REVIEW PAPER Improving indoor thermal comfort by using phase change materials: A review Abuelnuor A. A. Abuelnuor 1 | Adil A. M. Omara 1 | Khalid M. Saqr 2 | Ibrahim H. I. Elhag 1 1 Mechanical Engineering Department, Faculty of Engineering, Sudan University of Science and Technology, Khartoum, Sudan 2 Mechanical Engineering Department, College of Engineering and Technology, Arab Academy for Science, Technology and Maritime Transport, Alexandria, Egypt Correspondence Abuelnuor A.A. Abuelnuor, Mechanical Engineering Department, Faculty of Engineering, Sudan University of Science and Technology, Khartoum, Sudan. Email: abuelnuor99@gmail.com Summary Phase change materials (PCMs) have great potentials to be used in modern building materials to stabilize indoor temperature fluctuations for improving thermal comfort. This paper presents a comprehensive review on the use of PCMs in buildings to improve thermal comfort without increasing energy con- sumption. Concise discussions of the experimental and computational works reported in literature are presented. A special focus of this review is devoted to discussing different analysis methods and models used to test, characterize, and measure the performance of PCMs in modern building applications under different conditions. This detailed review also highlights the special attention given to organic PCMs, such as paraffin, due to their favorable properties, such as low price, chemical stability, non‐corrosiveness, and high latent heat of fusion. The review shows the scarcity of literature reporting the use of eutectic PCMs in building applications, despite their high volumetric storage density. KEYWORDS indoor temperature, indoor thermal comfort, PCM, thermal energy storage 1 | INTRODUCTION The global energy demand is consistently increasing. 1 Such an increase has driven the renewable energy research sector to improve current alternatives to reduce energy consumption, especially in the building energy sector. 2 Solar energy is one of the main renewables with applications to the building energy sector. 3,4 Unlike other renewables, such as wind or wave energy, solar energy is intermittent along a short time scale and is only available during daytime. One way to improve such a disadvantage of solar energy usage is to use thermal energy storage (TES). 4,5 TES functions by absorbing and releasing thermal energy in the form of heat using a storage media. 3 TES systems stabilize power generation from solar energy throughout dedicated or combined energy cycles. Over the years, the use of TES with solar energy systems has been verified to reduce efficiently the exces- sive usage of fossil fuels in building energy systems. 6-10 TES plays a necessary role in a wide range of industrial and residential applications to improve the efficiency of Abbreviations: EPS, expanded polystyrene; GP, glass powder; HVAC, heating ventilation and air conditioning; LA–LWA, lauryl alcohol‐lightweight aggregate; LHS, latent heat storage; MPCM, microencapsulated phase change material; PCM, phase change materials; SHS, sensible heat storage; SSPCM, shape‐stabilized phase change material; TCM, thermochemical material; TES, thermal energy storage; TESC, thermal energy storage concrete; EAFD, electric‐arc furnace dust; TGA, thermo gravimetric analyzer; UHI, urban heat island; VIP, vacuum insulation panels; WPC, wood‐ plastic composite; xGnP, exfoliated graphite nanoplatelets Symbols: Q SENSIBLE , The sensible heat storage [kJ].; Q LATENT , The latent heat storage [kJ].; m, Mass of storage material [kg].; ΔT, Temperature change of storage material [K].; C p , Storage material specific heat capacity [kJ/kgK].; Δh, Specific melting enthalpy of storage material [kJ/kg].; Q, Amount of heat stored/released [kJ].; T es , the exterior surface temperature [°C]; T is , the interior surface temperature [°C]; T a , the internal air temperature [°C] Received: 3 August 2017 Revised: 22 December 2017 Accepted: 22 December 2017 DOI: 10.1002/er.4000 Int J Energy Res. 2018;1–20. Copyright © 2018 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/er 1