Pedro D. Silva

University of Beira Interior | UBI · Department of Electromechanical Engineering

The thermal performance and energy efficiency of buildings are critical factors in achieving sustainable energy systems as energy needs for heating and cooling are expected to represent more than 50% of global final energy consumption. This study analyzes conventional renewable energy systems for heating and cooling in buildings, focusing on strate...

This article proposes the use of a thermoelectric system as an energy-harvesting device for use in industrial refrigeration units. The energy generated by the device in this study can be used for remote, low-power applications, such as frost detection sensors. The accumulation of frost on the surfaces of evaporators causes inefficiency in the opera...

Frost formation in heat exchangers can lead to issues related to the efficiency and performance of refrigeration systems. This happens due to the accumulation of frost on the surface of heat exchangers that acts as a thermally insulating barrier that also restricts, or even blocks, the airflow between fins. Several methods of defrosting have been d...

The global effort to feed a growing population is not only focused on increasing food production, but also on decreasing food waste. Perishable foods, such as most horticultural products, demand specific conditions for optimum preservation. Two of the most important characteristics to control are temperature and humidity. Inadequate temperature and...

Atmospheric water generation (AWG) is a technological innovation that facilitates the extraction of water from the atmosphere using various techniques. In response to mounting concerns regarding water scarcity in multiple regions globally, AWG has emerged as a promising solution for providing potable water in areas where conventional water sources...

Maintaining a stable temperature is critical in ensuring the longevity of perishable foods, and frequent fluctuations due to short-range distribution conditions can negatively affect this stability. To mitigate these variations, an innovative modular packaging system utilizing phase change materials (PCMs) was employed in the transport and storage...

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...

Heat exchangers (HXs) play a critical role in maintaining human thermal comfort and ensuring product safety and quality in various industries. However, the formation of frost on HX surfaces during cooling operations can significantly impact their performance and energy efficiency. Traditional defrosting methods primarily rely on time-based control...

The thermal performance and environmental impact of agricultural greenhouses (GH) connected to earth-to-air heat exchanger (EAHE) systems depend on the ambient temperature, soil temperature, EAHE system, and greenhouse specifications. The impact of an EAHE system on the temperature and humidity of a GH microclimate, as well as its effects on CO2 em...

Temperature is the parameter that most affects the rate of deterioration of horticultural products and their postharvest life. Therefore, fast removal of heat from the field after harvesting by cooling and maintaining the ideal temperature of the product is of utmost relevance in supply logistics. A transient three-dimensional CFD model of a cold c...

Temperature variations in the food transportation chain represent a problem in food quality preservation contributing to rising of the food waste. Raise in temperature during different phases of transportation adversely affects the overall quality of the products. To overcome the temperature abuse during the cold chain, maintaining optimum temperat...

Peach is a highly perishable climacteric fruit. Cold storage is the most widely used method for peach storage, delaying fruit deterioration. This study describes the experimental tests developed to evaluate the evolution of peach characteristics under different storage conditions of controlled (CA) and normal atmosphere (NA) of ‘Sweet Henry’ cultiv...

Food waste results in an increased need for production to compensate for losses. Increased production is directly related to an increase in the environmental impact of agriculture and in the energy needs associated with it. To reduce food waste, the supply chain should maintain ideal preservation conditions. In horticultural products, temperature,...

Appropriate measures have been taken to reduce energy requirements for cold chain applications. Thermal energy storage is an accepted method to reduce the need for electrical energy after harvesting fresh horticultural produce. The use of phase change materials (PCM) in postharvest storage, outside of a temperature-controlled environment, extends s...

Air temperature and relative humidity values of cold storage conditions are the major factor affecting the perishability of fresh fruits. The sooner the field heat is extracted from the products and the proper temperature is maintained consistency throughout the cold chain, larger it will be shelf life of these products. Forced air cooling is the m...

The frost formation and growth on the exchange surfaces of the evaporators that are part of the refrigeration systems that are usually found in the cold chambers for the preservation of food products affects the thermal performance of these equipments by conditioning the heat transfer between the heat exchange surfaces and the fluid flow, usually a...

O Capítulo 5 - Efeito de diferentes condições de conservação na qualidade da cereja da cv. Satin apresenta os resultados de um ensaio de conservação, que decorreu durante 4 anos, que incluiu a utilização de Atmosfera Normal e Atmosfera Controlada, com vista ao prolongamento da vida útil da cereja.

Nowadays, the strong increase in products consumption, the purchase of products on online platforms as well as the requirements for greater safety and food protection are a concern for food and packaging industries. Active packaging brings huge advances in the extension of product shelf‐life and food degradation and losses reduction. This systemati...

The temperature at which perishable products are stored significantly affects their shelf-life. The purpose of this work was to evaluate the performance of a new packaging box containing alveolus with phase change materials (PCM). During the experimental tests and in the cooling process, the products were placed inside a conservation chamber with t...

Fresh food quality and safety are influenced by temperature variation in the food chain. Phase change materials (PCM) in packaging contributes to preserve food quality and extending food shelf life. A transient 3D CFD model was developed to predict the thermal performance of fruit packaging boxes with PCM alveoli. The thermal performance is analyse...

Smart packaging provides one possible solution that could reduce greenhouse gas emissions. In comparison with traditional packaging, which aims to extend the product's useful life and to facilitate transport and marketing, smart packaging allows increased efficiency, for example by ensuring authenticity and traceability from the product's origin, p...

Frost formation in the heat exchangers of refrigeration systems is a well-documented phenomenon. This frost accumulation creates a thermally insulating barrier that can restrict, or even block, the airflow between fins, resulting in decreased efficiency and degradation of the food products. Several methods of frost detection and defrosting have bee...

Sweet cherry is a highly appreciated seasonal fruit with a high content of bioactive compounds; however, this highly perishable fruit has a relatively short shelf-life period. Here, we evaluated the evolution of the physicochemical and sensory qualities of sweet cherries (Prunus avium (L.) cv. Satin) under different storage conditions, namely at a...

Air temperature and relative humidity values of cold storage conditions are the major factor affecting the perishability of fresh fruits. The sooner the field heat is extracted from the products and the proper temperature is maintained consistency throughout the cold chain, larger it will be shelf life of these products. Forced air cooling is the m...

The need for production of all kinds of crops in high quantities and over the entire year makes the agricultural sector one of the major energy consumers. The optimization of this consumption is essential to guarantee its sustainability. The implementation of greenhouses is a strategy that allows assurance of production needs and possesses large op...

The shelf life of perishable products depends mainly on the conservation of air temperature. Packaging boxes are usually used to accommodate food products during cold storage and transport and/or display. The design of the vent-holes of the packaging box must promote cold airflow and remove the field heat of the produce after harvest at a short tim...

This project intended i) to evaluate the effect of refrigeration and controlled atmospheres in the conservation of sweet cherry and peach; ii) to develop smart packages that maintain the organoleptic characteristics while controlling the respiration of the fruit and the heat transference by the package. In order to fulfil these objectives, the stud...

A sustentabilidade pode ser definida como a capacidade de o ser humano interagir com o mundo, preservando o meio ambiente de forma a não comprometer os recursos naturais das gerações futuras. O projeto S4AGRO - Soluções Sustentáveis para o Setor Agroindustrial visa qualificar as PME (pequenas e médias empresas) do setor agroindustrial, as mais rece...

A sustentabilidade pode ser definida como a capacidade de o ser humano interagir com o mundo, preservando o meio ambiente de forma a não comprometer os recursos naturais das gerações futuras. O projeto S4AGRO - Soluções Sustentáveis para o Setor Agroindustrial visa qualificar as PME (pequenas e médias empresas) do setor agroindustrial, as mais rece...

A sustentabilidade pode ser definida como a capacidade de o ser humano interagir com o mundo, preservando o meio ambiente de forma a não comprometer os recursos naturais das gerações futuras. O projeto S4AGRO - Soluções Sustentáveis para o Setor Agroindustrial visa qualificar as PME (pequenas e médias empresas) do setor agroindustrial, as mais rece...

A sustentabilidade pode ser definida como a capacidade de o ser humano interagir com o mundo, preservando o meio ambiente de forma a não comprometer os recursos naturais das gerações futuras. O projeto S4AGRO - Soluções Sustentáveis para o Setor Agroindustrial visa qualificar as PME (pequenas e médias empresas) do setor agroindustrial, as mais rece...

A sustentabilidade pode ser definida como a capacidade de o ser humano interagir com o mundo, preservando o meio ambiente de forma a não comprometer os recursos naturais das gerações futuras. O projeto S4AGRO - Soluções Sustentáveis para o Setor Agroindustrial visa qualificar as PME (pequenas e médias empresas) do setor agroindustrial, as mais rece...

A sustentabilidade pode ser definida como a capacidade de o ser humano interagir com o mundo, preservando o meio ambiente de forma a não comprometer os recursos naturais das gerações futuras. O projeto S4AGRO - Soluções Sustentáveis para o Setor Agroindustrial visa qualificar as PME (pequenas e médias empresas) do setor agroindustrial, as mais rece...

A sustentabilidade pode ser definida como a capacidade de o ser humano interagir com o mundo, preservando o meio ambiente de forma a não comprometer os recursos naturais das gerações futuras. O projeto S4AGRO - Soluções Sustentáveis para o Setor Agroindustrial visa qualificar as PME (pequenas e médias empresas) do setor agroindustrial, as mais rece...

A sustentabilidade pode ser definida como a capacidade de o ser humano interagir com o mundo, preservando o meio ambiente de forma a não comprometer os recursos naturais das gerações futuras. O projeto S4AGRO - Soluções Sustentáveis para o Setor Agroindustrial visa qualificar as PME (pequenas e médias empresas) do setor agroindustrial, as mais rece...

Three composite materials with different CaZrO3/MgO fractions (2/3, 1/2, 1/3) and two single-phase materials (CaZrO3 and MgO) were fabricated and their thermal conductivity was investigated. Complete thermal and mechanical characterizations (thermal expansion coefficient, thermal diffusivity, specific heat, hardness and toughness) of the materials...

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 a...

Peach is a very perishable climacteric fruit whose firmness may decay rapidly depending on the temperature. Refrigeration is usually used to delay ripening and maintain fruit quality. However, often temperature storage conditions are not optimized. This work aims to characterize the storage conditions (temperature and humidity) of three peach prod...

This work aims to present a thermographic database of healthy vulva images and to explain the entire process of acquisition, processing, and analysis of the thermograms and other non-image information. We performed thermographic acquisitions of the vulva of 86 asymptomatic women and, after pre-processing and analyzing the thermograms, we obtained a...

Food safety and eradication of food waste are current concerns of society and governments due to health, ethics, and sustainable economics. There are multiple technologies for monitoring food safety at different chain stages, among them, time-temperature integrators (TTI). Temperature is a major factor affecting food quality and safety during its l...

Refrigeration is one of the key elements for food preservation. With global temperatures increasing due to global warming, the efficiency in refrigerated storage systems must be improved. One of the problems that is yet to be solved in these systems is the efficient and accurate removal of the frost formed on the heat exchanger surface. In previous...

During food transport, products are often subject to conditions which do not benefit the conservation of their biological properties. This condition can lead to food quality and safety issues and ultimately to food waste. Globally, there was been an effort to develop techniques, procedures and technologies that can contribute to reduce food waste o...

This experimental task was performed using 8 sustainable Bio-Boxes in the thermal chamber in the laboratory. The air is forced from the refrigerator, and it is used to control the temperature inside the thermal chamber. The goal of the performed task is to evaluate the thermal behaviour of the bio Boxes made from different material, such as sugarca...

A sustentabilidade pode ser definida como a capacidade de o ser humano interagir com o mundo, preservando o meio ambiente de forma a não comprometer os recursos naturais das gerações futuras. O projeto S4AGRO - Soluções Sustentáveis para o Setor Agroindustrial visa qualificar as PME (pequenas e médias empresas) do setor agroindustrial, as mais rece...

Reducing food waste demands improvements in refrigeration systems. Furthermore, the rise of temperatures worldwide demands more capable and efficient refrigeration equipment. One of the problems that affects refrigeration equipment is the accumulation of frost in the heat exchanger that reduces efficiency, and in extreme cases, blocks the air flow....

Refrigeration systems are crucial for food storage. Nowadays with the global warming affecting the temperatures worldwide, more efficient and robust systems must be designed to avoid a decay in the quality of food preservation. One of the problems that must be tackled in these systems is the frost formation on the evaporator, as it reduces the heat...

Sustainable and innovative packaging industry has been facing a lot of changes. Technological innovations concentrating on marketing, labelling and extending shelf life, as well as protecting the environment, are transforming the future of packaging. In the current intensive plastic packaging analysis, manufacturers are exploring alternative soluti...

The post-harvest life of fresh horticulture products mainly depends on the cold storage, as the temperature is the primary element in affecting the shelf life of these highly perishable goods. A rapid removal of field heat and preserve the desired temperate consistency throughout the cold chain management is the deciding factor for the quality of t...

Simple energy surveys and audits were performed in 60 processing industries of meat, dairy, horticultural and bread and pastry products, located in the North, Center and Alentejo regions of Portugal. The number of refrigeration chambers, building infrastructure and energy consumptions of the equipment used in the manufacturing processes were evalua...

Post-harvest cold storage of peaches is an essential element to maintain the quality of the fruits without any loss. This work aims to present a CFD model, to predict airflow patterns and temperature profiles in ventilated packaging systems, during the forced-air cooling of Peaches stored in a cold chamber. Transient CFD simulations are performed f...

Active packaging aims to extend the shelf life of fruits and vegetables using active agents such as Oxygen, Carbon-dioxide , ethylene scavengers and moisture absorber. Intelligent packaging provides information about the fruits quality inside the package to the customer and this packaging technology detects the internal changes of fruits and vegeta...

The peach is a stone fruit with a very juicy flesh, smooth skin, and a taste that satisfies the most demanding palate. The quality of this fruit is usually determined by texture, appearance, scent, flavor, and nutritional value. Peaches are very sensitive fruits, which deteriorate and ripen very quickly at environment temperature. Cold conservation...

Nowadays, solar energy, which can be photovoltaic and thermal, is a clean and reliable source of energy for the production of electric and thermal power. However, new ways for improving photovoltaic efficiency are fundamental for an extensive application of this technology. Most of the energy absorbed by the PV panel converts itself into heat, whic...

In recent years, reducing energy consumption has been relentlessly pursued by researchers and policy makers with the purpose of achieving a more sustainable future. The demand for data storage in data centers has been steadily increasing, leading to an increase in size and therefore to consume more energy. Consequently, the reduction of the energy...

Abstract: Currently, there is a growing demand for cleaner and sustainable technologies due to environmental issues. In this sense, there is a necessity to manage the assessment of production processes and the rationalization of energy consumption. In this study, an Energy Life-Cycle Assessment (ELCA) was carried out through energy efficiency indic...

This paper presents the current status and future trends of sensor technologies for food products traceability, specifically for systems devoted to be applied in the cold storage and refrigerated transport of horticultural products. The available monitoring technologies such as dataloggers, TTI, WSN, RFID, and combined approaches are evaluated and...

Cherry is a highly perishable fruit widely appreciated that is only commercialized during a short period. The post-harvest control and monitoring of this fruit is central and essential for optimal consumption in its highest state of quality. The conservation process aimed to inhibit the microbial propagation is usually accomplished by low temperatu...

This paper presents the results of audits performed in 60 companies of the food processing industry, specifically of meat, dairy, horticultural and bread products. The refrigeration volume, type of refrigeration system, refrigerant, building and insulation materials of infrastructure and refrigeration chambers, average air temperature and humidity,...

The processing efficacy and energy efficiency of data centers (DC) is directly related with the cooling performance of the airconditioning systems. The cooling effectiveness depends on airflow pattern and temperature distribution. This paper presents the parametric study of three-dimensional (3D) computational fluid dynamics (CFD) models to improve...

Fin-and-tube heat exchangers (HX) have wide application in the industry. The study of HXs with reduced tube diameter has allowed the development of more compact and equally efficient equipment. Most of the HXs of this type are composed of flat fins, not only due to the ease of construction but also to their reliability in long-term operation and re...

This paper presents the experimental and numerical results of a set of air curtain evaluations in a Vertical Open Refrigerated Display Cases (VORDC) when subjected to external disturbances due to the transfer of people in front of the air curtain. Previous experimental studies identified that the stability of the air curtain depends on the climatic...

This paper reports the results of experimental tests performed according to ISO 23953 in vertical open and closed refrigerated display cabinets (VORDC vs. VCRDC). Tests were performed at a mild climate class (n. º 3: T=25°C; φ=60%) and a tropical one (n. º 6: T=27°C; φ=70%). The direct energy consumption is 46% higher at VCRDC due to the heated gla...

Refrigeration systems are widely accepted as a mean to prevent food degradation. These systems usually rely on fin-and-tube heat exchangers to lower the air temperature. Due to long operation times and surface temperatures below dew point, frost may form and accumulate on the evaporators fin surface. This frost accumulation reduces and may clog the...

The use of cold for conservation of food products requires large consumption of electricity. In order to obtain lower temperatures than those available in the same space, the evaporator coils, generally operate at temperatures lower than the freezing point of the water. The ice formed on the surface is detrimental both to the thermal and the energe...

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 eac...

Nowadays, all industry, including the agri-food sector, faces the urgent need to increase its competitiveness in order to survive ina global market. In this context, it is vital to ensure a strong, renewed and innovative industrial base throughout all stagesof thevalue chain, capable of competing internationally and differentiating itself by the qu...

A Data Centre is a physical space that groups together computer equipment such as servers, storage arrays, among other equipment. It can be used for storage, processing and data protection. The majority of data centres operate 24 hours a day, and must provide the user with guarantees in terms of security and performance. Energy consumption is there...

In an increasingly competitivesociety with an unfavourable economic environment, it is necessary for Small and MediumEnterprises (SMEs) to update themselves, thereby increasing their efficiency. Companies increasingly use computational tools tosupport the development of predictive scenarios in order to facilitate decision-making. However,the tools...

Food safety and eradication of food waste are current concerns of society and governments due to health, ethics, and sustainable economics. There are multiple technologies for monitoring food safety at different chain stages, among them, time-temperature integrators (TTI). Temperature is a major factor affecting food quality and safety during its l...

It is widely known that the defrosting operation of evaporators of commercial refrigeration equipment is one of the main causes of inefficiency on these systems. Several defrosting methods are used nowadays, but the most commonly used are still time-controlled defrosting systems, usually by either electric resistive heating or reverse cycle. This h...

It is widely known that defrosting operation on commercial refrigerators is one of the main causes of inefficiency on these systems. Several defrosting methods are used nowadays, but the most commonly used are still time-controlled defrosting, usually by either electric resistive heating or reverse cycle, as most demand defrost methods are usually...

The use of closed refrigerated display cabinets in supermarkets is in progression because of the potential energy saving compared to the open ones with an air infiltration at the front. However, the influence of the presence of doors on product temperatures (determining factor of product quality) is much less studied. For better understanding the i...