Abstract: A method of assembling a heat exchanger including a method of determining the parameters Pl, Pf, .beta., and .THETA. in a heat exchanger wherein Pl is the width of a louver formed in a fin of the heat exchanger, Pf is the fin pitch, .beta. is the tilt angle of the fin and .THETA. is the tilt angle of the louver. The values of these parameters are determined so as to satisfy the expression ##EQU1## When the expression is satisfied, the efficiency of the heat exchanger is acceptable.

Abstract: A heat exchanger has a heat exchanger core comprising a single row of parallel tubes defining therein first series of passages for a first fluid and corrugated fins disposed between and thermally connected to each adjacent pair of tubes to cooperate therewith to define a second series of passages for a second fluid. Each tube is of a generally rectangular cross-section and arranged such that the longitudinal axis of the rectangular cross-section is parallel to the direction on the flow of the second fluid through the heat exchanger. The dimension of each fin as measured in the direction of the flow of the second fluid is within the range of from 12 to 23 mm, the pitch of the corrugated fins is within the range of from 1.5 to 3.3 mm and the dimension of the longitudinal axis of the rectangular cross-section of each tube is not greater than the dimension of each fin as measured in the direction of the flow of the second fluid.