In a heat exchanger, it is observed that $ΔT_1$ = $ΔT_2$, where $ΔT_1$ is the temperature difference between the two single phase fluid streams at one end and $ΔT_2$ is the temperature difference at the other end. This heat exchanger is
- a condenser
- an evaporator
- a counter flow heat exchanger
- a parallel flow heat exchanger