I am trying to lower the humidity of the air in a small chamber (about 0.5 cubic meters) so the dew point is below -50 Celsius. I need to be able to do this repeatedly. What would be the best way to do this?
2006-12-13 08:08:26 · 6 answers · asked by RyVu 2 in Science & Mathematics ➔ Engineering
I need very low humidities because I am working with refrigerants and cryogenic fluids and need to minimize condensation. I have considered using both a dessicant and a nitrogen purge. I seems that the nitrogen would be the easiest option for me. I tried using the nitrogen before, but only got the RH down to about 3%. I have realized that this was because my meter would measure any lower! Anyone know how low a dew point I can reasonably attain with compressed nitrogen?
2006-12-14 06:33:32 · update #1
As to the suggestions to "add heat..." adding heat reduces RH, but can not affect the dew point.
As noted, you will have a hard time getting air to a dew point that low. Would a different approach work? Could you use a nitrogen purge instead? This might be an easier way to get what you need, if what you need is "dryness" as opposed to "dry air."
2006-12-13 15:05:28 · answer #1 · answered by AnswerMan 4 · 1⤊ 0⤋
Add heat at a controlled rate if possible. Higher the temp, the less the RH if the volume of water in the chamber stays the same. I assume the chamber is sealed.
Another way is to add a evaporative refrigeration coil who's refrigerant is a lower temp then the ambient air (10 degrees is a goo TD). When you turn on the refrigeration in th eevaporator, moisture in the air that is flowing through the coil will attach itself to the coil (like in the old freezers that built up ice). Eventually the excess Ice will have to be removed via a defrost and drain line.
2006-12-13 11:50:08 · answer #2 · answered by dem_dogs 3 · 0⤊ 1⤋
cycle the air in your box over a "refrigeration" unit. it doesn't have to be too elaborate the moisture in the air will condense on the colder surface removing it from the air. I am no expert but this was the first thing that came to mind
2006-12-13 08:19:48 · answer #3 · answered by eric 3 · 0⤊ 0⤋
I believe a desiccant dryer will get you that low (that is really dry, man - what are doing, building the A-bomb?)
Most of them are rated at CFM @ -45°F dew point, but if you use them at less than half of that CFM, they might get you down there.
You might also try a lab equipment distributor.
I AM an expert at this....
2006-12-13 08:23:34 · answer #4 · answered by www.HaysEngineering.com 4 · 2⤊ 0⤋
You are trying to get the absolute humidity down to 0.03 g/m^3 -
I don't know that you will be able to accomplish this very easy if at all.
2006-12-13 09:31:40 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Can you fit a small resistance heater in there?
2006-12-13 08:14:17 · answer #6 · answered by Andres R 1 · 0⤊ 1⤋