Enthalpy exchanger

An enthalpy exchanger for changing the enthalpy of a throughflow medium, i.e. a liquid, a gas or a two-phase medium, which enthalpy exchanger comprises:

• at least one air inlet;
• at least one enthalpy exchanger panel connecting to each air inlet and configured to guide medium such that during operation this medium exchanges enthalpy with airflows let through by the or each air inlet;
• an air throughflow space connecting to the at least one enthalpy exchanger panel;
• such that air can flow into the air throughflow space via the air inlets and the enthalpy exchanger panels;
• a fan which connects to the air throughflow space and has a central axis which is also the rotation axis of the rotor of the fan, which draws in and blows out air via the air inlets, the enthalpy exchanger panels and the air throughflow space;
• and
• electrical drive means added to the fan;
• wherein the ratio of the effective throughflow area of the fan and the total effective throughflow area of the relevant air inlets amounts to a maximum of about 0.3;
• added to the fan is a rotation-symmetrical airflow-guiding element which extends both upstream relative to the fan, in the air throughflow space, and downstream relative to the fan, on the outer side of the enthalpy exchanger;
• the airflow-guiding element has a streamlined shape in both its upstream zone and its downstream zone;
• the airflow-guiding element has in its downstream end zone a concave inner surface, smoothly transposing towards the fan into a locally at least approximately partly toroidal, convex remaining inner surface of the airflow- guiding element and having a continuously decreasing cross-section towards the fan;
• the airflow-guiding element has in its upstream end zone a convex inner surface having a continuously decreasing cross-section towards to the fan;
• the fan comprises a number of aerodynamically formed blades arranged in angularly equidistant manner on a coaxially placed hub and with outer end zones which are mutually connected by a concentric ring which fits with some clearance into a correspondingly formed annular recess in the airflow-guiding element, such that the inner surfaces of the ring and the airflow-guiding element connect substantially smoothly to each other without appreciably affecting the airflow through the fan.