Hairy black holes and holographic heat engine

By considering AdS charged black hole in the context of extended thermodynamic as the working substance we use it as a heat engine. We investigate the effect of hairy charge on the evolution of efficiency and Carnot efficiency along with electric charge. Because of interesting thermodynamic behavior of hairy black holes it would be natural to know their effects when we use black hole as a heat engine. We show that the hairy charge increases the efficiency, and so maximum temperature would be happened for bigger Maxwell charge when this hairy charge grows. For the fixed electric charges, the efficiency has a minimum value. In fact all critical points describe physical states except when the charge removed. If the electric charge takes a zero value then the hairy charge must be negative. We also seek behavior of the system for large charges which is provided a model with low-temperature thermodynamics. (C) 2020 The Author(s). Published by Elsevier B.V.