Humidity Control Research Articles

Mitigating SSIs: focus on physical operation rooms environmental factors

Background: Surgical site infections (SSIs) are associated with increased morbidity, monetary loss and mortality. The physical aspects of the operation room (OR) including airflow, humidity, pressure, and particulate counts are essential part of SSI prevention. Humidity control is vital to avoid static electricity buildup.Temperature control helps prevent hypothermia. Limiting OR traffic and door opening are essential to prevent airflow disturbance and minimze particles in OR environment. We have recently studied electronic monitoring of OR traffic and the traffic was higher than what was expected. Our aim was to evaluate our real-life measurement of these OR parameters as part of SSI prevention bundle. Methods: This is a prospective study focused on the OR physical environmental factors as part of operative SSI prevention bundle. The study was conducted for 4 weeks at an academic medical center. The study was conducted in two different generations of OR for neurosurgical and ophthalmologic procedures. We performed direct observation of OR traffic as well as environmental parameters (temperature, humidity, pressure, and particulate count) for the entire length of the procedure. We used both directly measured data as well as automated data generated by facilities. Results: The study showed that temperature, humidity, and pressure wer tightly controlled in the OR. This observation was consistent between manual data and automatically generated data. The OR traffic was not easily monitored by the current automatic data and was measured by direct observation. The correlations between particulate count and OR traffic was strongest for 0.3μm (0.7370, and weakest for 1.0μm ( 0.087). The 5.0μm particulate size had a moderate positive correlation of 0.344, Additionally, shorter procedures had less particulate matter in the OR environment. Automated data were only available in the new ORs but could not predict traffic without automated door monitors. But the automated data could easily portray the temperature, humidity and pressure minute by minute. Conclusion: OR traffic increases the particle count particularly the small size. Other physical aspects of the OR environment were tightly controlled. The ability to automatically monitor OR parameters could be extremely helpful for assuring patient safety as well as reviewing OR factors in SSI cases.

Optimizing indoor humidity control with AI: Case study in Abu Dhabi

Optimizing indoor humidity control with AI: Case study in Abu Dhabi

Implementation of the Fuzzy Logic Mamdani Method in the KUB Chicken Egg Incubator

Poultry farming plays an important role in rural Indonesia's economy, with increasing demand for poultry meat and protein-rich eggs. One of the main challenges for farmers is the limited production of chicken seeds and suboptimal egg incubation methods. Modern egg incubators offer a solution with higher ease and efficiency compared to traditional methods. However, existing machines on the market have weaknesses, such as less accurate temperature and humidity control, and less optimal power source switching. The use of fuzzy logic methods in egg incubators has proven to be more efficient than manual methods, with a hatching success rate of 100% for 10 eggs. Fuzzy logic-based egg incubators start hatching earlier and more on days 18 and 19, while manual methods begin on days 19 and 20. The automatic egg-turning process in fuzzy logic machines saves labor and reduces the risk of error. This research highlights the importance of using accurate sensors and optimal temperature and humidity control systems to improve the success rate of chicken egg hatching. Index Terms—poultry farming; egg hatching; temperature; humidity; fuzzy logic

Comparing Temperature and Humidity Control Using PID and Fuzzy Logic in a Climatic Chamber

The presence of a thermohygrometer is important in some places, especially in hospitals and climate room equipment. A climate chamber is an enclosed space or isolated environment, which will provide the environmental conditions of relative humidity and temperature. In accordance with the Decree of the Minister of Health of the Republic of Indonesia. Certain rooms such as rooms in hospitals require special attention to environmental conditions, such as the surgical process that occurs in the operating room. A thermohygrometer is a tool used to monitor room conditions. The thermoygrometer used must be able to trace the measurement results using certain media. A climate chamber is a device that provides the desired climate regardless of the external environment. The purpose of this study was to analyze the comparison of PID and Fuzzy Logic temperature control systems on the Climatic Chamber (Fuzzy Logic System) device which plays a role in the process of measuring room temperature and humidity in the field. The method used in this study was to compare directly with a previously calibrated thermohygrometer. The measurement results at 25°C have a response time of 7 minutes 30 seconds and an overshoot of 0.1°C, at a temperature of 30°C has a response time of 5 minutes 15 seconds and an overshoot of 0.1°C, at a temperature of 35°C has a response time of 5 minutes 30 seconds and 0.2°C overshoot. At 50%RH Humidity has a response time of 13 minutes 30 seconds, at 60%RH Humidity has a 12 minute response time, At 70%RH Humidity has a 6 minute response time. The measurement results show that fuzzy logic control has more advantages than PID control. Fuzzy logic control has a faster response time to setpoint than PID control and fuzzy logic control has smaller overshoot compared to PID control.

On-site evaluation of indoor thermal comfort and energy performance of a liquid-desiccant assisted air-conditioning system in a high-latent-load building

Indoor humidity control is increasingly important because indoor sensible heat ratio decreases to reduce building energy consumption. However, reference vapor compression cooling systems exhibit energy inefficiency and limitations in maintaining indoor thermal comfort. Therefore, this study proposes an alternative heat-pump-driven liquid-desiccant air-conditioning system, independently controlling air temperature and humidity. The reference and proposed systems are applied to a high-latent-load building to investigate their onsite indoor thermal comfort and energy performance empirically and simultaneously under various outdoor summer conditions. The reference system exhibits a thermal comfort satisfaction ratio of 97% only under limited hot and dry weather. Conversely, the thermal comfort satisfaction ratio sharply drops to 2% or less under humid weather. The proposed system consistently achieves a high thermal comfort satisfaction ratio exceeding 90% under various outdoor summer conditions. In empirical comparisons, the proposed system can maintain a thermally comfortable room for an hour while achieving energy savings exceeding 92.4% and 12.1% under warm and humid (rainy season) and hot and humid outdoor conditions, respectively. The proposed system is concluded to consistently maintain indoor thermal comfort while using energy efficiently, demonstrating its widespread applicability for general high-latent-load buildings characterized by low indoor sensible heat ratio values of 0.56 on average.

Effect of water wheel configurations on portable air conditioner performance in high-humidity environments: An experimental study

Nowadays, portable air conditioners (PACs) have gained a broad international market with their advantages of easy installation and flexibility. The water wheel is generally used to solve the drainage problem of the PACs in the high-humidity environment. The reasonable configuration of the water wheel can help extend the continuous operation time and improve the performance of the PACs. This study was built upon existing PACs, exploring the impact of water wheel configurations on the performance of PACs in high-humidity environments. The research revealed that among various water wheel configurations, a dual water wheel configuration functioned better than a single one to help solve drainage problem. And the water wheel configuration that sprays water to the highest temperature area of the condenser proved the most effective for condensate removal. The optimal drainage characteristics of this particular water wheel configuration corresponded to the highest Energy Efficiency Ratio (EER) observed in the PACs, with the maximum increase of 21.11% compared to other water wheel configurations. Additionally, Due to the effect of condensate, with an increase in relative humidity, there was a simultaneous rise in the EER for all water wheel configurations in high-humidity environments.

A view on the performance comparison between adiabatic and internally-cooled dehumidification processes using liquid desiccant

Humidity control is emphasized in various fields. However, the effectiveness comparison between adiabatic dehumidifier (AD) and internally-cooled dehumidifier (ICD) was only conducted in limited cases, without comprehensive understanding of different cooling mediums and working conditions. In this study, the component effectiveness of these two dehumidifiers is parametrically compared. When chilled water serves as cooling medium, AD has sensible effectiveness of 0.65 and latent effectiveness of 0.84 under baseline case, while those of ICD are 0.52 and 0.85 respectively. AD performs better under higher sensible loads, and ICD is more capable of dealing with more moisture transfer. Low water temperature, low air-desiccant ratio and adequately low water-desiccant ratio also highlight the superiority of AD. When secondary air serves as cooling medium, AD always has higher effectiveness than ICD in the studied range, and the superiority is more significant at lower temperature and humidity of secondary air. Sensible effectiveness of 0.44 and latent effectiveness of 0.78 for AD are obtained under baseline case, while those of ICD are 0.07 and 0.74 respectively. ICD has better adaptivity than AD at a circumstance with great variation of operation parameters. The results contribute to enlightening insights for further design of moisture capture components.

Regional and seasonal partitioning of water and temperature controls on urban dryness variability in China

Rapid urban expansion can significantly alter urban microclimate. In recent years, the phenomenon of urban dry islands (UDIs) has attracted increasing attention, but there remains a lack of understanding regarding the impact of urbanization on UDIs in different urban agglomerations (UAs). In this study, vapor pressure deficit (VPD) was used as the humidity indicator, and meteorological data from 20 UAs were used to explore how atmospheric temperature and humidity control urban dryness variability in China. Our analysis revealed that VPD trends are increasing with a median rate of 0.121 hPa/decade and 0.103 hPa/decade for urban and rural areas, respectively. The urbanization effect is more significant in coastal UAs. Furthermore, the difference in VPD between urban and rural areas obviously varied on a seasonal scale, with the largest difference observed in summer (i.e., −0.63 hPa on average and up to 2.66 hPa). Notably, our findings suggest that changes in local atmospheric water content primarily control the response of VPD to urbanization. In summer, the average contribution of temperature is 0.118 hPa, while the average contribution of relative humidity is 0.723 hPa. Overall, these results have important implications for our understanding of the impacts of urbanization on local climate.

Revolutionizing onion preservation: A novel aerated storage approach

The second goal of sustainable development is ending hunger, achieving food security improving nutrition, and promoting sustainable agriculture. Improved storage system is a part of sustainable agriculture. This research aimed to design and develop an aerated storage system for onions and examined the extent of losses to assess the efficacy of the storage system. Unseasonal rainfall and adequate storage facilities result in quick sales and spoilage of onions. A huge amount of onion is damaged due to a lack of proper post-harvest actions like storage, transportation, temperature control, and humidity control in our country. In this study, 40 kg of onion inside the storage and 10 kilograms outside the storage were stored for four weeks from 12 October to 8 November to observe parameters like percentage of moisture loss, sprouting, deterioration, and marketable onion. Temperature as well as relative humidity was observed throughout storage. After completing the research, it was found that the appropriate temperature was 27˚C with 83% relative humidity resulting in minimum losses throughout four weeks of storage period. It was also observed that marketable onion bulbs for aerated storage systems was 97.536% on the other hand marketable onion bulbs for natural or open storage systems was 91.629% which was less than aerated storage systems. So, the aerated storage system is more effective for storing the onion than the natural or open storage system. Small-scale farmers will be benefited and the supply chain management will be maintained using this storage system. Additionally, stakeholders and families will benefit from reduced onion damage percentages when utilizing this storage solution.

Application of ZigBee Technology in Smart Soil Temperature and Humidity Control Systems

As global food security increasingly becomes a focus, challenges faced by Chinese agriculture are particularly prominent. This study introduces an intelligent monitoring and control system for soil temperature and humidity using ZigBee technology, aimed at enhancing agricultural production efficiency and crop yield. The system's core, equipped with an STC89C52 microcontroller and DHT11 temperature and humidity sensors, gathers data and wirelessly transmits it to a central control unit via ZigBee modules, which then automatically adjusts the agricultural production environment to ensure crops grow in the most ideal soil temperature and humidity conditions. Compared to traditional methods, this system achieves remote monitoring and precise control, providing an innovative solution for modern agricultural production. Experiments prove that the system not only improves control accuracy but also significantly enhances operational convenience and response speed, playing an important role in promoting the development of smart agriculture.

Humidity and temperature nonlinear control based on almost disturbance decoupling and state observers for air-handling units

The almost disturbance decoupling problem for air-handling units (AHUs) containing unmeasurable states is addressed. Firstly, a state observer is introduced to estimate the supply air temperature, which is an unmeasurable state. Secondly, the almost disturbance decoupling technique is utilized to attenuate the influence of unknown disturbances including outdoor temperature, outdoor humidity ratio, heat load, and strength of the humidity source. Finally, compared with the linearization and PID control methods, simulation results verify the superiority and effectiveness of the proposed controller.

Methylammonium‐Free Ink for Low‐Temperature Crystallization of α‐FAPbI3 Perovskite

AbstractFormamidinium lead triiodide (FAPbI3) perovskite without methylammonium and/or Cs cations is considered the most promising candidate for perovskite photovoltaics. However, the crystallization of photoactive α‐FAPbI3 requires high‐temperature annealing (≥150 °C) and a controlled humidity environment when methylammonium‐containing additives are absent. A methylammonium‐free ink is reported that enables low‐temperature (≤80 °C) crystallization of photoactive α‐FAPbI3 films, while also demonstrating compatibility with blade‐coating large‐area films in ambient air. The synergistical effects of methylphenyl sulfoxide and PbCl2 facilitate the formation of an intermediate phase of nanoscale‐disordered δ‐FAPbI3, which dramatically reduces the crystallization temperature of α‐FAPbI3 down to 80 °C and even below. The 80 °C crystalized α‐FAPbI3 exhibits reduced strain and improved uniformity compared to high‐temperature annealed counterparts. The synthesized ink and the corresponding intermediate precursor film are also found remarkably stable, allowing open‐air processing without the need for humidity control. Highly efficient n–i–p structured α‐FAPbI3 minimodules can be fabricated under an ambient environment RH 50% with the ink at 80 °C, achieving a power conversion efficiency of up to 22.4%. The discovery of the low‐temperature FAPbI3 ink paves a new avenue for printing perovskite solar cells and associated optoelectronic applications, accelerating the commercialization progress of perovskite materials.

Novel MOF-based autonomous humidity control materials for energy-efficient indoor moisture regulation

The concept of autonomous humidity control material (AHCM) is inspired by phase change material. AHCM is a new type of functional sorbent material. It can adsorb/release sufficient water vapor at the target relative humidity level and autonomously maintain the indoor relative humidity at a set value/range without external intervention, which cannot be achieved by conventional sorbents (e.g., zeolite, silica gel, etc.). In this study, a novel metal-organic framework (MOF) based AHCM is prepared, and its application for energy-efficient indoor moisture control has been investigated. The new MOF-AHCM has an S-shaped water vapor isotherm, large porosity, and high moisture adsorption capacity. The trigger points for adsorption and desorption occur at 60 % and 40 % RH, respectively. It means MOF-AHCM can autonomously regulate the indoor relative humidity to fall within 40%–60 % RH, which fits the thermal comfort range recommended by ASHRAE well. The physicochemical and hygrothermal characteristics of the synthesized MOF-ACHM have been assessed. Full-scale chamber tests were carried out to verify the humidity control ability of the new material. The experimental results show that MOF-AHCM can significantly mitigate indoor humidity fluctuation and regulate the humidity level within the target range autonomously. Furthermore, numerical simulation has been performed to investigate the impact of MOF-AHCM on building energy consumption in different moisture regions globally, namely, arid, semiarid, dry, moist, and wet areas. The results reveal that MOF-AHCM has an excellent humidity control capacity and can reduce the latent cooling demand of HVAC systems in most climates, especially in arid, semiarid, dry, and moist areas.

Stable nature of [BH4]− ions in deliquescence thin-film NaBH4 and humidity control of their decomposition toward hydrogen supply and storage application

In this study, we investigated the deliquescence of NaBH4 thin films under atmospheric conditions toward their hydrogen supply application. Upon exposed to air, the film deliquesced along with generating hydrogen due to the decomposition of [BH4]- ions, but the decomposition rate was slow enough for a sizable amount of [BH4]- ions remained stable in the deliquesced film. As a result, a reversible deliquescence-recrystallization cycle in the NaBH4 thin film could be achieved through control of humidity. Molecular dynamics simulations suggested that Na+ and [BH4]- ions tended to neighbor each other with almost the same intra-distance as that in the crystal. A kind of such local ordered structures in deliquesced NaBH4 may prevent an excess hydration and subsequent decomposition of [BH4]- ions and is responsible for the stability of [BH4]- ions, enabling the reversible deliquescence-recrystallization cycle. These combined experimental and theoretical insights offer new perspectives on controlling hydrogen release from borohydrides based on humidity conditions in the thin film form.

Flow-through moisture meter for measuring grain moisture as part of an automated grain moisture control system

The methods of increasing the accuracy and efficiency of the production process, as well as ensuring high quality of final products in the grain processing industry, are investigated. It is shown that to solve the problem of insufficient quality control of grain materials, an automated system for monitoring the properties and characteristics of bulk granular materials is necessary. The features of the construction of automatic and automated systems for monitoring the properties and characteristics of bulk granular materials are considered. Measurement methods and control devices of the main technological parameters used in the management of grain processing facilities are briefly described. It is proposed to include a flow moisture meter in the automated grain moisture control system. The physical properties of grain and grain materials, measurement conditions and instrumentation for grain moisture control are analyzed. The use of devices based on the dielkometric method in the subsystem of an automated process control system is discussed. The application of intelligent sensors of a measuring system with a complex multilevel hierarchy is described. The structure of the interconnection of measuring devices for intellectual support of humidification processes and quality control of the studied materials is given. A functional diagram and metrological characteristics of a prototype grain moisture monitoring device, a flow moisture meter, are presented. The metrological characteristics of this device meet the requirements of the grain processing industry and allow it to be used as part of a humidity control system

Smart Monitoring System Pada Pembudidayaan Jamur Tiram Menggunakan Metode Fuzzy Logic

Mushrooms, which are known as food commodities, when cultivated require temperatures between 22-28°C and humidity of 60-80%. Controlling these two factors is very crucial, especially when weather fluctuations occur throughout the day. As a solution, an artificial intelligence-based system was introduced to regulate temperature and humidity. The "fuzzy control" technique in artificial intelligence is an option because of its flexibility and convenience without involving complex mathematical calculations. The Fuzzy Mamdani method is one approach to "fuzzy control" which allows automatic control of temperature and humidity in mushroom cultivation areas. To apply this method, sensors are needed that can provide data to the fuzzy system. This fuzzy system works in four steps: fuzzification, rule determination, inference, and defuzzification. Based on the results of comparative tests with MATLAB software, there is a correctness level of around 26% in the measurement results.

Effectiveness of the Fuzzy Logic Control to Manage the Microclimate Inside a Smart Insulated Greenhouse

Agricultural greenhouses incorporate intricate systems to regulate the internal climate. Among the crucial climatic variables, indoor temperature and humidity take precedence in establishing an optimal environment for plant production and growth. The present research emphasizes the efficacy of employing intelligent control systems in the automation of the indoor climate for smart insulated greenhouses (SIGs), utilizing a fuzzy logic controller (FLC). This paper proposes the use of an FLC to reduce the energy consumption of a greenhouse. In the first step, a thermodynamic model is presented and experimentally validated based on thermal heat exchanges between the indoor and outdoor climatic variables. The outcomes show the effectiveness of the proposed model in controlling indoor air temperature and relative humidity with a low error percentage. Secondly, several fuzzy logic control models have been developed to regulate the indoor temperature and humidity for cold and hot periods. The results show the good performance of the proposed FLC model as highlighted by the statistical analysis. In fact, the root mean squared error (RMSE) is very small and equal to 0.69% for temperature and 0.23% for humidity, whereas the efficiency factor (EF) of the fuzzy logic control is equal to 99.35% for temperature control and 99.86% for humidity control.

Fuzzy‐PID controller based on improved LFPSO for temperature and humidity control in a CA ripening system

AbstractTemperature and humidity as the key factors affecting the storage and ripening of fruits and vegetables directly determine the quality of fruits and vegetables. In this paper, a temperature and humidity model was constructed based on an integrated device of controlled atmosphere storage and ripening. Aiming at the shortcomings of the temperature and humidity model such as large inertia, nonlinearity, and model uncertainty, a fuzzy‐PID controller based on the improved Lévy flight particle swarm algorithm (LFPSO) is proposed. Initially, a mathematical model of temperature and humidity is developed through mechanism research and parameter estimation. Subsequently, a temperature and humidity fuzzy‐PID control strategy is proposed for regulating temperature and humidity. An improved LFPSO is then introduced to optimize the key parameters of the fuzzy‐PID controller, such as the quantization factor and the scale factor. The superiority of the improved LFPSO algorithm is verified by comparing the test functions. Finally, the improved LFPSO‐fuzzy‐PID controller, fuzzy‐PID controller, and Smith‐PID controller are applied to the simulation model for comparison using the MATLAB Simulink simulation platform. The results show that the improved LFPSO‐fuzzy‐PID control algorithm has a good control effect in the temperature and humidity simulation system of controlled atmosphere (CA) ripening container, which provides a reference for solving the optimization problem of actual engineering design.Practical applicationsIn order to reduce the postharvest cold chain losses of fruits and vegetables, this paper proposes a containerized style device that combines fruits and vegetables storage and ripening for simplifying the losses caused by transshipment at cold chain nodes. Since temperature and humidity play a key role in fruits and vegetables storage and ripening, which directly affect the product quality, this paper establishes a complete mathematical model of CA ripening temperature and humidity system by combining mechanism modeling and parameter identification. In order to keep the temperature and humidity within the ideal range, Smith‐PID controller, fuzzy‐PID controller, and fuzzy‐PID control method based on improved Lévy flight particle swarm optimization are proposed to regulate the air conditioner and humidifier. The performance of three different types of controllers was tested on the MATLAB. The simulation results demonstrate that the improved LFPSO‐fuzzy‐PID controller is superior and more effective than Smith‐PID and fuzzy‐PID controllers.

Investigations on an integrated air-conditioning system using technologies of desiccant dehumidification, indirect evaporative cooling and CO2 capture

The advance of air-conditioning systems has become a popular topic, due to its huge energy consumption and the increasing demand of improving indoor air quality. Although various approaches have been proposed for humidity, temperature and CO2 control, their coordination has not yet been studied. In this study, the technologies of desiccant dehumidification, indirect evaporative cooling and direct CO2 capture are innovatively integrated in an air-conditioning system, by which their respective advantages can be exerted and limitations can be compensated. Under a base working condition with ambient temperature of 35 °C and relative humidity of 80%, the overall coefficient of performance of the integrated system reaches 0.93, with an improvement of 53.3% against a conventional scheme. The integrated system is more efficient at higher crowdedness. With occupant number from 2 to 22 in a room, the advantage of the integrated system ranges from 50.7% to 85.6%. Parametric studies on different indoor and outdoor conditions are conducted, indicating that the energy efficiency advantage is more outstanding at higher indoor temperature, lower ambient temperature and lower ambient humidity. The factors of economic, environment and health are discussed, where the integrated system exhibits superiority against conventional systems and existing studies as well. Approaches are raised to improve the performance and promote future studies. The results in this paper contribute to providing a scheme for the integration of different technologies and enlightening insights for the advance of air-conditioning systems for the sake of air quality improvement, energy saving and emission reduction.

Heat and mass transfer analysis of desiccant-coated heat exchanger with desiccants and metal-organic framework for bus air conditioning applications

Desiccant-coated heat exchangers (DCHEs) in air conditioning offer advantages like independent temperature and humidity control, reduced energy consumption, and high performance. However, the availability of desiccants with high water adsorption and low thermal energy requirements is limited. The present study proposes that aluminum fumarate (Al-Fum) MOF-coated heat exchangers will outperform conventional desiccants, especially at low regeneration temperatures (around 50°C). In order to evaluate this hypothesis, the performance of DCHEs was evaluated with a validated analytical model for different solid desiccant coatings: silica gel, zeolite, and Al-Fum MOF. Water vapor sorption characteristics, heat and mass transfer, and adsorption and desorption capacities were determined. The results showed that the Al-Fum MOF-coated heat exchanger outperformed silica gel and zeolite at low regeneration temperatures under adiabatic conditions. The MOF exhibited superior water uptake capacity (0.39 g/g) between 20% and 80% RH compared to the other studied conventional desiccants. Moreover, the MOF achieved the lowest outlet air temperature. At 19.5 g/kgda, the MOF demonstrated higher adsorption rates (4 % and 0.3 %) than zeolite and silica gel. These findings highlight the potential of Al-Fum MOFs as energy-efficient solutions for controlling indoor air humidity, particularly for latent-sensible heat separation systems with conventional vapor compression bus air-conditioning systems.