6 replies to this topic

[elliot.433]

Hello All,

 

I am currently trying to find dew point of high temperature air (70-110 C) with low relative humidity (0 to 3%), 1 atm. 

 

I would greatly appreciate any pointers on correlations valid for this range or PSYCHROMETRIC charts that would have such a range. 

 

Regards,

Elliot

Edit: I found this chart and it holds the values I will use: BR0009-00_Psych_Chart_High_Temp.pdf (munters.com)

Edited by elliot.433, 13 July 2023 - 02:00 PM.

[latexman]

 High T Psychrometric Chart.png   585.22KB   1 downloads

 

By my eye:

 

70 C and 1-4% RH has a 26-28 C dew point.

 

110 C and 1-4% RH has a 40-47 C dew point.

[elliot.433]

latexman, on 13 Jul 2023 - 4:33 PM, said:

High T Psychrometric Chart.png

 

By my eye:

 

70 C and 1-4% RH has a 26-28 C dew point.

 

110 C and 1-4% RH has a 40-47 C dew point.

Hello, Thank you for the quick response. 

I am looking however for a chart that would include the range and would not need to visually interpolate the values or an equation valid for the range. 

Furthermore, it appears to me you have mentioned the wetbulb temperature rather then the dew point. Please correct me if mistaken. 

[latexman]

elliot.433, on 13 Jul 2023 - 6:01 PM, said:

I am looking however for a chart that would include the range and would not need to visually interpolate the values or an equation valid for the range. 

Furthermore, it appears to me you have mentioned the wetbulb temperature rather then the dew point. Please correct me if mistaken. 

 

I found that chart by Googling "high temperature psychometric chart".  Good luck finding what you want.

 

You are right.  Let me correct that:

 

70 C and 1-4% RH has a 26-28 C wet bulb temperature.  The dew points for 70 C are off the chart.

 

110 C and 1-4% RH has a 40-47 C wet bulb temperature and a 24-33 C dew point.

 

Will the numbers for 0% RH be meaningful to you?  That's pure air, and it'll depend on the properties of 21% O2/79% N2, which will be close to the boiling point of pure air, or -194 C.  Or, does it default to the dewpoint of the air dryer that provided your air, typically  this is -40 C.

[breizh]

HI,

Consider this resource to support your work. They also have a calculator on the web.

https://www.vaisala....dity-calculator

Breizh

[elliot.433]

latexman, on 13 Jul 2023 - 7:16 PM, said:

 

elliot.433, on 13 Jul 2023 - 6:01 PM, said:

I am looking however for a chart that would include the range and would not need to visually interpolate the values or an equation valid for the range. 

Furthermore, it appears to me you have mentioned the wetbulb temperature rather then the dew point. Please correct me if mistaken. 

 

I found that chart by Googling "high temperature psychometric chart".  Good luck finding what you want.

 

You are right.  Let me correct that:

 

70 C and 1-4% RH has a 26-28 C wet bulb temperature.  The dew points for 70 C are off the chart.

 

110 C and 1-4% RH has a 40-47 C wet bulb temperature and a 24-33 C dew point.

 

Will the numbers for 0% RH be meaningful to you?  That's pure air, and it'll depend on the properties of 21% O2/79% N2, which will be close to the boiling point of pure air, or -194 C.  Or, does it default to the dewpoint of the air dryer that provided your air, typically  this is -40 C.

 

The numbers at 0 will not be meaningful no. How ever I have edited the original post and have posted a chart with numbers that include the range I am looking for.

Thank you for the input!

[elliot.433]

breizh, on 13 Jul 2023 - 11:40 PM, said:

HI,

Consider this resource to support your work. They also have a calculator on the web.

https://www.vaisala....dity-calculator

Breizh

Great resource.

 

Thank you