Numerical modelling and experimental validation of a cold store ambient factors

Abstract

The objective of this study was to analyse air temperature and relative humidity distribution in an experimental cold store fully loaded with apples by using both experimental and numerical (CFD) methods. An unsteady three-dimensional computational fluid dynamics model was developed to assess the distribution of temperature and relative humidity in a cold store fully loaded with Granny Smith apples. The storage temperature and relative humidity were maintained at 2 °C and 90%, respectively. The relative humidity and temperature were measured at 36 different points inside the cold store in three different planes. A three-dimensional mathematical model was built for the numerical needs. The numerical model was validated against experimental data from the same facility. Relative error of the model was calculated 13% for temperature and 1.43% for relative humidity. Numerical results obtained from the simulations agreed quite well with experimental data for temperature and relative humidity. Maximum differences were observed near the borders of the cold store which can be attributed to the stronger thermal gradients taking place on these surfaces. A more homogeneous distribution was achieved in the middle of the cold store both for air temperature and relative humidity leading to even smaller errors between measurements and simulations.

Numerical Study of the Impact on Cooling Behaviour of Vent-Holes Design of Fruit Packaging Boxes

“…The maintenance of adequate temperature slows down the biochemical processes responsible for senescence [8]. Fruit remains physiologically active after harvest resulting in the reduction of quality [9,10]. Adequate cooling is of critical importance when dealing with post-harvest perishable fruits as the mentioned physiological phenomena generates heat that can lead to premature and excessive ripening [11] and the development of colony forming units of microorganisms.…”

“…Cooling heterogeneity can lead to damage in the produce due to some locations becoming colder or hotter than ideal [1,11] and it is difficult to evaluate using average values [9]. One of the factors affecting cooling uniformity during precooling is the presence of turbulent airflow due to the shape of food products and the packaging [15,16].…”

“…Therefore, packaging should be designed to prevent heterogeneity by adjusting vent size and position to the necessities of the food products [6,17]. However, perfect cooling uniformity is impossible to operational and environmental conditions as well as biological variance of perishable food products [9,10]. Virtual cold chain simulation clearly demonstrates the negative effects of cooling heterogeneity in the quality of food products [14].…”

“…Fortunately, packaging is one of the easiest parameters to change in post-harvest cold chain as it is not particularly expensive or overburdened with regulations [7]. Also, significantly less expensive is the use of CFD simulations per opposition to experimental tests and computational capabilities becomes less expensive, simulation become more attractive as it can provide accurate spatial and temporal predictions with a resolution and consistency that would be extremely difficult to achieve through experimentation [2,6,7,9,10,26,28,29].…”

Devising a method to improve the accuracy of maintaining the pre-set temperature and humidity conditions at a vegetable storage facility under a food storing mode

“…This index is seasonal in nature and depends on the capability to meet the need due to internal storage in vegetable storage facilities. Therefore, seasonality and the need for products create the need for their long-term and high-quality storage [2].…”