Co curent flow fluids move in the same direction. In countercurrent flow, fluids move in opposite directions.

 Co curent flow fluids move in the same direction. In countercurrent flow, fluids move in opposite directions. Countercurrent flow is generally more efficient for heat transfer because it allows for a greater temperature difference between the fluids, according to Indian Institute of Technology Roorkee. 

Elaboration:

Cocurrent flow:

Both fluids enter the system at one end and exit at the other end, flowing in the same direction. 

Countercurrent flow:

Fluids enter at opposite ends and flow in opposite directions, creating a larger temperature difference for heat transfer. 

Efficiency:

Countercurrent flow is more efficient because the fluids are in contact with a greater temperature difference, leading to a more significant heat transfer rate. 

Applications:

Both cocurrent and countercurrent flow arrangements are used in various applications like heat exchangers, drying processes, and chemical reactions.