An integrated combined power and cooling strategy for small islands

It is crucial to ensure food security to continue the sustainable nutrition of the world population. Food losses in the global food supply chain pose a significant risk to food security. Especially foods that require cold chain logistics are prone to deterioration and eventually food losses. Therefore, cold chain logistics processes require operational expertise and specialized equipment. Reefer (refrigerated) container is the most used cold chain transport equipment for perishable foods requiring atmospheric control. Analyzing operational and hardware‐related causes and implementing relevant countermeasures are necessary to prevent food losses in reefer containers. With this motivation in the study, the relationships between the factors causing food losses in the reefer containers were evaluated qualitatively and quantitatively via the model built using the Fuzzy Bayesian network method. The findings indicate that the most critical root causes of food losses in reefer containers are excessive time off‐power, inappropriate preload conditions, and refrigerant faults, respectively. Moreover, the riskiest combination of factors that causes food loss consists of excessive time‐off power, refrigerant faults, and adverse weather conditions during navigation and in port. When the existing legal framework and professional practices are examined, in light of the results of the study, the following will be recommended: Establishing minimum standard and maintenance arrangements for cooling systems, ensuring safety margin in the shelf life of the foods carried in the reefer containers, making mandatory the automatic temperature recordings systems, and increasing the number of personnel specialized in product types and transportation. The study results will benefit supply chain stakeholders for process planning and implementation to mitigate the risk of food losses in reefer containers.Practical applicationsThis study examines the factors causing food losses in reefer containers from loading to discharge. The findings indicate that the most critical root causes of food losses in reefer containers are excessive time off‐power, inappropriate preload conditions, and refrigerant faults, respectively. When the existing legal framework and professional practices are examined, in light of the results of the study, the following will be recommended: Establishing minimum standard and maintenance arrangements for cooling systems, ensuring safety margin in the shelf life of the foods carried in the reefer containers, making mandatory the automatic temperature recordings systems, and increasing the number of personnel specialized in product types and transportation.

Ships used for shipping goods, especially on the MV. Cap San Juan there are things that must be considered, one of which is the reefer container which has strict maintenance and control to know that the reefer container can work optimally. In this case the reefer container has a risk of damage to its components so that the reefer container does not function as it should. Therefore, it is necessary to discuss as a form of effort in handling if damage occurs and unwanted obstacles occur. This study aims to determine the causes and effects of mechanical damage to reefer containers on ships and to find out how to overcome reefer containers that experience mechanical damage on the high seas based on field conditions. The research method used is a qualitative method using data collection techniques through observation, interviews and documentation regarding the handling of reefer containers when problems occur. Based on the results of observations made by the author regarding the various obstacles that occur in reefer containers during sea practice, there are two causes, namely component damage because it has passed the time limit for use and an electrical short circuit in one of its components which causes the reefer container to not be able to work optimally. This happened because there was no thorough checking and lack of maintenance.

Fresh fish is sensitive to storage temperature. Temperatures above 2 °C accelerate the growth of bacteria and cause spoilage. The optimal storage temperature for frozen fish is -20 °C. Reefer container with a closed cooling system serves to preserve by maintaining the temperature of frozen fish. The problem of this research is the uneven distribution of cold air in the reefer containers of the train, thereby reducing the quality of frozen fish. The purpose of this research is to increase the even distribution of air, velocity, and pressure in the reefer container of the train. The solution to the problem is simulation and analysis of the condition of the reefer container train using Computational Fluid Dynamics (CFD). Reefer containers without guide plates are simulated to find out the area of the train reefer containers that are not evenly distributed. The distribution of air in the reefer container of the train is improved even by the addition of guide plates with variations in angles of 40°, 50°, and 60°. This research produces qualitative data (velocity contour and pressure contour reefer container) and quantitative (average velocity and pressure). The results of this study are CFD simulation data of uniform distribution of air, speed, and pressure on the reefer container train with a 40⁰ guide plate.

Marine reefer containers may transport goods at their different best temperatures to any port in the world in a rapid, safe, flexible and economical way, so it has become the most important new means of transport in the international trade. However, during the ocean going transportation, influenced by such changing interference factors as navigation area, solar radiation angle, air and water temperature, reefer containers work under complex and adverse conditions in a long time, so reefer container faults and cargo damage take place frequently. Coupled with increasing types of cargo, only to rely on manual inspections and on-site diagnosis is not only inefficient but also ineffective. Thus, it has put forward higher requirements on the condition monitoring and fault diagnosis system of ocean going reefer containers. In the paper, a data wireless transmission and condition monitoring system of marine reefer containers based on the serial communication interface is designed and a remote monitoring and fault diagnosis system based on Inmarsat F is put forward. With its application to the ocean going ships, it will undoubtedly have great practical significance to the safety operation and economic efficiency of marine reefer containers.

The reefer container market and academic research: A review study

Under the background of rapid development of internet of things, cloud computing, mobile communication and big data technology, Shanghai Maritime University cooperated with Cosco Shipping Container Lines Co., Ltd. to develop a complete set of intelligent monitoring system for reefer container. Based on the carding of various links in the process of reefer container transportation, statistical analysis was made on the historical operation data of 200 reefer containers in the past 2 years, and the power supply and power outage cycles in the actual production process were quantified Analysis. By calculating the proportion of reefer container that have lost the connection under different battery life conditions, a strategy is provided for selecting suitable battery life for the reefer container IoT monitoring device and also Prolonging the service life of the device.

In its use, reefer containers require a lot of energy to operate to cool the cargo inside. Because the cooling system in the reefer container must operate continuously to maintain the temperature in the container. To reduce the operation of the cooling system, reefer containers are equipped with PCM (phase change material) as thermal energy storage which can store heat energy longer to create a lag time for the operation of the cooling system. In previous research, the use of PCM in cold storage can save the cost of using cold storage. From this research, the use of PCM in reefer containers was developed. The eutectic mixture used as PCM is NaCl-H2O with additional ingredients is propylene glycol. Before being applied to the reefer container, the mixture was tested using the cooling chamber methods to determine its thermophysics. The presence of additives in the PCM eutectic mixture is expected to reduce the supercooling phenomenon, reduce corrosive properties and increase the use of PCM based on NaCl-H2O.

Servicing the reefer containers at sea ports requires more reliability and precision than servicing the conventional ones because of specificity of perishable cargoes shipped in them. This paper is aimed at making analysis of way of servicing the reefer containers stored at sea port and at investigating its influence on storing conditions of refrigerated cargoes contained in them. Lack of the electricity supply to refrigerating unit of reefer container is one of the most common extraordinary situations in port area, which may lead to loss of quality of cargo contained in the container. On the basis of scenarios of possible progress of such situations, elaborated by means of calculations, rate of change of temperature of cargo in reefer containers cut-off from electricity supply source was determined and relevant recommendations as to organization of sevicing such containers at sea port, were elaborated.

In the transportation of skipjack tuna to various destination countries, it is crucial to ensure that the skipjack tuna persists and remains of high quality. This study aims to analyse the airflow distribution inside the reefer container with the cargo load of skipjack tuna. The analysis carries out the computational fluid dynamics method to obtain appropriate airflow settings and investigate the temperature distribution inside reefer containers. The designed reefer container is 40ft with detailed structural variables of the T-bar and flat floor. The simulation result shows reefer containers that use the T-bar floor provide offer a thorough airflow distribution to cooling pallet stacks with full load conditions. The finding of the simulation results is the airflow rate of 5 m/s and the inlet temperature of -6°C will provide optimal cooling distribution.

Today, fresh, chilled, or frozen products usually use reefer containers. The main problem with using reefer containers is the large energy consumption of 3.6kW/TEUS and the continuous supply of electric power. One solution available is using Phase Change Material (PCM) in the hybrid refrigeration system combined with a vapor compression system. Using PCM, the temperature of the reefer container can be maintained for several hours of cooling with the compressor off. This research aims to simulate the performance of a hybrid refrigeration system using PCM and the distribution of cooling air temperature in a laboratory-scale eco-reefer container. A simulation was performed using numerical software and CFD software. From the simulation analysis, the power value of the compressor at -20 °C is 0.3794 kW for the conventional system, 0.463 kW for the 22% NaCl PCM hybrid system, and 0.411 kW for the 20% Propylene Glycol PCM hybrid one. The COP value is 2,560 for the conventional system, 2,572 for the 22% NaCl PCM hybrid system, and 2,569 for the 20% Propylene Glycol PCM hybrid one. The CFD simulation results that PCM NaCl and Propylene Glycol can maintain the reefer container room temperature and product load.

Internal ambiance monitoring of reefer containers using the Internet of Things (IoT) is important for cold chain tracking and traceability. However, disruptions due to power fluctuations, communication failures, and sensor malfunctions can lead to missing values in the data streams, impacting the effectiveness of the monitoring system. Existing algorithms addressing this issue assume the stationarity of the training dataset, ignoring the fact that the real-world datasets are mostly nonstationary. This article presents a two-stage framework to address this issue in the context of reefer container monitoring. The first stage detects the missing values and segments the training set, while the second stage employs a rotational transformation (RT), followed by an imputation algorithm. The framework is demonstrated using datasets collected during the remote monitoring of a reefer container, which is found to be nonstationary using the augmented Dickey-Fuller (ADF) test. The accuracy is evaluated using metrics such as RMSE, MAE, MAPE, and mean (bias) and shows better performance of the imputation algorithms with the proposed transformation compared to without it or with few other existing ones. Besides the imputation accuracy, the information preserved within the transformed dataset is evaluated using mutual information. The results suggest that the amount of retained information in the case of the proposed approach surpasses that of existing techniques. In addition, a metric to assess the predictive capability of an algorithm for a specific dataset is used to evaluate the framework, and the results indicate improved predictability compared to the existing ones.

Numerical simulation and experimental study on marine cabin's ventilation for reefer containers

The amount of food transported long distances in reefer containers is constantly increasing and so is the cost per mile because of rising fuel prices. One way to reduce the cost is to minimize the energy consumed by reefer containers through a better controller but in order to achieve this a fast and flexible simulation model is needed for controller development. The simulation model may also be used for developing fault diagnosis methods for the reefer container and thereby further lowering costs by reducing the amount of functioning spare parts that is replaced and by providing early warning for faults enabling preventive maintenance. In this paper the feasibility of using different simulation methods is assessed with the goal of identifying a fast but accurate method that works well in a multi-rate environment. A modular multi-rate simulation environment for a dynamical system consisting of components with different dynamical speeds is presented with an improvement of previous results. The simulation speed is improved by 350% with no reduction in the accuracy of the solution, by substituting the Matlabode15s solver with an explicit first-order solver with a step-size calculation algorithm that ensures numerical stability and that the error is bounded using a minimum of calculations. The reefer container model is simulated using both ode15s and the proposed method both in multi-rate and monolithic configurations. The results are analyzed and compared with respect to speed and accuracy.

Developing an efficient and well-organised reefer container transportation network in the port hinterland is essential for facilitating land-sea perishable product transportation. This paper proposes a port-hinterland hub network design method for reefer containers. Considering the diverse supporting service requirements and seasonally time-varying demand of reefer containers, virtual links and nodes were introduced to model a realistic heterogeneous hub deployment issue. This enables hubs to provide various service functions. Additionally, a tailored robustness metric was developed to evaluate network performance under fluctuating demands. The bi-objective network model aims to minimise total costs while maximising network performance. An improved multi-objective particle swarm algorithm is developed to efficiently solve the model. Real case results demonstrate that the proposed method effectively manages network design under time-varying demands. It offers a range of solution schemes with varying levels of time-domain robustness, ensuring stable network performance despite fluctuations in demand. The experiments on the impact of demand seasonality provide operational recommendations for relevant stakeholders. Trial registration Netherlands National Trial Register identifier: NTR-11.. Trial registration Netherlands National Trial Register identifier: NTR-13.. Trial registration Netherlands National Trial Register identifier: NTR-15.. Trial registration Netherlands National Trial Register identifier: NTR-16.. Trial registration Netherlands National Trial Register identifier: NTR-9..

To investigate the effect of the location of vacuum insulation panels on the thermal insulation performance of marine reefer containers, a 20ft mechanical refrigeration reefer container was employed in this paper, and the physical and mathematical models of three kinds of envelopes composed of vacuum insulation panels (VIP) and polyurethane foam (PU) were numerically established. The heat transfer of three types of envelopes under unsteady conditions was simulated. In order to be able to analyze theoretically, the Rasch transform is used to analyze the thermal inertia magnitude by calculating the thermal transfer response frequency and the thermal transfer response coefficient for each model, and the results are compared with the simulation results. The results implied that the insulation performance of VIP external insulation is the best. The delay times of each model obtained from the simulation results are 0.81 h, 1.45 h, 2.03 h, and 2.24 h, while the attenuation ratios are 8.93, 20.39, 20.62, and 21.78, respectively; the delay times calculated from the theoretical analysis are 0.78 h, 1.43 h, 1.99 h, and 2.20 h, respectively; and the attenuation ratios are 8.84, 20.31, 20.55, and 21.72, respectively. The carbon reduction effect of VIP external insulation is also the best. The most considerable carbon reduction is 3.65894 kg less than the traditional PU structure within 24 h. The research has a guiding significance for the research and progress of the new generation of energy-saving reefer containers and the insulation design of the envelope of refrigerated transportation equipment.