ENERGY RECOVERY VENTILATORS - GreenBuildingTalk - GreenBuildingTalk - Green Building Forums on Insulating Concrete Forms (ICF), Structural Insulated Panels (SIP), Radiant Heating, Geothermal Heat Pumps, Solar Power, Green Construction Projects - Green Building Technologies

Unanswered Active Topics

Forums Search Members

ENERGY RECOVERY VENTILATORS

Last Post 02 Jan 2008 06:20 PM by Dick Mills. 22 Replies.

Sort:

You are not authorized to post a reply.

Page 2 of 2

Author

Messages

Fred H

New Member

Posts:4

02 Jan 2008 10:43 AM
Mr. Mills, The highest CO2 concentrations I have been able to find ever recorded when there was not a volcano underneath or industrial CO2 production is around 1300ppm. This is in crowded conditions in basements without ventilation for extended periods of time. Where did the data on one human being able to create a CO2 level of 5000ppm come from? From what I have read, hundreds of people in a closet won't even get it that high. I just can't find any research that indicates human CO2 production being a problem. Do you know what research these recommendations are based on? Fred

GeorgiaTom User is Offline

Basic Member

Posts:159

02 Jan 2008 01:16 PM
Posted By Fred H on 01/01/2008 11:07 PM Mr. Mills - I would be interested to see any studies that have looked at elevated co2 problems in tight homes. At face value, I find the argument difficult to believe. Even if 10 people stayed in a home for 24 hours without opening a door or operating a spot ventilation fan, i am not sure this change in co2 level would present a danger. I would have to pull out my old physiology textbooks but I don't remember elevated co2 being a problem in the absence of an adequate O2 level. The air we breathe is only 21% O2 and our bodies don't really care what the other 79% is unless it is CO or some other gas that interferes with O2 binding to hemoglobin. Otherwise this "filler air" is just breathed in and out unchanged. I am greatly interested in any research you can refer me to. Fred I agree with Fred H , someones gotta open the door to get in .... leaving a 20 sq. ft. opening for a short period of time. I think 10 fellas watching the superbowl eating chips and bean dip would be a bigger worry with methane gas

Dick Mills User is Offline

Basic Member

Posts:217

02 Jan 2008 06:20 PM
You guys are right to a certain extent. I suspect that there are not many studies on the subject due to the fact that it is relatively easy to calculate the results. Of course, in the course of my calculations, I made two mistakes which skewed my number up to 5000 when it should have been 1450ppm - which is still not entierly insignificant. An average human will consume 1.57 pounds of O2 per day and produce 2.16 pounds of CO2 per day. My first mistake was that I compared the 1.57 pounds of O2 with the 313 pounds of O2 in my 20,000 cubic foot unventilated structure - that gave my erroneous number of 5000 ppm for one human over 24 hours. My next mistake was not including the quantity of carbon that is added in the form of CO2. The correct comparison would be 2.16 pounds of generated CO2 per 1490 pounds of Air. That results in 1450ppm for one human in that airtight 20,000 cubic foot structure - and obviously, the smaller the structure, the larger CO2 concentration. 1450 is considerably smaller than 5000, but not inconsequential. Dick Mills