scholarly journals STATISTICAL METHODS TO ESTIMATE NATURAL FREQUENCY OF AIR CONDITIONER PIPING

2013 ◽  
pp. 30-34
Author(s):  
SWAPNIL A. PATIL ◽  
A. S. RAO ◽  
LALIT BAVISKAR
Keyword(s):  
Regression Analysis ◽  
Design Of Experiments ◽  
Regression Model ◽  
Natural Frequency ◽  
Statistical Methods ◽  
Air Conditioning ◽  
Geometrical Parameters ◽  
Air Conditioner ◽  
Refrigeration System ◽  
Hand Tool

Resonance is a critical phenomena in the designing of any structure. Piping structure, which is one of the several elements of air conditioning and refrigeration system, undergo severe vibration. In practice different approaches such as experimental, analytical, numerical and statistical methods are used to study vibration characteristics of a structure. Statistical method acts as a first hand tool to judge the behaviour of a system. Statistical methods minimise redesign process and expensive methods of controlling vibrations, saving significant amount of effort, cost and time. In the present study, statistical methods are used to estimate fundamental natural frequency of a pipe by selecting different geometrical parameters. The natural frequency obtained can be used to check resonance. Geometrical parameters, which significantly affect the natural frequency, are estimated by using Design of Experiments (DOE) and Analysis of Variance (ANOVA) techniques. A linear equation that predicts fundamental frequency is formulated using regression analysis. Frequencies predicted by regression model are compared to frequencies obtained from ANSYS Mechanical©. A good correlation is found with error less than 5%.

Analysis of Ejector in Central Air Conditioner Combined with Solar Ejector Refrigeration System

2013 ◽  
Vol 860-863 ◽  
pp. 733-736
Author(s):  
Hui Lan Huang ◽  
Gang Li ◽  
Xiang Chen ◽  
Zhong Yi Su
Keyword(s):  
Air Conditioning ◽  
Function Method ◽  
Air Conditioner ◽  
System Efficiency ◽  
Refrigeration System ◽  
System A ◽  
Central Air Conditioning ◽  
The Common ◽  
Main Component ◽  
Solar Refrigeration

Comparing with the common jet refrigeration system, a central air conditioner combined with solar ejector refrigeration system was proposed. The system characteristic was presented. It can improve the coefficient of the single solar system and solve operation problem for day-and-night, and can reduce the energy consumption of central air conditioner. A reasonable ejector to match with the central air conditioning is a main component in the system. The ejector in the solar refrigeration system is preliminary analyzed by the pneumatic function method. It will provide the important reference to improving the conditioner performance and system efficiency on air conditioning energy saving.

Analysis of Energy Factor Effectiveness in Air-Conditioning Refrigeration System

2011 ◽  
Vol 201-203 ◽  
pp. 1443-1446
Author(s):  
Yan Wang ◽  
Guang Fu Liu ◽  
Shou Xu Song ◽  
Ping He
Keyword(s):  
Design Process ◽  
Design Parameter ◽  
Air Conditioning ◽  
Air Conditioner ◽  
Refrigeration System ◽  
Coupling Energy ◽  
Energy Factor ◽  
Energy Effectiveness ◽  
Effectiveness Model ◽  
Energy Factors

This paper deals with the energy-saving product design involving the product energy property into design process. On the basis of the energy factors concepts, the paper analyzes the extraction process and energy effectiveness model of energy factors. To study the air-conditioning refrigeration system, the paper establishes the energy information model, recognizes the crucial and controllable energy element and extracts the energy factor set C = {compressor volumetric efficiency λ, motor efficiency ηd, power frequency fd, heat transfer performance coefficient φ, finned lateral general area Ao}. Then it makes a further decomposition of coupling energy factors λ, φ and finds out the corresponding design parameter. In the end, the paper maps the energy factors and design parameter into design process, establishes the energy effectiveness model and presents several measurers for decreasing the energy consumption during the actual use of air-conditioner.

Study on Water-Cooled Solar Semiconductor Air Conditioner

2015 ◽  
Vol 9 (1) ◽  
pp. 135-140
Author(s):  
Dong Zhi-Ming ◽  
Guo Li-Xia ◽  
Chang Ji-Bin ◽  
Zhou Xue-Bin
Keyword(s):  
Air Conditioning ◽  
Working Condition ◽  
Test System ◽  
Air Conditioner ◽  
Solar Panels ◽  
Experimental Room ◽  
Maximum Value ◽  
Cooling Unit ◽  
Battery Capacity ◽  
Solar Powered

Aiming to compare the cooling effect, two types of solar-powered semiconductor air-conditioning devices were designed in different structures. According to the cooling load in an experimental room, the solar panels and battery capacity were determined for the development of a test system. In the same working condition, a comparison test was carried out to examine the cooling performance. Experimental results showed that the design of dual water-cooled cooling unit presented a higher ratio of energy efficiency, with its maximum value of 1.08. By observing the experimental data of the prototype, its comparative economic evaluation results indicated that the annualized cost of solar semiconductor airconditioning was app. 2.7 times that of air-conditioning made from an ordinary compressor.

Investigation into steering wheel nibble

2002 ◽  
Vol 216 (4) ◽  
pp. 267-277 ◽  
Author(s):  
U Neureder
Keyword(s):  
Design Of Experiments ◽  
Natural Frequency ◽  
Dry Friction ◽  
Parameter Sensitivity ◽  
Steering Wheel ◽  
New Model ◽  
The Past ◽  
Force Variation

Many studies of mechanisms contributing to steering wheel nibble have been carried out in the past. This paper deals with some aspects that have not yet been studied, or those that have been presented by several authors but are deemed to be controversial. Firstly, an overview of stimulation sources (disturbance factors), and the significance these have with respect to steering nibble, is given. As an example of the controversial aspects of the problem, this paper deals with the assumption of dry friction in steering gear models and its conflict with the observed transfer of vibration caused by small (realistic) amounts of imbalance or tyre force variation. After modelling the steering gear resistance correctly, it is possible to identify, in the steering gear, a natural frequency that contributes reasonably to the nibble phenomenon. Based on this new model, a CAE study on parameter sensitivity, using the ‘design of experiments’ approach, is presented.

Experimental evaluation on a centralized air conditioning system embedded with a split-type air conditioner as a dedicated subcooler

2021 ◽  
pp. 102585
Author(s):  
Kasni Sumeru ◽  
Mohamad Firdaus Sukri ◽  
Triaji Pangripto Pramudantoro ◽  
Eddy Erham ◽  
Rizki Muliawan
Keyword(s):  
Experimental Evaluation ◽  
Air Conditioning ◽  
Air Conditioner ◽  
Air Conditioning System

scholarly journals Optimal Air Conditioner Placement Using a Simple Thermal Environment Analysis Method for Continuous Large Spaces with Predominant Advection

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4663
Author(s):  
Tatsuhiro Yamamoto ◽  
Akihito Ozaki ◽  
Myonghyang Lee
Keyword(s):  
Air Conditioning ◽  
Thermal Environment ◽  
Fluid Dynamic ◽  
Optimal Placement ◽  
Air Conditioner ◽  
Analysis Method ◽  
Computational Fluid Dynamic Analysis ◽  
Environment Analysis ◽  
Air Conditioners ◽  
Energy Simulations

The number of houses with large, continuous spaces has increased recently. With improvements in insulation performance, it has become possible to efficiently air condition such spaces using a single air conditioner. However, the air conditioning efficiency depends on the placement of the air conditioner. The only way to determine the optimal placement of such air conditioners is to conduct an experiment or use computational fluid dynamic analysis. However, because the analysis is performed over a limited period, it is difficult to consider non-stationarity effects without using an energy simulation. Therefore, in this study, energy simulations and computational fluid dynamics analyses were coupled to develop a thermal environment analysis method that considers non-stationarity effects, and various air conditioner arrangements were investigated to demonstrate the applicability of the proposed method. The accuracy verification results generally followed the experimental results. A case study was conducted using the calculated boundary conditions, and the results showed that the placement of two air conditioners in the target experimental house could provide sufficient air conditioning during both winter and summer. Our results suggest that this method can be used to conduct preliminary studies if the necessary data are available during design or if an experimental house is used.

scholarly journals Energy-saving diagnosis model of central air-conditioning refrigeration system in large shopping mall

2021 ◽  
Vol 7 ◽  
pp. 4035-4046
Author(s):  
Wenqiang Jing ◽  
Junqi Yu ◽  
Wei Luo ◽  
Chujun Li ◽  
XinYi Liu
Keyword(s):  
Energy Saving ◽  
Air Conditioning ◽  
Shopping Mall ◽  
Refrigeration System ◽  
Central Air Conditioning ◽  
Diagnosis Model

Solar Heat Underground Storage Based Air Conditioning Vis-à-Vis Conventional HVAC Experimental Validation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Carlos R. de Nardin ◽  
Felipe T. Fernandes ◽  
Adriano J. Longo ◽  
Luciano P. Lima ◽  
Felix A. Farret ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Heat Pumps ◽  
Conventional Heating ◽  
Management Technique ◽  
Air Conditioner ◽  
Heat Management ◽  
Air Conditioners ◽  
Solar Heat ◽  
Reduction Of Energy Consumption ◽  
The One

This paper presents a comparison of air conditioners using the conventional heating, ventilation, and air conditioning heat pumps and the one using solar heat stored underground, also known as shallow geothermal air conditioning. The proposed air conditioner with solar heat stored underground reunites practical data from an implementation of the heuristic perturb-and-observe (P&O) control and a heat management technique. The aim is to find out the best possible heat exchange between the room ambient and the underground soil heat to reduce its overall consumption without any heat pump. Comparative tests were conducted in two similar rooms, each one equipped with one of the two types of air conditioning. The room temperature with the conventional air conditioning was maintained as close as possible to the temperature of the test room with shallow geothermal conditioning to allow an acceptable data validation. The experiments made both in the winter of 2014 and in the summer of 2015 in Santa Maria, South Brazil, demonstrated that the conventional air conditioner consumed 19.08 kWh and the shallow geothermal conditioner (SGC) consumed only 4.65 kWh, therefore, representing a reduction of energy consumption of approximately 75%.

Thermal Energy Requirements of Air-Conditioning Systems

1971 ◽  
Vol 93 (2) ◽  
pp. 172-176
Author(s):  
M. E. Lackey
Keyword(s):  
Thermal Energy ◽  
Air Conditioning ◽  
Waste Heat ◽  
Energy Requirements ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Fast Breeder Reactors ◽  
Breeder Reactors ◽  
Absorption Refrigeration System ◽  
Air Conditioning Systems

The thermal energy requirements for air conditioning by compressive and absorption methods were determined for light-water, thermal-breeder, and fast-breeder reactors. The energy required to produce a ton-hour of refrigeration varied from 5100 Btu to 13,100 Btu by absorption and from 5600 to 8800 Btu by compression. The amount of waste heat dissipated to the environment at the reactor site as a consequence of producing a ton-hour of air conditioning ranged from an increase of 21,000 Btu for the electric-motor-driven refrigeration system to a decrease of 6000 Btu for the absorption refrigeration system.

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