Pool boiling on vertical and horizontal heated plates with a dielectric fluid: Influence of vertical canal width

•Original testbench to study boiling on adjacent horizontal/vertical heated plates.•Confinement reduces wall superheat for low/medium heat flux on vertical plate.•Confinement lowers the CHF on vertical plate.•Boiling on vertical plate improves heat exchange for adjacent horizontal plate.•Boiling on horizontal plate has no effect on adjacent vertical plate.