Core unit of heat exchanger having electric heater

A core unit of a heat exchanger core having an air inlet side and an air outlet side, said core comprising:

• a plurality of parallelly disposed flat tubes which conduct heat carrier;
• a plurality of corrugated fins disposed in contact with said flat tubes;
• a support member having a pair of plates parallelly extending along said flat tubes, an opening end portion and a U-shaped closing end portion, said support member disposed between summits of corrugation of adjacent two of said corrugated fins, said U-shaped closing end portion is disposed at said air inlet side, each of said plates being bonded to one of said corrugated fins at summits of corrugation;
• and
• an electric heater disposed between said support plates and insulated from said support member.

A core unit of a heat exchanger including an inlet tank and an outlet tank for a heat carrier, said core unit comprising:

• a plurality of parallelly disposed flat tubes which conduct said heat carrier;
• a plurality of corrugated fins having summits disposed in contact with said plurality of flat tubes;
• and
• an electric heater disposed between two of said plurality of corrugations in parallel with said plurality of flat tubes, said electric heater having a positive temperature characteristic sharply changing resistance thereof at a set temperature, said electric heater being electrically insulated from said plurality of fins, wherein
• said electric heater with said set temperature heats portions of said fins adjacent to said flat tubes at a temperature equal to temperature of said heat carrier in said flat tubes if a temperature of said heat carrier is equal to or higher than 60° C. and temperature of air to be heated is equal to or lower than 0° C.

A core unit of a heat exchanger including an inlet tank and an outlet tank for a heat carrier, said core unit comprising:

• a plurality of parallelly disposed flat tubes which connect said inlet and outlet tanks to said heat carrier;
• a plurality of corrugated fins each of which is disposed between two of said flat tubes;
• an electric heater disposed at a portion of said heat exchanger core in parallel with said flat tubes, said electric heater having a positive temperature characteristic sharply changing resistance thereof at a set temperature, said electric heater being electrically insulated from said plurality of fins, wherein
• said fins have summits disposed between two of said flat tubes, said fins have a height between 3.9 mm and 5 mm, and
• said set temperature of said electric heater is between 85° C. and 120° C.

A method of manufacturing a core unit of a heat exchanger to be assembled with an inlet tank and an outlet tank, said core unit being composed of a plurality of parallelly disposed flat tubes, corrugated fins having summits, a pair of support plates and an electric heater, said method comprising steps of:

• stacking a portion of said flat tubes of said heat exchanger core and said corrugated fins alternately;
• stacking said pair of support plates in the same manner as said flat tubes between said summits of corrugation at a portion where said electric heater is to be disposed;
• soldering said flat tubes, said corrugated fins and said support plates into a unit;
• and
• inserting said electric heater between said two plates such that said electric heater is electrically insulated from said plurality of fins.

A core unit of a heat exchanger comprising:

• a plurality of cooling fins disposed in parallel with each other;
• a plurality of parallel tubes each of which is disposed in contact with first adjacent one of said cooling fins;
• a heater support member in contact with second adjacent one of said cooling fins in parallel with said plurality of tubes, said heater support member extending along said tubes;
• an electric heater held by said heater support member, said electric heater being electrically insulated from said plurality of fins;
• and
• a fastening member for applying fastening force to said core unit so that said electric heater can be tightly held in said support member, said fastening member having a pair of hook portions at opposite ends thereof and a band portion between said hook portions, said band portion having longitudinal draft opening to reduce draft resistance of air passing through said core unit.