Table 1.
Container‐specific characteristics of the boxes and tubs
| Parameter | Boxes | Tubs |
|---|---|---|
| Container outer dimensions (L × W × H) | 80 × 45 × 27 cma | 120 × 100 × 79 cmb |
| Container inner dimensions (L × W × H) | 62 × 37 × 23 cma | 111–115 × 91–95 × 60.5–61.5 cmc |
| Container thickness | 0.5 cm | 4.6 cm |
| Container material | HDPEc | Triple‐walled with a PE structure of the outer walls and PE core of the container (3.6 cm PE foam core in between 0.5 cm HDPE skin)c , d |
| Container weight | 4.18 kga | 55 kgb |
| Container volume | 60 La | 630 Lb |
| Fish added in the container | 30 kge | 440 kgf |
| Ice added in the container | 15 kg (for ‘keeping’ and ‘cooling‐keeping’ processes)e | 38 kg (‘keeping’ process) and 63 kg (‘cooling‐keeping’ process)f |
| Water added in tubs | NA | 100 kg (‘keeping’ process) and 100 kg (‘cooling‐keeping’ process)f |
| Type of water used | NA | Freshwater without salt added |
| Type of ice and arrangement | Top and bottom layers of ice | Water with ice on top |
HDPE: high‐density polyethylene; NA: not applicable; PE: polyethylene.
Based on the ‘180° fish box ‐ 800 × 450 × 270 mm ‐ solid base and walls ‐ 2 open handholes’.10
Based on the ‘Seaplast 630 Insulated Storage Bulk Container’.11
Considered having following properties (as of PE skin): thermal conductivity of 0.44 W/(m·°C), density of 930 kg/m3 and heat capacity of 1.64 kJ/(kg·°C) at constant pressure.
Considered having following properties (as of PE foam of the core of the container): thermal conductivity of 0.05 W/(m·°C), density of 70 kg/m3 and heat capacity of 2.3 kJ/(kg·°C) at constant pressure.
Considered having following properties: thermal conductivity of 0.035 W/(m·°C), density of 31 kg/m3 and heat capacity of 1.28 kJ/(kg·°C) at constant pressure.
For boxes, the amount of fish and ice considered the practice applied in the ‘Qualitubfish’ project (Bekaert et al., 2016a,b) and relied on the ice/fish ratio of 1/2 according to (Graham et al., 1992). Smaller quantities of ice with respect to fish have been also reported (Thordarson et al., 2017; Laguerre et al., 2019), which may lead to an earlier need of re‐icing to ensure the presence of ice in the container.
For tubs, the amount of fish and water was based on the practice applied in the ‘Qualitubfish’ project (Bekaert et al., 2016a,b), while the amount of ice was estimated through the ice calculator for tubs that can be retrieved at https://isreiknir.matisprojects.com/ (Ragnarsson, 2017). Convection on both sides of the wall was not considered and it assumed that the container is closed and is similar to 660 L‐PE. The calculations were made to ensure ice was not completely melted when the tub would be stored for 7 days at 2°C (with safety margin of 2 days). It assumed an initial fish and water temperature of 0°C and 3°C, respectively, for the ‘keeping’ process. It assumed an initial fish and water temperature of 7°C and 0.5°C, respectively, for the ‘cooling‐keeping’ process.