Thermodynamic and exergy analysis of thermal System

Abstract

In the thesis, the refrigeration and air-conditioning systems having low carbon emission newlineand eco-friendly relationship have been examined and evaluated. An attempt has been newlinemade to synthesise the vapour compression and absorption cycles for the investigation of newlineenergy and exergy performance. newlineThe subcooling methods viz. liquid vapour heat exchanger incorporation to vapour newlinecompression refrigeration (VCR) system and dedicated mechanical subcooled VCR newlinesystem have been investigated using R134a and alternate refrigerants R1234yf and newlineR1234ze. An experimental VCR setup has also compared to simple theoretical VCR newlinesystem in order to examine the performance and compatibility of alternative refrigerants. newlineThe results depict that the subcooling methods improve coefficient of performance (COP) newlineand exergy efficiency of the VCR system. The performance of R1234ze is better than that newlineof R1234yf and it competes with R134a. newlineThe low grade energy (waste heat) available at temperature (i.e. within 60-2000C) is newlineutilized as source in the various cascade configurations of vapour compressionabsorption newlinerefrigeration cycles. The objectives of the present work are reduction in high newlinegrade energy (electrical energy) consumed by the compressor consequently, reduction in newlinecarbon emission and global warming potential. Simultaneously, the cascading effect newlineproduces lower temperature for the deep freezing and chilling applications. newlineFor achieving the dual objectives, the energy and exergy analysis of absorptioncompression newlinecascade refrigeration cycles along with wide range of parametric analysis newlinehave been carried out by developing engineering equation solver (EES) software based newlinecomputer programs. newlineThe waste heat available at higher temperature (165-2000C) has been utilized in newlinecompression-absorption (triple effect series flow H2O-LiBr) cascade refrigeration cycle newlinewhile the low temperature (65-950C) waste heat has been utilized in compression absorption newline(single and half effect series flow H2O-LiBr) cascade refrigeration cycle.