The HVAC Coil Blog

Tube Bundles Explained

Posted By Tommy Thompson On 02/12/2018 at 01:50PM

Tube bundles are located inside shell and tube heat exchangers. The tube bundles are positioned within a cylindrical shell, where fluids at different starting temperatures (either be liquids or gases) pass through and over tubes. Heat is transferred from one fluid to the other through the tube walls, either from within the tube bundle (tube-side) to inside the shell wall (shell-side), or the other way around.

Bonnets and end channels regulate the flow of fluid in the tube-side circuit. Baffles inside the shell direct shell-side fluids across the tube bundle increasing velocity and turbulence, which increases the rate of heat transfer. Baffles must fit tightly within the shell to avoid performance loss from fluid bypass around the baffles. Baffles are usually attached to the tube bundle rather than the shell so the tube bundles can be easily removed for maintenance.

Having more tubes in the tube bundle increases heat transfer because there is a larger heat transfer surface. Surface enhancements can be added to increase the available surface or increase fluid turbulence, which also raises the heat transfer rate. Finned tubes may help when the shell-side fluid has a significantly lower heat transfer coefficient than the tube-side fluid. clients use tube bundles for compressor cooling, HVAC applications, power generation, industrial applications and refrigeration. The tube bundles are designed to work in industries such as aerospace, food & beverage, healthcare, marine, metals & mining, oil & gas, petrochemical processing and refining, pharmaceuticals and pulp & paper. Both U-Tube Bundles and Straight Tube Bundles (fixed tubesheet or floating tubesheet) can be fabricated to your specifications or cross-referenced with your current make and model for specs, providing you with tube bundles that are of the same or greater quality than the original.

Tube bundles can be ordered in a variety of materials, including Carbon Steel, Copper, Cupro-Nickel, Admiralty Brass, Stainless Steel, Duplex, Alloy 20, Inconel®, Incoloy® and Monel® 400. Call us at 1-855-Coil-Now for more information or to place an order.

Our stock coils database make ordering booster coils fast and easy

Posted By Tommy Thompson On 02/05/2018 at 10:43AM

Do you need booster coils or hot water coils in a hurry? We understand our customers need replacement coils fast, which is why we stock over 200,000 hot water coils and booster coils.

We specialize in replacement water coils of all shapes, sizes, and brands. Our searchable stock coils database includes part numbers and prices for hot water coils and booster coils. Our booster coils are designed for duct installations where heating needs to be “boosted” in certain areas.

Emergent Coils’ stock coils prices start at $150 to $1000, depending on the type and size of coil you need. The stock coils database allows you to run searches based on specifications, including: Tube Diameter, Casing Type, Rows, Fin Height, Fin Length, Fins Per Inch, and Connection Size. Performance data includes: Capacity, Air Flow Rate, Entering Air Temp, Leaving Air Temp, Air Pressure Drop, Entering Fluid Temperature, Leaving Fluid Temperature, and Fluid Pressure Drop.

The details contained in the stock coils database allow HVAC professionals to select and purchase new and replacement coils 24/7. Stock coils are typically shipped within three to five business days.

I wish we could stock every possible type and size of hot water coil and booster coil. If you don’t see what you need, give us a call. We offer 3, 5, and 10-day quick build options. Depending on the situation, a 1-day quick build may also be possible.

For HVAC professionals in need of custom coils, we provide custom hot water coils and booster coils to meet exact specifications. Blank drawings can be downloaded from the website to serve as measuring guides for custom coils.

Our coil experts are available to answer your questions and provide free quotes at 1-855-Coil-Now and

Why copper and aluminum are used in HVAC coils

Posted By Tommy Thompson On 01/29/2018 at 11:53AM

HVAC coils are often made with copper and aluminum, two metals that efficiently transfer heat. That’s because cost and effective heat transfer are often the key deciding factors in choosing materials for HVAC coils. There are pros and cons to both copper and aluminum, which I describe below.

Let’s start with some basics about where the heat transfer takes place in coils. In most HVAC coils, tubes are responsible for 30% of the heat transfer and fins are responsible for the other 70%. That’s because the surface of the fins is larger than the surface of the tubes.


Pros: Copper coils are stronger, easier to maintain, and more reliable than aluminum coils. Copper has a better heat transfer rate and is easier to repair in the field if the coil is damaged.

Cons: The cost of copper continues to rise, and copper coils require more material than aluminum coils.


Pros: Aluminum offers effective heat transfer at a lower cost than copper. Aluminum is more pliable than copper, so less aluminum is required.

Cons: Aluminum coils are difficult to repair and usually need to be replaced. Aluminum coils are also more difficult to clean and maintain. Aluminum fins can corrode, although this can be prevented with the application of a coating.

Given the pros and cons of copper and aluminum, we often sell HVAC coils that combine copper tubes with aluminum fins. Copper tubes offer the best heat transfer and aluminum fins offer good value. Chilled water coils, hot water coils, condenser coils and evaporator coils typically use copper tubes and aluminum fins. However steam coils and steam distribution coils often run at a higher PSI so we recommend stainless steel tubing depending on the pressure and application.

That said, there are times when steel or stainless steel is the best choice for tubes and fins. Steel and stainless steel are both good options when the steam pressure is too high for copper. Steel or stainless steel tubes should also be used when certain types of internal or external corrosion are an issue.

We are always here to help you with your commercial HVAC coil questions. To learn more about lowering your heating and cooling costs with new or replacement coils, contact us at 1-855-Coil-Now or today.

R-22 phaseout regulations HVAC technicians need to know for 2018

Posted By Tommy Thompson On 01/22/2018 at 03:14PM

The Clean Air Act requires the phaseout of R-22, a hydrochlorofluorocarbon (HCFC) compound that contains ozone-depleting chlorine. R-22 is also known as HCFC-22 and Freon. Manufacturing of HVAC systems using R-22 has already been phased out, and the production of R-22 itself will cease in 2020.

Section 608 of the Clean Air Act prohibits the knowing release of refrigerant during the maintenance, service, repair, or disposal of air-conditioning (AC) and refrigeration equipment. The EPA requires proper refrigerant management practices by technicians, owners and operators of refrigeration and AC systems, and others.

New regulations take effect for HVAC technicians on January 1, 2018, which I’ve summarized below:

Technician Certification Currently, technicians who maintain, service, repair, or dispose of equipment that could release ozone-depleting refrigerants into the atmosphere must be certified. Starting on January 1, 2018, this requirement will also apply to appliances containing most substitute refrigerants, including HFCs.

Technicians must: • Pass a certification exam offered by an approved technician certification program in order to maintain, service, repair, or dispose of appliances containing ODS or substitute refrigerants. • Keep a copy of their certificate at their place of business. • Maintain a copy of their certificate until three years after no longer operating as a technician.

Sales Restriction The sale of ozone-depleting substances (ODS) and substitute refrigerant is restricted to certified technicians.

New Recordkeeping for Appliances with 5 - 50 Pounds of Refrigerant Technicians who dispose of mid-sized appliances must keep records of: • The location, date, and type of refrigerant recovered for each disposed appliance; • The quantity and type of refrigerant recovered from appliances each month; and • The quantity and type of refrigerant transferred for reclamation or destruction, along with transfer information.

Maintenance, Servicing, Repair, and Disposal Technicians must evacuate ODS or substitute refrigerants before opening or disposing of appliances to the evacuation levels specified in the regulations using certified recovery and/or recycling equipment.

If you or your customers are in need of switching an Evaporator Coil or Condenser Coil to a different Refrigerant, you can email us at or call us at 855-264-5669.

Plan ahead for ordering HVAC coils in 2018

Posted By Tommy Thompson On 01/18/2018 at 09:39AM

Emergent Coils is your go-to source for new and replacement chilled water coils, hot water coils, steam coils, steam distribution coils, DX evaporator coils, [condenser coils]/applications/8-condenser-coil), booster coils, fan coils, tube bundles and heat exchangers. Now is the time to make plans for ordering HVAC coils in 2018.

• Take stock of your needs: Have you upgraded or added computer equipment, increased building occupancy, or made other changes that impact your heating and cooling needs?

• Inspect your coils: Have you noticed an increase in energy costs and a decrease in energy efficiency in your HVAC system? Are any coils corroded, leaking, or in danger of failing in the near future?

• Check your inventory: What HVAC coils do you already have in stock? What coils are missing? What coils do you routinely need to replace?

Once you understand the coils you are likely to need in 2018, we offer a host of resources on our website for advance planning.

• Sizing: Not sure how to measure or size your coil? We provide videos that show you how to size chilled water coils, hot water coils, steam coils, evaporator coils, condenser coils, and tube bundles.

• Blank drawings: Use our blank drawings to store measurements for water coils, steam coils, evaporator coils, condenser coils, tube bundles, and heat exchangers.

• Budgeting: Our searchable database of stock coils contains of over 200,000 hot water coils and booster coils, and includes part numbers and prices. For other types of coils, give us a call for pricing.

If you work for the government, our GSA contract - GS-07F-130DA - allows government agencies to easily purchase HVAC coils at approved pricing through the GSA Advantage! Website (link to ). Emergent Coils’ GSA contract runs through June 30, 2021.

Our coil specialists are available to answer your questions and make recommendations. They can help troubleshoot problems and uncover issues causing coils to fail, keeping you from having to replace the same coils over and over again.

Whatever your coil needs in 2018, please contact us at 1-855-Coil-Now or and let us make your holiday season a little easier!

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