Samavirtalämmönvaihtimia

Samavirtalämmönvaihdin, or parallel flow heat exchanger in English, is a type of heat exchanger where the two fluids flow in the same direction. This counteracts the temperature difference between the fluids as they move through the exchanger, meaning the hot fluid's temperature decreases while the cold fluid's temperature increases. In a parallel flow design, the hot fluid enters at one end and flows to the other, while the cold fluid enters at the same end and also flows to the other end.

The main advantage of parallel flow is that it can achieve a higher outlet temperature for the colder fluid compared to a counterflow arrangement under certain conditions, especially when the flow rates or heat transfer coefficients are significantly different. However, the temperature difference between the two fluids is not as effectively utilized over the entire length of the exchanger as in counterflow designs. This often results in a lower overall thermal efficiency for a given surface area.

Parallel flow heat exchangers are employed in various applications where a higher final temperature for the secondary fluid is desired, or where simplicity in design and construction is a priority. Examples include some types of car radiators and certain industrial process heating or cooling systems. The choice between parallel flow and other configurations like counterflow or crossflow depends heavily on the specific application requirements, including desired temperature changes, available space, and economic considerations.