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The purpose of this study is to compare the effects of two different ways of stopping incubator humidification on episodes of hypothermia, hyperthermia, hyponatraemia, hypernatraemia, or skin injury. The design is a single site, two-armed, parallel, randomised, clinical trial conducted between April 2019 and March 2022. The setting was a quaternary referral and teaching hospital in Queensland, Australia. There were 140 extremely preterm infants, born < 28 weeks gestational age (GA). Intervention groups were (1) cease humidity: incubator humidification turned from 80% to off at 00.01am on day 8 of life (n = 70); or (2) gradually reduce humidity: incubator humidification reduced by 5% at 00:01 of each day from day 8 until ceased on day 14 (n = 70). The primary outcome was episodes of temperature instability: defined as either hypothermia < 36.5 °C or hyperthermia > 37.5 °C. Secondary outcomes included episodes of hyponatraemia: hypernatraemia or skin injury. One hundred forty infants were enrolled, 70 in each group. No statistically significant differences for any outcomes. Hyperthermia: 77% (n = 54) in the cease group and 73% (n = 51) in the gradual reduction group (P = 0.70). Hypothermia: 53% (n = 37) in the cease group and 37% (n = 26) in the gradual reduction group (P = 0.09). The number of hyponatraemic events was similar for both groups (P = 0.73), as for hypernatraemic events (P = 0.3). Skin injury in week 2 of life: 63% in the cease group and 67% in the gradual reduction group (P = 0.72). Conclusions: Ceasing or gradually reducing incubator humidification after day 7 of life had no effect on the number of episodes of hypothermia or hyperthermia in this cohort of extremely preterm infants (EPTI). There was also no effect on the number of episodes of hyponatraemia or hypernatraemia. Trial registration: ANZCTR.org.au (Australia New Zealand Clinical Trials Registry). ACTRN 1261 9000 266167 Registered 21/2/2019. What is Known: • Incubator humidification is a widely accepted and routine practice in the management of EPTI as it influences transepidermal water loss (TEWL) and supports thermoregulation. However, weaning practices remain varied and inconsistent across the globe. • There remains a paucity of data to inform specific evidenced-based humidification practices. What is New: • Ceasing or gradually reducing incubator humidification after 7 days had no effect on temperature stability, serum sodium levels, or frequency of skin injury in this cohort of EPTI between day 8 and day 14. • There is no apparent benefit in prolonging incubator humidity beyond day 7 of life in these EPTI. [ABSTRACT FROM AUTHOR]

Climate change is a global problem that is accompanied by the significant changes in humidification conditions in many regions all over the world. The study examined spatiotemporal changes in humidification zones in southern Russia in the period 1961–2020. Humidification zones were determined in accordance with the classification of the Selyaninov hydrothermal coefficient. During the research period, a significant increase in average annual temperatures was noted for the region (+ 0.31 °C/decade) and generally positive, but insignificant, dynamics of annual precipitation (+ 4.80 mm/decade). These changes were accompanied by a significant shift in the humidification zones. Despite some periods of decline, the territories of semi-desert and desert zones, as well as dry steppes, have significantly expanded from the east of the region to the west in the last decade. The expansion of these zones was primarily due to a reduction in the area of the more humid steppe zone, with a lesser contribution from the forest-steppe zone. Overall, during the study period, the area of semi-desert and desert zone expanded by an average of + 5.505 thou km2/decade. The zone of the Taiga and deciduous forests has not undergone significant changes. The results obtained indicate arid warming and a general deterioration in humidification conditions in most of southern Russia in the period 1961–2020. According to calculations, further warming, other things being equal, can lead to an even greater expansion of the semi-desert and desert bioclimatic zone, which can provoke a number of socio-economic and environmental problems, especially in the eastern part of the region. [ABSTRACT FROM AUTHOR]

BACKGROUND: A model system described in International Organization for Standardization 9360 is the standard method for estimating the humidifying performance of heat and moisture exchangers (HMEs). However, there are no reliable bedside methods for evaluating the ongoing humidification performance of HMEs. Therefore, this study aimed to develop 2 clinically applicable methods for estimating the ongoing humidifying performance of HMEs and to evaluate their reliability in a model system. METHODS: Physiologically expired gas was simulated using a heated humidifier, and ventilation was delivered using a ventilator with constant flow through 3 different types of HMEs. Relative humidity (RH) was measured using a capacitive-type moisture sensor. Water content lost during expiration was calculated by integrating absolute humidity (AH), instantaneous gas flow measured at the expiratory outlet of the ventilator, and time. We also calculated the water content released and captured by the HMEs during tidal ventilation by integrating the difference in AH across the HMEs, instantaneous gas flow, and time. RESULTS: We found that the RH, temperature, and AH were almost constant on the expiratory outlet of the ventilator but rapidly varied near the HMEs. The water content lost by the 3 HMEs was associated with the manufacturer-reported values and inversely correlated with the calculated values of the water content exchanged by the HMEs. The water content released and captured by HMEs was closely correlated with the difference in HME weight measured at the end of inspiration and expiration; however, the water content captured by HMEs seemed to be overestimated. CONCLUSIONS: Our results demonstrated that our system was able to detect the differences in the performance of 3 models of HMEs and suggest that our method for calculating water loss is reliable for estimating the water retention performance of HMEs during mechanical ventilation, even in the presence of a constant flow. [ABSTRACT FROM AUTHOR]

Traditional automotive proton exchange membrane fuel cell (PEMFC) endurance testing relies on the fuel cell (FC) dynamic load cycle (FC‐DLC) protocol, which inadequately reflects real‐world driving conditions. To address this limitation the "Investigations on degradation mechanisms and Definition of protocols for PEM Fuel cells Accelerated Stress Testing" (ID‐FAST) consortium defined the new representative "ID‐FAST driving load cycle," a novel approach capturing the load distribution, transitions, temperature variations, and humidity fluctuations experienced by FCs in real‐world operation. We demonstrate the ID‐FAST driving cycle itself and the integration into a realistic durability test program for FC test benches and present the resulting test data. Furthermore, we showcase its implementation within an accelerated stress testing (AST) protocol, highlighting its potential to significantly reduce testing time by accelerating degradation. Additionally, a novel method for highly dynamic humidity adjustment within test benches is introduced. By overcoming limitations of existing methods and incorporating the ID‐FAST driving cycle, this work paves the way for a new era of efficient and realistic FC endurance testing, ultimately contributing to the development of more robust and durable automotive FC stacks. [ABSTRACT FROM AUTHOR]

The perfect combination of renewable energy and desalination technologies is the key to meeting water demands in a cost-effective, efficient and environmentally friendly way. The desalination technique by humidification-dehumidification is non-conventional approach suitable for areas with low infrastructure (such as rural and decentralized regions) since it does not require permanent maintenance. In this study, this technology is implemented by using solar energy as a source of thermal power. A seawater desalination unit is considered, which consists of a chamber with two evaporators (humidifiers), a wetted porous material made of a corrugated cellulose cardboard and a condenser (dehumidifier). The evaporation system is tested with dry bulb temperature and relative air humidity data. The results of numerical simulations indicate that higher inlet air velocities (from 0.75 to 3 m/s) lead to a decrease in the ΔT, ΔRH, and effectiveness. With the air remaining within the evaporator for 30 cm, the temperature differential increases to 5.7°C, accompanied by a 39% rise in relative humidity contrast. These changes result in a significant enhancement in humidification efficiency, achieving a remarkable efficiency level of 78%. However, a wettability value of 630 m2/m3 leads to a smaller reduction of these parameters. Increasing the pad thickness, particularly to 0.3 m, improves performance by boosting ΔT, ΔRH, and effectiveness, especially for pads with a wettability of 630 m2/m3, for which superior performances are predicted by the numerical tests. [ABSTRACT FROM AUTHOR]

Recent climate change has accelerated the global hydrological cycle, substantially affecting drought metrics such as drought duration and drought propagation; however, knowledge of drought patterns in these metrics remains limited. Here, we aimed to address the evolution and influencing factors of major drought metrics under past and future climate scenarios within the Yellow River Basin (YRB) based on Coupled Model Intercomparison Project Phase 6 (CMIP6). Accordingly, we investigated the changes in drought duration for meteorological drought and agricultural drought across the YRB and identified the variability in drought propagation time from meteorological drought to agricultural drought by using a standardized precipitation/soil moisture index and run theory. Meteorological and agricultural drought duration, and propagation time, increased from 1850 to 2014, decreased significantly from 2015 to 2100 with change trends of −0.0027, −0.0197, and −0.002 month/year, respectively. Drought duration had a negative sensitivity to humidification, and agricultural drought was more sensitive than meteorological drought. Propagation time exhibited a greater sensitivity to meteorological humidification than agricultural humidification. The results also suggest that precipitation, evapotranspiration, and soil moisture are the main drivers of drought metric changes, with air temperature and crop cover exhibiting a strong indirect effect on drought metrics in the YRB. Decreased propagation time from meteorological to agricultural drought and decreased duration provide evidence for the accelerated occurrence and increased impact of drought, highlighting the importance of a more comprehensive understanding of drought metric changes under rapid climate change. [ABSTRACT FROM AUTHOR]

Aerosolized lung surfactant therapy during nasal continuous positive airway pressure (CPAP) support avoids intubation but is highly complex, with reported poor nebulizer efficiency and low pulmonary deposition. The study objective was to evaluate particle size, operational compatibility, and drug delivery efficiency with various nasal CPAP interfaces and gas humidity levels of a synthetic dry powder (DP) surfactant aerosol delivered by a low-flow aerosol chamber (LFAC) inhaler combined with bubble nasal CPAP (bCPAP). A particle impactor characterized DP surfactant aerosol particle size. Lung pressures and volumes were measured in a preterm infant nasal airway and lung model using LFAC flow injection into the bCPAP system with different nasal prongs. The LFAC was combined with bCPAP and a non-heated passover humidifier. DP surfactant mass deposition within the nasal airway and lung was quantified for different interfaces. Finally, surfactant aerosol therapy was investigated using select interfaces and bCPAP gas humidification by active heating. Surfactant aerosol particle size was 3.68 µm. Lung pressures and volumes were within an acceptable range for lung protection with LFAC actuation and bCPAP. Aerosol delivery of DP surfactant resulted in variable nasal airway (0-20%) and lung (0-40%) deposition. DP lung surfactant aerosols agglomerated in the prongs and nasal airways with significant reductions in lung delivery during active humidification of bCPAP gas. Our findings show high-efficiency delivery of small, synthetic DP surfactant particles without increasing the potential risk for lung injury during concurrent aerosol delivery and bCPAP with passive humidification. Specialized prongs adapted to minimize extrapulmonary aerosol losses and nasal deposition showed the greatest lung deposition. The use of heated, humidified bCPAP gases compromised drug delivery and safety. Safety and efficacy of DP aerosol delivery in preterm infants supported with bCPAP requires more research.

This research is centered around the development and construction of a test apparatus for a counterflow evaporative cooler. The packing material utilized in the testing is coconut coir with wettability values of 300, 400 and 500 m2/m3. The experiments involve varying the air velocity. The study examined performance characteristics, including evaporation rates, cooler efficiency, coefficient of performance (COP) and energy consumption information, in relation to the standard Celdek 7090 packaging. The findings demonstrated that employing a coconut coir with optimal wettability resulted in a cooling efficiency and COP of 53.57% and 1.25, respectively. These values were slightly lower than those achieved with the usual Celdek 7090 packing. Coconut coir, as a biomass-derived material, possesses certain benefits that make it a suitable alternative for filling materials in evaporative cooling processes.

The need for desalination is expected to evolve, and interests in novel techniques to enhance thermal desalination are developing. Research studies on ultrasonic atomization for desalination application has been observed in the last few years. Hence, this study aims to examine humidification process enhancement using ultrasonic atomization and interaction of atomized droplets with hot air in the humidifier. In the Humidification and Dehumidification (HDH) desalination system examined, the humidifier is equipped with a single ultrasonic atomizer unit which operates continuously with preheated hot air entering the humidifier chamber. The system is investigated for different air flowrates (40 – 100 LPM) and hot air temperatures (40, 50, and 60 °C). The average relative humidity at the humidifier outlet was maximum reaching 94 % for the highest flowrate. The results indicate that increasing hot air temperatures have significant improvement in droplet evaporation which causes higher relative humidity at the outlet, and increasing hot air flowrates have significant impact on the faster response of the humidification process to reach equilibrium.

ObjectiveNurses are key in administering oxygen therapy and managing its potential adverse effects in medical settings. This study aimed to investigate the knowledge, attitudes, and practices (KAP) regarding low-flow oxygen therapy and humidification among nurses.MethodsThis cross-sectional study was conducted from January 2024 to March 2024 at Shanghai Xuhui Central Hospital. Demographic data and KAP scores were collected through questionnaires.ResultA total of 243 valid questionnaires were collected. Among them, 228 (93.8%) were female, and 93 (38.3%) had been working for more than 10 years. The mean scores for knowledge, attitudes, and practices were 11.11 ± 4.30 (Ranging 0–18), 29.14 ± 3.41 (Ranging 7–35), and 28.07 ± 4.73 (Ranging 7–35), respectively. Multivariate logistic regression confirmed that knowledge (OR = 1.302, 95% CI: [1.167–1.453], p

Introduction. The study was carried out to determine the possible causes of damage to the finishing plaster coverings on the facades of historical stone buildings, built in St. Petersburg before 1917, as a result of their humidification and subsequent frost destruction.Materials and methods. The mechanism of humidification of a homogeneous wall structure plastered on both sides due to the moisture transfer from the room to the environment through the wall thickness due to the difference in partial pressures of water vapour from inside and outside the room during the cold season is studied. The paper provides the graphs of the distribution of the actual and maximum partial pressures of water vapour over the thickness of the wall structure, depending on the type of plaster covering, for two calculated cases — for the conditions of the coldest month and the coldest five-day period in St. Petersburg.Results. It is revealed that for the conditions of the coldest month in St. Petersburg, the actual partial pressure of water vapour in the thickness of the wall structure under consideration does not exceed the maximum, which indicates the absence of conditions for moisture condensation in the thickness of the wall envelope. However, as the vapour permeability of the external plaster decreases, the curves of the distribution of the actual and maximum partial pressures converge at the interface of the stone base and the plaster covering. For the conditions of the coldest five-day period, the actual partial pressure of water vapour already at a distance of 135 mm from the inner surface exceeds the maximum partial pressure, which indicates a high risk of moisture condensation, and this risk is the higher the less vapour permeable the plaster covering is.Conclusions. It is proven that when the coldest outdoor temperatures are established, there is a high probability of condensation of water vapour in the thickness of the wall structure under consideration. The highest risk of freezing of the condensable moisture will be observed at the interface of stone base with the external plaster. Freezing of moisture in cracks and voids in the contact zone of the stone base and the plaster covering can lead to water trapping, the occurrence of significant internal stresses in the finishing layer and, as a result, to its gradual damage, up to the loss of individual fragments of plaster.

Humidification is concerned with the addition of water vapour to a gas and can be measured as either absolute or relative. Adequate humidification is a vital consideration in anaesthesia given that the anatomical source of natural gas humidification (the nasopharynx) is generally bypassed, which can lead to complications including hypothermia, thickening of respiratory secretions, mucus plugging and airway keratinization. Humidification may be passive or active. Equipment involved in passive humidification includes heat and moisture exchanger (HME) filters, soda lime and cold water baths, with these devices able to achieve varying efficiencies without extrinsic energy input. Active humidification devices (including hot water baths) are capable of delivering a higher relative humidity but are associated with higher cost and potential hazards. While not strictly classed as true humidification devices, nebulizers are considered in this article as they add water droplets into a gas flow using a Venturi system, spinning discs or ultrasound vibration technology. [ABSTRACT FROM AUTHOR]

In the previous decades, loess landslides with amount of 1992 occurred in Yili valley, Xinjiang autonomous region of China. These landslides have caused a series of engineering disasters. However, comprehensive report regarding the characteristics of these landslides has not been made, and the sliding mechanism is also not thoroughly clarified. In order to address these issues, extensive field surveys and laboratory tests have been conducted. These results conclude that the length/width, sliding thickness, altitude and the gradient of these loess landslides mostly locate in the range of 10–300 m, 0.5–20 m, 1000–2500 m and 10°–50° respectively. Additionally, these loess landslides in Yili belong to the snow-melt landslides, which primarily occurred in the snow-melt season from yearly mid-February to mid-May. For these snow-melt landslides, the sliding mechanism includes following parts: freeze-thawing action notably weakens the shear strength of superficial loess, resulting in the sliding of superficial loess layer. Moreover, freeze-thawing also promotes the inner-fissures growth in superficial loess, increasing its hydraulic conductivity and accelerating the infiltration of melted snow-water or rainfall into lower loess layer. As lower loess becomes saturated, its strength diminishes significantly, further inducing the deep sliding. Highlights: Loess landslide in Yili occurred at shallow location and surrounded by fissure. Loess landslides in Yili valley belong to snow-melt landslides. Freeze-thawing action induce the sliding of superficial loess layer. Freeze-thawing accelerates infiltration of melted snow-water or rainfalls. Humidification action induces the deep-sliding of snow-melt landslides. [ABSTRACT FROM AUTHOR]

The introduction of fresh air into the indoor space leads to a significant increase in cooling or heating loads. Solid desiccant heat pump fresh air unit which can handle the latent and sensible load of fresh air efficiently have been proposed recently. To improve the performance of the solid desiccant heat pump fresh air unit in the fresh air handling process, in this paper, the application of composite silica gel in a heat pump fresh air unit was investigated. The comparison between silica gel coating (SGC) and composite silica gel coating (CSGC) shows that the adsorption rate and water uptake capacity of CSGC are more than two times higher than those of SGC. An experimental setup for the solid desiccant heat pump fresh air unit was established. The performance of SGC and CSGC was tested in the setup successively. Results show that under summer conditions, compared with the solid desiccant heat pump fresh air unit using silica gel (SGFU), the average moisture removal and COP of the one using composite silica gel (CSGFU) increased by 15% and 30%, respectively. Under winter conditions, compared with SGFU, the average humidification and COP of CSGFU increased by 42% and 17%. With optimal operation conditions of 3 min switchover time and 40 r/s compressor frequency, the COP of CSGFU under summer conditions can reach 7.6. Results also show that the CSGFU and SGFU have higher COP and dehumidification rate under higher outdoor temperature and humidity ratio. [ABSTRACT FROM AUTHOR]

Introduction: During mechanical ventilation (MV), inspired gases require heat and humidification. However, such conditions may be associated with reduced aerosol delivery efficiency. The practice of turning off heated humidification before nebulization and the impact of nebulization on humidity in a dry ventilator circuit remain topics of debate. This study aimed to assess the effect of turning off heated humidification on inhaled dose and humidity with nebulizer use during adult MV. Methods: A bronchodilator (albuterol) and two antibiotics (Colistimethate sodium and Amikacin sulfate) were nebulized with a vibrating mesh nebulizer placed at the humidifier inlet and in the inspiratory limb at the Y-piece. Additionally, albuterol was nebulized using a jet nebulizer in both placements. Aerosol particle size distribution was determined through a cascade impactor. Absolute humidity (AH) and temperature of inspired gases were determined with anemometer/hygrometers before, during, and after nebulization, before, during, and up to 60 minutes after interrupting active humidification. Aerosol collected on a filter distal to the endotracheal tube and on impactor stages were eluted and assayed by spectrophotometry. Results: The inhaled dose was greater when both nebulizers were placed at the humidifier inlet than the inspiratory limb at the Y-piece. Irrespective of the nebulizer types and placements, the inhaled dose either decreased or showed no significant change after the humidifier was turned off. The aerosol particle size ranged from 1.1 to 2.7 μm. With interruption of active humidification, humidity of inspired gas quickly dropped below recommended levels, and nebulization in dry ventilator circuit produced an AH between 10 and 20 mgH2O/L, lower than the recommended minimum of 30 mgH2O/L. Conclusion: Interrupting active humidification during MV before nebulization did not improve aerosol delivery efficiency for bronchodilator or antibiotics, but did reduce humidity below recommended levels. [ABSTRACT FROM AUTHOR]

The latest research progress of water vapor separation membrane technology is summarized, first introduces the classification of water vapor separation membrane materials, and the characteristics and research progress of different membrane materials are described・ Besides, the three categories and working principles of water vapor separation membranes with different structures in gas dehumidification and humidification are described systematically, and discusses the application and research status of water vapor separation membrane in the field of gas dehumidification at home and abroad・ The future research and development direction of membrane separation technology in the field of gas dehumidification and humidification are prospected. [ABSTRACT FROM AUTHOR]

The condenser's rejected heat in a vapour compression refrigeration system when thrown into the surrounding air results in its thermal pollution and gets wasted, while it has the potential to be recovered. Another major targeted concern is freshwater scarcity which is faced by the population in many areas. Addressing these difficulties, a double-stage integrated humidification-dehumidification and air conditioning system that recovers the condenser's waste heat and is assembled in a novel duct architecture is proposed. The obtained results of the developed model are established using the experimental data. The analysis explores the outcomes of the integrated system and investigates the influences of saline water temperature, humidifier efficiency, ambient temperature, and relative humidity on the output and performance metrics. The system provides air conditioning of 31.410 kJ and desalination of 65.020 mL from a unit volume of air using 0.661 kW of power and mitigates the environmental impact of existing technology. The coefficient of energy performance, cooling performance, gained output ratio, and exergy efficiency at the specified working situations are 0.958, 1.320, 6.809, and 2.701 %, respectively. A litre of freshwater costs $ 0.0068486. [ABSTRACT FROM AUTHOR]

Solar energy is one of the most feasible options to produce energy in countries where unexploited desert areas or solar radiation are abundant. An energy tower is an effective system for electrical power generation that can perform more efficiently along with solar radiation. As the primary aim of the present study, effects of different environmental parameters on total efficacy of energy tower were investigated. In this study, the efficiency of the energy tower system is investigated experimentally by an indoor fully adjustable apparatus. In this regard, a comprehensive set of influencing parameters like air velocity, humidity, and temperature and the effects of tower height on the performance of the energy tower are individually assessed. It is demonstrated that there is a direct relationship between an increase in humidity percentage of the surrounding and performance of energy tower, meaning that a 274% increase in humidification rate led to 43% elevation in airflow velocity. The kinetic energy increases in the direction of airflow from top to bottom, and as the height of the tower lengthens, the kinetic energy enhances and subsequently increases the overall efficiency of the tower. An elevation about 2.7% in airflow velocity was seen due to an increase from 180 to 250 cm in chimney height. Although the energy tower performs efficiently in the nighttime, airflow velocity increases averagely about 8% during the daytime and at the peak of the solar radiation, the airflow velocity enhances by 58% compared to nighttime. [ABSTRACT FROM AUTHOR]

Humidification of polymer electrolyte membranes in fuel cells is essential for high proton conductivity and lifetime, therefore often membrane humidifier modules are used. We report about the degradation of polyimide humidifier membranes under the influence of airborne ozone traces: during operation we tracked the membranes humidifier performance in 5 modules for up to 1000 h with trace levels of ozone (100 ppb) and conducted characterization tests at 200 h intervals. Operating the humidifier with ozone resulted in a linear decrease in the membrane's ability to transfer moisture over time. Moreover, the glass transition temperature of the membrane material decreases linearly with longer exposure to ozone, while the mechanical strength in terms of breaking force and elongation at break decreases too. Infrared spectra of the tested fibers showed no changes. The reduced water vapor flux would limit fuel cell performance, while the reduced mechanical properties of the membrane can lead to rupture.

Drying is the main energy consumption in the grain industry. At present, most grain drying are using machines or drying towers, but its heat loss and energy consumption is large. Some of dryers use coal as heat source and cause serious environmental pollution. In addition, the long-term storage of grain is prone to mildew and insect pests. At the same time, long-term storage of grain will lead to low water content of grain and affect the processing quality of grain. Therefore, it’s significant to realize the high-quality-low-energy consumption drying and long-term safe storage of grain to ensure the quality of exported grain. A multifunctional grain storage system with low temperature drying, refrigeration, and humidification was proposed. The equipment was developed according to the system. It had three functions such as low temperature drying mode, low temperature storage mode, and humidification mode. The equipment can realize “one-stop” grain storage and automatic control of the whole process of grain storage. The experimental results showed the air parameters of unit outlet met the design requirements in the three working modes. The average drying rates of corn and radish were about 1.1%/h and 2.9%/h, respectively. In addition, the unit can save about 19.4% of energy compared with the dryer, and 51.7% of energy compared with the condensing and dehumidifying dryer through the energy consumption analysis of the system. The driving energy of this equipment was electric, so it was eco- friendly and easy to realize the intelligent construction of granary, coming with a prospect of broad application.

Due to the increase in human population, there is an ever-increasing demand for energy in different sectors which leads to environmental problems like climate change, rise in temperature, and global catastrophes. Cooling systems have become a very essential element in recent decades for mankind. The present system focuses on the design and fabrication of a counter-flow humidification setup which uses biomass-based charcoal as the packing material. Air velocity and water flow rate have been varied along with the density of charcoal. Output parameters such as a change in pressure (ΔP), Coefficient of performance (COP), evaporation rate (ER), humidification efficiency (HE), specific cooling capacity (SCC), and energy consumption (EC) are evaluated. Performance parameters obtained for charcoal are compared with that of standard Celdek Packing. Through experiments, it is found that humidification efficiencies for Celdek and charcoal packing are 77.45% and 57.40% respectively. The overall coefficient of performance obtained is 1.41 for charcoal and 3.17 for Celdek packing. Among the three densities which were considered, charcoal packing with a density of 400 kg/m3 exhibited higher performance with respect to COP, HE, ER, and SCC. Similarly, a water flow rate of 0.4 lpm gave a maximum performance and 0.7 lpm gave the least. It is concluded that charcoal can be considered one of the highly efficient biomass-based materials contributing to sustainable energy related to cooling applications.

In light of rising fuel prices and climate change in recent decades, improving the performance of heat recovery equipment such as boiler economizers is critical. Currently, numerical work is being done to improve the performance of the economizer with spiral geometry by humidifying combustion products. Simulations are performed using the finite volume method (FVM) and, in three cases, in a two-dimensional, steady, single-phase, and turbulent condition. In the first case, water vapor condensation and liquid water spray are not considered. In the second case, the impact of water vapor condensation is considered, and the effect of liquid water spray is not considered. In the third case, the water vapor condensation and the liquid water spray are simultaneously considered. Experimental correlation relations are used to predict the condensation rate in the second and third cases. The results are presented and discussed in the form of Nusselt number, convection heat transfer coefficient (h), outlet temperature, and heat transfer rate for different inlet temperatures of combustion products. Moreover, velocity, pressure, temperature contours, and velocity vectors are obtained and analyzed. The results showed that the cold-water outlet temperature in the third case was 2.85% higher than in the first case. In addition, a maximum improvement of 1.39% in the third case is obtained compared to the second case. Also, the heat transfer rate in the third case is improved by 8.2% compared to the first case and by 3.9% compared to the second case. The proposed method in the present work can be used to predict the effect of liquid water spray on the performance of boiler economizers.

Unlike operating PEMFC systems with internal humidification from hydrogen recirculation, fuel cell stack test stations mainly rely on external humidification. Response time in the order of 10s and power over 100 kW are crucial requirements for test stations for vehicle fuel cell stacks. In the present study, a 3D computational fluid dynamics (CFD) model of a swirl spray humidifier is developed to simulate the conjugated heat and mass transfer in such a humidifier. In the model, hot, dry air enters from the bottom portion of the humidifier tangentially and mixes with liquid droplets from a nozzle placed near the middle. A discrete phase model (DPM) is employed to model the atomized droplets. Time variations of the flow structure and humidity distribution are studied. A parametric study with the nozzle parameters on humidifier performance is carried out, showing that optimal humidifier performance can be obtained with a single nozzle and spray temperature at 300 K. The humidity response at the humidifier exit subject to a load change is investigated. The simulation results show that the humidifier's dynamic response time for the baseline case is about 32s, with a steady relative humidity of 95.25% and an evaporation rate of 98.4% at the exit. The present model can guide the future design of fast-response, high-power humidifiers for fuel cell stack test stations. [Display omitted] • A CFD model of a fast-response humidifier for PEMFC test stations is developed. • The flow structure and capabilities of the humidifier are studied. • A parametric study and an investigation of the humidifier's dynamic response are carried out. [ABSTRACT FROM AUTHOR]

This research is centered around the development and construction of a test apparatus for a counterflow evaporative cooler. The packing material utilized in the testing is coconut coir with wettability values of 300, 400 and 500 m2/m3. The experiments involve varying the air velocity. The study examined performance characteristics, including evaporation rates, cooler efficiency, coefficient of performance (COP) and energy consumption information, in relation to the standard Celdek 7090 packaging. The findings demonstrated that employing a coconut coir with optimal wettability resulted in a cooling efficiency and COP of 53.57% and 1.25, respectively. These values were slightly lower than those achieved with the usual Celdek 7090 packing. Coconut coir, as a biomass-derived material, possesses certain benefits that make it a suitable alternative for filling materials in evaporative cooling processes. [ABSTRACT FROM AUTHOR]

Present work characterizes a spray tower-based desalination system, designed to simultaneously provide fresh water by condensation and supply dehumidified air to occupied spaces. Its configuration is open air-open water, with Celdek 7090 packing in the humidification section and water-cooled helical coils for dehumidification. The performance parameters calculated are: gained output ratio, recovery ratio, coefficient of performance, specific electrical energy consumption, mass ratio, humidification, and dehumidification efficiency. This performance is analyzed for varying air Reynold's number and water flow rate. The best results were obtained for the sea water flow rate tested of 18 liters per hour, and showed maximum humidification efficiency, dehumidification efficiency, COP, freshwater rate, gained output ratio and concentration factor equal to 87.14%, 94.56%, 3.34, 0.9 liters per hour and 1.05, respectively. Exit air meets the thermal comfort requirements which avoids the ventilation thermal loads in the space cooling. • A spray tower desalination unit with a venturi is designed. • The maximum COP of the system is found to be 3.34 which signifies energy efficiency. • Reynolds number of 50519 & water flow rate of 18 LPH yielded maximum fresh water of 0.9 LPM. • Air supply values PMV & PPD obtained are − 0.51 & 10.41 which are within the thermal comfort range. [ABSTRACT FROM AUTHOR]

The humidity of gases is an important topic within anaesthesia and intensive care medicine. An appreciation of the underlying physics helps to ensure that we monitor and deliver optimally humidified gases to our patients, thus minimizing the pathophysiological consequences when normal humidification processes are bypassed. In this article the different techniques and equipment used to measure humidity are illustrated, as well as the methods of humidification used in clinical practice. [ABSTRACT FROM AUTHOR]

Recently, extreme climate events have become more frequent under global warming, resulting in increasingly severe disaster losses. Essentially, the variability in precipitation is more uncertain compared to temperature. In this study, monthly precipitation data from 30 stations in Qinghai Province from 1960 to 2020 were selected to investigate the spatial-temporal variations in precipitation via linear tendency estimation, variability, cumulative anomaly, Mann-Kendall test, and spatial interpolation methods. The conclusions are as follows. (1) The annual and four seasons' average precipitation in Qinghai Province showed an increasing trend over the last 61 years, and the enhancement of summer and spring average precipitation contributed more to the annual. (2) There are increasing trends from northwest to southeast in the annual and seasonal mean precipitation, whose distributions are jointly controlled by the East Asian summer monsoon (EASM), the westerlies, and geomorphological features. (3) It is reasonable to conclude that the annual and four seasons' average precipitation has increased significantly since 2003 by integrating the results of variability, cumulative anomaly, and Mann-Kendall test. In other words, the significant intensification of humidity in Qinghai since 2003 is closely related to the ongoing intensification of the EASM and the westerly wind circulation, with the latter contributing considerably. These findings confirm the view of warming and humidification in northwest China and provide a reliable time point for discussing warming and humidification in northwest China. [ABSTRACT FROM AUTHOR]

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Controlled Environment Agriculture (CEA) has become an important field of study in recent years. The objective of this research is to evaluate the growth rate of the serrano pepper crop under controlled conditions of vapor pressure deficit in a pilot-scale hydroponic greenhouse. The controlled conditions were generated with the development of a control system composed of a non-mixed crossflow heat exchanger for internal temperature and a humidification system for internal humidity control. The comparison of variables and the growth rate of the crop was carried out in a controlled and a timed greenhouse. The best growth rate for serrano pepper cultivation was obtained under the following conditions: between 4.14 and 5.42 kPa with 0.251 and 0.225 cm/day in the controlled greenhouse. The results show that it is possible to obtain higher crop growth rates by controlling the vapor pressure deficit in a pilot-scale hydroponic greenhouse, using a heat exchanger for temperature control and a humidification control system. Controlling vapor pressure deficit can be a useful tool for agriculture in CEA. [ABSTRACT FROM AUTHOR]

Because of its clean or zero-emission nature, the PEM fuel cell is considered a potential energy conversion device for power production. The performance of the PEM fuel cell is known to be influenced by many parameters, such as operating temperature, pressure, and humidification of the reactants. In addition, the operational stability of the PEM fuel cell under these conditions with the purging of water during its operation should also be studied to understand the performance of the PEM fuel cell. Therefore, this paper brings out the effects of cell humidification and cell heating on the performance, especially the operational stability concerning the liquid water removal of the PEM fuel cell. The experiments are conducted on a single PEM fuel cell with mixed flow distributors operating on different cell temperatures and humidification conditions. At dry feed operation of the PEM fuel cell at ambient condition, the cell utilizes around 80.3% of water generated for its membrane hydration, i.e., self-humidification. When the PEM fuel cell is operated at full humidification (100% RH) on both sides, the membrane is well hydrated, and the cell attains the maximum power density of 0.25 W/cm2, which is 56% more than dry feed operation. The results of the experiments at static current density demonstrate membrane hydration is the significant factor for both stable operation and efficient power output. External purging must periodically be carried out to stabilize the cell due to voltage fluctuations. The major outcome of the current study is to establish the connection between hydration and the stability of the PEM fuel cell. [Display omitted] • Membrane hydration is an essential parameter for the stability as well as the high power output. • Explores the connection between hydration and the stability of PEMFC at different conditions of humidification and cell heating. • At dry feed operation, the cell utilizes around 80% of water generated as self-humidification. • Explores the effect of purging and its impacts on the operational stability of PEM fuel cell. • Demonstrates the demand for purging due to external humidification. [ABSTRACT FROM AUTHOR]

Due to the increase in human population, there is an ever-increasing demand for energy in different sectors which leads to environmental problems like climate change, rise in temperature, and global catastrophes. Cooling systems have become a very essential element in recent decades for mankind. The present system focuses on the design and fabrication of a counter-flow humidification setup which uses biomass-based charcoal as the packing material. Air velocity and water flow rate have been varied along with the density of charcoal. Output parameters such as a change in pressure (ΔP), Coefficient of performance (COP), evaporation rate (ER), humidification efficiency (HE), specific cooling capacity (SCC), and energy consumption (EC) are evaluated. Performance parameters obtained for charcoal are compared with that of standard Celdek Packing. Through experiments, it is found that humidification efficiencies for Celdek and charcoal packing are 77.45% and 57.40% respectively. The overall coefficient of performance obtained is 1.41 for charcoal and 3.17 for Celdek packing. Among the three densities which were considered, charcoal packing with a density of 400 kg/m3 exhibited higher performance with respect to COP, HE, ER, and SCC. Similarly, a water flow rate of 0.4 lpm gave a maximum performance and 0.7 lpm gave the least. It is concluded that charcoal can be considered one of the highly efficient biomass-based materials contributing to sustainable energy related to cooling applications. [ABSTRACT FROM AUTHOR]