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2021, Journal of emerging technologies and innovative research
Air conditioning systems are considered operating successfully based on the efficient supply of air in the air-conditioned space. Estimation of pressure losses in ducts is vital for the selection of duct size. The installation cost of duct in air conditioning system is about 20 to 30% of the total cost of equipment selection and power consumption of supply fans also adds to the running cost. Hence, it's important to minimize the capital and running cost of the duct system. Duct design is the design of enclosed passage for supplying conditioned air and then distributing the sir to specified areas according to the need. There are various advantages of efficiently designed and constructed interior ducts. One of the advantages is enhanced energy efficiency through the cancellation of duct leakage and reducing conductive heat gains/losses. This paper focuses on a study of design and improving air duct using computational fluid dynamics (CFD) analysis considering all the parameters related to air flow and its characteristics for enhancing duct system efficiency. The necessity of optimization of duct system is to improve supply air flow. It integrates theoretical and software tools to provide detailed comparative analysis of the advantages involved in selecting a particular shape (rectangular duct with Y-shaped bend and with 90-degree corner with sharp bend) of duct for a specified conditions. The focus of this paper will be on using CFD simulation tools to study velocity distribution of air in the duct at various sections, pressure difference at various outlets and distributions of air flow.
The optimal layout and sizing of duct systems has become more and more a concern for HVAC system designers. Although most duct systems are designed either by an HVAC contractor or a consulting engineer, many plant designers often find it necessary to alter a duct system design to correct obvious flaws. Not only duct system modifications are made to clear obstructions, but also they are sometimes made for obvious economic reasons. The original design may include high cost, unnecessary transitions and special fittings. An experienced sheet metal person can quickly spot these anomalies in a duct design. However, modifications to a duct design must be made carefully to ensure that the system will work as intended. Rather than performing initial design or modifying someone else's design, it is a good idea to analyze proposed duct systems with simulation software to ensure that they will work properly. So in this project simulation software is developed to design an economic air conditioning duct system. This software is helpful to determine the duct sizes and pressure losses in each duct section both in main duct sections as well as branch duct sections by following equal friction method and static regain method. It is also used to determine pressure required at blower/fan exit and the capacity required for the blower. When duct-sizing calculations are done manually, it needs a big amount of money and time but by using this software a designer can design a duct system in a fraction of the time required by analytical method.
Journal of emerging technologies and innovative research, 2018
The successful operation of any air-conditioning system is dependent upon the sufficient circulation of air in the airconditioned space. The careful estimation of the pressure losses is necessary for the selection of proper duct size. The duct cost in air conditioning system is 20 to 30 % of the total cost of the equipment's requirement and power required by the fan contributes the substantial part of the running cost. It is, therefore, necessary to design an air duct system for least capital cost & lowest running cost of the fan. Duct design is the design of pipes which convey conditioned air and then distribute it to different spaces according to the requirement. The advantages of well designed and constructed interior duct systems are numerous. Among these advantages are improved energy efficiency through the elimination of duct leakage to outside and the elimination of conductive heat gains/losses. This paper focuses on a study of design and modifications air cooling duct us...
It is very important to study and analyze the air distribution and thermal effects of the conditioned air that is supplied to the cabin. This is because all the passengers should be comforted with the ac system. The ac system is one of the most popular features of the automobile industry. In this work, a numerical investigation is carried out using the commercial software ANSYS about the flow and thermal analysis of the cabin air circulation. We had created a 3d model of the maruti 800 car using design modeler and it is analyzed using the FLUENT software. Contours of velocity and temperature distribution are studied in detail. Four different combinations like front vent, front and rear vent, front and rear side vent, front and rear top vent are created and analyzed. The best configuration is find out from the temperature and velocity analysis.
The present investigation concentrates in characterizing the air flow pattern inside a HVAC Duct used in a local supermarket. The duct chosen for this investigation are rectangular in shape with varying hydraulic diameter. The total length of the duct in the present investigation is 21.8 m. There are 7 diffusers with an air flow rate of 140 L/s each in the duct system. The designed room temperature is 23°C and outside temperature is 35°C. There are 7 SD5-10 type and a single elbow type fittings in the duct system. The numerical model is based on the actual dimension of the duct to visualize the effect of flow friction and other characteristics in the duct system. The results obtained in the numerical analysis are then validated using the actual pressure drop in each inlet diffuser of the each room.
International Journal of Scientific Research, 2015
With the improvement of standard of living, airconditioning has widely been applied. However, health problems associated with airconditioning systems and indoor air quality appear more frequently. The present paper deals with CFD study of flow and thermal characteristics in air-conditioned rooms under turbulent mixed convection conditions. Air enters room from a sidewall slot flush with isothermal ceiling and leaves through a slot in opposite wall flush with floor. The numerical simulation of air distribution in indoor space with displacement ventilation using CFD is challenging due to complexity of air diffuser geometry and the complicated air flow pattern. This paper investigates experimental and numerical study of the airflow characteristics for vortex, round and square ceiling diffusers and its effect on the thermal comfort in a ventilated room. The performance of indoor airflow for the office room with the hybrid airconditioning system has been investigated by means of CFD analysis. The performance of indoor airflow for the office room with the hybrid airconditioning system has been investigated by means of CFD analysis.
Appropriate air distribution in a room is necessary for thermal comfort. By using Computational Fluid Dynamics (CFD) it is possible to compare optional ways of air supply and distribution at the stage of the ventilation design concept. Using these simulations the ventilation system designer can choose the best method of air supply in the room diminishing the risk of an incorrect solution.
journal of Aerospace Science and Technology, 2021
In the present study, the aerodynamic performance of the ducted fan is investigated using the surface vorticity method and the lifting line theory. In previous research, to consider the effects of the duct, most of the parameters derived from empirical tests or computational fluid dynamics. Our goal is to present a new method for considering the effects of the duct on the fan enclosed in a duct. In this method, the lift and drag coefficients are only input parameters. The present method requires considerably less computational time than CFD methods. Also, the aerodynamic optimization of fan blades geometry has been carried out using particle swarm optimization method (PSO) to achieve the optimum blade geometry and the maximum output power. The results of this method are in excellent agreement with experimental data in references. By optimizing the geometry of the blade, the output power of ducted fan increased 10 percentage in comparison to ducted fan with old blade geometry
For sustainable design of proper location of inlet and outlet windows, uniform flow is possible at working area. Tunnel study was performed by researchers to understand the flow patterns. Since civil engineering structures are of civil engineering structures. With availability of advance computing hardware and software, it is possible to model the air flow on desktop computer. Computational Fluid Dynamics (CFD)has open new doo problems on computers. Researchers and software developing company has validated the software with experimental results. Paper present the air flow pattern inside the room. Autodesk CFD2016 Simulation tool was used for simulation. Twelve Simulation cases with different inlet and outlet window location were defined. For every case, air velocity was measured inside room at working plane. Cumulative air velocity at observation points are compared between different cases. Simulation case which give maximum circulation of air on working plane was selected as best alternative. As per simulation result it is found that, if windows are placed at crossing, then maximum air circulation can be achieved. Air flow found to be maximum when inlet and outlet windows are placed on opposite walls. Vector diagrams of air circulation for different cases are helpful to understand the air flow inside the room. For sustainable design of building ventilation plays very important role. With proper location of inlet and outlet windows, uniform flow is possible at working area. Tunnel study was performed by researchers to understand the flow patterns. Since civil engineering structures are of very big scale, there is limitation on tunnel study of civil engineering structures. With availability of advance computing hardware and software, it is possible to model the air flow on desktop computer. Computational has open new doors for researchers to simulate practical problems on computers. Researchers and software developing company has validated the software with experimental results. Paper present the air flow pattern inside the room. Autodesk CFD2016 Simulation for simulation. Twelve Simulation cases with different inlet and outlet window location were defined. For every case, air velocity was measured inside room at working plane. Cumulative air velocity at observation points are compared between es. Simulation case which give maximum circulation of air on working plane was selected as best alternative. As per simulation result it is found that, if windows are placed at crossing, then maximum air circulation can be achieved. Air ximum when inlet and outlet windows are placed on opposite walls. Vector diagrams of air circulation for different cases are helpful to understand the air flow inside the room. building ventilation plays very important role. With proper location of inlet and outlet windows, uniform flow is possible at working area. Tunnel study was performed by researchers to understand the flow patterns. Since very big scale, there is limitation on tunnel study of civil engineering structures. With availability of advance computing hardware and software, it is possible to model the air flow on desktop computer. Computational rs for researchers to simulate practical problems on computers. Researchers and software developing company has validated Paper present the air flow pattern inside the room. Autodesk CFD2016 Simulation for simulation. Twelve Simulation cases with different inlet and outlet window location were defined. For every case, air velocity was measured inside room at working plane. Cumulative air velocity at observation points are compared between es. Simulation case which give maximum circulation of air on working plane was selected as best alternative. As per simulation result it is found that, if windows are placed at crossing, then maximum air circulation can be achieved. Air ximum when inlet and outlet windows are placed on opposite walls. Vector diagrams of air circulation for different cases are helpful to understand
Journal of Marine Science and Engineering
Ventilation ducts with a high cross-sectional area are frequently built as structural ducts that include inside transversal structural beams. In this way, the cross-sectional area requested is respected, but the transverse structural elements will have a big impact on the airflow, with eventually additional noise and vibration and a high amount of energy wasted across the beams. From this perspective, the aim of this study is to evaluate the impact of the transversal beams inside the ventilation ducts, to analyze different alternatives for airflow improvement using computational fluid dynamics (CFD) simulation, and to check the simulation results in the wind tunnel with an experimental model. The results of the experimental measurements have highlighted the high-pressure drop and, consequently, the high energy wasted across the transversal structural beams. It was found that the airflow downstream of the beam is changing the flow direction, and high turbulences and vortices are init...
International Journal of Innovation in Mechanical Engineering and Advanced Materials
This paper focuses on the calculation of sizing ducting based on cooling load requirements the main ducting of office building following regulation airspeed requirements using American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) and Computational Fluid Dynamics (CFD) simulations. The purpose of this research is to validate the airspeed and turbulence that occurs in the main ducting between manual calculations and CFD simulations. From the calculation, the cooling load requirement is 58.22 kW, for the cooling process an air flowrate of 7117 L/s is needed which is designed to pass through the main ducting in rectangular shape. The main ducting size uses 1200 mm x 500 mm at a speed of 12.7 m/s according to ASHRAE. Autodesk Inventor software is used for ducting modeling and Autodesk CFD is used for airflow simulation. CFD simulations are performed by applying boundary conditions and input parameters. The results showed that the velocity of the ducting desig...
International Journal of Energy Resources Applications
Solar air heater (SAH) has vast applications in agriculture, crop drying and other field. In solar air heater, air temperature increases at the exit section. Research has worked extensively in SAH field, experimentally and numerically to observe the performance of SAH. In the present work, a 3D model of SAH is created in Design Modeler of ANSYS and simulation is run in ANSYS Fluent for the Reynolds number range between 2000-18000. Main objective of the study is to calculate the Nusselt number (dimensionless number) and friction factor influenced by pressure drop inside the duct. Numerical results are validated with the experimental results and compared with the Modified Dittus-Boelter equation and Modified Blasius equation. Mean percentage absolute error in simulation results are within range of 10%.
2020
Computational simulation is known to be used for decades. One such platform known to be available for simulating the fluid dynamics (CFD) was used mostly in the field of Aeronautic, Space, Automotive or Electronics industries owing to its high cost, complexity and the low performance of computers. With the significant increase in computing power and reduction of equipment cost, the use of CFD is easily accessible and is gaining momentum significantly in the cement industry. This paper highlights the recent study done for a cement plant in western India. The plant is suffering severely with the pressurisation in complex ducting arrangement handling the flue gases. The cement plant is designed to produce 9000 tpd clinker from a single kiln with 3 string preheaters. The fan outlets of each string preheater is connected to a common junction duct (PH-junction duct) from which the gases are bifurcated to coal mill, raw mill and directly to the dust collector. The plant is also having anot...
International Journal of Innovative Science and Research Technology, 2020
This paper presents numerical predictions and results of air flow and pressure distribution in common possible iterations of duct and diffuser having: 1. square, rectangle and circular duct shape, 2. square duct with side 12in, 15in and 18in and 3. bend radius to width ratio of 0, 0.5, 1 and 2. The system is designed to develop an optimal system to reduce the noise levels in a classroom which are far above the recommended value of 35dB by WHO in an engineering institution designed according to the Common Public Works Department(CPWD) norms while also bridging the gap between the industry and the consumer. The iterations were designed on fusion 360 and tetrahedron meshing was done in ANSYS after defining the boundaries of geometry of CAD design. The inlet velocities varied as per the different diffuser size, shape and angles. The inlet velocity lies in the range of 1.5m/s to 3m/s. After setting up the solver and choosing k-omega SST model for solving, calculation was performed for 30...
This test case was calculated using a commercial finite volume CFD computer code ANSYS 12.0 Fluent. The geometry of Model is a three-dimensional turbulent flow over a 90° bend. Experimental setup comprising an open-circuit suction wind tunnel system for the 90° bend which is used in ducting of centralized A. C. plant in various buildings or Malls. This test case focuses on the use of approximate models such as the turbulence models to predict the physical characteristics of the turbulent flow around a 90° bend. The results from the more sophisticated Reynolds stress model are shown to better capture the anisotropy behavior of the flow in contrast to the standard k-ε model that assumes isotropy in its original model formulation and also k-w SST model use to comparison. Finite Volume Discretization (FVM) is employed to approximate the governing equation. Velocity and pressure distribution at bend show by simulation of fluent CFD Code. By increasing the bend length in duct, losses can be reduce.
Research, Society and Development
The main purpose of this work is to perform a thermal analysis in an air conditioning duct to verify the influence of the thermal properties of the insulating material on the minimum thermal insulation thickness necessary to avoid the condensation of water vapor present in the air. The mathematical formulation is based on Fourier’s law and the first law of thermodynamics. A response surface, a contour plot and a mathematical model for the analyzed response variable, were obtained from an experimental design. Results indicate that the reduction of thermal conductivity and increase of emissivity of the insulating material contribute to the reduction of the minimum thermal insulation thickness.
Human comfortness is essential now a day because of the improvement in life style and increasing central air conditioning is more reliable for easy operation with a lower maintenance cost. With large buildings such as commercial complex, auditorium, office buildings are provided with central air conditioning system. Educational and research institutions also need human comfortness, as the population of student community increase year by year. The effective designing of ducting in central air conditioning can provide human comfort, low power consumption, capital cost and improve asthetic of building. This project establishes the results of duct designing for air conditioning using ASHRAE for a commercial building. Duct design items such as duct size, CFM each space pressure drop at each diffuser, elbow, T, taper reducer and duct class, duct material. Using ASHRAE and SMACNA fundamental hand book, maintaining ASHRAE and SMACNA standard.
Current World Environment/Current world environment, 2024
The Air distribution phenomenon is most useful in thermal environment study and its effectiveness. The main aim of this investigation is to examine and discover the thermal properties of the inside area and its thermal environment. The experimental work for research was studied at the firstfloor lab of the government women's polytechnic, Bhopal. The experiment was conducted in the summer and winter seasons in a closed-conditioned room with the arrangement of a conditioned air discharge duct. The conditioned air was discharged through the circular pipe duct which was set vertically. The duct has arrangements to discharge the air through various vertical positions as the lower duct (L), middle duct (M), and upper duct (U). This experimental work investigates supply air velocity and vertical temperature variation effectiveness inside said test room. The experiment results were collected with lower, middle, and vertical duct opening conditions respectively. The vertical temperature variation and air velocity at the outlet of the duct were noted with considerable points at 1 m from each inside the test room space. The outcome of the results shows the indoor thermal environment and vertical temperature distribution were affected by the discharge air duct position and supply air velocity. The temperature profile vertically impacted when the measuring test point position was near the discharge air duct and it became quite consistent in respective measurements from a large distance.
2015
Mechanical Heating Ventilation and Air-Conditioning (HVAC) systems account for 60% of the total energy consumption of buildings. As a sector, buildings contributes about 40% of the total global energy demand. By using passive technology coupled with natural ventilation from wind towers, significant amounts of energy can be saved, reducing the emissions of greenhouse gases. In this study, the development of Computational Fluid Dynamics (CFD) analysis in aiding the development of wind towers was explored. Initial concepts of simple wind tower mechanics to detailed design of wind towers which integrate modifications specifically to improve the efficiency of wind towers were detailed. From this, using CFD analysis, heat transfer devices were integrated into a wind tower to provide cooling for incoming air, thus negating the reliance on mechanical HVAC systems. A commercial CFD code Fluent was used in this study to simulate the airflow inside the wind tower model with the heat transfer devices. Scaled wind tunnel testing was used to validate the computational model. The airflow supply velocity was measured and compared with the numerical results and good correlation was observed. Additionally, the spacing between the heat transfer devices was varied to optimise the performance. The technology presented here is subject to a patent application (PCT/GB2014/052263).
In subtropical zone, cooling (A/C) is broadly used to give an appropriate warm indoor climate. During activity, numerous boundaries or arrangements may impact the exhibition of the A/C framework. Among them, the inventory vane point is a significant factor, which can impact the energy saving and warm solace level in the involved zone, as indicated by recently related investigations. Nonetheless, it was uncovered that it was hard to get a harmony between these two perspectives. Accordingly, in view of the past investigation, this further examination was directed planning to decide the reasonable point to accomplish the best exhibition. Consequently, the strategy for request inclinations by similitude to an ideal arrangement of air diffuser system Computational Fluid Dynamics approach (CFD) was utilized to compute the consolidated presentation considering energy saving and warm solace. Three angles were selected i.e. 7, 8 and 9 ° for diffusor location. Different parameters such as ambient temperature and diffusor angle were also selected for the study.
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