how to set basement 1 in contam
chenke
chenke
the question the flow coefficient c in ELA-convert.xls(sheet "QREFtoELA") is different from ASHRAE FUNDAMENTALS 2021 CHAPTER 16 EQUATION(45)
Dols, William Stuart (Fed)
You can insert the basement levels below Lev1 with their corresponding heights (Distance to level above).
Once you’ve entered all the basement levels, you can set the bottom basement level to the negative of the sum of all the basement level heights.
- Stuart
--
To unsubscribe from this group, send email to
contam+un...@list.nist.gov
View this message at https://list.nist.gov/contam
Dols, William Stuart (Fed)
As indicated in the note associated with Ct_ELA (you can read the notes by hovering over the cell, e.g., cell F21), this is a value written to the CONTAM PRJ file.
This value is used by the CONTAM solver, ContamX, to calculate mass flow rate as presented in the column titled “Fela”.
You will see that the equation for “Fela” multiplies by the square root of the density (not diving, because it’s calculating mass flow instead of volumetric flow, F =
r Q).
In this way, ContamX, can use Ct_ELA (which is based on standard density of 1.2041 kg/m3 in CONTAM) with the current density for each time step during a simulation.
- Stuart
From: con...@list.nist.gov
con...@list.nist.gov On Behalf Of
chenke
Sent: Sunday, October 1, 2023 8:23 AM
To: con...@list.nist.gov
--
CK
This problem has been bothering me for one year.
CK
question2 : I can not find cell "Aplot " come from? and the equation"conv*SQRT(RHOplot)*Aplot*Ct_ela*$I11^n" come from the chapter of ahsrae handbook or screenplot ?
William Dols
The figure below shows the "flow elements" section of the PRJ and the coefficient is highlighted.
This could be corrected by modifying the formulas in this table (J22:L30) as follows (showing cell L22) "=IF(units="kg/s",L10,L10*RHOstd/RHOplot)".
CONTAM presents airflow results in units of mass flow based on standard density, hence the leading "s" in "sm3/s".
All calculations in CONTAM are performed in the base airflow units of "kg/s".
Dols, William Stuart (Fed)
Option 1 is incorrect. I’m not sure where 0.5 m2/m2 came from. You’re value for flow exponent (n) is 0.65 in this case.
Option 2 is close, but the Flow Exponents (n) do not match – you’ve entered 0.6 in the spreadsheet and 0.5 in ContamW.
This is the correct way to convert 0.5 m3/h-m2 to a flow coefficient for the model you’re using (except for the mismatched flow exponents).
The multiplier is correctly set to 168 to represent the area of a single wall.
The PRJ file that I reference previously, shows how to utilize different airflow elements to achieve the same result in CONTAM.
Some of the flow paths/element combinations demonstrate per surface area methods, i.e., having multipliers that represent wall surface area for a given airflow path.
Others having multipliers of 1 represent the entire leakage area for the “building.”
I am not familiar with GB21086.
Given, 0.5 m3/h-m2 at 10 Pa does not provide the flow exponent, n.
Assuming, it is 0.6 then the attached spreadsheet and PRJ show how to implement the various CONTAM flow element/path methods.
Note that the results of the simulation are all the same (zone pressure set to 10 Pa and zone temperature = 20 C).
Also note, the values of Ct_ELA on each page of the spreadsheet are all the same (indicating the data matches on each page).
------------
Previous message below:
hello Dols
The building 1 FLOOR (dimension：40000mm*40000mm*4200mm，length*width*height)，The curtain wall（one side） parameters（dimension ：40000mm*4200mm，width*height）:
A. The gas tightness level : air leakage 0.5m3/（h*m2），10Pa （from GB21086 , CLASS 4）
to set up parameters Option1：
Question1: About option1，the unit“m2/m2”of leakage area per unit area isn’t include “hour” which is included “0.5m3/（h*m2）”
to set up parameters Option2：
Question2: : About option2 , the power model Q=c(dP)^n which is suit to the glass curtain wall? The data-red wrapped is correct?
Question3, if above options are wrong, Could you please afford one correct file. Prj and file.xls ?
Thanks again！
CK
------------
- Stuart
From: chenke <chenk...@163.com>
Sent: Sunday, October 8, 2023 8:16 AM
To: Dols, William Stuart (Fed) <willia...@nist.gov>
Cc: CONTAM <con...@list.nist.gov>; chenk...@163.com
Subject: to set up parameters of the powerlaw model about curtain wall
hello Dols
The building 1 FLOOR (dimension：40000mm*40000mm*4200mm，length*width*height)，The curtain wall（one side） parameters（dimension ：40000mm*4200mm，width*height）:
A. The gas tightness level : air leakage 0.5m3/（h*m2），10Pa （from GB21086 , CLASS 4）
to set up parameters Option1：
Question1: About option1，the unit“m2/m2”of leakage area per unit area isn’t include “hour” which is included “0.5m3/（h*m2）”
to set up parameters Option2：
Question2: : About option2 , the power model Q=c(dP)^n which is suit to the glass curtain wall? The data-red wrapped is correct?
Question3, if above options are wrong, Could you please afford one correct file. Prj and file.xls ?
Thanks again！
CK
At 2023-10-03 21:38:06, "'William Dols' via CONTAM" <con...@list.nist.gov> wrote:
Question 1 & 2:
You can discover named ranges via the Name Manager in Excel.
Sorry, the names "Aplot" refer to the cells labeled "Achart".
This is the total wall area, i.e., the Multiplier used on some of the Flow Paths in the accompanying PRJ.
NOTE: All of the orange cells are for user input. You shouldn't have to change the values in any other cells. Use the Drop down on the Units to select the available values that are contained in ConvTable.
Question 3:
Refer to the ela-convert-v34.prj that accompanied the spreadsheet in the link you provided previously.
The figure below shows the "flow elements" section of the PRJ and the coefficient is highlighted.
Question 4:
The table of volumetric flows (Qfcn, Qqcn, Qela) is only correct if the Units selected are not "kg/s," i.e., there should be no conversion in this case.
This could be corrected by modifying the formulas in this table (J22:L30) as follows (showing cell L22) "=IF(units="kg/s",L10,L10*RHOstd/RHOplot)".Sorry for the confusion. This table really has nothing to do with CONTAM, but is meant to show the units of volumetric flow with which many folks are familiar.
CONTAM presents airflow results in units of mass flow based on standard density, hence the leading "s" in "sm3/s".
All calculations in CONTAM are performed in the base airflow units of "kg/s".See this thread for more info: https://groups.google.com/a/list.nist.gov/g/contam/c/ZkuoynMP7Bs/m/Kupo29hJAwAJ.
- Stuart
On Tuesday, October 3, 2023 at 3:26:36 AM UTC-4 chenk...@163.com wrote:
in fact, i had more troubles with your reply about ELA-convert.xls. Maybe , I am so poor in ahsrae handbook , hvac ,contaw software , excel, english an so on . i will appreciate if you can answer the follows questions:
question1: I can not find cell "convtable " come from , the units select"kg/s"，the conv "1.00" means “ set 1kg/s is primary unit for convert other units “，it is right ?
question2 : I can not find cell "Aplot " come from? and the equation"conv*SQRT(RHOplot)*Aplot*Ct_ela*$I11^n" come from the chapter of ahsrae handbook or screenplot ?
question3: As indicated in the note associated with Ct_ELA...., this is a value written to the CONTAM PRJ file. Could you show the positon of the value in contam or screenplot?
question4:
1)You will see that the equation for “Fela” multiplies by the square root of the density (not diving, because it’s calculating mass flow instead of volumetric flow, F = r Q).
2)In this way, ContamX, can use Ct_ELA (which is based on standard density of 1.2041 kg/m3 in CONTAM) with the current density for each time step during a simulation.
my understand is : F（mass flow ELA，0.5dP）=Qela( volumetric flow ELA )*RHOstd/RHOplot (0.5dP) , it is right ?
according to ELA-convert.xls 50Pa, F=0.7kg/s - 4Pa , F=0.04kg/s ，is right？
anyway，Thanks again！
在2023年10月2日星期一 UTC+8 22:03:14<Dols, William Stuart (Fed)> 写道：
As indicated in the note associated with Ct_ELA (you can read the notes by hovering over the cell, e.g., cell F21), this is a value written to the CONTAM PRJ file.
This value is used by the CONTAM solver, ContamX, to calculate mass flow rate as presented in the column titled “Fela”.
You will see that the equation for “Fela” multiplies by the square root of the density (not diving, because it’s calculating mass flow instead of volumetric flow, F = r Q).
In this way, ContamX, can use Ct_ELA (which is based on standard density of 1.2041 kg/m3 in CONTAM) with the current density for each time step during a simulation.
- Stuart
From: con...@list.nist.gov con...@list.nist.gov On Behalf Of chenke
Sent: Sunday, October 1, 2023 8:23 AM
To: con...@list.nist.govSubject: [contam] The question about the flow coefficient C
hi all
the question the flow coefficient c in ELA-convert.xls(sheet "QREFtoELA") is different from ASHRAE FUNDAMENTALS 2021 CHAPTER 16 EQUATION(45)
Which equation is right?
Another question is the abbr-word "ELA" means ?
--
To unsubscribe from this group, send email to contam+un...@list.nist.gov
View this message at https://list.nist.gov/contam
--
To unsubscribe from this group, send email to contam+un...@list.nist.gov
View this message at https://list.nist.gov/contam
---
To unsubscribe from this topic, visit https://groups.google.com/a/list.nist.gov/d/topic/contam/xhi7lP0_QS4/unsubscribe.
To unsubscribe from this group and all its topics, send an email to contam+un...@list.nist.gov.
William Dols
It looks as though you're converting specifications of leakage per length of door gap to leakage per envelope surface area.
Why do you need the flow coefficients themselves?
