ASSESSMENT OF AIR CHANGE EFFECTIVENESS AND THERMAL COMFORT IN A NATURALLY VENTILATED KITCHEN WITH INSECT-PROOF SCREEN USING CFD

2021 ◽  
Vol 16 (3) ◽  
pp. 37-56
Author(s):  
T K Jayasree ◽  
B S Jinshah ◽  
V Lakshmi Visakha ◽  
Tadepalli Srinivas
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
The Other ◽  
Air Velocity ◽  
Ansys Fluent ◽  
Thermal Discomfort ◽  
Ventilation Efficiency ◽  
Warm Sensation ◽  
The Mean ◽  
Real Scenario

ABSTRACT Many dwellings in warm-humid climates attain a comfortable environment by natural ventilation. The opening of exterior windows for ventilation allows the entry of insects along with the breeze. As a remedy, occupants install insect-proof screens on windows resulting in reduced airflow into the interior. This study attempts to evaluate the air change effectiveness and thermal comfort in a residential kitchen with insect-proof screens. A kitchen with insect-proof screens on the windows is compared with a case without insect-proof screens. Numerical simulation was conducted using ANSYS Fluent 2019 R2. The insect-proof screen is modelled as a porous media. The air velocity and temperature measurements were validated by measurements in a real scenario. The presence of insect-proof screens reduced the air velocity inside the space by 82%. However, the airflow pattern in the case with screens was more uniformly distributed. The mean age of the air was considerably higher in the case with insect-proof screens, which in turn resulted in a reduced ACE. The presence of an insect-proof screen resulted in a Predicted Mean Vote (PMV) of 2.79 indicating a ‘hot’ sensation, whereas in the other case, the comfort vote is only 1.93 indicating a ‘warm’ sensation. The presence of insect-proof screens on windows reduced the air velocity and ventilation efficiency, contributing to increased thermal discomfort in the kitchen.

scholarly journals An Air Terminal Device with a Changing Geometry to Improve Indoor Air Quality for VAV Ventilation Systems

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4947
Author(s):  
Nina Szczepanik-Scislo ◽  
Jacek Schnotale
Keyword(s):  
Thermal Comfort ◽  
Ventilation System ◽  
Ansys Fluent ◽  
Variable Air Volume ◽  
Terminal Device ◽  
Air Volume ◽  
Air Supply ◽  
Volume Ventilation ◽  
Ventilation Efficiency ◽  
Comfort Parameters

This study aimed to develop a new concept for an air terminal device for a VAV (variable air volume) ventilation system that would improve overall ventilation efficiency under a varying air supply volume. In VAV systems, air volume is modified according to the thermal load in each ventilated zone. However, lowering the airflow may cause a lack of proper air distribution and lead to the degradation of hygienic conditions. To combat this phenomenon, an air terminal device with an adapting geometry to stabilize the air throw, such that it remains constant despite the changing air volume supplied through the ventilation system, was designed and studied. Simulations that were performed using the RNG k–ε model in the ANSYS Fluent application were later validated on a laboratory stand. The results of the study show that, when using the newly proposed terminal device with an adaptive geometry, it is possible to stabilize the air throw. The thermal comfort parameters such as the PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) proved that thermal comfort was maintained in a person-occupied area regardless of changing airflow though the ventilation system.

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 Evaluating the Perception of Ventilation for Thermal Comfort in Senate Buildings: A Case of Nigeria Universities

2018 ◽  
Vol 9 (1) ◽  
pp. 1-9
Author(s):  
Ayeni Conqueror A. ◽  
Ayinla A. Kunle ◽  
Ajayi Oluwole
Keyword(s):  
Thermal Comfort ◽  
Direct Observation ◽  
Natural Ventilation ◽  
Physical Characteristics ◽  
Office Buildings ◽  
Thermal Discomfort ◽  
South West ◽  
Survey Results ◽  
Major Factors ◽  
Window Condition

Window condition is one of the major factors of ventilation in office buildings. The study aimed at evaluating the natural ventilation in Senate buildings of selected Universities in South-West Nigeria. The study employed the use of questionnaires survey to solicit information on subjective feelings of the occupants on the effects of thermal opening and thermal comfort in Senate buildings offices. Direct observation was carried out to obtain information on the physical characteristics of the selected buildings. Limited research has been recorded on the study of occupants’ feelings in buildings in relation to openings in buildings. Based on the survey results, it was found that 34.0% of the windows were casement type, 30.0 % were projected 25.5% were sliding; while 9.5% were the louvred type. The study showed that 73.8% of the respondents preferred the casement window type because of its easiness in operation to other window types and improved thermal comfort on occupants. The study concluded that with adequate sizes, casement window type is the best in ameliorating the effect of thermal discomfort in Senate Buildings.  

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.

A numerical investigation on the impacts of voids combinations on natural ventilation of high-rise residential building

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamza Laloui ◽  
Noor Hanita Abdul Majid ◽  
Aliyah Nur Zafirah Sanusi
Keyword(s):  
Thermal Comfort ◽  
Indoor Air ◽  
Design Methodology ◽  
Natural Ventilation ◽  
Residential Building ◽  
Air Velocity ◽  
Content Type ◽  
High Rise ◽  
Living Unit ◽  
Ventilation Performance

Purpose This paper aims to investigate the impacts of introducing voids combinations on natural ventilation performance in high-rise residential building living unit. Design/methodology/approach This study was carried out through field measurement and computational fluid dynamics methods. The parameters of the study are void types and sizes, and a wind angle was used to formulate case studies. Findings The results indicate that the provision of a single-sided horizontal void larger by 50% increase the indoor air velocity performance up to 322.37% to 0.471 m/s in the living unit and achieves the required velocity for thermal comfort. Originality/value Passive design features are the most desirable techniques to enhance natural ventilation performance in the high-rise residential apartments for thermal comfort and indoor air quality purposes.

scholarly journals An indoor environment evaluation by gender and age using an advanced personalized ventilation system

2017 ◽  
Vol 38 (5) ◽  
pp. 505-521 ◽  
Author(s):  
Ferenc Kalmár
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Side Effect ◽  
Thermal Sensation ◽  
Ventilation System ◽  
The Other ◽  
Air Velocity ◽  
Personalized Ventilation

In a closed space, appropriate thermal comfort and proper indoor air quality are extremely important in order to obtain the optimal work performance and to avoid health problems of the occupants. Using advanced personalized ventilation systems, different comfort needs can be locally satisfied even in case of warm environments. Thermal sensation and the subjective evaluation of indoor air quality of young and elderly people, men and women respectively, were studied in warm environment using advanced personalized ventilation system combined with total volume ventilation system. Using an advanced personalized ventilation system, 20 m3 h−1 air flow was alternately introduced by three air terminal devices built-in the desk and placed on a horizontal plane at the head level of the sitting subject. Thermal sensation was significantly cooler in case of young women in comparison with the other groups. Odor intensity was evaluated to be significantly lower in case of elderly women in comparison with the other groups. Evaluation of air freshness is in correlation with the general thermal sensation. Variation of the direction of the air velocity vector has a cooling side-effect, which, in warm environments, might be useful in order to improve the thermal comfort sensation. Practical application: From the basic factors that influence the thermal comfort sensation, air velocity is the one and only parameter that must be treated as a vector. The air flow velocity has an important effect on the convective heat quantity released by the human body, but the changes in the air velocity direction have a cooling side-effect. This cooling side-effect should be exploited properly in warm environments by advanced personalized ventilation systems to improve the thermal comfort sensation of the occupants without supplementary energy use.

The Impact of Hybrid Ventilation on Thermal and Energy Performance in Hot and Humid Weather

2011 ◽  
Vol 199-200 ◽  
pp. 1505-1508
Author(s):  
Jia Fang Song
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Energy Performance ◽  
Simulation Software ◽  
Comfort Level ◽  
Air Velocity ◽  
Output Performance ◽  
Hybrid Ventilation ◽  
The Impact ◽  
Full Height

In this paper, the simulation software was applied to evaluate a hybrid ventilated combined mechanical and naturally ventilated (atrium area to be naturally ventilated) building. In order to understand the impact of the usage of natural ventilation on thermal comfort in atrium, we utilized TAS to simulate the air temperature and air velocity distribution for the atrium. A modeled three-storey commercial office building was used as the main subject of this analysis. To determine the thermal comfort level of the central atrium, Parameters will be set in such a way that the full height windows will be 100% open. Results were tabularized to determine and analysis the output of the simulation. Recommendations will be then given based on the output performance of the building.

scholarly journals Determination of thermal and acoustic comfort inside a vehicle’s cabin

2018 ◽  
Vol 32 ◽  
pp. 01002
Author(s):  
Alexandra Ene ◽  
Tiberiu Catalina ◽  
Andreea Vartires
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
The Other ◽  
Air Velocity ◽  
Acoustic Comfort ◽  
Comfort Parameters

Thermal and acoustic comfort, inside a vehicle’s cabin, are highly interconnected and can greatly influence the health of the passengers. On one hand, the H.V.A.C. system brings the interior air parameters to a comfortable value while on the other hand, it is the main source of noise. It is an intriguing task to find a balance between the two. In this paper, several types of air diffusers were used in order to optimize the ratio between thermal and acoustic interior comfort. Using complex measurements of noise and thermal comfort parameters we have determined for each type of air diffuser the sound pressure level and its impact on air temperature and air velocity.

scholarly journals Numerical evaluation of thermal discomfort in conditions of surface heating and asymmetric radiation

2018 ◽  
Vol 9 (2) ◽  
pp. 175-179
Author(s):  
F. Kalmár ◽  
T. Kalmár
Keyword(s):  
Thermal Properties ◽  
Thermal Comfort ◽  
Winter Period ◽  
Negative Effects ◽  
Air Velocity ◽  
Thermal Discomfort ◽  
External Wall ◽  
Wall Heating ◽  
Personalized Ventilation ◽  
Radiant Temperature

This paper presents the results of analytical analysis of thermal comfort and radiation asymmetry in case of wall heating depending on the room geometry and thermal properties of the external wall. The negative effects of radiation asymmetry on thermal comfort in case of summer conditions can be lowered using advanced personalized ventilation systems. In case of buildings with poor thermal properties of the envelope during the winter period low surface temperatures may occur. The aim of this research was to analyse the thermal asymmetry in the case of a room with one external wall and wall heating installed on the opposite wall. It was assumed that the radiation asymmetry will lead to discomfort and it was hypothesised that the discomfort might be reduced increasing the air velocity. The results have proven that thermal asymmetry in the middle of the room will not lead to thermal discomfort even for walls without any additional thermal insulation. However, the mean radiant temperature varies significantly depending on the position of the occupant in the room. In this case, the personalized control on the air velocity can help to improve the thermal comfort conditions.

The Study of Thermal Comfort and Noise Level in Battery Plate Factory

2014 ◽  
Vol 663 ◽  
pp. 474-479
Author(s):  
Mohd Anas Mohd Sabri ◽  
Mohd Faizal Mat Tahir ◽  
Kamaruzaman Sopian ◽  
Muhammad Hadi Zabidi Rosdi
Keyword(s):  
Relative Humidity ◽  
Metabolic Rate ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Noise Level ◽  
Comfort Level ◽  
The Other ◽  
Air Velocity ◽  
Other Hand ◽  
Radiant Temperature

The successful of manufacturing factories in industry is highly dependent on a productivity of their employees especially operators. It was identified that comfort and noise level can reduce the productivity of their workers. This study is to determine the level of thermal and noise comfort in the battery plate factory. This study was conducted in three days and location of the study is at battery plate factory in Semenyih, Selangor, Malaysia. The scope of study is focused at plate manufacturing area where the employee estimated 40 persons. The thermal comfort level can be determined by calculating PMV and PPD. This study involved six factors of comfort which is air temperature, average radiant temperature, air velocity, relative humidity, metabolic rate and clothes insulation. Then the study of noise level was conducted by determining LAeq, T, Lmax and Lmin. To carry out this study, Babuc-A equipment were used. The analysis show the area of the manufacturing battery plate having a discomfort condition and PMV result is between 1.5 until 3. Air temperature on the other hand is between 27.4°C-37.8°C while relative humidity is between range 35.35% -92.1% and air velocity 0 m/s-1.28 m/s. Meanwhile the LAeq,T value in the factory is varied from 68 to 80 dB.

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