Investigation on the Optimum Performance of an Irreversible Solar Powered Absorption Refrigeration System

2011 ◽  
Author(s):  
Fang Wei ◽  
Houcheng Zhang ◽  
Lanmei Wu ◽  
Guoxing Lin
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Solar Collector ◽  
Optimal Parameter ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Absorption Refrigeration System ◽  
Solar Powered

An irreversible solar powered absorption refrigeration system is put forward, in which finite-rate heat transfer with the convection mode from the solar collector to the absorption refrigerator and the radiation-convection heat loss from the solar collector to the ambient, the internal irreversibility inside the working fluid are taken into account. On the basis of thermodynamic analysis and log mean temperature difference (LMTD) methods, the expression between the overall coefficient of performance (COP) of the solar powered absorption refrigeration system and the operating temperature of the solar collector is derived. The influences of heat loss of the solar collector, the irreversibility inside the working fluid, the isobaric temperature ratio, the ratio of heat-transfer coefficients on the optimal performance characteristic of the solar powered absorption refrigeration system are revealed. The results obtained in the present paper are helpful to the optimal parameter design of actual solar powered absorption refrigerators.

Waste-Heat Driven Miniature Absorption Refrigeration System Using Ionic-Liquid as a Working Fluid

2011 ◽  
Author(s):  
Yoon Jo Kim ◽  
Sarah Kim ◽  
Yogendra K. Joshi ◽  
Andrei G. Fedorov ◽  
Paul A. Kohl
Keyword(s):  
Ionic Liquid ◽  
Waste Heat ◽  
Coefficient Of Performance ◽  
System Level ◽  
Working Fluid ◽  
Operating Efficiency ◽  
Outlet Temperature ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Absorption Refrigeration System

An ionic-liquid (IL) is a salt in a liquid state usually with an organic cation and inorganic anion. ILs provide an alternative to the normally toxic working fluids in absorption systems, such as the ammonia/water system. They also eliminate the problems of poor temperature match, crystallization and metal-compatibility problems of the water/LiBr system. In the present study, an IL is explored the working fluid of a miniature absorption refrigeration system so as to utilize waste-heat within the system for low-cost, high-power electronics cooling. To determine performance benchmarks for the refrigerant/IL (e.g. [bmim][PF6]) pairs, system-level simulations have been carried out. An NRTL model was built and used to predict the solubility of the mixture as well as the mixture properties such as enthalpy and entropy. The properties of the refrigerants were determined using REFPROP 6.0. Saturation temperatures at the evaporator and condenser were 25°C and 50°C, respectively. Chip power was fixed at 100 W with the operating temperature set at 85°C. R32 gave the highest operating efficiency with the maximum coefficient of performance (COP) of ca. 0.55 while R134a and R152a showed comparable performance with the maximum COP of ca. 0.4 at the desorber outlet temperature of 80°C. When waste-heat is available for the system operation, R134a and R152a COPs were comparable or better than that of R32.

Thermodynamic Modeling and Performance Optimization of a Solar-Assisted Vapor Absorption Refrigeration System (SAVARS)

2020 ◽  
Vol 28 (01) ◽  
pp. 2050006
Author(s):  
Boris Huirem ◽  
Pradeepta Kumar Sahoo
Keyword(s):  
Performance Optimization ◽  
Fruits And Vegetables ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Absorption Refrigeration ◽  
Performance Parameters ◽  
Refrigeration System ◽  
Vapor Absorption ◽  
Absorption Refrigeration System ◽  
Vapor Absorption Refrigeration

A thermodynamic steady-state model for a single-effect lithium bromide–water (LiBr-H2O)-based vapor absorption refrigeration system of 17.5[Formula: see text]kW capacities has been presented using the first and second laws of thermodynamics. The mass, energy and exergy balance equations in each component of the vapor absorption cycle have been fitted into a computer program to carry out the calculation using the thermo-physical properties of the working fluid. The performance parameters such as coefficient of performance (COP), exergy coefficient of performance (ECOP), total exergy destruction (TED), etc. have been evaluated considering different temperatures in generator and evaporator, different LiBr concentrations in the weak and strong LiBr-H2O solution and different solution heat exchanger effectiveness. The model evaluated the optimum performance parameters like COP, ECOP, TED, etc. of the vapor absorption system by using Design Expert-12 software for an application like on-farm cooling or transit storage of fruits and vegetables.

scholarly journals TESTS OF ARRANGEMENTS IN A PROTOTYPE OF A STEAM GENERATOR IN AN ABSORPTION REFRIGERATION SYSTEM

2019 ◽  
Vol 18 (2) ◽  
pp. 70
Author(s):  
R. F. M. Santos ◽  
K. L. Cezar ◽  
P. A. C. Rocha ◽  
R. J. P. Lima ◽  
M. E. V. da Silva ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Steam Generator ◽  
Lithium Bromide ◽  
Heat Transfer Process ◽  
Heat Flow Rate ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Governing Factor ◽  
Absorption Refrigeration System ◽  
Internal Convection

This paper presents a proposal to optimize the prototype II of a steam generator, developed by the Cooperativa de Pesquisa Norte/Nordeste de Gas Natural, RECOGÁS - UFPB, which is a component of an absorption refrigeration system of water and lithium bromide triggered by direct burning of natural gas. The optimization was carried out through changes in the arrangement, geometry, and number of the heat exchanger pipes. It was developed a computational code using F-Chart software Engineering Equation Solver® (EES), applying the principles of heat transfer to all the different geometries. As a result, their respective coefficients of heat transfer, heat flow rate and other parameters of the process were obtained. The findings are organized in a table and represented in graphs generated by the EES software, allowing to verify which factors had a greater influence on the process, as well as the most efficient geometries. Internal convection was identified as the governing factor in the heat transfer process. Some of the geometries presented satisfactory values to the product of overall heat transfer coefficient and surface area (UA) and also to the heat transfer rate in the steam generator. Other ones presented a better thermal efficiency relation with the amount of volume occupied in the steam generator. Some geometries did not present satisfactory values under any aspect.

Performance Optimization and Parametric Analysis of a Class of Solar-Driven Heat Engines

2010 ◽  
Author(s):  
Houcheng Zhang ◽  
Lanmei Wu ◽  
Guoxing Lin
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Performance Optimization ◽  
Solar Collector ◽  
Heat Engine ◽  
Working Fluid ◽  
Convection Heat ◽  
Combined System ◽  
Heat Engines ◽  
Internal Irreversibility

A class of solar-driven heat engines is modeled as a combined system consisting of a solar collector and a unified heat engine, in which muti-irreversibilities including not only the finite rate heat transfer and the internal irreversibility, but also radiation-convection heat loss from the solar collector to the ambience are taken into account. The maximum overall efficiency of the system, the optimal operating temperature of the solar collector, the optimal temperatures of the working fluid and the optimal ratio of heat transfer areas are calculated by using numerical calculation method. The influences of radiation-convection heat loss of the collector and internal irreversibility on the cyclic performances of the solar-driven heat engine system are revealed. The results obtained in the present paper are more general than those in literature and the performance characteristics of several solar-driven heat engines such as Carnot, Brayton, Braysson and so on can be directly derived from them.

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