scholarly journals Computational fluid dynamics analysis in the ductless whole-house air conditioning system

2020 ◽  
Vol 172 ◽  
pp. 03008
Author(s):  
Rie Tasaka ◽  
Sayaka Kindaichi ◽  
Daisaku Nishina ◽  
Mitsuhiko Maeoki
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Load ◽  
Air Conditioning ◽  
High Energy ◽  
Space Heating ◽  
Cfd Analysis ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Computational Fluid Dynamics Analysis

Recently, the heat load for space heating in residential houses has been reduced as airtightness, and thermal insulation performance has been improving even in moderate climate regions of Japan. In such situations, the heat load can be handled by one room air-conditioner with high energy efficiency. We report the results of computational fluid dynamics (CFD) analysis of an indoor thermal environment and the airflow distribution during the space heating operation in a ductless house air conditioning system, in which heated air from a room air conditioner installed in a thermal-insulated basement space is distributed throughout the building using air inlets on the floor in each story and open-door rooms without ductworks. To determine the adequate size and position of the air inlets on the floor in this heating system, we evaluated the air circulation performance for changes in the conditions of the air inlets by CFD analysis for a standard two-storey house model in Japan. The results suggest that the air temperature distribution is markedly different in the size and position of the air inlets on the floor. Large volumes of airflow through the openings in the building resulted in maintaining the rooms at a temperature range of 17 to 24 degrees uniformly. These results also provide information for system and building designs for effective space heating and for proper usage when choosing to open or close air inlets in the operational phase.

Computational Fluid Dynamics Analysis on Underfloor Air Distribution (UFAD) System in BTLab

2007 ◽  
Author(s):  
Huajun Chen ◽  
Yitung Chen ◽  
Hsuan-Tsung Hsieh ◽  
Liangcai Tan ◽  
Davor Novosel
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Systems Design ◽  
High Energy ◽  
Design Guidelines ◽  
Air Distribution ◽  
Cfd Analysis ◽  
Computational Fluid Dynamics Analysis ◽  
Underfloor Air Distribution ◽  
The Impact

As an alternative to Conventional Air Distribution (CAD) systems, underfloor air distribution (UFAD) systems have been widely used in different country. Although many advantages of a well-designed UFAD system can be found, there is still a higher risk to designers and building owners due to a lack of objective information and standardized design guidelines. UFAD systems design have been influenced by increasing emphasis on indoor air quality (IAQ), energy conservation, environmental effects, safety, and economics. To investigate the performance of the UFAD system, a detailed 3-D computational fluid dynamics (CFD) analysis on the turbulent buoyancy flow and heat transfer inside the BTLab, which locates at University of Nevada, Las Vegas, has been made in this paper. The particular interest has been concentrated on the flow distribution through underfloor swirl diffuser. By CFD analysis with unstructured meshes associated with using parallel processing, the impact of different operating parameters on the air flow and temperature distribution has been studied in detail. Usefully information has been provided on the development of high energy efficiency with human comfort of UFAD systems.

Humidity Distribution Simulation of Passenger Vehicle Cabin

2013 ◽  
Vol 291-294 ◽  
pp. 1880-1883
Author(s):  
Li Ping Xiang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Air Conditioning ◽  
Passenger Vehicle ◽  
Air Conditioning System ◽  
Moisture Effect ◽  
Vehicle Cabin ◽  
Hygienic Standard ◽  
Computational Fluid Dynamics Cfd ◽  
Passenger Cabin

A numerical model to improve the air-conditioning system of vehicle cabin taking into the cabin air moisture and its transport by the airflow within the enclosure cabin is described. An efficient computational fluid dynamics(CFD) technique is using the “realisable” model. The temperature and humidity fields in the passenger cabin are investigated individually under having or no body moisture. The temperature in the vehicle cabin taking into account human moisture is lower than no taking into account moisture 0.5 °C. The human dispersing moisture effect significantly on the humidity, which lead to the humidity is elevating and the humidity in vehicle cabin is corresponded hygienic standard.

Effect of Air Conditioning Position on Thermal Comfort in the Floor Air Conditioning System

2014 ◽  
Vol 493 ◽  
pp. 74-79
Author(s):  
Y.A. Sabtalistia ◽  
S.N.N. Ekasiwi ◽  
B. Iskandriawan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Energy Consumption ◽  
Thermal Comfort ◽  
Energy Efficient ◽  
Air Conditioning ◽  
Air Conditioning System ◽  
Air Supply ◽  
Air Conditioning Systems ◽  
Air Diffusion

Energy consumption for air conditioning systems (air conditioning system) increased along with the increasing need for fresh air and comfortable in the room especially apartments. FAC system (Floor Air Conditioning) is growing because it is more energy efficient than CAC (Ceiling Air Conditioning) system. However, the position of the AC supply is on the lower level at the FAC system causes draft discomfort becomes greater as air supply closer to the occupants so that thermal comfort can be reduced. Heat mixture of windows, exterior walls, kitchen, and occupants in the studio apartment affect thermal comfort in the room too.This study aims to determine the position of the AC supply which has the best thermal comfort of FAC system in the studio apartment. It can be done by analyzing ADPI (Air Diffusion Performance Index), the distribution of air temperature, wind speed, RH (Relative Humidity), and DR (Draft Risk) to change the position of the AC supply supported by CFD (Computational Fluid Dynamics) simulation.This result prove that AC position 2 (on wall near the kitchen) is more comfortable than AC position 1 (on the bathroom wall) because AC position 2 away from occupied areas, thereby reducing the occurrence of draught discomfort.

scholarly journals ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ КОНДИЦІЮВАННЯ ЗОВНІШНЬОГО ПОВІТРЯ СИСТЕМИ КОМБІНОВАНОГО ТИПУ

2019 ◽  
pp. 9-14
Author(s):  
Євген Іванович Трушляков ◽  
Андрій Миколайович Радченко ◽  
Микола Іванович Радченко ◽  
Сергій Анатолійович Кантор ◽  
Веніамін Сергійович Ткаченко
Keyword(s):  
Heat Load ◽  
Air Conditioning ◽  
Rational Design ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Energetic Efficiency ◽  
Cooling Load ◽  
Air Conditioner ◽  
Outdoor Air ◽  
Air Conditioning System

One of the most attractive reserves of enhancing the energetic efficiency of air conditioning systems is to provide the operation of refrigeration compressors in nominal or close to nominal modes by choosing rational design cooling loads (cooling capacities) and their distribution according to a cooling load behaviour within the overall design (installed) cooling load band to match current changeable climatic conditions and provide close to maximum annual cooling capacity generation according to cooling duties. The direction of increasing the efficiency of outdoor air conditioning in combined central-local type systems by rationally distributing the heat load - cooling capacity of the central air conditioner into zones of variable heat load in accordance with current climatic conditions and its relatively stable value, i.e. cooling capacity required for further air cooling at the entrance to the indoor recirculation air conditioning system is justified. By comparing the values of the excessive production of cold and its deficit within every 3 days for a rational design heat load of the air conditioning system (cooling capacity of the installed refrigeration machine), which provides close to maximum annual production of cold, and the corresponding values of the excess and deficit of cooling capacity in accordance with current climatic conditions during July substantiated the feasibility of accumulating the excess of cooling capacity of a central air conditioner at low current loads and its use for covering cooling deficit at elevated heat loads through pre-cooling the outdoor air. It is developed a scheme of a combined central-local air conditioning system, which includes the subsystems for the outdoor air conditioning in a central air conditioner and the local indoor recirculated air conditioning.

scholarly journals Aerodynamic Analysis of Spoiler at Varying Speeds and Angles

2021 ◽  
Vol 9 (11) ◽  
pp. 526-535
Author(s):  
Manas Metar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Analysis ◽  
Wake Region ◽  
Aerodynamic Analysis ◽  
Pressure Drag ◽  
High Speeds ◽  
Computational Fluid Dynamics Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

Abstract: Spoilers have been there in practice since years for the purpose of improving aerodynamics of a car. The pressure drag created at the end of the vehicle, referred to as wake region affects handling of the vehicle. This could be hazardous for the cars at high speeds. By adding a spoiler to the rear of the car reduces that pressure drag and the enhanced downforce helps in better traction. The paper presents aerodynamic analysis of a spoiler through Computational Fluid Dynamics analysis. The spoiler is designed using Onshape software and analyzed through SIMSCALE software. The simulation is carried out by changing angles of attack and velocities. The simulation results of downforce and drag are compared on the basis of analytical method. Keywords: Designing a spoiler, Design and analysis of spoiler, Aerodynamics of spoiler, Aerodynamic analysis of spoiler, Computational fluid dynamics, CFD analysis, CFD analysis of spoiler, Spoiler at variable angles, Types of spoilers, Analytical aerodynamic analysis.

Evaluation of Jet Impact Region and Fluid Force Generated From Ruptured Pipes: 2 — Evaluation of Fluid Force Using Computational Fluid Dynamics Analysis

2016 ◽  
Author(s):  
Shiro Takahashi ◽  
Qiang Xu ◽  
Noriyuki Takamura ◽  
Ryo Morita ◽  
Yuta Uchiyama ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nuclear Power ◽  
Power Plants ◽  
Jet Impingement ◽  
Cfd Analysis ◽  
Fluid Force ◽  
Free Jet ◽  
Jet Impact ◽  
Computational Fluid Dynamics Analysis

Nuclear power plants are designed to avoid damage to their safety installations because of jet impingement when a pipe is ruptured. We have investigated evaluation methods for the design basis of protection of plants against effects of postulated pipe rupture using computational fluid dynamics (CFD) analysis. The steam jet tests obtained using particle image velocimetry (PIV) were conducted in order to verify the CFD analysis. Spread of steam jets could be visualized and the shapes of the steam jets obtained by analysis were almost the same as those by tests. The spread angle of free jet was investigated using CFD analysis. We also measured jet fluid force when a cylindrical structure was installed downstream from the jet nozzle. Steam jet fluid force obtained by analysis was almost the same as that by tests. We judged the CFD analysis to be applicable to evaluation of jet fluid force generated from ruptured pipes.

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