With the rapid development of modern infrastructure and the widespread adoption of centralized HVAC systems in large commercial buildings, the design and innovation of finned heat exchangers have become a primary focus in the industrial refrigeration and air conditioning sectors. As a universally applied heat transfer device in cooling and heating equipment, researching methods to significantly improve the thermal efficiency, optimize the design models, and enhance the overall performance of finned tube heat exchangers is of profound importance to the advancement of the entire HVAC industry. Within complex air conditioning units, the finned heat exchanger never operates in isolation; it serves as a critical structural link for thermal energy transfer and system integration, meaning that any micro-adjustment to its internal structure directly impacts the energy consumption and efficiency of the entire machinery.

In low-temperature refrigeration systems, the structural characteristics and geometric dimensions of the fins in an evaporator create substantial variances in heat transfer performance and aerodynamic resistance. Modern heat exchanger design principles heavily emphasize structural optimization by precisely adjusting and altering the fin spacing configuration. Engineering data demonstrates that by improving the fin spacing structure—specifically implementing variable spacing—while maintaining identical external dimensions such as total height, width, and overall tube length, the modified cooler achieves a heat transfer coefficient 9.8% higher than that of traditional equal-spacing designs. Crucially, while expanding the effective heat transfer area, this advanced design ensures that the cooler maintains a remarkably high heat transfer coefficient even when operating under severe frosting conditions, effectively achieving enhanced thermal performance through the dual mechanism of expanding surface area and elevating the transfer coefficient.

Beyond the optimization of external fin structures, advanced finned heat exchanger design principles also focus on augmenting the internal surface heat transfer area to intensify fluid turbulence within the tubes, all without increasing the overall physical footprint of the equipment. For instance, machining variable-pitch internal threads on the inner walls of the heat exchanger tubes drastically improves the internal thermodynamic dynamics of the working fluid. In practical industrial thermal management, when the heat transfer coefficient of the working fluid inside the tube is significantly higher than that of the air or gas outside the tube, the external convective heat transfer resistance becomes the primary bottleneck of the entire thermal process. Therefore, the strategic utilization of extended external surfaces combined with internal threading technologies plays an essential role in minimizing convective resistance, substantially reducing the physical volume of the finned heat exchanger, and maximizing the comprehensive thermal efficiency of the entire HVAC system.