Journal of Thermal Analysis and Calorimetry最新文献

The growing demand for energy-efficient automotive air-conditioning (AAC) systems has highlighted the need for advanced lubrication methods to improve performance and reduce fuel consumption. Despite many advancements, more lubrication system technologies (e.g. nano-lubricants) need to be developed to achieve effective thermal and tribological performance, especially in actual automobile systems. Thus, the need for this research is to analyse various nano-lubricant formulations and evaluate its thermal and tribological performance in real-world working conditions. The effect of different compositions of the nano-lubricant on the cooling capacity, compressor power consumed, and the coefficient of performance of the system is tested in a test rig. Predictive modelling of the system is designed using a deep echo state network (ESN), and the optimization of the nano-lubricant formulation is performed using an artificial satellite search algorithm, which uses data generated during tests to optimize the formulation for maximum overall efficiency. The results show that the hybrid nano-lubricant (CuO–TiO₂/PVE composite) improves system characteristics, such as a 40.23% reduction in the friction coefficient and 23% reduction in wear scar diameter. Besides other factors, the compressor efficiencies are increased by 15–20%, the power consumptions are decreased by 8–10% and the cooling loads are increased by 12% while 1% of nanoparticles are used with PVE. These features are important factors for automotive applications and present an opportunity for the automotive industry. The results suggest that nanoparticles could be an effective means to improve the life and efficiency of AAC systems and hence could be used in the refrigeration system of a vehicle to improve the performance.

An integrated system for the SPT plant was created in this work consisting recuperative organic Rankine cycle (RORC) as the bottoming cycle, whereas the helium Brayton cycle (HBC) was regarded as the topping cycle. Engineering equation solver software was used to do the energy, exergy, exergoeconomic analysis, and working fluid selection of the suggested system. In comparison to the traditional solar plant (SPT-HBC), it was determined that the suggested solar power plant (SPT-HBC-RORC) had an energy and exergy efficiency improvement of 19.86% and 19.85%, respectively. However, there was a 9.41% increase in the overall cost of the plant. Lastly, the energy, exergy efficiency, and levelized cost of electricity (LCOE) values of the proposed solar power plant were 34.45%, 36.89%, and 43.23 $MWh⁻¹, respectively. The best fluids in terms of thermodynamics and economy were proposed to be R1233zd(E) and R1336mzz(Z), respectively. The suggested solar power plant outperformed supercritical CO₂ power generating systems and SPT-based Rankine cycles, according to a comparison with earlier research.

Hybrid Organic Rankine Cycle (ORC) systems provide a promising pathway for improving low-grade heat recovery, especially when integrating renewable sources such as solar thermal energy and biomass. This study presents a thermodynamic analysis of a hybrid ORC employing advanced zeotropic mixtures enhanced with nanoparticles to improve heat absorption and cycle performance. Three environmentally friendly HFO-based zeotropic mixtures were evaluated in Aspen Plus, combined with TiO₂, ZnO, and Ag nanoparticles at varying mass fractions (ϕ = 0.0001–0.1). The results indicate that temperature glide matching in the zeotropic mixtures significantly improved evaporator heat transfer and reduced irreversibility. Among the nanoparticles examined, Ag demonstrated the highest thermal enhancement, achieving an efficiency of up to 10.77% and a 12.3% increase in net power output at ϕ = 0.01. Higher nanoparticle mass fractions (ϕ = 0.1), however, resulted in reduced performance due to increased viscosity and agglomeration effects. The hybrid solar–biomass configuration provided improved thermal stability and continuous operation under fluctuating environmental conditions. Overall, the findings highlight the potential of combining zeotropic mixtures with optimally dispersed nanofluids to enhance the performance and stability of hybrid ORC systems for sustainable low-temperature power generation.

This study investigates thermal lag in non-isothermal differential scanning calorimetry (DSC) measurements, focusing solely on sample-centric contributions and excluding thermal events. By comparing indium (a good thermal conductor) and ammonium perchlorate (a poor thermal conductor) at varying heating rates, it is demonstrated that poorly conductive materials develop nonlinear temperature gradients within the sample, which are amplified by increased heating rates. In contrast, the indium sample exhibits a linear temperature profile that remains largely independent of heating rate under typical experimental conditions, consistent with Fourier’s law for steady-state or isothermal conditions. This observed material-dependent difference in thermalization behavior suggests that temperature calibration using an indium standard may be insufficient for accurately correcting thermal lag in non-metallic samples. Furthermore, there is no guarantee that temperature errors arising from such commonly studied materials can be fully mitigated through experimental controls alone, although employing moderate heating rates appears to be an effective strategy.

Graphical abstract

The present study uses carboxymethyl cellulose (CMC)-based non-Newtonian fluid to investigate the friction factor, heat transfer, and thermal performance factor (TPF) for a shell and helical tube heat exchanger (SHTHE) with helical inserts. Three distinct concentrations of CMC (0.2%, 0.3%, and 0.4%) were added to distilled water. They were made to flow inside the helical tube at different flow rates with three helical inserts of different pitch. The analysis showed that as the CMC concentration and pitch of the helical insert increases the heat transfer rate decreases. The highest Nusselt number was obtained with 2 mm pitch helical inserts at a concentration of 0.2% (by mass) CMC-based non-Newtonian fluid, while the lowest was observed with 6 mm pitch helical inserts at a 0.4% (by mass) CMC concentration. Furthermore, the friction factors increased with increasing CMC concentration and decreasing the pitch of the helical insert. Nearly, all combinations exhibited a thermal performance factor (TPF) greater than unity. The results showed a maximum TPF value of 1.29 for 2 mm pitch helical inserts with a 0.2% (by mass) concentration of CMC-based non-Newtonian fluid, confirming that employing inserts to the system is beneficial, despite resulting in increased pressure drop.

Global photovoltaic (PV) technologies are increasingly challenged by efficiency degradation caused by high operating temperatures, making effective temperature control crucial to maintaining optimal power generation. To address this issue, this paper presents a comprehensive review of recent advancements in passive cooling technologies for PV panels, highlighting the potential of methods that require no external energy input to enhance performance and ensure engineering feasibility. The study systematically analyzes five mainstream approaches—water cooling, heat pipes, phase change materials, ribbed surface heat transfer, and biomimetic cooling—demonstrating how each technique leverages distinct physical mechanisms to lower PV module temperatures. This temperature reduction leads to improved energy conversion efficiency and shows promise in reducing the levelized cost of electricity. Despite these benefits, the widespread commercial adoption of passive cooling technologies still faces significant hurdles, including high material costs, limited durability, and variable environmental adaptability. This review offers valuable insights into the selection and implementation of effective PV passive cooling strategies and outlines future directions for research and development. In particular, progress in novel materials, system integration, and intelligent thermal regulation is expected to be central to future breakthroughs, contributing to the sustainable evolution of PV technology.

Calorimetry-based disease diagnosis is increasingly positioned as a promising noninvasive tool that can complement clinical data. During recent years, the complex calorimetric profiles reflecting the thermal unfolding of blood plasma proteins and the thermal stability of the plasma proteome have been proved to distinguish between the healthy state and a number of pathologies. More details in the complexity of calorimetric profiles and discovering of reliable specific calorimetric markers can be achieved by the use of different mathematical routines that allow building models for differentiation of disease from healthy conditions. In this work, we applied intercriteria analysis (ICrA) and identified an ICrA-based set of specific intercriteria dependences, underpinning key relationships across the calorimetric dataset. The findings strongly suggest that immunoglobulins are the predominant drivers of the evaluated interdependencies.

In one of the most recent advances aimed at enhancing the thermal inertia of building structures, the integration of phase change materials (PCMs) into the roofing system has demonstrated a significant impact on reducing internal temperature fluctuations and overall energy transfer to indoor spaces. This study evaluates the effectiveness of PCM layers incorporated into building roofs, focusing on their performance at three different positions and across varying thicknesses, specifically under the warm and humid climatic conditions of Silchar, India. The objective is to minimize the heat gain into the interior and lower the internal surface temperature, thereby improving indoor thermal comfort. The numerical study, which is conducted with and without the presence of PCM, reveals that a 20-mm-thick PCM layer can significantly reduce the overall energy transfer to the interior by 63.23%. The most effective configuration is found when the PCM is positioned between two reinforced concrete layers near the bottom layer, which results in the lowest heat flux. Additionally, this configuration reduces the peak temperature by 7 °C and provides a substantial time lag of 3 h to reach the maximum average roof temperature, featuring its potential for passive thermal regulation.

In extremely cold climates, multilayered clothing systems are essential for maintaining both physiological comfort and thermal protection. The principles, components, and performance traits of multilayered clothing are thoroughly examined in this review, with a focus on breathability, moisture management, and thermal insulation. Wearer safety and comfort are directly impacted by the way the base, mid, and outer layers of fabric interact to determine overall heat retention and vapor transmission. Additionally, the study investigates the effects of fiber composition, fabric structure, and cutting-edge material technologies such as phase-change materials (PCMs), aerogels, and sophisticated nonwovens. The efficiency of multilayered ensembles in dynamic activity-based and environmental settings is also examined. The results emphasize the need to optimize layer combinations in order to reduce heat loss and cold stress by striking a balance between moisture regulation and thermal insulation. Incorporating current developments in textile engineering and human thermoregulation research, this review offers a scientific basis for creating high-performance cold weather clothing.

Graphical Abstract

The numerous effects on thermophysiological comfort in multilayered garment systems in cold weather are depicted in this illustration. The heat and moisture balance at the skin–clothing–environment interface is determined by the interaction of important external environmental factors like air temperature, humidity, solar radiation and wind speed, as well as clothing properties (air permeability, moisture management, and thermal insulation) and human physiological activity.

In order to maximize the performance of cold weather clothing, the Figure highlights the dynamic interaction between human factors, clothing systems, and environmental stressors.

With the rapid advancement of microelectronic technology, traditional cooling methods are increasingly unable to meet the thermal dissipation demands under high heat flux densities. The compact design and enhanced thermal performance of microchannel heat sinks (MCHSs) have made them a promising solution for efficient thermal management. This review summarized recent progress in enhancing MCHS performance through structural optimization, biomimetic design, and nanofluids augmentation. Modifications to microchannel geometry, incorporation of cavities and ribbed structures, and multilayered channel configurations have been shown to effectively expand the heat transfer area and induce flow disturbances. Inspired by natural structures such as leaf veins, honeycombs, and spiderwebs, biomimetic designs further improve temperature uniformity and flow characteristics. Concurrently, nanofluids, owing to their high thermal conductivity and Brownian motion effects, are widely utilized for heat transfer enhancement, though challenges related to increased viscosity and stability persist. The synergistic integration of biomimetic architectures with nanofluids demonstrates superior thermal performance, achieving an optimized balance among heat transfer coefficient, pressure drop, and temperature uniformity. Finally, this paper outlined future directions including adaptive cooling with hydrogels, artificial intelligence-driven optimization, and sustainable manufacturing, offering theoretical insights for next-generation thermal management systems in high-power electronic devices.