The Importance of Heat Exchanger Coils

types of heat exchanger coils

While your air conditioning unit may seem like a complex machine, cooling your home is in essence, a very simple process. An HVAC system cools the air by replacing heated air with cool air through a heat exchanger coil. This coil transfers the heat between the fluids, such as water or intermediate fluid (Freon) present in your HVAC system.

While the exchanger coils in HVAC units all perform much the same function, there are many types and virtually an infinite size range of coils at work all over the world today.

Types of Heat Exchanger Coils

• Condenser Coils

• DX or Evaporator Coils

• Cold Water Coils

• Hot Water Coils

• Steam Coils

• Booster Coils

Common Coil Problems

For air conditioning units, direct contact heat exchangers are most commonly used to transfer heat from gas (air), using liquid refrigerants or chilled water in pipes. Cross flow is a type of heat exchanger coil that is most popular in air conditioners, especially since it utilizes a very efficient cooling system, causing the blowers to force the air over coils filled with the refrigerant or chilled water.

While HVAC units generally operate smoothly, there are several maintenance issues that must be considered. Condensation, freezing temperatures, and improper (or degraded) insulation are all problems that you must protect your HVAC unit from.

heat exchanger coil

Protecting Your Coils

As air is chilled, condensation is formed. This can cause rust and other problems to occur on your evaporators coils. To prevent rust in your heat exchanger coils, specialty coating can be applied to minimize damage from condensation. At American Coil, our AmeriCoat coil coating system is specifically designed to increase the durability, efficiency and lifespan of your coils.

 All of these problems can be solved with a specialty coil coating. AmeriCoat blocks corrosion, maximizes operating life, and minimizes cleaning and maintenance. Additionally, it does not affect heat transference. American Coil has developed one of the best coil coatings, specially formulated to protect HVAC coils against all the dangers inherent in an HVAC system, including extreme temperatures, microorganisms, rust, and corrosion.

Enduring Extreme Climates

Another concern with heat exchange coils or sheets is that many units are installed on the exterior of buildings or in spaces like attics that don’t have extensive insulation. As a result, the units are subjected to weather extremes, from hot summer days to freezing winter nights. While air conditioners rarely run in the winter, heating systems also rely on heat exchanger coils and these these coils must be protected.

Why HVAC Education Matters

air conditioning unit

Harsh winter temperatures can have detrimental effects on heating and cooling equipment. In order to prevent costly and devastating damages, consider an HVAC system with built-in backup to guarantee the efficiency and safe operation of your system.

The Experienced Choice

Accomplished HVAC industry professionals have the knowledge and experience to properly install and maintain heating systems. They can provide quality heat transfer products and new designs that can resist freezing temperatures and eliminate the possibility of damage.

Regardless of the size and scope of the project, an HVAC business that is trusted and respected will better understand your needs and how best to address them.

The Risk of Freezing Temperatures

Freezing temperatures can cause steam and water coils in HVAC systems to burst due to the expansion qualities of freezing water. The ways of deterring the effects of these freezing conditions often involve draining water from the system, the introduction of additives, or the use of freeze thermostats to recognize lowered temperatures. While beneficial, these techniques also have drawbacks, such as:

• Increased cost

• Reduction in system efficiency.

• Human error.

• Not having a backup if there is a system failure.

Knowledge of new technologies and techniques in the HVAC industry can help you to make an informed decision. The ideal system will prevent damage, reduce future expenses and can be recommended by a service professional.

At American Coil, we specialize in providing state-of-the art coils that can give you the confidence and security to weather any storm (or winter).

 

Cold Weather Steam Coil Preparation: A Money-Saving Solution

resistance heating coil

Forecasters are predicting that the 2016 winter season will reintroduce bitterly cold temperatures throughout the nation.

The presence of La Niña is expected to bring colder than normal conditions and an increase in heavy snowfall around the country. To keep your HVAC system fully operational throughout the coming seasons, it’s crucial to start your cold weather steam coil preparation now.

Steam’s Proven Track Record

For more than 100 years, steam has been a major source of heating in large commercial buildings and institutions.Steam heating has significant advantages over hot water heating and the steam coil’s ability to better resist freezing temperatures still keeps this old technology a very viable option for winter heating.

When most of the country suffered below freezing temperatures in 2013, steam coils fared much better in treacherous conditions than hot water coils. However, extreme conditions can still pose a threat to these sophisticated systems.

Cold Weather Risks

Although steam coils are designed to function through cold weather conditions, there are several factors that prohibit them from ideal performance:

• When there is more than one coil per steam trap, there is usually a difference in the outlet pressure of each coil due to airflow rate, dirt buildup, and coil construction. This pressure difference eventually causes condensate to flood the lowest pressure coil.

• If there are partially open or blocked louvers, condensation buildup in the coil’s tubes can cause uneven airflow.

• When there is too much pressure in a coil, the condensate cannot be raised to the return, resulting in a backed up coil. The elevated pressure can create a vacuum within the coil, preventing drainage and flooding the coil.

Any time that condensate is trapped within a coil, no matter the steam’s temperature, there is a danger of freezing. To ensure cold weather steam coil preparation, consult with the expert manufacturers at American Coil to assess the right coil solution for your system.

An Ounce of Prevention

At American Coil, we manufacture direct replacement heating coils for all of your steam coil needs. Working with our engineers ensures ideal performance on your system, provides you quick turnaround for coil emergencies, and guarantees you the most affordable options. We can advise on the current condition of your steam coils and present the best custom manufactured options.

Save money and time by preparing your steam coils for the cold weather. Maximize your coil efficiency and let American Coil ensure you a warm winter.

Protective Coil Coatings: What to Know, What to Ask?

If your business works with heating or cooling coils or your product contains a coil (or two), you are likely aware that the coil can be one of the most functionally important, and one of the most delicate, parts of a machine. You are also undoubtedly aware that when the coil portion of a device isn’t working, the device as a whole isn’t working, and that means down-time for your customer... not good.

There are two main causes of failure for heat transfer coils in appliances and HVAC equipment: mechanical damage and corrosion. Aside from incorporating physical protection for the coil, there is not much that can be done to prevent coil failures due to mechanical damage. Corrosion, on the other hand, is much more preventable.

Through the use of specially formulated coatings, corrosion can be drastically reduced or even eliminated. When it comes to coatings, the choices can seem endless, and it’s often very hard to differentiate one HVAC or AC coil coating product from another. When choosing a coil coating, there are many considerations and some very specific questions you will need answered. The information you need is often not contained in those glossy brochures being handed out at the trade shows. Although there are some great coating products (and processes) out there, there are also many that may not be up to the job. Don’t lead your company down the wrong path with an inferior coating choice for your application; ask the right questions, get the facts, and make a fully informed decision based on hard information, not just marketing claims.

Here are some basic questions you need answered about any coating before you commit:

• How is the coil coating applied?

Application method is key in how well the coil will be protected. The application of coatings generally fall within one of three distinct categories: Spray (Heresite ™, BlyGold ™ ect..), Immersion (AmeriCoat ™ Ozkem ™ ect...), and Electrically Applied (Electro-Fin ® & E-Coat).

Spray HVAC and AC coil coating is applied just as the name implies—sprayed onto external surfaces of the coil.

Spray Applied Pros:

• Ease of application

• Economically priced

Spray Applied Cons:

• Does not protect all surfaces of coil. Center of coil is left unprotected. Spray applied methods can’t penetrate into the center/core of the coil.

• Spray coating formulations are generally more brittle and prone to flaking off over time and/or when bumped during installation or servicing.

Immersion Applied Pros:

• Uniform coverage and protection of all coil surfaces, seen & unseen

• Innovative new formulations rival and can surpass even the electrically applied HVAC and AC coil coating durability.

• Certain formulations of immersion applied coatings have outperformed the more expensive electrically applied coatings in independent testing.

• Some formulations are FDA approved and safe for indirect contact with food.

• Accepted by several HVAC and foodservice OEM’s.

Immersion Applied Cons:

• Costs are generally a little more expensive than spray-applied coil coatings, but somewhat less than electrically applied.

• The process for coil preparation, application and process must be much more controlled than spray applied techniques, taking a bit more time and expertise to complete.

Electrically Applied Pros:

• The most uniform coverage, on both seen & unseen surfaces.

• Highly controlled environment for application, yielding predictable results.

• Better protection than spray-applied coatings and comparable with some of the best immersion applied HVAC and AC coil coatings.

 Widely accepted by OEMs.

Electrically Applied Cons:

• Only applied by one company, and is generally more expensive than spray or immersion applied HVAC or AC coil coatings.

• All coils must be shipped to the vendor’s location for coating application.

• Often takes 1-2 weeks for completion.

• Not FDA approved for contact with food.

• Some immersion applied coatings have greater long-term durability (as independently tested) than electrically applied.

• How is the Coating Cured? Proper curing is critical for the protection longevity of any coating.

unprotected center of coil

• Spray Applied: Some HVAC and AC coil coatings air-dry and some are heat cured. Heat curing is preferred.

• Immersion Applied: The best Immersion coatings are heat cured, some are air-dried. Heat curing is preferred.

• Electrically Applied: Heat Cured.

• How Long Will the Coating Protect the Coil? Review independent testing results.

• Each applier should have a technical data sheet for their coating offering, request it.

• The best coatings have undergone extensive independent testing for the following: Salt Spray, Acidified Salt Spray, Anti Bacteria & Mold, Moisture S02 Testing, Food Contact.

• The Salt Spray test is key; the best coatings can withstand 10,000 hours or more.

• How Does the Coating React to UV Light? Most HVAC and AC coil coatings don’t tolerate full UV exposure very well, some better than others.

• Some coatings can accept a top-coat of another product to help with UV, and some use a titanium binder formula (rather than the less UV tolerant copper). Some cannot be made to tolerate high doses of UV at all; ask your potential vendor about how their product deals with UV light exposure.

• How Does the HVAC and AC Coil Coating Effect Heat Transfer?

• The coating formula and application method will dictate heat transfer loss.

• The best coatings are specifically formulated for coil protection while also facilitating heat transfer, and can offer less than a 1% degradation. The ideal 1% or less degradation is available with select vendors in each of the three application method types. Check with your potential vendor. This information should be on their coating technical data sheet.

• Is the Coating Hydrophobic, Hydrophilic, or Neither?  This refers to how moisture reacts with the coating surfaces.

• Hydrophobic: Repels moisture, beading up, and running off vigorously. Best choice for most applications. Hydrophobic coils “sweat” carrying debris from surfaces, becomes almost self-cleaning. Also helps keep low airflow refrigeration coils from “ice-bridging” between the fin surfaces.

• Hydrophilic: Spreads moisture out evenly across coating surfaces (a sheeting effect). Useful in situations where coil is intended to stay wet or purposely sprayed with water to enhance heat transfer.

• Non-Engineered for Water Interaction: Does not address moisture/water interaction, not recommended.

water-interaction

What is the finished color of the coil coating?

• Most coils are visible in some way, and some colors can be more noticeable than others. Nobody wants attention drawn to the coils on their HVAC units or appliances. For aesthetic purposes, choose HVAC coil coating colors that blend the best with a coil’s surroundings. Color can also impact the latent heat absorption rate from sunlight; darker colors can attract heat, while lighter colors can help reflect it.

Request a sample : Most reputable coating appliers will readily offer samples, but sometimes you need to ask. Many times, the sample offered is simply a piece of fin material treated with their coating process. Those samples should only be regarded as a demonstrator of color. If you really want to judge the supplier’s finish product, you will want an actual coated coil sample (some coating appliers will even demonstrate their coating on one of your coils free of charge). A full coil sample will exhibit the coating facility’s ability (or inability) to apply their product evenly and with the desired finish, texture and hardness. There are many different surfaces and textures on a real coil, and the fin material is just one of them. You want a coating product and application process that looks good on all the coil’s surfaces and creates a look and function you can be proud to show to your customers. Many first time coating shoppers are surprised at what some coating appliers consider “functionally acceptable” as opposed to your higher expectations. Don’t settle… coated coils can work great and look great too, if you do your homework and choose wisely.

• You’ve decided on the best HVAC or AC coil coating for your application... now what?

When selecting a coating type and vendor, ask the important questions and get the answers you need to make an informed decision. Your potential vendor will know you are well versed and you’ll better position your company to favorably negotiate the details of the coating work contract. Once you decide on a coating product and process, you will surely want to know how to get the best price. The key to getting great pricing is knowing how your coating applier can save time and money on your job. Help facilitate those cost-saving situations for them and then ask that those savings be passed on to you… their new customer. This approach works best with small and medium sized appliers, as large scale coating firms may not have the flexibility or potential efficiencies that can be created for you to take advantage of.  So how can you help a coating company help you? Here are the ways you and coating appliers can save:

• Issue PO’s in batch quantities that most closely match the capacity of their oven. If your selected coating is heat cured, the oven is where your coating vendor will expend the greatest deal of energy (quite literally) to deliver your final product. Energy is expensive, and if you can help them get as many pieces as possible into each firing of their oven, then their cost per piece will go down, and so should yours.

• Offer a blanket PO for your coating work, up to 1 year out. Why? Because it can allow your vendor to plan their time and materials in the most efficient manner. Liquid coating raw material can be very expensive and some can take months to formulate and receive. How does a vendor know how much to keep in stock or have waiting for jobs? Blanket PO’s can help them forecast their demand and facilitate production planning. That means on-time deliveries and more controlled costs for everyone.

• Let your vendor keep some stock to coat during their slower times. Just like every business, coating facilities have busy weeks and slower weeks. A steadily full shop is the most efficient and profitable shop for any manufacturer, so help your vendor smooth out the peaks and valleys by leaving some stock at their facility to coat (at their discretion) in between their busy times. Set a completion date on your PO and allow them a few weeks or months to finish. It could mean big savings for everyone. Predictable workloads make efficient factories.

In a world where equipment operating environments are becoming increasingly caustic and the service life of machines is being pushed longer and longer, the need for coatings has never been greater. Coil coating products have grown in popularity exponentially over the last 15 years; and it is no wonder why almost all the biggest names in HVAC and refrigeration have started using coated coils in one or more of their product lines…... Because it works!