Abstract: The invention concerns an assembly wherein a tank connects a return orifice to a delivery conduit via pumps. The tank is further connected to a surge tank. The tank is mounted in a steam proof chamber heat-insulated inside but having an air gap separation around the tank. Components are mounted sealed through the chamber. A filter subdivides the tank into a lower return chamber and a higher starting chamber.

Abstract: A used fluid passes through an exchange path, located in a fluid flow transfer, before returning to use at a required temperature. In the transfer path the exchange path is set between the evaporator and the condenser of a refrigerating circuit. The refrigerating circuit is actuated only when the temperature of the transfer fluid, consisting for example of ambient air, is unsuitable for properly modifying the used fluid temperature by means of the exchange path. The used fluid can be heated by simply reversing the direction of the flow in the transfer path. The invention is useful for rearranging exchange paths into a single transfer path, for example in a single bundle of tubes arranged in several tube layers of suitably connected tubes.