Contents lists available at ScienceDirect Solar Energy journal homepage: www.elsevier.com/locate/solener Multi-objective optimization of energy performance of a building considering diferent confgurations and types of PCM Elin Markarian a , Farivar Fazelpour b, ⁎ a Department of Mechanical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran b Department of Energy Systems Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran ARTICLE INFO Keywords: Energy performance Economic assessment Genetic algorithm HAVC PCM ABSTRACT Phase change materials (PCM) can be outftted in building envelopes to not only provide thermal comfort for occupants but also trim heating, ventilation and air conditioning (HVAC) loads. However, the efcacy of PCMs depends highly on its thermo-physical properties and climatic condition. In this regard, a multi-objective op- timization technique is adopted to unearth the optimal type and location of PCM that can minimize heating and cooling loads considering fve cities of Iran namely Tehran, Tabriz, Bandar Abas, Shiraz and Yazd with dis- tinctive climates. Then, the optimal PCMs are environmentally and economically assessed. The study showed that the PCM with a melting temperature of 25 °C outperforms in terms of cooling load while the PCM with a melting temperature of 21 °C favors the heating performance. Moreover, the utilization of PCM results in electricity saving of 4.5–5.5% for all the climates. On average, the annual carbon footprint is reduced by 1297 kg, 1420 kg, 2040 kg, 1027 kg, and 1248 kg for Tehran, Tabriz, Bandar Abas, Shiraz, and Yazd, respec- tively. The payback period was found to be more than 70 years for all the cities considering current economic conditions. However, the energy subsidies are projected to fall in the near future that may make PCM integration economically feasible. 1. Introduction Building sector, contributing to one-third of greenhouse gas emis- sions, accounts for 30–40% of primary energy consumption (Wan Mohd Nazi et al., 2017; Omrany et al., 2016; D'Alessandro et al., 2018; Pop et al., 2018). An increase in building energy demand is also prog- nosticated due largely to growing population, enhancing indoor com- fort conditions and climate change (Souayfane et al., 2016). Moreover, according to Paris agreement (COP21), many countries including Iran are obliged to adopt low-carbon policies (Ascione, 2017; Wang et al., 2018; Fazelpour et al., 2018). Thus, energy efcient design of buildings and reduction of buildings’ energy consumption can assist the countries in meeting the terms of the agreement. Energy efciency of buildings depends heavily on building envelope and heating, ventilation and air conditioning (HVAC) systems. HVAC systems represent over 50% of buildings’ energy consumption (Marin et al., 2016; Verbeke and Audenaert, 2018). Moreover, a great share of energy is lost through the building envelope (Mao et al., 2019). Ap- plication of Thermal Energy Storage (TES) in building envelope is a practical solution to attenuate heating and cooling demand (de Gracia and Cabeza, 2015; Parameshwaran et al., 2012; Memon, 2014; Xie et al., 2018). The storage can be performed using three methods (Kenisarin and Mahkamov, 2016; Mehling and Cabeza, 2008): ther- mochemical reaction, sensible heat, and latent heat. Thermochemical energy storage in which thermochemical materials can undergo re- versible chemical or physical processes, is in early stages and requires further development. Sensible heat storage is the most widely applied method in buildings. The major drawback of this method is the need for massive materials (Izquierdo-Barrientos et al., 2012). Latent heat en- ergy storage has been gaining ground in recent years owing to high energy storage capacity within a narrow temperature range. Phase Change Materials (PCM) are capable of storing/releasing heat during a solid/liquid phase change process with an almost isothermal behavior (Kosny et al., 2013). Their storage capacity is 5–14 times per unit volume more than that of conventional materials such as masonry, water and rock (Devaux and Farid, 2017). The benefts of these mate- rials can be summarized as follows (Zhang et al., 2007; Álvarez et al., 2013; Ramakrishnan et al., 2015; Kuznik et al., 2011; Osterman et al., 2012; Mengjie et al., 2017; Lee et al., 2018): • Bridging the gap in peak and of-peak loads of electricity need • Reducing the electricity bill by shifting the load consumption to of- https://doi.org/10.1016/j.solener.2019.09.003 Received 20 May 2019; Received in revised form 14 July 2019; Accepted 2 September 2019 ⁎ Corresponding author. E-mail addresses: markarian.elin@gmail.com (E. Markarian), F_fazelpour@azad.ac.ir (F. Fazelpour). Solar Energy 191 (2019) 481–496 Available online 13 September 2019 0038-092X/ © 2019 International Solar Energy Society. Published by Elsevier Ltd. All rights reserved. T