Experimental Investigation of the Parameters Influencing Refrigerant Migration in a Refrigeration System

2007 ◽  
Author(s):  
Serdar Kocaturk ◽  
Yalcin Guldali ◽  
A. Nilufer Egrican
Keyword(s):  
Experimental Parameter ◽  
Solenoid Valve ◽  
Experimental Facility ◽  
Refrigeration System ◽  
Pressure Equalization ◽  
Cycling Frequency ◽  
Temperature And Pressure ◽  
Set Up ◽  
Compressor Power ◽  
Condensing Pressure

Refrigerant migration, which is characterized by the pressure equalization between condenser and evaporator during compressor off period, is one of the most effective cycling losses phenomena with the cause of 5–15% increasing rates in the energy consumption of a refrigeration system. In this study, an experimental facility was set up to investigate the parameters influencing refrigerant migration. A freezer cabinet with wire&tube evaporator and R600a and R134a reciprocating compressors were used. For the detailed control of various condensing parameters (condensing temperature, pressure, condensing rate in the condenser) a double-tube water-cooled condenser was designed. The condenser was constructed to allow the application of various lengths. Temperature and pressure values on various points of the system, refrigerant mass-flow rate, compressor power and consumed energy values were measured simultaneously. Condensing pressure and condensing rate in the condenser, condenser length, cycling frequency, refrigerant type used in the system, and ambient temperature were investigated as parameters influencing refrigerant migration. Refrigerant migration during the off period was blocked with a solenoid valve that is located before the inlet of the expansion device, and energy consumptions and COP values were mainly compared for the opened-valve and closed-valve conditions for each controlled experimental parameter.

The Impact of Condensing Pressure on the Performance of Solar Solid Adsorption Refrigeration System

2015 ◽  
Vol 1092-1093 ◽  
pp. 109-112
Author(s):  
Xiang Bo Song ◽  
Xu Ji ◽  
Ming Li ◽  
Jia Xing Liu ◽  
Shao Lin Yin
Keyword(s):  
Working Conditions ◽  
System Performance ◽  
Refrigeration System ◽  
Adsorption Refrigeration ◽  
Bed Temperature ◽  
Temperature And Pressure ◽  
Condensing Pressure ◽  
The Impact

A new solar solid adsorption refrigeration system is established in this paper, and the variation relationship between the adsorbent bed temperature and pressure with time are analyzed, and the effects of adsorbent bed condensing pressure on the system performance is researched. Results show that, under the same working conditions, when the condensing pressure is 39 kPa, the daily ice-making capacity of system reach to 5.5 kg with the refrigerating capacity of 2.26 MJ; And when the condensing pressure is 63 kPa, the ice-making capacity of system is only for 3 kg with the refrigerating capacity of 1.48 MJ; The refrigerating capacity of the former is 1.5 times of the latter.

scholarly journals Numerical calculation and experimental study on response characteristics of pneumatic solenoid valves

2019 ◽  
Vol 52 (9-10) ◽  
pp. 1382-1393 ◽  
Author(s):  
Xiang Zhang ◽  
Yonghua Lu ◽  
Yang Li ◽  
Chi Zhang ◽  
Rui Wang
Keyword(s):  
Switching Time ◽  
Response Characteristic ◽  
Test System ◽  
Solenoid Valve ◽  
Circuit Model ◽  
Inlet Pressure ◽  
Driving Voltage ◽  
Response Characteristics ◽  
Aerodynamic Model ◽  
Set Up

In order to analyze the response characteristics of the solenoid valve in depth, the flow field of the solenoid valve is analyzed by means of the computational fluid dynamics, and the aerodynamic parameters that are difficult to be obtained by the traditional methods are obtained with software FLUENT. We also set up the mathematical model of the solenoid valve, including the aerodynamic model, the circuit model, the magnetic circuit model and the mechanical motion model. The calculation is completed in the Simulink, and the results of the calculation are analyzed. A set of the solenoid valve response characteristic test system is built, and the response characteristic parameters such as response time and maximum action frequency of the solenoid valve are tested. The experimental results are verified by comparing them with the simulation results. The final result shows that the response characteristics are basically irrelevant to the action frequency at a suitable working frequency. The open switching time of the solenoid valve decreases with the increase in the inlet pressure and the driving voltage and increases with the increase in the number of coil turns. The close switching time increases with the increase in the inlet pressure, the driving voltage and the number of coil turns.

scholarly journals FREON COOLING MINISYSTEM USING CIRCULAR MICRO-CHANNELS

2017 ◽  
Vol 20 (2) ◽  
Author(s):  
LILIANA PĂTULEANU ◽  
IOAN-COZMIN MANOLACHE-RUSU ◽  
TIBERIU BURDAN ◽  
FLORIN ANDRONIC ◽  
IVAN RADION
Keyword(s):  
Processing Speed ◽  
Heat Exchangers ◽  
Mechanical Compression ◽  
Refrigeration System ◽  
Electronic Components ◽  
Local Cooling ◽  
New Methods ◽  
Micro Channels ◽  
Nano Channel ◽  
Set Up

<p>The necessity of a higher data processing speed was crucial for the advances in computer science. There were created processors that needed increasingly more power, so that new methods were discovered and more complex systems were created in order to solve the cooling issue. In this paper, there are presented the trials performed on a mini refrigeration plant that used mechanical compression of Freon’s, designed to cool electronic components like microprocessors, microcontrollers, graphic stations, or in the case of local cooling in diverse areas such as bioengineering, optics and nanotechnologies. The refrigeration system was constructed as an experimental set-up and consists of the following: two mini heat exchangers, working both as a condenser and a vaporizer, which are made of circular micro channels, a refrigeration compressor, lamination valve which contains a circular nano channel and a micro filter. The experimental determinations have proven that, although such a system contains a small quantity of Freon, of the order of milligrams, it reaches temperatures of -44 °C.</p>

A Pilot Compressed Air Engine

2011 ◽  
Vol 22 (8) ◽  
pp. 1105-1113 ◽  
Author(s):  
Afzal Ahmed
Keyword(s):  
Motor Development ◽  
Fossil Fuel ◽  
Solenoid Valve ◽  
Compressed Air ◽  
Good News ◽  
Reciprocating Motion ◽  
Connecting Rod ◽  
History Of Development ◽  
History Of ◽  
Temperature And Pressure

The air car has a history of development - with proponents and critics - since 1687. As the conventional internal combustion car engine is only 20% efficient, it wastes a considerable amount of energy and will not be feasible, if - for whatever reasons - fossil fuel fall short in supply and therefore, extremely expensive. The drawback of an air engine is that, it is light, requires frequent refilling of the compressed air-tank even for short distances, and the temperature and pressure reduce during expansion in the cylinder. Current research is concerned with alleviating these drawbacks. The good news is that, Motor Development International (MDI) Luxembourg has developed an air engine for a car using a specially designed connecting rod. MDI is now building an air car of 75hp costing US $ 17,800.00 for US roads and can travel up to 1000 miles at 96 mph. In the present study, the concept of double acting steam engine is used by replacing steam with compressed air and the reciprocating motion of piston is governed through flywheel using a solenoid valve. The efficiency of the engine based on input energy of compressed air is about 80%.

Mathematical Analysis on a Special Adsorption Refrigeration System Suitable for Solar Energy System

2014 ◽  
Vol 953-954 ◽  
pp. 119-122
Author(s):  
Yan Ling Liu ◽  
Xue Zeng Shi ◽  
Yuan Yu
Keyword(s):  
System Performance ◽  
Energy System ◽  
Cooling Capacity ◽  
Refrigeration System ◽  
Adsorption Refrigeration ◽  
Study Results ◽  
Actual Use ◽  
Working Principle ◽  
Set Up ◽  
New System

s. In this paper, a new adsorption refrigeration system is designed and calculated. In this system, there are two beds, two condensers and two evaporators. The working principle is explained and specified in this paper. And mathematical models are also set up and through calculation, the system performance is analyzed and evaluated.Theory study results demonstrate that the new system nearly has the same cooling capacity as conventional system and this kind of system can be adopted in actual use.

scholarly journals Thermal Prospective Estimations of COP and TR for R12 and HR12 Vapour Compression Refrigeration Systems

2019 ◽  
Vol 9 (2) ◽  
pp. 897-902
Keyword(s):  
Performance Evaluation ◽  
Power Consumption ◽  
Linear Relationship ◽  
System Performance ◽  
Graphical Representation ◽  
Refrigeration System ◽  
Energy Meter ◽  
Temperature And Pressure ◽  
Vapour Compression ◽  
System Performance Evaluation

Experimentations got executed for investigating influence of R12 and HR12 refrigerants on system performance evaluation in terms of COP and TR. Temperature and pressure got measured by different temperature and pressure gauges mounted at several predetermined locations. Additionally, power consumption by refrigeration system also got measured from the installed energy meter readings. Altogether, it summarizes the tabular inscriptions of the variations of COPth, COPact and COPrel with TR for R12 and HR12 refrigerants. Besides, it also demonstrates the graphical representation of the corresponding variations of COPth, COPact and COPrel with TR for R12 and HR12 refrigerants. As expected, it stands observed (from both the stated table and figure) that both COPth and COPact increase with TR, however, the COPrel decreases with the same for said R12 and HR12 refrigerants. Furthermore, the stated variations of COPth, COPact and COPrel with TR remain observed as approximately linear, independently. That’s why, both COPth and COPact stay directly proportional to TR, however, the COPrel stays inversely proportional to the same because of approximately linear relationship between the COPth, COPact and COPrel with TR, individually. Additionally, COPact decreases with the increase of Wi/p for both R12 and HR12 refrigerants. However, Qext increases with Wi/p for both R12 and HR12 refrigerants.

Exploring experimental parameter choice for rapid speckle-tracking phase-contrast X-ray imaging with a paper analyzer

2015 ◽  
Vol 22 (5) ◽  
pp. 1279-1288 ◽  
Author(s):  
Isobel A. Aloisio ◽  
David M. Paganin ◽  
Christopher A. Wright ◽  
Kaye S. Morgan
Keyword(s):  
Real Time ◽  
Speckle Tracking ◽  
Phase Contrast ◽  
Experimental Parameter ◽  
Dynamic Imaging ◽  
Synchrotron Source ◽  
X Ray ◽  
Detector Distance ◽  
X Ray Imaging ◽  
Set Up

Phase-contrast X-ray imaging using a paper analyzer enables the visualization of X-ray transparent biological structures using the refractive properties of the sample. The technique measures the sample-induced distortions of a spatially random reference pattern to retrieve quantitative sample information. This phase-contrast method is promising for biomedical application due to both a simple experimental set-up and a capability for real-time imaging. The authors explore the experimental configuration required to achieve robustness and accuracy in terms of (i) the paper analyzer feature size, (ii) the sample-to-detector distance, and (iii) the exposure time. Results using a synchrotron source confirm that the technique achieves accurate phase retrieval with a range of paper analyzers and at exposures as short as 0.5 ms. These exposure times are sufficiently short relative to characteristic physiological timescales to enable real-time dynamic imaging of living samples. A theoretical guide to the choice of sample-to-detector distance is also derived. While the measurements are specific to the set-up, these guidelines, the example speckle images, the strategies for analysis in the presence of noise and the experimental considerations and discussion will be of value to those who wish to use the speckle-tracking paper analyzer technique.

Condensing Heat Recovery of Existing Large-Scale Refrigeration System

2012 ◽  
Vol 214 ◽  
pp. 136-140
Author(s):  
Da Yu Zheng ◽  
Bing Guo ◽  
Wei Dang Liu ◽  
Xin Chen
Keyword(s):  
Heat Recovery ◽  
Large Scale ◽  
Waste Heat ◽  
Cooling Water ◽  
Operating Conditions ◽  
Hot Water ◽  
Refrigeration System ◽  
Recovery Unit ◽  
Temperature And Pressure ◽  
System Operating

Existing refrigeration systems generally put the high temperature and pressure of refrigerant vapor into the atmosphere or cooling water through the condenser to reach the purpose of condensing refrigerant. But this will lead to the environment “thermal pollution”, and a waste of energy. This paper describes a plan of modification of the existing refrigeration system, through the waste heat recovery unit can be recovered the condensing heat effectively and product hot water in 50~ 60 to provide bathing. This system also can improve the refrigeration system operating conditions and the efficiency of generating units to achieve the purpose of energy saving.

The Characteristics of CO2 Flow and Thermal Field in a Porous Media

2010 ◽  
Author(s):  
Hang Seok Choi ◽  
Yeon Seok Choi ◽  
Hoon Chae Park ◽  
Cheol Huh ◽  
Seong-Gil Kang ◽  
...  
Keyword(s):  
Porous Structure ◽  
Co2 Storage ◽  
Co2 Injection ◽  
Physical Conditions ◽  
Thermal Fields ◽  
Level Model ◽  
Temperature And Pressure ◽  
Set Up ◽  
Co2 Flow ◽  
And Storage

International attention has been considerably paid for the technology of CO2 capture and storage (CCS) these days because of global warming. Among the technologies of CCS, the prediction of CO2 behavior in underground is very crucial for CO2 storage design. In the present study, a pore-scale level model is developed to mimic real porous structure and by using CFD (computational fluid dynamics) the characteristics of the CO2 flow and thermal fields are investigated in the pore-level micro porous structure. Varying the CO2 injection conditions such as flow rate, pressure and temperature, the behavior of CO2 is calculated. Especially, the physical conditions such as temperature and pressure are set up equivalent to the underground condition at which CO2 is injected. From the results, the injection condition of CO2 is very critical to the characteristics of the flow and thermal fields in the micro-scale porous structure.

scholarly journals Exergy and Exergoeconomic Analysis of a Cogeneration Hybrid Solar Organic Rankine Cycle with Ejector

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 702
Author(s):  
Bourhan Tashtoush ◽  
Tatiana Morosuk ◽  
Jigar Chudasama
Keyword(s):  
Electrical Power ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Temperature And Pressure

Solar energy is utilized in a combined ejector refrigeration system with an organic Rankine cycle (ORC) to produce a cooling effect and generate electrical power. This study aims at increasing the utilized share of the collected solar thermal energy by inserting an ORC into the system. As the ejector refrigeration cycle reaches its maximum coefficient of performance (COP), the ORC starts working and generating electrical power. This electricity is used to run the circulating pumps and the control system, which makes the system autonomous. For the ejector refrigeration system, R134a refrigerant is selected as the working fluid for its performance characteristics and environmentally friendly nature. The COP of 0.53 was obtained for the ejector refrigeration cycle. The combined cycle of the solar ejector refrigeration and ORC is modeled in EBSILON Professional. Different parameters like generator temperature and pressure, condenser temperature and pressure, and entrainment ratio are studied, and the effect of these parameters on the cycle COP is investigated. Exergy, economic, and exergoeconomic analyses of the hybrid system are carried out to identify the thermodynamic and cost inefficiencies present in various components of the system.

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