The development of passive temperature management in zero-energy consumption is of great significance for coping with the global energy and environmental crisis, and it has great potential to preserve food quality. Here, inspired by the guttation and evaporative cooling of plant leaves, an entangled porous hydrogel was synthesized by copolymerization of N-isopropylacrylamide (NIPAM) and butyl acrylate (BA) through a cross-linker-free strategy. The extremely low content of initiator led to sufficiently long chains and an entangled structure, maintaining the strong mechanical property of water-swollen hydrogels. The hydrogels were transparent at room temperature with visible transmittance higher than 84.90%, and they turned white at a high temperature with an average reflectance higher than 43.45% in the solar spectrum. The reversible transparency alteration brought a solar transmittance modulation of >63.92% and solar reflectance modulation of >43.99%. And the swollen hydrogels had a high emissivity (>93.05%) in the atmospheric windows. Due to the constricted network, free water was squeezed, and the water layer appeared on the hydrogel surface in a white mode, improving the water evaporation performance. Based on the integration of spectrum modulation, water evaporation, and radiative cooling, the hydrogels could achieve subambient temperatures under strong sunlight irradiance, showing a temperature difference of ∼6 °C in an outdoor experiment. Furthermore, the hydrogels preserved the pear quality by avoiding the sunburn damage and maintained a quality close to fresh samples. The cross-linker-free polymerization offered a feasible solution to improve the passive temperature management performance, and its enhanced mechanical properties also broaden application scenarios.

Multi-objective experimentation and optimization of multi-tube evaporative cooler with Maisotsenko cycle using genetic algorithm

This paper focuses on the simulation in SolidWorks and experimental study of a mobile solar air cooler using clay as the base material. This device is an energy-autonomous and economically viable response to the challenges of climate change and limited access to conventional air conditioning in developing countries. The methodology used incorporates specifications and the optimal choice of components necessary for the prototype (clay, a 1 W DC fan, four 500 Wp photovoltaic panels with a 2 kVA / 1.6 kW 48 ,V converter and a 48 V 200 Ah battery bank)as well as the experimental characterisation of the prototype. The results show a temperature reduction of 5 C (indoor temperature of 25C for 30 C outdoors) with relative humidity of 55%, autonomy of one day and daily consumption of 7 kWh. The cost of producing the device is 221,500 CFA francs.

Abstract. This work addresses the limitations of traditional air conditioners (AC) by incorporating an innovative design for DC air conditioners, optimizing energy resources, developing an adaptive feedforward incremental conductance (FFINC) algorithm, and validating the approach through experiments and a cost-benefit analysis. The proposed AC is designed to effectively regulate moisture levels within a room, utilizing an innovative structure that circulates comfortable air throughout the room. This design serves as a promising alternative to traditional air conditioning systems. The authors have developed a solar air cooler suitable for the modern era that can either replace AC units under specific conditions or reduce their number when operating in hybrid mode. Proposed design maintains a distance of 3 cm between the water circulation area and the DC fan to optimize air cooling efficiency. The system includes a 60 W DC fan that draws cool air containing water, which passes through a water absorber filter. Moreover, a 50 W dehumidifier inside the air cooler effectively controls room humidity, ensuring that the air remains dry and comfortable. By absorbing excess moisture, the dehumidifier enhances the overall cooling performance of the system, contributing to improved air quality and comfort for occupants. A 20 W DC water pump and the DC fan use energy from various electrical sources. Under sunny conditions, a solar panel, connected via a DC to DC zeta converter, provides power to the DC air cooler. During cloudy weather or nighttime, an AC to DC converter is used to optimize operation in emergency situations; a battery is available to ensure uninterrupted operation.

Purpose Several studies were done to replace toxic and pollutant anticorrosive pigments and solvents with more environmentally friendly compounds. As a result, chromate and lead-based inhibitors were replaced by zinc phosphate and organic solvents were replaced by water. Besides, because of concerns related to zinc phosphate, other anticorrosive pigments were proposed. However, not many studies were done related to the use, as a solvent, of different types of water. The purpose of this study is to study the replacement of distilled water in anticorrosive water-borne paints by wastewater from cleaning paint industry utensils, from air coolers or by rainwater. Design/methodology/approach In a first step, the waters were characterized by physicochemical determinations (total solid dried, pH, conductivity, hardness) and chloride content. Besides, electrochemical tests were done on SAE 1010 steel immersed in the different waters with and without an anticorrosive pigment suspended to study the effect of water composition on substrate corrosion. Tap and distilled water were used as controls. In a second step, anticorrosive paints containing the different waters were prepared, applied and tested by electrochemical tests such as corrosion potential measurements and polarization resistance determinations and by exposure in humidity and salt spray chambers. Findings Results show that the characteristics of the water are not so relevant when they are incorporated in paints, and this fact enhances the use of wastewaters, replacing distilled water in water-borne paints. Originality/value Results of the electrochemical tests on SAE 1010 steel immersed in the different waters with and without an anticorrosive pigment suspended showed that the selected waters have different aggressiveness against steel, enhancing or diminishing the protection afforded by the anticorrosive pigment. However, once incorporated in the paint, the type of water used as a solvent is not so relevant in the coating’s protective behavior. The paints prepared by using wastewaters protected steel (until 888 h in the humidity chamber and 720 h in the salt spray cabinet) as good as distilled water anticorrosive paints; the use of these waters in anticorrosive paints could be an ecological opportunity to save clean water and reuse wastes.

Defrost cycles in shipboard refrigeration plants are typically initiated on fixed schedules or by operator judgement, which can lead to unnecessary energy use and temperature variability during the transport of frozen products. This study proposes a data-driven predictive maintenance approach to trigger defrost on demand in a merchant reefer vessel carrying frozen tuna. A total of 76,692 operational records from cargo-hold air coolers and holds were analysed, including delivery and return air temperatures, hold air temperature and relative humidity. The records were modelled to show their behaviour under real voyage conditions. The modelled strategy indicates that 66.55% of defrost cycles performed during the study period were unnecessary, suggesting substantial scope to reduce defrost frequency and associated disturbances. These findings demonstrate the feasibility of implementing machine learning (ML)-based decision support for maritime refrigeration. This enables defrost-on-demand scheduling, which has the potential to enhance operational efficiency while supporting product quality, sustainability and traceability in the frozen tuna supply chain.

A dew-point evaporative air cooler incorporating a novel segmented heat exchange design, demarcated according to the humidity state of moist air, is proposed. The system employs a porous fibrous material to create a wetted evaporative surface, which is continuously maintained in a moistened condition through a self-wicking water supply mechanism to enhance latent heat transfer. Circular fins are installed on the heat exchanger’s partition surface once the moist air reaches saturation, thereby improving sensible heat exchange between the dry and wet channels. The performance of a prototype was evaluated under controlled conditions in a standard enthalpy chamber. Experimental results indicate that, under typical summer conditions (inlet dry-bulb and wet-bulb temperatures of 33.8 °C and 25.4 °C, respectively), with an air mass flow ratio of 0.7 and an air velocity of 1.5 m/s, the wet-bulb effectiveness reaches 114.4% and the dew-point effectiveness achieves 84.8%. The maximum temperature reduction occurs in the sensible heat exchange section, reaching up to 6.1 °C, demonstrating its substantial sensible heat recovery capability. The device exhibits an energy efficiency ratio (EER) ranging from 9.1 to 31.8. The proposed compact configuration not only enhances energy efficiency but also reduces material costs by approximately 15.4%, providing a valuable reference for the future development of dew-point evaporative cooling systems in residential buildings.

This review systematically examines the latest research progress and diverse applications of direct evaporative cooling and indirect evaporative cooling across five core sectors: industrial and energy engineering, the built environment, agriculture and food preservation, transportation and aerospace, and emerging interdisciplinary fields. While existing research often focuses on single application silos, this paper distills two common foundational challenges: climate adaptability and water resource management. Quantitative analysis demonstrates significant performance gains. Hybrid systems in data centers increase annual energy-saving potential by 14% to 41%, while precision root-zone cooling in greenhouses boosts crop yields by 13.22%. Additionally, passive cooling blankets reduce post-harvest losses by up to 45%, and integrated desalination cycles achieve 18.64% lower energy consumption compared to conventional systems. Innovative strategies to overcome humidity bottlenecks include vacuum-assisted membranes, advanced porous materials, and hybrid radiative-evaporative systems. The paper also analyzes sustainable water management through rainwater harvesting, seawater utilization, and atmospheric water capture. Collectively, these advancements provide a comprehensive framework to guide the future development and commercialization of sustainable cooling technologies.

This paper analyses the impact of inlet air precooling on the efficiency and electricity consumption of an open-type evaporative cooling tower. An Indirect Evaporative Cooler (IEC) was used to reduce the inlet air temperature, and its influence on system efficiency was experimentally evaluated. Although IEC units and the Maisotsenko cycle are increasingly discussed in the literature, no research to date has considered their effect on evaporative tower efficiency under actual operating conditions. For this purpose, a test stand was constructed comprising an open cooling tower and an IEC unit. The system operated automatically for 2952 h, corresponding to a full cooling season in Poland. Two sets of data collected during cooling tower operation were analysed: without precooling (Stage I) and with precooling using IEC (Stage II). Measurements were recorded every 10 s. Additionally, tests were conducted at elevated thermal loads and peak ambient temperatures. The comparative analysis concluded that air precooling using IEC reduced the cooling tower’s electricity consumption by approximately 15% and increased the SCOP of the cooling tower by 30%. This demonstrates the significant potential of the proposed solution.

Abstract Evaporative cooling towers are critical solutions to engineering design. Due to the complexity of the heat rejection mechanism and the commonality of the evaporative cooling application, there exists a significant opportunity for efficiency improvements. To mitigate the complexity issue, a model was developed that focuses on the quantification of benefits for efficiency projects. This tool can quantify the reductions in water usage, energy consumption, carbon dioxide emissions, and operational costs for industrial cooling towers for various projects using dynamic, hourly weather data inputs. A validation study using an industrial cooling tower was completed to compare the model and field data. The validation study completed by field data collection showed that the model's emphasis on simplicity does not negatively impact the accuracy of the model's outputs. A distinctive feature of this model is the ability to estimate the tower performance from design parameters and hourly weather conditions through various efficiency projects to the resulting energy, water, carbon dioxide emissions, and cost reductions. Since a cooling tower is a heat rejection device, the cooling capacity is a critical parameter for operation. This parameter was studied through the measured quantities for air discharge temperature, cooling tower fan power, and makeup water flowrate where the model predicts difference values with the field data of 4.3%, 4.7%, and 7.6%, respectively. Another parameter studied was the cooling efficiency, or approach, which the model predicts an average difference of 14% compared to the field data. This is a parameter that is highly dependent on physical design conditions for the cooling tower. Finally, the resultant parameters of the electrical and water consumptions were studied through the fan power and makeup water flowrate, respectively.

Mesoscale Convective Vortices (MCVs) are influential mid-tropospheric systems capable of initiating or enhancing deep convection, yet their role in extreme precipitation over complex terrain remains insufficiently understood. This study examines the dynamical processes leading to the formation and intensification of an MCV associated with the 27 July 2022 heavy rainfall and deadly flash flood in northern Tehran. Using ERA5 data, GPM precipitation estimates, infrared satellite imagery, and Doppler radar observations, we document the multiscale evolution of the event and diagnose the vorticity budget throughout the troposphere. A coherent positive vorticity emerged south of the flood site in the late afternoon and migrated northward as convection intensified. Vorticity-budget diagnostics reveal that all four terms, horizontal advection, vertical advection, divergence (stretching), and tilting, made non-negligible contributions to the local vorticity tendency. Horizontal advection dominated the early development of the MCV, producing positive vorticity tendencies of order 10⁻⁸ s⁻² in the 700–600 hPa layer roughly three hours before rainfall onset. Divergence and tilting further amplified cyclonic vorticity below ~ 700 hPa, with tilting peaking near 850 hPa as strong vertical shear strengthened horizontal vorticity conversion. In contrast, vertical advection acted persistently as a compensating term, partially offsetting the low-level vorticity growth. The combined effect of these processes was a vertically coherent vortex column, aligned temporally with radar-observed convective organization. The extreme rainfall resulted from the interaction between a warm, humid monsoonal inflow from lower latitudes and a cooler air mass advected from higher latitudes, which enhanced low-level convergence, mesoscale ascent, and vortex stretching. This dynamically driven coupling between synoptic forcing, mesoscale vorticity generation, and complex topography produced an unexpectedly intense convective system. The findings highlight the importance of MCV-related vorticity processes in triggering high-impact precipitation events in mountainous mid-latitude regions and underscore the need for improved representation of these mechanisms in forecasting systems.

ABSTRACT This study investigates the influence of cooling rate and temperature on the variant selection of a Mo-rich Ti–6Al–1V–4Mo–Si alloy. Microstructural changes were examined through optical microscopy (OM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). Air cooling (AC) and furnace cooling (FC) were employed to change the cooling rate after heat treatment at 850°C and 950°C. The results reveal that faster cooling promotes the growth of selective α variants and thinner colonies, resulting in a strong transformation texture with certain variant being the most favoured under AC at both 850°C and 950°C. Conversely, slower cooling enables random variant growth with intersecting laths, yielding a more uniform distribution of the 12 possible α variants and a weaker texture. EBSD analyses reveal that α-variant selection at β-grain boundaries can be categorised into three distinct behaviours (Types I, II, and III), providing a unified framework for understanding the mechanisms governing variant selection. This study highlights the critical impact of thermal processing parameters on microstructural characteristics, providing insights on the effect of Mo on phase transformation.

The impact of forging and heat treatment processes on cold compressive and tribological properties (wear rate & friction coefficient) of Ti-6Al-3Mo-2Sn-2Zr-2Nb-1.5Cr-0.1Si (TC21) alloy was studied. Additionally, an investigation of worn surface texture using the Abbott Firestone curve was conducted on MATLAB and Gwyddion software. For 20min, the samples were heated to 925°C. They were then cooled at different rates using water quenching (WQ), air cooling (AC), and furnace cooling (FC). Following that, the samples were aged for four hours at 600°C. The microstructure consists of retained β-phase (βr), secondary α-phase (αs), and primary α-phase (αp). The αs-phase precipitated within the βr-phase in the case of aged samples and solutions treated with AC. The results show that the highest ultimate compressive strength of 1997MPa was obtained for the FC + Aging and the sample owing to the existence of a high-volume fraction of αp-phase in the structure. On the other hand, the lowest ultimate compressive strength of 1473MPa was achieved for the AC sample due to having a high amount of fine αs-phase. Comparing the WQ and WQ + Aging conditions, it is clear that the WQ + Aging condition shows 51% enhancement in wear property due to the presence of the αs-phase after applying the aging process. On the other hand, the wear properties of AC and FC after the aging process improve by only 18% and 4%, respectively. There is a slight variation in the friction coefficient values after the solution treatment process at different cooling rates (WQ, AC & FC). However, after applying the aging process, there is a clear change in WQ + Aging and AC + Aging conditions, where the value of the friction coefficient decreases by 19% and 12%, respectively. For the Abbott Firestone technique, the forged sample has a lower percentage of exploitation zone (77%) and a larger percentage of high peaks (22%). On the contrary, FC and FC + Aging samples have a higher percentage of exploitation zone (81%) and a lower percentage of high peaks (17%) compared to other samples.

The cooling performances of the indirect dry air cooling tower depend on the performance of each section. In accordance with relevant design criteria and standards, the influence of crosswind on the cooling performance of the indirect dry air cooling tower has been fully taken into consideration; however, the differences among sections have not been considered. In summer, the outlet water temperature of one or several sections may be higher than the design value, which will lead to a reduction in the cooling performance of the entire dry air cooling tower. In winter, due to crosswind, the water temperature in the heat exchanger of one or several sections may drop below zero, which means the circulating water pipes could be damaged. Therefore, studying the influence of crosswind on each section of the indirect dry air cooling tower is of great importance for power plant design. In this paper, an indirect dry air cooling tower equipped with flue gas desulfurization and dust removal systems was numerically studied using Fluent software. This cooling tower will be applied in a 2×660MW coal-fired power plant. The flow fields around the cooling tower are presented, and the outlet water temperature of each section is analyzed. The analysis results show that the outlet water temperature is lower when sections face the windward or leeward direction, while it is higher when sections face the side direction. The research results can provide references for engineering measures related to water distribution in summer and anti-freezing in winter.

There exists a long‐standing challenge on how to cool down the heat released from a lithium‐ion battery. Usually researchers adopted expensive techniques for battery cooling. This study attempts to propose an ambient cooling model using electrochemical and thermodynamic principles to address this issue. A standard lithium‐ion battery is used. This battery is based on nickel–cobalt–aluminum oxide (NCA) cathode material which is known to have high energy density. This study calculates heat generation during the charging process and installs an air coolant to control cell temperature. The battery is positioned in an air‐flowing compartment of a battery pack. Thermal analysis demonstrates superior temperature control, with approximately a 29.34% reduction in temperature compared to a commercial battery. Air coolant velocity contributes to more efficient cooling from the periphery to the center, depicting a gradient of temperature from 331 K to 335 K. Additionally, the specific capacity was improved by roughly 7.63%, followed by a gradual voltage increment of 1.16% compared to commercial LIBs. During the charging period, specific energy and power densities increase by approximately 14.09% and 67.55%, respectively, compared to previous cells. These findings highlight the superior temperature control, enhancement of cell performances, and thermal safety of LIBs.

Latent heat cold storage integrated direct evaporative cooler: A neoteric practical design for energy and water saving potential with thermal comfort improvement

Material selection and thermal performance study of a seawater-based indirect evaporative cooler for marine vessel air-conditioning

Towards reliable model validation of evaporative coolers: Unified terminology and benchmark datasets

Artificial neural network-assisted multi-objective optimization of perforated counter-flow regenerative evaporative coolers using enhanced NSGA-II

Fabrication of Solar Powered Air Cooler from household materials