Rinnakkaisvirtalämmönvaihtimessa

Rinnakkaisvirtalämmönvaihdin, known in English as a parallel flow heat exchanger, is a type of heat exchanger where the two fluids flow in the same direction. In this configuration, the hot fluid enters at one end and flows alongside the cold fluid, which enters at the same end and also flows in the same direction. This design is characterized by a temperature difference that gradually decreases along the length of the exchanger. While it offers simplicity in construction, the parallel flow arrangement is generally less efficient in heat transfer compared to counter-flow designs. This is because the driving force for heat transfer, the temperature difference between the fluids, is not maintained as consistently throughout the exchanger. The maximum possible temperature of the colder fluid is theoretically limited by the inlet temperature of the hotter fluid. Parallel flow heat exchangers are often chosen for applications where a large surface area is available, or where the cost of a more complex counter-flow design is prohibitive, and a slightly lower thermal efficiency is acceptable. They can be found in various industrial and domestic applications where heat transfer is required, though their use is often balanced against the performance benefits of other heat exchanger configurations.