بایگانی‌ها coil

انتخاب فاصله پره (Fin Pitch) در شرایط گردوغبار و آلودگی هوا در کویل های فین تیوب

21DecDecember 21, 2025

Fin Pitch Selection for Dusty and Polluted Air Conditions in Fin Tube Coils

Introduction In fin-tube coils used for heat exchange, selecting the fin pitch (spacing between fins) is critical for thermal performance and long-term reliability, especially in dusty or polluted atmospheres. An improper fin pitch can cause degraded heat transfer, excessive pressure drop, and more frequent maintenance. Factors affecting fin pitch selection • Type and concentration of contaminants: Environments with coarse particulate matter (industrial dust, sand) promote rapid accumulation on fins; therefore, wider fin spacing is recommended to reduce blockage. Environments with fine or sticky...

By پیمان داوریArticles, Technichal Points, Trainingcoil, Fin Pitch, Fin Tube

11DecDecember 11, 2025

Fluid flow direction inside the coil – upward and downward

Introduction In HVAC and refrigeration systems, the direction of fluid flow inside coils critically affects performance, heat transfer, and serviceability. Fin-tube water coils and refrigerant condensers require different flow orientations for distinct physical reasons. Fin-tube water coil — upward flow Problem addressed: Air trapped in tubes reduces heat transfer and creates zones of poor flow. Hydrodynamic reason: Air is much less dense than water and tends to accumulate at high points and corners of the coil. If water flows upward (bottom-to-top), entrained air bubbles...

By پیمان داوریArticles, Technichal Points, Trainingcoil, flow

09DecDecember 9, 2025

Bypass factor in a fin-and-tube coil

Bypass factor in the airflow passing over a fin-and-tube coil is an important parameter in the design and performance of heat-exchange systems. This factor represents the portion of the air stream that passes through the coil without effective contact with the heat-transfer surfaces (i.e., through the fins and tubes) and therefore does not participate in heat exchange, relative to the total airflow. Bypass is especially likely in fin-and-tube coils with improper fin arrangement, uneven fin spacing, or high air velocities,...

By پیمان داوریArticles, Technichal Points, TrainingBypass factor, coil

انتخاب بهترین سرعت هوا روی کویل‌ها: فن‌کویل خانگی و هواساز

04DecDecember 4, 2025

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...

By پیمان داوریArticles, Technichal Points, TrainingAir Velocity, coil

حذف یا کاهش فاصله هوایی بین فین آلومینیومی و تیوب مسی در کویل

28OctOctober 28, 2025

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...

By پیمان داوریArticles, Technichal Points, TrainingAluminum fins, coil, Copper Tube

تأثیر فاصله فین (FPI) در کویل فین-تیوب بر راندمان حرارتی و افت فشار

30SepSeptember 30, 2025

Effect of Fins Per Inch (FPI) in Fin-Tube Coils on Thermal Efficiency and Pressure Drop

Fins per inch (FPI) is a key design parameter in fin tube coils that directly affects heat transfer performance and airside pressure drop. Increasing FPI means more fins per unit length; this change brings both benefits and trade offs. Effect on Thermal Efficiency • Increased heat transfer area: Higher FPI increases the total fin surface area in contact with air, typically raising the overall heat transfer capacity of the coil. • Improved boundary layer disruption: More fins create more frequent air–metal interfaces, which...

By پیمان داوریArticles, Technichal Points, Trainingcoil, Fin Tube, Fins Per Inch, FPI, Pressure Drop, Thermal Efficiency

پروسه اکسپند لوله مسی به فین آلومینیمی در کویل فین لوله

21SepSeptember 21, 2025

Tube Expansion Process for Bonding Copper Tubes to Aluminum Fins in Fin–Tube Coils

<p> The tube expansion (expand) process used to bond copper tubes to aluminum fins in fin–tube coils is one of the critical manufacturing operations in heat exchanger production. The primary objective of this process is to create a stable mechanical and thermal contact between the tube and the fin such that thermal conductivity between the inner tube surface and fin surface is maximized, while ensuring sufficient mechanical strength and structural cyclic durability.

Process Steps and Methods

1. Alignment and...

By پیمان داوریArticles, Technichal Points, TrainingAluminum fins, coil, Copper Tubes, Expansion, Fin–Tube

28AugAugust 28, 2025

Introduction and Importance of Fin-and-Tube Coil Maintenance

Fin-and-tube coils (Fin and Tube Coils) are key components in HVAC systems, chillers, heat exchangers, and various industrial equipment. Maintaining the condition and performance of these heat-transfer assemblies requires adherence to specialized cleaning and maintenance procedures. Specialized Cleaning Procedures 1. Initial Inspection • Use high-resolution borescopes for internal visual inspection. • Assess contamination and corrosion level of aluminum fins. • Examine copper tubes for scale deposition and corrosion. 2. Preparation • Isolate power and gas supply. • Completely drain the working fluid from the system. • Install protective covers...

By پیمان داوریArticles, Technichal Points, Trainingcoil, Fin-and-Tube

تأثیر عیوب خم 180 درجه (استاندارد، چین‌خوردگی و دوپهــــن‌شدگی) در ناحیه یو بر عملکرد کویل فین-تیوب

18JanJanuary 18, 2025

Impact of 180° U-Bend Defects on the Performance of Fin-Tube Coils

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Overview

In fin-tube heat exchangers, the 180° U-bend region plays a critical role in fluid distribution, heat transfer, and pressure drop. When the bend is manufactured correctly—with proper curvature, constant internal diameter, and smooth internal surface—the flow field and thermal performance remain close to design values. However, two common manufacturing defects in the U-bend can severely degrade performance: local corrugation and local flattening. This document provides a technical assessment of all three conditions.

1....

By پیمان داوریArticles, Technichal Points, Trainingcoil, Fin Tube, U-Bend

روش‌های جلوگیری از خوردگی در کویل‌های فین-تیوب

18JanJanuary 18, 2025

Corrosion in Fin–Tube Coils and Methods for Preventing It

Fin–tube coils, which typically combine aluminum fins with copper tubes, are widely used in air-conditioning and HVAC systems. Corrosion in these components leads to reduced heat-transfer performance, efficiency loss, leakage, and shortened service life. The following sections present practical, preventive engineering methods for protecting these coils.

Material Selection and Proper Design

Corrosion-Resistant Alloys

Selecting aluminum and copper alloys with inherently high corrosion resistance—such as surface-treated aluminum alloys or copper alloys with controlled alloying elements—forms the foundational approach to durability...

By پیمان داوریArticles, Technichal Points, Trainingcoil, Corrosion, Fin Tube