Talk:Dehumidifier

Comment
Does there exist, an Ultrasonic dehumidifier? The humidifier topic speaks of the ultrasonic, and that topic is well written. Mikey

Comment
Explained very nicely. Great!!

Anyone have info on the lifetime of dessicants? Do they last forever? Sales pages don't seem to indicate a lifetime. I bought a cheap ($10 on sale) dessicant dehumidifier that I weigh to determine its effectiveness, and it seems to be less effective over time, though my recordkeeping was sloppy, so I'm not sure. It holds about 4 oz. If you add info, please delete this comment. I'm wondering if [I should use/they just use] salt. Elvey 16:35, 20 February 2006 (UTC)

Although I don't have a specific answer to your question, I do have a story related to dessicants. I spilled some white wine in the trunk/hatchback of my car so I rinsed and towel dried it. Since I was afraid of mold growing I also bought a dessicant. This one was designed to hang in a closet to keep the clothing nice. It had a nice smell so even after the trunk area was clean and dry I left it there, and forgot all about it. About two months later on a very hot day I returned to my car to find that the bag of dessicant had turned into a leaky gelatinous mess. Yuck. So I suppose there is a limit to what they can absorb and clearly you want to dispose of it before it has reached its capacity.

Desiccant Wheel
"Desiccant Wheel" -- I've seen this mentioned several times in the context of dehumidification for evaporative cooling, but never explained. Would someone who knows what this is add it to the article? Thanks! krc 03:33, 2 December 2007 (UTC) —Preceding unsigned comment added by Rumpuscat (talk • contribs)

"Very high humidity levels are also unpleasant for human beings, cause unsightly condensation and can make it hard to dry laundry."

Sentence
I don't know what this means with the second clause, except that the typer messed up some grammar. Deleting it until someone knows better.

Unreferenced long section removed
I have removed the following section, beacuse it is a bit long, and not referenced. I'd be happy with it being included again if it had references for the processes.

The component that holds the desiccant material can have several forms. In one design, a cylinder sometimes called a "tower", holds the desiccant material. The process air is drawn through the cylinder for a period of time adding moisture to the desiccant then regeneration air is drawn through the cylinder which removes moisture from the desiccant. This process is cyclic, due to loading of the desiccant with time, and produces air at a variable moisture content. Some desiccant dehumidification units of this design utilize multple cylinders to help offset the cyclic nature of the design. Another design utilizes a "desiccant wheel". Here a wheel of inert material with small air passages parallel with the direction of air flow contains the desiccant. (Visualize a roll of corrugated cardboard 8 to 16 inches deep) The wheel exposed a tremendous amount of surface area coated with desiccant for the air to contact. The wheel is rotated very slowly typically between 8 and 20 rph while the process and regeneration air streams pass through the wheel. With this design the process is non-cyclic as the rotating wheel is always presenting freshly regenerated desiccant to the air process air stream. A consistant moisture content of the process air is achieved. A key factor to the success of this design lies in the sealing between the two air streams. A third design uses a liquid system. A desiccant such as lithium chloride (LiCl) which has a tremendously high affinity for water is actually mixed with water in a very high concentration. This solution is sprayed into the process air and removes additional water from the air reducing the LiCl concentration before being collected in a sump. A piping and pump system moves the solution from the sump to the regeneration heater which heates the solution forcing it to release some of the water before being returned to the spray head(s). A key to successful operation of this type of system is maintaining the proper desiccant concentration. If the concentration becomes too high the solution may solidify. If it is too low the dehumidification capacity will be diminished. Due to the corrosive nature of the LiCl-water solution parts carrying the soltuion must be made of corrosion resistant material such as stainless steel. Liquid desiccant are typically used in large industrial applications.

Ingolfson (talk) 21:48, 26 January 2008 (UTC)

Do we need to reference scientific processes? I agree it is rather long though but perhaps editing it into short points and restoring it to the article might help people understand it. Lstanley1979 (talk) 19:06, 21 September 2008 (UTC)


 * Of course we do. The moment we lose vigilance, these page will fill up with people asking what happens if a humidifier and a dehumidifier are on in the same room. 74.128.56.194 (talk) 05:36, 30 May 2011 (UTC)

Dehumidification with electronoic expansion valve
in this case you don't need any heating or any change of air flow I think adding this will help interested people alot I can help if needed

mkardehi@yahoo.com mehdi.kardehi@nialimited.com —Preceding unsigned comment added by 78.158.160.27 (talk) 06:21, 16 November 2008 (UTC)

'Adsorption Technology'
some manufacturers are now marketing 'Adsorption Technology' in domestic dehumidifiers (eg Prem-i-air) using a silica gel disc. Someone with better understanding than me could enhance the article with further info as it is unmentioned within the present article.

[It may be linked to http://en.wikipedia.org/wiki/Energy_recovery_ventilation#Rotary_air-to-air_enthalpy_wheel ]

79.76.158.223 (talk) 23:03, 14 October 2009 (UTC)

Warning on Heavy Metal Content of Condensate: Unsubstantiated
[My first ever post on Wikipedia so bear with me please]

The section on Potability of dehumidifier condensate has questionable information about heavy metals in the water. It says that it should not be used to water vegetables because of the risk of lead and copper leaching from the dehumidifier's coils. This claim does not stand up to scrutiny.

1) Condensate is typically pH neutral and if acidic or alkaline at all, it would be extremely weak with no buffering and little corrosive strength.  It would not be expected to be particularly corrosive; quite the contrary. 2)  If a person watered their garden with potable water from a water supply system, the water would be exposed to the same metals in pipes and solder (especially in an older home) as it is in a dehumidifier. Yet, there are no general warnings about watering a garden with drinking water, even though there are warnings about drinking water from lead pipes and copper pipes with lead solder in older homes. This is because any amount in drinking water is so small that it will not affect the metal content of plants, and will only have an effect if consumed directly. It has to go through the soil first. The same applies to dehumidifier water. 3) Note that soils contain background levels of all these metals which typically far exceed the metal content of drinking water, or dehumidifier water (based on #2 above). It would take an enormous amount of metals added to garden soil to affect plant uptake significantly.  In fact, you could grind up an entire dehumidifier and mix it into garden soil and it would likely have no effect whatsoever.  For example, a pound of lead (let's say 500g) added to a 20x20 ft. garden 1 ft. deep (approx. 20,000 kg of soil) would result in a lead level of 25 mg/kg. This is in the range of background for many soils.  EPA and HUD suggest 400 is safe for residential use including gardening.  And there is nowhere near a pound of lead in a dehumidifier. 2)The source cited is "Treehugger.com" which does not make a technical (chemical) analysis of the question or cite any scientific sources itself. It is purely conjecture and opinion.

This article has been cited on gardening forums as an argument against using condensate for watering.

Chris Cady, Ph.D. Environmental Specialist

Agreed, there is no exposure to metal in a dehumidifier that does not occur in virtually every distribution (pipe) system in the world. If corrosion were a significant problem your dehumidifier would not last long; tube walls are very thin to promote heat flow. All of the comments made by Chris Cady are not only true, they are mostly obvious, simple common sense. The water is not only perfectly safe to water your garden with, it is probably also perfectly safe to drink especially as a minor source of water. I'm a chemist at the company that tests most of the drinking water of a major city of 3.5 million.

In addition, the term "stagnant", as used popularly, actually describes water containing organic (decomposable) matter that is not flowing and therefore has no way of replacing dissolved oxygen, and may or may not have developed a pathogenic micro-organism population, to the point where it is a health hazard. Pure water does not "go stagnant" no matter how long it stands, and for a VERY long time neither will the condensate from a dehumidifier. There would be dust present but clearly, to call water "stagnant"when it was vapour only hours previously, even goes against the word's colloquial definition. It would not contain any pathogenic micro organisms that you don't breathe in every day. The entire section on potability is full of half informed speculation that is mostly untrue. It is no surprise that the reference is Tree Hugger.

Mike.(124.170.6.214 (talk) 13:37, 14 February 2012 (UTC))

The above arguments sound reasonable but some of the conclusions are wrong. My new Fridgidaire dehumidifier has been outputting water with electrical conductivity (EC) higher than tap water in my location and a pretty acidic pH of 4.0 after processing several full reservoirs. The water makes soapy bubbles when agitated. Before I realized all this I did water my plants with the water and the skewed pH caused nutrient lockout and sick plants. I eventually traced the problem back to the dehumidifier water.

Keith — Preceding unsigned comment added by Keith 69 (talk • contribs) 08:21, 9 July 2014 (UTC)

Reorganization and cleanup
I have reorganized the article more logically, consolidated fragmented coverage, and removed badly-written and irrelevant health claims. I also removed the made-up category of "electronic dehumidifier" and replaced it by the more descriptive term "thermoelectric dehumidifier". I also added some clarification of the basic energy flows involved in refrigeration dehumidifiers. Reify-tech (talk) 18:08, 11 July 2015 (UTC)

Adsorption/desiccant dehumidification recent edit
The recent addition to the "Adsorption/desiccant dehumidification" section, beginning with "An feasibility analysis", and ending at the end of the section, appears to be lifted directly from a reference paper/study, with no adjustment for context? It makes it difficult to read, and in its current form, largely irrelevant in the context of the article. It also presents a possibly biased view, although it may well be the only source available. — Preceding unsigned comment added by Chemicalfan (talk • contribs) 12:53, 29 September 2015 (UTC)