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ASHRAE 62.Wonderful

When you think about ASHRAE 62.1 the first word to come to mind is probably not “Wonderful”. ASHRAE 62.1 is typically associated with design headaches, additional expense, and a general feeling of frustration. Most engineers I work with are constantly exploring ways to reduce the overall amount of outside air required for a space through either the Ventilation Rate Procedure (VRP) or the Indoor Air Quality (IAQ) method.

The conventional method to control Indoor Air Pollution is through “dilution” or the use of outside air via VRP. The IAQ procedure has been integral to ASHRAE 62.1 since 1981, but most consultants do not use it because of the time consuming process to identify the many variables and complete the mass balance calculations. While the use of outside air is an important aspect in improving indoor air quality, its limitations must be recognized:

  • Dilution is not an efficient means to control air pollution because increased air changes/hour reach a limit of effectiveness (see the picture below).
  • Most metropolitan areas in the USA have polluted outdoor air. Buildings are also sometimes located close to sources of localized pollution (highways, industrial plants, etc.)
  • The use of outdoor air is very costly except in the most temperate climates with low to moderate atmospheric humidity (i.e. not the Gulf Coast).


Ventilation Can Be Ineffective for VOC Control


We have all seen buildings designed with good air exchange rates but operated with their outside air intakes closed during winter and summer months to save on operating cost. Unfortunately this serves to accentuate, multiply, and cause indoor air pollution problems. Solutions such as high-efficiency filtration to control biological contamination are costly to operate, maintain and only display limited effectiveness. In addition, chemical media filters to control gas phase contamination are costly to operate and maintain and in many cases may not be able to be adapted to existing HVAC systems.

One of the manufacturers we represent, Bioclimatic Air Systems, has a proven design process and equipment that permits the reduction of ventilation air based on the Indoor Air Quality Procedure (IAQ) in ASHRAE Standard 62 via bi-polar ionization. The use of bi-polar ionization equipment also presents an economical solution to control several types of indoor air pollution including biological contaminants and many types of gaseous contaminants.

  • Reduction and control of airborne microorganisms (bacteria, virus and mold) through the process of electrolysis.
  • Reduction of many chemical gasses to a simpler and less objectionable form via separation and oxidation.
  • Neutralization of surface static charges. Therefore, normally buoyant particulate will have fewer tendencies to plate out on furnishings and building surfaces and will be transported back to the AHU to be filtered.

We’ll briefly explore bi-polar ionization below, but if you want more background about the process please click here.

Most matter in the universe is ionized. In the high vacuum of space, atoms and molecules are present in excited, energized states and possess electrical charges. By contrast, most matter on earth and in its atmosphere is not ionized. A source of sufficiently high energy is required to induce ionization and separation of charge. Energy can be supplied by natural or artificial sources, as derived from nuclear, thermal, electrical, or chemical processes. Ionization is the process, or result of a process, whereby an electrically neutral atom or molecule acquires either a positive or negative electrical charge. Ionization occurs when energy in excess of the ionization energy is absorbed by an atom yielding a free electron and a positive ion. A free electron can also combine with another atom to form a negative ion.

Engineered devices for intentional air ionization are more controllable than incidental sources. Bi-polar Ionization is a proven technology for the generation and control of air ionization. Bioclimatic’s equipment are “Non-thermal Plasma Generators”, and produce bi-polar ionization of more than 100,000 ions per cc. in an approximate ratio of 5 positive ions to 4 negative ions (this is the ratio of air ions normally found in clean, unpolluted air). Through careful control of the ionization process the formation of undesirable byproducts, such as Ozone, are minimized, and in most applications reduced to undetectable concentrations.

Bioclimatic has reduced the time consuming IAQ calculation process to a few key strokes with the use of independently validated IAQ software that contains all of the mass balance equations and includes the efficiency of Bioclimatic products. A few simple inputs for each zone include supply air, ventilation air, occupants, space volume, air distribution method and application type are all that is required to run the IAQ modeling software.


Bioclimatic Bi-Polar Ion Generator For a Fan Coil

Bioclimatic’s equipment, in conjunction with the calculations from its software, has helped thousands of facilities reduce their outside air requirements, saving both equipment and operational costs. For a detailed application guide on outside air treatment with bi-polar ionization please click here.

Through careful application of Bioclimatic’s equipment one engineering firm was able to reduce outside air for a school from 15 CFM to 5 CFm per person. The HVAC design utilizing Bioclimatic bi-polar ionization equipment eliminated the need for dedicated outside air equipment, saved on structural steel, reduced electrical service, and ensured that ventilation ductwork was reduced in size and capacity. You can read more about this case study by clicking here.

McNellage & Associates can help you with all aspects of outside air, from complex process dehumidification to outside air reduction. Every year we work with owners, architects, engineers, and contractors all over the Gulf Coast to design energy-saving HVAC equipment. We would love to work with you and your team! Click here to contact us and learn how to make your HVAC systems starting saving you thousands of dollars a year in energy costs.

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