A flow-plate is dividable in mid plane. The flow-plate includes two parts, each part includes a channel side and a utility side, and the two parts of the flow plate are counter parts and complementing each other. When the flow-plate is connected the two parts form a channel between the two counter parting channel sides. The channel includes curved obstacles, sidewalls and channel floors. The curved obstacles are lined up in parallel rows separated by sidewalls, the backside of the rows of curved obstacles have deep machined grooves making the obstacles hollow for heat transfer fluids on utility sides. A flow-plate section and a flow module are also disclosed.