Dehumidification Effectiveness Research Articles

Study on the Temperature and Water Distribution of Hot Air in Red Loam Based on Soil Continuous Cropping Obstacles

In recent years, the problematic circumstances of the constant cropping problem in facility crops have become increasingly serious. Compared to chemical disinfection, soil steam disinfestation offers the benefits of environmental protection and being pollution-free, which can effectively reduce the problem of constant cropping in crops. However, during the steam disinfection procedure, a large quantity of liquid water is formed due to the condensation of high-temperature steam, which causes soil pore blockage, seriously affecting the mass and heat transfer efficacy of steam and, thus, affecting the disinfection efficiency. Therefore, to solve this problem, this paper proposes the use of hot air dehumidification to remove excess water from soil pores and achieve the goal of dredging the pores. However, further exploration is needed on how to efficiently remove excess water from different pore structures through hot air applications. Therefore, this paper first used CFD simulation technology to simulate and analyze the hot air flow field, mass, and heat transfer in soil aggregates of different sizes (<2 mm to >8 mm). Then, based on the soil hot air heating experimental platform, research was conducted on the mass and heat transfer mechanism of hot air under diverse soil pore conditions. The results show that as the soil particle size increases from <2 mm to >8 mm, the number of soil macropores also increases, which makes the soil prone to the formation of macropore thermal currents, and the efficiency of hot air heating for dehumidification first increases and then decreases. Among them, the 4–6 mm treatment has the best dehumidification effect through hot air heating, with a deep soil temperature of up to 90 °C and a water content reduction of 6%. The 4–6 mm treatment has a high-temperature heating and dehumidification area of 15–20 cm deep. The above results lay the theoretical foundations for the parameters of hot air heating and dehumidification operations, as well as the placement of the hot air pipe. This paper aims to combine hot air dehumidification technology, for the removal of excess water from soil, and dredging soil pores, ultimately achieving the goal of improving soil steam disinfection efficiency.

Modified efficiency-NTU method (m-ε-NTU) for calculating air coolers in dehumidifying or frost conditions. Part IV

In the fourth part of the article, the algorithm for applying the newly developed the m-ε-NTU method for calculating air coolers in dehumidifying or frost conditions is described step by step, and its comparison with the method of segmented division of the heat exchanger is also given. This comparison showed good convergence of the calculation results with a multiple reduction in their execution time. The value of the deviation of the calculated value of thermal power calculated using the newly developed method from the same value calculated using the method of segmented division averaged 3.23% modulo and does not exceed 4.5% modulo. When the heat exchanger is divided into 40 segments, the execution time of the calculation programs increases approximately 18 times compared to using the newly developed method, which can be called a significant advantage of the latter. Considering the above, the newly developed method can be widely used for the selection of air coolers, their verification and design calculations.
 BACKGROUND: A universal method for calculating air coolers that is applicable to design and verification calculations is necessary. The method should consider the effect of dehumidification and frosting on the heat exchange process and allow the quick performance of many calculations to simulate the operation of refrigeration and air conditioning systems without significant loss of accuracy. However, this example of calculation method that addresses all the above-mentioned criteria is unavailable in the domestic and foreign literature.
 AIM: This study develops a universal method for calculating air coolers that is applicable to design and verification calculations. This method considers the influence of dehumidification and frosting on the heat exchange process and allows the quick performance of many calculations to simulate the operation of refrigeration and air conditioning systems without significant loss of accuracy.
 MATERIALS: The developed method for calculating air coolers is based on the classical approach of ε-NTU (efficiency– the number of heat transfer units) and is its adaptation, allowing consideration of the influence of dehumidification and frosting on the heat exchange process and performing the calculation (including the combined operating mode of the air cooler) without dividing the heat exchanger into separate segments. The estimation of the error of calculations performed using the developed method was conducted by comparing the calculated values of the thermal power of the device with those using the segmented division method for various operating modes (including combined).
 RESULTS: Comparison with the segmented division method of the heat exchanger showed good convergence of the calculation results with multiple reductions in execution time. The deviation value of the calculated value of the thermal power computed using the developed method from that using the segmented division method averaged 3.23% modulo and did not exceed 4.5% modulo. When the heat exchanger was divided into 40 segments, the execution time of the calculation programs increased approximately 18 times compared to using the developed method, which can be called a significant advantage of the latter.
 CONCLUSION: The division of the heat exchanger into segments for calculation does not result in a significant increase in accuracy compared with the new method. Thus, the developed m-ε-NTU method can be widely used for the selection of air coolers, their verification, and design calculations.

Theoretical and experimental study of the effect of biomass based organic packing wettability on the LDDS and its life cycle analysis

Present study aimed at the fabrication of a counter flow dehumidifier unit using biomass-based organic materials like coconut coir and wood shave as packing alternatives. The wettability of these packings is evaluated by arranging them structurally and their influence on the dehumidification performance has been experimentally studied. A prediction-based mathematical model is constructed to simulate the performance of biomass packing materials. Theoretical and experimental results were very close, with an average deviation of 8.33% for wood shaving and 5.79% for coconut coir packings. Overall, this unit gave the rate of moisture removal (MRR), dehumidification effectiveness (DE), coefficient of mass transfer (MTC) and specific humidity ratio equal to 0.70 g/s, 76%, 37 kg/m2-s and 0.78 respectively. A packing life study and its influence on dehumidification performance is checked. After the third week of continuous usage, results revealed that air contamination CO2, TVOC, and HCHO levels increased by 14.60%, 34.48%, and 38.46%, and the moisture removal rate decreased by 29%, for wood shaving packing. After the third week, the performance deteriorated since the packing fragments became brittle due to the salt interaction. This fibre breakage affected the wettability significantly.

Study on the effect of pressure in humid air dehumidificationournal

In this paper, there are problems such as large energy consumption and complex system in the field of condensation dehumidification. It is found that increasing pressure can strengthen the effect of condensation dehumidification, simplify the system and reduce energy consumption. So this paper simulates the condensation and dehumidification process of humid air in horizontal pipe under positive pressure. The results show that the dehumidification capacity increases by 25%∼30% when the pressure increases by 100kPa on average. The increase of pressure has little effect on the heat transfer coefficient, but the increase of humidity increases the heat transfer coefficient more obvious. When the humidity of wet air increases by 20%, the heat transfer coefficient increases by 18% ∼ 33%. The dehumidification capacity and heat transfer coefficient increase with the increase of pipe diameter and fluid flow rate.

Application of biomass-based wood shaving packing in a liquid desiccant dehumidification system – a source of sustainable energy

ABSTRACT The present work focuses on the construction of a counter flow dehumidification test rig where calcium chloride liquid is used as the desiccant and is made to spray on the novel organic packing made of wood shaving with different densities and porosities. The mass flow rate of the air is varied and the performance parameters such as moisture removal rate (MRR), dehumidification effectiveness, coefficient of performance (COP), sensible heat factor (SHR) and mass transfer coefficient have been investigated. Results demonstrated an increase in the relative humidity, mass transfer coefficient and drop in the COP, MRR and dehumidification efficiency with the increase in the flow airflow rate. On increasing the CaCl2 concentration, dehumidification performance parameters such as MRR, COP and mass transfer coefficient are found to be increased. Out of the three different densities tested, 500 kg/m3 shows best performance with MRR, ΔRH and dehumidification effectiveness being 9.7%, 18.7% and 4.9% lower than the Celdek pad when measured at 5 m/s of air velocity for 30% desiccant concentration. Optimisation of the input parameters has been done and the results revealed that air velocity should be maintained within the range of 4–5 m/s to minimise energy consumption and optimum performance.

Effect of operating parameters of desiccant wheel on the performance of solar desiccant dehumidifier

AbstractTo produce dry air, desiccant wheel is a very common choice now a day. However, it's crucial to utilize the desiccant wheel effectively. Therefore, in the present investigation, a numerical model is developed to identify the best operating conditions for a solar desiccant dehumidifier based on desiccant wheel and it is observed that the dehumidification capacity can be increased by simultaneously increasing the process air velocity and RPH of the desiccant wheel. A higher temperature of hot air for regeneration allows for a higher process‐to‐regeneration sector facial area ratio, which results in higher amount of dry air. After the mathematical investigation, the desiccant wheel is attached with solar air heater for experimental investigation. The solar air heater is based on both ends open evacuated tube collector, which is able to produce hot air at about 150°C at a mass flow rate of 143 kg/h. At this temperature the desiccant wheel shows remarkable dehumidification effectiveness of 0.61 with an average moisture removal of 0.0098 kgwp/kgda. The average thermal effectiveness and DCOP of the solar desiccant dehumidifier are observed to be 0.24 and 0.23, respectively.

Heat efficiency improvement and color evaluation of red chili pepper (Capsicum frutescens) drying with air dehumidification using silica gel

Fresh red chili pepper (Capsicum frutescens) can be dried to a moisture content below 15% for prolonged storage life for a wider range of applications such as in the medicinal, food, and chemical industries. Currently, red chili pepper drying is conducted with direct solar heat that is very dependent on weather conditions. Meanwhile, common convective drying with fossil fuel is inefficient in heat usage and operated at high-temperature air which could potentially lower the product quality. Convective drying with air dehumidification works at low-medium temperatures that are conducive for red chili pepper drying. This research aimed to determine the effect of dehumidification with silica gel on heat efficiency and its impact on the red chili pepper’s quality of color. Drying was conducted at temperatures in the range of 40-70℃ with silica gel as an air dehumidifier. The moisture content and colour of red chili pepper were observed. Results showed that red chili drying with silica gel at a temperature below 60°C can improve the heat efficiency as well as the red chili color retention.

Performance Enhancement of Falling Film Dehumidifier by Variation Number and Width Ratio Rectangular Cylinder Based on CFD Simulation

The implementation of computational fluid dynamics (CFD) technologies has grown popular in various engineering fields to solve problems because it has high efficiency, affordable cost, and requires a relatively short time. This study examines the effect of adding a rectangular cylinder to a falling film dehumidifier with modifications to the geometry of the width ratio and the number of rectangular cylinders. Model without rectangular cylinder variations and three width ratio variations of 0.1D; 0.5D; D with two variations of the number of rectangular cylinders will be simulated under isothermal conditions for the process of mass transfer, distribution of water vapor mass fraction, pressure drop, turbulence intensity, temperature, and dehumidifier performance. The RNG k-ε turbulence model is used to simulate fluid flow with the addition of a user-defined function (UDF). Significant results can be seen in the distribution of water vapor mass fraction in the geometry modification with the addition of a rectangular cylinder with mass transfer enhancement of 12.4 – 13.4% compared to no geometry modification. High Wa,in with variation C is more effective in minimizing the pressure drop of moist airflow. Vortex flow is formed behind the rectangular cylinder, which increases the mass transfer around the flow. The turbulence intensity appears near the liquid desiccant solution and the rectangular cylinder with a value of 33%. The best geometry variation design shows a dehumidification effectiveness value of 36.8%, 3.3 – 3.8% greater than the design without geometry variations.

Experimental investigation of effect of extent and position of bypass openings on performance of a single unit liquid desiccant based indirect evaporative cooler

In high temperature and high humidity zones, evaporative cooling is ineffective and vapour compression systems are less energy efficient. Therefore, an alternative system is highly desirable which is effective, energy efficient and enables the use of cheap and sustainable energy sources. Indirect evaporative cooling helps in retaining humidity level of air, but is less effective in attaining lower air temperatures. To mitigate this challenge, M-cycle indirect evaporative cooling system helps in achieving sub-wet bulb temperatures. In this work, performance of a novel modified indirect evaporative M-cycle cooling system assisted by 40% aqueous Li-Cl liquid desiccant is experimentally investigated against various parameters. The cooling system used in this study is a single unit system which can perform indirect evaporative cooling, liquid desiccant dehumidification and internal cooling to the liquid desiccant. With an air velocity of 1 m/s at the inlet, the introduction of openings in between inlet and exit of the cooling system has shown a maximum improvement of 19.2% in its dew point effectiveness, with unaffected dehumidification effectiveness. Furthermore, it is observed that the dew point effectiveness is decreased with the increasing distance of openings from the inlet. The investigated cooling and dehumidification system is useful as a pre-air-conditioner to conventional air-conditioning systems and also as a stand-alone air-conditioning system.

Performance evaluation of a rotary dehumidifier with molecular sieve desiccant using coupled regeneration mode: Experimental investigation

The increasing demand for energy-efficient and environmentally friendly air conditioning systems has led to the development of innovative technologies such as desiccant cooling systems. This study presents a comprehensive experimental analysis of the dehumidification and thermal performance of a rotary dehumidifier with molecular sieve desiccant designed to effectively remove moisture from the air by utilizing coupled regeneration mode (complete waste heat liberated out of condenser and electric rod heat). Various experiments were conducted to investigate different performance parameters including moisture removed from air by adsorption, moisture added to air by regeneration, dehumidification effectiveness, regeneration effectiveness, moisture removal capacity (MRC), regeneration rate (RR) at different process air inlet temperatures ranging (28–34 °C) and at different regeneration air inlet temperatures ranging (55–62 °C). These experiments were conducted at same air velocity for both adsorption and regeneration segments of rotary solid desiccant wheel using molecular sieve. The results showed that the performance of the desiccant wheel was affected by inlet temperature and humidity ratio for adsorption and regeneration segments. The findings emphasize the system's ability to provide efficient dehumidification and cooling while simultaneously promoting sustainable energy practices. Moreover, the waste heat recovery system significantly contributes to the overall efficiency improvement of the rotary dehumidifier with molecular sieve desiccant, making it an environmentally friendly alternative to conventional air conditioning technologies.

Performance Assessment of Solar Desiccant Air Conditioning System under Multiple Controlled Climatic Zones of Pakistan

Over the past decade, the integration of desiccant technology with evaporative cooling methods has proven to be highly effective and efficient in providing comfortable indoor environments. The performance of desiccant-based direct evaporative cooling (DEC) systems is strongly influenced by environmental conditions, and their output behavior varies across multiple climatic zones. It is not easy to assess the system performance in numerous climatic zones as it is a time-consuming process. The current study focuses on determining the feasibility of a solid desiccant integrated with a direct evaporative cooler (SDI-DEC) for three different climatic zones of Pakistan: Lahore (hot and humid), Islamabad (hot and semi-humid) and Karachi (moderate and humid). To serve this purpose, a specially designed controlled climate chamber with an integrated air handling unit (AHU) was installed to create multiple environmental conditions artificially. It could also provide global climatic conditions under temperature and absolute humidity ranges of 10 °C to 50 °C and 10 g/kg to 20 g/kg, respectively. The weather conditions of the selected cities were artificially generated in the climate chamber. Based on different operating conditions, such as inlet air temperature, humidity and regeneration temperature, the performance of the system was estimated using performance indicators like COP, dehumidification effectiveness, solar fraction and supply air conditions. Results showed that the maximum temperature achieved from solar collectors was about 70 °C from collectors with an area of 9.5 m2. Moreover, the observations showed that when the regeneration temperature was increased from 60 °C to 80 °C, the COP of the system decreased about 41% in a moderate and humid climate, 28% in a hot and semi-humid environment and 23% in a hot and humid climate. The results revealed that an SDI-DEC system has the potential to overcome the humidity and cooling loads of the multiple climatic scenarios of Pakistan.

Techno-economic and emission analysis of solar assisted desiccant dehumidification: An experimental and numerical study

In humid climates, it is challenging to maintain moisture content in the air for human thermal comfort and industrial applications. Commercial dehumidifiers rely on conventional electric heaters to regenerate desiccant material, which accounts for significant energy consumption by such dehumidifiers. As a green solution to this problem, the present study integrates a flat plate solar air collector (FPSAC) with a desiccant dehumidifier to effectively use solar thermal energy and reduce electrical consumption. Performance evaluation of glazed and unglazed FPSAC-assisted desiccant dehumidifier has been conducted at process air flow rates of 33, 51 and 62 m3/h with a constant regeneration flow rate of 42 m3/h. Both glazed and unglazed FPSAC assisted desiccant dehumidification systems had the highest dehumidification effectiveness and percentage increase in temperature at the flow rate of 33 m3/h, while the highest moisture removal capacity was at 51 m3/h. Maximum dehumidification effectiveness, percentage temperature increase, and moisture removal capacity for the glazed case were 0.4, 66.67%, and 6.14 kg/h, respectively. Experimental results showed that the glazed FPSAC-integrated desiccant dehumidification system outperforms unglazed FPSAC in all performance evaluation parameters. Using Transient System Simulation software (TRNSYS), the proposed glazed and unglazed assisted desiccant dehumidification system was modeled and validated with experimental results. Furthermore, a techno-economic analysis of the solar hybrid desiccant dehumidification system has been carried out. The FPSAC used in this study showcased a 33.57% yearly solar fraction with a solar hybrid system having a payback period of 4.23 years. In addition, the hybrid system can reduce greenhouse gas emissions yearly by 0.352 tons of CO2 equivalents.

A simulation study of the effects of membrane structure parameters on dehumidification performance of membrane-based liquid dehumidifier

Membrane-based liquid desiccant air dehumidification has been widely used due to its advantages of pollution-free operation, low energy consumption, and simple module structure. The characteristics of membrane materials play a vital role in the dehumidification performance of membrane modules. Aiming at improving the dehumidification performance and further optimizing membrane modules, this study simulated the wet air dehumidification process in the cross-flow parallel-plate membrane dehumidification module by using FLUENT software and studied the effects of structural parameters (porosity, thickness, and pore size) of the membrane materials on the dehumidification performance of the cross-flow parallel-plate membrane. The results show that with the increase of membrane porosity, pore size and the decrease of membrane thickness, the moisture content at the air outlet of the membrane module decreases, the dehumidification capacity and efficiency increase. Considering the mechanical strength of the membrane material comprehensively, it is concluded that the membrane material with porosity of 0.8, thickness of 0.1 mm, and pore size of 180 nm has the best dehumidification effect for cross-flow parallel-plate membrane dehumidification. This study comprehensively analyzed the structural parameters of dehumidification membrane materials for the first time, which provided a theoretical basis for the design and manufacture of membrane materials with high dehumidification performance.

Research on energy-saving conventional submarine air-conditioning system based on heat and humidity load calculation

The built-in air-conditioning and ventilation system of modern conventional submarines still adopts duct ventilation, which has high working noise, high energy consumption, poor dehumidification effect, and is mainly inter-cooled. For the air quality, hot and humid environment and comfort requirements in the submarine cabin. This project proposes an energy-saving cold storage air-conditioning system suitable for submarines. It adopts the air control method of temperature and humidity independent processing, and combines solution dehumidification and cold storage technology to independently control the temperature and humidity of the cabin, so as to achieve the purpose of efficient dehumidification and energy saving. The system makes full use of the limited space inside the submarine, reduces the energy consumption of refrigeration, improves the underwater endurance and concealment, and provides a healthy and comfortable air environment for the crew of the submarine, which has important strategic value.

Optimization and comparative performance analysis of conventional and desiccant air conditioning systems regenerated by two different modes for hot and humid climates: Experimental investigation

A desiccant air conditioning system is considered a capable alternative to a conventional air conditioning system because of its independent control of temperature, humidity and being eco-friendly. Also, to resolve the problem of more energy consumption for the restoration of a desiccant, structures comprising of desiccant can utilize thermal energy or complete waste heat to revive desiccant material. Therefore, this research work executes an experimental, optimization and comparative examination for conventional and desiccant air conditioning systems regenerated by two different modes, i.e. firstly using (Mode-I) complete waste heat from condenser and secondly using (Mode-II) rod (electric heater) heat for regeneration at different process air inlet temperatures, i.e. (28, 29.5, 31, 32.5, 34, 35.5 and 37 °C), at different process air inlet velocities, i.e. (1.5, 2.5, 3.5 and 4.5 m/s) and a fix (2.5 m/s) regeneration air inlet velocity. Thus, optimization of performance parameters, i.e. VCOP, ECOP, dehumidification effectiveness, moisture removal capacity (kg/hr), DCOP, regeneration effectiveness and regeneration rate (kg/hr), is identified for achieving maximum efficiency of conventional and desiccant air conditioning systems under the above operating conditions.

반려동물을 위한 IoT 기반 이동식 캐리어 디자인과 위치추적장치 개발

As the society developed into a highly industrialized society, familyization of companion animals was promoted, and the basic growth of related industries such as feed, beauty, and pharmaceuticals developed. Recently, wired and wireless communication technology based on sensors, semiconductors, and IoT is also being applied to the location tracking of companion animals that are active outdoors. In particular, various studies are being conducted on theft, accident, location tracking and advance warning of accidents when the blind, disabled, or the elderly are outdoors with companion animals. Therefore, as artificial intelligence (AI) technologies that can comprehensively analyze and determine a large amount of information required between companion animals and humans are applied, so-called ‘pet-tech’ is attracting attention. In monitoring and analysis based on sensor data and momentum, a service centered on the behavior, emotion, and situational awareness of companion animals is provided to consumers, and it is a technology that enables consulting and connection services on the behavior, situation, disease, and abnormal behavior of companion animals. development is gradually increasing. These technical studies related to companion animals lead to the cross-section of animals that accompany humans and become humanized, but on the contrary, it is a case that proves that psychological panic is growing in urbanized human life such as human alienation and loneliness. do. In addition, due to the sharing of space, a product design that can manage cleanliness, hygiene, and health is required, and a planar heating element using nano-carbon is applied as a basic material for antibacterial and odor removal. Nanocarbon is a material that maintains human health, and has been used for a long time because of its excellent life-sustaining power and resilience, such as deodorization, antibacterial action, air purification, early cell activation, pain relief, dehumidification effect, and deep sleep purification. It is also used as a material. In this study, we propose “a mobile carrier and location tracking device based on a planar heating element and IoT for cleanliness, hygiene, and health management where pets and owners coexist”. It tests its performance by supporting a platform that can converge with IoT and track location through product design.

Performance evaluation of PVA/PEO/LiCl composite as coated heat exchangers desiccants

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/CaCl2 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.

Variations of Cooling and Dehumidification Degree Days in Major Climate Zones of China during the Past 57 Years

In previous studies, the concept of degree days has been widely used to indicate heating or cooling energy requirements, but it does not consider the dehumidification effect. In the present study, the concept of dehumidification degree days based on moisture content is used, and the degree days over the past 57 years for temperature decreasing and dehumidification in 4 cities belonging to major climate zones of China are analyzed. The results showed that the number of cooling degree days showed a significant increase (1.2–4.6 days/10 a) in all the selected cities, corresponding to the warming climate. In contrast, the degree days of dehumidification accounted for 19%–45% of the total days in summer and showed significant decreases (2.0–3.7 days/10 a) in the cold, hot summer and cold winter, and hot summer and warm winter climate zones. Comfortable days, i.e., days requiring no cooling and no dehumidification, accounting for 8–45% of the total days in summer, decreased significantly in the extreme cold and cold zones (0.9–1.8 days/10 a) but showed no apparent changes in the hot summer and cold winter and hot summer and warm winter climate zones. This study suggests that energy consumption for cooling increases linearly with climate warming, and only the energy consumed for dehumidification had an apparent decrease. The degree days of dehumidification, as well as those requiring no cooling and no dehumidification, should be fully considered in the capacity design of air-conditioning units, especially air-conditioning systems with temperature- and humidity-independent control (THIC). This study indicates that the assessment of energy consumption for requests for air-conditioning in relation to climate change should be carried out after separating energy consumption for cooling from energy consumption for dehumidification to improve building energy efficiency and indoor comfort.

A Janus-type hygroscopic hydrogel for reusable robust dehumidification and efficient solar thermal desorption

High humidity can lead to hazards such as disruptions in basic human metabolism, machines corrosion, bacteria breeding and so on, which make it an urgent need to develop efficient, reusable, and environmentally friendly dehumidifying materials. Herein, a reusable Janus-type cellulose nanofibrillated based hydrogel (CNH) @ graphene oxide matrix photothermal composite (GMC) hygroscopic hydrogel with porous three-dimensional network and solar thermal surface is manufactured by combining lyophilization and spray coating. The outstanding hygroscopic property of lithium chloride and excellent water storage capacity of biomass-based cellulose nanofibrillated three-dimensional network endow the Janus-type CNH@GMC hygroscopic hydrogel (CGH) with robust air dehumidification performance, while the evenly dispersed GMC with excellent photothermal properties provides the CGH with efficient solar thermal desorption performance. Consequently, the CGH can efficaciously achieve a moisture absorption of 459.3% of its weight and desorption of 82.5% of the absorbed water in static circumstances. More interestingly, a channel with flowing wind is constructed to explore the dynamic dehumidification effect of CGH, finding that the CGH can reduce the relative humidity in the danamic channel from 97.1% to 39.2%. These results mean that CGH can dehumidify air in both static and dynamic circumstances, highlighting its potential for reusable, sustainable, and environmentally friendly dehumidification.

수용액 원심분사 기술이 적용된 액체식 제습 시스템의 제습 및 에너지 성능에 대한 실험적 연구

The main objective of this study was to analyze the dehumidification performance of a centrifugal atomization-based liquid desiccant (LD) dehumidification system and compare energy performance. Dehumidification rate and effectiveness were evaluated to determine dehumidification performance. A parametric study was performed experimentally according to five variables: air temperature, air humidity ratio, solution temperature, solution concentration, and liquid-to-gas ratio. Cooling load was also compared with a packed-bed-based LD dehumidification system via experiment results and simulations. Results indicated that the dehumidification performance was improved at low solution temperature and high solution concentration. The dehumidification rate was also higher in hot and humid air than in a mild air condition. As liquid-to-gas ratio increased, dehumidification effectiveness also increased while dehumidification rate decreased. Finally, the proposed centrifugal atomization-based LD system could achieve the same dehumidification performance at a lower liquid-to-gas ratio than packed-bed-based LD system while saving 72% system cooling load.