Abstract: A heat exchange process and apparatus are especially suited for use in heat recovery applications, especially in a run-around heat exchanger. The run-around heat recovery system has two liquid to gas heat exchangers, one for heat transfer with stale air being exhausted and one for heat transfer with fresh air being taken in. The two heat exchangers are linked with a common coupling liquid so that heat may be extracted from one of the air flows and added to the other. To improve the heat transfer process, a gas is injected into the liquid just before it enters one or both of the heat exchangers. The resultant mixed phase flow produces a much higher heat transfer coefficient in the heat exchangers, yielding a significant improvement in the system performance.