Search

Preparation of atomic Bose–Einstein condensate (BEC) with tunable interactions in a quasi-one-dimensional (quasi-1D) optical trap is essential for both the observation of bright matter-wave solitons and the quantum simulation based on the discrete atomic momentum states. However, the quasi-1D BEC has been obtained by a complex process, which includes the creation of a three-dimensional BEC and its adiabatic transform into a quasi-1D trap. Here, we report the direct creation of a quasi-1D BEC of 133 Cs atoms by the fast evaporative cooling of ultracold atoms prepared by the degenerated Raman sideband cooling. We produce the pure BEC of up to 5.5 × 10 4 atoms in a quasi-1D optical trap with an evaporative time of 6 s. We demonstrate the anisotropic expansion of the atomic cloud after the release from the quasi-1D trap and study the dependence of both the phase space density and the temperature on the number of atoms in the trap during the evaporative cooling. Our study facilitates the promising applications of quasi-1D interacting atomic gases. [ABSTRACT FROM AUTHOR]

Recent escalating interest in the development of highly maneuverable hypersonic vehicles demands sharp leading edges. However, sharp leading edges induce severe aerothermal conditions where conventional passive or ablative thermal protection systems fail to protect the leading edge. Here, we numerically demonstrate transpiration cooling employing oxide coolants as a new alternative system to thermally protect sharp leading edges. We parametrically characterize the performance of transpiration cooling for various coolant properties, flight conditions, and leading edge radii using a semi-analytic boundary-layer model validated with third-order direct numerical simulations. We further utilize direct numerical simulation to examine the impact of the thermochemical behavior of oxide vapors with the external hypersonic flow on transpiration cooling. Our findings do not readily align with an optimal set of material properties for transpiration cooling. Instead, certain coolant properties are more appropriate for various flight conditions and leading edge sizes. Our results also demonstrate that the thermochemical interactions between the oxide vapors and the external hypersonic flow have a negligible impact on the performance of transpiration cooling. Our study provides numerical frameworks to evaluate the performance of transpiration cooling and optimize the coolant properties for various flight conditions to protect sharp leading edges, which are paramount across hypersonic applications.

Passive cooling technologies being free from additional energy consumption, offer significant advantages in reducing carbon emissions and mitigating global warming. However, radiative cooling has a thermodynamic limit, and evaporative cooling requires additional components, which restricts their large‐scale application, respectively. Herein, a radiative/evaporative bifunctional cooling bilayer is presented, featuring an upper layer composed of poly(vinylidene fluoride‐cohexafluoropropene) [P(VdF‐HFP)] integrated with a hygroscopic hydrogel lower layer [polyacrylamide (PAAm)/alginate‐CaCl2]. High solar reflectance (0.916) and long‐wave infrared emittance (0.900) of the P(VdF‐HFP) combined with hydrogel evaporation enable a notable 15.4 °C temperature drop under 706.3 W·m−2 solar radiation. The bilayer is demonstrated to be effective under outdoor conditions for continuous three cloudy days, achieving an average temperature reduction ranging from 6.3 to 15.7 °C. Considering the low cost and simplicity of the preparation method, ease of large‐scale fabrication, and good cooling performance, this bilayer structure provides a promising strategy for the application of passive cooling. [ABSTRACT FROM AUTHOR]

• The countercurrent hollow fiber membrane module is proposed for cold water generation. • A 3-D numerical model is developed accounting for irregular fiber filling. • Channeling effect and flow dead zones degrade the heat and moisture transport. • Irregular fiber filling increases the air side heat transfer resistance by >158 %. • Irregular fiber filling offers the potential to improve energy efficiency under certain conditions. The countercurrent hollow fiber membrane-based evaporative water cooler (MEWC) offers an eco-friendly and compact solution for cold water generation. This study introduces a random sequential addition algorithm to model the real-world irregular fiber filling within the MEWC. Inspired by the honeycomb structure, the developed 3-D numerical model adopts a calculation unit featuring a hexagonal prism comprising multiple fibers. Validation against experimental data reveals an average relative error of 2.81 % concerning outlet water temperature. The effects of fiber filling patterns (regular layout and random layout) on the velocity and temperature fields of the MEWC are investigated. Comparisons of outlet water temperature, cooling efficiency, consumptive electric power ratio, and heat and mass transfer resistance composition between these layouts under various operating conditions are conducted. The results indicate that the random layout fosters severe channeling effect and large flow dead zones, impairing air side heat and moisture transfer. The random layout exhibits over 15.9 % reduction in cooling efficiency and 36.3 % decrease in consumptive electric power ratio compared to the regular layout. Irregular fiber filling leads to a notable 158.6 % increase in air side heat transfer resistance and a 35.9 % rise in mass transfer resistance. Although irregular filling compromises the cooling performance, it demonstrates potential for energy savings under certain conditions. Design schemes should be carefully tailored to meet specific application requirements by considering these trade-offs. [ABSTRACT FROM AUTHOR]

• A solid desiccant cooling system is optimised using a response surface methodology. • Regression models were developed and showed commendable predictive capability. • Multi-objective optimisation was achieved by considering four key parameters. • Case studies demonstrated the system's applicability in Australian climates. Solid desiccant-assisted dew-point indirect evaporative cooling (SD-DPIEC) systems have gained considerable attention as a potential eco-friendly alternative to vapour-compression cooling systems in building cooling applications. However, one major drawback of these systems is their substantial water consumption during evaporative cooling. To tackle this issue, this study aims to improve the cooling efficiency and water utilisation of an SD-DPIEC system using response surface methodology (RSM). This research focuses on optimising four key parameters: supply air temperature, humidity ratio, water consumption rate and coefficient of performance (COP). The independent variables encompass the ambient temperature, relative humidity, regeneration temperature, and recirculation air ratio. Employing a multi-objective optimisation approach via the desirability function, the optimised SD-DPIEC system is subsequently tested in two prevalent weather patterns in Australia. The results demonstrated that the regression models derived from RSM exhibited commendable predictive capability, with the determination coefficient R 2 and Adequate Precision exceeding 0.97 and 40.46, respectively. The outcomes revealed that the system attained its optimal performance with a supply air temperature of 20.36 °C, humidity ratio of 12.56 g kg-1, a water consumption rate of 3.11 kg/hr, and COP of 2.03 under the ambient temperature of 33.79 °C, relative humidity of 68.48 %, regeneration temperature of 51.78 °C, and recirculation air ratio of 60 %. Based on the optimisation results, a case study was undertaken to evaluate the system's applicability in representative Australian climates. The results demonstrated that the system could uphold air conditions with the supply air temperature below 19 °C and humidity ratio below 11.51 g kg-1 under the studied Australian climates. [ABSTRACT FROM AUTHOR]

The thermosyphon heat exchanger contributes significantly to the improvement of energy conservation technology and has been used in multiple applications, raising the possibility of further studies to contribute to increasing the efficiency of heat pipes. This experimental study examines the different filling ratios of pure Acetone liquid inside a WHPHE integrated with the double‐effect of evaporative cooling to improve the energy‐saving technology. This work studies changing the filling ratio of pure acetone working fluid to investigate the effect of the filling ratio on heat exchanger performance in waste energy recovery technology. The heat exchanger was used with four rows and five tubes per row arranged in a staggered manner. The filling ratio of acetone inside the heat pipe was changed from 50% to 100%. The effect of the mass flow rate of air flowing in direct evaporative cooling on energy conservation technology was studied while the mass flow rate of air through indirect cooling remains constant in addition to the effect of ambient temperature. The results showed that the best filling percentage was between 80% at different temperatures, and the highest energy recovery percentage was when it was at the filling percentage of 80% in the presence of evaporative cooling. [ABSTRACT FROM AUTHOR]

The cooling energy consumed by HVAC systems is continuously increasing. This can be attributed to climate changes and greater comfort expectations. Technical solutions are required to reduce cooling energy while maintaining the same level of comfort. The application of indirect evaporative cooling (IEC) can significantly decrease the cooling energy demand of existing air handling systems. The feasibility of implementing this method was examined through a real case study. The system's operation is examined under various heat recovery procedures. Based on the study, the retrofit application of the dry-coil IEC method yields substantial energy benefits. Throughout the study, our goal was to investigate an existing air handling unit (AHU) under actual operational conditions after implementing a direct evaporative cooler and to determine if it leads to a decrease in the demand for mechanical cooling power. This enhancement was attained with minimal adjustments needed in both the control system and technical setup of the AHU. Implementation of the procedure enables a reduction in mechanical cooling peak load, while significantly increasing the useful operating time of the heat recovery and the total obtainable cooling energy. The daily average efficiency of the applicated evaporative cooling was ranged between 72.7% and 72.8%. As a result, the air temperature extracted from the interior decreased by 4.5°C–6.5°C, leading to a boost in the cooling capacity that the heat recovery unit (HRU) can deliver. One of our aims is to draw attention to the importance of moisture transfer within the HRU when conducting energy calculations, as it affects the results. The operational characteristics of the procedure are presented based on results obtained during a torrid day, a hot day, and a summer day. [ABSTRACT FROM AUTHOR]

Evaporative cooling systems have emerged as low-energy consumption alternatives to traditional vapor compression systems for building air conditioning. This study explored the feasibility of utilizing polymeric foamed materials produced through additive manufacturing as wetting materials in evaporative cooling systems. Specifically, two different commercial polylactic acid filaments, each containing a percentage of a chemical blowing agent, were studied. Experiments were designed to evaluate the influence of critical process parameters (line width, flow rate, speed, and layer height) on the performance of the resulting foamed materials in terms of evaporative cooling by conducting water absorption, capillarity, porosity, and wettability tests. Considering that high water absorption, capillarity, and porosity, coupled with an intermediate contact angle, are advantageous for evaporative cooling effectiveness, a low flow rate was found to be the most important parameter to improve these properties' values. The results showed that the appropriate combination of polymer and process parameters allowed the production of foamed polymer-based materials processed by additive manufacturing technology with optimal performance. [ABSTRACT FROM AUTHOR]

This review investigates the role of windcatchers in modern architecture, exploring their optimization through the integration of traditional designs with contemporary technologies. Historically utilized in hot and arid climates for passive cooling, windcatchers offer energy-efficient solutions for improving indoor air quality (IAQ). This study examines the sustainability of traditional windcatcher designs and their relevance in preserving heritage structures. Using advanced tools like computational fluid dynamics (CFD) modeling, modern adaptations of windcatchers can be optimized for urban environments. This review also explores hybrid systems, combining windcatchers with solar chimneys, evaporative cooling, or heat pumps, to enhance performance in low-wind conditions by balancing natural and mechanical ventilation. Additionally, it addresses the role of artificial intelligence (AI) in heritage planning, facilitating the design and integration of windcatchers into contemporary architecture. The findings suggest that windcatchers, combined with modern design strategies and hybrid systems, continue to be viable and sustainable solutions for passive cooling, contributing to energy-efficient and climate-resilient buildings across different environmental and urban contexts. [ABSTRACT FROM AUTHOR]

Recent research has shown that optimizing photosynthetic and stomatal traits holds promise for improved crop performance. However, standard phenotyping tools such as gas exchange systems have limited throughput. In this work, a novel approach based on a bespoke gas exchange chamber allowing combined measurement of the quantum yield of PSII (F q' /F m'), with an estimation of stomatal conductance via thermal imaging was used to phenotype a range of bread wheat (Triticum aestivum L.) genotypes. Using the dual-imaging methods and traditional approaches, we found broad and significant variation in key traits, including photosynthetic CO2 uptake at saturating light and ambient CO2 concentration (A sat), photosynthetic CO2 uptake at saturating light and elevated CO2 concentration (A max), the maximum velocity of Rubisco for carboxylation (V cmax), time for stomatal opening (K i), and leaf evaporative cooling. Anatomical analysis revealed significant variation in flag leaf adaxial stomatal density. Associations between traits highlighted significant relationships between leaf evaporative cooling, leaf stomatal conductance, and F q' /F m', highlighting the importance of stomatal conductance and stomatal rapidity in maintaining optimal leaf temperature for photosynthesis in wheat. Additionally, g smin and g smax were positively associated, indicating that potential combinations of preferable traits (i.e. inherently high g smax, low K i, and maintained leaf evaporative cooling) are present in wheat. This work highlights the effectiveness of thermal imaging in screening dynamic g s in a panel of wheat genotypes. The wide phenotypic variation observed suggested the presence of exploitable genetic variability in bread wheat for dynamic stomatal conductance traits and photosynthetic capacity for targeted optimization within future breeding programmes. [ABSTRACT FROM AUTHOR]

This study presents a review of advances made in evaporative cooling technologies, emphasizing their application in indoor thermal comfort. It highlights that the rising demand for cooling has primarily been met by conventional mechanical vapor compression systems. However, these systems face two significant issues: high electrical energy requirements and the use of refrigerants like chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs), which contribute to ozone layer depletion and global warming. The findings indicate that evaporative cooling technology is a promising alternative due to its low energy demand and potential to integrate renewable energy, therefore enhancing its environmental benefits. The study also details various evaporative cooling technologies, recent improvements in their performance, practical applications, challenges, and opportunities for providing indoor thermal comfort. [ABSTRACT FROM AUTHOR]

Solar heating is important for many applications but less attractive for concepts requiring intermittent heating, such as ionic thermoelectric supercapacitors (ITESCs). However, the heating process even at constant solar illumination can be converted to temperature oscillations through water infiltration and evaporation. Here, this process is demonstrated for a carbon nanotube‐cellulose membrane and used to induce temporally varying temperature gradients across an ITESC, which enables continuous operation through repeated charge and discharge cycles. A temperature variation of 10 K can be generated on the top electrode, which leads to a variation in the temperature difference across the ITESC of 7.5 K. Precise control over charge and discharge durations can be achieved by adjusting the volume and interval of the added water. The concept of temporarily adjusting temperatures by evaporative cooling may be extended to create intermittent heating also for other heat sources that are typically constant. [ABSTRACT FROM AUTHOR]

Evaporative cooling is being re‐evaluated in the context of eco‐systems and environmental friendliness to improve the efficiency of thermoelectric and photovoltaic power generation. One of the essential tasks to improve evaporative cooling performance is the development of materials that can maintain the evaporation path and supply the lost water. Here, we synthesized a macroporous hydrogel by freeze casting at a slow cooling rate. A series of open spaces was designed between the aligned columns of the hydrogel, and water is stably supplied by extensive capillary channels. In a cooling test, it was shown to be effective in reducing the target's equilibrium temperature. As the heat input increased, the cooling effect (that is, the temperature reduction by the hydrogels) tended to increase. In addition, under airflow, the effect was stable, and further enhanced. These results extend design strategies for hydrogel‐based evaporative cooling and offer opportunities to maximize cooling performance by searching for optimal surface shape and exploiting airflow conditions. [ABSTRACT FROM AUTHOR]

Beard and Green compiled one of the earliest reviews on the environmental and societal (cultural) benefits that living turfgrass systems (e.g., home lawns, athletic fields, golf courses, roadsides, and grounds) provide to humans and associated contemporary issues with turfgrass. Today, the benefits of vegetation systems are called ecosystem services, and the associated negative aspects are called disservices. Since 1994, a significant amount of research has been conducted to further understand these ecosystem services and disservices and discover new ecosystem services and disservices, which we summarize and identify the knowledge gaps in this review. Turfgrass systems provide positive economic benefits to the US economy and help increase property values; however, many of these ecosystem services are environmental and societal. Some environmental services include (1) improving soil health, quality, and stability; (2) oxygen production; (3) reducing stormwater runoff; (4) filtering water to protect waterways and recharging groundwater; (5) providing evaporative cooling and reducing sunlight glare to improve human comfort levels; (6) offering vertebrate and invertebrate habitat; and (7) offering solutions for recycling wastewater and biosolids. Some societal (cultural) services include (1) outdoor spaces that improve human mental and physical health, (2) increasing community and social harmony, (3) helping deter crime, and (4) reducing human contact with noxious weeds and human‐disease insect vectors. Research, cooperative extension, and education efforts must be increased on these topics to continue to provide additional evidence of these ecosystem services to the public, policymakers, turfgrass practitioners, homeowners, students, and future generations. Core Ideas: Turfgrass systems are constantly examined for their perceived environmental impacts.Turfgrass systems provide positive contributions (ecosystem services).Turfgrass systems also provide negative aspects (ecosystem disservices).Ecosystem services (benefits) of living turfgrass systems outweigh disservices (detriments).More research is warranted to better understand these services and disservices. Plain Language Summary: Turfgrass systems are living grass systems found in home lawns, sports fields, golf courses, parks, cemeteries, roadsides, and many other spaces. Turfgrass systems provide critical ecosystem services, which are environmental, social (cultural), and economic benefits for humans from vegetation systems. These green spaces enhance soil health and quality, reduce stormwater runoff, and filter and clean water to help recharge groundwater supplies. Like other vegetation, turfgrass systems provide a cooling effect to help enhance human comfort levels and reduce energy use in buildings. Turfgrass systems not only provide a visually nice green space but also help reduce ticks, fleas, and other pests while supporting wildlife habitat. Additionally, turfgrass positively impacts human well‐being, fostering mental and physical health, community relationships, and safety. Continued investigation and outreach are essential to inform policy, management, and public perception. [ABSTRACT FROM AUTHOR]

A quasi-explicit algebraic solution of the problem of quasi-steady water droplet heat- and mass-transfer with condensation or evaporation in a prescribed environment including radiation has been obtained. The solution is based on the mass-fraction form of Fick's law of species diffusive mass transport, which allows accounting for variation in gas density through the diffusion layer surrounding the droplet. A new term, the average vapor supersaturation through the diffusion layer, has been included that allows the model to be extended to environmental conditions significantly outside those for which it is theoretically derived (dilute or near-saturation), even to conditions of relatively high temperature, low relative humidity, and low pressure. The latter two have atmospheric significance because evaporative cooling can induce significant decrease in droplet temperature and possibly induce freezing. Basic modeling assumptions are confirmed by comparison with time-dependent temperature and evaporation-rate measurements of a laboratory laser-heated droplet. Accuracy of the new model is assessed by comparison with exact equations. For temperatures between −30 and 0°C and negligible radiation, relative-error magnitudes in droplet temperature and evaporation rate are less than 5%, even for relative humidity down to 10% and pressure down to 60 kPa. This represents an improvement in accuracy over the conventional model, in which property variations of density and supersaturation through the diffusion layer are not taken into account. Differences in predicted evaporation rates between the mass-fraction and the more common partial-density Fick's laws, which can be significant (>10% above 70% relative humidity) in coupled, implicit equations, are shown to be made negligibly small (<0.5%) by linearizing about the saturation state. [ABSTRACT FROM AUTHOR]

• A novel tubular indirect evaporative cooler is proposed. • A theoretical model is developed and experimentally validated. • Regression models for air treatment performance prediction are established. • Multi-objective optimization with relative weights of output responses is obtained. • The regression models can predict the cooler's performance in diverse climates. Indirect evaporative cooling (IEC) technology is an energy-efficient approach for regulating the indoor thermal environment of buildings. The conventional tubular indirect evaporative cooler (TIEC) may have a relatively low cooling efficiency due to poor wettability issues. The application of moisture-conducting fibers provides a feasible way to solve the above problem. However, the integration of moisture-conducting fibers with TIEC is still in the exploratory stage. This study proposed a novel moisture-conducting fiber-assisted TIEC and conducted a multi-objective optimization. An experimental facility and theoretical model of the proposed moisture-conducting fiber-assisted TIEC were developed. Based on the numerical model validated by experiments and response surface methodology (RSM), the regression models for performance prediction of the cooler were established. Eight input parameters including inlet air parameters, operating parameters and geometric parameters were selected, and four performance evaluation indicators were chosen as output responses. The parameter sensitivity of the regression models was analyzed. The multi-objective optimization was performed by considering the influence of different relative weights assigned to the output responses. Furthermore, the performance of the optimized cooler applied in different climate zones was predicted. The results showed that the product air temperature drop could achieve 8.8–11.3 °C after cooling by the cooler. The established regression models can predict the performance of the moisture-conducting fiber-assisted TIEC conveniently and effectively, which is expected to guide the design and optimization of engineering practices. [ABSTRACT FROM AUTHOR]

Indirect evaporative cooling (IEC), which utilizes natural cooling sources, is an advanced and promising technology to reduce the energy consumption of cooling systems in a data center (DC). This study presents a model of an IEC air-conditioning unit in a DC using TRNSYS simulation software validated using actual operational data to investigate the adaptability of IEC units in data centers located in regions with varying humidity levels, providing a reference for their application and promotion in DCs. Based on this premise, the authors analyzed the meteorological characteristics of Urumqi (a dry region), Beijing (a region with medium humidity), and Shanghai (a region with high humidity), which are representative cities in different humidity zones. The analysis identified the annual operating hours of the unit's three operation modes, including fresh-air indirect heat transfer (FAIHT), IEC, and hybrid. Simultaneously, the authors conducted a simulation of the unit's yearly energy consumption and determined time change curves for annual energy consumption, hourly coefficient of performance (COP) throughout the year, and mechanical cooling in various locations. The results indicate that IEC air-conditioning systems are highly effective in promoting the efficiency of data centers in various humidity regions. Dry locations demonstrate the greatest adaptability, followed by regions with medium humidity and, finally, regions with high humidity. The findings indicate that IEC units provide significant energy efficiency and cost-effectiveness when deployed in typical urban DCs across various humidity zones in China. The average annual power-usage effectiveness (PUE) of each city's DC utilizing the unit is less than 1.3, and the unit's annual operational cost savings exceed 30%. [ABSTRACT FROM AUTHOR]

The green fodder deficit is the biggest bottleneck for livestock productivity in semi-arid regions, especially for resource-poor farmers. Low-cost climate-smart hydroponic chamber (CSHC) based hydroponic fodder production provides a viable solution under such an environment. A CSHC equipped with a fan pad-based evaporative cooling system, controlled drip watering system and smart air exhaust system was designed and developed at ICAR-IGFRI, Jhansi, India with the aim of modifying the inside growth environment of the chamber for improved production of quality fodder. The developed CSHC was capable of maintaining daily average temperature and relative humidity in the range of 23-280C and 87-90%, respectively, with an average cooling efficiency of 78.3%. This efficient cooling was an outcome of specialized CSHC designed with an effective covering material (UV stabilized 200 µm LDPE), shade net with 70% shading efficiency, fan pad-based evaporative cooling system, controlled drip watering system, and smart air exhaust system; which enabled ambient environment conducive for optimum plant growth. Among the different treatment combinations of seed loading rates and soaking hours, the highest maize biomass yield of 2.58 kg/ft2 was achieved after seven days with a seed loading rate of 300 g/ft2 when the seed was soaked for 12 h. At the highest productivity of biomass, the values of dry matter, crude protein, and crude fiber contents were found as 13.51%, 13.71%, and 15.12% respectively. The benefit-cost ratio of the developed CSHC was 1.32 with a payback period of 3.12 years. The developed CSHC was found productive and profitable; hence, it can create a great impact in achieving feed security under resource deficit conditions of climate-change-affected semi-arid regions across the globe. [ABSTRACT FROM AUTHOR]

Outdoor atriums have recently been applied with increasing frequency for natural illumination, but they produce a harsh thermal environment easily in summer. Moreover, overheating of the outdoor atrium necessitates air-conditioning to moderate indoor thermal comfort. Simultaneously, the substantial heat emissions from air-conditioning outdoor units worsen the outdoor thermal environment, creating a vicious cycle. Traditional passive evaporative methods involving water and greenery, while capable of regulating the thermal environment, suffer from low evaporative efficiency and pose significant challenges. To improve thermal environment in outdoor atriums, the spray system was employed due to its high cooling efficiency, especially in open or semi-open spaces. In this study, a comparative experiment was conducted to evaluate the effectiveness of using a spray system for evaporative cooling in open outdoor spaces. Furthermore, employing high-efficiency evaporative cooling through spraying to disrupt the vicious cycle of indoor and outdoor thermal environments. The dual goals include regulating indoor and outdoor thermal conditions while also mitigating the local heat island effect. Temperature and humidity distribution within the atrium and adjacent hallways were monitored, along with the impact on air-conditioning operation consumption in neighboring offices. Results showed that the spray system significantly improved the thermal environment in the outdoor atrium, reducing the average and peak air temperatures by 0.94–2.83 °C and 2.92–5.21 °C, respectively. It also resulted in a drop in the average temperature by 0.56–1.62 °C and the peak temperature by 2.31–3.25 °C in adjacent hallways. This effectively eased the issue of overheating in these areas while raising the comfort level in adjacent office spaces. The predicted mean vote decreased from 1.46 to 0.87, indicating a significant improvement in thermal environment in neighboring offices. Furthermore, the daily energy consumption was reduced by 10.6–12.4% in neighboring offices. This study provided the valuable guidance for improving thermal environments within outdoor atrium. [ABSTRACT FROM AUTHOR]

Aims The survival of inoculated Escherichia coli on Fuji apples in Washington State orchards was studied, considering evaporative cooling, canopy location, year, and region, with the examination of sunlight exposure and inoculation levels in year 2. Methods and results Rifampicin-resistant E. coli was applied to Fuji apples. Initial concentrations for the high-inoculation study were 7.4 ± 0.3 log10 CFU per apple and 3.4 ± 0.3 log10 CFU per apple for the low-inoculation study. Enumeration of E. coli was conducted at 0, 2, 10, 18, 34, 42, 58, 82, 106, and 154 h after inoculation. Results were analyzed using Tukey's honest significance difference test and a log-linear model. Log-linear, Weibull, and biphasic models characterized E. coli die-off patterns for high and low inoculations. The application of evaporative overhead cooling water did not significantly influence E. coli survival on Fuji apples; inoculation level and sunlight exposure were significant factors in a log-linear model. Escherichia coli decreased by 5.5 ± 1.3 and 3.3 ± 0.4 log10 CFU per apple for high and low-inoculated apples, respectively, by 154 h. The biphasic model best explained the die-off pattern for high and low-inoculated Fuji apples. Conclusions Overhead evaporative cooling, a useful fruit quality practice, did not impact the survival of generic E. coli on Fuji apple surfaces. The significant impact of sunlight exposure and inoculation levels on die-off highlights the importance of ultraviolet radiation in risk reduction and the need for various inoculum concentrations in preharvest field studies [ABSTRACT FROM AUTHOR]

• The hybrid cooling and dust suppression solution that prioritizes efficiency, energy saving, and environmental protection has been proposed. • The effects of the hybrid cooling and dust suppression solution in hot fully-mechanized mining face have been conducted by computational fluid dynamics numerical simulation. • The hybrid solution will be of benefit to the improvement of the thermal and clean environment. With the increasing depth of coal mining, the hot and humid environment at the mining faces is becoming more severe. Mining in these conditions, coupled with the hazardous effects of coal dust, poses a significant risk to the health of coal miners. To improve the working conditions in underground coal mines, this study proposes a hybrid solution that combines evaporative cooling and dust suppression in fully mechanized working faces. Numerical models of the mining face are also created to simulate the cooling effects of the proposed solution. Additionally, the migration laws of water droplets from the spray system are also studied. The results indicate that the proposed solution can effectively improve thermal environments and suppress coal dust. This research can enhance the workplace safety in underground coal mines and provide valuable insights for addressing high airflow temperatures and concentrated dust levels. [ABSTRACT FROM AUTHOR]

Copyright of South Architecture / Nanfang Jianzhu is the property of South Architecture Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Enclosed barns can be an effective farming system, providing proper animal welfare conditions to the cattle, with also positive effect on dairy productivity. On the other hand, the air conditioning process can be extremely energy-intensive and expensive, especially during summer months. This is not only due to the high air temperature and the solar irradiance, but also because of the metabolic heat produced by the cattle. The climatic condition considered for this study is the temperate-no dry season-hot summer, typical of northern Italy, where more than 80% of Italian milk is produced. Two conditioning strategies have been evaluated: the traditional chiller with a reverse thermodynamic cycle and an indirect evaporative cooling system based on the Maisotsenko cycle. The two systems were analytically compared considering an enclosed barn with a population of 500 lactating cows, highlighting the pros and cons of each systems. Traditional reverse cycle is capable of consistently reaching the chosen thermo-hygrometric conditions, ensuring the highest dairy productivity. However, this comes at the expense of significant energy expenditure. On the other hand, indirect evaporative cooling is not always able to reach the planned conditions, but it guarantees a significantly lower energy expenditure. [ABSTRACT FROM AUTHOR]

The high surface area of porous media enhances its efficacy for evaporative cooling, however, the evaporation of pure substances often encounters issues including local overheating and unstable heat transfer. To address these challenges, a volume of fluid (VOF) model integrated with a species transport model was developed to predict the evaporation processes of ternary mixtures (water, glycerol, and 1,2-propylene glycol) in porous ceramics in this study. It reveals that the synergistic effects of thermal conduction and convective heat transfer significantly influence the mixtures evaporation, causing the fluctuations in evaporation rates. The obtained result shows a significant increase in water evaporation rates with decreasing the microcolumn size. At a pore size of 30 μm and a porosity of 30%, an optimal balance between capillary forces and flow resistance yields a peak water release rate of 96.0%. Furthermore, decreasing the glycerol content from 70% to 60% enhances water release by 10.6%. The findings in this work propose the approaches to optimize evaporative cooling technologies by controlling the evaporation of mixtures in porous media. [ABSTRACT FROM AUTHOR]

Using adiabatic molecular dynamics coupled with the fluid dynamics equations, we model nucleation in an expanding beam of water vapor and argon on a microsecond scale. The size distribution of clusters, their temperature, and pickup cross sections in dependence on velocity are investigated and compared to the geometric cross sections and the experiment. The clusters are warmer than the expanding gas because of the time scale of relaxation processes. We also suggest that their translational and rotational kinetic energies are modified due to evaporative cooling. The pickup cross sections determined for the final clusters using molecules of the same kind increase with decreasing velocity, still obeying the (a + b N 1 / 3 ) 2 law. [ABSTRACT FROM AUTHOR]

Abstract The vertical tube indirect evaporative cooler (VTIEC) could be preferred one to air-conditioning buildings if its water film quality could be improved. This paper proposed a new VTIEC with inner grooved tubes to improve the water film quality and obtained its performance by experimental method. The results indicated that inner grooved tubes have positive effects on the water film and performance of the new VTIEC. A low working air enthalpy at inlet can significantly improve the total cooling capacity from evaporation, and then VTIEC performance. In this paper conditions, the velocity ratio of 1.52 of the produced air to the working air is better one condition compared to 1.01 and 2.28. The produced air velocity is positive effect on the cooling capacity per unit area until the produced air velocity of about 4.05 m/s and is negative effect on COP. The maximum unit cooling capacity, wet-bulb efficiency and COP are 307.74W/m2, 81.7% and 44.97.The results will promote the application of the new VTIEC.

The present article aims to cover the most recent advancements in heat recovery technology in heating, ventilation, and air conditioning and identify areas that have not been thoroughly investigated. Extensive information is available on heat recovery technologies and exchangers in central systems. Furthermore, the research examines both direct and indirect evaporative cooling approaches. The literature discusses how the heat recovery process is influenced by climatic conditions, air flow rate, and the type of heat exchanger employed. The latest studies contributing to enhancing the performance of heat exchangers were also considered. The results of the study indicate that recent years have witnessed great interest from researchers in the field of lost energy recovery; the experimental, theoretical, and numerical studies have focused on studies of the influencing factors that contribute to improving the performance of the energy recovery process. The current project involves doing an analytical and comparative analysis of the newest research about enhancing the efficiency of thermosyphon heat exchangers and various forms of evaporative cooling.

Abstract Birds maintain some of the highest body temperatures among endothermic animals. Often deemed a selective advantage for heat tolerance, high body temperatures also limits birds’ thermal safety margin before reaching lethal levels. Recent modelling suggests that sustained effort in Arctic birds might be restricted at mild air temperatures, which may require reductions in activity to avoid overheating, with expected negative impacts on reproductive performance. We measured within-individual changes in body temperature in calm birds and then in response to an experimental increase in activity in an outdoor captive population of Arctic, cold-specialised snow buntings (Plectrophenax nivalis), exposed to naturally varying air temperatures (− 15 to 36 °C). Calm buntings exhibited a modal body temperature range from 39.9 to 42.6 °C. However, we detected a significant increase in body temperature within minutes of shifting calm birds to active flight, with strong evidence for a positive effect of air temperature on body temperature (slope = 0.04 °C/ °C). Importantly, by an ambient temperature of 9 °C, flying buntings were already generating body temperatures ≥ 45 °C, approaching the upper thermal limits of organismal performance (45–47 °C). With known limited evaporative heat dissipation capacities in these birds, our results support the recent prediction that free-living buntings operating at maximal sustainable rates will increasingly need to rely on behavioural thermoregulatory strategies to regulate body temperature, to the detriment of nestling growth and survival.

Comparative evaporation rate testing in a dark environment, commonly used to characterize a reduced vaporization enthalpy in interfacial solar evaporators, requires the assumption of equal energy input between cases. However, this assumption is not generally valid, leading to misleading characterization results. Interfacial evaporators yield larger evaporation rates in dark conditions due to enlarged liquid-vapor surface areas, resulting in increased evaporative cooling and larger environmental temperature differentials. Theoretical and experimental evidence is provided, which shows that these temperature differences invalidate the equal energy input assumption. The results indicate that differences in evaporation rates correspond to energy input variations, without requiring enthalpy to be reduced below theoretical values. These findings offer alternative explanations for previous claims of reduced vaporization enthalpy and contradict enthalpy-related conclusions drawn from differential scanning calorimetry. We conclude that postulating a reduced vaporization enthalpy using the dark environment method is inaccurate and that re-evaluation of vaporization enthalpy reduction is required. [ABSTRACT FROM AUTHOR]

Recent years have seen the emergence of new technologies that exploit nanoscale evaporation, ranging from nanoporous membranes for distillation to evaporative cooling in electronics. Despite the increasing depth of fundamental knowledge, there is still a lack of simulation tools capable of capturing the underlying non-equilibrium liquid–vapour phase changes that are critical to these and other such technologies. This work presents a molecular kinetic theory model capable of describing the entire flow field, i.e. the liquid and vapour phases and their interface, while striking a balance between accuracy and computational efficiency. In particular, unlike previous kinetic models based on the isothermal assumption, the proposed model can capture the temperature variations that occur during the evaporation process, yet does not require the computational resources of more complicated mean-field kinetic approaches. We assess the present kinetic model in three test cases: liquid–vapour equilibrium, evaporation into near-vacuum condition, and evaporation into vapour. The results agree well with benchmark solutions, while reducing the simulation time by almost two orders of magnitude on average in the cases studied. The results therefore suggest that this work is a stepping stone towards the development of an accurate and efficient computational approach to optimising the next generation of nanotechnologies based on nanoscale evaporation. [ABSTRACT FROM AUTHOR]

The vertical tube indirect evaporative cooler (VTIEC) could be preferred one to air-conditioning buildings if its water film quality could be improved. This paper proposed a new VTIEC with inner grooved tubes to improve the water film quality and obtained its performance by experimental method. The results indicated that inner grooved tubes have positive effects on the water film and performance of the new VTIEC. A low working air enthalpy at inlet can significantly improve the total cooling capacity from evaporation, and then VTIEC performance. In this paper conditions, the velocity ratio of 1.52 of the produced air to the working air is better one condition compared to 1.01 and 2.28. The produced air velocity is positive effect on the cooling capacity per unit area until the produced air velocity of about 4.05 m/s and is negative effect on COP. The maximum unit cooling capacity, wet-bulb efficiency and COP are 307.74W/m2, 81.7% and 44.97.The results will promote the application of the new VTIEC. [ABSTRACT FROM AUTHOR]

Personal radiative cooling fabrics are a promising zero‐energy solution for creating a cool and comfortable microclimate for outdoor crowds. Despite significant progress, achieving efficient radiative cooling under some extreme situations, such as thermal shock and intensive physical activity, remains a challenge. Herein, a bioinspired metafabric with a dual‐gradient Janus design is reported for personal radiative and evaporative cooling. The hierarchical fiber structure allows for an excellent solar reflectance of 99.4% and mid‐infrared emittance of 0.94, inducing a skin temperature drop of 17.8 °C under intense sunlight. Mesoporous silica nanoparticles fixed in the fibrous network can store evaporative cooling capacity by atmospheric moisture‐absorption in the mild and humid nighttime and release such cooling capacity by moisture‐desorption in the hot daytime, providing an additional skin temperature drop of 2.5 °C. Dual‐gradient Janus design endows the metafabric with an outstanding sweat‐wicking effect and high‐performance sweat evaporative cooling capacity. In the steady‐state evaporation tests, a maximum sweat consumption of only 0.5 ml h−1 can cool the skin to a comfortable temperature, preventing harmful excessive sweating. Additionally, the bioinspired metafabric also possesses favorable wearability and color expansibility. Given these first‐rate features, the bioinspired metafabric will pave the way for the development of advanced functional fabrics. [ABSTRACT FROM AUTHOR]

A solution for solar photovoltaic evaporative cooling and ventilation cavities was proposed to address the bottleneck problems faced by photovoltaic modules in the application of building envelope structures, such as increased working temperature and reduced power generation efficiency caused by photovoltaic module heat generation, as well as their potential impact on building cooling and heating loads. This solution involved installing photovoltaic cells on the surface of the building envelope and keeping a certain distance from the building wall to form a ventilation cavity. At the same time, an evaporative cooling device was arranged on one side of the back panel of the photovoltaic cells. By setting up an outdoor test platform and conducting controlled experiments, the impact of the evaporative cooling effect on the thermal and moisture performance of each component of the solar photovoltaic ventilation cavity and the changes in its electrical properties were studied. Experimental results show that the ventilation cavity with evaporative cooling has a significant cooling effect on the photovoltaic front, photovoltaic backplane, cavity backplane and cavity interior. Compared with the ventilation cavity without evaporative cooling, the average temperatures of these parts are reduced by approximately 3. 7, 7. 6, 4. 5, and 3. 9 ℃, respectively, with the percentage reductions being 10. 2%, 20. 8%, 13. 6%, and 11. 9% respectively. At the same time, the all-day average electrical power of the ventilation cavity with evaporative cooling is improved by approximately 15. 9% compared to the ventilation cavity without evaporative cooling. These experimental data verify the effectiveness of evaporative cooling technology in reducing the operating temperature of photovoltaic modules and improving the power generation efficiency of photovoltaic modules, and provide data support for the further application of photovoltaic building integration. [ABSTRACT FROM AUTHOR]

Simple Summary: The performance of search dogs is limited by their ability to cool down their body because the main cooling ability—panting—contradicts sniffing. We investigated the effect of hot environments on the general body condition of detection dogs working in Kenya. These dogs search for cheetah scats in their arid and hot habitat, where it is especially challenging for them to work. After a working day in the fields, these dogs showed a softer stool, which means a higher stress level, and elevated body temperature during the routine check-in the next morning. Our results showed that the use of search dogs in hot conditions is possible and useful but requires increased attention to prevent heat-related illness. Body temperature is an important physiological parameter that influences the performance of working dogs. The main cooling mechanism in dogs is panting to support evaporative cooling, which reduces the dog's ability to detect scents. In this study, we investigated the general body condition of four detection dogs searching for cheetah scats in a hot environment in northern Kenya. We evaluated the effect on the dog's body temperature post-work in the short term (within hours) and long term (12–24 h). The fecal consistency and mean body temperature of the investigated dogs differed significantly between individuals but not between locations (moderate Nairobi and hot Samburu). On the morning after fieldwork, the dogs showed a significantly increased body temperature (37.9 ± 0.8 °C) compared to resting days (37.5 ± 2.2 °C). In the short term, on the first day of fieldwork, the dog's body temperature (n = 2) decreased after 10 min of rest. On the second consecutive day of fieldwork, the 10-min recovery period was too short, and the body temperature did not decrease significantly. Our data showed that the use of detection dogs in hot conditions is possible and useful but requires increased attention to prevent heat-related illness. [ABSTRACT FROM AUTHOR]

Clinical trials of hypothermia after pediatric cardiac arrest (CA) have not seen robust improvement in functional outcome, possibly because of the long delay in achieving target temperature. Previous work in infant piglets showed that high nasal airflow, which induces evaporative cooling in the nasal mucosa, reduced regional brain temperature uniformly in half the time needed to reduce body temperature. Here, we evaluated whether initiation of hypothermia with high transnasal airflow provides neuroprotection without adverse effects in the setting of asphyxic CA. Anesthetized piglets underwent sham-operated procedures (n = 7) or asphyxic CA with normothermic recovery (38.5°C; n = 9) or hypothermia initiated by surface cooling at 10 (n = 8) or 120 (n = 7) min or transnasal cooling initiated at 10 (n = 7) or 120 (n = 7) min after resuscitation. Hypothermia was sustained at 34°C with surface cooling until 20 h followed by 6 h of rewarming. At 4 days of recovery, significant neuronal loss occurred in putamen and sensorimotor cortex. Transnasal cooling initiated at 10 min significantly rescued the number of viable neurons in putamen, whereas levels in putamen in other hypothermic groups remained less than sham levels. In sensorimotor cortex, neuronal viability in the four hypothermic groups was not significantly different from the sham group. These results demonstrate that early initiation of high transnasal airflow in a pediatric CA model is effective in protecting vulnerable brain regions. Because of its simplicity, portability, and low cost, transnasal cooling potentially could be deployed in the field or emergency room for early initiation of brain cooling after pediatric CA. NEW & NOTEWORTHY: The onset of therapeutic hypothermia after cardiac resuscitation is often delayed, leading to incomplete neuroprotection. In an infant swine model of asphyxic cardiac arrest, initiation of high transnasal airflow to maximize nasal evaporative cooling produced hypothermia sufficient to provide neuroprotection that was not inferior to body surface cooling. Because of its simplicity and portability, this technique may be of use in the field or emergency room for rapid brain cooling in pediatric cardiac arrest victims. [ABSTRACT FROM AUTHOR]

The global increase in temperature and the resulting climate change present a significant challenge for animal husbandry. Cattle are particularly affected by heat stress during the summer months. The objective of the study was to quantify the duration of heat stress hours during the summer months on ten farms with new or renovated cattle barns. Furthermore, the heat radiation of different ridge designs was evaluated in comparison to the respective roof construction. All farms experienced heat stress during the summer months, with those two farms utilising digital barn climate regulation exhibiting notable benefits. This suggests that digital barn climate regulation can play a pivotal role in mitigating heat stress in animals. Additionally, the findings validated the efficacy of green roofs in actively cooling through evaporative cooling. The heat input was considerably higher with uninsulated trapezoidal sheet metal roofs and light ridges than with sandwich roofs and membrane ridges. [ABSTRACT FROM AUTHOR]

Purpose: To determine the effect of taurine supplementation on sweating and core temperature responses, including the transition from compensable to uncompensable heat stress, during prolonged low-intensity exercise of a fixed-heat production (~ 200W/m2) in hot conditions (37.5 °C), at both fixed and incremental vapour-pressure. Methods: Fifteen females (n = 3) and males (n = 12; 27 ± 5 years, 78 ± 9 kg, V ˙ O2max 50.3 ± 7.8 mL/kg/min), completed a treadmill walking protocol (~ 200W/m2 heat production [Ḣprod]) in the heat (37.5 ± 0.1 °C) at fixed-(16-mmHg) and ramped-humidity (∆1.5-mmHg/5-min) following 1 week of oral taurine supplementation (50 mg/kg/bm) or placebo, in a double-blind, randomised, cross-over design. Participants were assessed for whole-body sweat loss (WBSL), local sweat rate (LSR), sweat gland activation (SGA), core temperature (Tcore), breakpoint of compensability (Pcrit) and calorimetric heat transfer components. Plasma volume and plasma taurine concentrations were established through pre- and post-trial blood samples. Results: Taurine supplementation increased WBSL by 26.6% and 5.1% (p = 0.035), LSR by 15.5% and 7.8% (p = 0.013), SGA (1 × 1 cm) by 32.2% and 29.9% (p < 0.001) and SGA (3 × 3 cm) by 22.1% and 17.1% (p = 0.015) during the fixed- and ramped-humidity exercise periods, respectively. Evaporative heat loss was enhanced by 27% (p = 0.010), heat-storage reduced by 72% (p = 0.024) and Pcrit was greater in taurine vs placebo (25.0-mmHg vs 21.7-mmHg; p = 0.002). Conclusion: Taurine supplementation increased sweating responses during fixed Ḣprod in hot conditions, prior to substantial heat strain and before the breakpoint of compensability, demonstrating improved thermoregulatory capacity. The enhanced evaporative cooling and reduced heat-storage delayed the subsequent upward inflection in Tcore—represented by a greater Pcrit—and offers a potential dietary supplementation strategy to support thermoregulation. [ABSTRACT FROM AUTHOR]

Traditional air conditioning systems use lot of energy; thus, dew point evaporative air-cooling systems could be a good alternative. Many experts studied the impact of constructional and operating characteristics on Maisotsenko cycle (M-cycle) to improve its performance. Cooler performance is influenced by the heat exchanger. Heat exchangers were constructed using flat and corrugated plates. The present study proposes the use of geometrically modified trapezoidal corrugated plates for counter flow heat exchanger, which consists of alternate air and water flow passageways. The numerical model is developed to predict the performance under variety of inlet air conditions and channel dimensions. In the standard range of incoming air properties such as relative humidity, the performance parameters assist in making cooler recommendations. Comparison and validation of simulation results are done with published experimental data for corrugated and trapezoidal corrugated plate heat exchangers. For trapezoidal corrugated plates, simulation findings revealed 10% increase in wet bulb efficiency and 7% increase in dew point efficiency over corrugated plates. The efficiency of wet bulb and dew point decreases as channel gap widens. For trapezoidal corrugated plates, the larger channel spacing minimises pressure drop. [ABSTRACT FROM AUTHOR]

Two new cold plates manufactured via metal 3D printing were experimentally investigated for thermal performance analysis in indirect liquid cooling operations; then they were compared to the traditional cold plates. Experiments were performed with different coolant inlet temperatures (15.7 °C and 24.5 °C) and ambient air velocities (0.5 m/s and 3 m/s) at tropical conditions; hereby, the impact of high dew point temperatures at tropics was also investigated. Body-centered cubic (BCC) and pillar elements were applied in the cooling cavity of the cold plates. The results showed that the target surface temperature in both BCC- and pillar-filled plate designs was maintained below the limits at the lower inlet temperature. However, at the higher inlet temperature, the temperature was only maintained below the limit when the ambient air velocity was 3 m/s. The convective heat transfer coefficient at the inlet temperature of 15.7 °C was found 1.5 and 2.5 times higher than the convective heat transfer coefficient value at the inlet temperature of 24.5 °C for the pillar- and BCC-filled plates, respectively. The performance evaluation criterion values were found in the range of 1.2 − 2.4, which depended on the operating conditions and were already higher than the referenced studies in the literature. [ABSTRACT FROM AUTHOR]

Large-scale reforestation, afforestation, and forest restoration schemes have gained global support as climate change mitigation strategies due to their significant carbon dioxide removal (CDR) potential. However, there has been limited research into the unintended consequences of forestation from a biophysical perspective. In the Community Earth System Model version 2 (CESM2), we apply a global forestation scenario, within a Paris Agreement-compatible warming scenario, to investigate the land surface and hydroclimate response. Compared to a control scenario where land use is fixed to present-day levels, the forestation scenario is up to 2 °C cooler at low latitudes by 2100, driven by a 10 % increase in evaporative cooling in forested areas. However, afforested areas where grassland or shrubland are replaced lead to a doubling of plant water demand in some tropical regions, causing significant decreases in soil moisture (∼ 5 % globally, 5 %–10 % regionally) and water availability (∼ 10 % globally, 10 %–15 % regionally) in regions with increased forest cover. While there are some increases in low cloud and seasonal precipitation over the expanded tropical forests, with enhanced negative cloud radiative forcing, the impacts on large-scale precipitation and atmospheric circulation are limited. This contrasts with the precipitation response to simulated large-scale deforestation found in previous studies. The forestation scenario demonstrates local cooling benefits without major disruption to global hydrodynamics beyond those already projected to result from climate change, in addition to the cooling associated with CDR. However, the water demands of extensive forestation, especially afforestation, have implications for its viability, given the uncertainty in future precipitation changes. [ABSTRACT FROM AUTHOR]

In this study, tubes filled with PCM as a thermal energy storage unit with an indirect air heater are used to store and recover solar thermal energy. Two different configurations of PCM-filled tubes (inline and staggered) in the unit are considered and compared with the PCM-filled plate unit. In all cases, the amount of the PCM is the same. The effects of airflow rate, diameter of tubes and inlet temperature on the charging and discharging rates are studied. Results showed that the PCM tube unit is more efficient than the PCM plate unit. The thermal performance is enhanced with the increase of the air mass flow rate. Results also revealed that the phase change rate in staggered configurations is between 7% and 36% (depending on the airflow rate) greater than that in the inline ones. By reducing the tube diameter, the melting and solidification processes are performed more quickly due to the rise of the overall heat transfer surface area. The influence of the temperature difference between the inlet air and PCM is more effective than the other considered effects where the 10 °C increase of the temperature difference enhances the charging rate by a factor of 2. [ABSTRACT FROM AUTHOR]

The purpose of this research is to investigate in depth the effect of system geometry on the performance of coil-and-tube heat exchangers. This work investigates the use of direct evaporative cooling (DEC) to improve the efficiency of air conditioning systems in extremely hot weather. DEC systems must be sized and constructed properly for the particular building and climate in which they are going to be installed. The ultimate goal is to reduce energy usage while producing affordable, green cooling options for regions with exceptionally hot temperatures. For simulation, we used computational fluid dynamics with ANSYS software. We purposefully varied the quantity of nozzles and the number of turns in the cooling tubes to see how they affected the effectiveness of the system. The temperature and velocity plot findings revealed a substantial difference, demonstrating that these engineering elements had an impact on the heat exchange process. According to the results, setups with 35 nozzles and 13 nozzle turns had a maximum coefficient of performance of 4.537 at an entry velocity of 2 m/s, showing that this configuration is ideal in the investigated conditions. The findings emphasize the need for strategically modifying some engineering parameters to increase heat exchanger performance and offer exciting prospects for the design and optimization of such systems. More research is needed to better understand these complicated interactions, including the investigation of different fluids, channel diameters, pressure conditions, and performance in the transient state. [ABSTRACT FROM AUTHOR]

The floral microenvironment impacts gametophyte viability and plant–pollinator interactions. Plants employ mechanisms to modify floral temperature, including thermogenesis, absorption of solar radiation, and evaporative cooling. Whether floral thermoregulation impacts reproductive fitness, and how floral morphological variation mediates thermoregulatory capacity are poorly understood.We measured temperature of the floral microenvironment in the field and tested for thermogenesis in the lab in early spring flowering Hexastylis arifolia (Aristolochiaceae). We evaluated whether thermoregulatory capacity was associated with floral morphological variation. Finally, we experimentally determined the thermal optimum and tolerance of pollen to assess whether thermoregulation may ameliorate thermal stress to pollen.Pollen germination was optimal near 21 °C, with a 50% tolerance breadth of ~18 °C. In laboratory conditions, flowers exhibited thermogenesis of 1.5–4.8 °C for short intervals within a conserved timeframe (08:00–09:00 h). In the field, temperature inside the floral tube often deviated from ambient – floral interiors were up to 4 °C above ambient when it was cold, but some fell nearly 10 °C below ambient during peak heat. Flowers with smaller openings were cooler and more thermally stable than those with larger openings during peak heat. Thermoregulation maintained a floral microenvironment within the thermal tolerance breadth of pollen.Results suggest that H. arifolia flowers have a stronger capacity to cool than to warm, and that narrower floral openings create a distinct floral microenvironment, enhancing floral cooling effects. While deviation of floral temperature from ambient conditions maintains a suitable environment for pollen and suggests an adaptive role of thermoregulation, we discuss adaptive and nonadaptive mechanisms underlying floral warming and cooling. [ABSTRACT FROM AUTHOR]

Over the last few decades North American flying squirrels (Glaucomys spp.) have experienced dramatic northward range shifts. Previous studies have focused on the potential effects of warming winter temperatures, yet the hypothesis that rising summer temperature had a role in these range shifts remained unexplored. We therefore sought to determine the effect of high environmental temperatures on the thermoregulation and energetics of flying squirrels in an area of the Northeast of North America with a recent species turnover. Unable to find a logistically feasible population of the northern species (Glaucomys sabrinus), we focused on Southern Flying Squirrels (G. volans). Using flow-through respirometry, we measured the relationship between metabolic rate, evaporative water loss, and body temperature at high ambient temperatures. We also measured core body temperature in free-ranging flying squirrels using temperature-sensitive data loggers. We detected no significant increase in metabolic rate up to ambient temperatures as high as 40 °C. However, evaporative water loss increased at temperatures above 36.2 °C. Free-ranging body temperature of flying squirrels followed a circadian pattern with a ~2 °C difference between active and resting phase modal body temperatures. Rest-phase body temperatures were influenced by environmental temperatures with higher resting temperatures observed on days with higher daily maximum ambient temperatures but not to an extent that energy or water costs were significantly increased during rest. We found that, due to a relatively high level of thermal tolerance, high ambient temperatures are unlikely to cause an energetic strain on Southern Flying Squirrels. However, these findings do not preclude negative impacts of high ambient temperatures on the northern species, and these may still play a role in the changing distributions of Glaucomys in North America. [ABSTRACT FROM AUTHOR]

Addressing heat stress in dairy farming is a substantial challenge, and there is an increasing need for efficient cooling systems, even in regions with moderate climates. Accurately predicting the efficacy of diverse cooling options under different climatic conditions is crucial for reducing heat stress in modern high-producing dairy cows, aligning with sustainability goals. This study assessed the effectiveness and feasibility of different cooling measures, including fans, sprinklers with fans, and evaporative air cooling, using a dynamic thermoregulatory model. This 3-node dynamic model was developed based on recent animal data simulating the processes of dairy cows' physiological regulation and heat dissipation under various environmental conditions. The cooling methods were based on two principles: enhancing heat loss from cows using fans with/without sprinklers; lowering the ambient temperature by evaporative air cooling. The predicted results were discussed and partly validated using the experimental data from the literature. The predictions indicated that fan cooling alone was effective in ambient temperatures below 26 °C, while higher temperatures required a combination of fans and sprinklers for effective heat stress alleviation. Consideration of individual cow characteristics and environmental factors, including fan speed and wetting area, is crucial for optimal cooling. In regions with high relative humidity, evaporative air cooling could be counterproductive to some extent. The model's predictions largely aligned with experimental data, demonstrating its capability to forecast cooling effects under various climatic conditions. Future model improvements included refining calculations for water holding capacity, wetted skin area, and dry time, depending on the influence of spraying time and rate. • Effectiveness of different cooling interventions on cows was predicted. • The selection of cooling measures should consider individual cows and environmental factors. • In humid regions, evaporative air cooling could be counterproductive. [ABSTRACT FROM AUTHOR]

Passive evaporative cooling technology using the building envelope is a crucial measure to mitigate the urban heat island effect. This study aims to enhance the cooling efficiency of the surface of enclosure structures by utilizing volcanic ash, potassium–sodium stone powder, and silica-based mesoporous oxide (SMO) as primary materials. These components are incorporated into the ceramic brick production process to create innovative humidity-controlling ceramic bricks (HCCTs). This study extensively investigates the impact of SMO and the amount of applied glaze on the physical and mechanical characteristics of these HCCTs. Additionally, it examines the water absorption and evaporative cooling properties of the studied materials under optimal substitution conditions. Numerical calculations are used to determine the heat and moisture transfer properties of HCCTs. The results indicate that incorporating 2% SMO and applying 70 g/m2 of glaze results in a moisture absorption capacity of 385 g/m2 and a moisture discharge capacity of 370 g/m2. These conditions also yield a notable flexural strength of 15.2 MPa. Importantly, the HCCTs exhibit significantly enhanced capillary water absorption and water retention capabilities. Increased water absorption reduces surface temperature by 2–3 °C, maintaining the evaporative cooling effect for 20 to 30 h. It is also found that the temperature of HCCTs decreases linearly with increasing water content and porosity, while the temperature difference gradually decreases with thickness. Water migration in HCCTs with greater thickness is notably influenced by gravity, with water moving from top to bottom. Therefore, it is recommended that brick thickness does not exceed 15 mm. [ABSTRACT FROM AUTHOR]

This study explores the features of leading modes of Subtropical Indian Ocean (SIO) sea surface temperature (SST) variability and their representation in CMIP6 models. The first EOF mode of SIO SST, featured by an SST anomaly elongated from the northwestern to the southeastern SIO region is triggered by the El Niño/Southern Oscillation (ENSO). ENSO-induced wind anomalies over the SIO region weaken the climatological southeasterlies, reduce evaporative cooling, and consequently warm the SST in subtropics. The first SIO mode is closely related to the Indian Ocean Basin Mode. The CMIP6 models' skill in simulating this mode is attributable to their accurate representation of ENSO impacts in this region. At the same time, the skill of simulation of the second mode, the Subtropical Indian Ocean Dipole (SIOD), is poor in most models due to the misrepresentation of the pure tropical Indian Ocean Dipole (IOD) events. As pure IOD events generate SIOD, underestimation of the occurrence of pure IOD events will affect the development of SIOD in models. The CMIP6 model experiments reveal the absence of ENSO forcing on SIOD. Notably, regardless of the bias in co-occurred and pure IOD events, most of the models overestimate IOD strength due to the easterly surface wind bias and the associated thermocline depth bias. The easterly bias in the equatorial Indian Ocean surface wind weakens the Wyrtki jet, creating a shallow (deep) thermocline bias in the eastern (western) TIO. This induces an overestimation of warm (cold) SST in the western (eastern) TIO during positive IODs. [ABSTRACT FROM AUTHOR]

Atmospheric convection across the northern inter-Americas is modulated by trade-wind subsidence and subtropical easterly waves from June to October. Northward migration of the equatorial trough is coupled to the meridional circulation (MC) and surface temperatures above 27ºC. Forming a MC index via S-N height sections of total and anomalous streamfunction, statistical relationships are examined which focus on Jun-Oct season when the South American monsoon is quiescent. Both east Pacific and tropical north Atlantic exhibit cool ocean – dry atmosphere response to an intensified MC. During periods of faster MC, composite humidity is depleted over the Caribbean 10–25 N in conjunction with westerly wind shear, thereby limiting atmospheric convection. The ocean response to intensified MC is evaporative cooling and a deep layer of increased salinity in the Caribbean, that may sustain anomalous air-sea interactions. Long-term trends reveal intensification of the MC in boreal summer: rising over the Amazon, subsiding over the Caribbean, inter-connected by lower and upper airflows. The annually pulsed MC conspires with inter-decadal trends to produce many of the features presented. [ABSTRACT FROM AUTHOR]

Heatwaves and soil droughts are increasing in frequency and intensity, leading many tree species to exceed their thermal thresholds, and driving wide‐scale forest mortality. Therefore, investigating heat tolerance and canopy temperature regulation mechanisms is essential to understanding and predicting tree vulnerability to hot droughts. We measured the diurnal and seasonal variation in leaf water potential (Ψ), gas exchange (photosynthesis Anet and stomatal conductance gs), canopy temperature (Tcan), and heat tolerance (leaf critical temperature Tcrit and thermal safety margins TSM, i.e., the difference between maximum Tcan and Tcrit) in three oak species in forests along a latitudinal gradient (Quercus petraea in Switzerland, Quercus ilex in France, and Quercus coccifera in Spain) throughout the growing season. Gas exchange and Ψ of all species were strongly reduced by increased air temperature (Tair) and soil drying, resulting in stomatal closure and inhibition of photosynthesis in Q. ilex and Q. coccifera when Tair surpassed 30°C and soil moisture dropped below 14%. Across all seasons, Tcan was mainly above Tair but increased strongly (up to 10°C > Tair) when Anet was null or negative. Although trees endured extreme Tair (up to 42°C), positive TSM were maintained during the growing season due to high Tcrit in all species (average Tcrit of 54.7°C) and possibly stomatal decoupling (i.e., Anet ≤0 while gs >0). Indeed, Q. ilex and Q. coccifera trees maintained low but positive gs (despite null Anet), decreasing Ψ passed embolism thresholds. This may have prevented Tcan from rising above Tcrit during extreme heat. Overall, our work highlighted that the mechanisms behind heat tolerance and leaf temperature regulation in oak trees include a combination of high evaporative cooling, large heat tolerance limits, and stomatal decoupling. These processes must be considered to accurately predict plant damages, survival, and mortality during extreme heatwaves. [ABSTRACT FROM AUTHOR]