Impact of 180° U-Bend Defects on the Performance of Fin-Tube Coils
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04Dec
04Dec
Best Air Velocity Over Coils
Best Air Velocity Over Coils: Fan-Coils (Residential) and Air Handling Units (AHUs) 1. Introduction To achieve optimal heat transfer and minimize noise, the air velocity over coils must balance thermal performance with pressure drop and acoustic considerations. Below are recommended values and rationale, organized by application. 2. Residential Fan-Coils — Recommended Range • Air velocity: 300–500 feet per minute (fpm) over the coil face area provides the best balance. • Rationale: In this range the convective heat transfer coefficient (h) increases significantly compared to very...
02Dec
Cold-Room Condenser Unit: Applications and Key Purchasing Considerations
The efficiency of a refrigeration system in complexes and cold storage facilities is entirely dependent on selecting a cold-room condenser unit that is appropriate for the space. This article reviews the applications of cold-room condensers and highlights several key points to consider when purchasing this type of refrigeration equipment.
Applications of Cold-Room Condensers
Cold-room condenser units are most commonly used in the pharmaceutical, food, and agricultural industries, as well as in industrial freezers. Some food-storage warehouses are completely...
20Nov
Comparative Study Between Two Types of Fin Tube Coils
A detailed and categorized comparative study between two types of fin tube coils (aluminum fin - copper tube) and fin tube coil with aluminum tube, from the perspective of heat transfer, pressure resistance and corrosion resistance, is presented. Construction and materials Coil type A (aluminum fins + copper tubes): Fins are aluminum (common alloys) and tubes are copper (Cu). Fin-to-tube connection is commonly made by mechanically wrapping the fin around the tube, brazing/soldering, or using expanded joints. Coil type B (aluminum fins +...
18Nov
The engineering comparison of 5/8″ copper tubes with wall thicknesses 0.50 mm, 0.63 mm and 0.70 mm used in a water coil (fin-tube) with aluminum fins
Below is the engineering comparison of 5/8" copper tubes with wall thicknesses 0.50 mm, 0.63 mm and 0.70 mm used in a water coil (fin-tube) with aluminum fins. Internal heat transfer (controlled by conduction and convective heat-transfer coefficient) Internal convective heat-transfer coefficient (hi): for the same volumetric flow rate, thinner-wall tubes (0.50 mm) have a slightly larger internal radius and therefore slightly lower pressure drop and a similar or slightly higher hi compared with thicker tubes. Changes are usually small and mainly...
11Nov
Aluminum star-shaped fin
This study examines the effect of an aluminum star-shaped fin, placed along the axis of 5/8-inch copper tubes with a specific twist, on heat transfer in a shell-and-tube evaporator. The objective is to evaluate the enhancement of heat exchange and the reasons for using this geometric arrangement in refrigeration and HVAC applications. Fin design and configuration The star-shaped fin is formed from aluminum sheet into a multi-branch profile that fits inside a 5/8-inch copper tube and is twisted gently around the longitudinal...
04Nov
Comparison of mechanical pressure resistance in 5/8 inch tubes with wall thicknesses of 0.5, 0.63, and 1.0 mm
Introduction: This study briefly examines the mechanical and thermal behavior of copper tubes (5/8 in. size) with three different wall thicknesses (0.5 mm, 0.63 mm and 1.0 mm) in fin-tube coils. The goal is to determine approximate allowable pressure and temperature ranges and to explain performance differences resulting from wall-thickness variation. Material properties and assumptions: Material: commercial copper (e.g., C110) with ultimate tensile strength around 200–250 MPa and typical yield/working strength ~220 MPa, Young’s modulus ≈ 110 GPa. Outer tube diameter 5/8 in ≈...
30Oct
The Role of Aluminum Oxide in Fin Tube Coils Aluminum Fins and Copper Tubes
Effects on Heat Transfer and Corrosion Aluminum oxide (Al2O3), present as an oxide film on aluminum fins or as suspended/ deposited particles, has both positive and negative effects on the performance of fin tube coils (aluminum fins with copper tubes). Below is a concise review of these effects and the underlying mechanisms. Positive effects • Surface protection: A passive aluminum oxide film can act as a relatively stable protective layer that inhibits further corrosion of aluminum. This layer shows reasonable resistance to mildly...
28Oct
Elimination or Reduction of Air Gap between Aluminum Fins and Copper Tubes in Coils
Eliminating the air gap between aluminum fins and copper tubes in fin-and-tube heat exchangers (coils) is an important step in design and manufacturing that directly affects thermal performance, energy consumption, durability, and operating costs. This study examines why the issue matters, the effective heat-transfer mechanisms, technical and economic consequences, and practical implementation methods. Importance of Contact-Based Heat Transfer In fin-and-tube exchangers the primary objective is rapid and efficient heat transfer from the tube surface (carrying hot or cold fluid) to the air...
28Oct
Why Copper Tubes Are Used in Fin-and-Tube Coils
Introduction The choice of tube material in fin-and-tube coils strongly affects performance, durability, and life-cycle cost in HVAC, chillers, boilers, and heat exchangers. Copper (Cu) is one of the most common choices. Below are technical, organized reasons why copper tubes are preferred. 1. High Thermal Conductivity • Copper has very high thermal conductivity compared with many common metals (e.g., carbon steel). • High conductivity enables fast, efficient heat transfer between the fluid inside the tube and the external fins, improving overall coil heat-transfer effectiveness. •...
