This　study　aims　at　understanding　the　mechanism　of　heat　extraction　from　a　geothermal　reservoir　characterized　by　rough-walled　fracture　networks.　A　unified　pipe-network　method　(UPM)　which　simplifies　both　fractures　and　the　rock　matrix　as　pipes　is　developed　considering　the　local　thermal　non-equilibrium　(LTNE)　theory,　and　it　is　verified　against　an　analytical　solution.　Three-dimensional　simulations　of　macroscopic　fluid　flow　and　heat　transfer　in　a　fractured　geothermal　reservoir　are　conducted　to　take　account　of　fracture　roughness.　The　channeling　effect　and　the　heterogeneous　distribution　of　fluid　temperature　in　a　core-scale　model　with　a　rough-walled　fracture　surface　are　simulated.　An　equivalent　heat　transfer　coefficient　(EHTC)　is　obtained　from　numerical　experiments　with　respect　to　the　flow　rate,　mechanical　aperture　and　the　equivalent　hydraulic　aperture.　A　representative　element　volume　is　then　used　to　investigate　the　flow　and　heat　transfer　process　in　a　geothermal　reservoir　with　rough-walled　fracture　networks　by　applying　the　obtained　EHTC.　Results　demonstrate　that　it　is　essential　to　use　the　proposed　EHTC　since　the　constant　heat　transfer　coefficient　(HTC)　recommended　in　previous　studies　underestimates　the　final　outlet　fluid　temperature　in　cases　with　rough-walled　fractures.　(C)　2018　Elsevier　Ltd.　All　rights　reserved.