Re: [EnergyPlus_Support] CO2 concentration temperature dependant ?

["Jean Marais jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx>]

Like Richard showed "note CO2 generation rate per unit of activity level". Which makes sense. The body trying to regulate its temperature may use slightly more energy, but I think it's neglagible (otherwise it could be counter productive).Do the added windows increase your infiltration rates?

Extra Info:  moisture from occupants is calculated by e+ based on the difference between total and sensible heat, where total heat is from the activity level and sensible gain is:
=(6,461927+0,946892*$BM7+0,0000255737*$BM7^2+7,139322*$AS7-0,0627909*$AS7*$BM7+0,0000589172*$AS7*$BM7^2-0,19855*$AS7^2+0,000940018*$AS7^2*$BM7-0,00000149532*$AS7^2*$BM7^2)*BL7

where BL is the number of persons

and BM is W/Person based on the Activity Level.

2017-03-06 15:59 GMT+01:00 Richard Raustad RRaustad@xxxxxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:

 

From what I can see in the model, the CO2 generation should not vary based on zone temperature. The activity level is set by a user defined schedule and the total heat gain is based on the number of people.

ActivityLevel_WperPerson = GetCurrentScheduleValue( ActivityLevel );
TotalPeopleGain = NumberOccupants * ActivityLevel_WperPerson;

Then the CO2 gain rate is calculated based on the rate factor you defined.

CO2GainRate = TotalPeopleGain * CO2RateFactor;

If you can't find an answer you should send your input file to the HelpDesk at http://energyplus.helpserve.com/ or use the UnmetHours site to ask a question at https://unmethours.com/questions/


People,
  N6 , \field Carbon Dioxide Generation Rate
       \note CO2 generation rate per unit of activity level.
       \type real
       \units m3/s-W
       \default 3.82E-8
       \minimum 0.0
       \maximum 3.82E-7
       \note The default value is obtained from ASHRAE Std 62.1 at 0.0084 cfm/met/person over
       \note the general adult population.

On 3/6/2017 8:32 AM, 'Geert Bellens' geert.bellens@bestbuildingconcept.be [EnergyPlus_Support] wrote:

Richard,

 

Itâ??s just a testmodel, so the OA is fixed (30 m³/h/person).

 

 

Geert

 

 

Van: EnergyPlus_Support@yahoogroups.com [mailto:EnergyPlus_Support@yahoogroups.com]
Verzonden: maandag 6 maart 2017 13:59
Aan: EnergyPlus_Support@yahoogroups.com
Onderwerp: Re: [EnergyPlus_Support] CO2 concentration temperature dependant ?

 

 

I would suspect with window heat gain, the zone load increases and supply air flow rate also increases thereby increasing the amount of OA entering the zone which lowers zone CO2.
Look at the supply/OA flow rates for each case.

On 3/6/2017 3:16 AM, geert.bellens@bestbuildingconcept.be [EnergyPlus_Support] wrote:

Hello,

I'm testing the CO2 concentration function. I put the outdoor CO2 at 400ppm and created several rooms with different volumes, with one person in each room.

Each room gets 30 m³/h outdoor air, continously. There are no windows who can open, there is no infiltration.

 

When I have no windows in the building and the temperature is stable at 20°C, I have maximum CO2 concentrations between 916 ppm and 983 ppm, which looks normal to me.

 

Adding 90% windows (which raises the temperatures) gives CO2 concentrations between 758 and 911 ppm.... very strange. 

 

Is there a relation between the temperature and the CO2 concentration? I don't think so.

 

I see that the human CO2 generation rate is defined as 0,0000000382 m³/s/W . 

With higher temperatures, the sensible heating rate of persons drops, but does this mean that the CO2 generation rate drops at the same rate? (I can't see this dependancy in the result viewer however)

 

 

Geert

 

 

 

-- 

Richard Raustad

Florida Solar Energy Center

1679 Clearlake Road

Cocoa, FL 32922

Ph: (321)638-1454

http://www.fsec.ucf.edu/en/

 

Program Director

Electric Vehicle Transportation Center

http://evtc.fsec.ucf.edu/

-- 
Richard Raustad
Florida Solar Energy Center
1679 Clearlake Road
Cocoa, FL 32922
Ph: (321)638-1454
http://www.fsec.ucf.edu/en/

Program Director
Electric Vehicle Transportation Center
http://evtc.fsec.ucf.edu/

__._,_.___

---

Posted by: Jean Marais <jeannieboef@xxxxxxxxx>

---

EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

The EnergyPlus web site is found at:
http://www.energyplus.net/

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.

Visit Your Group

• New Members 8

• Privacy • Unsubscribe • Terms of Use

__,_._,___