Heat exchanger assembly with enhanced heat transfer characteristics

A heat exchanger assembly for use in an HVAC system, comprising:

• a shell-type casing;
• a plurality of tubes located inside the shell-type casing, each of the tubes having an outer surface and an irregular inner surface having sharp points;
• and
• a plurality of electrodes, each electrode having a smooth outer surface and being located inside one of the corresponding tubes to create a space between the outer surface of the electrode and the inner surface of the tube,
• wherein a first fluid is located in each space between the outer surfaces of the electrodes and the inner surfaces of the tubes, and a second fluid is located in a space between the tubes and the shell-type casing to flow across the outer surfaces of the tubes, the outer surfaces of the electrodes and the inner surfaces of the tubes being spaced apart from each other such that an electric field produced by a voltage being applied on the electrodes is intensified around the sharp points of the irregular inner surfaces to press the first fluid against the irregular inner surfaces in order to increase the rate of heat transfer between the first fluid and the second fluid.

A heat exchanger assembly for use in an HVAC system, comprising:

• a shell-type casing;
• a plurality of tubes located inside the shell-type casing, each of the tubes having an outer surface, an inner irregular surface and a first end;
• a tube head comprising a plate with holes for maintaining the first ends of the tubes;
• a plurality of electrodes, each electrode being located inside one of the corresponding tubes to create a space between the electrode and the inner surface of the tube and extending beyond the first end of the tube and the tube head;
• a refrigerant baffle and a cover plate, in conjunction with the tube head, defining a first region for a first fluid prior to the first fluid exiting from the heat exchanger assembly;
• an electrode plate mounted in the first region for imparting a voltage on the electrodes, the electrodes being electrically connected to each other;
• and
• a plurality of spacers for electrically insulating the electrodes from the shell-type casing, the electrode plate being mounted in the first region by the plurality of spacers,
• wherein the first fluid is located in each space between the electrodes and the inner surfaces of the tubes, and a second fluid is located in a space between the tubes and the shell-type casing to flow across the outer surfaces of the tubes, the voltage being applied on the electrodes in order to increase the rate of heat transfer between the first fluid and the second fluid.

A heat exchanger assembly comprising:

• a tube including a first end, a second end, an inner surface and an outer surface;
• and
• an electrode located inside and spaced from the inner surface of the tube, the electrode including an outer surface, the electrode having a voltage applied to produce an electric field,
• wherein a first fluid flows in the space between the outer surface of the electrode and the inner surface of the tube, and a second fluid flows along the outer surface of the tube, one of the inner surface of the tube and the outer surface of the electrode including surface irregularities having sharp points, the other of the inner surface of the tube and the outer surface of the electrode being smooth, the outer surface of the electrode and the inner surface of the tube being spaced apart from each other such that the electric field is intensified around the sharp points of the surface irregularities to pull the first fluid toward the surface irregularities to increase in the heat transfer rate between the first fluid and the second fluid.

A method of exchanging heat between a heat transfer fluid and a refrigerant in a shell and tube heat exchanger, comprising the steps of:

• providing an electrode having an outer surface inside a hollow tube having an inner surface, one of the inner surface of the hollow tube and the outer surface of the electrode being smooth;
• providing surface irregularities having sharp points on the other of the inner surface of the hollow tube and the outer surface of the electrode;
• flowing the refrigerant through the hollow tube between the outer surface of the electrode and the inner surface of the hollow tube, the refrigerant flowing along the inner surface of the hollow tube;
• flowing the heat transfer fluid around an outer surface of the hollow tube;
• applying a voltage to the electrode to create an electric field;
• and
• spacing the outer surface of the electrode and the inner surface of the tube from each other such that said electric field is intensified around the sharp points of the surface irregularities to press the refrigerant against the surface irregularities to increase the heat transfer rate between the refrigerant and the heat transfer fluid.