Comparative Analysis of the Cooling Efficiency in Tropical Climate of Three Alternative Materials for Evaporative Cooling Pads

A comparison between commercial cellulose evaporative cooling pad and pads manufactured with three alternative materials was made for environmental conditions typical of tropical countries. Wind tunnel tests were carried out to compute the convective heat and mass transfer coefficients and to measure the pressure drop across each pad, obtaining expressions that can be used as reference for future simulations. Using a mathematical model, a detailed analysis of the efficiency, Temperature–Humidity Index, temperature drop and relative humidity through the pads was performed in terms of different operative and constructive conditions, such as air velocities, dry-bulb temperatures, relative humidity and pad thickness. Significant differences between the pressure drop across the pads were found, which increases with the inlet air velocity and water flow. A weak relation between the analysed variables and the inlet air velocity was found, while a high correlation between the analysed variables, pad thickness and the external environmental conditions was established. Cooling efficiencies above 40% and a Temperature–Humidity Index below the mild zone of thermal stress were obtained for the alternative panels. Although the cellulose cooling pad showed the best behaviour in all aspects, the alternative pads can be used as substituted in specific applications to reduce the Temperature–Humidity Index inside agricultural facilities.

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Effect of Different Environmental Conditions on Some Haematological Parameters in Cow

Annals of Animal Science ◽

10.2478/aoas-2014-0049 ◽

2014 ◽

Vol 14 (4) ◽

pp. 947-954 ◽

Cited By ~ 11

Author(s):

Giuseppe Mazzullo ◽

Claudia Rifici ◽

Gino Caccamo ◽

Maria Rizzo ◽

Giuseppe Piccione

Keyword(s):

Relative Humidity ◽

Ambient Temperature ◽

Environmental Conditions ◽

Physiological Responses ◽

Repeated Measure ◽

Haematological Parameters ◽

Data Logger ◽

Temperature Humidity Index ◽

Measure Analysis ◽

Humidity Index

Abstract The aim of this study was to establish physiological responses of Piemontese cows to different environmental conditions (ambient temperature, relative humidity and temperature-humidity index). To this end, 43 clinically healthy Piemontese cows aged 2-12 years were used to evaluate the effect of environmental conditions on haematological parameters. For each period, ambient temperature and relative humidity were recorded by means of a data logger and the temperature-humidity index (THI) was calculated as indicator of thermal comfort for cattle. Blood samples were collected at 4 time points under different environmental conditions (T1, T2, T3 and T4) and analysed for haematological parameters. One way repeated measure analysis of variance showed a statistically significant effect of time (P<0.0001) on RBC, Hb, Hct, MCV, MCH, MCHC, Plt, WBC, neutrophils, lymphocytes, monocytes and eosinophils. The majority of haematological values obtained in the present study, even though within the physiological range for cattle, showed that variations in haematological parameters are related to changes in ambient temperature, relative humidity and temperature-humidity index. These results provide insight into the physiological responses of Piemontese cows to different environmental conditions, allowing to better evaluate its ability to adapt and cope with environmental stress.

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Effect of Temperature-Humidity-Index on Milk Performances of Local Born Holstein Dairy Cows Under Saharan Climate

Archiva Zootechnica ◽

10.2478/azibna-2021-0010 ◽

2021 ◽

Vol 24 (2) ◽

pp. 24-36

Author(s):

Lazoumi Ouarfli ◽

Abdelmadjid Chehma

Keyword(s):

Heat Stress ◽

Dairy Cows ◽

Environmental Conditions ◽

Arid Regions ◽

Effect Of Temperature ◽

Significant Drop ◽

Temperature Humidity Index ◽

Lactation Length ◽

Humidity Index ◽

Milking Frequency

Abstract The objective is to study the effect of heat stress on milk yield (MY) relative to milking records (n=18178) of native Holsteins (n=187), in the region of Ghardaia, according to periods of HS, using the temperature-humidity index (THI). With THI >72 during 07 months in the study area, which significantly (P<0.001) decrease the MY (-15.5% corresponding to 21.73 kg). Also, calving periods led to a significant drop (P < 0.001) in overall MY (7030.35 kg) of the order of (-14.6%), and over the lactation length (353.43 d), which explains 41% of the variations in MY. In addition, the non-significant effect (P=0.212) of the lactation range on the increase in MY, moreover, the lactation length shows a non-significant (P = 0.108) decrease (-4.68%) during heat stress (HS). Furthermore, the significant effect (P <0.001) of the interaction (Milking frequency × THI) on MY, when THI variates from < 74 to > 84, with regression of (-16.82% and -08.82%) of the MF (2X and 3X), respectively. Again, the NH cow is less sensitive to hyperthermia, so THI explains only 2% of the variation in MY levels. Thus, NH in arid regions have the ability to acclimatize to Saharan environmental conditions.

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Relation between some climate parameters inside and outside the stable in the course of the year

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun200957040125 ◽

2009 ◽

Vol 57 (4) ◽

pp. 125-132 ◽

Cited By ~ 6

Author(s):

Lucie Walterová ◽

Lenka Šarovská ◽

Daniel Falta ◽

Gustav Chládek

Keyword(s):

Relative Humidity ◽

Outdoor Temperature ◽

Climate Parameters ◽

Temperature Humidity Index ◽

Humidity Index ◽

Autumn And Winter ◽

Daily Relative Humidity ◽

Indoor And Outdoor

The objective of the present study was to evaluate the relation between some climate parameters inside and outside the stable in the course of the year. Investigations were carried out from 1 July 2007 to 30 June 2008 at the School Farm in Žabčice. We monitored the following micro-climate parameters: temperature (°C), relative humidity (%) and the temperature-humidity index (THI) inside and outside the stable. We used the statistical programme UNISTAT version 5.1.11 to calculate the average monthly temperatures, relative humidity and the THI inside and outside the stable.Measurements carried out throughout the whole year revealed that the average daily outdoor temperature was always lower than the temperature monitored inside the stable. The differences between the outdoor and indoor temperatures were more marked in winter; in summer the differences were considerably lower. The coefficient correlations confirmed this finding; the temperatures were the highest in July and the lowest in autumn and winter. The same results and tendencies were monitored in terms of the average daily THI values. Much like the temperatures also the differences in high average daily values of relative humidity between the outside and inside environment of the stable were lower. Since the relative humidity was higher in winter than in summer the differences between the indoor and outdoor stable values were more marked in summer than in winter. In contrast to the temperature and THI, in one half of the cases the average daily relative humidity was higher outside the stable than inside and vice versa.

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Effect of Lattice Setting Density on Fluid Flow and Convective Heat Transfer Characteristics of Bricks in Tunnel Kilns

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4046420 ◽

2020 ◽

Vol 12 (5) ◽

Author(s):

Mosab A. Alrahmani ◽

Issa F. Almesri ◽

Hosny Z. Abou-Ziyan ◽

Jaber H. Almutairi

Keyword(s):

Heat Transfer ◽

Pressure Drop ◽

Convective Heat Transfer ◽

Convective Heat ◽

Firing Process ◽

Pumping Power ◽

Flow Uniformity ◽

Transfer Coefficients ◽

Air Velocity ◽

Lattice Setting

Abstract This paper reports the effect of setting density on flow uniformity, pressure drop, pumping power, and convective heat transfer coefficients (CHTCs). High-density setting (HDS) comprises 768 bricks, and low-density setting (LDS) contains 512 bricks are tested for different inlet air velocities using both local and average approaches. The investigation is carried out using a 3D-computational fluid dynamics (CFD) model with k–ω turbulence model. Both settings are validated against experimental data reported in the literature with errors less than 1.9% for pressure drop and −1.0% for brick surface temperature. The reported results indicated that the LDS has distinct benefits over the HDS as it enhances the flow uniformity, particularly in the stack channels. Also, LDS attains lower pressure drop, pumping power, and firing time than HDS by 45.93%, 50%, and 35%, respectively. In addition, LDS produces larger CHTCs, rates of heat transfer for individual bricks, and the ratio of heat transfer to pumping power than HDS by 24.53%, 35%, and 34%, respectively. Moreover, LDS produces more homogenous heating of the setting bricks than HDS as the maximum difference of CHTCs between bricks is about 4.39% for LDS and 19.62% for HDS. The best performance of the firing process is accomplished at low inlet air velocity (3 m/s), whereas the highest productivity is achieved at high inlet air velocity (9 m/s).

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Microclimate in silvipastoral systems with eucalyptus in rank with different heights

Revista Brasileira de Zootecnia ◽

10.1590/s1516-35982010000300030 ◽

2010 ◽

Vol 39 (3) ◽

pp. 685-694 ◽

Cited By ~ 11

Author(s):

Wander de Souza ◽

Orlando Rus Barbosa ◽

Jair de Araújo Marques ◽

Marco Aurélio Teixeira Costa ◽

Eliane Gasparino ◽

...

Keyword(s):

Wind Speed ◽

Relative Humidity ◽

Air Temperature ◽

Thermal Load ◽

Heat Load ◽

Temperature Humidity Index ◽

Heat Load Index ◽

Humidity Index ◽

Globe Temperature ◽

Black Globe Temperature

The aim of this work was to verify if the presence of trees and its height in formed silvipastoral systems with eucalyptus planted in rank can modify the microclimate and improve the environment for bovine raising during the day in summer. It was evaluated the microclimate of the environment in formed silvipastoral systems in rank of eucalyptus with 8 m, 18 m and 28 meters of height, compared to a system no shade in the summer. The experimental design was a split plot with six hour time in sub parcels. The systems are made up of parcels and the months as block in four replications and the interaction hour × system. The air temperature, black globe temperature, relative humidity and wind speed were observed to create the following indexes for thermal comfort: temperature-humidity index; black globe-humidity index; heat load index and the radiant thermal load. Excepted for the relative humidity, there was interaction for time × system for all variables and indexes. Interaction occurred for: air temperature at 10 a.m. and 6 p.m.; wind speed from 8 a.m. to 4 p.m.; temperature humidity index at 10 a.m. and 12 p.m.; black globe temperature, black globe humidity index, heat load index, and radiant thermal load at all the hours. During the summer, the system with shade of 28 m trees had the lowest average of black globe temperature; wind speed; black globe humidity index; radiant thermal load index; and heat load index. There was a reduction of wind speed average in systems 8 m, 18 m and 28 m trees in, respectively, 20.7; 50.0 and 48.0% in relation to no shade system; however it was not proportional to the height, with influence of the rank porosity and pantries height. Nevertheless, for radiant thermal load index the reduction was proportional to the height of the trees with 10.24; 12.49 and 20.76%, respectively, for 8 m, 18 m and 28 meters of height. There was a reduction of the thermal stress in the environment due to the presence of trees, being the heat load index thermal the index that better demonstrated the effect, despite of not being proportional to the rank height.

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Studies on Condensation of Refrigerants in a High Aspect Ratio Microchannel and in a Novel Micro-Groove Surface Heat Exchanger: Development of Micro-Condensers in Compact Two Phase Cooling Systems

ASME 5th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2007-30179 ◽

2007 ◽

Cited By ~ 1

Author(s):

Serguei Dessiatoun ◽

Sourav Chowdhury ◽

Ebrahim Al-Hajri ◽

Edvin Cetegen ◽

Michael Ohadi

Keyword(s):

Heat Transfer ◽

Pressure Drop ◽

Aspect Ratio ◽

Temperature Drop ◽

Transfer Coefficients ◽

Two Phase ◽

Groove Surface ◽

Heat Transfer Coefficients ◽

Surface Condenser ◽

Two Phase Cooling

Three different refrigerants, R134a, R245fa and HFE7100 were analyzed as working fluids for two-phase cooling of high heat flux electronics in a 0.7 mm hydraulic diameter 190 mm long high aspect ratio minichannel and in a newly developed micro-groove surface condenser. The latter comprised of a micro-groove surface with rectangular grooves of 84 μm in hydraulic diameter with an aspect ratio of 10.6 and headers that directed the refrigerant flow into the grooves. It was concluded that in the minichannel R245fa provides higher heat transfer coefficients compared to R134a with a significantly higher pressure drop. The saturation temperature drop in the same channel created a significant temperature drop for HFE7100 that make the application of such minichannels for cross-flow condensers with this fluid unpractical. The microgroove surface condenser provided significantly higher heat transfer coefficients compared to the minichannel condenser. The pressure drop in the micro-groove surface condenser was extremely low and imposed just 1C temperature drop on HFE7100 at it highest heat flux. The mass flux of refrigerant in the micro-groove surface condenser is significantly lower compared to conventional mini and microchannel condensers. In its current configuration, the microgroove surface condenser benefits from the possibility of an increase in mass flux resulting in a significant increase in heat transfer coefficient and just a moderate increase in pressure drop.

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Methods of cooling subjects with hyperpyrexia

Journal of Applied Physiology ◽

10.1152/jappl.1959.14.5.771 ◽

1959 ◽

Vol 14 (5) ◽

pp. 771-776 ◽

Cited By ~ 81

Author(s):

C. H. Wyndham ◽

N. B. Strydom ◽

H. M. Cooke ◽

J. S. Maritz ◽

J. F. Morrison ◽

...

Keyword(s):

Relative Humidity ◽

Cold Water ◽

Evaporative Cooling ◽

The Body ◽

Compressed Air ◽

Water Cooling ◽

Reliable Index ◽

Air Velocity ◽

Slow Cooling ◽

Significant Difference

Six volunteers raised their rectal temperatures to 104℉ by 40–50 minutes' work at 93℉ wet-bulb temperature. The rates of fall in rectal temperatures were studied during cooling by six different methods. The most rapid method of cooling occurred when subjects sat at rest in an air condition of 90℉ dry bulb and 87℉ wet bulb and evaporative cooling was accelerated by wetting the body surface continuously for 1 hour; no significant difference in cooling was observed between airflows of 120 ft/min. and a jet of compressed air held 1–3 ft from subjects. Merely seating individuals in air conditions of 70℉ with 20% relative humidity in still air was almost as effective. Immersion in cold water and sitting in air conditions of 90℉ (D.B.) and 87℉ (W.B.) without aiding evaporative cooling are significantly less effective than the foregoing methods. Resting subjects at 97℉ (D.B.), 93℉ (W.B.) and 120 ft/min. air velocity results in very slow cooling. ‘Afterdrop’ in rectal temperature after ice-cold water cooling may be associated with severe circulatory shock. Oral temperatures are a less reliable index of core temperature than rectal. Submitted on February 16, 1959

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Perubahan Temperature Humidity Index (THI) di Pulau Jawa sejak 1981 hingga 2019

Majalah Geografi Indonesia ◽

10.22146/mgi.63432 ◽

2021 ◽

Vol 35 (2) ◽

Author(s):

Qurrata A'yun Kartika ◽

Rahmat Hidayat ◽

Rista Hernandi Virgianto

Keyword(s):

Thermal Stress ◽

Relative Humidity ◽

Air Temperature ◽

Pearson Correlation ◽

Surface Air Temperature ◽

North Coast ◽

Anthropogenic Activity ◽

Temperature Humidity Index ◽

The North ◽

Humidity Index

Abstrak Pulau Jawa mengalami peningkatan jumlah penduduk dari waktu ke waktu. Peningkatan ini berdampak pada tingginya aktivitas antropogenik yang menghasilkan emisi yang diantaranya dapat menyebabkan perubahan suhu udara. Suhu udara sangat berkaitan dengan thermal stress yang mempengaruhi kenyamanan bahkan kesehatan manusia. Thermal stress dapat diukur dengan Temperature Humidity Index (THI) dengan suhu udara rata-rata permukaan dan Relative Humidity (RH) sebagai variabel bebas. Penelitian ini menganalisis sejauh mana perubahan suhu udara permukaan, RH dan THI terhadap waktu. Kemudian daerah dengan perubahan THI yang paling besar akan dianalisis keterkaitannya jumlah penduduk menggunakan korelasi Pearson. Berdasarkan hasil penelitian diketahui terjadi perubahan suhu udara udara permukaan sebesar -0.27 hingga 1.17⁰C diikuti perubahan RH sebesar -2.21% hingga 0.77% dan terjadi perubahan THI hingga 0,72⁰C sejak 1981 hingga 2019 terutama di pesisir utara bagian barat Pulau Jawa. Selain itu, THI di sekitar DKI Jakarta juga memiliki nilai korelasi simultan yang tinggi dengan jumlah penduduk sebesar 0,81, korelasi lag 1 tahun sebesar 0,69, sementara korelasi lag 2 tahun sebesar 0,67. Temuan ini mengindikasikan peningkatan jumlah penduduk berdampak terhadap peningkatan THI pada DKI Jakarta. Abstract Java has experienced an increase in population from time to time. This increase has an impact on high anthropogenic activity which results in emissions, which can cause changes in air temperature. Air temperature is closely related to thermal stress which affects comfort and even human health. Thermal stress can be measured by the Temperature Humidity Index (THI) with the average surface air temperature and Relative Humidity (RH) as the independent variable. This study analyzes the extent of changes in surface air temperature, RH and THI with time. Then the areas with the greatest THI changes will be analyzed for their correlation using the Pearson correlation. Based on the research results, it is found that there has been a change in surface air temperature of -0.27 to 1.17⁰C followed by changes in RH from -2.21% to 0.77% and there has been a change in THI to 0.72⁰C from 1981 to 2019, especially on the north coast of the western part of Java. In addition, THI around DKI Jakarta also has a high simultaneous correlation value with a population of 0.81, a 1-year lag correlation of 0.69, while a 2-year lag correlation of 0.67. These findings indicate an increase in population has an impact on increasing THI in DKI Jakarta.

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Thermal Comfort At The Street Corridor Around Public Places, Case Study Alun-Alun Malang City

Journal of Islamic Architecture ◽

10.18860/jia.v3i4.3102 ◽

2016 ◽

Vol 3 (4) ◽

pp. 177 ◽

Cited By ~ 1

Author(s):

Erna Winansih ◽

Antariksa Antariksa ◽

Surjono Surjono ◽

Amin Setyo Leksono

Keyword(s):

Relative Humidity ◽

Thermal Comfort ◽

The South ◽

Index Method ◽

Public Places ◽

South Side ◽

Temperature Humidity Index ◽

Humidity Index

Malang as the second largest city in East Java province become crowded recently. The congestion almost happens everyday. The scenery of the street corridor is full of iron stacks. It is said that Malang city is less comfortable and less walkable. The decrease of this environment encourages to conduct the study (Q.S. 16:90, Q.S. 96:1-5, Q.S. 30:41). The study aimed to analyze the thermal comfort at pedestrian ways around Malang city squares, the street corridor of Merdeka Alun-Alun (MAA) and the Tugu Alun-Alun (TAA). The temperature and relative humidity were measured by multinorm instrument. The THI (Temperature Humidity Index) method was used to analyze the thermal comfort. The results showed that the THI average at TAA (27) were more comfortable than at MAA (27,5). The south side of the MAA corridor became the most comfortable with the THI value of 26,4, which the side covered by trees canopy (Q.S. 7:58). It needs to conduct next research (Q.S. 13:11), because of the change of the activities at these street corridors.

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IDENTIFIKASI IKLIM MIKRO DAN KENYAMAN TERMAL RUANG TERBUKA HIJAU DI KENDARI

NALARs ◽

10.24853/nalars.18.1.23-34 ◽

2019 ◽

Vol 18 (1) ◽

pp. 23

Author(s):

Santi Santi ◽

Siti Belinda ◽

Hapsa Rianty

Keyword(s):

Wind Speed ◽

Relative Humidity ◽

Open Space ◽

Heat Island ◽

Open Spaces ◽

Temperature Humidity Index ◽

Humidity Index ◽

Urban Heat ◽

The City

ABSTRAK. Fenomena UHI (Urban Heat Island) mengakibatkan suhu udara perkotaan menjadi tinggi, sehingga menurunkan kualitas lingkungan kota. Untuk dapat meningkatkan kualitas kota dan mengimbangi pertumbuhan kota, maka pemerintah menggalakkan pengembangan infrastruktur hijau perkotaan melalui pengembangan Ruang Terbuka Hijau (RTH). Kota Kendari memiliki beberapa ruang terbuka yang beberapa diantaranya merupakan pusat aktifitas dan interaksi masyarakat kota, diantaranya Taman Walikota dan Pelataran Tugu Religi. Penelitian ini merupakan penelitian deskriptif untuk mengetahui kondisi iklim mikro dan kenyamanan termal ruang terbuka. Data-data yang dikumpulkan berupa karakteristik dan nilai indikator iklim mikro yang meliputi suhu udara, kelembaban relatif, dan kecepatan angin pada sejumlah titik ukur pada siang hari. Data yang dikumpulkan dianalisis menggunakan uji Statistik Independent T Test untuk mengetahui perbedaan iklim mikro antara kedua lokasi dan analisis Temperature Humidity Index (THI) untuk mengetahui tingkat kenyamanannya. Hasil dari uji statistik menunjukkan tingkat perbedaan yang tidak sigifikan antara kedua lokasi, meliputi suhu udara (sig.=0,283); kelembaban relatif (sig.=0,115); dan kecepatan angin (sig.=0,105). Sementara itu, melalui analisia THI menunjukkan nilai index tidak nyaman hampir terjadi pada keseluruhan titik ukur. Nilai THI tertinggi pada lokasi Taman Walikota terletak pada titik A5 (THI=31,9), yaitu pada daerah memiliki kecepatan angin rendah karena posisinya pada bagian tengah kawasan. Sedangkan pada lokasi pelataran Tugu Religi, nilai terendah THI diperoleh pada titik B9 (THI=33,12), yakni titik yang sebagian besar material permukaan lahannya berupa aspal. Kata kunci: ruang terbuka, temperatur, angin, kelembaban relatif, Temperature Humidity Index ABSTRACT. The UHI (Urban Heat Island) phenomenon affected urban air temperatures become high, which decreases the quality of the city environment. To be able to improve the quality of the city and to balance the growth of the city, the government promotes the development of urban green infrastructure through the development of Green Open Space (RTH). Kendari City has several open spaces, some of which are the center of the activities and interactions of urban communities, including the Taman Walikota and the Pelataran Tugu Religi. This research is a descriptive study to determine the microclimate conditions and thermal comfort of open spaces. The data collected is in the form of characteristics and values of microclimate indicators which include air temperature, relative humidity, and wind speed at some measuring points during the day. The collected data were analyzed using the Independent T-Test Statistic Test to determine the differences in microclimate between the two locations and the Temperature Humidity Index (THI) analysis to determine the level of comfort. The results of the statistical tests show a significant level of difference between the two locations, including air temperature (sig. = 0.283); relative humidity (sig. = 0.115); and wind speed (sig. = 0.105). Meanwhile, through THI analysis, the uncomfortable index value almost occurs at the whole measuring point. The highest THI value in the location of the Taman Walikota is located at point A5 (THI = 31.9), which is in the area with low wind speed because of its position in the central part of the city. Whereas in the location of the Pelataran Tugu Religi, the lowest value of THI is obtained at point B9 (THI = 33.12), which is the point where most of the surface material in the land is asphalt. Keywords: open space, temperature, wind, relative humidity, Temperature Humidity Index

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