scholarly journals Investigations of (local) thermal comfort as a function of radiation asymmetry and vertical air temperature difference

2019 ◽  
Vol 111 ◽  
pp. 02053
Author(s):  
Maximilian Beyer ◽  
Lars Schinke ◽  
Giulia Alessio ◽  
Joachim Seifert ◽  
Michele De Carli
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Temperature Difference ◽  
State Of The Art ◽  
Experimental Investigations ◽  
Air Velocity ◽  
Climate Chamber ◽  
Measurement Results ◽  
The Subject ◽  
Local Thermal Comfort

The following article describes an extract of the results of experimental investigations on the topic of thermal comfort as a function of radiation asymmetry. The investigations were carried out in the climate chamber [1, 2] of the TU Dresden with the help of subjects. The radiation asymmetry was imprinted by subdividing the climate chamber into two vertically superimposed half-rooms, one of which was heated and the other cooled. In this way, 46 experiments on the heating or cooling ceiling were carried out. The measurement results show an inseparable link between the radiation asymmetry, the vertical air temperature difference and the air velocity. The subject assessed the room climate much more negatively than the ISO 7730 [3] would predict according to the state of the art.

scholarly journals Efektifitas Pembayangan yang dihasilkan Pohon dan Bangunan di Koridor Jalan Perkotaan Untuk Mencapai Kenyamanan Termal

2018 ◽  
Vol 4 (1) ◽  
pp. 65-70
Author(s):  
Jockie Zudhy Fibrianto ◽  
Mochamad Hilmy
Keyword(s):  
Thermal Comfort ◽  
Temperature Difference ◽  
Weather Conditions ◽  
The Sun ◽  
The Road ◽  
Analysis Phase ◽  
Measurement Results ◽  
The Difference ◽  
Road Corridors ◽  
East West

The road corridor in Pontianak City has different shading output depending on the sun orientation. The difference has caused a temperature difference that affects the pedestrian thermal comfort along the corridor. Identification and measurement of shading temperatures that occur due to buildings and trees were carried out for three days in each afternoon with relatively similar weather conditions. The road corridor that becomes the research location was at A. Yani St.-Gajah Mada St.-Tanjung Pura St., which has a North-South orientation and Teuku Umar St.-Diponegoro St.-Sisingamangaraja St., who has an East-West direction. The analysis phase is done by comparing the effectiveness of imagery produced by buildings and trees. After that, the identification and measurement results are compared with Indonesian thermal comfort standards SNI T-14-1993-03 to obtain suitable thermal comfort in the road corridors in Pontianak City.

scholarly journals Thermal comfort of patients in hospital ward areas

1977 ◽  
Vol 78 (1) ◽  
pp. 17-26 ◽  
Author(s):  
R. M. Smith ◽  
A. Rae
Keyword(s):  
Steady State ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Hospital Ward ◽  
Patient Comfort ◽  
Mean Radiant Temperature ◽  
Air Velocity ◽  
Assessment Techniques ◽  
The Mean ◽  
Radiant Temperature

SUMMARYThe patient is identified as being of prime importance for comfort standards in hospital ward areas, other ward users being expected to adjust their dress to suit the conditions necessary for patient comfort. A study to identify the optimum steady state conditions for patient comfort is then described.Although this study raises some doubts as to the applicability of the standard thermal comfort assessment techniques to ward areas, it is felt that its results give a good indication of the steady-state conditions preferred by the patients. These were an air temperature of between 21.5° and 22° C and a relative humidity of between 30% and 70%, where the air velocity was less than 0.1 m/s and the mean radiant temperature was close to air temperature.

scholarly journals PENGARUH BUKAAN SAMPING (CLERESTORY) TERHADAP KUALITAS KENYAMANAN TERMAL PADA FOOD CARNIVAL, MALL AEON BSD

Vitruvian ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 47
Author(s):  
Tathia Edra Swasti
Keyword(s):  
Wind Speed ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Effective Temperature ◽  
Air Humidity ◽  
Air Velocity ◽  
Predicted Mean Vote ◽  
Air Speed ◽  
The Right

ABSTRAK Mall saat ini marak menggunakan clerestory sebagai salah satu upaya untuk penerangan alami pada siang hari. Namun, cahaya matahari pada sore hari (barat) akan menghasilkan cahaya matahari yang lebih panas dan silau dibandingkan cahaya matahari pada pagi hari (timur). Oleh karena itu, dengan pemakaian clerestory yang cukup besar pada bangunan, masalah panas tentu tak dapat dihindari. Begitu pula dengan glare yang berasal dari pantulan sinar matahari. Salah satu Mall yang menggunakan clerestory adalah Mall AEON BSD. Pengukuran suhu udara, temperatur efektif, kelembaban udara, kecepatan angin, PMV (Predicted Mean Vote) dan PPD (Predicted Percentage of Dissatisfied) dilaksanakan pada 4 waktu dengan 5 lokasi titik ukur yang memiliki kondisi berbeda untuk membuktikan bahwa clerestory dapat mempengaruhi kenyamanan termal. Disimpulkan bahwa titik 2 yaitu titik yang berdekatan dengan clerestory sisi kanan (ukurannya lebih kecil daripada clerestory sisi kiri) memiliki temperatur efektif dan kelembaban udara yang lebih rendah dari titik lain, dan kecepatan udara (dipengaruhi oleh hembusan AC) lebih tinggi dari titik lain. Responden merasa nyaman saat berada di titik tersebut.Titik paling nyaman menurut responden adalah titik 2 dengan TE rata-rata berkisar 27,4˚C, kelembaban udara rata-rata berkisar 52,2%, kecepatan udara rata-rata berkisar 0,15 m/s, PMV berkisar 0,5 dan PPD berkisar 12,7%. Dengan begitu semakin kecil ukuran skylight terbukti mempengaruhi kenyamanan termal dan membuat kenyamanan termal dapat tercapai. Kata Kunci: Mall, Clerestory, PMV, PPD, Kenyamanan Termal ABSTRACT Nowadays mall is decorated with clerestory as an effort to lighten naturally during the day. However, sunlight in the afternoon (west) will produce more sunlight and glare than sunlight in the morning (east). Therefore, with the use of a fairly large clerestory in buildings, the problem of heat certainly can not be avoided. Similarly, glare that comes from the reflection of sunlight. One of the malls that use clerestory is BSD AEON Mall. Measurement of air temperature, effective temperature, air humidity, wind speed, PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) carried out at 4 times within 5 measuring spots that have different conditions, proving that clerestory can affect thermal comfort. It was concluded that point 2, which is the point adjacent to the right side clerestory (smaller in size than the left side clerestory) has an effective temperature and lower air humidity than other points, and air velocity (affected by blowing AC) is higher than other points. Respondents felt comfortable when they were at that point. The most comfortable point according to respondents was point 2 with TE averaging around 27.4˚C, air humidity averaged 52.2%, the average air speed ranged from 0.15 m / s, PMV ranges from 0.5 and PPD ranges from 12.7%. Thus, the smaller size of the clerestory is affecting thermal comfort and thermal comfort can be achieved. Keywords: Mall, Clerestory, PMV, PPD, Thermal Comfort

On the Development of a Thermal Comfort Control for Classrooms Conditioned by Split-Type Systems

2019 ◽  
Author(s):  
Anastacio Silva Junior ◽  
Nathan Mendes ◽  
Rogério Vilain ◽  
Marcelo Pereira ◽  
Katia Cordeiro Mendonça
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Low Cost ◽  
Type System ◽  
Type Systems ◽  
General Purpose ◽  
Representative Point ◽  
Air Velocity ◽  
Comfort Index ◽  
Air Speed

Abstract Thermal comfort conditions may vary substantially within an air-conditioned room equipped by split-type systems. In this work, the comfort conditions in a classroom were evaluated experimentally based on the PMV index, according to ISO 7730 Standard that defines the thermal satisfaction in occupied environments. The experiment was carried out at three different supply airflows (high, medium and low) and three set-point temperatures (23, 24 and 25°C). The results showed that there is a considerable variation in the air velocity field in the room as well as in the PMV values for three different supply airflows, consequently significant changes of thermal comfort indices can be noticed. Several curves were adjusted aiming to express the values of PMV, deriving a simplified comfort index for rooms conditioned by split-type systems based on dry-bulb air temperature and air speed. The purpose of this adjustment is to obtain an equation that provides the value of the comfort index for cooling purposes. Thus, for a certain condition of use, one can predict what will be the value of PMV in an occupied environment, enabling the implementation of a control system of the comfort according to this new index (ICS). The variables considered in obtaining the curve were the air temperature (Tar) and the air velocity (Var), since these two variables can be controlled directly by the split-type system. The general purpose of this work is to provide experimental data for the development of a low-cost device to automatically control ICS-based thermal comfort in a space conditioned by a split-type system through a single and representative point within the classroom.

CFD-Based Parametric Analysis on the Performance of Personalized Partition Air Distribution Systems

Solar Energy ◽  
2006 ◽  
Author(s):  
Kybum Jeong ◽  
Moncef Krarti ◽  
Zhiqiang Zhai
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Distribution System ◽  
Distribution Systems ◽  
Comfort Level ◽  
Cfd Modeling ◽  
Air Distribution ◽  
Air Velocity ◽  
Comfort Index ◽  
System Mode

The partition air distribution systems evaluated in this study allow occupants to control the system mode (on/off) and the supply air velocity and direction with similar flexibility as occupants in automobiles. To find optimal specifications for the partition air distribution systems that are able to achieve comfortable micro-environment, a CFD modeling tool was used to simulate the airflow and thermal performance of the partition air distribution systems in a typical office space. By analyzing the distribution characteristics of indoor air temperature, air velocity and thermal comfort index, the study assessed the performance of the partition air distribution systems with different operating parameters. The simulation results were analyzed and evaluated to assess both occupant’s thermal comfort and system energy consumption. The study shows that space cooling energy can be reduced while maintaining acceptable indoor thermal comfort level using a partition air distribution system with a higher supply air temperature.

scholarly journals Thermal comfort, thermal sensation and skin temperature measurements using demand-controlled ventilation for individual cooling

2020 ◽  
Vol 172 ◽  
pp. 06001
Author(s):  
Håkon Solberg ◽  
Kari Thunshelle ◽  
Peter Schild
Keyword(s):  
Thermal Comfort ◽  
Skin Temperature ◽  
Energy Demand ◽  
Thermal Sensation ◽  
Air Velocity ◽  
Climate Chamber ◽  
Biometric Data ◽  
Ongoing Research ◽  
Demand Controlled Ventilation ◽  
The Relationship

An increasing part of modern building's energy demand is due to cooling. An ongoing research project investigates the possibility to reduce the energy consumption from cooling by utilizing an individually controlled active ventilation diffuser mounted in the ceiling. This study looks at thermal sensation and thermal comfort for 21 test persons exposed to an innovative user controlled active ventilation valve, in a steady and thermally uniform climate chamber. Furthermore, the relationship between biometric data from the test persons skin temperature and sweat, and the test persons thermal sensation scores has been investigated. Each test person was exposed to three different room temperatures in the climate chamber, 24°C, 26°C and 28°C respectively, to simulate typical hot summer conditions in an office in Norway. At a room temperature of 26°C it was possible to achieve acceptable thermal comfort for most test persons with this solution, but higher air velocity than 0.75 m/s around the test persons bodies at room temperatures of 28°C is required to ensure satisfactory thermal comfort.

Analysis of Natural Ventilation Systems in Schoolrooms

2016 ◽  
Vol 824 ◽  
pp. 625-632
Author(s):  
Mária Budiaková
Keyword(s):  
Mechanical Ventilation ◽  
Thermal Comfort ◽  
Energy Saving ◽  
Air Temperature ◽  
Natural Ventilation ◽  
Winter Period ◽  
Experimental Measurements ◽  
Air Velocity ◽  
The Future ◽  
Ventilation Systems

The paper is oriented on the analysis of the ventilation systems in schoolrooms. Correct and sufficient ventilation of schoolrooms is very important because students and pupils spend in the schoolrooms the majority of their time in school. In our schools the ventilation is incorrect and insufficient. The biggest problem is winter period when the ventilation is provided only by opening the doors to corridor. This way, there is insufficient intake of oxygen, which causes distractibility and feeling of tiredness of pupils. In current schoolrooms we can use only natural ventilation and thus the schoolrooms have to be ventilated using windows. Therefore this research was focused on the comparison and the analysis of different systems of natural ventilation in schoolrooms. The experimental measurements were carried out in schoolroom, where the parameters of thermal comfort were measured in the different systems of natural ventilation with device Testo 480 which was connected to computer. Gained values of air temperature, air velocity and index PMV are presented in graphs. On the base of analysis of measured values were evaluated the systems of natural ventilation for schoolrooms. In the future, the mechanical ventilation in schoolrooms can be assumed, therefore the recommendation on modern energy saving system of mechanical ventilation is in the end of this paper.

scholarly journals Thermal comfort and draught assessment in a modern open office building in Tallinn

2019 ◽  
Vol 111 ◽  
pp. 02013 ◽  
Author(s):  
Martin Kiil ◽  
Alo Mikola ◽  
Martin Thalfeldt ◽  
Jarek Kurnitski
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Energy Demand ◽  
Working Environment ◽  
Office Building ◽  
Indoor Climate ◽  
Air Velocity ◽  
Air Exchange Rate ◽  
Air Speed ◽  
Open Office

Modern office building users have high expectations about the working environment and thermal comfort, which requires the installation of complex technical systems such as combined cooling and ventilation. Room conditioning units of these systems must ensure temperature and ventilation control in a way that air velocity is low and the air temperature in acceptable range. Achieving air distribution avoiding draught is one of the key elements of a thermal comfort in modern office landscape. Higher air velocity in occupied zone is easily perceived as draught, which causes occupant dissatisfaction and complaints, as well as decrease in the productivity or effective floor space area. To reduce complaints, room air temperature setpoints or ventilation airflow rates are often modified, which may result in higher heating energy demand. In addition, excessive heating setpoint rise will not only consume more energy, but may cause health problems. Compared to cellular offices it is more difficult to ensure thermal comfort conditions in open office spaces where there are no walls for air flows. In addition, due to the higher number of employees it is more difficult to meet satisfactory conditions for everyone. The aim of this study was to evaluate thermal comfort parameters such as room air temperature, air speed and supply air temperature and how the users sense it in a modern office building in Tallinn, Estonia. Design room air temperature setpoints and air exchange rate were evaluated on open office spaces. Measured data with web-based indoor climate questionnaire was analysed. Results show which design and measured parameters make it possible to match the user comfort at all times.

Cooling with Box Fans

1982 ◽  
Vol 26 (2) ◽  
pp. 123-127
Author(s):  
Eric Rosen ◽  
Stephan Konz
Keyword(s):  
Thermal Comfort ◽  
Room Temperature ◽  
Thermal Sensation ◽  
Office Work ◽  
Air Velocity ◽  
Preferred Direction ◽  
The Subject ◽  
Paper And Pencil ◽  
C 78

Two experiments are described. Experiment 1 investigated the preferred direction of air upon a person. Forty males sat in front of a box fan in 12 different seating orientations (30° increments). Air velocity was .7 m/s (140 ft/min); room temperature was 28 C (82 F) with 40% rh. The preference was bimodal with the most preferred directions from the front or the rear; velocities from the side were less preferred. Experiment 2 investigated 3 velocities (“still air”, .8 m/s (160 ft/min) and 1.3 m/s (260 ft/min)) at 3 temperatures (25.6, 27.8 and 30 C; 78, 82, 86 F). Eight subjects each spent three hours in each of the 9 conditions. Clothing was standardized at about .5 clo. Subjects did a paper and pencil task (maze) and a peg into hole task. Thermal comfort and thermal sensation ballots were completed every 15 min. At the end of 150 min., they moved their chair in relation to the fan so as to select their preferred velocity. The current recommended ceiling of .8 m/s for sedentary office work is too low as the subject-selected velocity was .7 m/s at 25.6 C, was 1.0 m/s at 27.8 C and was 1.2 m/s at 30 C. These results were confirmed by the thermal comfort and thermal sensation ballots. Depending on the criterion used, for seated sedentary work in warm conditions, every 0.1 m/s (20 ft/min) increase in air velocity offsets approximately a 0.4 C (0.7 F) increase in temperature (0.7 < V < 1.2 m/s).

scholarly journals Enhancement of Thermal Comfort Inside the Kitchen of Non-Airconditioned Railway Pantry Car

2021 ◽  
Vol 39 (1) ◽  
pp. 275-291
Author(s):  
Md Sarfaraz Alam ◽  
Urmi Ravindra Salve
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Ventilation System ◽  
Comfort Level ◽  
Air Velocity ◽  
Sustainable Improvement ◽  
Study Results ◽  
Air Ventilation

There are ample literature studies available, focusing on hot-humid built environment, which have achieved an increase in thermal comfort conditions by proper installation of ventilation-systems. The present thermal comfort study has been carried out in the kitchen environment of a non-air-conditioned railway pantry car in Indian Railways. The purpose is to enhance thermal comfort level under the currently applied ventilation system inside the kitchen of pantry car by determining the standard effective temperature (SET) index. During the summer and winter seasons, a field study was carried out to obtain the value of air temperature, globe temperature, relative humidity, and air velocity inside the pantry car for estimation of the SET index. A computational fluid dynamics (CFD) analysis was used to obtain a better-modified case model of the pantry car kitchen for the improvement of thermal comfort. The design interventions for the pantry car kitchen were created, with emphasis on increasing energy efficiency based on low-power consumption air ventilation system. The study results indicated that, modified case-I model has a better ventilation design concept as compare to the existing and other models, which increased the air velocity and significantly decreased the air temperature inside the kitchen of pantry car at all cooking periods. A value of SET (28.6–30℃) was found with a comfortable thermal sensation within all cooking periods, which is better for the pantry car workers. This finding suggests a sustainable improvement in the thermal environment of the "non-air-conditioned" pantry car kitchen in the Indian Railways, which can be applied immediately.

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