کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
243509 501930 2012 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Study of an ejector-absorption refrigeration cycle with an adaptable ejector nozzle for different working conditions
موضوعات مرتبط
مهندسی و علوم پایه مهندسی انرژی مهندسی انرژی و فناوری های برق
پیش نمایش صفحه اول مقاله
Study of an ejector-absorption refrigeration cycle with an adaptable ejector nozzle for different working conditions
چکیده انگلیسی

This paper presents a numerical model of an ejector-absorption (single-effect) refrigeration cycle with ammonia–lithium nitrate solution as working fluid, operating under steady-state conditions. In this cycle, the ejector is located at the absorber inlet replacing the solution expansion valve. The liquid–gas ejector entrains refrigerant vapor from the evaporator; this way the absorber pressure becomes higher than the evaporator pressure without any additional energy consumption. The objective of this numerical model is to evaluate the influence of the ejector geometry on the cycle performances and to determine the range of the heat source temperature in which it is convenient to use a practical ejector in the absorption cycle. The simulation is based on UA-ΔTlm models for separate heat transfer regions in a novel implementation using plate-type heat exchangers and this way the results are offered as a function of the external temperatures. This study focuses on evaluating the feasibility of an ejector whose nozzle area is adjustable while the rest of the ejector dimensions are fixed, thus being more feasible than complete variable geometry ejectors. The cycle performance is reported for different mixing tube constant diameters. Results of the simulation show that the use of an ejector allows, among others, to decrease the activation temperature approximately 9 °C in respect to the conventional single-effect absorption cycle and increasing the COP for moderate temperatures. The variable ejector nozzle geometry is of profit for optimizing and controlling the cycle.


► An absorption refrigeration cycle with an ejector device at the absorber inlet is presented.
► This cycle is able to reduce up to 9 °C the temperature of onset of refrigerant generation without extra energy consumption.
► At very low driving temperatures it allows increasing the cooling capacity.
► The ejector device proposed has a partially variable geometry and we study its influence on the cycle performances.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Energy - Volume 97, September 2012, Pages 305–312
نویسندگان
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