Search

Approximately two billion people worldwide lack access to clean drinking water, negatively impacting national security, hygiene, and agriculture. Atmospheric water harvesting (AWH) is the conversion of ambient humidity into clean water; however, conventional dehumidification is energy-intensive. Improvement in AWH may be achieved with elastocaloric cooling, using temperature-sensitive materials in active thermoregulation. Potential benefits, compared to conventional desiccant wheel designs, include substantial reductions in energy use, size, and complexity. A nickel–titanium (NiTi) elastocaloric water harvester was designed and compared with a desiccant wheel design under controlled conditions of relative humidity, air volume, and power. In a 30 min interval, the NiTi device harvested more water on average at 0.18 ± 0.027 mL/WH, compared to the 0.1567 ± 0.023 mL/WH of the desiccant wheel harvester. Moreover, the NiTi harvester required half the power input and was thermoregulated more efficiently. Future work will focus on mechanical design parameter optimization. Elastocaloric cooling is a promising advancement in dehumidification, making AWH more economical and feasible. [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]

A solid desiccant-based novel dehumidification technique in indoor cooling is a viable substitute for a traditional dehumidification system in regions with high humidity levels. The ozone layer is being steadily destroyed by vapour compression-based conventional dehumidification systems, which also have a number of other disadvantages such as excessive power consumption and a rise in the amount of chlorofluorocarbons type refrigerant leakage in the atmosphere. As compared to traditionally used vapour compression type refrigeration air conditioners, solid desiccant-integrated novel cooling may be more advantageous as it provides more easily accessible, cost-effective, and ecologically sound cooling. It can be more competitive when it is reactivated by freely available renewable heat available from solar power and industrial waste heat. Not only marginally saving energy, but it can also help in drastically lower operational costs. Recently, many studies have been carried out with aim of ameliorating desiccant air conditioners' overall performance through the development of novel system configurations, enhanced system designs and better controls, and the integration of hybrid energy sources for desiccant reactivation as well as sub-systems technological advancements. By this means, the present study offers a thorough analysis of the previously described investigations. This offers detailed study on possible suggestions and recommendations for possible future work direction based on the most recent investigations in the field of the desiccant-powered novel cooling techniques. These recommendations can help to amplify the efforts to find better solutions to concurrent technological issues, which will definitely ameliorate the overall performance of desiccant-integrated dehumidification and hybrid cooling in the field of heating, ventilation and air conditioning. [ABSTRACT FROM AUTHOR]

The objective of this paper is to provide the reliable calculation procedure for determining heat and mass flow rates for plate finned tube heat exchangers in dehumidification regimes that can be used easily in engineering practice. For this purpose, the experiments are conducted on two heat exchangers, and datasets for six more heat exchangers are used from literature. Comprehensive database is established with total of 637 sets of data, and it gathers 365 new measurement sets and 272 sets from open literature. The new calculation procedure predicts heat transfer rate and condensate flow rate where new methodology approach (based on the porous velocity, the ratio of characteristic surfaces and hydraulic diameter) is used. Predicted results show 5–10 % deviation for heat duty and up to 20 % for mass flow rate from experimental results, which is of importance to industrial practice. [ABSTRACT FROM AUTHOR]

In this study, to increase the heat and mass transfer coefficients in the system, a combination of liquid desiccant such as lithium chloride (LiCl) and hybrid nanoparticles of multi-walled carbon nanotubes (CNT-MW) Aluminum Oxide (Al2O3) and silicon oxide (SiO2) has been used. Poly-Vinyl Pyrrolidone (PVP) surface activator or surfactant has been used for complete stability of hybrid nanoparticles in lithium chloride (LiCl) desiccant solution and liquid water. By the experimental data, heat and mass transfer coefficients in the system have been determined in a relational way for different combinations of nanoparticles and adsorbents. The effect of important parameters such as air flow intensity and desiccant liquid, air temperature and humidity, temperature and composition of incoming desiccant liquid nanofluid on the efficiency of the system has been studied. And from there the exergy analysis of the system has been done. In this way, the best operating conditions for the better performance of the system containing liquid desiccant nanofluid have been determined.The results of this research have clearly shown that, changes in the air humidity and temperature have been increased by adding the hybrid nanoparticles to LiCl/H2O liquid desiccant. In this regard, the mass transfer rate has been improved from 3.41% to 28.3% and the heat transfer rate has been improved from 4.18% to 29.11%. So, the average improvement has been 23.23% and 22.22%, respectively. Adding hybrid nanoparticles to LiCl/H2O liquid desiccant has increased the mass transfer coefficient from 17.42% to 29.26% and the heat transfer coefficient from 19.83% to 33.55%. Therefore, according to these results, the average value of improvement in mass and heat transfer coefficients has been about 22.73% and 26.51%, respectively.

As global temperatures rise, droughts are becoming more frequent and severe. To predict how drought might affect plant communities, ecologists have traditionally designed drought experiments with controlled watering regimes and rainout shelters. Both treatments have proven effective for simulating soil drought. However, neither are designed to directly modify atmospheric drought. Here, we detail the efficacy of a silica gel atmospheric drought treatment in outdoor mesocosms with and without a co‐occurring soil drought treatment. At California State University, Los Angeles, we monitored relative humidity, temperature, and vapor pressure deficit every 10 min for 5 months in bare‐ground, open‐top mesocosms treated with soil drought (reduced watering) and/or atmospheric drought (silica dehumidification packets suspended 12 cm above soil). We found that silica packets dehumidified these mesocosm microclimates most effectively (−5% RH) when combined with reduced soil water, regardless of the ambient humidity levels of the surrounding air. Further, packets increased microclimate vapor pressure deficit most effectively (+0.4 kPa) when combined with reduced soil water and ambient air temperatures above 20°C. Finally, packets simulated atmospheric drought most consistently when replaced within 3 days of deployment. Our results demonstrate the use of silica packets as effective dehumidification agents in outdoor drought experiments. We emphasize that incorporating atmospheric drought in existing soil drought experiments can improve our understandings of the ecological impacts of drought. [ABSTRACT FROM AUTHOR]

The radiant systems come to the fore due to energy saving potential and good integration. The effect of different forms of cold surfaces on human thermal comfort is focused on its application. A novel natural convection-radiant evaporator for heat pumps was developed and its influence on thermal comfort was investigated. A numerical model of the chamber with the evaporator was established and verified with experimental results. Thermal comfort experiments were conducted in a climate chamber and the influence of its asymmetric and uneven cold radiation on the thermal comfort was investigated. Due to the limitation of PMV in uneven radiation situations, the revised predicted mean vote (RPMV) was proposed to assess the thermal comfort in asymmetric and uneven radiation environments based on experimental results. Based on RPMV, the influence of the surface area and temperature of the evaporator on thermal comfort was numerically analyzed. The results indicate that indoor air temperature and relative humidity, RPMV increase with the increase of plate temperature, but decrease with an increase in plate area. The most favourable indoor thermal comfort environment was obtained at an indoor air temperature of 28°C and relative humidity of 50%, which is 2°C higher than traditional air conditioning system. [ABSTRACT FROM AUTHOR]

In comfort, air-conditioning control over the humidity is essential in applications such as pharmaceutical industries, electronic gadgets manufacturing units, the food sector, paper industries, etc. Relative humidity of nearly 50% can effectively prevent the growth and abidance of biological pollutants. There are several methods using which dehumidification can be achieved. The most common method is subcooling air up to the condensation temperature of the moisture trapped and then cooling again, and the condensate is collected. This method is time-consuming and needs to be more effective. On the other hand, desiccants' dehumidification process is suitable for maintaining humidity in air-conditioning systems and producing dry air. Desiccants with economical materials, high moisture removal rate, low regeneration temperature, and steadiness after many years make a desiccant system more successful in its performance and cost. The effect of change in process air temperature, process air humidity ratio, and regeneration temperature on the system's performance is studied. This research focuses on the functioning of various desiccant dehumidification systems and their applications. A comparative study of the different dehumidification systems found efficiency, low maintenance cost, and high sustainability. [ABSTRACT FROM AUTHOR]

A double layer membrane humidity sensor was designed with a synergistic effect of force and hygroscopic expansion, capitalizing on the high sensitivity demonstrated by MXene material. This sensitivity was achieved through the modulation of resistance change associated with layer spacing of MXene. The double layer structure of sensor was made by vacuum filtration, with an inner layer of MXene for conductivity and an outer layer of cellulose nanofibers (CNF) for moisture absorption, which is rooted in the MXene through the CNFs, similar to the biomimetic structure of hairs rooted in the skin. The synergistic effect of humidity sensitivity is achieved by trapping and dissociating water molecules through the CNF layer generating a change in MXene stress and disrupting the conductive pathway of MXene upon swelling. The CNF/MXene humidity sensor showed a resistance change rate of 117.93 % from 11 % RH to 98 % RH, accompanied by a response time of 319s and a recovery time of 132s. Stable sensing performance is maintained even after 5 times adsorption and desorption cycling, prolonged exposure (7 days) or bending and folding. CNF/MXene bilayer membrane also has good electrical heating performance, reaching about 80 °C at 7V and maintaining stable performance under 5 cycles of heating and 10 min of long heating, respectively. The CNF/MXene membrane humidity sensor can monitor human respiration monitoring, fingertip humidity, pipeline leakage and artifact dehumidification, and combined with the function of electric heating can realize the cycle of dehumidification and humidity monitoring, which has a wide range of application prospects in flexible equipment. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Southeast University / Dongnan Daxue Xuebao is the property of Journal of Southeast University 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.)

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]

In this study, to increase the heat and mass transfer coefficients in the system, a combination of liquid desiccant such as lithium chloride (LiCl) and hybrid nanoparticles of multi-walled carbon nanotubes (CNT-MW) Aluminum Oxide (Al2O3) and silicon oxide (SiO2) has been used. Poly-Vinyl Pyrrolidone (PVP) surface activator or surfactant has been used for complete stability of hybrid nanoparticles in lithium chloride (LiCl) desiccant solution and liquid water. By the experimental data, heat and mass transfer coefficients in the system have been determined in a relational way for different combinations of nanoparticles and adsorbents. The effect of important parameters such as air flow intensity and desiccant liquid, air temperature and humidity, temperature and composition of incoming desiccant liquid nanofluid on the efficiency of the system has been studied. And from there the exergy analysis of the system has been done. In this way, the best operating conditions for the better performance of the system containing liquid desiccant nanofluid have been determined. The results of this research have clearly shown that, changes in the air humidity and temperature have been increased by adding the hybrid nanoparticles to LiCl/H2O liquid desiccant. In this regard, the mass transfer rate has been improved from 3.41% to 28.3% and the heat transfer rate has been improved from 4.18% to 29.11%. So, the average improvement has been 23.23% and 22.22%, respectively. Adding hybrid nanoparticles to LiCl/H2O liquid desiccant has increased the mass transfer coefficient from 17.42% to 29.26% and the heat transfer coefficient from 19.83% to 33.55%. Therefore, according to these results, the average value of improvement in mass and heat transfer coefficients has been about 22.73% and 26.51%, respectively. [ABSTRACT FROM AUTHOR]

In addressing the practical application of direct air capture (DAC) technology to achieve net-zero greenhouse gas emissions by 2050, the intricate climatic environment presents a significant challenge in selecting capture adsorbents with excellent adsorption performance, high moisture tolerance and stability. This study seeks to assess the efficacy of a temperature vacuum swing adsorption (TVSA) system for DAC, integrated with two distinct pre-dehumidification methods: condensation dehumidification and solid desiccant dehumidification. Initially, to balance enhanced adsorption capacity with the energy required for regeneration in the presence of water vapor, the optimal techno-economic performance is achieved at a 40 % relative humidity (RH). This corresponds to 15.49 GJ/t of heat consumption and 194.08 $/tonCO2 of CO2 the levelized cost of DAC (LCOD). Following dynamic simulation, the dehumidification system effectively controlled the outlet RH. Furthermore, economic analysis indicates that reducing environmental air to 40 % RH is more suitable and cost-efficient for both integrated systems. The optimal LCODs are 200.29 $/tonCO2 for the solid desiccant dehumidification system and 197.16 $/tonCO2 for the condensation dehumidification system, which could effectively save 7.09 % and 5.61 % of LCOD, respectively, compared to systems without a dehumidification process.

Abstract Objective Nontuberculous mycobacteria (NTM) are environmentally acquired opportunistic pathogens that can cause recalcitrant lung disease. Prior reports have demonstrated links between shower use and infections, yet the aerosolization of NTM from showerheads, as well as the humidity levels that may modulate NTM aerosolization from showerheads is less studied. The objective of the current study was to investigate the role of humidity in NTM aerosolization among showers in homes located in a geographic area with high lung disease incidence, Hawai’i, and test whether deployment of a dehumidifier in well-ventilated bathrooms reduce NTM exposure. Results Across two sampling events and five showers, existing NTM showerhead biofilms along with shower air were sampled at three points: pre-shower, post-shower, and post-dehumidification. In each of the sampling events, respiratory relevant NTM species were identified from shower biofilms, which were also detected in aerosolized shower air after showering events, but not after the shower was dehumidified and bathrooms vented. While sample size was small, these data suggest running a shower is a possible source of NTM aerosolization and using a commercial household dehumidifier in conjunction with opening bathroom doors and windows may be simple, cost-effective interventions to reduce environmental NTM exposures.

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]

To effectively reduce building energy consumption, a novel full fresh air system with a heat source tower (HST) and a borehole heat exchanger (BHE) was proposed for space cooling and dehumidification in this paper. The cooling system only adopts geothermal energy to produce dry and cold fresh air for space cooling and dehumidification through the BHE and HST, which has the advantage of non-condensate water compared to BHE systems integrated with a fan coil or chilled beam. Based on the established mathematical model of the cooling system, this paper analyzed the system characteristics, feasibility, operation strategy, energy performance, and cost-effectiveness of the proposed model in detail. The results show that the mathematical model has less than 10% error in estimating the system performance compared to the practical HST–BHE experimental set up. Under the specific boundary conditions, the cooling and dehumidification capacity of this system increases with the decrease in the air temperature, air moisture content, and inlet water temperature of the HST. The optimal cooling capacity and the system COP can be achieved when the air–water flow ratio is at 4:3. A case study was conducted in a residential building in Shenyang with an area of about 1800 m2. It was found that this system can fully meet the cooling and dehumidification demand in such a residential building. The operation strategy of the cooling system can be optimized by adjusting the air–water flow ratio from 4:3 to 3:2 during the early cooling season (7 June–1 July) and end cooling season (3 August–1 September). As a result, the average COP of the cooling system during the whole cooling season can be improved from 6.1 to 8.7. Compared with the air source heat pump (ASHP) and the ground source heat pump (GSHP) for space cooling, the proposed cooling system can achieve an energy saving rate of 123% and 26%, respectively. Considering that the BHE of the GSHP can be part of the proposed HST–BHE cooling system, the integration of the HST and GHSP for space cooling (and heating) is strongly recommended in actual applications. [ABSTRACT FROM AUTHOR]

Photovoltaic thermal (PVT) systems are attracting a significant amount of attention in research because they can generate electricity outside of daytime hours, unlike photovoltaic (PV) systems, and can increase efficiency and collect additional energy by reducing the temperature of PVT panels. However, a somewhat lower amount of collected energy is used in the summer than in the winter, and research on this issue is lacking. In this study, first, we experimentally evaluated the performance of PV and PVT systems by season and verified the improvement in the performance of the PVT system. Second, experiments were conducted to verify the enthalpy reduction via mist cooling and dehumidification, and the temperature and humidity control effect via mist cooling and dehumidification was verified. Based on our research findings, we propose a model that can be integrated with indoor ventilation systems to increase the solar energy utilization of PVT systems. Using the PVT system, we improved the panel power generation efficiency by up to 5.89% and generated up to a 38.0% higher collection efficiency than that of the PV system. The air that passed through the PVT system was then subjected to mist cooling and dehumidification to reduce its temperature and increase its humidity, resulting in a 23.2% reduction in enthalpy. [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]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology 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.)

Objective: Nontuberculous mycobacteria (NTM) are environmentally acquired opportunistic pathogens that can cause recalcitrant lung disease. Prior reports have demonstrated links between shower use and infections, yet the aerosolization of NTM from showerheads, as well as the humidity levels that may modulate NTM aerosolization from showerheads is less studied. The objective of the current study was to investigate the role of humidity in NTM aerosolization among showers in homes located in a geographic area with high lung disease incidence, Hawai'i, and test whether deployment of a dehumidifier in well-ventilated bathrooms reduce NTM exposure. Results: Across two sampling events and five showers, existing NTM showerhead biofilms along with shower air were sampled at three points: pre-shower, post-shower, and post-dehumidification. In each of the sampling events, respiratory relevant NTM species were identified from shower biofilms, which were also detected in aerosolized shower air after showering events, but not after the shower was dehumidified and bathrooms vented. While sample size was small, these data suggest running a shower is a possible source of NTM aerosolization and using a commercial household dehumidifier in conjunction with opening bathroom doors and windows may be simple, cost-effective interventions to reduce environmental NTM exposures. [ABSTRACT FROM AUTHOR]

Abstract As global temperatures rise, droughts are becoming more frequent and severe. To predict how drought might affect plant communities, ecologists have traditionally designed drought experiments with controlled watering regimes and rainout shelters. Both treatments have proven effective for simulating soil drought. However, neither are designed to directly modify atmospheric drought. Here, we detail the efficacy of a silica gel atmospheric drought treatment in outdoor mesocosms with and without a co‐occurring soil drought treatment. At California State University, Los Angeles, we monitored relative humidity, temperature, and vapor pressure deficit every 10 min for 5 months in bare‐ground, open‐top mesocosms treated with soil drought (reduced watering) and/or atmospheric drought (silica dehumidification packets suspended 12 cm above soil). We found that silica packets dehumidified these mesocosm microclimates most effectively (−5% RH) when combined with reduced soil water, regardless of the ambient humidity levels of the surrounding air. Further, packets increased microclimate vapor pressure deficit most effectively (+0.4 kPa) when combined with reduced soil water and ambient air temperatures above 20°C. Finally, packets simulated atmospheric drought most consistently when replaced within 3 days of deployment. Our results demonstrate the use of silica packets as effective dehumidification agents in outdoor drought experiments. We emphasize that incorporating atmospheric drought in existing soil drought experiments can improve our understandings of the ecological impacts of drought.

Approximately two billion people worldwide lack access to clean drinking water, negatively impacting national security, hygiene, and agriculture. Atmospheric water harvesting (AWH) is the conversion of ambient humidity into clean water; however, conventional dehumidification is energy-intensive. Improvement in AWH may be achieved with elastocaloric cooling, using temperature-sensitive materials in active thermoregulation. Potential benefits, compared to conventional desiccant wheel designs, include substantial reductions in energy use, size, and complexity. A nickel–titanium (NiTi) elastocaloric water harvester was designed and compared with a desiccant wheel design under controlled conditions of relative humidity, air volume, and power. In a 30 min interval, the NiTi device harvested more water on average at 0.18 ± 0.027 mL/WH, compared to the 0.1567 ± 0.023 mL/WH of the desiccant wheel harvester. Moreover, the NiTi harvester required half the power input and was thermoregulated more efficiently. Future work will focus on mechanical design parameter optimization. Elastocaloric cooling is a promising advancement in dehumidification, making AWH more economical and feasible.

The cable room, located at the base of the ring main unit, is prone to water vapor due to its proximity to damp cable holes and its relatively enclosed structure. This may penetrate internally and ultimately affect operational safety. Therefore, a dehumidifier was introduced to utilize dry air for internal circulation. To enhance the dehumidification in the cable room, the cable room device was designed for experimental research. Meanwhile, computational fluid dynamics (CFD)-electromagnetic (EMAG) coupling simulation is used to calculate the power loss of heat sources and their influence on multiple physical fields in numerical simulations. The feasibility of this study was confirmed by comparing the relative humidity, temperature, and velocity values between the experimental and numerical approaches. Furthermore, the layout of the ventilation pipes was modified to a vertical distribution, with upward supply and downward suction, to improve the airflow. The results indicate that the maximum relative errors in temperature, relative humidity, and velocity are only 3.61%, 7.14%, and 7.14%, respectively, which fall within an acceptable range. On this basis, additional simulation analysis was conducted on the humidity, dew point temperature, and airflow within the cable room, using an optimized model with a more comprehensive internal structure and cables. After implementing an optimized ventilation pipe layout, the relative humidity at the corresponding measuring points can decrease by up to 10.6%. The dew point temperature has decreased by 2.61 °C and the airflow has become more stable. [ABSTRACT FROM AUTHOR]

• Polymer desiccant wheel with high water uptake and low regeneration temperature is studied. • Polymer's adsorption capacity of 1.15 g kg−1 at 90 %RH is five times that of silica gel. • Polymer's desorption rate coefficient is 1.32–1.64 times that of silica gel at 40–70 °C heat sources. • The maximum ∆ Y and DCOP of the polymer desiccant wheel are 4.0 g kg−1 and 0.66, respectively. • Polymer desiccant wheel offers a promising measure for ultra-low dew point humidity control. Desiccant wheels have been widely used in humidity control, particularly under conditions with ultra-low dew point temperatures. However, traditional desiccants such as silica gel and zeolites are subject to relatively low adsorption capacity and high regeneration temperature. To address these challenges, a type of polymer material with high water uptake and low regeneration temperature is investigated in this paper. Firstly, the adsorption/desorption capacity of this polymer is thoroughly tested. Results reveal that its remarkable equilibrium adsorption capacity and desorption rate coefficients k LDF,de are 350% and 32–64% higher than that of silica gel, respectively. Moreover, its required regeneration temperature is just about 40–70 °C. The performance of the desiccant wheel using this polymer is simulated by a model validated by experiments tests. Parameter analysis demonstrates that the desiccant wheel is suitable for cool and humid conditions, reaching the maximum moisture removal (∆ Y) and dehumidification coefficient of performance (DCOP) of 4.0 g kg−1 and 0.66, respectively. Furthermore, the corresponding relationship between other parameters and the optimal rotation speed is discussed in detail. The ω opt is around 18 rph, enabling the attainment of the highest ∆ Y. Finally, the performance comparison with a traditional silica gel desiccant wheel is carried out. The results indicate that the polymer one performs 17–53.9% higher in terms of both ∆ Y and DCOP than the silica gel counterpart. And the most significant improvement is observed in low relative humidity conditions (45%RH), where ∆ Y and DCOP are 1.25–1.53 times that of the silica gel's, highlighting the advantageous utilization of the polymer material. [ABSTRACT FROM AUTHOR]

The use of a liquid desiccant air dehumidifier is an energy-efficient technology that can improve both indoor air temperature and humidity. However, the risk of concentrated liquid desiccant leakage into the air conditioning system during dehumidification can corrode the system, negatively impact indoor air quality, and potentially harm residents. To address this issue, this study investigates the effectiveness of osmotic distillation (OD) and direct contact membrane distillation (DCMD) for dehumidification and regeneration, respectively. The study analyzes the impact of inlet operating parameters, including liquid desiccant concentration, temperature, and flow rate, and air flow rate on the dehumidification performance and stability of the OD process. Calcium chloride was utilized as the liquid desiccant in this study. The results indicated that the dehumidification performance of the OD process improved with a higher desiccant concentration and lower desiccant temperature. However, the desiccant flow rate did not have a significant impact on dehumidification performance. Furthermore, the dehumidification performance decreased with a higher inlet air flow rate, but the moisture removal rate increased. The OD process demonstrated stable operation during the dehumidification process. DCMD was effective for desiccant regeneration, and no scaling occurred due to the deposition of calcium chloride crystals. However, the permeation flux of DCMD decreased as the feed concentration increased due to a decline in the feed vapour pressure and an increase in concentration polarization effect. In conclusion, the experimental results indicated that OD can effectively dehumidify humid air, while DCMD is a viable option for desiccant regeneration. • Osmotic distillation (OD) was used for air dehumidification. • Direct contact membrane distillation (DCMD) was used for desiccant regeneration. • PVDF HF membrane was applied to OD and DCMD systems. • Operating parameters of the OD system were studied for air dehumidification. • Regeneration performance of calcium chloride liquid desiccant was examined. [ABSTRACT FROM AUTHOR]

The main goal of this research is to use zeolite TiO2 nanocomposite membranes in order to remove moisture from gas. For this reason, a certain TiZ-V membrane was selected and manufactured as a standard membrane, which was the result of the initial assessment of a suitable membrane for gas dehumidification, and this membrane was used as a standard to measure the effect of manufacturing parameters. The findings showed that increasing the concentration of SiO2 had greatest effect on increasing the water flux of the membrane due to the effect of increasing the reaction time of the vapor phase carrier and reducing the selectivity drop at higher pressures. Also, the experiments of changing the relative humidity of the feed have shown the improving efficiency of the membrane in relative humidities lower than 80%, so that under the conditions of lower relative humidity, the selectivity of the membrane has increased. Another positive point found is a slight change in the selectivity efficiency of the membrane with respect to different relative humidities. This case showed the stability of membrane performance under the different conditions of humidity of the feed gas. Next, in order to increase the performance of membrane as much as possible, the sweeper gas was added from the inside of membrane. Increase in the sweeper gas, which increases the water concentration gradient and decreases the gas concentration gradient on the sides of membrane wall, increases the selectivity of membrane to the highest level of 543. [ABSTRACT FROM AUTHOR]

The main goal of this research is to use zeolite TiO2 nanocomposite membranes in order to remove moisture from gas. For this reason, a certain TiZ-V membrane was selected and manufactured as a standard membrane, which was the result of the initial assessment of a suitable membrane for gas dehumidification, and this membrane was used as a standard to measure the effect of manufacturing parameters. The findings showed that increasing the concentration of SiO2 had greatest effect on increasing the water flux of the membrane due to the effect of increasing the reaction time of the vapor phase carrier and reducing the selectivity drop at higher pressures. Also, the experiments of changing the relative humidity of the feed have shown the improving efficiency of the membrane in relative humidities lower than 80%, so that under the conditions of lower relative humidity, the selectivity of the membrane has increased. Another positive point found is a slight change in the selectivity efficiency of the membrane with respect to different relative humidities. This case showed the stability of membrane performance under the different conditions of humidity of the feed gas. Next, in order to increase the performance of membrane as much as possible, the sweeper gas was added from the inside of membrane. Increase in the sweeper gas, which increases the water concentration gradient and decreases the gas concentration gradient on the sides of membrane wall, increases the selectivity of membrane to the highest level of 543. [ABSTRACT FROM AUTHOR]

• Spherical membrane-based micro-absorbers were produced using microfluidics setup. • The proposed micro-absorbers offer surface-to-volume ratios up to 12,000 m2/m3. • The design overcomes challenges such as solution carryover and crystallization. In this work, a novel design concept for absorbers used in dehumidification systems is proposed to overcome the practical challenges of the conventional packed-column absorbers. In the proposed design, spherical micro-absorbers (microcapsules) that contain a liquid LiBr desiccant inside a semi-permeable polymeric membrane shell are produced by using a custom-built microfluidic technique. The produced microcapsules are capable of containing the salt during crystallization. The X-ray diffraction analysis has confirmed that the observed crystals in the microscopes images were indeed for the encapsulated (LiBr) salt. Due to the indirect contact between the liquid desiccant and the process air, problems such as solution carryover and corrosion associated with packed-column absorbers can be eliminated. The collected sorption data show that the spherical microcapsules offer a high sorption capacity of 1 g w /g dry under 80% relative humidity. The proposed microcapsules offer surface-to-volume ratios between 6,000–12,000 m2/m3, which is up to two orders of magnitude higher than the conventional packed-column absorbers (200–600 m2/m3). The produced micro-absorbers can withstand a compression force up to 2 × 105 their weight, elastically expanded during the absorption process without rupture, and did not show a leakage or a reduction in capacity even after an accelerated test of 200 sorption-desorption cycles. [ABSTRACT FROM AUTHOR]

In this study, a new polymer membrane was developed for natural gas dehumidification using the combination of hydrophilic silica nanoparticles in the Pebax polymer matrix. The membranes were characterized using various analytical methods including FTIR, XRD, SEM, and TGA. The results indicated that adding nanoparticles increased the porosity and thermal stability of the membranes. Also, the enhancement of copolymer hydrophilicity was confirmed by reducing contact angles. The study found that increasing the nanoparticle content from 0 w% to 3 w% at 15 bar pressure resulted in a 33% increase in water permeability and a 12% increase in methane permeability. Adding of silica also increased the H2O/CH4 selectivity from 24.17 to 27.34. Moreover, at higher temperatures (from 25 to 55°C), the permeability of H2O and CH4 reached 171.3 and 10.71 bar, respectively. The findings of this study show that the inclusion of hydrophilic silica nanoparticles in the Pebax matrix can enhance the efficiency of membranes for natural gas dehumidification. Additionally, the study highlights the significance of temperature in the design and implementation of such membranes [ABSTRACT FROM AUTHOR]

Efficient dehumidification has been one of the technical problems to restrict the high-quality development of the greenhouse industry in China. It is a high demand to dehumidify and recover the heat energy in the process of dehumidification during winter. Among them, the airside heat and moisture transfer properties of finned-tube evaporators have had direct impacts on the performance of the entire dehumidification system in the greenhouse. In this study, the heat transfer models were established for the evaporators under both low temperatures and high relative humidity. Four hydrophilic finned-tube evaporators were taken with the plain fin, the plain fin with vortex generator, wavy fin, and slit fin. The numerical simulation was verified to compare the experimental data. The heat and moisture transfer properties of four evaporators were assessed for the refrigeration dehumidification systems in the greenhouse using various parameters, including the heat transfer capacity, Nusselt number, friction factor, dehumidification capacity per area, and the enhanced heat-transfer factor. The results showed that average relative errors of less than 3% were achieved in the Nusselt number and friction factor of the models for the grid system. There were the higher Nusselt number, heat transfer capacity, friction factor of the air side in the plain fin with vortex generator, the wavy fin, and the slit fin, compared with the plain fin. The largest heat-transfer capacity and friction factor of the slit fin were achieved under the same inlet air velocity and relative humidity conditions. The friction factor also decreased significantly with the increase of inlet air velocity, with an average decrease of 26.06%, 24.87%, 21.10%, and 29.06%, respectively. By contrast, there was a relatively small effect of the relative humidity on the friction factor. The slit fin exhibited the highest heat transfer capacity and friction factor, whereas, the plain fin displayed the lowest under the same conditions. The other three types of fins improved the convection heat transfer on the air side of the evaporator, due to their unique structure. The dehumidification capacity was augmented with the rise in the inlet air velocity and relative humidity. The wavy fin shared the greatest average increase in the dehumidification capacity per area, with 8.68% and 7.60%, respectively, at inlet air velocity and relative humidity. The wavy fin-tube evaporator presented the highest average enhanced heat transfer factor of 1.084 and 1.041, respectively, under the conditions of inlet air velocity and relative humidity, indicating the most favorable heat and moisture transfer properties. Hence, the wavy fin-tube evaporator was recommended for dehumidification at low temperatures and high relative humidity in the winter of cold regions, when the inlet air velocity exceeded 2 m/s and the relative humidity was over 80% in the greenhouse environment. The findings can provide a strong reference for the design and application of the hydrophilic finned-tube evaporators in the refrigeration dehumidification systems in the greenhouse. [ABSTRACT FROM AUTHOR]

• Desiccant wheel's performance. • The desiccant wheel's performance has been evaluated using a new set of independent efficacy metrics. • the effects of operational factors on the performance parameters. • Correlations have been developed based on experimental data for forecasting desiccant wheel performance. • There is a high degree of agreement between experimental and anticipated results when using the correlations suggested. In order to utilize green energy and reduce the environmental effect of traditional systems, the majority of HVAC experts are now focusing on the development of sustainable and green energy-supported air conditioning technologies. The air conditioning technologies integrated with a desiccant wheel can save energy and reduce the environmental influence. The desiccant wheel is essential for every rotary desiccant integrated air conditioning system. A practical cooling system with a desiccant wheel requires much effort to analyze. But the performance of a desiccant wheel can be predicted effectively using suitable performance parameters, which is the focus of this study. The desiccant wheel's performance has been evaluated using a new set of independent efficacy metrics. Several types of research have been conducted to determine the effects of operational factors on the performance parameters. Correlations have been developed based on experimental data for forecasting desiccant wheel performance. There is a high degree of agreement between experimental and anticipated results when using the correlations suggested. [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 majority of household energy is consumed in heating and air conditioning. Desiccant disks are a way to harvest renewable solar energy or waste heat for air conditioning. In the literature there is a gap in the investigation of start-up of desiccant dehumidifiers, which this paper attempts to covers. For this work, a desiccant disk was designed, manufactured, and tested. To reduce the cost, off-the-shelf components were used as structure materials. And as adsorption material, widely available materials were used. Input heat was simulated by an electrical heater and power to auxiliary motors was provided in the form of DC power. Temperature and humidity were recorded at various locations using DHT11 sensors. The system was turned off and tested at a start of operation mode. The performance of the desiccant disk was quantified by the coefficient of performance and the dehumidification efficiency. Results showed gradual increase of the desiccant disk efficiency with a maximum COP value of 0.4 reached within 10 min of the start of operation. Time delays were attributed to heating of the disk. Further work is required to fully understand the transient operation.

Data center is one of the indispensable infrastructures in the modern information society; however, its high energy consumption and carbon emission have become an urgent problem. In order to reduce the large energy consumption of data centers in hot and humid areas due to mechanical cooling and air-conditioning systems, the operation of an indirect evaporative cooling (IEC) air-conditioning system was simulated in a hot and humid area data center based on Matlab and the EnergyPlus platform, and its annual energy consumption was evaluted. The impact of solar-assisted liquid desiccant dehumidifier (LDD) system on the three operation modes and the performance of IEC air-conditioning system were also investigated. The results show that the IEC air-conditioning system can achieve 16.5% annual energy saving intensity compared to a conventional mechanical cooling system, and that the addition of an LDD unit can increase the wet mode operating time of the IEC air-conditioning system by 35.9% and reduce the system energy consumption by 20.1%. Therefore, IEC air-conditioning systems have significant energy-saving advantages in hot and humid data centers and can significantly improve the operational efficiency and sustainability of data center air-conditioning systems.

In this study, the sensitivity of a novel dehumidification requirement model (DehumReq) is analyzed to evaluate the effect of the predominant factors on the dehumidification needs of the greenhouses. The hourly dehumidification demand and sensitivity coefficient (SC) are estimated for three different seasons: warm (July), mild (May), and cold (November), by using the local sensitivity analysis method. Based on SC values, the solar radiation, air exchange, leaf area index (LAI), and indoor setpoints (temperature, relative humidity (RH), and water vapor partial pressure (WVPP)) have significant impact on the dehumidification needs, and the impact varies from season to season. Most parameters have a higher SC in summer, whereas solar radiation and LAI have a higher SC in mild season. The dehumidification load increases 4 times of its base value with increasing solar radiation by 200 W/m2, and the highest LAI (10) caused 5 times increment of the load. The changing of WVPP from its base value (1.5 kPa) to maximum (2.9 kPa) reduces the load 70% in summer. Air exchange was found to be the most crucial parameter because it is the main dehumidification approach that has a large range and is easily adjustable for any greenhouses. Sufficient air exchange by ventilation or infiltration will reduce the dehumidification load to zero in May and November and minimizes it to only nighttime load in July. For the other parameters, higher ambient air RH and indoor air speed will result in higher the dehumidification load; whereas higher inner surface condensation will result in lower dehumidification load. The result of this study will assist in the selection of the most efficient moisture control strategies and techniques for greenhouse humidity control.

The polymer desiccant cooling system (PDCS) efficiently reduces energy consumption compared to the vapor compression system (VCS). In this paper, a PDCS integrated heat pump is proposed. Experimental and simulation are used to analyze the performance of the PDCS. The control strategy is optimized with the NSGA Ⅱ algorithm. A case study in Shanghai illustrates the practical application of the PDCS optimization strategy. The calculation results based on the thermal comfort requirement show the maximum energy consumption of optimized PDCS, routine PDCS, and VCS are 549.9 kW, 597.7 kW, and 1327.7 kW. About 62.7 % and 72.3 % of energy can be saved in routine PDCS and optimized PDCS compared to VCS. Moreover, the maximum moisture removal efficiency of the above scenarios is 10.67 kW/(g·s), 11.56 kW/(g·s), and 25.42 kW/(g·s), separately. Additionally, the maximum coefficient of performance is 0.530, 0.457, and 0.182, respectively.

Air-conditioning system applies dehumidification by condensation technique, where the cooling coil handles both latent and sensible load. Energy consumption by the system increases by handling both loads. In order to reduce operating energy and load on cooling coil, latent load needs to be reduced or eliminated. Latent load can be handled separately using desiccant-type dehumidifiers irrespective of cooling coil temperature. This paper investigates the dehumidification performance of a desiccant wheels (DWs) made of fiber paper substrates such as Ceramic Fiber, Glass Fiber, Wood Pulp Fiber, Nomex Fiber, and Brown Wood Pulp Paper (BWPP) coated with synthesized mesoporous nano-titania desiccant for energy-efficient air-conditioning. Moisture adsorption ability test was conducted for different fiber papers at 30 °C and 75% RH, where BWPP has maximum moisture adsorption of 38 g m−2 and 0.42 g g−1 due to its hydrophilic nature, with the highest coating ratio of 3.5 g cm−3. The thermal conductivity, nitrogen adsorption/desorption isotherm, pore structure, and thermal stability of the fiber substrates were also analyzed before and after coating. The thermal conductivity of the fiber papers coated with nano-titania desiccant has enhanced compared to the raw fiber papers, and it reaches 0.116 W m−1 K−1 for BWPP. The dehumidification coefficient of performance of BWPP–DW at a 1:1 airflow area ratio, 60 °C regeneration temperature, and 10 rph is 0.82. The BWPP matrix DWs can be reactivated by low-grade energy sources with 0.82 kg kW−1 h−1 and saves energy up to 2.39 times. [ABSTRACT FROM AUTHOR]

An air-conditioning system (ACS), which consumes large amounts of high-grade energy, is essential for maintaining the indoor thermal environment of modern buildings. However, an ACS consumes almost half of the total energy of the building. Therefore, it is necessary to reduce the energy consumption of the ACS to promote energy conservation and emission reduction in the building sector. In fact, there is an abundance of waste heat and low-grade energies with the potential to be utilized in ACS in nature, but many of them are not utilized efficiently or cannot be utilized at all due to the low efficiency of thermal energy conversion. Known as a passive thermal transfer device, the application of a heat pipe (HP) in the ACS has shown explosive growth in recent years. HPs have been demonstrated to be an effective method for reducing building cooling and heating demands and energy consumption in ACS with experimental and simulation methods. This paper summarizes the different HP types applied in the ACS and provides brief insight into the performance enhancement of the ACS integrated with HP. Four types of HPs, namely tubular HP (THP), loop HP (LHP), pulsating HP (PHP) and flat HP (FHP), are presented. Their working principles and scope of applications are reviewed. Then, HPs used in natural cooling system, split air conditioner (SAC), centralized ACS (CACS) and cooling terminal devices are comprehensively reviewed. Finally, the heat transfer characteristics and energy savings of the above systems are critically analyzed. The results show that the performance of the HP is greatly affected by its own structure, working fluid and external environmental conditions. The energy saving of ACS coupled with HP is 3–40.9%. The payback period of this system ranges from 1.9–10 years. It demonstrates that the HP plays a significant role in reducing ACS energy consumption and improving indoor thermal comfort. [ABSTRACT FROM AUTHOR]

By combining the advantages of desiccant dehumidification and vapor compression refrigeration, the desiccant-coated heat exchanger-based heat pump (DCHE HP) is regarded as a promising alternative to the traditional vapor-compression air conditioning system (VCAC). Selecting proper desiccants from a large number of candidates is of great importance to improve the performance of DCHE HP. However, this task is challenging using current experimental or modelling strategies. In this work, we developed an equilibrium model to evaluate the power consumption of 39 DCHE HPs coated with different desiccants under various operating conditions. Eventually, five desiccants with low power consumption were selected. It was also demonstrated that under given operating conditions, the DCHE HP based on the five selected desiccants can save 21.3%–32.9% power compared with the VCAC. The power consumption of the DCHE HP is largely dependent on the heat of adsorption, the cyclical water uptakes and the remained moisture contents of the coating desiccants. It was further revealed that the moderate heat of adsorption, the larger cyclical water uptake and the lower remained moisture content are preferable for reducing the system energy demand. This work reported a quick evaluation of 39 desiccants for DCHE HP by an equilibrium model, which may also offer insights into the choosing and designing of desiccants for DCHE HP. [ABSTRACT FROM AUTHOR]

Liquid desiccant systems are promising methods to recover water and waste heat simultaneously from flue gas. Prior research found that the reduction of particulate matter could occur during the absorption processes. In the present paper, experiments were carried out to explore the effect of removing fine particulate matter (PM2.5) in a liquid desiccant dehumidifier. Aqueous calcium chloride (CaCl2) was used as the desiccant in the experiments. The discrepancies in mass and energy conservation were within ±10% and ±15%, respectively, which showed the good reliability of the experimental results. Additionally, 23.5%–46.0% of the PM2.5 and 23.9%–45.1% of the moisture in the flue gas were removed. By comparing the desiccant solution and water, it was found that they could minimally remove PM2.5 through washing the flue gas. Regardless of whether the flue gas was dehumidified by water or the solution, the removal fractions of PM2.5 of these two methods could be very close if they achieve the same fraction of moisture removal. From the results of a parameter analysis, it was found that the removal fraction of PM2.5 was nearly proportional to the removal fraction of moisture within the experimental range. [ABSTRACT FROM AUTHOR]

• Dehumidification performance of polymer composite desiccants were compared. • PVA/PEO/LiCl ratio and thickness with the greatest performance were mastered. • Cycling performance of PVA/PEO/LiCl remains unchanged after numerous tests. • Mechanism of dehumidification of PVA/PEO/LiCl has been discovered. Composite desiccants have led to a growing interest because of their eco-friendliness, sustainability, and excellent dehumidification properties. In this paper, we present a method for constructing a dehumidification composite of PVA/PEO/LiCl that is eco-friendly and recyclable. The results show that PVA/PEO/LiCl has better dehumidification performance than SG, SG/LiCl, PVA/PEO, and PVA/PEO/CaCl 2 as coated heat exchangers desiccants. The addition of LiCl caused the internal hydrophilic polymeric hygroscopic carriers to work in concert with the membrane porosity. This resulted in a considerable increase in the membrane's hygroscopic rate and capacity, as well as improved mechanical qualities. As the concentration of LiCl was increased, the surface sealing of the PVA/PEO polymer improved dramatically, and the shape of the polymer-formed film changed from loose to firmly packed. The structural shift toward densification boosted the strength of the co-blended dehumidified films. With a PVA/PEO/LiCl ratio of 1:1:2.5 and the coating thickness of 10–15 µm, the greatest dehumidification effectiveness is achieved. During five subsequent sorption and desorption procedures, the sorption of PVA/PEO/LiCl remained between 70 and 75%, demonstrating its outstanding reusability and cycling stability. [Display omitted] [ABSTRACT FROM AUTHOR]

The water sorption and desorption properties of solid adsorbent materials are crucial in rotary dehumidification systems. Metal organic frameworks (MOFs) and hydrogels are mostly at the laboratory stage due to factors like the synthesis process and yield. In this study, we utilized an eco-friendly and large-scale synthesis method to prepare polyacrylamide (PAM) hydrogels (yielding approximately 500 mL from a single polymerization). Subsequently, PAM was then coated onto glass fiber paper (GFP), which serves as a commonly employed substrate in desiccant wheels. By incorporating the hygroscopic salt LiCl and optimizing the content of each component, the water sorption performance of the composite was notably improved. The water sorption and desorption performances, as well as cycling stability, were evaluated and compared with composites containing aluminum fumarate, LiCl, and GFP (AlFum-LiCl&GFP). The results revealed that PAM-LiCl&GFP outperformed AlFum-LiCl&GFP in terms of sorption capacity throughout various relative humidity (RH) levels. It achieved a water uptake of 1.06 g·g−1 at 25 °C and 30% RH, corresponding to a water sorption rate coefficient K of 15.32 × 10−4 s−1. Furthermore, the lower desorption temperature (60 °C) resulting in a desorption ratio of 82.6%, along with the excellent cycling stability and effective performance as a desiccant wheel module, provide evidence for the potential application of PAM-LiCl&GFP in desiccant wheels. [ABSTRACT FROM AUTHOR]

Desiccant agents (DAs) have drawn much interest from researchers and businesses because they offer a potential method for lowering environmental impact, increasing energy efficiency, and controlling humidity. As a result, they provide a greener option to conventional air conditioning systems. This review thoroughly analyzes current issues, obstacles, and future advancements in liquid desiccant agents (LDAs) for drying, air conditioning, and dehumidification applications. The importance of LDAs in lowering energy use and greenhouse gas emissions is highlighted, emphasizing their potential for environmentally friendly humidity control. The current review examines key parameters such as novel materials, enhancing desiccant qualities, integration with technologies, and long-term durability while examining recent developments in LDAs and investigating their applications in diverse industries. The main conclusions from the evaluated publications in this review are also highlighted, including developments in LDAs, new applications, and developing research fields. Overall, this review advances knowledge of LDAs and their potential to shift humidity control systems toward sustainability and energy efficiency. [ABSTRACT FROM AUTHOR]

Humidity control is relevant to many processes in buildings and manufacturing and is responsible for over 600 million tons of CO2 annually. As such, desiccants that can efficiently remove moisture from air can greatly reduce emissions. A new class of desiccant materials, thermo‐responsive desiccants, has been of increased interest in the literature. These materials are generally based on thermo‐responsive polymers and exhibit a temperature‐dependent isotherm, an attribute that is small in traditional desiccants. In this work, seven key parameters needed to create an effective thermo‐responsive polymer desiccant are identified using a combination of modeling and experimental data. It is found that more thermo‐responsiveness is not necessarily better for energy efficiency, and that an optimal, "medium" value is desired. Additionally, polymer composition and architecture play key roles in adjusting the seven key parameters. Finally, based on findings from both modeling and experimental work, guidelines on synthesizing future thermo‐responsive polymer desiccants are presented. [ABSTRACT FROM AUTHOR]

Data center is one of the indispensable infrastructures in the modern information society, however, its high energy consumption and carbon emission have become an urgent problem. In order to reduce the large energy consumption of data centers in hot and humid areas due to mechanical cooling and air-conditioning systems, the operation of an indirect evaporative cooling (IEC) air-conditioning system was simulated in a hot and humid area data center based on Matlab and the Energy Plus platform, its annual energy consumption was evaluted. The impact of solar assisted dehumidification (LDD) system on the three operation modes and the performance of IEC air-conditioning system were also investigated. The results show that the IEC air-conditioning system can achieve 16.5% annual energy saving intensity compared to a conventional mechanical cooling system, and that the addition of an LDD unit can increase the wet mode operating time of the IEC air-conditioning system by 35.9% and reduce the system energy consumption by 20.1%. Therefore, IEC air-conditioning systems have significant energy-saving advantages in hot and humid data centers and can significantly improve the operational efficiency and sustainability of data center air-conditioning systems. [ABSTRACT FROM AUTHOR]

The different adsorption applications require the development of sorbents with predetermined properties. One of the ways for fine tuning the adsorption properties of the material is using a binary salt system as an active sorbing component. The aim of this work is to conduct a precision investigation of thermodynamic data on the sorption equilibrium of composite sorbents "(CaCl2 + CaBr2) confined to the silica gel pores" with water vapour. The isotherms and isosteres (at an uptake of N = 1.5 and 3.6 mole/mole) of water sorption on the composites were measured. It was shown that at a fixed temperature, the composites based on solid solutions of CaCl2 in CaBr2 form complexes with water at a pressure that is dependent on the CaCl2/CaBr2 molar ratio. The isosteric enthalpy and entropy of water sorption (ΔH = −48 ± 3 kJ/mol ΔS = −108 ± 2 J/(mol·K)) at N = 3.6 mole/mole were midway between the same parameters for composites on the base of the pure salts CaCl2 and CaBr2. The novelty of this work is in the design of sorbents optimized for air conditioning in hot climates and air drying cycles. It was shown that the use of the binary CaCl2 + CaBr2 system confined to the silica pores can be an effective tool for designing innovative materials with predetermined properties. [ABSTRACT FROM AUTHOR]