scholarly journals A Numerical Study on Indoor Air Quality (IAQ) Designs for Hospital Waiting Room in The Context of COVID-19 For Hot and Warm Humidity Climate

2021 ◽  
Vol 2071 (1) ◽  
pp. 012056
Author(s):  
M N Rahman Y ◽  
Z M Razlan ◽  
M Nazrin Y ◽  
N A A Razali ◽  
M I Izham ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Thermal Comfort ◽  
Numerical Study ◽  
Ventilation System ◽  
Waiting Room ◽  
Ansys Fluent ◽  
Indoor Space ◽  
Average Temperature ◽  
Lecture Room ◽  
Difficulty Breathing

Abstract COVID-19 is a virus originated from Corona Virus which can severe acute respiratory syndrome (SARS) symptoms such as chest pain, dry cough, fever, and difficulty breathing. The AC and ventilation system is not only important for the thermal comfort occupants but to ensure the room is safe and free from infectious virus. Thermal comfort is important measurement in indoor space which influenced by temperature, Relative Humidity (RH), airflow velocity and others. This research was executed and focused on lecture room in Bilik Persatuan 10, Universiti Malaysia Perlis (UniMAP) instead of real hospital waiting room. It comes with the room dimensions 11.87m (Length) × 5.17m (Width) × 2.93m (Height) for the numerical study. In addition, Computational Fluid Dynamics (CFD) analysis is used to investigate the air flow pattern and temperature distribution inside the room. By using software Ansys FLUENT 19, field experimental and simulation work can be compared which have 14.55% difference in temperature distribution. It is expected by increasing the air velocity of the AC inlet diffuser influence the pattern of airflow in the room, but average temperature remains same for all these conditions.

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 Study on Hot Gases Flow in Case of Fire in a Road Tunnel

2018 ◽  
Author(s):  
Aleksander Król ◽  
Małgorzata Król
Keyword(s):  
Temperature Distribution ◽  
Initial Phase ◽  
Ventilation System ◽  
Main Axis ◽  
Road Tunnel ◽  
Ansys Fluent ◽  
The Road ◽  
Longitudinal Ventilation ◽  
Australian Standard ◽  
Recorded Data

This paper presents the results of hot smoke tests, conducted in a real road tunnel. The tunnel is located within the expressway S69 in southern Poland between cities Żywiec and Zwardoń. Its common name is Laliki tunnel. It is a bi-directional non-urban tunnel. The length of the tunnel is 678 m and it is inclined by 4%. It is equipped with the longitudinal ventilation system. Two hot smoke tests have been carried out according to Australian Standard AS 4391-1999. Hot smoke tests corresponded to a HRR (Heat Release Rate) equal to respectively 750 kW and 1500 kW. The fire source was located in the middle of the road lane imitating an initial phase of a car fire (respectively 150 m and 265 m from S portal). The temperature distribution was recorded during both tests using a set of fourteen thermocouples mounted at two stand poles located at the main axis of the tunnel on windward. The stand poles were placed at distances of 5 m and 10 m. The recorded data were applied to validate of a numerical model built and solved using Ansys Fluent. The calculated temperature distribution matched the measured values.

scholarly journals Power Substation Construction and Ventilation System Co-Designed Using Particle Swarm Optimization

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2314
Author(s):  
Jau-Woei Perng ◽  
Yi-Chang Kuo ◽  
Yao-Tsung Chang ◽  
Hsi-Hsiang Chang
Keyword(s):  
Numerical Study ◽  
Ventilation System ◽  
Particle Swarm ◽  
Information Modeling ◽  
Particle Swarm Optimizer ◽  
Ansys Fluent ◽  
Power Substation ◽  
Building Information ◽  
Building Ventilation ◽  
Ventilation Performance

This study discusses a numerical study that was developed to optimize the ventilation system in a power substation prior to its installation. We established a multiobjective particle swarm optimizer to identify the best approach for simultaneously improving, first, the ventilation performance considering the most appropriate inlet size and outlet openings and second, the reduction of the synthetic noise of the ventilation and power consumption from the exhaust fan equipment and its operation. The study used building information modeling to construct indoor and outdoor models of the substation building and verified the overall performance using ANSYS FLUENT 18.0 software to simulate the air velocity and air temperature distribution within the building. Results show that the exhaust fan of the B1F cable finishing room and the 23 kV gas insulated switchgear (GIS) room optimize the reduction of horsepower by approximately 1 Hp and 0.5 Hp. The combined noise is reduced by 4 dBA and 2 dBA; the exhaust fan runs for 30 min, and the two equipment rooms can cool down by 2.9 °C and 1.7 °C, respectively. Therefore, it is confirmed that the MOPSO algorithm provides a more energy-efficient and environmentally friendly building ventilation environment.

Evaluation of comfort levels in office space equipped with HVAC system based in personalized ventilation system using energy produced in DSF systems

2020 ◽  
pp. 65-74
Author(s):  
Eusébio Conceição ◽  
Mª Inês Conceição ◽  
Mª Manuela Lúcio ◽  
João Gomes ◽  
Hazim Awbi
Keyword(s):  
Air Quality ◽  
Numerical Model ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Numerical Study ◽  
Ventilation System ◽  
Airflow Rate ◽  
Hvac System ◽  
Personalized Ventilation

In this study the numerical simulation of a Heating, Ventilating and Air Conditioning (HVAC) system, based in a personalized ventilation system, installed in an occupied office desk is made. The energy is produced in a Dual Skin Facades (DSF) system installed in the outdoor environment. The personalized ventilation system, placed above and below the writing area, installed in the desk central area. The office desk is occupied by eight virtual manikins. The numerical simulation is made in a winter typical day. This numerical study considers a coupling of a differential numerical model and an integral numerical model. The differential numerical model simulates the Computational Fluids Dynamics (CFD), evaluates the air velocity, air temperature, turbulence intensity and carbon dioxide concentration and calculates the indoor air quality. The integral numerical model simulates the Multi-Node Human Thermo-physiology Model, evaluates the tissue, blood and clothing temperatures distribution and calculates the thermal comfort level. The HVAC system, based on a DSF system, is built using three DSF unities, is equipped with internal venetian blinds. Each one, installed in a virtual chamber, is turned to south. The personalized ventilation system, made with eight upper and eight lower air terminal devices, is installed in the desk central area. On each table top two upper and two lower air terminal devices are considered in the left and right manikin area, while on each side of the table two upper and two lower air terminal devices are placed between the manikins. The office desk is occupied by eight virtual manikins, one sitting on each table top and three sitting on each side of the meeting table. In this numerical study, carried out in winter conditions, the occupants’ clothing level is 1 clo. In these situations a typical activity level of 1.2 met is considered. The evolution of indoor environmental conditions, in the DSF and in the office room, are calculated during a full winter typical day. The thermal comfort, the indoor air quality, the effectiveness for heat removal, the effectiveness for contaminant removal and the Air Distribution Index (ADI), are evaluated. In accordance with the obtained results the thermal comfort levels increase when the air renovation rate increases and the indoor air quality level increases when the air renovation rate increases. However, the ADI is quite constant when the inlet airflow rate increases, because the thermal comfort number decreases when the inlet airflow rate increases and the air quality number increases when the inlet airflow rate increases.

scholarly journals EXPERIMENTAL INVESTIGATION AND CFD SIMULATION OF INDOOR AIR QUALITY IN ROOM USING IMPINGING JET VENTILATION SYSTEM AT DIFFERENT OCCUPANT DISTRIBUTION

2021 ◽  
Vol 21 (2) ◽  
pp. 130-147
Author(s):  
Ala'a Abbas Mahdi ◽  
Sara Mohammed Abbas
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Numerical Study ◽  
Ventilation System ◽  
Experimental Studies ◽  
Impinging Jet ◽  
The Other ◽  
Jet Ventilation ◽  
Analysis And Design ◽  
Human Thermal Comfort

The current paper reports the analysis and design of air quality and human thermal comfort in rooms using impinging jet ventilation system at different occupant distribution. Theoretical and experimental studies at different situations of occupant distribution used the square cross sectional supply air duct with height from the foot level end (0.1h). This work presents a numerical study for predicting the indoor airflow and temperature distribution by adopting impinging jet ventilation system in office room. The emergence of the three zones flow field of an impinging jet is mostly divided into three distinguished zones: impingement zone, wall jet zone and free jet zone which produce excessive kinetic energy at the stagnation zone and distribute approximately in the longitudinal and lateral directions over the floor. Acceptable Air Distribution Performance Index (ADPI), effective temperature and ventilation efficiency were found at situations of occupant distribution (when the occupant located at the center of the room one sitting in front of the other gives optimum human thermal comfort if compared with the other situations of occupant distributions).

scholarly journals THERMAL COMFORT STUDY OF TEACHERS' ROOM AT SEKOLAH BINA MULIA PONTIANAK

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Albert Suryajaya ◽  
Tri Wibowo Caesariadi
Keyword(s):  
Mechanical Ventilation ◽  
Thermal Comfort ◽  
Building Materials ◽  
Ventilation System ◽  
Neutral Condition ◽  
Average Value ◽  
Average Temperature ◽  
Wind Circulation ◽  
Air Ventilation ◽  
Comfort Condition

Thermal comfort is one of the important aspects to ensure the comfort of a building. School building, e.g. Sekolah Bina Mulia, Pontianak is used for education activities for about eight hours a day. The teachersfourth floor and still applies the natural air ventilation system while other rooms use mechanical ventilation system. It is interesting to see thermal comfort condition in the ort of the room depends on the environment. Because of its position on the fourth floor, the wind circulation can flow freely and the application of air ventilation is possible. The average temperature is 29.599ºC, 71.216% for relative humidity and 0.143 m/s for wind speed, and 29.482ºC for MRT. The average value of PMV is 1.615. The thermal comfort value, based on the average of PPS*(PMV) calculation for three days observation is 0.130 and it is the neutral condition. This means the room is comfort for the users and it is mainly because  of the windows, sun shading, and the building materials which support the natural air ventilation of the school Kenyamanan termal merupakan salah satu aspek penting untuk memastikan suatu bangunan dapat memberikan kenyamanan bagi penggunanya. Bangunan sekolah, seperti Sekolah Bina Mulia Pontianak merupakan bangunan pendidikan yang digunakan kurang lebih delapan jam dalam satu hari. Ruang guru pada sekolah Bina Mulia, yang terletak pada lantai empat masih menggunakan sistem ventilasi udara alami sementara ruangan lain menggunakan sistem penghawaan mekanikal. Kenyamanan termal pada ruangan tentu sangat tergantung pada Keadaan lingkungan. Karena posisinya yang cukup tinggi, pergerakan udara pada ruangan juga lebih bebas. Artinya, aplikasi ventilasi udara alami sangat memungkinkan. Nilai temperatur udara rata-rata pada ruangan adalah 29,599 ºC, kelembaban 71,216%, kecepatan udara 0,143 m/det dan nilai temperatur radiasi 29,482ºC. Nilai PMV rata-rata pada ruangan adalah 1,615. Nilai PPS*(PMV) rata-rata pada ruangan tersebut dalam tiga hari pengamatan adalah 0,130 dan merupakan kondisi netral. Ini artinya ruangan tersebut nyaman bagi penggunanya, yang pada dasarnya dikarenakan sistem jendela, pelindung matahari, dan material bangunan dapat mendukung ventilasi udara alami pada bangunan

scholarly journals An Investigation of the Effect of Ventilation Inlet and Outlet Arrangement on Heat Concentration in a Ship Engine Room

2017 ◽  
Vol 7 (5) ◽  
pp. 1996-2004
Author(s):  
E. Alizadeh ◽  
A. Maleki ◽  
Α. Mohamadi
Keyword(s):  
Temperature Distribution ◽  
Distribution Pattern ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Temperature Level ◽  
Average Temperature ◽  
Air Inlet ◽  
Engine Room ◽  
Air Volume ◽  
Main Engine

Τhe ventilation in the ship engine rooms is an essential issue concerning finest performance of engines and diesel generators as well as electric motors. The present study has aimed at the analysis of temperature distribution inside the ship main engine room. In the same way, attempts have been made to identify those points with considerable thermal concentration in main engine room space, so that proper ventilation systems could be engineered and utilized and favorable thermal conditions could be realized. The CFD approach has been utilized in order to analyze impact of the designed ventilation system on the temperature distribution pattern. The Inlet layout and area have been analyzed under a variety of scenarios in order to decrease the average temperature and eliminate the heat concentrations in various points of the engine room. The temperature distribution and location and area of ventilation air inlet have been studied in different modes resulted in temperature distribution pattern, heat concentration outline and average volumetric temperature level in each mode. The results indicated that considerable circulating air volume is required compared to those levels suggested by common practices, calculations and standards in order to eliminate the heat concentration.

Numerical and Experimental Modeling of Indoor Air Quality Inside a Conditioned Space with Mechanical Ventilation and DX-Air Conditioner

2020 ◽  
Vol 38 (9A) ◽  
pp. 1257-1275
Author(s):  
Wisam M. Mareed ◽  
Hasanen M. Hussen
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Airflow Rate ◽  
Air Conditioner ◽  
Breathing Zone ◽  
Lecture Room ◽  
Ventilation Performance

 Elevated CO2 rates in a building affect the health of the occupant. This paper deals with an experimental and numerical analysis conducted in a full-scale test room located in the Department of Mechanical Engineering at the University of Technology. The experiments and CFD were conducted for analyzing ventilation performance. It is a study on the effect of the discharge airflow rate of the ceiling type air-conditioner on ventilation performance in the lecture room with the mixing ventilation. Most obtained findings show that database and questionnaires analyzed prefer heights between 0.2 m to 1.2 m in the middle of an occupied zone and breathing zone height of between 0.75 m to 1.8 given in the literature surveyed. It is noticed the mismatch of internal conditions with thermal comfort, and indoor air quality recommended by [ASHRAE Standard 62, ANSI / ASHRAE Standard 55-2010]. CFD simulations have been carried to provide insights on the indoor air quality and comfort conditions throughout the classroom. Particle concentrations, thermal conditions, and modified ventilation system solutions are reported.

An Investigation of the Effect of interrupted fin arrangements on the Thermal Performance of a Heat Sink under a Free Convection Condition

2019 ◽  
Vol 7 (1) ◽  
pp. 43-53
Author(s):  
Abbas Jassem Jubear ◽  
Ali Hameed Abd
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Numerical Study ◽  
Ansys Fluent ◽  
Fluent Software ◽  
Steady State Heat ◽  
Steady State Heat Transfer

The heat sink with vertically rectangular interrupted fins was investigated numerically in a natural convection field, with steady-state heat transfer. A numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model.  The dimensions of the fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins. The number of fins used on the surface is eight. In this study, the heat input was used as follows: 20, 40, 60, 80, 100, and 120 watts. This study focused on interrupted rectangular fins with a different arrangement and angle of the fins. Results show that the addition of interruption in fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate as an equation can be obtained.

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