Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 512

Search results for: humidity

512 A Fabrication Method for PEDOT: PSS Based Humidity Sensor

Authors: Nazia Tarannum, M. Ayaz Ahmad

Abstract:

The main goal of this article is to report some interesting features for the fabrication/design of PEDOT:PSS based humidity sensor. Here first we fabricated humidity sensor and then studied its electro-mechanical characteristics. In general the humidity plays an important role in various private and government sectors all over the world. Monitoring and controlling the humidity is a great task for the reliable operation of various systems. The PEDOT:PSS is very much promising humidity sensor and also is fabricated by performing various analyses. The interdigited electrode (IDE) has channel length 200 microns prepared by lithography. Lithography of IDE was done on PPR coated glass substrate using negative mask and exposing it with UV light for 10 secs via DSA. During the above said fabrication, we have taken account for the following steps: •Plasma ashing of IDE •Spincoating of PEDOT:PSS was done @3000 rpm on IDE substrace •Baked the substrace at 130 °C up to time limit 15 mins. •Resistance measurement using Labtracer 2.9 software via Keithley 2400source meter.

Keywords: fabrication method, PEDOT:PSS material, humidity sensor, electro-mechanical

Procedia PDF Downloads 241
511 Gate Voltage Controlled Humidity Sensing Using MOSFET of VO2 Particles

Authors: A. A. Akande, B. P. Dhonge, B. W. Mwakikunga, A. G. J. Machatine

Abstract:

This article presents gate-voltage controlled humidity sensing performance of vanadium dioxide nanoparticles prepared from NH4VO3 precursor using microwave irradiation technique. The X-ray diffraction, transmission electron diffraction, and Raman analyses reveal the formation of VO2 (B) with V2O5 and an amorphous phase. The BET surface area is found to be 67.67 m2/g. The humidity sensing measurements using the patented lateral-gate MOSFET configuration was carried out. The results show the optimum response at 5 V up to 8 V of gate voltages for 10 to 80% of relative humidity. The dose-response equation reveals the enhanced resilience of the gated VO2 sensor which may saturate above 272% humidity. The response and recovery times are remarkably much faster (about 60 s) than in non-gated VO2 sensors which normally show response and recovery times of the order of 5 minutes (300 s).

Keywords: VO2, VO2(B), MOSFET, gate voltage, humidity sensor

Procedia PDF Downloads 220
510 Analysis and Measurement on Indoor Environment of University Dormitories

Authors: Xuechen Gui, Senmiao Li, Qi Kan

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Dormitory is a place for college students to study and live their daily life. The indoor environment quality of the dormitory is closely related to the physical health, mood status and work efficiency of the dormitory students. In this paper, the temperature, humidity and carbon dioxide concentration of the dormitory in Zijingang campus of Zhejiang University have been tested for three days. The experimental results show that the concentration of carbon dioxide is related to the size of the window opens and the number of dormitory staff, and presents a high concentration of carbon dioxide at nighttime while a low concentration at daytime. In terms of temperature and humidity, there is no significant difference between different orientation and time and presents a small humidity at daytime while a high humidity at nighttime.

Keywords: dormitory, indoor environment, temperature, relative humidity, carbon dioxide concentration

Procedia PDF Downloads 60
509 Measurement of Temperature, Humidity and Strain Variation Using Bragg Sensor

Authors: Amira Zrelli, Tahar Ezzeddine

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Measurement and monitoring of temperature, humidity and strain variation are very requested in great fields and areas such as structural health monitoring (SHM) systems. Currently, the use of fiber Bragg grating sensors (FBGS) is very recommended in SHM systems due to the specifications of these sensors. In this paper, we present the theory of Bragg sensor, therefore we try to measure the efficient variation of strain, temperature and humidity (SV, ST, SH) using Bragg sensor. Thus, we can deduce the fundamental relation between these parameters and the wavelength of Bragg sensor.

Keywords: Fiber Bragg Grating Sensors (FBGS), strain, temperature, humidity, structural health monitoring (SHM)

Procedia PDF Downloads 188
508 Energy Saving in Handling the Air-Conditioning Latent-Load Using a Liquid Desiccant Air Conditioner: Parametric Experimental Analysis

Authors: Mustafa Jaradat

Abstract:

Reasonable energy saving for dehumidification is feasible with the use of desiccants. Desiccants are able to lower the humidity content in the air irrespective of the dew point temperature. In this paper, a tube bundle liquid desiccant air conditioner was experimentally designed and evaluated using lithium chloride as a desiccant. Several experiments were conducted to evaluate the influence of the inlet parameters on the dehumidifier performance. The results show a reduction in the relative humidity in the range of 17 to 46%, and the change in the humidity ratio was between 1.5 to 4.7 g/kg, depending on the inlet conditions. A water removal rate in the range between 0.54 and 1.67 kg/h was observed. The effects of air relative humidity and the desiccant flow rate on the dehumidifier’s performance were investigated. It was found that the moisture removal rate remarkably increased with increasing desiccant flow rate and air inlet humidity ratio. The dehumidifier effectiveness increased sharply with increasing desiccant flow rate. Also, it was found that the dehumidifier effectiveness slightly decreased with air humidity ratio.

Keywords: air conditioning, dehumidification, desiccant, lithium chloride, tube bundle

Procedia PDF Downloads 46
507 Effect of Relative Humidity on Corrosion Behavior of SN-0.7Cu Solder under Polyvinyl Chloride Fire Smoke Atmosphere

Authors: Qian Li, Shouxiang Lu

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With the rapid increase in electric power use, wire and cable fire occur more and more frequent. The fire smoke has a corrosive effect on the solders, which seriously affects the function of electronic equipment. In this research, the effect of environment relative humidity on corrosion behavior of Sn-0.7Cu solder has been researched under 140 g·m⁻³ polyvinyl chloride (PVC) fire smoke atmosphere. The mass loss of Sn-0.7Cu solder increased with the relative humidity. Furthermore, the microstructures and corrosion mechanism were analyzed by using SEM, EDS, XRD, and XPS. The result shows that Sn₂₁Cl₁₆(OH)₁₄O₆ is the main corrosion products and the corrosion process is an electrochemical reaction. The present work could provide guidance to the risk assessment for electronic equipment rescue after a fire.

Keywords: corrosion, fire smoke, relative humidity, Sn-0.7Cu solder

Procedia PDF Downloads 42
506 A Method for Calculating Dew Point Temperature in the Humidity Test

Authors: Wu Sa, Zhang Qian, Li Qi, Wang Ye

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Currently in humidity tests having not put the Dew point temperature as a control parameter, this paper selects wet and dry bulb thermometer to measure the vapor pressure, and introduces several the saturation vapor pressure formulas easily calculated on the controller. Then establish the Dew point temperature calculation model to obtain the relationship between the Dew point temperature and vapor pressure. Finally check through the 100 groups of sample in the range of 0-100 ℃ from "Psychrometric handbook", find that the average error is small. This formula can be applied to calculate the Dew point temperature in the humidity test.

Keywords: dew point temperature, psychrometric handbook, saturation vapor pressure, wet and dry bulb thermometer

Procedia PDF Downloads 276
505 Heat and Humidity Induced Plastic Changes in Body Lipids and Starvation Resistance in the Tropical Zaprionus indianus of Wet-Dry Seasons

Authors: T. N. Girish, B. E. Pradeep, Ravi Parkash

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Insects from tropical wet or dry seasons are likely to cope starvation stress through seasonal phenotypic plasticity in energy metabolites. Accordingly, we analyzed such plastic changes in Zaprionus indianus flies reared under wet or dry season-specific conditions; and also after adult acclimation at 32℃ for 1 to 6 days; and to low (40% RH) or high (70% RH) humidity. Both thermal or humidity acclimation revealed significant accumulation of body lipids for wet season flies but low humidity acclimation did not change the level of body lipids in dry season flies. Developmental and adult acclimation showed sex specific differences i.e., starvation resistance and body lipids were higher in the males of dry season but in females of wet season. We found seasonal and sex specific differences in the relative level for body lipids at death; and in the rates of accumulation or utilization of energy metabolites (body lipids, carbohydrates and proteins). Body lipids constitute the preferred energy source under starvation for flies of both the seasons. However, utilization of carbohydrates (~20% to 30%) and proteins (~20% to 25%) was evident only in dry season flies. Higher starvation resistance after thermal or humidity acclimation is achieved by increased accumulation of lipids. Adult acclimation of wet or dry season flies revealed plastic changes in mean daily fecundity despite reduction in fecundity under starvation. Thus, thermal or humidity induced plastic responses in body lipids support starvation resistance under wet or dry seasons.

Keywords: heat or humidity acclimation, plastic changes in body lipids and starvation resistance, tropical drosophilid, Wet- or Dry seasons, Zaprionus indianus

Procedia PDF Downloads 58
504 Modelling and Management of Vegetal Pest Based On Case of Xylella Fastidiosa in Alicante

Authors: Maria Teresa Signes Pont, Jose Juan Cortes Plana

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Our proposal provides suitable modelling to the spread of plant pest and particularly to the propagation of Xylella fastidiosa in the almond trees. We compared the impact of temperature and humidity on the propagation of Xylella fastidiosa in various subspecies. Comparison between Balearic Islands and Alicante (Spain). Most sharpshooter and spittlebug species showed peaks in population density during the month of higher mean temperature and relative humidity (April-October), except for the splittlebug Clastoptera sp.1, whose adult population peaked from September-October (late summer and early autumn). The critical season is from when they hatch from the eggs until they are in the pre-reproductive season (January -April) to expand. We focused on winters in the egg state, which normally hatches in early March. The nymphs secrete a foam (mucilage) in which they live and that protects them from natural enemies of temperature changes and prevents dry as long as the humidity is above 75%. The interaction between the life cycles of vectors and vegetation influences the food preferences of vectors and is responsible for the general seasonal shift of the population from vegetation to trees and vice versa, In addition to the temperature maps, we have observed humidity as it affects the spread of the pest Xylella fastidiosa (Xf).

Keywords: xylella fastidiosa, almod tree, temperature, humidity, environmental model

Procedia PDF Downloads 36
503 Humidity Sensing Behavior of Graphene Oxide on Porous Silicon Substrate

Authors: Amirhossein Hasani, Shamin Houshmand Sharifi

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In this work, we investigate humidity sensing behavior of the graphene oxide with porous silicon substrate. By evaporation method, aluminum interdigital electrodes have been deposited onto porous silicon substrate. Then, by drop-casting method graphene oxide solution was deposited onto electrodes. The porous silicon was formed by electrochemical etching. The experimental results showed that using porous silicon substrate, we obtained two times larger sensitivity and response time compared with the results obtained with silicon substrate without porosity.

Keywords: graphene oxide, porous silicon, humidity sensor, electrochemical

Procedia PDF Downloads 495
502 Termite Brick Temperature and Relative Humidity by Continuous Monitoring Technique

Authors: Khalid Abdullah Alshuhail, Syrif Junidi, Ideisan Abu-Abdoum, Abdulsalam Aldawoud

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For the intention of reducing energy consumption, a proposed construction brick was made of imitation termite mound soil referred here as termite brick (TB). To calculate the thermal performance, a real case model was constructed by using this biomimetic brick for testing purposes. This paper aims at investigating the thermal performance of this brick during different climatic months. Its thermal behaviour was thoroughly studied over the course of four months by using continuous method (CMm). The main parameters were focused on temperature and relative humidity. It was found that the TB does not perform similarly in all four months and/or in all orientations. Each four-month model study was deeply analyzed. By using the CMm method, the model was also examined. The measuring period shows generally that internal temperature and internal humidity are higher in the roof within 2 degrees and lowest at north wall orientation. The relative humidity was also investigated systematically. The paper reveals more interesting findings.

Keywords: building material, continious monitoring, orientation, wall, temprature

Procedia PDF Downloads 30
501 Impact of Masonry Joints on Detection of Humidity Distribution in Aerated Concrete Masonry Constructions by Electric Impedance Spectrometry Measurements

Authors: Sanita Rubene, Martins Vilnitis, Juris Noviks

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Aerated concrete is a load bearing construction material, which has high heat insulation parameters. Walls can be erected from aerated concrete masonry constructions and in perfect circumstances additional heat insulation is not required. The most common problem in aerated concrete heat insulation properties is the humidity distribution throughout the cross section of the masonry elements as well as proper and conducted drying process of the aerated concrete construction because only dry aerated concrete masonry constructions can reach high heat insulation parameters. In order to monitor drying process of the masonry and detect humidity distribution throughout the cross section of aerated concrete masonry construction application of electrical impedance spectrometry is applied. Further test results and methodology of this non-destructive testing method is described in this paper.

Keywords: aerated concrete, electrical impedance spectrometry, humidity distribution, non-destructive testing

Procedia PDF Downloads 219
500 Comfort Sensor Using Fuzzy Logic and Arduino

Authors: Samuel John, S. Sharanya

Abstract:

Automation has become an important part of our life. It has been used to control home entertainment systems, changing the ambience of rooms for different events etc. One of the main parameters to control in a smart home is the atmospheric comfort. Atmospheric comfort mainly includes temperature and relative humidity. In homes, the desired temperature of different rooms varies from 20 °C to 25 °C and relative humidity is around 50%. However, it varies widely. Hence, automated measurement of these parameters to ensure comfort assumes significance. To achieve this, a fuzzy logic controller using Arduino was developed using MATLAB. Arduino is an open source hardware consisting of a 24 pin ATMEGA chip (atmega328), 14 digital input /output pins and an inbuilt ADC. It runs on 5v and 3.3v power supported by a board voltage regulator. Some of the digital pins in Aruduino provide PWM (pulse width modulation) signals, which can be used in different applications. The Arduino platform provides an integrated development environment, which includes support for c, c++ and java programming languages. In the present work, soft sensor was introduced in this system that can indirectly measure temperature and humidity and can be used for processing several measurements these to ensure comfort. The Sugeno method (output variables are functions or singleton/constant, more suitable for implementing on microcontrollers) was used in the soft sensor in MATLAB and then interfaced to the Arduino, which is again interfaced to the temperature and humidity sensor DHT11. The temperature-humidity sensor DHT11 acts as the sensing element in this system. Further, a capacitive humidity sensor and a thermistor were also used to support the measurement of temperature and relative humidity of the surrounding to provide a digital signal on the data pin. The comfort sensor developed was able to measure temperature and relative humidity correctly. The comfort percentage was calculated and accordingly the temperature in the room was controlled. This system was placed in different rooms of the house to ensure that it modifies the comfort values depending on temperature and relative humidity of the environment. Compared to the existing comfort control sensors, this system was found to provide an accurate comfort percentage. Depending on the comfort percentage, the air conditioners and the coolers in the room were controlled. The main highlight of the project is its cost efficiency.

Keywords: arduino, DHT11, soft sensor, sugeno

Procedia PDF Downloads 202
499 Indoor Microclimate in a Historic Library: Considerations on the Positive Effect of Historic Books on the Stability of Indoor Relative Humidity

Authors: Magda Posani, Maria Do Rosario Veiga, Vasco Peixoto De Freitas

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The presented research considers the hygrothermal data acquired in the municipal library of Porto. The library is housed in an XVIII century convent and, among all the rooms in the construction, one, in particular, was chosen for the monitoring campaign because of the presence of a great number of historic books. Temperature and relative humidity, as well as CO₂ concentration, were measured for six consecutive months, in the period December 24th - June 24th. The indoor environment of the building is controlled with a heating and cooling system that is turned on only during the opening hours of the library. The ventilation rate is low because the windows are kept closed, and there is no forced ventilation. The micro-climate is analyzed in terms of users’ comfort and degradation risks for historic books and valuable building surfaces. Through a comparison between indoor and outdoor measured hygrothermal data, indoor relative humidity appears very stable. The influence of the hygroscopicity of books on the stabilization of indoor relative humidity is therefore investigated in detail. The paper finally discusses the benefits given by the presence of historic books in libraries with intermittent heating and cooling. The possibility of obtaining a comfortable and stable indoor climate with low use of HVAC systems in these conditions, while avoiding degradation risks for books and historic building components, is further debated.

Keywords: books, historic buildings, hygroscopicity, relative humidity

Procedia PDF Downloads 40
498 Study of Some Epidemiological Factors Influencing the Disease Incidence in Chickpea (Cicer Arietinum L.)

Authors: Muhammad Asim Nazir

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The investigations reported in this manuscript were carried on the screening of one hundred and seventy-eight chickpea germplasm lines/cultivars against wilt disease, caused by Fusarium oxysporum f. sp. ciceris. The screening was conducted in vivo (field) conditions. The field screening was accompanied with the study of some epidemiological factors affecting the occurrence and severity of the disease. Among the epidemiological factors maximum temperature range (28-40°C), minimum temperature range (12-24°C), relative humidity (19-44%), soil temperature (26-41°C) and soil moisture range (19-34°C) was studied for affecting the disease incidence/severity. The results revealed that air temperature was positively correlated with diseases. Soil temperature data revealed that in all cultivars disease incidence was maximum as 39°C. Most of the plants show 40-50% disease incidence. Disease incidence decreased at 33.5°C. The result of correlation of relative humidity of air and wilt incidence revealed that all cultivars/lines were negatively correlated with relative humidity. With increasing relative humidity wilt incidence decreased and vice versa.

Keywords: chickpea, epidemiological, screening, disease

Procedia PDF Downloads 527
497 Higher Relative Humidity from Pipping Increases Physical Problems in the Broiler Chicks

Authors: M. A. Nogueira, M. Thimotheo, G. C. Ripamonte, S. C. C. Aguiar, M. H. S. Ulian, J. C. Goncalves Netto, I. C. Boleli

Abstract:

Increasing in the relative humidity during the last incubation day is a usual practice in the commercial hatchery to facilitate hatching. This study analyzed whether higher relative humidity improves eclodibility as well as chick quality, and alters the hatch window. Fertile eggs (65- 67g) produced by 53 weeks old broiler breeders (Cobb 500®) were incubated at 37.5°C and 31°C in the wet bulb in incubators with automatic control of temperature and egg turning (1 each hour). Two-hundred ten were distributed randomly in three treatments: 31°C in the wet bulb from internal pipping (BI-31), 33°C from internal pipping (BI-33), and 33°C from external pipping (BE-33), all three hatchers maintained at 37.5°C and without egg turning. For this, eggs were checked for internal pipping by ovoscopy and external pipping by visual observation through the transparent cover of the incubators each hour from day 18 of incubation. No significant differences in the hatchability (BI-31:79.61%, BI-33:77.63%, BE-33:80.77%; by Q-square test, P > 0.05). Absence of significant effects of the treatments were also observed for incubation duration (BI-31:488.58 h, BI-33:488.30 h, BE-33:489.04 h), and chick body weight (BI-31: 49.40g, BI-33: 49.74g, BE-33: 49.34g) and quality scores (BI-31: 90.02, BI-33: 87.56, BE-33: 92.28 points), by variance analysis (P > 0.05). However, BI-33 increased the incidence of feathering and leg problems and remaining of alantoic membrane, and BE-33 increased the incidence of problems with feathering, navel and yolk sac and reduced the leg problems, compared to BI-31. In sum, the results show higher relative humidity from internal or external pipping did not influence hatchability and incubation duration, but reduced chick quality, affecting the incubation efficiency.

Keywords: chick quality, hatchability, hatcher humidity, incubation duration

Procedia PDF Downloads 76
496 The Effect of Wet Cooling Pad Thickness and Geometric Configuration to Enhance Evaporative Cooler Saturation Efficiency: A Review

Authors: Biruk Abate

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Evaporative cooling occurs when air with high temperature and reduced humidity passes over a wet porous surface and a higher degree of cooling process is achieved for storage of fruits and vegetables due to greater rate of evaporation. The main objective of this reviewed study is to understand the effect of evaporative surface pad thickness and geometric configuration on the saturation efficiency of evaporative cooler and to state some related factors affecting the performance of the system. From this overview, selection of pad thickness and geometrical shape with suitable characteristics of heat and mass transfer and water holding capacity of the pads was reviewed as these parameters are important for saturation efficiency of evaporative cooling. Increasing the cooling pad thickness through increasing the face velocity increases the effectiveness of wet-bulb saturation. Increasing ambient temperature, inlet air speed and ambient air humidity decreases the wet bulb effectiveness and it increases with increasing length of the pad. Increasing the ambient temperature and inlet air velocity decreases the humidity ratio, but increases with increasing ambient air humidity and lengths of the pad. Increasing the temperature-humidity index is possible with increasing ambient temperature, inlet air velocity, ambient air humidity and pad length. Generally, all materials having a higher wetted surface area per unit volume give higher efficiency. Materials with higher thickness increase the wetted surface area for better mix-up of air and water to give higher efficiency for the same shape and this in turn helps to store fruits and vegetables.

Keywords: Degree of cooling, heat and mass transfer, evaporative cooling, porous surface

Procedia PDF Downloads 34
495 Thermo-Aeraulic Studies of a Multizone Building Influence of the Compactness Index

Authors: S. M. A. Bekkouche, T. Benouaz, M. K. Cherier, M. Hamdani, M. R. Yaiche, N. Benamrane

Abstract:

Most codes of building energy simulation neglect the humidity or well represent it with a very simplified method. It is for this reason that we have developed a new approach to the description and modeling of multizone buildings in Saharan climate. The thermal nodal method was used to apprehend thermoaeraulic behavior of air subjected to varied solicitations. In this contribution, analyzing the building geometry introduced the concept of index compactness as "quotient of external walls area and volume of the building". Physical phenomena that we have described in this paper, allow to build the model of the coupled thermoaeraulic behavior. The comparison shows that the found results are to some extent satisfactory. The result proves that temperature and specific humidity depending on compactness and geometric shape. Proper use of compactness index and building geometry parameters will noticeably minimize building energy.

Keywords: multizone model, nodal method, compactness index, specific humidity, temperature

Procedia PDF Downloads 306
494 Long-Term Indoor Air Monitoring for Students with Emphasis on Particulate Matter (PM2.5) Exposure

Authors: Seyedtaghi Mirmohammadi, Jamshid Yazdani, Syavash Etemadi Nejad

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One of the main indoor air parameters in classrooms is dust pollution and it depends on the particle size and exposure duration. However, there is a lake of data about the exposure level to PM2.5 concentrations in rural area classrooms. The objective of the current study was exposure assessment for PM2.5 for students in the classrooms. One year monitoring was carried out for fifteen schools by time-series sampling to evaluate the indoor air PM2.5 in the rural district of Sari city, Iran. A hygrometer and thermometer were used to measure some psychrometric parameters (temperature, relative humidity, and wind speed) and Real-Time Dust Monitor, (MicroDust Pro, Casella, UK) was used to monitor particulate matters (PM2.5) concentration. The results show the mean indoor PM2.5 concentration in the studied classrooms was 135µg/m3. The regression model indicated that a positive correlation between indoor PM2.5 concentration and relative humidity, also with distance from city center and classroom size. Meanwhile, the regression model revealed that the indoor PM2.5 concentration, the relative humidity, and dry bulb temperature was significant at 0.05, 0.035, and 0.05 levels, respectively. A statistical predictive model was obtained from multiple regressions modeling for indoor PM2.5 concentration and indoor psychrometric parameters conditions.

Keywords: classrooms, concentration, humidity, particulate matters, regression

Procedia PDF Downloads 194
493 Smart Irrigation System

Authors: Levent Seyfi, Ertan Akman, Tuğrul C. Topak

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In this study, irrigation automation with electronic sensors and its control with smartphones were aimed. In this context, temperature and soil humidity measurements of the area irrigated were obtained by temperature and humidity sensors. A micro controller (Arduino) was utilized for accessing values of these parameters and controlling the proposed irrigation system. The irrigation system could automatically be worked according to obtained measurement values. Besides, a GSM module used together with Arduino provided that the irrigation system was in connection to smartphones. Thus, the irrigation system can be remotely controlled. Not only can we observe whether the irrigation system is working or not via developed special android application but also we can see temperature and humidity measurement values. In addition to this, if desired, the irrigation system can be remotely and manually started or stopped regardless of measured sensor vales thanks to the developed android application. In addition to smartphones, the irrigation system can be alternatively controlled via the designed website (www.sulamadenetim.com).

Keywords: smartphone, Android Operating System, sensors, irrigation System, arduino

Procedia PDF Downloads 472
492 Experimental Investigation of Counter-Flow Ranque–Hilsch Vortex Tube Using Humid Air

Authors: Hussein M. Maghrabie, M. Attalla, Hany. A. Mohamed, M. Salem, E. Specht

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An experimental investigation is carried out on counter-flow Ranque–Hilsch vortex tube (RHVT). The present work is carried out to study the effect of nozzle aspect ratio, tube length and the inlet pressure (P_i) on the coefficient of performance and energy separation of a RHVT. Further, the effect of moist air with different relative humidity (RH) 40, 60, 80 % is also achieved. The air relative humidity is adjusted using air humidification/dehumidification unit. The experimental study accomplished for number of nozzle N=6, with inner diameter D=7.5 mm., and length of the vortex tube (L) 75, 97.5, and 112.5 mm. The results show that the relative humidity has a significant effect on coefficient of performance and energy separation of a RHVT.

Keywords: COP, counter-flow Ranque–Hilsch vortex tube, energy separation, humid air

Procedia PDF Downloads 390
491 Evaluation of Air Movement, Humidity and Temperature Perceptions with the Occupant Satisfaction in Office Buildings in Hot and Humid Climate Regions by Means of Field Surveys

Authors: Diego S. Caetano, Doreen E. Kalz, Louise L. B. Lomardo, Luiz P. Rosa

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The energy consumption in non-residential buildings in Brazil has a great impact on the national infrastructure. The growth of the energy consumption has a special role over the building cooling systems, supported by the increased people's requirements on hygrothermal comfort. This paper presents how the occupants of office buildings notice and evaluate the hygrothermic comfort regarding temperature, humidity, and air movement, considering the cooling systems presented at the buildings studied, analyzed by real occupants in areas of hot and humid climate. The paper presents results collected over a long time from 3 office buildings in the cities of Rio de Janeiro and Niteroi (Brazil) in 2015 and 2016, from daily questionnaires with eight questions answered by 114 people between 3 to 5 weeks per building, twice a day (10 a.m. and 3 p.m.). The paper analyses 6 out of 8 questions, emphasizing on the perception of temperature, humidity, and air movement. Statistics analyses were made crossing participant answers and humidity and temperature data related to time high time resolution time. Analyses were made from regressions comparing: internal and external temperature, and then compared with the answers of the participants. The results were put in graphics combining statistic graphics related to temperature and air humidity with the answers of the real occupants. Analysis related to the perception of the participants to humidity and air movements were also analyzed. The hygrothermal comfort statistic model of the European standard DIN EN 15251 and that from the Brazilian standard NBR 16401 were compared taking into account the perceptions of the hygrothermal comfort of the participants, with emphasis on air humidity, taking basis on prior studies published on this same research. The studies point out a relative tolerance for higher temperatures than the ones determined by the standards, besides a variation on the participants' perception concerning air humidity. The paper presents a group of detailed information that permits to improve the quality of the buildings based on the perception of occupants of the office buildings, contributing to the energy reduction without health damages and demands of necessary hygrothermal comfort, reducing the consumption of electricity on cooling.

Keywords: thermal comfort, energy consumption, energy standards, comfort models

Procedia PDF Downloads 225
490 Insight into the Physical Ageing of Poly(Butylene Succinate)

Authors: I. Georgousopoulou, S. Vouyiouka, C. Papaspyrides

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The hydrolytic degradation of poly(butylene succinate) (PBS) was investigated when exposed to different humidity-temperature environments. To this direction different PBS grades were submitted to hydrolysis runs. Results indicated that the increment of hydrolysis temperature and relative humidity induced significant decrease in the molecular weight and thermal properties of the bioplastic. Τhe derived data can be considered to construct degradation kinetics based on carboxyl content variation versus time.

Keywords: hydrolytic degradation, physical ageing, poly(butylene succinate), polyester

Procedia PDF Downloads 218
489 Determination of the Relative Humidity Profiles in an Internal Micro-Climate Conditioned Using Evaporative Cooling

Authors: M. Bonello, D. Micallef, S. P. Borg

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Driven by increased comfort standards, but at the same time high energy consciousness, energy-efficient space cooling has become an essential aspect of building design. Its aims are simple, aiming at providing satisfactory thermal comfort for individuals in an interior space using low energy consumption cooling systems. In this context, evaporative cooling is both an energy-efficient and an eco-friendly cooling process. In the past two decades, several academic studies have been performed to determine the resulting thermal comfort produced by an evaporative cooling system, including studies on temperature profiles, air speed profiles, effect of clothing and personnel activity. To the best knowledge of the authors, no studies have yet considered the analysis of relative humidity (RH) profiles in a space cooled using evaporative cooling. Such a study will determine the effect of different humidity levels on a person's thermal comfort and aid in the consequent improvement designs of such future systems. Under this premise, the research objective is to characterise the resulting different RH profiles in a chamber micro-climate using the evaporative cooling system in which the inlet air speed, temperature and humidity content are varied. The chamber shall be modelled using Computational Fluid Dynamics (CFD) in ANSYS Fluent. Relative humidity shall be modelled using a species transport model while the k-ε RNG formulation is the proposed turbulence model that is to be used. The model shall be validated with measurements taken using an identical test chamber in which tests are to be conducted under the different inlet conditions mentioned above, followed by the verification of the model's mesh and time step. The verified and validated model will then be used to simulate other inlet conditions which would be impractical to conduct in the actual chamber. More details of the modelling and experimental approach will be provided in the full paper The main conclusions from this work are two-fold: the micro-climatic relative humidity spatial distribution within the room is important to consider in the context of investigating comfort at occupant level; and the investigation of a human being's thermal comfort (based on Predicted Mean Vote – Predicted Percentage Dissatisfied [PMV-PPD] values) and its variation with different locations of relative humidity values. The study provides the necessary groundwork for investigating the micro-climatic RH conditions of environments cooled using evaporative cooling. Future work may also target the analysis of ways in which evaporative cooling systems may be improved to better the thermal comfort of human beings, specifically relating to the humidity content around a sedentary person.

Keywords: chamber micro-climate, evaporative cooling, relative humidity, thermal comfort

Procedia PDF Downloads 73
488 Development of a Combustible Gas Detector with Two Sensor Modules to Enable Measuring Range of Low Concentration

Authors: Young Gyu Kim, Sangguk Ahn, Gyoutae Park, Hiesik Kim

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In the gas industrial fields, there are many problems to detect extremely small amounts of combustible gas (CH₄) if a conventional semiconductor is used. Those reasons are that measuring is difficult at the low concentration level, the stabilization time is long, and an initial response time is slow. In this study, we propose a method to solve these issues using two specific sensors to overcome the circumstances of temperature and humidity. This idea is to combine a catalytic and a semiconductor type sensor and to utilize every advantage from every sensor’s characteristic. In order to achieve the goal, we reduced fluctuations of a gas sensor for temperature and humidity by applying designed circuits for sensing temperature and humidity. And we induced the best calibration line of gas sensors through adjusting a weight value corresponding to changeable patterns of temperature and humidity after their data are previously acquired and stored. We proposed and developed the gas leak detector using two sensor modules, which is first operated by a semiconductor sensor for measuring small gas quantities and second a catalytic type sensor is detected if measuring range of the first sensor is beyond. We conclusively verified characteristics of sharp sensitivity and fast response time against even at lower gas concentration level through experiments other than a conventional gas sensor. We think that our proposed idea is very useful if another gas leak is developed to enable measuring extremely small quantities of toxic and flammable gases.

Keywords: gas sensor, leak detector, lower concentration, and calibration

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487 Weight Loss Degradation of Hybrid Blends LLDPE/Starch/PVA Upon Exposure to UV Light and Soil Burial

Authors: Rahmah M., Noor Zuhaira Abd Aziz, Farhan M., Mohd Muizz Fahimi M.

Abstract:

Polybag and mulch film for agricultural field pose environmental wastage upon disposal. Thus a degradable polybag was designed with hybrid sago starch (SS) and polyvinyl alcohol (PVA). Two Different blended composition of SS and PVA Hybrid have been compounded. Then, the hybrids blended are mixed with linear line density polyethylene (LLDPE) resin to fabricate polybag film through conventional film blowing process. Hybrid blends was compounded at different ratios. Samples of LLDPE, SS and PVA hybrid film were exposed to UV light and soil burial. The weight loss were determined during degradation process. Hybrid film by degradation of starch was found to decrease on esterification. However the hybrid film showed greater degradation in soil and uv radiation up to 60% of SS. Weight loss were also determined in control humidity oven with 70% humidity and temperature set up at 30 °C and left in humidity chamber for a month.

Keywords: LLDPE, PVA, sago starch, degradation, soil burial, uv radiation

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486 Effects of Humidity and Silica Sand Particles on Vibration Generation by Friction Materials of Automotive Brake System

Authors: Mostafa M. Makrahy, Nouby M. Ghazaly, G. T. Abd el-Jaber

Abstract:

This paper presents the experimental study of vibration generated by friction materials of an automotive disc brake system using brake test rig. Effects of silica sand particles which are available on the road surface as an environmental condition with a size varied from 150 μm to 600 μm are evaluated. Also, the vibration of the brake disc is examined against the friction material in humidity environment conditions under variable rotational speed. The experimental results showed that the silica sand particles have significant contribution on the value of vibration amplitude which enhances with increasing the size of silica sand particles at different speed conditions. Also, it is noticed that the friction material is sensitive to humidity and the vibration magnitude increases under wet testing conditions. Moreover, it can be reported that with increasing the applied pressure and rotational speed of the braking system, the vibration amplitudes decrease for all cases.

Keywords: disc brake vibration, friction-induced vibration, silica sand particles, brake operational and environmental conditions

Procedia PDF Downloads 37
485 Effect of Wind and Humidity on Microwave Links in North West Libya

Authors: M. S. Agha, A. M. Eshahiry, S. A. Aldabbar, Z. M. Alshahri

Abstract:

The propagation of microwave is affected by rain and dust particles causing signal attenuation and de-polarization. Computations of these effects require knowledge of the propagation characteristics of microwave and millimeter wave energy in the climate conditions of the studied region. This paper presents effect of wind and humidity on wireless communication such as microwave links in the North West region of Libya (Al-Khoms). The experimental procedure is done on three selected antennae towers (Nagaza station, Al-Khoms center station, Al-Khoms gateway station) for determining the attenuation loss per unit length and cross-polarization discrimination (XPD) change. Dust particles are collected along the region of the study, to measure the particle size distribution (PSD), calculate the concentration, and chemically analyze the contents, then the dielectric constant can be calculated. The results show that humidity and dust, antenna height and the visibility affect both attenuation and phase shift; in which, a few considerations must be taken into account in the communication power budget.

Keywords: : Attenuation, scattering, transmission loss.

Procedia PDF Downloads 128
484 The Impact of Vertical Velocity Parameter Conditions and Its Relationship with Weather Parameters in the Hail Event

Authors: Nadine Ayasha

Abstract:

Hail happened in Sukabumi (August 23, 2020), Sekadau (August 22, 2020), and Bogor (September 23, 2020), where this extreme weather phenomenon occurred in the dry season. This study uses the ERA5 reanalysis model data, it aims to examine the vertical velocity impact on the hail occurrence in the dry season, as well as its relation to other weather parameters such as relative humidity, streamline, and wind velocity. Moreover, HCAI product satellite data is used as supporting data for the convective cloud development analysis. Based on the results of graphs, contours, and Hovmoller vertical cut from ERA5 modeling, the vertical velocity values in the 925 Mb-300 Mb layer in Sukabumi, Sekadau, and Bogor before the hail event ranged between -1.2-(-0.2), -1.5-(-0.2), -1-0 Pa/s. A negative value indicates that there is an upward motion from the air mass that trigger the convective cloud growth, which produces hail. It is evidenced by the presence of Cumulonimbus cloud on HCAI product when the hail falls. Therefore, the vertical velocity has significant effect on the hail event. In addition, the relative humidity in the 850-700 Mb layer is quite wet, which ranges from 80-90%. Meanwhile, the streamline and wind velocity in the three regions show the convergence with slowing wind velocity ranging from 2-4 knots. These results show that the upward motion of the vertical velocity is enough to form the wet atmospheric humidity and form a convergence for the growth of the convective cloud, which produce hail in the dry season.

Keywords: hail, extreme weather, vertical velocity, relative humidity, streamline

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483 Assessment of Personal Level Exposures to Particulate Matter among Children in Rural Preliminary Schools as an Indoor Air Pollution Monitoring

Authors: Seyedtaghi Mirmohammadi, J. Yazdani, S. M. Asadi, M. Rokni, A. Toosi

Abstract:

There are many indoor air quality studies with an emphasis on indoor particulate matters (PM2.5) monitoring. Whereas, there is a lake of data about indoor PM2.5 concentrations in rural area schools (especially in classrooms), since preliminary children are assumed to be more defenseless to health hazards and spend a large part of their time in classrooms. The objective of this study was indoor PM2.5 concentration quality assessment. Fifteen preliminary schools by time-series sampling were selected to evaluate the indoor air quality in the rural district of Sari city, Iran. Data on indoor air climate parameters (temperature, relative humidity and wind speed) were measured by a hygrometer and thermometer. Particulate matters (PM2.5) were collected and assessed by Real Time Dust Monitor, (MicroDust Pro, Casella, UK). The mean indoor PM2.5 concentration in the studied classrooms was 135µg/m3 in average. The multiple linear regression revealed that a correlation between PM2.5 concentration and relative humidity, distance from city center and classroom size. Classroom size yields reasonable negative relationship, the PM2.5 concentration was ranged from 65 to 540μg/m3 and statistically significant at 0.05 level and the relative humidity was ranged from 70 to 85% and dry bulb temperature ranged from 28 to 29°C were statistically significant at 0.035 and 0.05 level, respectively. A statistical predictive model was obtained from multiple regressions modeling for PM2.5 and indoor psychrometric parameters.

Keywords: particulate matters, classrooms, regression, concentration, humidity

Procedia PDF Downloads 203