Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman Energetic and exergetic performance comparison of different polygeneration arrangements utilizing geothermal energy in cascade E. Pastor-Martinez a, ⁎ , C. Rubio-Maya a , V.M. Ambriz-Díaz a , J.M. Belman-Flores b , J.J. Pacheco-Ibarra a a Universidad Michoacana de San Nicolás de Hidalgo, Faculty of Mechanical Engineering, Morelia, Michoacán, Mexico b University of Guanajuato, Mechanical Engineering Department, Carretera Salamanca – Valle de Santiago km 3.5 + 1.8 km, Comunidad de Palo Blanco, Salamanca, Guanajuato, Mexico ARTICLE INFO Keywords: Energetic analysis Exergetic analysis Polygeneration systems Geothermal cascade systems ABSTRACT In this paper, the energy and exergy performance of several polygeneration arrangements driven by low and medium temperature geothermal resource is investigated. The aim is to assess and compare different coupling schemes, identifying suitable thermally driven technologies for each type of arrangement. The polygeneration system is intended to produce power, cooling and heat for direct uses by considering variations of series and parallel coupling schemes along with different alternatives of ORC and absorption cooling machines. The study was conducted considering a temperature range of low-to-medium geothermal resource from 80 °C to 150 °C. Mathematical models are developed based on first and second law of thermodynamics and solved by means of an equation solver. The results show a threshold temperature that makes a shift between feasible polygeneration arrangements and the type of thermally driven technologies adopted, resulting in two different polygeneration arrangements with highest energetic and exergetic performance. The first arrangement correspond to a tem- perature range that lies between 80 °C and 110 °C, and the second one between 110 °C and 150 °C. The poly- generation arrangement with highest exergetic performance for the first range of temperatures was the hybrid parallel-series cascade arrangement (HPS2) having exergy efficiencies between 42.82% and 50.11%, while the one corresponding to the second temperature range was the series cascade arrangement (SC1) presenting exergy efficiencies from 51.44% to 52.9%. This effect is a consequence of the available temperature of the geothermal resource and the intrinsic energy performance of the different technologies considered. In regard to thermally driven technologies, arrangements where ORC and TDC subsystems are placed at the first thermal level, are the ones with the highest energetic and exergetic performance. Arrangements that have those components at the last level, present lowest performances. 1. Introduction Nowadays, the consumption of fossil fuels continues satisfying the world ́ s growing demand for energy, which means environmental im- pacts and an accelerated depletion of fossil fuel reserves. In recent years, attention has been focused on finding more efficient forms of energy use as well as the use of renewable energies to mitigate en- vironmental problems and other energy issues. On the one hand, among renewable energies, geothermal energy is reported as an abundant and non-intermittent source of thermal energy in different world regions. The geothermal energy potential is 1814 EJ/year, which 403.2 EJ/year are classified as high temperature resources (more than 150 °C) and 1411.2 EJ/year correspond to low-to-medium temperature (between 20 °C and 150 °C) [1–3]. Geothermal resources of high temperature are being effectively utilized for electricity production and the installed capacity is still growing [4]. However, in spite of the great potential of the low-to-medium temperature geothermal resources, they are not being utilized massively because of technology limitations for using low temperature heat for electricity production, low energy conversion ef- ficiency as well as high investment and production costs [5,6]. Direct or non-electric use of geothermal energy, that is the immediate use of the energy rather than converting it to electricity, is the most common form for using geothermal resources of low temperature. Direct uses include, drying, space heating, cooling, industrial processes, greenhouses, crop drying, balneology and other processes. On the other hand, several methods aimed to increase the efficient use of energy resources, reduce production costs and to mitigate en- vironmental impacts, have been proposed. These methods include, https://doi.org/10.1016/j.enconman.2018.04.096 Received 23 January 2018; Received in revised form 11 April 2018; Accepted 25 April 2018 ⁎ Corresponding author at: Group of Energy Efficiency and Renewable Energy (GREEN-ER), Mexico. E-mail address: pastorme@hotmail.com (E. Pastor-Martinez). Energy Conversion and Management 168 (2018) 252–269 0196-8904/ © 2018 Elsevier Ltd. All rights reserved. T