New York Hutterite Colony, February 2020

The case

In a Hutterite Colony in New York, Southern Alberta, black mould contamination was happening in a walk-in cooler.

The Problem

Aspergillus Niger (black mould) spores were reproducing at a high rate, which required a complete washdown and sterilization of
the cooler every week, to prevent individual health issues. Mould would form on the shelves and the necks of the preservative jars.

      Hutterite Colony Walk-In Cooler Coil                                                       Sanuvox Installation at Hutterite Colony

Sanuvox Customized Solution

The cooling unit was cleaned by a refrigeration technician and a Sanuvox IL40-G was installed to destroy the spores early July 2017.

Conclusion

There has not been any reoccurrence of mould in the cooler. Two months after install, the Colony bought two crates of pears, same harvest and variety. They stored the crates in two different walk-in coolers. The pears in the cooler without Sanuvox UV treatment started turning brown and rot within 5 days.

The pears in the cooler with Sanuvox UV showed no signs of degrade. The increase of shelf life of produce impressed the Colony and since then, they equipped the 2nd cooler, along with a root vegetable cold storage room. The Colony is very pleased with the Sanuvox equipment and appreciate having clean cooler with food that is not contaminated with black mould.

UAI Management LLC, October 2007

The case

UAI Management LLC purchased the SunTrust building on Lincoln Road in Miami Beach three years ago.

They wanted to make sure that the building’s air-handling system produced and circulated clean, fresh air, and operated at peak efficiency. But the assistant property manager and chief engineer quickly realized that there were problems with its filters and coil.

 

The Problem

The old Roll-O-Matic filter system with an oil base that was located on the roof of the building was very dirty, and the A/C coil was moldy as well. 

Although tenants didn’t complain because they had probably gotten used to poor IAQ, the air inside the SunTrust building never seemed quite right. There was a slight musty odor and the dust was everywhere. The coil and filters were cleaned twice a year, but it wouldn’t be long before mold would reappear.

IL Coil Cleaners mounted near / facing the coil.

Sanuvox Customized Solution

A series of high-performance filters would take away the airborne contaminants, but only UV would eliminate mold, bacteria and spores. Sanuvox Technologies recommended the installation of IL Coil Cleaners that shine on the coil 24/7, destroying bacteria, viruses, mold, chemicals, and their associated odors.

Sanuvox partnered with The Filtration Group, a filter manufacturer, and A-One Filters, which installs systems, to design a two-pronged strategy of treating the coil with the UV air purification technology and capturing the particulates with a series of energy-efficient filters. 

After sizing calculation, Sanuvox was able to determine the number of UV lamps that would be required for the system as well as the owner’s return on investment. This system would require five rows of four 40’’ UV IL CoilClean in line UV lamps, which were installed from top to bottom in front of the return side of the coil.

Conclusion

Tenants thanked the assistant property manager for being able to breathe cleaner air.

Because innovative technologies were used, the building earned not only LEED® certification but also won a prestigious national award for creating a cleaner, healthier indoor environment.

Formicary Corrosion & Biofilm Fouling of Cooling Coils

Formicary Corrosion and Biofilm Fouling of Cooling Coils

By Normand Brais, P.Eng., M.A.Sc., Ph.D.

INTRODUCTION

Air conditioning is responsible for substantial electricity consumption and peak demand in most of the United States. Over the past decade, energy conservation researchers have studied air conditioning more and more. Much of this research has focused on the impact of air flow, duct leakage, and refrigerant charge level on cooling performance.

One area, which has been neglected by researchers, is fouling of evaporator and formicary corrosion. Known commonly as ant’s nest corrosion, champagne leaks, or just simply as formicary, the issue presents as a hard to detect leak within the fin pack of an evaporator coil. This tiny leak or set of leaks results in loss of system refrigerant over time. While the incidence of formicary corrosion is low nationwide, it is more prevalent in warm, humid climates found in southern portions of the United States where slimy biofilms coat the coil fins.

 WHAT CAUSES IT

The tunneling action that leads to corrosion is caused by the presence of organic acids mixed with moisture on the copper tube within the fin pack. Two common acids known to cause formicary corrosion are formic and acetic acids. Certain manufacturing oils and lubricants can contain compounds that form these organic acids, but common household items can also breakdown to form formic and acetic acids. These can include building materials like formaldehyde adhesives, foam insulation, and laminates, as well as personal hygiene products like cosmetics, disinfectants, deodorizers, and cleaning solvents. To initiate corrosion, the presence of water is necessary. The corrosion rate is aggravated by the presence of mold biofilm that keeps the fins wet.

 HOW TO REDUCE IT

Every technician will tell you that every time they look at these coils, they are dirty with mold biofilm. A standard part of routine A/C maintenance and residential commissioning is to clean the evaporator coil with a wire brush and detergent or other cleaning chemistry, and to clean the outdoor coil of leaves and other debris. Over the last 20 years, the simple use of appropriate germicidal UV light can prevent this and keep the coil clean and free of any biofilm buildup.

The presence of mold biofilm on cooling coil acts like a water sponge that keeps the fins constantly wet and sticky, which capture and retain particulates and chemical contaminants, thus enhancing the formic acid corrosion rate. When the biofilm is eliminated with an efficient germicidal UV system, the coil is not permanently wet, does not trap and retains as much contaminants, and consequently its corrosion rate is greatly reduced.

                                                                                     Buildup of mold biofilm in lower right hand corner completely blocks air flow

Coils normally foul due to bioaerosols and other biologically active materials, which are ubiquitous in hot climates. This usually also lead to significant indoor air quality problems that can trigger respiratory allergic responses of building occupants.

                                                                        Fungal biofilm growth on a residential (Left) and commercial (Right) cooling coil

The biofilm that causes evaporator fouling and its accelerated corrosion also impacts on the cooling performance and energy efficiency. Large commercial heating and cooling coils have the same problems and are prone to the same type of fouling and consequential corrosion issues. Their lifespan can also be increased notably by using an appropriate UV germicidal system that prevents mold buildup in hot and humid climate.

The first step to take to reduce the formicary corrosion due is to prevent the formation of a biofilm of molds and fungi with an adequate germicidal UV system. Biofilm-free fins will be less susceptible to retain dusts and potentially corrosive compounds, as well as the moisture that activates the corrosion effect.

References

Siegel, Jeffrey, I. Walker & M. Sherman. 2002. “Dirty Air Conditioners: Energy Implications of Coil Fouling” Submitted to the 2002 ACEEE Summer Study on Energy Efficiency in Buildings.

Siegel, Jeffrey A. and W.W. Nazaroff. 2002. “Modeling Particle Deposition on HVAC Heat Exchangers.” Submitted to the Indoor Air 2002 conference.

Siegel, Jeffrey and I.S. Walker. 2001. “Deposition of Biological Aerosols on HVAC Heat Exchangers.”

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Extending Shelf-life & Delivering Exceptional Quality

Extending Shelf-life and Delivering Exceptional Quality

Mold and bacteria can severely impact the delicate payload on its way to storage facilities and retail stores. Ethylene off-gassing causes fruits and vegetables to prematurely ripen and age dramatically, shortening their shelf-life.

Sanuvox technologies offers an exceptional cost-effective mobile air treatment solution that easily incorporates into any truck or tailer designed to destroy airborne bio-chemical contaminants including bacteria, mold and ethylene off-gassing.

With its high efficiency patented air disinfection systems, Sanuvox offers the right solution when the objective is to destroy airborne contaminants, such as bacteria, viruses and mold that may affect the integrity of produce in transit. It also destroy ethylene, which causes produce to ripen faster.

THE EQUIPMENT

The 12V VP900 Interceptor is a small mobile air disinfection unit that can can be mounted in any location within the trailer or truck to sterilize airborne contamination and destroy ethylene gas. The UV system runs continuously bringing down contamination levels on an ongoing basis.

VP900 Interceptor:

OPERATING THE EQUIPMENT

The Interceptor recirculates the air, where:
1. The UV-C germicidal section of the UV lamp destroys airborne biological contaminants (viruses, mold, bacteria and spores).
2. The UV-V oxidizing section of the UV lamp reduces ethylene, slowing down the ripening process of vegetables and fruits.

SLOWING DOWN THE CONTAMINATION SPREAD WITH UV-C
Produce will degrade due to the rotting process. Rotting is caused by parasitic fungi and mold. Food deterioration begins with the breakdown of the cellular tissue by enzymatic action that allows the growth of microbes. Germicidal UV (UV-C) is extremely effective at preventing the reproduction of bio-contaminants. UV-C destroys airborne fungi, molds and their spores, limiting the contamination spread from one fruit to another. Meat, fish and chicken are especially vulnerable to airborne biocontamination. UV-C sterilizes the air, destroying contaminants as they circulate within the cold room.

RETARDING THE RIPENING PROCESS WITH UV-V
Photo-oxidation with UV-V can be used to reduce chemicals that trigger the ripening of fruits and vegetables. The life stages of a plant are influenced by plant hormones. An organic compound involved with ripening is ethylene, a gas created by plants from the amino acid, methionine. Ethylene increases the intracellular levels of certain enzymes in fruit and fresh-cut products, which include:

  • Amylase, which hydrolyzes starch to produce simple sugars.
  • Pectinase, which hydrolyzes pectin, a substance that keeps fruit hard.

UV-V oxidizes and thus neutralizes the ethylene molecules released by the ripening process, slowing down the spread of ripening to the surrounding produce.
This oxidation process breaks down ethylene into carbon dioxide and water vapor.
Ethylene C2H4 C2H4 + O* CO2 +H2O

WHERE TO INSTALL

The VP900 Interceptor can be installed in many places, like trucks transporting fruits and vegetables, cold storage rooms, groceries, fruit and vegetable retailers, or warehousing.

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