The choice of installation diagram often comes from a compromise between different requirements, mainly concerning energy efficiency and ease of application. There are two different layouts possible for the recovery exchanger. Described in the following figures and where, for easy representation, the uses are summarised by a single sampling point. Nothing, however, should prevent you from thinking that this is its only use.
The aqueduct water exiting from the heat exchanger is mixed with hot water from the boiler to adjust the temperature of use. This diagram is suitable
for single use output heat recovery (typically, a shower), and in this case does not change the temperature of the “cold” home network.
One must distinguish between interventions on existing installations and new constructions. Obviously, in the second case it is more easily achieved from Diagram B with maximum energy recovery, as highlighted by the previous diagrams.