humidistatic dehumidifiers

[charlie-ia]

just out of interest, is there anything else you can use for dehumidifying a house?
I was thinking along the lines of road salt in cat litter trays, or the watergel crystals we sell in the garden centre. perhaps we could re-dry it in the sunshine.
maybe not practical on a bog i know, but there must have be situations when, for whatever reason, the usual kit cant be used? perhaps a fireman wold be the person to ask.

 

[biffvernon]

Silica gel. But you'd need an awful lot.

 

[Flyfisher]

I don't know how they did measure Rh on VCRs; I suspect the Rh sensor might have ben mounted in a similar mass of metal so that it caused local cooling of the air & so depressed the adjacent Rh.

I don't know for sure, either, but maybe they don't measure RH at all (for the good reasons you stated) because it's only the actual condensation that's the issue for camcorders.

 

[NT]

On what basis do you say that? Not that dehumidifiers need wide range sensing.

On the basis that a humidistatic dehumidifier allows a degree of control over the RH level, thereby implying it can sense a range of RH, whereas a camcorder has no such control.

That would be true for a variable humidistat, but not for a fixed setpoint one.

Or, more accurately, a camcorder is really only concerned with detecting condensation, which can cause the tape to stick to the spinning heads with unfavourable results. The actual level of RH, per se, is not a problem for camcorders. You can use them in the desert or the rainforest with equal ease.

IOW it may just detect condensation and not RH - you may have a good point there. Or it could even be just a temp sensor, a little basic electronics could then work out when condensation was a possibility.


NT

 

[NT]

I don't know how they did measure Rh on VCRs; I suspect the Rh sensor might have ben mounted in a similar mass of metal so that it caused local cooling of the air & so depressed the adjacent Rh. A cheapo new Rh sensor costs about £3.50 from Farnell.

The sensor was mounted on the head transformer assembly, ie where the problem was. This is a heffalump of aluminium and other bits. However this comes in 2 parts, stationary and spinning, and the sensor was on the stationary part, whereas damage occurs from condensation on the spinning section. Therefore as soon as condensation ceased on the sensor, the head could be spun up to dry it off rapidly if desired. Whether they were generally spun to ensure drying I dont know. Probably a penny cheaper not to bother.


NT

 

[NT]

just out of interest, is there anything else you can use for dehumidifying a house?

Wikipedia has a list of desiccants. Some are pretty cheap, eg lime, but dehydrating it requires rather high temperatures.

Silica gel is dried at low temperatures, and this is exactly how a desiccant wheel dehumidifier works.


NT

 

[Aidan]

just out of interest, is there anything else you can use for dehumidifying a house?

Also, old manuscripts and textiles will absorb moisture, the amount of moisture being directly proportional to their age and value. This phenomenon was first recorded by the ubiquitous French physicist, Monsieur Sod.

 

[biffvernon]

And of course, Thermafleece.

 

[NT]

And of course, Thermafleece.

an unusually ungreen insulator


NT

 

[biffvernon]

Yeah, kinda Herdwick Grey rather than green.

 

[NT]

and taking way more energy to produce than mineral wool.


NT

 

[biffvernon]

I know, I've seen those lambs bouncing about. Full of energy.

 

[biffvernon]

and taking way more energy to produce than mineral wool.
NT

I've just heard that Nigel Pargeter says wool insulation uses very little energy in manufacture. So that must be the truth.

 

[Nemesis]

Here it is being manufactured:

 

[NT]

If it took less energy than mineral fibre, it would be cheaper and we'd all be using it. Keeping animals for a year costs more, ie uses more energy.


NT

 

[Craig]

But you get to eat them.

 

[Craig]

Also, thats not true - it may be harder to grow sheep on an industrial scale, but that doesnt mean it absorbs more energy. Rather, sheep have cunningly evolved to die if you farm them intensively.

Its certainly does not seem like a true fact that we always pursue the lowest energy option naturally - lots of other factors influence outcomes. IMHO.

 

[MdB]

I hate the cost = energy argument as it seems silly to me in a hand waving sort of way that something is less green because it is more expensive.

However, I've been over and over the argument myself and discussed it with various people and I don't see any obvious mistakes in it. It does make sense and can be applied to a lot of things.

For the thermafleece example, the energy the goes into its production is mainly all labour (farmers, vets, sheep shearers, fleece processors, etc). All this labour uses energy to live on (cars, home heating, watching the tv etc etc.) The mineral wool on the other hand must use a lot less labour (or cheaper labour) as its costs are lower. As there is less labour, there is less energy usage overall and hence it is greener.

I hate this but can't see a flaw in the argument.

 

[NT]

I hate this but can't see a flaw in the argument.

I like it, because the truth sets us free. The truth is a required part of solutions to humankind's problems.


NT

 

[Craig]

The wool is a by-product - if we stop eating the sheep, it may be true, but as I eat sheep, its not that much effort to collect the wool. The demand for it in clothing has fallen considerably. Its also used as mulch - not a high value (energy?) item.

There are probably other issues you may wish to consider such as promoting sheep farming in the UK which has various beneficial aspects so far as I am concerned.

Rockwool is also pretty shitty stuff to work with. The wool is quite fun.

Cost = energy? Maybe. What's the interaction with capital then? Capital is not universally linked to energy, is it?