Search Results (120)

Rapid growth in artificial intelligence, machine learning, and high-performance computing has substantially increased data centre rack power densities, resulting in higher heat generation and more demanding cooling requirements. As water remains widely used in many cooling systems, understanding the relationship between cooling technologies and water consumption is essential for improving cooling efficiency and sustainability. This paper presents a survey of reported water usage effectiveness (WUE) across 83 data centre entries, providing a combined dataset that links WUE with heat-rejection categories. The reported data shows that 23 of these data centres exceed 0.4 L/kWh, which is a sustainability target specified by the Climate Neutral Data Centre Pact for new data centres in water-stressed regions using potable water. Dry facilities employing closed-loop liquid cooling require essentially no water, while evaporative systems typically report water usage effectiveness values up to 2.5 L/kWh. Reported WUE is a facility-level operational metric, set by the proportion of the IT heat load rejected by evaporation, which depends on the heat-rejection topology, ambient wet-bulb conditions, and operating set points. A higher server-side heat transfer coefficient permits a higher coolant supply temperature for a given chip temperature limit, widening the range of ambient conditions under which heat can be rejected without evaporative assistance. Server-side heat transfer is therefore an enabling condition for low WUE rather than a determinant of it. One-dimensional heat transfer models are developed to estimate heat transfer coefficients for different server-level cooling mechanisms widely used for cooling servers within data centres, including air cooling, single-phase immersion cooling, direct liquid cooling, and two-phase immersion cooling. Air cooling, with the lowest heat transfer coefficient, remains widely used in small-scale facilities, whereas direct liquid cooling and two-phase immersion cooling achieve coefficients up to three orders of magnitude higher and are increasingly deployed in high-density installations. These coefficients are used to derive an equivalent evaporative water demand, an upper-bound estimate of the water that would be evaporated in rejecting the heat each mechanism removes; it shares the units of reported WUE but describes thermal capability rather than facility water consumption. Full article

Freeze desalination (FD) is being reconsidered as a low-temperature desalination route because it separates water through ice formation rather than evaporation or membrane pressure. This review examines FD from the perspective of sustainable water–energy systems, with emphasis on applications where conventional desalination may face technical or energy limitations. Unlike general reviews focused mainly on freezing principles, this work connects crystallization mechanisms, experimental performance, energy integration, and scale-up barriers. The literature analyzed, consisting primarily of studies published between 2015 and 2026, was grouped into four areas: modeling and simulation, experimental and pilot-scale validation, technological integration, and energy–economic assessment. Recent progress has been reported in eutectic freeze crystallization, vacuum-assisted ice–brine separation, ice morphology control, LNG cold recovery, solar-assisted FD, and hybrid systems that combine desalination with cooling or energy recovery. Reported performance varies widely. Reported SEC varies by more than an order of magnitude: values near 3 kWh/m³ occur mainly under favorable integration or external-cold assumptions, whereas conventionally refrigerated laboratory and pilot systems can require substantially more energy. This difference shows that FD performance depends strongly on crystallizer design, feedwater composition, separation strategy, and cold-energy recovery. FD should not be viewed as a direct replacement for RO, MED, or MSF. Its strongest potential is in hypersaline brine treatment, LNG terminals, cold regions, off-grid systems, island communities, and decentralized water production coupled with renewable or waste-cold sources. Full article

This paper presents the design and experimental investigation of an indirect regenerative evaporative cooling (IREC) system based on the M-cycle concept for electronic systems operating in high ambient temperature. The proposed heat exchanger consists of dry and wet vertical channels separated by thin copper walls and equipped with an open-water reservoir located at the bottom of the cooler. Airflow is introduced into the dry channels, where it is pre-cooled and directed toward a heat source. Next, it is redirected into the wet channels in a counter-flow arrangement. The heat source consists of power MOSFET transistors operating in current-source mode, with enhanced convective heat transfer achieved through attached heat sinks. Temperature and relative humidity sensors were installed at key measurement points to monitor thermodynamic conditions in the exchanger. The findings demonstrate the potential of the IREC approach as an effective and energy-efficient solution for cooling electronic systems in elevated temperature environments. Full article

This study investigates numerically a Coupled Solar Ventilation Evaporative Cooling system for hot and arid climates. The system uses a solar wall chimney to produce natural ventilation and generate hot and dry airflow, which is then directed through a roof-mounted humid hay packed bed to enhance evaporative air conditioning. The resulting cold is transferred via a thermally conductive inner roof plate while a membrane condenser recovers moisture for reusing. A mathematical model was developed to describe heat and mass transfer in the hay packed bed, including solar chimney airflow, pressure drop and the evaporation energy balance. Parametric simulations were carried out for inlet air temperature of 40–60 °C, airflow rates of 0.25–0.45 m³/s, hay moisture contents of 0.006–0.014 kg/kg dry basis and air humidity ratio of 0.002–0.006 kg/kg dry air. Results show that evaporative cooling becomes effective only above certain inlet temperature. Increasing airflow from 0.25 to 0.45 m³/s reduced hay temperature from 30 to 26.8 °C when inlet air temperature exceeded 43.5 °C. Higher hay moisture content enhanced cooling performance, reaching about 26 °C, while higher inlet air humidity reduced evaporation and limited cooling. The operating maps obtained from the numerical simulations provide practical guidance for preliminary system sizing and for optimal operating parameters selection in solar-driven evaporative cooling systems. The mathematical model treats the solar chimney, the evaporative packed bed, the conditioned room and the membrane condenser within the same steady state calculation. The solar energy balance and the pressure balance are used to relate the inlet air temperature and the airflow rate to solar irradiance, ambient temperature and chimney geometry. The model also includes the heat transferred from the room through the roof plate, the sensible heat of the supplied water and the mass transfer and pressure drop effects of the membrane condenser. Full article

The climate crisis, housing precarity, and the loss of everyday architectural heritage are converging challenges in Mediterranean cities. This article investigates the adaptive reuse of early twentieth-century adobe refugee dwellings in Nea Ionia and Kaisariani, neighborhoods of Attica, Greece, as an integrated social, environmental, and cultural strategy. Historical documentation, urban-morphological analysis, field observations, building survey data, material assessment, and design-based microclimatic analysis were combined to evaluate compatible restoration and bioclimatic upgrades as alternatives to demolition and conventional energy retrofit practices, with the main aim of preserving an important part of Greek history and architecture. The study develops a replicable qualitative assessment framework that identifies how existing adobe envelopes, compact layouts, courtyards, thresholds, vegetated pergolas, and low-water evaporative cooling may support low-carbon housing reuse. The results clarify the current preservation conditions and reuse potential of the selected case-study fragments, showing that adobe dwellings can preserve embodied material value, retain thermal mass and hygroscopic regulation, and support social housing when repaired with compatible, low-impact techniques. The article argues that the reuse of adobe refugee dwellings can function as a distributed urban strategy for housing provision, heritage continuity, and microclimatic adaptation. Its main contribution is a transferable analytical framework for assessing overlooked earthen housing stocks in dense Mediterranean contexts. The study argues that adaptive reuse can serve simultaneously as a means of social housing, a mechanism for optimizing the microclimate, and a means of preserving the tangible and intangible heritage of Greek adobe buildings that have been standing for over 100 years. This position extends circular construction debates by prioritizing non-demolition and direct reuse while preserving an important period of history. Full article

The ocean–atmosphere turbulent heat exchange plays a critical role in the energy and moisture budgets of the Tropical Atlantic Ocean (TAO) and in weather and climate forecasts. However, its estimation strongly depends on the choice of bulk parameterization, as direct in situ measurements are sparse. This study evaluates sensible (Hs) and latent (Hl) heat fluxes derived from three bulk parameterization schemes used operationally in models at the Brazilian Center for Weather Forecast and Climate Studies (CPTEC) of the National Institute for Space Research (INPE), Brazil: the Brazilian Atmospheric Model (BAM), the Modular Ocean Model version 6 (MOM6), and the Weather Research and Forecasting (WRF) model. Using daily in situ observations from seven Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) buoys across the TAO during 1997–2023, we computed monthly mean fluxes and compared them against the Coupled Ocean–atmosphere Response Experiment (COARE) algorithm version 3.0b (COARE 3.0b) reference. COARE version 3.6 (COARE 3.6) and European Centre for Medium-Range Weather Forecast (ECMWF) Reanalysis 5th generation (ERA5) data were included as additional benchmarks. All offline schemes were forced with identical buoy data, isolating differences in internal physical assumptions. Hl is approximately one order of magnitude larger than Hs across all sites, and inter-scheme differences are substantially larger for Hl (±50 W∙m⁻²) than for Hs (±5 W∙m⁻²). All schemes reproduce the seasonal cycle linked to the Intertropical Convergence Zone (ITCZ) migration and trade-wind variability, with correlations generally exceeding 0.8 (p < 0.001) for most buoys. However, systematic magnitude biases remain. The Coordinated Ocean Research Experiments (CORE) bulk formulation implemented in MOM6 (MOM6-CORE) shows high temporal correlation (often r ≈ 1.0) but a persistent negative bias for both Hs and Hl (e.g., B1 Hl bias = −24.0 W∙m⁻²), indicating weaker turbulent exchange relative to COARE 3.0b. BAM overestimates Hs (by 1–3 W∙m⁻²) and underestimates Hl at most northern and southern sites, while the parametrization of the Yonsei University (YSU) implemented in the WRF model (WRF-YSU) amplifies Hs variability intermittently, particularly at the equator (B4). As expected, COARE 3.6 remains the closest to the reference (differences < 1 W∙m⁻² for Hs and <7 W∙m⁻² for Hl; r ≈ 0.99). ERA5 captures temporal variability well (r ≈ 0.7–0.9) but systematically overestimates Hl (positive bias up to +47.6 W∙m⁻² at B7), implying stronger evaporative cooling. Buoy-specific regimes modulate skill. The choice of bulk formulation thus remains a first-order source of uncertainty in turbulent heat flux estimates over the TAO, with direct implications for mixed-layer heat budgets, SST evolution, and coupled ocean–atmosphere variability. MOM6-CORE provides the most consistent performance relative to the COARE reference and emerges as the most robust option for operational applications at CPTEC/INPE. The findings also provide guidance for improving the representation of ocean–atmosphere turbulent exchanges in MONAN (Model for Ocean-Land-Atmosphere Prediction), the new Brazilian Earth System Model under development for weather and climate prediction. Full article

Post-harvest losses of fruits and vegetables are an important bottleneck in food systems of countries around the world, with 30–50% of perishable food items lost between farm and consumer, smallholder farmers in low-and-middle income countries (LMICs) with poor cold chain infrastructures facing a disproportionate burden. Evaporative cooling (EC) is a low-cost and energy-efficient alternative to mechanical refrigeration; however, traditional systems are operated in one position and are dependent on climate, which restricts its performance. The combination of Internet of Things (IoT) sensing, machine learning (ML), and the advanced control theory has made intelligent evaporative cooling systems (IECS) adaptive, data-driven platforms that can regulate the environment in real-time and optimise autonomously. This is a systematic literature review that was carried out according to PRISMA 2020, summarising 94 peer-reviewed articles published in 2018–2025 to map the technological landscape, performance indicators, and research directions of the field of post-harvest fruit and vegetable preservation using IECS. Findings indicate that IECS can considerably lower the storage temperatures, increase the shelf life by 50–200%, and reduce energy consumption by 75–90% compared to traditional refrigeration, and the payback period is as short as 1.2 years. In arid conditions, ML models are accurate in prediction with an R² of 0.98. The gaps in the research identified are a lack of validation in wet climatic conditions, non-existent standardised Ag-IoT protocols, inadequate Food–Energy–Water (FEW) nexus calculation, and no explainable AI (XAI) interfaces. An example of a conceptual framework of four layers synthesised is proposed to direct next-generation research and implementation of the IECS. Full article

With the escalating energy consumption of air conditioning systems worldwide, reducing such energy use has become a critical research priority. Evaporative cooling technology plays a significant role in reducing the energy consumption of existing air conditioning systems, especially by enhancing the heat exchange efficiency of condensers. This paper presents the design of an evaporative cooling household split-type air conditioner (SAC) that employs a submerged water method. By utilizing motor-driven rotation, the water distributor ensures full and even water distribution across a double-layer wet pad. Additionally, condensate water is recycled, and direct evaporative cooling (DEC) technology is applied to lower the condenser temperature, thereby achieving energy savings. Experiments were conducted under various meteorological conditions, comparing the performance of the split air conditioning system with the water distributor to that of the system without it. The comparative experiments revealed that the average air temperature differences at the inlet and outlet of the water distributor were 8.7 °C and 4.8 °C, respectively, with maximum air temperature differences reaching 12.3 °C and 8.2 °C, respectively. Compared to the system without the water distributor, the average condensing temperature at the condenser outlet of the system with the water distributor was reduced by 2.6 °C and 2.1 °C. Moreover, within an 11 h operation period, the average system coefficient of performance (COP) increased by 22.6% and 18.2%, respectively, and the energy savings reached 17.9% and 12.7%, respectively. Full article

Climate change is driven by global-scale warming, while cities additionally experience local amplification due to the urban heat island (UHI) effect (urban–rural temperature differences caused by urban form, materials, and reduced evapotranspiration). In this study, we address both dimensions by analyzing long-term near-surface climate variables and derived heat-exposure indicators for multiple South European cities and by translating climate signals into climate-suitability indicators for passive/evaporative cooling. In this study, heat-stress-relevant indicators and evaporative/adiabatic cooling opportunity across paired coastal and inland South European cities are quantified using long-term hourly reanalysis and scenario-based future projections. This paper compares coastal and inland city pairs from three regions: Nicosia and Limassol from Cyprus, Seville and Lisbon on the Iberian Peninsula, and Niš and Thessaloniki on the Balkans, to characterize recent heat stress and the prospective applications and limits of adiabatic cooling. ERA5/ERA5-Land variables from the Copernicus Climate Data Base, focusing on 2 m air temperature, 2 m dew point/relative humidity, and derived indicators: days above heat thresholds and “tropical nights”, were used to determine the differences between the local climate and compare severity of effects of global warming with respect to the specific climatic conditions of the chosen cities. Application of evaporative cooling was then tested with projections up to 2050 using Climate Consultant software, using regional temperature and humidity differences to explore comfort shifts and passive cooling applicability envelopes. Cross-city comparison of climate-suitability hours and cooling needs is included in the analysis. The novelty is a paired coastal–inland, multi-region South European design (Cyprus, Iberia, and Balkans) that combines long-term hourly reanalysis (1950–2025), scenario-based mid-century morphing, and a standardized psychrometric/adaptive-comfort framework to translate climate signals into comparable climate-suitability indicators for evaporative/adiabatic cooling across contrasting humidity regimes. The results provide planning direction by indicating that humid coastal cities should prioritize shading, reduced radiant load, ventilation/urban porosity and humidity-aware cooling, while hotter and drier inland cities retain a wider climatic window for evaporative cooling, subject to water-availability constraints. Full article

This study experimentally investigates a novel hybrid system integrating thermoelectric generators (TEGs) with direct contact membrane distillation (DCMD) for simultaneous low-grade heat recovery, electricity generation, and water desalination. Commercial TEG modules were sandwiched between heat spreaders to transfer thermal energy from a source (approx. 140 °C) to a cooling sink, driving saline water evaporation through a hydrophobic membrane. A validated mathematical model showed strong agreement with the experimental results. The system achieved freshwater mass fluxes of 8–9.5 kg/m²/h and electrical power outputs density of 25–35 W/m². Increasing heat input (450–700 W) significantly enhanced freshwater production and electrical output, improving the Gain Output Ratio (GOR) and reducing Specific Energy Consumption (SEC). While higher feed salinity (up to 35,000 ppm) measurably declined mass flux and thermal efficiency, thermoelectric generation and thermal resistance remained largely unaffected. Energy and exergy efficiencies showed moderate sensitivity to operating conditions, while the Water–Electrical Energy Cogeneration Index (WEeCI) increased at high salinity, highlighting the robust contribution of electricity generation. These results demonstrate the potential of the TEG–DCMD system for the sustainable co-generation of water and power from industrial waste heat or renewable thermal sources. Full article

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. Full article

The Arid Region of Northwest China (ARNC) functions as a critical ecological barrier for the Eurasian hinterland. To clarify the non-linear drivers of eco-environmental dynamics, a long-term (2000–2024) Remote Sensing Ecological Index (RSEI) time series was constructed and analyzed using an interpretable machine learning framework (XGBoost-SHAP). The analysis reveals pronounced spatial asymmetry in ecological evolution: improvements are concentrated in localized, human-managed areas, while degradation occurs as a diffuse process driven by geomorphological inertia. The ARNC exhibits low-level stability (mean RSEI 0.25–0.30) and marked unbalanced dynamics, with significant degradation (19.9%) affecting more than twice the area of improvement (6.5%). Attribution analysis identifies divergent driving mechanisms: ecological improvement (R² = 0.559) is primarily anthropogenic (58.3%), whereas degradation (R² = 0.692) is mainly governed by natural constraints (58.4%), particularly structural topographic factors, where intrinsic landscape vulnerability is exacerbated by human activities. SHAP analysis corroborates a “Greenness-Quality Paradox” in stable agroecosystems, where high vegetation cover coincides with reduced evaporative cooling and secondary salinization from irrigation, resulting in declining Eco-Environmental Quality (EEQ). A zero-threshold effect for grazing intensity is also identified, indicating that any increase beyond the baseline immediately initiates ecological decline. In response, a Resist-Accept-Direct (RAD) framework is proposed: direct salt-water balance regulation in oases, resist hydrological cutoff in ecotones, and accept natural dynamics in the desert matrix. These findings provide a scientific basis for reconciling artificial greening initiatives with hydrological sustainability in water-limited regions. Full article

Climate change and rising temperatures in cities due to the urban heat island (UHI) effect are causing increased heat stress and driving the development of efficient, sustainable outdoor cooling systems. The aim of this article was to analyze the integration of adiabatic air cooling systems with photovoltaic (PV) installations in the context of improving thermal comfort and energy autonomy. The study was conducted on the example of a bus station in Rzeszow (Poland), considering two system variants: indirect evaporative cooling and direct evaporative cooling. To assess the impact of comfort parameters on the number of hours of system operation, energy consumption, and operating costs, four upper thermal comfort limits were considered: 22 °C, 22.9 °C, 24 °C, and 25 °C. The results indicate that increasing the upper limit of thermal comfort reduces the operating time of the system and significantly reduces the demand for cooling—for example, increasing the thermal comfort range from 22.9 °C to 24 °C reduces useful energy by 41%. Assuming a thermal comfort range of 25 °C, the direct evaporative cooling system achieves full energy autonomy and is fully powered by photovoltaics. Life cycle analysis (LCA) and life cycle cost (LCC) confirmed the environmental and economic benefits of using higher thermal comfort values. The study highlights the potential of adiabatic cooling systems, in conjunction with a local photovoltaic installation, as an adaptive solution that improves thermal comfort in urban spaces with minimal energy consumption from the grid. Full article

In slab continuous casting, achieving uniform cooling in the secondary cooling zone is essential for ensuring both surface integrity and internal quality. To optimize the process for ship plate steel, a solidification heat transfer model was developed, incorporating radiation, water film evaporation, spray impingement, and roll contact. The influence of secondary cooling water flow on slab temperature distribution was systematically investigated from multiple perspectives. The results show that a weak cooling strategy is crucial for maintaining higher surface temperatures and aligning the solidification endpoint with the soft reduction zone. Along the casting direction, a “strong-to-weak” cooling pattern effectively prevents abrupt temperature fluctuations, while reducing the inner-to-outer arc water ratio from 1.0 to 0.74 mitigates transverse thermal gradients. In addition, shutting off selected nozzles in the later stage of secondary cooling at medium and low casting speeds increases the slab corner temperature in the straightening zone by approximately 50 °C, thereby avoiding brittle temperature ranges. Overall, the proposed multi-dimensional uniform cooling strategy reduces temperature fluctuations and significantly improves slab quality, demonstrating strong potential for industrial application. Full article

In Northeast Brazil, climatic factors and technology synergistically enhance melon productivity and fruit quality. However, the region requires further research on the efficient use of water resources, particularly in determining the crop coefficient (Kc), which comprises the evaporation coefficient (Ke) and the transpiration coefficient (Kcb). Air temperature affects crop growth and development, altering the spectral response and the Kcb. However, the direct influence of air temperature on Kcb and spectral response remains underemphasized. This study employed unmanned aerial vehicle (UAV) with RGB and Red-Green-NIR sensors imagery to extract biophysical parameters for improved water management in melon cultivation in semiarid northern Bahia. Field experiments were conducted during two distinct periods: warm (October–December 2019) and cool (June–August 2020). The ‘Gladial’ and ‘Cantaloupe’ cultivars exhibited higher Kcb values during the warm season (2.753–3.450 and 3.087–3.856, respectively) and lower during the cool season (0.815–0.993 and 1.118–1.317). NDVI-based estimates of Kcb showed strong correlations with field data (r > 0.80), confirming its predictive potential. The results demonstrate that UAV-derived NDVI enables reliable estimation of melon Kcb across seasons, supporting its application for evapotranspiration modeling and precision irrigation in the Brazilian semiarid context. Full article