How to Prevent Corrosion of the HVAC Coils

Preventing  HVAC coils from corroding can be frustrating.  It is difficult to protect against environmental pollutants such as salt-air, pesticides or cleaning agents, all of which are responsible for the failure of thousands of coils.

Preventing corrosion is largely depending on determining what type of corrosion is occurring.  The two mostt common types being --pitting and formicary.

Pitting 

Pitting corrosion is a result of chlorides or fluorides, which are found in numerous items such as snow melting

crystals, toilet cleaners, dishwasher detergents, fabric softeners, vinyl fabrics, carpeting and paint strippers. 

Pitting is commonly visible on the exterior of the copper tube and is caused when negatively-charged chloride/fluoride ions carried to the metal surface by condensate attack the oxide film metal uses to protect itself.  After pits have formed in the copper, they will progress through the thickness of the copper tube until a pinhole is formed causing the coil to leak refrigerant. 

Formicary 

Formicary corrosion is caused by organic acids like acetic and formic acids, which can be found in household products such as adhesives, silicone caulking, cleaning solvents and vinegar. Formic acid can be found in cosmetics, disinfectants and latex paints. While formicary corrosion is not usually visible, black or blue-gray deposits can sometimes appear on surface.  Formicary corrosion can form a sub-surface network of microscopic corroded tunnels within the tubing wall.  Eventually  one or more of these tunnels will progress to the surface of the copper and form a pinhole which results in coil leakage 

Protecting HVAC Equipment from Corrosion 

To help prevent damage to coils by corrosion, the HVAC industry depends on the four basic coating types.  What type of coating used  depends on the cause of the corrosion. 

	Developed	Application	Advantages	Disadvantages
Polyurethane	1940s	Fiberglass, rubber, sticky, soft upholstery foam.	Inexpensive, less viscous, flexible and thin.	Not as resilient or long-lasting as other coatings.
Epoxies	1920s	Coating floors and other surfaces.	Inexpensive, excellent chemical & heat resistance, best for heat transfer losses.	High viscosity, thicker coat, poor flexibility and adherence to characteristics.
Fluoropolymers (Teflon)	1938	Cookware & non-stick products	High resistance to acids, solvents and bases.	Expensive, limited lifetime & effectiveness.
Silanes		Coupling agents—bond two dissimilar materials such as paint and glass.	Flexible, glass like, resistant to corrosion and water draining capabilities, resistant against cracking, corrosion, hydropohobic and reduce airflow friction.  Best heat transfer properties & greater lifetime.	Expensive, difficult to apply properly,

Misdiagnosing the problem can result in unnecessary costs, which is why choosing the right coating for the problem is so vital.

Recent developments have been made in coatings, one of those being a product called Surfsil.   According to the creator, Surfsil "is a hybrid compound that uses nano-silicone technology to incorporate organic and inorganic properties.  This allows the coating to chemically adhere to the substrate via a covalent bond."

This product was tested following the ASAM B-117 Salt Spray (Fog) Standard, and there was no sign of corrosion after 10,008 hours. It's chemical bond prevents corrosion from growing under the coating, it is flexible & scratch resistant in addition to be resistant to chemicals found in HVAC/R equipment. 

How to Cut on HVAC Energy Waste

Lighting and HVAC systems are the primary culprits of high energy bills.   According to the U.S. Department and Energy's Efficiency and Renewable Energy (EERE) arm, lighting and conditioning indoor air makeup more than 50% of a building's total energy use.

For years, lighting has played a large role in cutting energy costs, with very little focus on HVAC. Now advancements in technology are making savings on HVAC systems more achievable.  Likewise, as the saving potential becomes more evident, facility decision makers such as managers and owners are starting to look for opportunities to reduce costs with current HVAC systems.

Three Ways to Cut on HVAC Energy Costs 

1. Fan Efficiency Ratings 

Fans are a large consumer of energy and account for 80% of the so-called parasitic load.   For this reason, the Air Movement Control Association International (AMCA), began developing an efficiency rating for fans.  By choosing a fan based on this rating system, you can reduce a significant amount on energy costs. 

2.Variable Refrigerant Flows 

VRF systems are common in Europe and Asia, but have only recently gained popularity in North America. Its ability to respond to fluctuations in space load conditions, enables energy savings during part-load system use. 

3. Energy Recovery 

Another option for saving on energy costs for facilities is the use of an airside or waterside direct exchange system.  For large facilities, energy recovery systems have the potential to cut energy conditioning energy use by half. 

HVAC Commissioning--Why You Need it

HVAC commissioning can enhance the lifespan
 of your mechanical equipment. 

What is HVAC Commissioning?  

HVAC commissioning is a thorough and comprehensive testing of a mechanical system's performance.  Many owner's are less than eager to spend more money, when they are already spending money to the contractor or engineer to fix the problem.   What most owner's don't realize is that commissioning can extend the life of equipment, while reducing operating costs and increasing the comfort of occupancy.

While the equipment should be properly installed in theory, there is not always sufficient evidence that the system is operating as optimally as it was design.  Varying operating conditions can certainly affect the equipment's ability to function properly.  It is usefully after the installation that the user discovers problems, and many times will attempt to fix the problem with patch and it makes it impossible to go back to the original intent of system.

Commissioning Process

Typically the commissioning contractor is the original contractor who installed the work, while the commissioning agent is the engineer who designed the project or was involved with the design process. The agent will stimulate a variety of operation conditions and work with the contractor to determine if the system is responding properly.

If discrepancies are noted, they will be diagnosed and resolved during the commissioning process.  Once, this is completed, the equipment is turned back over to the owner in perfect condition and in mechanical systems should be commissioned.

Any project with an automatic control of mechanical systems should be commissioned including:

• air conditioning unit 
• heating or cooling plant upgrades 
• project involving replacement or installation of automatic valves or dampers
• any installation or replacement fans, heating and ventilating units and duct heaters 

Looking for a competent engineering firm to commission your mechanical system?  RGD Consulting Engineers has 35 years of experience and can make sure your facility is operating effectively and efficiently.  

Thermostat Wars: HVAC vs. Home Security Industries

The HVAC industry is battling with homeowners, home security and home automation companies to determine who has the authority to install thermostats as a part of "smart home systems." 

The issues has taken on new heights with several HVAC industry organizations pushing for legislation to prevent home security and other non HVAC companies from replacing thermostats with products that communicate with security and home control systems. 

HVAC companies claim that HVAC systems use exclusive protocols and special communicating thermostats to control equipment that don't follow standard thermostat configurations, protocols or wiring. 

According to Dominick Guarino, the CEO of the National Comfort Institute, this approach to this issue has little substantiation, as many home security and home automation companies have their employees complete extensive education to be able to install this technology. However,  the issue that should be at the forefront of this battle, is who is responsible if the technology is incorrectly installed.  

Guarino recommends that instead of fighting this issue on a government level,  HVAC companies should fight this battle in the marketplace through education.  Let your customers know that having a third party install an intelligent thermostat could have negative consequences.

To learn more about this issue, visit the original article here.

How to Reduce your Energy Costs this Summer

Air-conditioning is often a welcomed relief from the unremitting summer heat, but the high costs associated with energy consumption can leave homeowners and facility managers unsatisfied. 

Currently, HVAC systems are responsible for around 40% of total building energy consumption, which is why it is no surprise that according to a recent report by Navigant Research, the revenue of energy efficient HVAC systems will increase from 17.2 million in 2013 to $33.2 billion in 2020.  

If an energy efficient HVAC system isn't in your budget this year, there are several budget friendly ways for keeping your energy consumption down this summer. 

1. Change your Filters 

Clean air filters are key to getting the best air flow from your HVAC system. Not changing your filters could mean more maintenance because it forces your system to work harder and less efficiently. 

2. Add Insulation 

Check to make sure your facility is properly insulated. According to the United States Department of Energy (USDOE), insulation not only can reduce your carbon imprint and save you money on your energy bill, but it can help maintain a consistent temperature throughout your facility. 

3.  Programmable Thermostats 

A programmable thermostat can help control your system even when you aren't around. By setting different temperatures for different times of the day,  you are better able to monitor your energy consumption and cut on your costs. 

4. Invest in

Energy Efficient Shades 

Keeping your windows covered all day and installing energy efficient shades can help reduce the load on your AC unit. 

5. Annual HVAC Systems Maintenance 

Like your car, your HVAC system needs a yearly checkup. This can help ensure that your system is running efficiently and prevent costly problems later on. 

Getting a cooling load calculation completed by a certified engineer can also determine the efficiency of your HVAC system and can make sure your system meets required building codes.  

Want to find out if your HVAC system is running efficiently?  RGD Consulting Engineers can perform an on-site inspection of your facility to determine the proper remediation to help you save money on your energy consumption. Inquire today!