scholarly journals ANALYSIS OF AIR FLOW DISTRIBUTION IN RESIDENTIAL ROOMS WITH SUPPLY WINDOW VALVES BY MATHEMATICAL MODELING IN ANSYS FLUENT

2019 ◽  
Vol 4 (10) ◽  
pp. 67-73
Author(s):  
О. Симбирев ◽  
O. Simbirev
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Natural Ventilation ◽  
Residential Buildings ◽  
Ventilation System ◽  
Flow Distribution ◽  
Ansys Fluent ◽  
Airflow Distribution ◽  
Standard Values ◽  
Technical Solutions

The main problem highlighted in the article is the deviation of the microclimate parameters from the standard values due to the improper organization of airflow in the residential rooms of apartment buildings. The objective is to obtain a working mathematical model of the natural ventilation system, its study for optimization or modernization. The analysis of the normative literature, scientific works of domestic and foreign scientists, developments in the field of natural ventilation and ventilation of residential buildings is carried out. A mathematical model of air exchange of a residential room with convection is presented and analyzed. The flow rate and air temperature, the temperature on the surface of the heater are set as boundary conditions when creating a mathematical model. The features and regularities of airflow distribution in the room obtained as a result of mathematical modeling are revealed. The distributions of air velocity in the room are given. Difficulties of the organization of effective natural inflow of air and the problems with design of valves of infiltration are designated. Technical solutions aimed at improving the quality of indoor microclimate and energy saving are proposed.

scholarly journals Living quarters. A natural balanced ventilation system. Simulations part 1

2018 ◽  
Vol 49 ◽  
pp. 00025 ◽  
Author(s):  
Tomasz Gaczoł
Keyword(s):  
Natural Ventilation ◽  
Residential Buildings ◽  
Ventilation System ◽  
Comfort Level ◽  
Test Results ◽  
Pressure System ◽  
Ansys Fluent ◽  
Short Supply ◽  
Air Exchange Rate ◽  
Exhaust Duct

In the following article the author proposes the solution for a properly functioning natural ventilation system based on the use of supply and exhaust ducts, i.e. by designing a natural balanced ventilation system. The paper is devoted to test results of air flow through natural ventilation supply-exhaust ducts in the rooms located on the lower floor of the building. The simulations conducted in ANSYS Fluent software relate to such issues as: pressure system inside the room and in the exhaust duct, distribution of air temperatures in the room, vector direction of airflow through supplyexhaust ducts and in the analysed room. Three types of solutions were selected for the tests: air inflow into the room through the air intake located at the basement level, air inflow through the window ventilator (although no longer used, this solution can be found in many existing residential buildings) and the natural ventilation system supported with the so-called “solar chimney”. All simulations were conducted with an outdoor temperature of +3 degrees C. The indoor temperature is + 20 degrees C, considered to be the minimum thermal comfort level. In the era of common building sealing, the presented ventilation system may be a good solution that guarantees proper functioning of natural ventilation. In all cases presented, it meets the normative regulations and requirements for the ventilation air stream and the air exchange rate in the room. The paper (first part) describes test results concerning the room located on the lower floor of the building, i.e. with a short supply duct and a 12-meter long exhaust duct.

scholarly journals Three-Dimensional Simulation of Wind-Driven Ventilation Through a Windcatcher With Different Inlet Designs

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. Phuoc Huynh
Keyword(s):  
Wind Speed ◽  
Average Velocity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Ansys Fluent ◽  
Wind Velocities ◽  
Dimensional Simulation ◽  
Convergent Inlet

Abstract Windcatcher is an effective natural ventilation system, and its performance depends on several factors including wind speed and wind direction. It provides a comfortable and healthy indoor environment since the introduced fresh air decreases the moisture content and reduces the pollutant concentration. Since the wind speed and its direction are generally unpredictable, it is important to use special inlet forms and exits to increase the efficiency of a windcatcher. In this study, computational fluid dynamics (CFD) modeling is implemented using ansys fluent to investigate the airflow entering a three-dimensional room through a windcatcher with different inlet designs. Three designs are studied which are a uniform inlet, a divergent inlet, and a bulging-convergent inlet. The airflow pattern with all inlets provided adequate ventilation through the room. With all the applied wind velocities (1, 2, 3, and 6 m/s) at the domain's inlet, the divergent inlet shape has captured the highest airflow through the room and provided higher average velocity at 1.2 m high enhancing the thermal comfort where most of the human occupancy occurs. With 6 m/s wind velocity, the divergent inlet has captured 2.55% more flow rate compared to the uniform inlet and 4.70% compared to the bulging-convergent inlet, and it has also provided an average velocity at 1.2 m high in the room of 7.16% higher than the uniform inlet and 8.44% higher than the bulging-convergent inlet.

scholarly journals Optimizing air velocity for the underfloor forced ventilation to protect a refrigerated warehouse from frost heaving

2018 ◽  
Vol 38 (3) ◽  
pp. 321-327
Author(s):  
Jingfu Jia ◽  
Manjin Hao ◽  
Jianhua Zhao
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Frost Heave ◽  
Forced Ventilation ◽  
Air Velocity ◽  
Set Up

Forced or natural ventilation is the most common measure of frost heave protection for refrigerated warehouse floor. To optimize air velocity for the underfloor forced ventilation system of refrigerated warehouse, a steady state three-dimensional mathematical model of heat transfer is set up in this paper. The temperature fields of this system are simulated and calculated by CFD software PHOENICS under different air velocity, 1.5m/s, 2.5m/s or 3.5m/s. The results show that the optimized air velocity is 1.5m/s when the tube spacing is 1.5m.

scholarly journals Determination of the speed of air outflow from the ventilation shaft of the warm attic of a multi-storey residential building under different initial conditions

2021 ◽  
Vol 18 (5) ◽  
pp. 126-129
Author(s):  
E. A. Anshukova ◽  
Keyword(s):  
Mathematical Modeling ◽  
System Performance ◽  
Natural Ventilation ◽  
Initial Conditions ◽  
Ventilation System ◽  
Residential Building ◽  
Operating Conditions ◽  
Ventilation Shaft

The operating conditions of a warm attic as an element of natural ventilation of a multi-storey residential building have an impact on the efficiency of the entire ventilation system performance, as well as on the condition of the enclosing structures. The study of the distribution of microclimate parameters in its volume makes it possible to more fully assess the ongoing processes. The result of calculating the rate of air outflow from the ventilation shaft of a warm attic by mathematical modeling is provided.

scholarly journals Evaluation of Thermal Comfort in the Traditional Bourgeoisie Houses in Beirut

2020 ◽  
Vol 3 (1) ◽  
pp. p1
Author(s):  
Jad Hammoud ◽  
Elise Abi Rached
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Heat Waves ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Residential Buildings ◽  
Ventilation System ◽  
Electricity Consumption ◽  
Comfort Level ◽  
Climate Zones

The increasing of energy demands has considerably increased the requirements for new and traditional buildings in different climate zones. Unprecedented heat waves have increased climate temperature, in particular, in moderate climate zones such as Lebanon. In Beirut, only the residential sector consumes 50% of total electricity consumption. HVAC (Heating, Ventilation and Air conditioning) systems are used to reach acceptable thermal comfort levels in the new residential buildings. In case of the traditional bourgeoisie houses in Beirut, there are no discussions about the use of HVAC systems to achieve the required thermal comfort level. Thus, to reach an acceptable thermal comfort level, these houses which already contain natural ventilation system shall adapt the modern thermal comfort requirements and thermal comfort strategies and technologies where their architectural features and existing materials condition the available solutions. In order to identify the best options within the possible intervention lines (envelopes, passive strategies, equipment, renewable energy systems), it is necessary to perceive the real performance of this type of houses. In this context, the article presents the results of the study of thermal performance and comfort in a three case studies located in Beirut. Detailed field data records collected are analyzed, with a view to identify the indoor thermal environment with respect to outdoor thermal environment in different seasons. Monitoring also included measurement of hygrothermal parameters and surveys of occupant thermal sensation.

scholarly journals LOW-COST AND NON-INVASIVE ENERGY RECOVERY TECHNIQUES FOR PUBLIC RESIDENTIAL BUILDINGS MADE WITH GREAT PANEL STRUCTURES IN ITALY

2019 ◽  
Vol 14 (3) ◽  
pp. 23-46
Author(s):  
Frida Bazzocchi ◽  
Sara Ticci ◽  
Vincenzo Di Naso ◽  
Andrea Rocchetti
Keyword(s):  
Energy Recovery ◽  
Energy Savings ◽  
Residential Buildings ◽  
Low Cost ◽  
Ventilation System ◽  
Energy Performance ◽  
Residential Units ◽  
Technical Solutions ◽  
Tunnel System ◽  
Indoor Comfort

In Italy, a large stock of public housing was built during the 1970s and 1980s with industrialized/prefabricated techniques. These buildings have envelopes characterized by the presence of many thermal bridges and low transmittance values. In addition, they feature inefficient single heating systems in residential units and no cooling/ventilation systems. As a result, these buildings require urgent energy retrofitting actions, and it is therefore necessary to define procedures that will guarantee effective results. The possible interventions must be compatible with building construction techniques as well as be minimally invasive and inexpensive. There are only a limited number of technical solutions, considering that residents should not have to move out during the renovations. In most Italian climatic zones, current interventions are usually linked to external insulation and window replacement, leading to an improvement in energy performance and comfort only during winter. Internal comfort conditions tend to worsen in summer months because seasonal temperatures tend to increase by a few degrees. Therefore, solutions should be proposed that will improve both summer and winter conditions. This work proposes an energy recovery procedure applied to a representative building from the abovementioned period located in the Florence area and constructed with an industrialized system named the “tunnel system” (great panels structure). The procedure used in this study provides for the redevelopment of the envelope and the application of a simple mechanical ventilation system to achieve substantial energy savings and improved indoor comfort conditions.

scholarly journals Effects of Cross Level Air Interaction within Multilevel Underground Carparks on Indoor Air Quality

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 177
Author(s):  
Rafat Al-Waked ◽  
Abdalrahman Yassin ◽  
Abdallah Adwan ◽  
Diala Bani Mostafa
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Flow Distribution ◽  
Sensitivity Study ◽  
Shopping Mall ◽  
Cfd Model ◽  
Ansys Fluent ◽  
Co Concentration

Ventilation for underground carparks is critical to indoor air quality (IAQ) due to carbon monoxide (CO) emissions from cars. The IAQ within a multi-level underground carpark of a shopping mall has been investigated using computational fluid dynamics (CFD) model based on ANSYS-FLUENT (18.1) software. The effects of car engines types, porosity of supply and exhaust air louvers and ventilation flow rates on IAQ were examined. A mesh sensitivity study was conducted and the CFD model was validated against the fully mixed mathematical formulations of IAQ with a maximum difference in values of 1.5 ppm and an error of 3.4%. The results showed that the ventilation system must be operated at ACH value of more than 2.7 in order to meet the required CO concentration of 50 ppm within the carpark and should be based on running cars within each level rather than the parking capacity of each level. Porosity of louvers affected air flow distribution between parking levels and led to higher dilution of CO. Therefore, modelling a multilevel underground carpark requires closer attention to cross level interaction across Ramps which could affect the CO concentration within a given level.

scholarly journals Design of a Passive Downdraught Evaporative Cooling Windcatcher (PDEC-WC) System for Greenhouses in Hot Climates

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2934 ◽  
Author(s):  
Marouen Ghoulem ◽  
Khaled El Moueddeb ◽  
Ezzedine Nehdi ◽  
Fangliang Zhong ◽  
John Calautit
Keyword(s):  
Relative Humidity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Evaporative Cooling ◽  
Cross Flow ◽  
Flow Distribution ◽  
Average Error ◽  
Ambient Conditions ◽  
Mass Flow Rates ◽  
Computational Fluid Dynamics Cfd

A windcatcher is a wind-driven natural ventilation system that catches the prevailing wind to bring fresh airflow into the building and remove existing stale air. This technology recently regained attention and is increasingly being employed in buildings for passive ventilation and cooling. The combination of windcatchers and evaporative cooling has the potential to reduce the amount of energy required to ventilate and cool a greenhouse in warm and hot climates. This study examined a greenhouse incorporated with a passive downdraught evaporative cooling windcatcher (PDEC-WC) system using Computational Fluid Dynamics (CFD), validated with experimental data. Different hot ambient conditions of temperature (30–45 °C) and relative humidity (15–45%) were considered. The study explored the influence of different spray heights, layouts, cone angles and mass flow rates on indoor temperature and humidity. The average error between measurements and simulated results was 5.4% for the greenhouse model and 4.6% for the evaporative spray model. Based on the results and set conditions, the system was able to reduce the air temperature by up to 13.3 °C and to increase relative humidity by 54%. The study also assessed the influence of neighbouring structures or other greenhouses that influence the flow distribution at the ventilation openings. The study showed that the windcatcher ventilation system provided higher airflow rates as compared to cross-flow ventilation when other structures surrounded the greenhouse.

scholarly journals Combination of Diagnostic Tools for the Proper Identification of Moisture Pathologies in Modern Residential Buildings

2018 ◽  
Vol 3 (3) ◽  
pp. 37
Author(s):  
Juan Hidalgo-Betanzos ◽  
César Escudero-Revilla ◽  
Eider Iribar-Solaberrieta ◽  
Iván Flores-Abascal ◽  
José Sala-Lizarraga
Keyword(s):  
Thermal Insulation ◽  
Natural Ventilation ◽  
Residential Buildings ◽  
Thermal Capacity ◽  
Accurate Diagnosis ◽  
Diagnostic Tools ◽  
Northern Spain ◽  
Thermal Bridge ◽  
Technical Solutions ◽  
Indoor Conditions

A study of moisture pathologies in a modern residential multifamily building is presented. The housing block was designed under the regulation NBE-CT of 1979 in northern Spain. After the appearance of some moisture problems in the façades, three complementary studies were conducted to analyze the situation of the envelope and diagnose the best improvement possibilities. First, indoor conditions of temperature and humidity of the apartments with moisture pathologies were monitored. During 40 winter days, the occupancy, heating operation, and natural ventilation were analyzed. Second, the inner and outer surface temperatures of the studied façades were measured. Thermal insulation degree, thermal capacity, and thermal bridge effects were measured to assess the risk of interstitial condensation under the real conditions of use. Third, an infrared thermographic survey was carried out, which allowed the detection of irregularities and the assessment of moisture problems. The wrong interpretations, which would have been made if the complementary studies had not been done, are exposed. The key towards the accurate diagnosis was the combination of tools. Finally, some technical solutions based on ventilation or thermal insulation enhancement are proposed as different ways to reduce the high levels of relative humidity indoors and minimize the risk of condensation in the future.

scholarly journals Simulation of Naturally Ventilated Underground Car Park with CFD

2020 ◽  
Vol 3 (SI3) ◽  
pp. SI22-SI28
Author(s):  
Huong Mai Thi Nguyen ◽  
Trương Tích Thiện
Keyword(s):  
Fire Safety ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Urban Land ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Car Park ◽  
Effective Ventilation ◽  
Fire And Explosion ◽  
Cfd Method

Nowadays, the speed of urbanization is increasing rapidly, so the urban land area is fully utilized to build high-rise buildings, apartments, and commercial centers, and thus, the car tunnel parking and basement parking basements also become more popular. However, apartment fire and explosion, especially car fire and explosion is an extremely important issue that must be concerned in construction design. Therefore, it is essential to design an effective ventilation system in the parking basement when a fire occurs an effective ventilation system for the tunnel is really necessary for basement firefighting. When building up the car park, the importance is not only a reasonable architecture but also the ventilation and air quality of the tunnel because it directly affects human health. Decades ago, scientists had studied the solution to ventilate the car park. The computational fluid dynamics (CFD) method is also applied to determine the pressure and velocity intensity for buildings that detect residuals in architecture, thereby improving and providing a superior solution. More for this problem. Many studies related to this issue have been published internationally. Jiang (Jiang, Allocca, & Chen, 2004) also investigated natural ventilation by using Reynolds Averaged Navier - Stokes turbulence model (RANS). Khalil (Khalil, Shoukry, H.A, & Harridy, 2015) also examined the distribution of CO emissions from buses in a basement in Cairo using ANSYS FLUENT software.The basement car park is a popular solution to effectively use urban land, especially in commercial centers and apartments. However, the situation of apartment fire and explosion is a hot problem, partly due to the tunnel ventilation has not met the requirements of fire safety. Therefore, the design of the car park basement ensures fire safety as well as bring comfort to people. In this study, the problem of basement temperature and wind velocity by natural ventilation method will be analyzed and evaluated in accordance with ADPI standard and Carbon monoxide concentration with WHO standard to identify areas of unsatisfactory temperature and velocity to reasonably adjust and propose other suitable ventilation options.

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