Compact heat exchangers, which have a high heat transfer surface area per unit volume of the exchanger, are among the most important elements of many cryogenic components. Compact heat exchangers are heat exchangers with a surface area density (?) more than 700 m2/m3 on one or more sides of a two-stream or multi-stream heat exchanger. Compact heat exchangers of the plate fin variety are frequently employed in the chemical, automotive, cryogenic, and space industries. Since plate fin heat exchangers are primarily employed in nitrogen liquefiers, they must be extremely successful since, if their efficiency falls below 87%, no liquid nitrogen is produced. Therefore, it becomes vital to evaluate these heat exchangers' performance before putting them into use. The heat exchanger test rig is used in the laboratory to test the readily accessible plate fin heat exchanger, which has rectangular offset strip geometry. The experiment is carried out under balanced conditions, meaning that the mass flow rates on both sides of the fluid stream are equal and that varied mass flow rates are used throughout. Finding the heat exchanger's efficiency for various. The literature contains a number of correlations that can be used to estimate the heat transfer and flow friction characteristics of a plate fin heat exchanger. The various performance parameters—such as efficiency, heat transfer coefficient, and pressure drop—that can be determined experimentally are then compared to the values derived from the various correlations. The effectiveness of heat exchangers, particularly cryogenic heat exchangers, is decreased by longitudinal heat conduction through walls; therefore, the effectiveness and overall heat transfer coefficient are determined by taking the effect of longitudinal heat conduction into account using Kroeger's equation.