Dehumidifier sums

[Mr Gus]

AE, if you are still looking for a dehumidifier, I just ran across this in my feed..
https://www.appliancesdirect.co.uk/p/cd ... e=webgains

That's £94.96 delivered if of interest..

Has a 1.5 litre float valve internal, pull out waste storage bucket good enough for most scenarios.

No idea of the brand, nor quality, nor longevity, ..then again I bought a dimplex for £30 new.

I'll pm you as a heads up.

[AE-NMidlands]

AE, if you are still looking for a dehumidifier, I just ran across this in my feed..
https://www.appliancesdirect.co.uk/p/cd ... e=webgains

That's £94.96 delivered if of interest..

Has a 1.5 litre float valve internal, pull out waste storage bucket good enough for most scenarios.

No idea of the brand, nor quality, nor longevity, ..then again I bought a dimplex for £30 new.

I'll pm you as a heads up.

Thanks, I went ahead with the Screwfix one, was able to collect it so no courier involved (hence no damage!)

What surprises me is how little water it is extracting (it did a pint one day at the start when washing was drying, hardly anything since, although we don't leave it running all the time.)

I am sure it is working OK, and can justify the performance: the house isn't air-sealed yet and outside has been quite cold, so low absolute humidity... which when it comes in and gets warmed up becomes very low RH. SWMBO is very good about putting clothes outside to dry when there is the slightest chance of it working too - see https://camelot-forum.co.uk/phpBB3/view ... 7021#p7021

It often starts at around 62% when we switch it on and gets down to the low 50s but at that low RH there's not much latent heat to recover so I switch it off again.
We are still working on a succession of jobs which all reduce ventilation, so I guess it will become more valuable with time...
Thanks again for the alert
A

[Mr Gus]

No problem, we pull a full load every 24-48 hours it sits by the radiator which is on low, so is always able to pull as it sits above the 18 c threshold

Damp & no heat best remedied by humidifier on full whack for a few days back to back with a background heater, then run on automatic at the level you feel works best for general tick-over imho

Better with one than without.

[Stinsy]

You want the space that is being dehumidified to be as warm as possible to transfer moisture from the fabric of the building into the dehumidifier. Ours starts at 80-95% and brings it down to 55ish in a couple of hours. Drier than 45% can be uncomfortable for people.

[Oliver90owner]

You want the space that is being dehumidified to be as warm as possible to transfer moisture from the fabric of the building into the dehumidifier. Ours starts at 80-95% and brings it down to 55ish in a couple of hours. Drier than 45% can be uncomfortable for people.

Dead right. That is why I think this thread is flawed for a lot of dehumidification operations. It’s OK for moisture generated from cooking or breathing, but not much else.

Question: where did the energy come from, in order to evaporate the water collected, in the first place? The latent heat of condensation is only the same as the latent heat of evaporation to convert the damp to the gaseous phase. If the moisture being extracted is in the form of a mist, there won’t be any change of state within the dehumidifier.

Dehumidifying costs dosh. It is most certainly not a good means of heating a property! Its benefits, from the expenditure, is in avoiding mould from unwanted condensation or(in my case) avoidance of rust formation on workshop machinery. Drying clothes even means first converting liquid to vapour before collecting that vapour as liquid.

We have a heat pump condensing tumble drier. Now that is efficient - not from the latent heat of the water collected - simply by the machine recycling the warm dried air back to the machine to evaporate more water from the clothes. When up to temperature it only consumes about half a kW and doesn’t take so much longer to dry the clothes than our condensing tumble drier that simply condensed the water but threw the heat into the room.

How many produce 16 litres of collectable water vapour per day? Not many, I would think - and a lot of that will be gone by air changes on most days, I suspect.

[billi]

Well , completely agree

Dehumidifying costs dosh. It is most certainly not a good means of heating a property!

I found several Thermometer / Hydrometer combi gadgets in the rented farmhouse house , that obviously has a mold problem in the bathroom , that i do not heat , interestingly that downstairs room is about one step lower than my office and the kitchen next door where the stove is on during winter while at homeoffice about 12 yours a day . The bathrom had a humidity of 77% , and temp of 7 celsius today , living-area about 47 % and 22 celsius
Groundwater level is low here and the fields around the house are often flooded , Walls of the house are about 1.5 foot wide (500mm +) , solid sandstone rectangular cut . I know that those stone let moisture travel up from the ground at least 1-2 meter in the wall due tocapillarity and maybe osmosis too . Thats how plants and their cells work too , that the salt or fertilizer content in the ground is higher than in the upper plant parts , so each cell in the plant transfers liquid with an higher salt content in the next one up with lower salt content to balace them out , thats how food is traveling in plants https://en.wikipedia.org/wiki/Osmosis
I am just thinking loud and its just an theory ( might be rubbish ) as the land around me is probably(for sure) fertilized and those floods of that land will wash even more ferilizer/salt) into the ground ....

Well ... i have to consider a more mechanical way of dealing with that moisture in the wall and in the floor .
Common practice here with similar old houses , is to cut the complete walls with a machine and slide in that cut slot , a non permeable sheet .
Other method is drilling holes in the low part of the wall and stick penetrating injectors in those, filled with a special (silicon based ?) to seal those walls better .
Well first of all i need a digger and get rid of the soil attached to those foundation/wall stones

Well, i know its not your problem , but that dehumidifier threat made me think more about it , if they would be a solution , but i think/know it would fool the reality of dryness,and that the walls might/will be still soaking wet and would not help the overall structure and further development of that house or other old houses .

But it might be an idea just as a temporary install in the bathroom , as i am not willing to switch the 70 th installed electric heater on, in there

Regarsd Billi

PS that armada of gadgets now all on my table now , collected from different rooms and in-between an hour, they get closer results now , did not expect that they need so much time to acclimatize

[Marcus]

Dehumidifying costs dosh. It is most certainly not a good means of heating a property!

Agreed (had to go back to the original post to remind myself what the original topic was), but with one caveat:

If you're using an electric heater (or worse one of those portable gas heaters) in a shed/outbuilding to keep the mold at bay, then that's going to cost more dosh than running a dehumidifier. I think i said something about heating the caravan i'm living in with the dehumidifier - but that's 'cos I typically have >300w hydroelectric to run it and the alternative is burning gas.

[Moxi]

So we had some spare sunshine around 4pm so I got the calcium chloride solution out and put the pan on the trusty crofton electric ring outside and started to boil off some of the captured water, I had it boiling / simmering for around two hours and the liquid level dropped by around 15mm then because the clouds started to appear I knocked off the heat and started to cool the liquid down. After only a few minutes I started to see crystallisation sites and within 15 minutes the pan looked as per the photo above.

Using an old spoon and plastic tub I scooped off the crystallised material and the thick gloop underneath it, the watery material with a wall paper paste consistency was poured back into the screw top container to have fresh hydrated calcium chloride added to it for another time.

The tub was almost too hot to hold and the temp was check at 80.5 degrees and three hours later it was still comfortably warm to touch. I read later that it’s an exothermic reaction when rehydrating so it could have multiple uses but don’t forget it’s a halide and can cause skin irritation and burning to soft tissue in the eyes the mouth and throat so be safe and use the correct Poe and safety measures.

The material I recovered has set into a greyish block indicating that it still has some water in it so on the next fine day it will be broken into smaller bits and oven dried further to get closer to its anhydrous state.

But I have to say that it’s probably a net benefit as it’s easy to do once you have the tools and techniques you can reuse your desiccant and tubs time and time again.

Moxi

[AE-NMidlands]

Dehumidifying costs dosh. It is most certainly not a good means of heating a property!

Agreed (had to go back to the original post to remind myself what the original topic was), but with one caveat:

If you're using an electric heater (or worse one of those portable gas heaters) in a shed/outbuilding to keep the mold at bay, then that's going to cost more dosh than running a dehumidifier. I think i said something about heating the caravan i'm living in with the dehumidifier - but that's 'cos I typically have >300w hydroelectric to run it and the alternative is burning gas.

Sorry, I missed this when first posted...
the portable gas heaters are a disaster where humidity is concerned. They produce more water vapour than CO2 and without a flue to outside will give you a condensing atmosphere. Ditto paraffin: I know model engineers who regretted putting paraffin heaters in their workshops because of the corrosion damage they caused. Also a neighbour used gas heaters before they had central heating -and put silicone all over the outside of the solid walls of their house, I think because they misinterpreted where the moisture was coming from.

The tub was almost too hot to hold and the temp was check at 80.5 degrees and three hours later it was still comfortably warm to touch. I read later that it’s an exothermic reaction when rehydrating so it could have multiple uses but don’t forget it’s a halide and can cause skin irritation and burning to soft tissue in the eyes the mouth and throat so be safe and use the correct Poe and safety measures.

Moxi

I remember that dissolving CaCl gets very cold, but I can't remember why I was doing it. Maybe we needed a high-density brine for something...

[Moxi]

So I popped over to the shed in between the rain showers to check the gloop and imagine my surprise when under the lid I found this slab of white calcium chloride. Approximately 15 cm by 10 cm by 2 cm and weighing in at approx 750 g so I’m guessing still got moisture locked in.

As previously stated next step is to break it up and give it some more warmth to dry it further.

The cast nature of the block has got me wondering about a design for a dehumidifier using sheets of CaCl2 hung in vertical wire frames above a drip tray - the water would then run down the sheet to the tray and saves breaking up and trying to granulate the material ??

Will have to think about that ?

Moxi