• Energy Research

Packaging was recently identified as an essential element in addressing the key challenge of sustainable food supply and is gaining interest among researchers. It is a central element in food quality preservation due to its role in heat and mass exchange with the external atmosphere, contributing to the preservation of food quality during storage and extending food shelf life. This work proposes three new packaging configurations with the same size but different geometry and ventilation hole sizes and geometry, that change the conditions in which the heat and mass exchange occurs, during either the cooling period of fruits, inside the cooling chamber, or during the period when the packaging is exposed to ambient conditions, outside the cooling chamber. For this purpose, packages with fruit models that replicate the properties of real fruit were subjected to a cooling process inside a cooling chamber for 8 h. Subsequently, during the heating phase, the packages were exposed to ambient conditions for 10 h. Thermal conditions were also monitored, both inside and outside the chamber. Additionally, for comparative purposes, the thermal behavior of commercial packaging was also evaluated for the same operating conditions in the cooling and heating phases. The results show that the new packages do not substantially promote the preservation of fruits in the cooling phase, but in the heating phase, they ensure an extension of the period with proper thermal conditions of up to 50% in relation to the conventional packaging. This result is particularly important since the heating phase, in which fruits are outside the storage chamber, is the period with the greatest impact on the fruits’ useful life.

This study proposes an innovative approach to reduce temperature fluctuations in refrigerated transport during loading and unloading, aiming to minimize food waste and optimize energy consumption in the food supply chain. The solution involves integrating Peltier cells into secondary and tertiary packaging to improve system efficiency and minimize temperature variations. Four distinct tests were conducted: a reference test, continuous Peltier system operation, and two intermittent cooling tests for the hot side of the cells. The results highlight the effectiveness of this approach, particularly in the fourth test where the average final food temperature decreased from 3.2 °C (reference test) to 2.8 °C. Integrating Peltier cells into packaging shows potential benefits in minimizing food waste, reducing energy consumption, and associated emissions during refrigerated transport. This research contributes to the sustainable design and manufacturing of packaging systems, specifically in the context of refrigerated transport. By maintaining a consistent temperature environment during the critical loading and unloading phases, incorporating Peltier cells enhances the overall performance and efficiency of refrigerated transport system. These results point out the significance of exploring innovative solutions for sustainable food preservation and the decrease of waste all along the food supply chain.

Thermal comfort is one of the most important ergonomic aspects of building occupancy. In this research, laboratory experiments are performed in a climatic chamber and described in detail. Experiments are carried out under two scenarios: with two different college students cohorts and with five different but comparable experimental conditions in each cohort. Three hundred twenty‐two individual assessments under specific controlled thermal environment conditions are collected. The actual thermal sensation assessments obtained in the experiments are compared to the results obtained by a predicted mean vote (PMV) model. The correlation analysis shows that statistically significant differences are meaningful between the spring‐summer and the autumn‐winter experiments but not between genders. This paper discusses the plausible factors contributing to the different correlations experienced in the autumn‐winter and spring‐summer experiments. A correction factor between PMV according to Fanger's comfort equation and the actual thermal sensation values reported by the participants is also sought with a focus on the seasonal effects. The predicted results are in good agreement with the experimental results. This allows for further considerations about the influence of the season on the initial thermal sensations experienced by young adults.

This paper provides a characterization of the electrical energy consumption of agrifood industries located in the central region of Portugal that use refrigeration systems to ensure the food safety. The study is based on the result analysis of survey data and energy characteristics of the participating companies belonging to the following agrifood sectors: meat, dairy, horticultural, distribution and wine. Through the quantification of energy consumption of companies is possible to determine the amount of greenhouse gases (GHGs) emissions indexed to its manufacturing process. Comparing the energy and GHGs emissions indexes of companies of a sector and between sectors is possible to create reference levels. With the results of this work is possible to rating the companies in relation to reference levels of energy and GHGs emissions and thus promote the rational use of energy by the application of practice measures for the improvement of the energy efficiency and the reduction of GHGs emissions.

In Portugal the meat sector occupies the highest rank within the food industry having its electricity consumption grown at a high pace mainly due to the intense use of refrigeration systems. This paper assesses the electric energy consumption profile of Portuguese meat industries and estimates the potential savings with a set of simple energy efficiency measures which result from the best practices in the sector. Taking in account the fieldwork, some of the most relevant measures carried out are: to improve production process management in order to avoid the use of cold chambers partially loaded; to improve thermal resistance of the buildings envelope, cold chambers and refrigeration pipes; to avoid installation of condensation groups in warm places (exposed to solar radiation or in non-ventilated attics). The results show a potential reduction in electricity consumption of 24% for slaughterhouses (474 MWh), 13% for sausage houses (322 MWh), and 8% for ham production (708 MWh).

Abstract Energy is fundamental for present societies. In particular, transportation systems depend on petroleum-based fuels whose production levels are unsustainable. The inevitability of a peak of oil production (“Peak Oil”) is a now an accepted concept, although its date is still not consensual. In this work we discuss the peak of oil production and analyze the problems it will create. As much as can be inferred at this moment, the impact of the Peak Oil will certainly be significant but can still range from relatively benign to almost catastrophic scenarios. As a direct effect of Peak Oil, the increase in energy prices will be concentrated on the liquid fuels and the transportation sector will be specially affected. We believe that the cheap, wide-scale air transport that our present societies take for granted will revert to a more expensive and restrictive model closer to the selective commercial air transport of the early jet age. In our opinion the present road transportation systems will suffer an important transition that includes a reduced incidence of long distance road cargo movements, partially replaced by increased railway transportation, and, in terms of people commuting, a significant increase of mass transit and electrical vehicles. During this phase of forced adaptation, some countries will face greater challenges than others. However, the future of overall mankind and of particular countries, regions, or any groupings of people, is not yet fixed: it depends on decisions that are being taken at the present moment and on decisions that will still be taken in the future. As such, predicting the impact of the Peak Oil is something that must be done through a continuously refined process of information collection and analysis.

Abstract Nowadays, all industry, including the agri-food sector, faces the urgent need to increase its competitiveness in order to survive in a global market. In this context, it is vital to ensure a strong, renewed and innovative industrial base throughout all stages of the value chain, capable of competing internationally and differentiating itself by the quality of its products and services. Since wealth generation cannot be dissociated from productivity, which in turn is closely related to the trinomial: processes, technologies and quality, it is concluded that the implementation of this strategy requires a commitment to the qualification of organizational management, operational management, project management and processes and productive systems themselves and associated technologies. This paper presents the characterization of the energy consumption and technologies in bakery and pastry sector, one of the most significant in the Portuguese agri-food sector.