Counter flow
Counter flow and parallel flow refer to the direction of fluid movement in a heat exchanger, such as coils. In counter flow, the hot and cold fluids move in opposite directions, maximizing the temperature difference along the entire length of the exchanger. This results in efficient heat transfer. In contrast, parallel flow involves both fluids moving in the same direction. While it still allows heat transfer, the temperature difference decreases along the length of the exchanger, potentially leading to lower efficiency...
