Optimisation of multi-scale ventilated package design for next-generation cold chain strategies of horticulture produce
| dc.contributor.advisor | Coetzee, Corne | en_ZA |
| dc.contributor.advisor | Opara, Umezuruike Linus | en_ZA |
| dc.contributor.author | Berry, Tarl Michael | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. | en_ZA |
| dc.date.accessioned | 2017-02-21T09:48:23Z | |
| dc.date.accessioned | 2017-03-29T12:10:10Z | |
| dc.date.available | 2017-02-21T09:48:23Z | |
| dc.date.available | 2017-03-29T12:10:10Z | |
| dc.date.issued | 2017-03 | |
| dc.description | Thesis (PhD)--Stellenbosch University, 2017. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Corrugated fibreboard boxes (cartons) are used extensively in the cold chain to transport fresh produce from growers to consumers. These ventilated packaging systems have multi-scale structures and should facilitate suitable cooling of produce to preserve quality, protect against mechanical damage and enable efficient handling and transport. However, current designs often do not incorporate these factors and improved designs have been identified as part of new strategies to reduce postharvest losses and enhance overall cold chain efficiency. The aim of this thesis was to develop improved fresh produce packaging designs through the use of a novel multi-parameter evaluation approach, within the scope of a multi-scaled packaging system. To this end, computational fluid dynamics (CFD) models and experimental box compression tests were used to evaluate new packaging designs, to quantify spatio-temporal moisture distributions in cartons during shipping and to increase packing densities in refrigerated freight containers (RFC). Three new vent hole configurations were proposed and compared against an existing carton used for handling pome fruit. Results showed that the presence of trays reduced cooling efficiency by 31% in the standard commercial design. Conversely, the use of the newly proposed vent designs considerably improved both cooling efficiency and cooling uniformity by 48% and 79%, respectively. Next, the effect of vent hole area and board material was investigated. Results demonstrated that significant improvements in both cooling efficiency and carton strength are possible, using alternative vent hole designs. Additionally, a significant interaction, with respect to mechanical strength, was observed between board material properties (board type) and the vent hole design. This finding indicates that high humidity conditions (i.e. refrigerated transport) can substantially influence the expected mode of failure in cartons (mechanical performance). Furthermore, a CFD model was developed to predict spatio-temporal moisture distribution in cartons loaded in a RFC. The study of a standard shipping scenario showed that moisture gradients were relatively small, indicating that mechano-sorptive creep is likely not a major factor in this case. However, larger gradients are expected during less desirable conditions. These findings can be used as baseline conditioning treatments for future carton compression protocols. Lastly, two unique packaging system strategies were proposed and evaluated for cooling efficiency. Although both showed generally improved performance, the “Tes” design increased packing density by 12% and forced-air cooling efficiency by 29%, compared to standard designs. Findings also showed improvements in vent hole design for vertical flow (RFC) are still possible. Overall, research reported in this thesis contributes towards the development of a more optimal ventilated packaging design for use in the fresh produce cold chain. Significant advancements were also made with respect to the implementation of a multi-parameter evaluation approach, which should be further extended to future assessments of fresh produce supply chains both in academia and in commercial practice. Finally, significant knowledge gaps were revealed with respect to the mechanical performance of cartons under high humidity conditions. Future studies should therefore concentrate on the development of new predictive approaches to better assess the integrated performance of cartons under cold chain conditions. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Geriffelde veselbord bokse (kartonne) word op groot skaal in die koue ketting gebruik om varsprodukte te vervoer vanaf produsente na verbruikers. Geventileerde verpakkingstelsels het multi-skaal strukture en moet geskikte verkoeling van die produkte fasiliteer om gehalte te bewaar, die produkte te beskerm teen meganiese beskadiging en doeltreffende hantering en vervoer van die produkte in staat te stel. Huidige ontwerpe neem egter dikwels nie hierdie faktore in ag nie en verbeterde ontwerpe is geïdentifiseer as deel van nuwe strategieë om na-oes verliese te verminder en die algehele koue ketting doeltreffendheid te verbeter. Die doel van hierdie tesis was om verbeterde verpakkingsontwerpe te ontwikkel deur die gebruik van 'n unieke multi-parameter benadering. Vir hierdie doel, is berekeningsvloeidinamika (BVD) modelle en eksperimentele boks druktoetse gebruik om nuwe verpakkingsontwerpe te evalueer, tydruimtelike vog verspreidings in bokse te kwantifiseer tydens vervoer en verpakkingsdigthede in verkoelde vraghouers (VVH) te verhoog. Drie nuwe ventilasie gatkonfigurasies is voorgestel en vergelyk teen 'n bestaande boksontwerp. Resultate het getoon dat die teenwoordigheid van rakkies die doeltreffendheid van verkoeling in die standaard kommersiële ontwerp verminder met 31%. Aan die ander kant, het die gebruik van die nuwe voorgestelde ontwerpe verkoelingsdoeltreffendheid en verkoelingseenvormigheid onderskeidelik verbeter met 48% en 79%. Die effek van ventilasie gat area en boks materiaal is ondersoek. Resultate het getoon dat beduidende verbeterings in beide verkoelingsdoeltreffendheid en bokssterkte moontlik is, deur alternatiewe ventilasie gat ontwerpe te gebruik. Daarbenewens is 'n beduidende interaksie, met betrekking tot meganiese sterkte, waargeneem tussen boks materiaal eienskappe en die ventilasie gat ontwerp. Hierdie bevinding dui daarop dat hoë lugvog toestande die verwagte wyse van meganiese faling in bokse aansienlik kan beïnvloed. Verder is 'n BVD model ontwikkel om tydruimtelike voginhoud verspreidings te voorspel binne kartonne wat verpak is in 'n VVH. Die studie van 'n standaard verskeping scenario het getoon dat vog gradiënte relatief klein was, wat daarop aandui dat megano-sorptiewe kruip waarskynlik nie 'n belangrike faktor in hierdie geval is nie. Tog is groter gradiënte tydens minder wenslike toestande verwag. Hierdie bevindinge kan gebruik word as 'n basislyn kondisionering behandeling vir toekomstige boks druktoets protokolle. Laastens, is twee unieke verpakkingstelsel strategieë voorgestel en geëvalueer vir verkoelingsdoeltreffendheid. Alhoewel beide oor die algemeen goeie resultate getoon het, het die "Tes" ontwerp in vergelyking met die standaard ontwerpe, die verpakkingsdigtheid met 12% en gevorseerde lugverkoelingsdoeltreffendheid met 29% verhoog. Bevindinge het getoon dat verbeterings in ventilasie gat ontwerp vir vertikale vloei steeds moontlik is. Algehele navorsing berig in hierdie tesis dra by tot die ontwikkeling van 'n meer optimale ontwerp vir gebruik in die varsprodukte koue ketting. Beduidende vooruitgang is gemaak met betrekking tot die implementering van 'n multi-parameter evaluering benadering, wat verder uitgebrei moet word tot toekomstige assessering van varsprodukte voorsieningskettings beide in die akademie en kommersiëel. Ten slotte, is groot leemtes in bestaande kennis geïdentifiseer met betrekking tot die meganiese verrigting van bokse onder toestande van hoë humiditeit. Toekomstige studies behoort dus te konsentreer op die ontwikkeling van nuwe voorspellende benaderings om die geïntegreerde werkverrigting van bokse beter onder koue ketting toestande te evalueer. | af_ZA |
| dc.format.extent | 201 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/101117 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Corrugated board -- design | en_ZA |
| dc.subject | Refrigerated container | en_ZA |
| dc.subject | Packaging -- Design | en_ZA |
| dc.subject | Computational fluid dynamics | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.subject | Cartons -- Manufacturing processes | en_ZA |
| dc.title | Optimisation of multi-scale ventilated package design for next-generation cold chain strategies of horticulture produce | en_ZA |
| dc.type | Thesis | en_ZA |