Desiccant Dehumidification w/ Tom Peterson

HVAC School - For Techs, By Techs

Bryan Orr

Training, Careers, Airconditioning, Self-improvement, Hvac, Business, Education, Refrigeration, Heating, Ac, Apprenticeship

4.8 • 985 Ratings

🗓️ 18 December 2017

⏱️ 44 minutes

🔗️ Recording | iTunes | RSS

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Summary

Learn about large-scale desiccant dehumidification from the expert, Tom Peterson. Tom works with CDI (Climate By Design International).

Dehumidification has several different methods and applications. Cooling is the most basic of those methods, but it has its limitations. For example, dehumidification by cooling may leave moisture on the coil and lead to freezing. Desiccant dehumidification can remove water from the air without the possibility of freezing the unit.

Desiccants are crystalline structures with pores, and they remove moisture via adsorption. Water has a pressure that pushes other water molecules into those pores. Partial pressures also help force the pressures from high to low. Moisture will only come out of the desiccant upon heating the air around it. Heat excites the water molecule that has been trapped in the desiccant pore, so that molecule breaks the bond between itself and the desiccant (desorption).

Commercial/industrial dehumidifiers make use of desiccants. Desiccants fit into rotors or wheels, and air passes through the desiccant rotor. The goal is to dehumidify and only dehumidify. So, no heat transfer occurs as air passes through those desiccant rotors. About 3/4 of the rotor works to adsorb moisture, and about 1/4 of the rotor works to desorb moisture.

We measure moisture in a unit of weight called grains per pound of dry air (simplified to "grains"). Grains refer to moisture rather than a humidity percentage, but grains and humidity are indeed linked. Even though we attempt to reduce grains per dry air, we cannot have negative grains of moisture; it is an impossibility.

Tom also discusses:

Sensible vs. latent heat
Grain depression
Dew point

Learn more about desiccants at the CDI website at cdihvac.com and their YouTube channel HERE.

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Transcript

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0:00.0	This episode of the HVAC School Podcast, like pretty much all of them is made possible because of
0:14.0	generous support from Testo, Rector Seal, and Carrier. You can see Testo, Rector Seal
0:20.1	and Carrier by going to the AHR conference.
0:23.6	This January, Testo is at Booth 7365,
0:27.3	and Rector Seal is at Booth 25, 45.
0:29.8	I will be at both of those booths,
0:31.4	both Tuesday and Wednesday at different times.
0:34.0	So you can hit me up.
0:35.0	In fact, if you want to email me, you can email me at Brian,
0:37.0	B.R.Ya and at HVacr School.
0:40.0	If you're there, and I will try to meet up with you at either the Testo Booth at 7365 or the
0:45.8	Director Seal Booth at 2545.
0:48.0	Meet Zoomlock, the 10 second flame-free refrigerant fitting from Parker.
0:52.5	Reduce labor costs by 60% with no braising, no flame, and no fire spotter.
0:57.5	Discover how Zoomlock can help you be more efficient and productive.
1:01.5	Visit Zoomlock.com for more information.
1:04.0	Sure he was an achr 40 under 40 in 2017, but it's no big deal.
1:16.0	He just has his room wall-papered with the announcement article.
1:20.0	Brian Orr.
1:21.0	Another little secret about me is that I am an Andy Griffith addict. I think I've probably watched every episode of Andy Griffith, the Andy Griffith show probably at least 10 times.
1:36.0	Now I have to I have to clarify here
1:39.0	the first five seasons of the good seasons
	...

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