- #1

- 1

- 0

## Main Question or Discussion Point

Hey all,

As environmental physics isn't my forte, I have a problem that has been annoying me for about a month now at work and I am still getting no where with it... so any help with this head ache is much appreciated. The problem at hand is as follows.

A sealed metal housing is purged with 100% dry air until the dew point of the internal environment is -40 deg C. However, the seals on the unit are far from perfect and let in a known amount of water per day for a given environment, call it 1E-6 grams of water per day. The volume of the internal environment contained within the housing is known to be 0.003 m^3. The temperature and pressure of the environment is constant at 30 deg C and 101325 Pa.

At the end of one day, what is the relative humidity inside the metal housing?

I would prefer if any answers to this use formulas/theory as much as possible and refrain from using psychometric charts and steam tables. I am trying to repeat this over a large range of values on excel/matlab so repeat ability is key... unless someone knows of any psychometric chart resource already tabulated so that values can be searched for?

I am probably missing something terribly simple, but as mentioned any help will be much appreciated.

Looking forward to hearing any responses

Regards,

Euan Foster

As environmental physics isn't my forte, I have a problem that has been annoying me for about a month now at work and I am still getting no where with it... so any help with this head ache is much appreciated. The problem at hand is as follows.

A sealed metal housing is purged with 100% dry air until the dew point of the internal environment is -40 deg C. However, the seals on the unit are far from perfect and let in a known amount of water per day for a given environment, call it 1E-6 grams of water per day. The volume of the internal environment contained within the housing is known to be 0.003 m^3. The temperature and pressure of the environment is constant at 30 deg C and 101325 Pa.

At the end of one day, what is the relative humidity inside the metal housing?

I would prefer if any answers to this use formulas/theory as much as possible and refrain from using psychometric charts and steam tables. I am trying to repeat this over a large range of values on excel/matlab so repeat ability is key... unless someone knows of any psychometric chart resource already tabulated so that values can be searched for?

I am probably missing something terribly simple, but as mentioned any help will be much appreciated.

Looking forward to hearing any responses

Regards,

Euan Foster