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:

The Miniaturization of a Refrigeration Vapor Compression System and Application to the Cooling of High Power Microelectronics

2006 ◽  
Author(s):  
Victor Chiriac ◽  
Florin Chiriac
Keyword(s):  
High Power ◽  
Cooling System ◽  
Real Life ◽  
System Level ◽  
Small Scale ◽  
Vapor Compression ◽  
Mechanical Compression ◽  
Refrigeration System ◽  
Compression System ◽  
Vapor Compression System

The study develops an analytical model of an optimized small scale refrigeration system using ejector vapor compression, with application to the cooling of the electronic components populating a Printed Circuit Board (PCB) in a High-Power Microelectronics System. The authors' previous studies [1 - 3] evaluated a vapor compression system using an off-the-shelf mechanical compressor and associated components, focusing mainly on the thermal feasibility of the mechanical refrigeration system and on-chip system-level incorporation. Present investigation focuses on the miniaturization of the various components of the vapor compression system (targeting the alternative ejector vapor compressor), with the intent to establish a cooling system for high power microelectronics, designed to fit smaller packages populating PCB, yet using a different approach for the vapor compression process. The previous study [1] evaluated several optimized evaporator designs for the mechanical compression system. The current design with miniaturized ejector is evaluated to address similar power dissipation ranges as before. In the final section of the study, the efficiency of the proposed ejector vapor compression system is compared to mechanical compression designs at same cooling powers. It is the intent of the authors to present an alternative vapor compression system and identify the pros and cons of implementing such a system to real-life microelectronics applications.

scholarly journals Modeling and Simulation of a Desiccant Evaporative Cooling System

2019 ◽  
Vol 26 (3) ◽  
pp. 10-18
Author(s):  
Omar M. Hamdoon ◽  
Burhan M. Al-Ali
Keyword(s):  
Cooling System ◽  
Vapor Compression ◽  
Air Conditioning System ◽  
Climate Conditions ◽  
Compression System ◽  
Evaporative Cooling System ◽  
Vapor Compression System ◽  
Three Stages ◽  
Simulation Results ◽  
System Operating

This paper studies the performance of a proposed desiccant assisted air conditioning system operating under the hot and dry climate conditions of Mosul city, Iraq. The proposed system consists of three stages: indirect/direct evaporative cooler, an enthalpy wheel, and a traditional vapor compression system. The performance of the suggested system is compared with that of the vapor compression system operating at the same conditions. The simulation results showed that an optimum rotational speed of 12.5 rpm is required for the enthalpy wheel to achieve the best system performance. The simulation results also showed the ability of the proposed system to achieve a power consumption saving of 51.03%, in the ventilation mode, and 22.93%, in the mixing mode with a ventilation mixing ratio of 0.4 when compared to the vapor compression system.

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.

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

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.

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.

Comparative Analysis of Vapor Compression and Hybrid Liquid Desiccant Dehumidification Systems

2005 ◽  
Author(s):  
A. M. Al-Jaafari ◽  
S. A. Sherif
Keyword(s):  
Energy Savings ◽  
Cooling System ◽  
The United States ◽  
Normal Operation ◽  
Weather Data ◽  
Energy Calculation ◽  
Vapor Compression ◽  
Liquid Desiccant ◽  
Study Results ◽  
Vapor Compression System

The objective of this study was to evaluate the energy savings of a commercially available hybrid liquid desiccant (HLD) cooling system relative to a conventional vapor compression system used for an existing school building where 100% outside air is used for ventilation. Psychrometric analysis and hour-by-hour simulations for three energy models were developed for three cities in the United States using available weather data assuming normal operation and typical building occupancy. Energy calculation software such as the Carrier Hourly Analysis Program (HAP 4.1) and Desicalc along with generated spreadsheets was used to compute the energy consumption for the models under study. Results of each model are summarized and comparisons are made. The annual energy savings employing the HLD system were found to reach 46% for Chicago, 37% for Gainesville and 32% for Miami. Simple cost analysis and associated payback periods were also performed.

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