Fabio Bozzoli

This paper presents the experimental results of tests carried out on a Flat Plate Pulsating Heat Pipe (FPPHP) during an ESA parabolic flight campaign. The device, designed for further testing aboard the International Space Station, is a plate of 102 mm long by 90 mm wide and 3.5 mm high, engraved with channels of 3x3 mm² and is filled with FC-72 (so above the critical diameter on Earth), with a filling ratio modified each day of flight (between 35% and 65%). The tests were performed in vertical -with horizontal channels (VHC)- position, and with a cooling temperature set at 20°C. First, the visualizations made it possible to distinguish the two types of flow pattern observed between the VHC position and in microgravity condition. Then, while the measurements do not help to demonstrate a clear trend on the influence of the filling ratio on thermal resistance in VHC orientation under normal gravity conditions, it appears that, during microgravity transient conditions, thermal performance is significantly improved with an increase in the filling ratio, the liquid plugs being closer to the evaporator. Finally, the last part deals with the hydraulic and thermodynamic behavior of the plugs-slugs trains through tracking data obtained from well-defined visualizations. The interfaces trajectories provide key information on the liquid and vapor size as well as velocities. Using the momentum equation, pressures are estimated in the bubbles. The mass exchange between liquid and vapor phases is evaluated from the time derivatives of pressure, volume and temperature.

Additive Manufacturing (AM) for jewelry applications is increasingly adopting Binder Jetting (BJ) to overcome the fusion-related limitations associated with precious metals, including unstable melt pools, excessive reflectivity, and high thermal conductivity. In this context, the present review establishes a thermophysical and manufacturability-oriented framework that redefines thermal management beyond localized melt-pool stabilization toward the furnace-scale control of densification kinetics, shrinkage evolution, atmosphere-assisted sintering, and viscoplastic deformation. Particular emphasis is placed on gold-, silver-, and platinum-based jewelry alloys, with a specific focus on the thermal, mechanical, and chemical phenomena governing Binder Jetting sintering. During consolidation, low-density green bodies (~40–65% relative density) must transform into highly dense components through extensive volumetric shrinkage and gravity-driven deformation, creating major challenges in dimensional fidelity and surface quality. The review further examines predictive viscoplastic constitutive models (SOVS/ROH), reversed-deformation compensation strategies, and atmosphere-engineering approaches for oxide reduction, pore-pressure regulation, and residual-porosity control. By linking thermophysical consolidation, dimensional fidelity, polishability, and jewelry-grade manufacturability within a hierarchical framework, this review provides a structured basis for the development of high-precision and low-waste precious-metal additive manufacturing.

Micro heat exchangers (MHXs) have emerged as a critical technology for advanced thermal management in the food and pharmaceutical industries due to their high surface area-to-volume ratios, compact design, and precise temperature control. This review provides a systematic and integrated analysis of MHX technology, covering their fundamental principles, classification, design methodologies, performance enhancement techniques, and industrial applications. Unlike existing reviews, the present work establishes a unified framework that links microscale heat transfer mechanisms, such as Brownian motion, surface corrugation effects, and non-dimensional parameters, with practical design choices, manufacturing routes, and the process requirements specific to food and pharmaceutical systems. The subsequent sections explore the key performance-influencing factors, including channel geometry, surface enhancement strategies, nanofluid utilization, and governing non-dimensional numbers (e.g., Nusselt, Reynolds, and Knudsen numbers), which are systematically compared across different operating regimes. Recent advances in materials and fabrication techniques, such as laser ablation, lithography, micro-milling, embossing, and additive manufacturing, are analyzed with respect to their scalability, thermal–hydraulic performance, and industrial feasibility. Furthermore, the review highlights the emerging trends in micro heat exchanger (MHX) optimization, including computational fluid dynamics (CFD)-driven design, smart monitoring systems, and energy-efficient integration within processing lines. Finally, the paper also identifies the key challenges and limitations of micro heat exchangers, including pressure drop, fouling, scaling, manufacturing complexity, and cost constraints. These are critically discussed along with future research directions aimed at improving reliability and sustainability. By consolidating the dispersed research outcomes into a coherent, design-oriented perspective, this review offers new insights and practical guidance for researchers, engineers, and industry practitioners seeking to advance the deployment of MHXs in food and pharmaceutical processing.

Convection heat transfer enhancement techniques play a vital role in many industrial thermal processing applications, including food thermal processing, and the pharmaceutical, and chemical manufacturing industries. These techniques contribute to reducing the size and cost of heat exchangers, conserving energy, improving product quality, and enhancing both energy efficiency and thermal performance. Among passive solutions, corrugated wall tubes are widely adopted in heat exchangers for such applications. This study applies the inverse heat conduction problem (IHCP) method combined with infrared thermography data to estimate the local temperature and convective heat transfer coefficient distributions for forced convection in a transversally corrugated wall tube with high viscosity fluid flow under laminar conditions. The IHCP is solved within the corrugated wall domain using measured external wall temperatures as input. Thermal performance was evaluated over a Reynolds number range of 290-1200. The findings showed that at Re < 350, irregular local temperature and convective heat transfer distributions led to reduced thermal efficiency, unreliable sterilization, and increased microbial risk, whereas for 650 < Re < 1200, thermal efficiency improved significantly. These findings support the development of more efficient heat exchanger designs, offering significant benefits to industries requiring precise thermal management.

This study investigates the feasibility of establishing a Renewable Energy Community (REC) to improve sustainable and equitable energy access in developing countries. The case study focuses on Gujicha, a rural off-grid village in Ethiopia's Oromia region, where households rely on polluting energy sources such as coal, biomass, and kerosene. These traditional fuels hinder socioeconomic development and pose significant health and environmental risks. The proposed solution involves the design and implementation of a stand-alone photovoltaic system to supply clean energy to a community hub, primarily a school. Simulations were conducted to optimize panel selection, battery storage, and load management strategies, considering system efficiency and lifecycle cost. The design prioritizes energy use during peak solar hours and includes surplus energy recovery to reduce battery dependency. Simulation results under different seasonal conditions confirm that the system ensures stable energy access and supports essential services such as lighting, computing, and medical refrigeration. The inclusion of dynamic load prioritization enhances operational flexibility and resilience. This model demonstrates how RECs can provide longterm benefits in off-grid contexts by fostering energy autonomy, supporting education, and enabling community services. The approach is scalable and adaptable, offering a replicable pathway for sustainable electrification in similar rural environments.

In recent years, interest in lithium-ion batteries has grown significantly due to their dominance in electric mobility, driven by their high energy density. However, their performance and longevity are strongly influenced by the effectiveness of heat dissipation and thermal management. The literature indicates that battery temperature should be maintained within the optimal range of 20–40 °C, while also ensuring minimal temperature gradients within the battery pack. In this study, a thermal management system for electric vehicle batteries which combines two different cooling approaches (i.e., direct immersion cooling and pulsating heat pipes) is presented. In particular, the battery pack is placed inside a PVC case and completely submerged by a low-boiling dielectric fluid (T_bp = 33.4 °C at 1 atm) to take advantage of the excellent thermal properties of the liquid and of the latent heat during phase change. The evaporator section of the pulsating heat pipe is positioned in the vapor phase region of the dielectric fluid, while the condenser section is located outside the PVC box and cooled by an airflow in natural convection. This setup is a completely passive system. To evaluate the cooling performance of the dual two-phase cooling system, tests were conducted on the battery pack at three different discharge C-rates 0.5C, 1C, and 2C that reproduce the working conditions of a real-world battery. To evaluate the effectiveness of the new setup, its performance was compared with cooling based on natural convection and direct immersion cooling alone. These approaches were assessed under two controlled ambient temperatures—5 °C and 20 °C—to compare their performance in varying conditions. The results show that the hybrid system performs particularly well, especially because it can operate passively without requiring external power or active control mechanisms.

Recently, solar energy technologies are a cornerstone of the global effort to transition towards cleaner and more sustainable energy systems. However, in many rural areas of developing countries, unreliable electricity severely impacts healthcare delivery, resulting in reduced medical efficiency and increased risks to patient safety. This review explores the transformative potential of solar energy as a sustainable solution for powering healthcare facilities, reducing dependence on fossil fuels, and improving health outcomes. Consequently, energy harvesting is a vital renewable energy source that captures abundant solar and thermal energy, which can sustain medical centers by ensuring the continuous operation of life-saving equipment, lighting, vaccine refrigeration, sanitation, and waste management. Beyond healthcare, it reduces greenhouse gas emissions, lowers operational costs, and enhances community resilience. To address this issue, the paper reviews critical solar energy technologies, energy storage systems, challenges of energy access, and successful solar energy implementations in rural healthcare systems, providing strategic recommendations to overcome adoption challenges. To fulfill the aims of this study, a focused literature review was conducted, covering publications from 2005 to 2025 in the Scopus, ScienceDirect, MDPI, and Google Scholar databases. With targeted investments, policy support, and community engagement, solar energy can significantly improve healthcare access in underserved regions and contribute to sustainable development.

This study experimentally analyzes the performance of a passive thermal management system using a three-dimensional (3D) pulsating heat pipe (PHP) designed for pouch cell batteries in electric vehicles. The term “3D” refers to the complex spatial arrangement of the PHP, which features multiple interconnected loops arranged in three dimensions to maximize heat dissipation efficiency and improve temperature uniformity around the battery pack. Lithium-ion pouch cells are increasingly favored for compact and lightweight battery packs but managing their heat generation is crucial to maintaining efficiency and preventing failure. This research investigates the operational parameters of a 3D PHP by testing two working fluids (R134a and Opteon-SF33), three filling ratios (30%, 50%, and 80%), and various condenser conditions (natural and forced convection at 5 °C, 20 °C, and 35 °C). The effectiveness of the PHP was tested using simulated battery discharge cycles, with power inputs ranging from 5 to 200 W. The results show that the 3D PHP significantly improves battery thermal management. Additionally, Opteon-SF33, an environmentally friendly refrigerant, offers excellent heat transfer properties, making 3D PHP with this fluid a promising passive cooling solution for electric vehicle batteries.