of fruit

• Based on recent supermarket survey in the UK

• Environment minister Ben Bradshaw urged shoppers to boycott heavily packaged fruit and boycott heavily packaged fruit and

vegetablesvegetables in order to pressure supermarkets to be more environmentally friendly

N. Cecil & E. Widdup, Evening Standard, 18 April 2007

http/www.thisismoney.co.uk/consumer/

Postharvest Losses and Waste

• 30-50% food postharvest losses and wastage in many less developed countries

• 2-3% food wastage in developed countries

• Less than 1% of packed 1% of packed food goes to waste, compared with 1010--20% of unpacked food20% of unpacked food

• A Tetra Pak motto is that a package should save a package should save

more than its costsmore than its costs

Table grapes packaging loss

(a) Weight loss from shipping to retail market

under near optimal postharvest handling ~2%.

(b) Weight loss from shipping to retail market

under sub-optimal postharvest handling

conditions (e.g. delays, higher °C, lower RH) ~7%.

(c) The 5% weight loss + low appearance quality

= 15% loss in value and returns

Package Handling Environment

• Climate

• High/low temperature, moisture, relative humidity, loght, gases, volatile, dust

• Physical/mechanical

• Shocks, compression, puncture, vibration, abrasion, tearing, racking

• Biochemical

• Microbes – bacteria, fungi, moulds, yeasts, viruses

• Pests – rodents, insects, mites, birds

Table: Effect of ventilation level in packaging material on

fruit weight loss of peach under ambient conditions.

Ventilation level Weight loss (%) after days

1 2 3 4 5

0 % 0.1 0.3 0.5 0.8 1.0

2.5% 2.5 4.7 6.2 8.7 10.6

5% 3.2 7.4 9.8 12.6 -

7.5% 3.7 8.3 11.4 15.1 -

Control Control 5.7 5.7 16.8 16.8 24.6 24.6 34.6 34.6 --

General Considerations

1) Total vent area <25% of package surface

restricts airflow significantly

2) Vent area <10% results in lower cooling

rate and higher cooling costs

3) Vent area >8% did not increase cooling

rate significantly

Background to Packaging Cold Chain Modelling Research

• Tanner, D.J., Cleland, A.C., Robertson, T.R., Opara, L.U., 2000. Use of CO2 as a trace gas for determining in-package airflow distribution. Journal of Agricultural Engineering Research 77(4): 409-417.

• Tanner, D.J., A.C. Cleland, L.U. Opara, T.R. Robertson. 2002. A generalised mathematical modelling methodology for design of horticultural food packages exposed to refrigerated conditions: Part 1, formulation. International Journal of Refrigeration, 25(1): 33-42.

• Tanner, D.J., A.C. Cleland, L.U. Opara, T.R. Robertson. 2002. A generalised mathematical modelling methodology for design of horticultural food packages exposed to refrigerated conditions: Part 2. Heat transfer modelling and testing. International Journal of Refrigeration, 25(1): 43-53.

Cold Chain Modelling-Computational Fluid Dynamics Modelling

• Problem Definition

• Numerical Model Development

• Software Development

• Sensitivity Analysis

• Model Testing

• Conclusions

Functions of Packaging (3CP)

•Containment

•Communication

•Convenience

•Protection

Fruit Packaging & Protection: A Complex Problem

The Problem : Therm odynam ic D esign of F ruit PackagingThe Problem : Therm odynam ic D esign of F ruit PackagingThe Problem : Therm odynam ic D esign of F ruit PackagingThe Problem : Therm odynam ic D esign of F ruit Packaging

Fruit Packaging&

Cooling Problem



Critical success factors:

•Vent designdesign

••placementplacement of produce

Consequences of bad packaging

•Non-uniform cooling

•Inadequate cooling rate

0

5

10

15

20

25

30

0 5 10 15

Time

Fru

it t

em

pera

ture

No ventilation

Ventilated

Features of the System to be Modelled

Features Descriptions

Domains •Individual package

•Stack of packages

Package types •Bulk package

•Layered package

Transport

processes

•Air mass transfer

•Air momentum transfer

•Heat transfer

•Moisture transfer

Boundary

conditions

•On one side of stack or individual package, airflow

leaves or enters vents with fixed velocity

•On the other sides, airflow pressure on the vents is

equal to that of the surrounding environment

•If airflow enters a vent, it has fixed temperature equal

to the cooling temperature

Overall Modeling Strategy

Moisture transfer models

simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model

CFD methods

solving

moisture loss model




simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss



simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD methods

solving

moisture loss model


simulating

weight/water loss

CFD Models of Airflow Pattern &

Heat Transfer Inside Bulk and Layered Packages

Regions in bulk and layered packages

Illustration of the porous media approach for a layered package

Global grid systems for the domains of a single package and a layer of packages.

Illustration of grid generation processes for a layered package (grid generation for x-z plane of a layered package).

Journal of Food Engineering, Vol. 77, 2005, pp.1037–1047

A CFD modeling system for airflow and heattransfer in ventilated packaging for fresh foods: I. initial analysis and development of mathematical models

Zou, Q., Opara, L.U. and McKibbin, R.

CFD Models of Airflow Pattern Inside Bulk Packages (1)

Continuity equation for air mass conservation in vents

Air mass conservation in the produce-air regions

Air momentum conservation in the plain air regions (vents).

( ) ( ) ( ) 0=∂

+∂

+aaa

wz

vy

ux

φ∂φ∂φ∂∂

0=dx

du0=

dy

dv

dx

dp

dx

du

dx

d

dx

duua −=

− µρ

dy

dp

dy

dv

dy

d

dy

dvva −=

− µρ

Air momentum conservation in the produce-air regions (generalised volume average momentum equation)

( ) ( ) ( )

( )aaaa

aaa

aaa

aaaaaaaaa

uwvuK

F

K

u

x

p

z

u

zy

u

yx

u

x

uwz

uvy

uux

2

1222

32

)( ++−−−

=

∂∂

∂∂−

∂∂

∂∂−

∂∂

∂∂−

++

ρφµφ∂

φ∂

µφµφµφ

φρ∂∂φρ

∂∂φρ

∂∂

( ) ( ) ( )

( )aaaa

aaa

aaa

aaaaaaaaa

vwvuK

F

K

v

y

p

z

v

zy

v

yx

v

x

vwz

vvy

vux

2

1222

32

)( ++−−−

=

∂∂

∂∂−

∂∂

∂∂−

∂∂

∂∂−

++

ρφµφ∂

φ∂

µφµφµφ

φρ∂∂φρ

∂∂φρ

∂∂

( ) ( ) ( )

( )aaaa

aaa

aaa

aaaaaaaaa

wwvuK

F

K

w

z

p

z

w

zy

w

yx

w

x

wwz

wvy

wux

2

1222

32

)( ++−−−

=

∂∂

∂∂−

∂∂

∂∂−

∂∂

∂∂−

++

ρφµφ∂

φ∂

µφµφµφ

φρ∂∂φρ

∂∂φρ

∂∂


Auxiliary algebraic equations in the produce-air regions

Porosity near a package wall, φφφφ

Permeability, K

Forchheimer coefficient, F

Equivalent mean diameter of produce items, deq

)1( eqd

by

ae−

∞ += φφ

2

32

)1( φφ

−=

A

dK

eq

3φA

BF =

p

p

eqS

Vd 6=


CFD Models of Heat Transfer

Air energy conservation equation in vents

Energy conservation equation in the solid region

Volume-averaged air energy equation in the produce-air regions

Volume-averaged product energy equation in the produce-air regions

Energy conservation equation in single produce items

Auxiliary algebraic equations

Solution of systems of discretisation equations

• The solution of the systems of discretisation equations followed the SIMPLER procedure (Patankar, 1980).

• GMRES (Generalised Minimum Residual) iterative method was employed to solve the systems of algebraic equations in each inner iteration step (Kelley, 1995).

• The solvers were written in C language.

• Java interface was employed to integrate the solvers with the other model components.

• Users interact with the software via three components: • System Designer

• Solution Monitor

• Visualization Tool.

Journal of Food Engineering, Vol. 77, 2005, pp.1048–1058

A CFD modeling system for airflow and heat transfer in ventilated packaging for fresh foods: II. computational solution, software development and model testing

Zou, Q., Opara, L.U. and McKibbin, R.

Model Testing

Model Testing

Results of Model Testing

Int. J. Postharvest Technology and Innovation, Vol. 1, No. 2, 2006, 155-169

Novel computational fluid dynamics simulation software for

thermal design and evaluation of horticultural packaging

Linus U. Opara*Postharvest Technology Research Programme and Agricultural

Experiment Station, College of Agricultural and Marine Sciences,

Sultan Qaboos University, Al-Khod, Sultanate of Oman

E-mail: [email protected] *Corresponding author

Qian ZouFood Systems and Technology,

AgResearch Limited,

Ruakura MIRINZ Centre,

Hamilton, New Zealand

E-mail: [email protected]

Keywords: computational fluid dynamics; horticultural produce;

innovation; packaging; thermal design.

Copyright © 2006 Inderscience Enterprises Ltd.

Components of ‘CoolSimu’ simulation software

CoolSimu: A User-friendly software

International Journal of Food

Engineering

Volume 3, Issue 5 2007 Article 16

Sensitivity Analysis of a CFD Modelling

System for Airflow and Heat Transfer of Fresh

Food Packaging: Inlet Air Flow Velocity and

Inside-Package Configurations

Linus U. Opara Qian Zou†

KEYWORDS: CFD modeling, airflow, heat transfer, ventilated packaging, fruit

temperature, sensitivity analysis

Copyright ©2007 The Berkeley Electronic Press. All rights reserved.

Sensitivity Analysis

4-Layered Cardboard Package

Variations in vent area (±±±± 20% change on both back and front walls)

• Variations in the vent area did not have significant effect on model predictions in the near-inlet regions, but had noticeable influence in the package centre and near-outlet regions (areas can be easily measured to the required accuracy)

Positions

Predicted product centre temperature

(K) for the specified vent areas Temperature difference (K)

400 mm2 320 mm2 480 mm2 320-400 mm2 480 -400 mm2

Cell (1, 3, 1) 276.65 277.35 276.00 0.70 -0.65

Cell (3, 3, 1) 284.66 286.06 283.34 1.40 -1.32

Cell (3, 1, 1) 281.22 282.71 280.26 1.49 -0.96

Cell (5, 3, 1) 287.19 288.07 286.28 0.88 -0.91

Cell (1, 3, 2) 274.36 274.69 274.07 0.33 -0.29

Cell (3, 3, 2) 281.47 282.33 280.20 0.86 -1.27

Average 279.62 280.61 278.77 0.99 -0.85

Variations in vent position on the carton(lowering the positions of the vents on both back and

front walls by 30mm)

Positions

Predicted product centre temperature (K) for

the specified vent positionsTemperature

difference

(K) Base case 30mm lower

Cell (1, 3, 1) 276.65 275.66 -0.99

Cell (3, 3, 1) 284.66 281.67 -2.99

Cell (3, 1, 1) 281.22 279.89 -1.33

Cell (5, 3, 1) 287.19 285.26 -1.93

Cell (1, 3, 2) 274.36 273.10 -1.26

Cell (3, 3, 2) 281.47 277.40 -4.07

Cell (3, 1, 2) 279.34 278.11 -1.23

Cell (5, 3, 2) 286.50 282.90 -3.60

Variations in vent position on the carton(lowering the positions of the vents on both back and

front walls by 30mm)

• Vent position significantly affected model predictions, as it alters the distribution of airflow among the produce layers, and consequently affects the heat transfer between air and produce items.

Cell (3, 3, 4) 279.08 281.81 2.73

Cell (3, 1, 4) 278.09 280.17 2.08

Cell (5, 3, 4) 282.92 285.11 2.19

Positions

Predicted product centre temperature (K) for

the specified vent positionsTemperature

difference (K) Base case 30mm lower

Airflow and heat transfer inside ventilated packaging

containing six tray layers of fruit: CFD simulation results

and experimental validation

Linus U. Opara Qian Zou

Keywords: CFD; Airflow; Heat transfer; Forced-air cooling; Fruit trays;

Simulation; Model validation; Flow visualization; Tray layers

Simulation of Fruit Cooling Inside 6-Layered Cardboard Package

Predicted airflow pattern and pressure distribution on the top (6th) produce layer XY surface, Z=6) inside a 'Standard' 6-layer apple carton

Predicted airflow pattern and pressure distribution in the bottom (1st) produce layer (XY surface, Z=1) inside a 'Standard' 6-layer apple carton

Predicted airflow pattern and pressure distribution in the 5th produce layer (XY surface, Z=5) inside a 'Standard' 6-layer apple carton

Predicted air and produce temperature profile in the top (6th) produce layer (XY surface, Z=6) in a 'Standard' 6-layer apple carton after 1 hour of cooling.

Predicted air and produce temperature profile in the 5th

produce layer (XY surface, Z=5) in a 'Standard' 6-layer apple carton after 1 hour of cooling

Predicted air and produce temperature profile in the bottom (1st) produce layer (XY surface, Z=1) in a 'Standard' 6-layer apple carton after 1 hour of cooling

Temperature profiles in the centre of produce items in the top (6th) layer

Temperature profiles in the centre of produce items in the 5th layer (nearest to the vent)

Conclusions

• Airflow patterns and heat transfer processes inside layered and bulk packaging for fresh produce are complex

• We developed and tested a CFD model for predicting the thermal performance inside such complex packaging systems

Conclusions

• Extensive model testing gave fairly good and consistent agreement with experimental data on product cooling rates

• In all carton layers, the model slightly under-predicted the cooling rates of the produce items located

• along package sidewalls and

• in the middle of the carton

Conclusions

Sensitivity analysis of model predictions:

• Changes in vent size (area) did not significantly affect model predictions in the near-inlet regions, but had noticeable influence in the package centre and near-outlet regions;

• Vent position significantly affected model predictions;

• Model predictions were very sensitive to variation in the width of air gaps between trays and package walls.

TH A N K TH A N K TH A N K TH A N K Y O U !Y O U !Y O U !Y O U !

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