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  1. #1
    Join Date
    Jan 2010
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    10

    VOC problem, are ERV that efficient?

    VOC problem, are ERV that efficient? I work in Louisiana in a car paint store with VOCs. This forum make it clear to me that phi, and hydroxyl radicals won't cure it, but ventilation will. The problem is my AC guy is already bringing in roughly 600 cfm of fresh air intake, but not exhausting it. (I think this means the rooms have a positive air supply) I think it is also only going to bring fresh air only when the AC fan is on. Right now when the fan locked to the on position the paint fumes are improved but I think we can do a little better.

    Will an ERV with 1000 CFM's truly be more efficient? Will the savings in energy over 2 years pay off the cost of the ERV? In 5 years?

  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,588
    Why not determine the amount of fresh air you are getting into the space before you do more? Get a CO2 meter/data logger positioned centeraley in the store. During typical days, estimate the number occupants and compare the real CO2 levels. An estimate of the real cfm of fresh into the store can be made.
    I suggest operating the fan "on" during store hours. Also exhausting the paint area when mixing paint would improve the condition while controlling cost. Most buildings leak excessivey during windy weather but not much during calm warm weather. CO2 controlled ventilation may be of value to your customer. During windy weather, the CO2 levels will be very because of wind induced fresh air infiltration. ERVs that need to operate for extended periods of time to save by reducing mositure loads in your climate. You only need supplemental ventilation a couple hours a day, no pay back. After all the ventilation is in place, maintain <50%RH to maintain comfort. Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #3
    Join Date
    Jan 2010
    Posts
    10
    It is VOC that is a problem, not CO2, unless the gas meter determines CO2, O2, and VOCs. MY AC guy doesn't own a VOC meter.

  4. #4
    Join Date
    Mar 2003
    Posts
    7,326
    they can be up to 85 % efficient if applied correctly, depending on wheel style and composition. flat plate exchangers are less efficient.

  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
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    6,588
    Quote Originally Posted by Thurnau View Post
    It is VOC that is a problem, not CO2, unless the gas meter determines CO2, O2, and VOCs. MY AC guy doesn't own a VOC meter.
    The idea is to determine the fresh air change rate in the building. Nobody has a VOC meter good enough to match the nose. A CO2 meter cost less than $200. With a data logger $700. You considering speeding thousands without much information.
    The simplest is to exhaust the paint mixing area. Remove more air from the paint mixing area, while mixing paint. Exhausting VOCs through an ERV may not work well. Some transfer through the core.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  6. #6
    Join Date
    Jan 2010
    Posts
    10
    Thanks Teddy Bear and Flange,
    I am trying to exhaust the area. The area is 1200 square feet with a 4 ton unit. The AC company didn't want to take in anymore fresh air because it won't get cool enough in the summer, hot enough in the winter. I wanted to know if an ERV will let me exhaust voc, and bring in more fresh air without over burdening the system, while trying to conserve energy within reason and keeping my employees happy.

    Teddy Bear, how do VOC's transfer through the core? Is the core not air tight between fresh and stale air? Do the two streams of air intermix?

  7. #7
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,588
    Quote Originally Posted by Thurnau View Post
    Thanks Teddy Bear and Flange,
    I am trying to exhaust the area. The area is 1200 square feet with a 4 ton unit. The AC company didn't want to take in anymore fresh air because it won't get cool enough in the summer, hot enough in the winter. I wanted to know if an ERV will let me exhaust voc, and bring in more fresh air without over burdening the system, while trying to conserve energy within reason and keeping my employees happy.

    Teddy Bear, how do VOC's transfer through the core? Is the core not air tight between fresh and stale air? Do the two streams of air intermix?
    ERVs transfer vapors/VOCs from high concentation side to the low concentration. HRVs do not transfer these materials. Exhausting an isolated mixing area on demand is better than ventilating a 4 ton area. Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  8. #8
    Join Date
    Jan 2010
    Posts
    10
    This 4 ton unit is dedicated to 1200 square foot of area which should be exhausted all day. I am surprised that the ERV fresh and stale air actually co-mingle to transfer VOCs. Teddy Bear, you made things much more confusing, but I think you saved me quite a bit of money too.

    Thanks

  9. #9
    Join Date
    Jan 2005
    Location
    Area 51
    Posts
    984
    http://www.sanuvox.com/

    Try talking to this company about your problem
    "Paddle faster, I hear banjo music"

  10. #10
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,588
    Quote Originally Posted by Thurnau View Post
    This 4 ton unit is dedicated to 1200 square foot of area which should be exhausted all day. I am surprised that the ERV fresh and stale air actually co-mingle to transfer VOCs. Teddy Bear, you made things much more confusing, but I think you saved me quite a bit of money too.

    Thanks
    The air does not co-mingle. The air exhaust/fresh air stream are separated by a thin sheet of porous material. This material passes heat, moisture and condensible voc gases from the high concentrations to low concentrations. About half of gases pass through.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

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