Energy Conversion and Management 223 (2020) 113328 Available online 4 September 2020 0196-8904/© 2020 Elsevier Ltd. All rights reserved. Pinch and exergy evaluation of Kalina/Rankine/gas/steam combined power cycles for tri-generation of power, cooling and hot water using liquefed natural gas regasifcation Bahram Ghorbani a, * , Armin Ebrahimi b , Sajedeh Rooholamini a , Masoud Ziabasharhagh b a Faculty of Engineering Modern Technologies, Amol University of Special Modern Technologies, Amol, Iran b Faculty of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran A R T I C L E INFO Keywords: Process integration LNG regasifcation Low-temperature organic Rankine cycle Power generation combined plant Kalina power cycle Exergy and pinch analyses ABSTRACT Today, due to the increasing trend of energy demand in the world, the use of energy types with the approach of maximizing the effciency of energy systems is inevitable. In this paper, an integrated power generation system consisting of low-temperature organic Rankine cycle, gas and steam combined power plant and Kalina power generation unit is developed and analyzed. Liquefed natural gas regasifcation is employed to supply the cooling for the hybrid system. This integrated system generates 158.5 MW power, 9.498 MW cooling, and 46.02 kg/s hot water. The total electrical, thermal, and exergy effciencies of the integrated system are 48.62%, 55.18% and 67.74%, respectively. System exergy analysis shows that reactors and heat exchangers accounted for the largest share of total exergy destruction, each accounting for 59.91% and 15.76% of total energy destruction, respec- tively, indicating that these two parts have more than 75% of the destruction occurred. The pinch method was used to extract the heat exchanger network related to the multi-stream heat exchanger of the integrated system. In the parametric analysis, the effect of air/fuel molar ratio (input to the combustion chamber) on system per- formance has been investigated. One of the most important results is the increase in the total thermal effciency of the system to 56.15% if the inlet air into the combustion chamber is reduced to 250.0 kg/s. The parametric analysis results also show that in addition to increasing the effciency of the system due to the decrease in the amount of incoming air, the ratio of power production as the main product to byproducts (hot water and cooling) increases. 1. Introduction With increasing energy consumption all over the world, fnding high- effcient energy sources and systems is necessary. Natural gas (NG) is a fossil fuel with low amounts of carbon that due to less contamination compared with other fossil fuels is interested [1]. Nowadays, NG has the cleanest combustion that supplying about 25% of energy demands. It is estimated that energy demand increases by about 1.6% per year be- tween 2016 and 2035 [2,3], and NG is only fossil fuel that has increasing demands [3]. Due to the unbalanced distribution of NG resources in the world, usually NG is transported to the fnal terminal by pipelines. Long- distance transportation by pipeline causes a gas pressure drop. This pressure drop has unfavorable effects on gas transportation. The only feasible way to the transportation of NG from the importer country to the gas consumers is NG liquefaction [4]. LNG (Liquefed natural gas) regasifcation is the fnal step in the LNG supply chain, and wasted energy of LNG regasifcation operation can be used in low power gen- eration cycles [5]. There are four conventional technologies for the regasifcation of LNG: Open Rack Vaporizer (ORV) [6], Submerged Combustion Vaporizer (SCV) [7], ambient air-based Heating Vaporizer (AHV) [8] and Intermediate Fluid Vaporizer (IFV) [9]. LNG cold energy recovery has three advantages: (1) LNG cold energy recovery to increase energy effciency, (2) energy saving with avoiding consuming extra LNG for regasifcation, and (3) reduction of the environmental impact [10]. The temperature difference between ambient (or seawater) and LNG about 182 K can utilize directly or utilize to electrical power generation [11]. The direct applications of this cold energy include air separation, cold storage, dry ice production, rapid cooling, seawater desalination, air conditioning, intake air cooling, high purity ozone production, ethylene separation, low-temperature crushing, CO 2 solidifcation, CO 2 liquefaction, rubber cryogenic gridding and air liquefaction to N 2 , O 2 , and Ar production[12]. Conventional power generation technologies utilizing LNG cold energy * Corresponding author. Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman https://doi.org/10.1016/j.enconman.2020.113328 Received 22 June 2020; Received in revised form 10 August 2020; Accepted 11 August 2020