Energy Conversion and Management 224 (2020) 113348 Available online 21 August 2020 0196-8904/© 2020 Elsevier Ltd. All rights reserved. Advanced exergy analysis and risk estimation of novel NH 3 -H 2 O and H 2 O-LiBr integrated vapor absorption refrigeration system Vaibhav Jain a, * , Ashu Singhal b , Gulshan Sachdeva c , S.S. Kachhwaha d a Department of Mechanical Engineering, MAIT, Delhi, India b Department of Mechanical and Automation Engineering, MAIT, Delhi, India c Department of Mechanical Engineering, National Institute of Technology, Kurukshetra, India d Department of Mechanical Engineering, Pandit Deendayal Petroleum University, Gujarat, India A R T I C L E INFO Keywords: NH 3 -H 2 O and H 2 O-LiBr integrated refrigeration system CSB Pareto chart Advanced exergy analysis Total risk level ABSTRACT In present work, thermodynamic potential and risk estimation of NH 3 -H 2 O and H 2 O-LiBr integrated vapor ab- sorption refrigeration system (IVARS) have been reported. The performance of IVARS has also been compared with a conventional vapor absorption refrigeration system (VARS) for the same cooling duty. Comparative results show that the proposed confguration can maintain evaporator temperature of 30 ◦ C with 92.1 ◦ C generator temperature, which is 51.6 ◦ C lower than that required in a conventional VARS. Further, coeffcient of structural bonds (CSB) values predict that the solution heat exchanger of NH 3 -H 2 O subsystem (maximum CSB value 5.28) is the most sensitive heat exchanger; whereas, generator of H 2 O-LiBr subsystem (minimum CSB value 0.38) is the most effcient heat exchanger of IVARS, but contrary to this, their involvement in total irreversibility is merely 6.7% and 18.6% respectively. Based on 80/20 principle, Pareto chart suggests the designer to focus on improving the effciency parameter of generators and absorbers of IVARS due to their signifcant contribution in total irreversibility rate. Hence, advanced exergy analysis has been performed to overcome this dilemma. Interest- ingly, 19.8% of the irreversible loss in IVARS is found avoidable and can be eradicated by modifying the eff- ciency parameters of different components of IVARS and 93.7% of irreversibility rate is due to the selected operating parameters of components itself. Moreover, the total annual risk due to toxic fuid ‘ammonia’ in NH 3 - H 2 O absorption subsystem is estimated to be US$ 996.6/year and the condenser of NH 3 -H 2 O is found to be the major contributor. Present study shows that IVARS has better thermodynamic performance and can be suc- cessfully operated using low temperature waste heat with effcient and effective recovery. 1. Introduction A broad range of evaporator temperature is required in the cooling systems depending up on their applications [1]. Vapor compression refrigeration system (VCRS) and vapor absorption refrigeration system (VARS) are widely used to meet this requirement. However, VCRS is more in demand than VARS because of its high COP and small volume as compared to VARS. But the operational cost of VCRS is much higher than VARS as VCRS needs a high grade energy for its operation (electric power) [2]. On the other side, VARS requires mainly low grade energy for its operation, which can be easily managed using renewable re- sources, geothermal energy, waste heat after industrial progression etc. VARS is an effcient and sustainable cooling technique with waste heat recovery [3–4] and often termed as ‘future cooling technique’ for energy conservation. The VARS can effectively recover and reprocess huge amount of waste heat [5]. A number of researchers [6–8] have examined the realization of VARS taking H 2 O-LiBr as a fuid pair. It is ordinarily used for air- conditioning applications, since it can provide the evaporator temper- ature upto 5 ◦ C [9]. For operations of lower than 5 ◦ C, fuid pair of NH 3 - H 2 O is successfully employed in VARS [10]. Further, researchers re- ported that H 2 O-LiBr working pair in VARS yields better results than NH 3 -H 2 O combination in terms of energy and exergy analyses. Cimsit and Ozturk [11] demonstrated that heat load in the generator of VARS was decreased by 35% with H 2 O-LiBr working pair. Hence, COP was upgraded to 33% in comparison with NH 3 -H 2 O working pair. Also, second law analysis by Cimsit et al. [12] displayed 20% less irrevers- ibility rate in the system with H 2 O-LiBr working pair in comparison with NH 3 -H 2 O pair. Majority of the studies on VARS aim to improve its * Corresponding author. E-mail address: vaibhavursaathi@gmail.com (V. Jain). Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman https://doi.org/10.1016/j.enconman.2020.113348 Received 17 June 2020; Received in revised form 13 August 2020; Accepted 14 August 2020