Experimental Investigation of Ejector-Assisted Vapor Compression System

2019 ◽  
Vol 27 (03) ◽  
pp. 1950029
Author(s):  
Vikas Kumar ◽  
Gulshan Sachdeva
Keyword(s):  
Capillary Tube ◽  
Area Ratio ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Evaporator Temperature ◽  
Compression System ◽  
Wide Range ◽  
Expansion Valve ◽  
Maximum Improvement ◽  
Vapor Compression System

The performance of an ejector as an expansion device rather than the conventional expansion valve or capillary tube in a vapor compression system is experimentally analyzed. Experiments have been conducted using 28 ejectors of different dimensions at the same condenser and evaporator temperatures, and it has been observed that for utmost performance, an optimum area ratio of the ejector is required. One of the ejector geometry has been experimented further for a wide range of condenser and evaporator temperatures. The coefficient of performance is found to be enhanced by at least 10% in comparison to the conventional vapor compression system for the considered range of condenser and evaporator temperatures and the maximum improvement in COP obtained is 12.83% at 14.3∘C evaporator temperature and 32.4∘C condenser temperature with 17.9211 ejector area ratio. The refrigerant R134a has been used as the working substance.

An Experimental Investigation on Vapor Compression Refrigeration System Cascaded with Ejector Refrigeration System

2021 ◽  
pp. 2150028
Author(s):  
Vikas Kumar ◽  
Gulshan Sachdeva ◽  
Sandeep Tiwari ◽  
Parinam Anuradha ◽  
Vaibhav Jain
Keyword(s):  
Experimental Investigation ◽  
Thermal Equilibrium ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Compression System ◽  
Vapor Compression System ◽  
Vapor Compression Refrigeration ◽  
Cascaded System

A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.

Optimized Refrigerant Flow Rate and Dimensions of the Ejector Employed in a Modified Ejector Vapor Compression System

2020 ◽  
Vol 28 (04) ◽  
pp. 2050038
Author(s):  
Dishant Sharma ◽  
Gulshan Sachdeva ◽  
Dinesh Kumar Saini
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Vapor Compression ◽  
Evaporator Temperature ◽  
Proposed Model ◽  
Condenser Temperature ◽  
Vapor Compression System ◽  
Vapor Compression Cooling

This paper presents the analysis of a modified vapor compression cooling system which uses an ejector as an expansion device. Expanding refrigerant in an ejector enhances the refrigeration effect and reduces compressor work. Therefore, it yields a better coefficient of performance. Thermodynamic analysis of a constant area ejector model has been done to obtain primary dimensions of the ejector for given condenser and evaporator temperature and cooling capacity. The proposed model has been used to design the ejector for three refrigerants; R134a, R152a and R1234yf. The refrigerant flow rate and the diameters at various sections of the ejector have been obtained by doing numerical modeling in Engineering Equation Solver (EES). Refrigerant R1234yf demanded the highest diameter requirements at a fixed 5∘C evaporator temperature and 40∘C condenser temperature for a given range of cooling load. Both primary and secondary refrigerants flow rates are higher for R1234yf followed by R134a and then R152a.

scholarly journals Influence of electronic expansion valve on the performance of small window air conditioner retrofitted with R407C and R290

2011 ◽  
Vol 15 (suppl. 2) ◽  
pp. 327-339 ◽  
Author(s):  
Chennuchetty Chinnaraj ◽  
Palanisamy Govindarajan ◽  
Raghavan Vijayan
Keyword(s):  
Control Method ◽  
Capillary Tube ◽  
Coefficient Of Performance ◽  
Air Conditioner ◽  
Wide Range ◽  
Advanced Control ◽  
Expansion Valve ◽  
Compressor Inlet ◽  
Potential Alternative ◽  
Flow Through

The objective of this study is to investigate the influence of Electronic Expansion Valve (EEV) on the performance of window air conditioner retrofitted with R407C and R290. The window air conditioner applying the EEV is tested by varying the compressor inlet superheat from 0?C to 20?C. The eco friendly refrigerant R407C has the similar thermodynamic properties as those of R22 with an exception of temperature gliding during the phase change at constant pressure. R290 is a hydrocarbon which also exhibits properties very close to R22 which enables this to be used as a potential alternative to R22.The EEV affords a precise, fast, and stable flow control for a wide range of flow rate due to its use of an electronic control method based on an advanced control algorithm.EEV controls the refrigerant flow through the evaporator by means monitoring pressure and temperature at the outlet of the evaporator and hence it shows good overall performances comparing the capillary tube system. The Coefficient of Performance (COP) of R290 is the maximum among the three refrigerants tested and also for all the three refrigerants, COP is low at higher degree of superheat.

Study on Conceptual Design of a Solar Ejector Refrigeration System

2020 ◽  
Vol 28 (01) ◽  
pp. 2030001 ◽  
Author(s):  
Md. Khairul Bashar Shovon ◽  
Raman Senthil Kumar ◽  
Tae Ho Kim ◽  
Heuy Dong Kim
Keyword(s):  
Working Conditions ◽  
Renewable Energy Sources ◽  
Area Ratio ◽  
Coefficient Of Performance ◽  
Energy Sources ◽  
Refrigeration System ◽  
Critical Mode ◽  
Evaporator Temperature ◽  
Critical System ◽  
Wide Range

The refrigeration system based on the conventional compression cycle consumes an enormous amount of high-grade energy. Using fossil fuels as the energy sources results in the addition of CO2 into the atmosphere and consequently stimulating higher greenhouse effect. The ejector refrigeration systems powered by renewable energy sources would be an effective alternative without increasing global CO2 footprint. In this study, the performance characteristics of a solar ejector refrigeration system working with R718 are analytically calculated by using a one-dimensional flow model. At the critical mode, the solar ejector-refrigeration system is analyzed at various working conditions such as condenser temperature, evaporator temperature, generator temperature, and ejector area ratio. The critical system performance is analyzed to meet any designated working conditions with a wide range of condenser temperatures. It is found that during the critical mode of operation, higher area ratio, higher evaporator temperature and lower generator temperature enhance the performance of the system. The minimum evaporator temperature, and the maximum generator temperature designed to acquire the required coefficient of performance value are also calculated.

Miniature Vapor Compression Refrigeration Systems for Active Cooling of High Performance Computers

2001 ◽  
Author(s):  
Ali Heydari ◽  
Kathy Russell
Keyword(s):  
Heat Exchanger ◽  
High Performance ◽  
Capillary Tube ◽  
New Technology ◽  
Mathematical Formulation ◽  
Coefficient Of Performance ◽  
Simulation Program ◽  
Vapor Compression ◽  
Refrigeration System ◽  
System Components

Abstract A small refrigeration system for cooling of computer system components is evaluated. A thermodynamic model describing the performance of the cycle along with a computer simulation program is developed to evaluate its performance. The refrigeration system makes use of a miniature reciprocating vapor compression compressor. Due to space limitations in some high performance computer servers, a miniature refrigeration system composed of a compressor, capillary tube, a compact condenser, and a cold-plate evaporator heat exchanger are used. Mathematical multi-zone formulation for modeling thermal-hydraulic performance of heat exchanger for the condenser and evaporator are presented. The throttling device is a capillary tube and there is presented a mathematical formulation for predicting refrigerant mass flow rate through the throttling device. A physically based efficiency formulation for simulating the performance of the miniature compressor is used. An efficient iterative numerical scheme with allowance for utilization of various refrigerants is developed to solve the governing system of equations. Using the simulation program, the effects of parameters such as the choice of working refrigerant, evaporating and condensing temperatures on system components and overall efficiency of system are studied. In addition, a RAS (reliability, availability and serviceability) discussion of the proposed CPU-cooling refrigeration solution is presented. The results of analysis show that the new technology not only overcomes many shortcomings of the traditional fan-cooled systems, but also has the capacity of increasing the cooling system’s coefficient of performance.

A review on the operational instability of vapor compression system

2021 ◽  
Vol 122 ◽  
pp. 97-109
Author(s):  
Yudong Xia ◽  
Qiang Ding ◽  
Nijie Jing ◽  
Aipeng Jiang ◽  
Xuejun Zhang ◽  
...  
Keyword(s):  
Vapor Compression ◽  
Compression System ◽  
Vapor Compression System

Thermoelectric Heat Pipe-Based Refrigerator: System Development and Comparison with Thermoelectric, Absorption and Vapor Compression Refrigerators

2013 ◽  
Vol 651 ◽  
pp. 736-744
Author(s):  
Nandy Putra ◽  
H. Ardiyansya ◽  
Ridho Irwansyah ◽  
Wayan Nata Septiadi ◽  
A. Adiwinata ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Heat Dissipation ◽  
System Development ◽  
Coefficient Of Performance ◽  
Prototype System ◽  
Vapor Compression ◽  
Thermoelectric Coolers ◽  
Thermoelectric Systems ◽  
Vapor Compression System ◽  
Thermoelectric Heat

Thermoelectric coolers have been widely applied to provide cooling for refrigerators in addition to conventional absorption and vapor compression systems. To increase heat dissipation in the thermoelectric cooler’s modules, a heat pipe can be installed in the system. The aim of this study is to develop a thermoelectric heat pipe-based (THP) refrigerator, which consists of thermoelectric coolers that are connected by heat pipe modules to enhance heat transfer. A comparative analysis of the THP prototype and conventional refrigerator with vapor compression, absorption and thermoelectric systems is also presented. The prototype system has a faster cooling down time and a higher coefficient of performance than the absorption system but still lower than vapor compression system

A New Approach to Exergy Analyses of a Hybrid Desiccant Cooling System Compares to a Vapor Compression System

2011 ◽  
Vol 110-116 ◽  
pp. 2163-2169
Author(s):  
S. Khosravi ◽  
Yat Huang Yau ◽  
T.M.I. Mahlia ◽  
M.H. Saidi
Keyword(s):  
Indoor Air ◽  
Cooling System ◽  
Vapor Compression ◽  
Cooling Systems ◽  
New Approach ◽  
Compression System ◽  
Humid Condition ◽  
Economical System ◽  
Vapor Compression System ◽  
Exergy Analyses

In the recent researches HVAC with a based desiccant dehumidifier with a low ambient impact is more efficient in comparison to the traditional systems. Hybrid desiccant cooling systems can be used to control indoor air quality in buildings. This paper presents an integrated energy, entropy and exergy analysis of a hybrid desiccant cooling system compare to a compression system based on first and second laws of thermodynamic. The main objective is the use of a method called exergy costing applied to a conventional compression system that has been chosen to provide the proper conditioned air for a building in hot and humid condition. By applying the same method for the equivalent hybrid cooling system and finding the same exergy costing parameters, two systems can be in comparison to find the more economical system. The result illustrated hybrid desiccant cooling system can be providing 19.78% energy saving and 14.5% cheaper than the compression system the same capacity and lifetime. Nomenclature:

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