PSI - Issue 77

Arian Semedo and João Garcia/ Structural Integrity Procedia 00 (2026) 000–000

3

Arian Semedo et al. / Procedia Structural Integrity 77 (2026) 498–511

500

Q̇c= (T 1 − T 2 R ) [w]

(1)

Q̇c − Thermal load from conduction (W) T 1 − Internal temperature (ºC) T 2 − External temperature (ºC) R − Thermal resistance of the wall (ºC/W)

The temperature difference between the product inserted into the chamber and the ambient air temperature within the chamber is represented by equation (2), which expresses the amount of heat introduced by the product due to its entry into the refrigerated spaces (Pereira and Oliveira (2020)).

Q̇p=ṁ rot . C P (T in − T 1 ) [W]

(2)

Q̇p − Thermal load from product (W) C P − Specific heat of the product before freezing (J/ (kg ∙K)) T in − Product inlet temperature (ºC) ṁ rot . − Product flow into the cold chamber (kg/s)

The occupants, equipment, and lighting within the refrigerated space constitute three separate heat sources, as shown in equation (3) (Hashim et al (2018)). Heat generated by human metabolism results in both sensible and latent heat, owing to the temperature and humidity differences between the human body and the air inside the chamber. In contrast, heat emitted by lighting and operational devices in the space contributes exclusively to sensible heat. Q̇i − Internal thermal load (W) Q̇o − Thermal loads from occupants (W) Q̇l − Thermal loads from lighting (W) Q̇e − Thermal loads from equipment (W) The air infiltrations from the exterior into the interior of the refrigeration chamber, through the door, are responsible for the thermal loads resulting from these infiltrations, as described by equation (4) (Bak, Koo,Yoon and Lim (2022)). Q̇inf − Thermal load from infiltrations (W) ṁ renov − Infiltration air flow (kg/s) E ar − Specific energy of air (J/kg) Q̇p=ṁ rot . C P (T in − T 1 ) Q̇i = Q̇o + Q̇l + Q̇e [W] (3) Q̇inf =ṁ renov E ar [ ] (4)