Super Radiator Coil - Southwest Thermal Technology

When searching for a new heat exchanger, consider a custom-designed coil. The following tips will help you determine if a custom-designed unit will benefit your process.

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A coil using stainless steel components increases corrosion resistance, but it must be larger than a coil with aluminum or copper components to overcome the loss of heat transfer due to using a less efficient material.

Heating and cooling coils are offered as off-the-shelf standard units or can be designed to fit a specific application. At first glance, a coil does not look complicated, and attempting to enhance its performance may seem unnecessary and impractical. But, in some applications, custom-designed coils allow you to meet stringent process heating demands and minimize performance problems. Before specifying a new coil, consider the following tips to determine if a custom-designed unit can provide benefits to your process.

TIP 1: Keep Performance in Mind
A coil has no moving parts, and no performance-improving adjustments are required - and few can be made - once it is installed. It must be built with the required performance in mind. Therefore, performance optimization at the design stage is critical.

TIP 2: Consider a Variety of Materials
Assess the coil's operating environment, including both the external and internal environments so the proper materials and coatings can be selected. Other factors to consider include the temperature and pressure to which the tubes and fins will be subjected. Coils can be designed and built with the standard copper tube/aluminum fin construction or with other materials such as aluminum, copper, carbon steel, stainless steel, cupro/nickel, Hastelloy or titanium. In addition, various coatings can be applied to enhance corrosion resistance.

TIP 3: Recognize Material Affect On Performance
A material's thermal conductivity largely determines a coil's total heat transfer capability. Of the materials listed in the previous tip, copper tubes provide better heat transfer than steel tubes, and aluminum and copper fins provide better heat transfer than steel fins. Therefore, if the application requires steel components to withstand corrosive, high pressure or high temperature environments, the coil must be made larger than a coil using more heat-transfer-efficient components.

TIP 4: Consider Coil Shape
The basic shape (length, width and thickness relationship) is determined by the envelope into which the coil must fit. Usually, there are height, width or depth restrictions inherent to the installation that define the space available for the coil. Therefore, this also should be an initial consideration in the coil's design.

TIP 5: Optimize Heat Transfer
The purpose of a coil, or finned tube heat exchanger, as it sometimes is called, is to transfer heat between two mediums while isolating those mediums so they do not mix. To achieve heat transfer, there must be:

• A temperature difference between the two mediums.
  
• A pathway of material that allows conduction of heat so it can be conveyed from one location to another.
  
• A means of exposing the heat to the fluid medium.

If any of these items are lacking, heat transfer will not occur. This is reflected in the basic relationship from which all heat transfer equations are derived. Changing any one of these values affects the amount of heat that is transferred.

Q = U A DT

Where Q is the amount of heat transferred over time (BTU/hr)
U is the heat transfer coefficient (BTU/hr-ft2-degrees F)
A is the heat transfer area of the fin and tube material exposed to the mediums
DT is the temperature difference between the mediums (degrees F)

Copper tubes and fins provide better heat transfer than steel or aluminum tubes and fins.

TIP 6: Supply the Engineer With The Required Parameters
To ensure good design for your application, supply the engineer with the required parameters to design the optimum air cooling/heating coil for a specific application. Required design parameters include:

• The temperature (both dry and wet bulb) and pressure of the air entering the coil.
  
• The airflow rate available at the coil inlet side.
  
• Description of the tube-side medium, whether it is water, a defined water/glycol mixture or some other identifiable fluid.
  
• The entering tube-side fluid temperature and flow rate (gal/min).

In addition, the designer must be made aware of any contaminants in the airstream that may collect on the fin surface. This allows the designer to enter a fouling factor to account for the reduction in heat transfer resulting from the contaminated surface.

TIP 7: Realize Air and Gas Temperature And Velocity Affect Coil Design
The greater the temperature difference between the two mediums, the greater the heat transfer rate. This is the ? in the preceding heat transfer relationship. However, the actual air velocity also must be considered in the coil's design. A low velocity may result in inefficient heat transfer while too great a velocity (usually greater than 500 ft/min) will carry the condensed moisture with the airstream leaving the coil. High velocities create noise and high air friction, translating to higher fan energy usage. Also, forces developed by extremely high velocities could damage a coil if it is not properly designed to withstand them.

Therefore, the designer must consider the air velocity through the coil and strike the proper balance of air velocity, air friction and heat transfer efficiency. This is accomplished by coordinating the coil surface area with the fin configuration, fin density and rows-deep configuration. Optimum design will provide the best heat transfer performance with an acceptable velocity and air pressure drop.

TIP 8: Recognize That Tube-Side Fluid Temperature and Flow Velocity Affect Coil Performance
The fluids must contain the necessary potential to achieve the amount of heat transfer required. This potential comes from the temperature difference and flow rate. If the required potential is not available, either the temperature difference or the flow rate - or both - must be increased. In addition, the fluid's flow velocity through the tubes is critical to the coil's performance. Again, the design engineer is looking for the optimum combination of fluid velocity and fluid pressure drop. These factors are affected by the internal diameter of the tube, the number of tube circuits (flow passages) and the total lengths of the circuits.

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TIP 9: Provide Structural and Mounting Information
Good coil casing design requires knowledge of the type of installation and the shock, vibration and thermal loads to which the coil will be subjected as well as the type of environment to which it will be exposed. In addition to the overall size and weight of the coil, casing material, casing thickness and coil configuration will be selected according to these factors.

Stainless steel coils are highly sought-after because of their unique mechanical and physical characteristics. They are strong, lightweight, and corrosion-resistant. In addition, manufacturers can design stainless steel coils to meet custom design requirements. The market has different grades of stainless steel coils, each with special characteristics and applications.

Stainless steel coils are made by continuously hot-rolling stainless steel slabs. They are then wound tightly and left outside to cool down. This process ensures they finish with oxide- and impurity-free coatings.

Types of Stainless Steel Coils

Type 321

Type 321 steel coils are standard austenitic 18/8 chromium nickel alloy with titanium added. They are generally a great option for high-temperature situations. The titanium stabilizes the substance, increasing its resistance to intergranular corrosion. 321 is the preferred stainless-steel alloy choice when working in conditions up to °F (900°C).

Type 347

Type 347 stainless steel coils are the best to use for welding. Therefore, the preferred consumable for welding grade 321 is type 347. Even at cryogenic temperatures, the steel is good for forming and welding.

Type 304

Suppliers commonly carry type 304L stainless steel coils. Coils made of stainless steel 304 have remarkable corrosion resistance. Stainless steel 304 coils are durable and don’t rust quickly. Coils of stainless steel 304 are less expensive than other materials in terms of life cycle costs. These coils are popular because they are long-lasting. This product has a high scrap value and may also be recycled.

Industries That use Stainless Steel Coils

In the automotive industry, stainless steel coils are used for applications that require strong corrosion resistance and lightweight materials. Stainless steel coils are often used in structural applications for automobiles. Additionally, the use of stainless-steel coils in busses, subways, high-speed railroads, and other transportation systems is spreading.

Stainless steel coils are often used in the desalination and construction industries. However, stainless steel coils were first used in the building industry. Stainless steel coils are frequently used in decorative panels on buildings' exterior and interior walls. They are not only incredibly gorgeous but also durable. In addition, they are used as decorating elements in the construction and automotive industries.

Stainless Steel Coils’ Benefits

By itself, stainless steel provides many benefits as a building material. To begin with, stainless steel is very durable. Additionally, this material can handle the pressure of enormous weight. Furthermore, stainless steel is known to be corrosion-resistant. It is also resistant to cold and heat. This resistance helps materials housed by stainless steel pipes or other stainless steel items maintain their temperature and, as a result, save money on energy costs. Furthermore, stainless steel is easy to recycle; however, based on the assets listed above, and others, a user should not expect the need to recycle an item made of stainless steel for an extremely long time.

It’s precisely because of these benefits that stainless steel is formed into coils. As a coil form, this material is easy to shape into many products. Some items created from stainless steel coils include cutlery products, surgical instruments, filtration devices, various pipes and tubes, and various parts for air heaters, heat exchangers, and air coolers.

Conclusion

As hinted at, stainless steel coils have a wide range of mechanical capabilities and can be utilized to satisfy several requirements. Stainless steel is corrosion-resistant, lightweight yet incredibly strong, and needs little upkeep. As a coil form, stainless steel is primarily used in the industrial and construction sectors. However, they are also utilized in the mass production of nearly everything ranging from domestic items to industrial equipment. Stainless steel coils come in various varieties, each with a special function and set of characteristics. T300 series stainless steel 304 coils, for example, have a maximum of 0.08% carbon and a minimum of 18% chromium. It is categorized as chrome and austenitic nickel alloy. 304 stainless steel, sometimes known as “18/8,” is the most prevalent type of stainless steel used in pans and kitchenware.

Steel slabs are hot rolled in conjunction with a reheat furnace to create stainless steel coils, and a very high temperature is maintained throughout the manufacturing process. This process is followed because the recrystallization temperature must be reached to produce stainless steel coils.

Stainless steel coils can be employed in harsh environments due to their heat and fire resistance. In addition, outstanding corrosion resistance characterizes them. Its capacity to withstand corrosion is utilized in various applications, including mills, industrial equipment, medical devices, and many more.

Choosing the Proper Stainless Steel Coil Manufacturer

To make sure you have the most positive outcome when purchasing stainless steel coils from a stainless steel coil manufacturer, it is important to compare at least 4 to 5 manufacturers using our list of stainless steel coil companies. Each stainless steel coil manufacturer has a business profile page that highlights their areas of experience and capabilities and a contact form to directly communicate with the manufacturer for more information or request a quote. Review each stainless steel coil business website using our patented website previewer to get an idea of what each company specializes in, and then use our simple RFQ form to contact multiple stainless steel coil companies with the same quote.

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