Humidity Control System Research Articles

Potential utilization of guar straw and wood wool in controlling relative humidity and temperature of storage environment

AbstractIn this study, guar straw and wood wool were used for the development of a relative humidity (RH) and temperature control system based on the storage requirement of onions in a semi‐arid region. The RH and temperature control system includes two major units: (a) dehumidification—three compartments of guar straw balls/guar balls and (b) humidification—water‐saturated wood wool pad (evaporative cooling). Guar balls of ~25 mm diameter were made by mixing 40% straw powder, 59.5% water, and 0.5% guar gum (wt/wt). The balls were dried until 5.6% moisture level before using in dehumidification unit and analyzed for thermal properties. The RH and temperature control system was evaluated for its ability to maintain the requisite RH inside the onion storage structure. The dehumidification unit can reduce the RH by 4.9% and the humidification unit can increase the RH by 4.2% in the storage chamber. Further, the humidification unit has a cooling efficiency of 83.3%. The control system was efficient in maintaining the necessary storage RH in a range of 60–70% with a variation of 1.5%, and 22–37°C storage temperature. Therefore, the storability of the onions in the conditioned environment was close to five months compared to three and a half months in control/ambient condition. Overall, the novel guar straw balls showed the desiccant properties that can be used with water‐saturated wood wool for controlling RH and temperature of a storage environment.Practical ApplicationsAgricultural waste generally remains unutilized that create disposal and environmental challenges. Hence, the task of agricultural waste management is paramount. For farm and industrial applications, the development of low‐cost desiccants and systems for controlling conditioned atmosphere using agricultural waste is interesting. In the present study, a relative humidity (RH) and temperature control system was developed using guar straw and wood wool. The control system is proved to be efficient in maintaining the storage requirement of onions; thus, extended the storage life significantly. This environmental‐friendly system can be used, in storage, preservation and drying of food products.

Design of temperature humidity and illumination control system for indoor flowers

In order to improve the automation of indoor flower environment monitoring, enable the flowers grow in the best environment, this paper designs an automatic control system of temperature, humidity and illumination based on STC89C52 single chip microcomputer. Temperature sensor DS18B20 is applied to sense indoor air temperature, meantime, YL-69 soil moisture sensor and photosensitive resistance are used to sense soil relative humidity and light intensity respectively. Temperature, humidity and light intensity are transmitted to single chip microcomputer for analysis and processing, and the results are displayed by OLED display module. The upper and lower limits of environmental parameters are manually preset through the keyboard. When the temperature and light intensity exceed the upper limit, the system can send out alarm signals and output control signals to drive the corresponding actuator to work; when the soil moisture is lower than the lower limit, the system will automatically alarm and water automatically; when the humidity reaches the upper limit, watering will be stopped to ensure the indoor environmental parameters in the best value suitable for flower growth. The system has been tested and debugged. The results show that the control system can effectively process and display the flower environment information, achieving the purpose of automatically adjusting and controlling the temperature, humidity and illumination of flowers, has strong promotion value.

Gas-flow humidity control system for neutron reflectivity measurements.

We developed a novel humidity control system for neutron reflectivity measurements based on the two-way gas-flow method that can generate up to 85% relative humidity (RH) within a temperature range of 5 °C-85 °C. The system consists of a gas-flow-type humidity generator and a thermostatic sample chamber, each of which can independently control the temperature. The key features include rapid humidity response and long stable operation time. The humidity reaches equilibrium within 2 to 5 min during the humidity change, and the system exhibited acceptable stability over a three-day, nonstop experimental measurement duration, with a precision of ±1% RH at 85 °C and 85% RH. The sample chamber is capable of measuring substrate samples with dimensions of up to 2-in. in diameter and 5-mm in thickness. We demonstrate the reflectivity data measured at a pulsed neutron facility, MLF BL17, in the Japan Proton Accelerator Research Complex. The combined use of this system with neutrons permits in situ, time-resolved studies of the swelling process of polyvinyl alcohol and adhesive materials.

Camfil works with CTT Systems to improve aircraft air quality

Camfil has announced a Memorandum of Understanding (MOU) with Swedish aircraft humidity control systems manufacturer CTT Systems AB, to incorporate ozone and VOC filtration in aircraft humidifiers.

Research on temperature and humidity decoupling control of clean air conditioning system

In the clean air conditioning system, in order to ensure that the temperature and humidity in the room are within the allowable accuracy range, it is necessary to control the dew point temperature. However, due to the inconsistency of the temperature and humidity control systems, the delay and inertia time constant of each channel are very different, so the dew point temperature is difficult to control. In order to achieve accurate control, multiple valves are opened at the same time in the system, which leads to energy loss, and usually a single circuit works normally. But when multiple chains work at the same time, the system is not easy to be stable. Therefore, in order to ensure the long-term safe operation of multi-parameter control system, making full use of mature technology and single variable control experience is an effective method to manage multi-parameter system.

Simulasi Sistem Kendali PID Lingkungan Kelembaban Tanaman Hortikultura pada Green House untuk Inovasi Pangan Lokal

The research is aims to create a humidity control system simulation horticultural palnts in the greenhouse. The controls used are PI and PID. This control system is simulated using the Simulink Matlab software. The constant values of P, I, and D are obtained using Matlab's application, namely PID Tuner. PI control uses a proportional constant value of 3.7174 and an integral of 0.12173. Meanwhile, PID control uses a proportional constant value of 0.61842, an integral of 0.05412, and a derivative of 0.15797. PI control system response time analysis has a rise time of 0.769 seconds, a settling time of 8.7 seconds, and an overshoot of 1.57%. Meanwhile, the response time for the PID control system has a rise time of 6.51 seconds, a settling time of 11.3 seconds, and an overshoot time of 0.103%. The PI control system has the fastest response time up and setting time but has a greater overshoot compared to the PID control system.

A Filament Supply System Capable of Remote Monitoring and Automatic Humidity Control for 3D Printer

In this paper, we suggest an edge computing system for 3D printers that can monitor and control the relative humidity inside the filament supply. To this end, we studied changes in the stress-strain curve from a 3D-printed object owing to the humidity-sensitive characteristics of the polylactic acid (PLA) filament. The filament supply system is equipped with a relative humidity and temperature sensor and a photo interrupter in order to obtain data; a server is implemented using a Raspberry Pi to remotely monitor the temperature and humidity inside the filament supply and to monitor its state. In addition, a humidity control system (manufactured using a Peltier module) allows users to remotely control the humidity level inside the supply system. In conclusion, an integrated monitoring system was constructed with a filament supply system and the abovementioned functions, and was then integrated into an existing 3D printer monitoring system. This monitoring system can be used to constitute a stable environment for research on 3D printers.

Water retention capabilities of collagen, gelatin and peptide as studied by IR/QCM/RH system.

In this study, water retention properties of triple helix collagen, gelatin (separated single chains) and peptide (broken peptide fragments) were studied by using IR micro-spectroscopy equipped with a relative humidity (RH) control system and quartz crystal microbalance (QCM). Adsorbed water ratios (wt%) are found to be in the order of collagen, gelatin and peptide (at about RH=60%, 22wt% for collagen, 14wt% for gelatin and 9wt% for peptide). Free water molecules with longer H bonds are the major adsorbed water species for collagen, gelatin and peptide. IR band shifts and changes in normalized band areas of functional groups are generally larger for collagen than gelatin and peptide, indicating larger interactions of water molecules with functional groups such as aliphatic CH2, CH3, amides, COO- and C-O for collagen. Relations between normalized band areas show that water molecules are interacting with aliphatic CH species and C-O bonds of collagen. Since the fibril structures of collagen triple helices are reported to be cross-linked by sugars, water molecules can be attracted to polar C-O bonds of sugars linking collagen triple helices in fibrils and they are interacting with adjacent aliphatic CH side chains on the surface of fibrils.

Membrane module design, constructions, and testing for vacuum sweep dehumidification (VSD): Part II, prototype performance vs variations in feed conditions

The lack of membrane humidity control systems for air conditioning (AC) systems is due, in part, to the lack of optimized/tested application specific membrane modules. Part I developed an AC membrane module that differed from typical membrane modules. Part II measures the developed module's performance using three different humid feeds representing three applications: 5 g/kg-DA producing dry air (<0 °C dew pt.) for industrial uses, humid residential air (11 g/kg-DA) and outside air on a hot/humid day (17 g/kg-DA). Performance measured vs changes in feed velocity, sweep/feed ratio, and feed humidity. The effective overall module water permeance, Ko, increased with increasing sweep/feed ratio, feed velocity and absolute humidity. The dynamic response of the VSD system being cycled on/off is near instantaneous without evidence of humidity spiking above the feed humidity during the transition to an off condition. The Joule-Thompson cooling of the retentate from the decompressed sweep stream is detectable but negligible for the proposed application (<0.05 °C). The scaled-up module designed for treatment of 8.5 m3/min of humid residential air or 4.25 m3/min of hot/humid air has 20 m2 of membrane area contained in a rectangular feed to retentate chamber of 0.61 m × 0.23 m x 0.61 m.

Sorption cable sensor with large sensing range and fields of its application

The paper discusses the existing approaches to the use of point and cable sensors to control leaks and humidity. The principal disadvantages of monitoring systems based on them are shown: when detecting leaks, there is a delay in the response time due to the condition of fluid accumulation around the sensors; when controlling the humidity of extended environments, it becomes necessary to install a large number of point sensors with individual switching channels; there is no universal sensor for monitoring leaks and humidity. An alternative solution is proposed - a sorption cable sensor with a large sensitivity range, which, as a leak detector, can be placed anywhere in 3D space where leakage is most likely, and as a linear humidity sensor, it can replace point sensors in an extended control zone. The research results of the developed cable sensors confirm their high sensitivity, speed and relaxation ability to recover (dry) after leaking. The areas of application considered in the article, examples of the implementation of a sorption cable sensor in a system for monitoring leaks and air humidity of computing nodes with liquid cooling of Russian supercomputers testify to the high efficiency and development potential. Based on sorption cable sensors, it is possible to build effective systems for early detection of leaks by the first signs of their manifestation, environmental humidity control systems and universal leakage control systems, steam breakthroughs and the level of relative humidity. Reducing the time for detecting leaks and steam breakthroughs will allow taking preventive measures to prevent the development of damage, and the use of cable humidity sensors instead of distributed point sensors will dramatically reduce the cost of organizing humidity monitoring of extended environments.

Design of Temperature and Humidity Control Systems in Quail Puppies Cages Using Fuzzy Logic Method

After the quail eggs hatch, quail chicks need a warm place as a substitute for the mother to maintain body temperature. The temperature needed by quail chicks is approximately 37°C in the first week and each following week the temperature is lowered to room temperature of 28°C. This research applies the control of temperature and humidity of quail chicks based on fuzzy logic Tsukamoto method. As a detector of temperature and humidity on drums used DHT11 sensor. This temperature and room control system is designed to reduce mortality in quail chicks. The average temperature and humidity reading error for quail puppages by using the DHT 11 sensor is 1% of the temperature reading and 2% of the humidity reading. The results of the implementation of fuzzy logic control are able to maintain the stability of temperature and humidity in quail chicks cages at 32°C – 38°C with humidity between 40% RH – 70% RH.

Effect of humidity on tribological properties and electrification performance of sliding-mode triboelectric nanogenerator

For vertical contact-separation-mode triboelectric nanogenerator (TENG), the hydrophobic surface is often used to improve the electrical output under high humidity condition. However, for sliding-mode TENG, the triboelectric effect is accompanied with the friction and wear of material, and whether the hydrophobic surface is beneficial to the durability as well as the stability of electrical output has been really ambiguous. In the paper, the pillar arrays with different pitches are fabricated through lithography, deep reactive ion etching and replication techniques to get the hydrophobic surface with different static contact angle. Based on the test platform with humidity control system, the effects of pillar pitch and normal force on the coefficient of friction, mass loss, and open-circuit voltage are investigated experimentally at different relative humidity condition. The results show that the effect of humidity on electrical output for sliding-mode TENG is different from that for vertical contact-separation-mode TENG. For a certain patterned surface of sliding-mode TENG, the coefficient of friction, short-circuit current and open-circuit voltage increase with the increasing relative humidity at first and diminish afterwards. The maximum values of them are achieved at 50% relative humidity. The mass loss diminishes with the increment of relative humidity. For surfaces with different pillar pitch, the coefficient of friction and open-circuit voltage decrease with the increasing pillar pitch, while the mass loss increases. Moreover, the decrease in pillar pitch, in which the contact angle of surface is increased, can improve the durability as well as the stability of output of sliding-mode TENG. In addition, although the greater normal force can enhance the stability of open-circuit voltage for sliding-mode TENG under humidity condition, the contact angle of surface will be reduced more obviously in the process of wear, speeding up the failure of hydrophobic surface. This study reveals the effect of hydrophobic surface on the durability as well as the stability of output for sliding-mode TENG and provides reference for texture design at different humidity conditions.

A Low-Cost Humidity Control System to Protect Microscopes in a Tropical Climate.

Introduction:A clean and functional microscope is necessary for accurate diagnosis of infectious diseases. In tropical climates, high humidity levels and improper storage conditions allow for the accumulation of debris and fungus on the optical components of diagnostic equipment, such as microscopes.Objective:Our objective was to develop and implement a low-cost, sustainable, easy to manage, low-maintenance, passive humidity control chamber to both reduce debris accumulation and microbial growth onto the optical components of microscopes.Methods:Constructed from easily-sourced and locally available materials, the cost of each humidity control chamber is approximately $2.35 USD. Relative humidity levels were recorded every 30 minutes over a period of 10 weeks from two chambers deployed at the Belize Vector and Ecology Center and the University of Belize.Results:The humidity control chamber deployed at the University of Belize maintained internal relative humidity at an average of 35.3% (SD = 4.2%) over 10 weeks, while the average external relative humidity was 86.4% (SD = 12.4%). The humidity control chamber deployed at the Belize Vector and Ecology Center effectively maintained internal relative humidity to an average of 54.5% (SD = 9.4%) over 10 weeks, while the average external relative humidity was 86.9% (SD = 12.9%).Conclusions:Control of relative humidity is paramount for the sustainability of medical equipment in tropical climates. The humidity control chambers reduced relative humidity to levels that were not conducive for fungal growth while reducing microscope contamination from external sources. This will likely extend the service life of the microscopes while taking advantage of low-cost, locally sourced components.

Perancangan Sistem Notifikasi Serta Kendali Suhu dan Kelembapan Menggunakan Aplikasi BLYNK Untuk Budidaya Jamur Tiram

Urban farming (gardening in the middle of the city) is increasingly in demand by modern society. Urban farming provides business opportunities as well as being a lifestyle trend. One of the plants that can be cultivated at home is oyster mushroom. Oyster mushroom cultivation is quite easy but requires a special environment to grow up. To do mushroom cultivation at home, it is necessary to manage temperature and humidity to achieve optimal temperature and humidity. A temperature and humidity control system that can be monitored and controlled through the smartphone is the result of the study. Temperature and humidity detected by the DHT22 sensor, then read by NodeMCU and sent to the Blynk application via a WiFi connection are considered as the input system. WiFi used by NodeMCU is the same as WiFi used by smartphone s. Blynk on a smartphone will display the temperature and humidity read by NodeMCU. If the temperature and humidity are out of the optimal temperature and humidity range for oyster mushrooms, a notification will appear on the smartphone . Temperature and humidity control can be done by pressing the ON / OFF button on Blynk to turn on and turn off the lights or the fan as needed, so that the temperature and humidity return to optimal. Based on testing, the system successfully displays temperature and humidity on a smartphone , displays notifications and makes control. The relative error of the temperature measurement is 2.6% and the relative error of the humidity measurement is 3.2%.

Research on Temperature and Humidity Decoupling Control of Constant Temperature and Humidity Test Chamber

The temperature and humidity system is a system commonly used in industry and is recognized as one of the most complex systems. Temperature and humidity are important parameters for improving production quality in industrial production. To carry out effective control, factors such as nonlinearity, large hysteresis and real-time change must be considered, and there is mutual coupling between temperature and humidity. Temperature change will lead to humidity. The change of humidity and the same change of temperature will also affect the temperature change. The positional PID control can achieve satisfactory results. In this paper, through the analysis of the temperature and humidity system model, the feedforward decoupling compensation method is adopted for the characteristics of the temperature and humidity control system, which provides an effective way for the modeling and control of the temperature and humidity system. The simulation results show that the feedforward decoupling controller designed in this paper can achieve satisfactory results under various experimental conditions.

Water vapor adsorption on poly(N-isopropylacrylamide) gel cross-linked with N, N′-methylenebisacrylamide

Water vapor adsorption characteristics and the thermosensitivity for vapor adsorption of poly(N-isopropylacrylamide) gel (NIPA gel) cross-linked with N, N′-methylenebisacrylamide (MBAA) (cross-linked NIPA gel) were investigated for application in desiccant humidity control systems. The cross-linked NIPA gels were prepared via copolymerization of NIPA monomers and MBAA monomers, which were used as crosslinkers, at various reagent concentrations and polymerization temperatures in the range of 283–323 K. The water vapor adsorption isotherms of NIPA homopolymer, MBAA homopolymer, and cross-linked NIPA gels were obtained at adsorption temperatures in the range of 298–323 K using a volumetric gas adsorption apparatus. The water vapor adsorptivity of the cross-linked NIPA gel increased with increasing MBAA monomer concentration and decreasing NIPA monomer concentration. NIPA homopolymer under dry conditions showed weak thermosensitivity for water vapor adsorption between 298 and 313 K. Meanwhile, MBAA homopolymer showed almost no change in water vapor adsorptivity above adsorption temperatures of 298 K. The cross-linked NIPA gels had a similar thermosensitivity to NIPA homopolymer, but its sensitivity might be shifted to higher temperature than NIPA homopolymer. Thermosensitivity of the cross-linked NIPA gel was effective in improving polymer water adsorptivity, necessary for desiccant humidity control systems; however, the adsorption performance of the polymer gel systems investigated require further improvements before practical application will be possible.

Changes in IR band areas and band shifts during water adsorption to lecithin and ceramide.

Adsorption of water to a phospholipid (lecithin) and a ceramide were studied by IR microspectroscopy equipped with a humidity control system and quartz crystal microbalance (QCM). The water weight ratios increase up to 12.2 wt% for lecithin and 1.2 wt% for ceramide at RH ~80%, with linear correlations with infrared OH (+NH) band areas. For lecithin, the 1230 cm-1 band (PO2-) and the 1735 cm-1 band (CO) shift to lower wavenumbers, while the 1060 cm-1 band (PO2-, POC) shift to higher wavenumber with RH. Band areas of phosphates (1230 and 1060 cm-1) increase with RH showing positive relations with the band area of bound water. Bound water molecules with shorter H bonds might be bound to these phosphate groups. Band areas of aliphatic CHs are negatively correlated with the increasing adsorption of free water. Free water molecules with longer H bonds might interact loosely with aliphatic chains of lecithin. For ceramide, only the 1045 cm-1 band (CO) shows a small red shift at higher RHs than 60%, indicating adsorption of bound water to CO bonds. Amounts of water molecules adsorbed to ceramide are very limited due to few adsorption of free water.

Investigation of Temperature and Humidity Control System for Mushroom House

Abstract: Monitoring and control the mushroom house environment play an important role in mushroom cultivation quality. Assurance of optimal temperature and humidity has a direct influence on the mushroom growth performance. Traditionally, mushroom cultivation has required a great effort to connect and distribute all the sensors and data acquisition systems. Natural environment such as the temperature during the day either on a hot day and the rain is affecting the temperature and moisture in the mushroom house directly. The optimal temperature and humidity for mushroom house is around 20°C and 80% respectively. For this reason, in order to maintain an optimal temperature and humidity, Matlab Simulink was developed to run simulations on the system. Simulink's block diagram is composed of three main parts for this system whereas input, control system and the output temperature and humidity for the mushroom house. Matlab/Simulink tool is use for modeling, simulating and analyzing the performance of the system.

Significance of Temperature and Humidity Control for Agricultural Products Storage: Overview of Conventional and Advanced Options

Abstract The agricultural products are perishable in nature and possesses short shelf/storage life under ambient conditions. The temperature and humidity control systems are required to enhance to storage life of the products with optimum quality, quantity and nutritive attributes. In this regard, the significance of air-conditioning in storage application is highlighted along with the conventional storage options. The implications of compressor-based refrigeration and air-conditioning systems regarding low-cost and energy efficient air-conditioning systems are discussed in detailed. It is concluded that thermally driven air-conditioning systems can be used on top priority for the short-term storage of fresh agricultural products. Moreover, the long-term storage of products at freezing temperature can be made through hybrid systems instead of standalone conventional compressor based vapor compression refrigeration and/or air-conditioning systems. Finally, the air-conditioning systems are proposed for the optimum storage of different categorize of the food products.

Automated relative humidity and temperature control system for banana tissue culture laboratory with monitoring system and SMS notification

The challenged to developers is to automate relative humidity and temperature which control and monitoring approaches is using SMS based on the notification as part of the technology innovation. Thus, it complicates in the banana tissue culture laboratory implementation to have efficient monitoring system supplements the concept of the study that makes it more interesting and timelier in the implementation of Internet of Things Approach. The project intent to help the owner to automatically control and monitor temperature and humidity in banana tissue culture laboratory to provide appropriate temperature and relative humidity for banana which is the basic requirements to maintain the fast growth and resistant to diseases and infection. The prototype was tested with a white-box testing approach which surpass the requirements to the real laboratory. A survey questionnaire was also being used as part of evaluating the functionality and usability of the prototype that a very agree on both are the result.