Very good point. The purpose of using the assumption of well-mixed air is
due to the constrain of current heat balance thermal engine employed in
most simulation program. It is not easy to increase the "nodes" due to
extensive iteration triggered. However, what I can suggest is try to divide
single space into smaller ones along the stratified path. Although in each
smaller space, the air will still be well mixed, different set points can
be assigned in order to reflect the stratified effect. meanwhile, the
internal heat gain should be assigned into smaller spaces accurately. I can
foresee your hypothesis is correct that high roof R value will contribute
to minimizing heat loss through the roof.
Regards,
This paper from CU Boulder (
http://rp.ashrae.biz/page/ASHRAE-D-RP-1456-20110405.pdf) compares several
bulk airflow models (COMIS, CONTAM, EnergyPlus, ESP-r) with lab
experiments. They examine wind-driven, bouyancy-driven and combined-driven
flows. There's a long list of references at the end too.
Has anyone used COMIS, CONTAM and Energy Programs to evaluate infiltration, exfiltration, ventilation due to stack and wind effect in tall and super tall buildings? Can you get these values for any height (floor) of the building? I would also like to get information on research (published papers) on this topic.
I would like to have similar information on double wall commercial buildings and a list of such buildings. There are two in the US that I know of, one in Buffalo NY and other is Manulife Boston http://www.som.com/content.cfm/601_congress_street
Hey Arpan,
This paper from CU Boulder (http://rp.ashrae.biz/page/ASHRAE-D-RP-1456-20110405.pdf) compares several bulk airflow models (COMIS, CONTAM, EnergyPlus, ESP-r) with lab experiments. They examine wind-driven, bouyancy-driven and combined-driven flows. There's a long list of references at the end too.
Sam
First question ? Unconditioned & Un-occupied or Conditioned & Occupied
This is very important as conditioning mixes the air.
In unconditioned & un-occupied we have measured stratification. This has
resulted in the measurement of temperature at different heights which is
then averaged to obtain a room air temperature.
In EnergyPlus it's fairly straightforward to model room air stratification
Simply include one RoomAirModelType object per zone. This will give you the
ability to specify the zone stratification pattern desired. You can specify
a three node displacement ventilation pattern, an underfloor air
distribution temperature pattern, or a user defined gradient.
Very good point. The purpose of using the assumption of well-mixed air is
due to the constrain of current heat balance thermal engine employed in
most simulation program. It is not easy to increase the "nodes" due to
extensive iteration triggered. However, what I can suggest is try to divide
single space into smaller ones along the stratified path. Although in each
smaller space, the air will still be well mixed, different set points can
be assigned in order to reflect the stratified effect. meanwhile, the
internal heat gain should be assigned into smaller spaces accurately. I can
foresee your hypothesis is correct that high roof R value will contribute
to minimizing heat loss through the roof.
Regards,
Cheney
Hey Arpan,
This paper from CU Boulder (
http://rp.ashrae.biz/page/ASHRAE-D-RP-1456-20110405.pdf) compares several
bulk airflow models (COMIS, CONTAM, EnergyPlus, ESP-r) with lab
experiments. They examine wind-driven, bouyancy-driven and combined-driven
flows. There's a long list of references at the end too.
Sam
Has anyone used COMIS, CONTAM and Energy Programs to evaluate infiltration, exfiltration, ventilation due to stack and wind effect in tall and super tall buildings? Can you get these values for any height (floor) of the building? I would also like to get information on research (published papers) on this topic.
I would like to have similar information on double wall commercial buildings and a list of such buildings. There are two in the US that I know of, one in Buffalo NY and other is Manulife Boston http://www.som.com/content.cfm/601_congress_street
Hey Arpan,
This paper from CU Boulder (http://rp.ashrae.biz/page/ASHRAE-D-RP-1456-20110405.pdf) compares several bulk airflow models (COMIS, CONTAM, EnergyPlus, ESP-r) with lab experiments. They examine wind-driven, bouyancy-driven and combined-driven flows. There's a long list of references at the end too.
Sam
Dear Hayes,
First question ? Unconditioned & Un-occupied or Conditioned & Occupied
This is very important as conditioning mixes the air.
In unconditioned & un-occupied we have measured stratification. This has
resulted in the measurement of temperature at different heights which is
then averaged to obtain a room air temperature.
Dr Mark Dewsbury
Hayes,
In EnergyPlus it's fairly straightforward to model room air stratification
Simply include one RoomAirModelType object per zone. This will give you the
ability to specify the zone stratification pattern desired. You can specify
a three node displacement ventilation pattern, an underfloor air
distribution temperature pattern, or a user defined gradient.
Jason