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Author - پیمان داوری

چه زمانی تعویض مبدل حرارتی (کویل فین-تیوب) به‌صرفه‌تر از تعمیر آن است؟
28Dec

When Is Replacing a Heat Exchanger (Fin Tube Coil) More Cost Effective than Repairing It

Fin tube heat exchangers play a key role in HVAC, heating systems, and industrial processes. Choosing between repair and replacement should be based on technical, economic, and operational analysis. The main criteria are outlined below. 1. Extent and type of failure • Superficial faults (worn fins, removable fouling, minor joint leaks) can usually be fixed by cleaning, repair, or replacing ancillary parts. • Widespread damage—such as multiple tube perforations, deep internal corrosion, structural frame failure, or severe fin deformation—indicates irreversible damage and often...

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آرایش لوله‌ها Inline vs Staggered در کویل‌های Fin & Tube
25Dec

Inline vs. Staggered Tube Arrangement in Fin-and-Tube Coils

Brief introduction: Fin–tube coils (aluminum fins and copper tubes) are commonly arranged in two tube layouts: inline (linear rows/columns) and staggered (triangular). Each layout affects airflow behavior, heat transfer coefficient, pressure drop, and manufacturing/installation costs. Inline layout Structural features: o Tubes are placed in regular rows and columns with uniform spacing; the pattern is rectangular/square rather than hexagonal.   Effects on heat transfer: Positives: Airflow is more uniform and less turbulent, giving a more predictable velocity distribution and simplifying convection modeling. Thinner, more stable boundary layers in some...

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انتخاب فاصله پره (Fin Pitch) در شرایط گردوغبار و آلودگی هوا در کویل های فین تیوب
21Dec

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...

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چه تکنیک‌هایی عمر مفید مبدل پوسته و لوله را به حداکثر می‌رساند؟
16Dec

What Techniques Maximize the Service Life of Shell-and-Tube Heat Exchangers?

Shell-and-tube heat exchangers, owing to their simple structure, enable effective heat transfer between different fluids and are therefore widely used in many industrial applications, including hydraulic-oil coolers. By implementing certain techniques, the operational lifespan of a shell-and-tube heat exchanger can be significantly extended, preventing unexpected production downtime and avoiding additional repair costs. The following sections examine key strategies for increasing the service life of shell-and-tube exchangers. Selecting a Shell-and-Tube Exchanger Based on Fluid Type One of the most impactful measures to enhance...

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Fluid flow direction inside the coil (upward and downward)
11Dec

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...

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بای‌پس فکتور یا ضریب کنارگذر در کویل
09Dec

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,...

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چگونه عمر مفید مبدل پوسته و لوله را افزایش دهیم
07Dec

How to Extend the Service Life of Shell-and-Tube Heat Exchangers

Shell-and-tube heat exchangers are predominantly used in facilities such as refineries and power plants. Consequently, the service life of these units has a direct impact on operational efficiency, auxiliary costs, and maintenance expenditures. Increasing the lifespan of a shell-and-tube exchanger requires adherence to several essential practices, the most important of which are outlined below. Regular and Proper Cleaning of the Exchanger Since shell-and-tube heat exchangers in refineries and power plants are typically exposed to chemical substances and deposit-forming fluids,...

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انتخاب بهترین سرعت هوا روی کویل‌ها: فن‌کویل خانگی و هواساز
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...

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Radiran Condensing Unit
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...

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مطالعه مقایسه‌ای دقیق و دسته‌بندی‌شده بین دو نوع کویل فین تیوب (فین آلومینیومی — تیوب مسی) و کویل فین تیوب با تیوب آلومینیومی، از منظر انتقال حرارت، تحمل فشار و مقاومت به خوردگی ارائه شده است.
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 +...

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