Before asking the question let me explain what I know of them.

Basically they have a wheel which is charged with a dessicant such as
Silica Gel or Lithium chloride or some other reversible hygroscopic
compound.
Air is drawn in from the room by a fan and passes through a sector of
the slowly revolving wheel which absorbs the water vapour before being
passed out again to the room in a dryer state, so far so good.

Now the water which has been absorbed by the hygroscopic material in
the wheel needs to be removed, which is done so I understand, by
heating it up in another sector of the revolving wheel which would
drive the water off in a vapour state.
The water ends up eventually in a liquid state in a reservoir which is
periodically emptied.

That being the case the sensible heat applied to increase the
temperature of the dessicant in that sector of the wheel AND the latent
heat released in condensing the water vapour must be contained in and
increases the temperature of the room. However:-

Q.) There must be another stage surely, which condenses the water
vapour to the liquid state, how is it powered ? Is it a refrigeration
coil, a peltier device or what?
How do they do it?

Don

Donwill wrote:
Before asking the question let me explain what I know of them.

Basically they have a wheel which is charged with a dessicant such as
Silica Gel or Lithium chloride or some other reversible hygroscopic
compound.
Air is drawn in from the room by a fan and passes through a sector of
the slowly revolving wheel which absorbs the water vapour before being
passed out again to the room in a dryer state, so far so good.

Now the water which has been absorbed by the hygroscopic material in
the wheel needs to be removed, which is done so I understand, by
heating it up in another sector of the revolving wheel which would
drive the water off in a vapour state.
The water ends up eventually in a liquid state in a reservoir which is
periodically emptied.

That being the case the sensible heat applied to increase the
temperature of the dessicant in that sector of the wheel AND the latent
heat released in condensing the water vapour must be contained in and
increases the temperature of the room. However:-

Q.) There must be another stage surely, which condenses the water
vapour to the liquid state, how is it powered ? Is it a refrigeration
coil, a peltier device or what?
How do they do it?

Don


The one I had was just a fan and a refrigeration coil with a container
under it to collect the water. Maybe they're more sophisticated nowadays.

Stuart Noble wrote:
Donwill wrote:
Before asking the question let me explain what I know of them.

Basically they have a wheel which is charged with a dessicant such as
Silica Gel or Lithium chloride or some other reversible hygroscopic
compound.
Air is drawn in from the room by a fan and passes through a sector of
the slowly revolving wheel which absorbs the water vapour before being
passed out again to the room in a dryer state, so far so good.

Now the water which has been absorbed by the hygroscopic material in
the wheel needs to be removed, which is done so I understand, by
heating it up in another sector of the revolving wheel which would
drive the water off in a vapour state.
The water ends up eventually in a liquid state in a reservoir which is
periodically emptied.

That being the case the sensible heat applied to increase the
temperature of the dessicant in that sector of the wheel AND the
latent heat released in condensing the water vapour must be contained
in and increases the temperature of the room. However:-

Q.) There must be another stage surely, which condenses the water
vapour to the liquid state, how is it powered ? Is it a refrigeration
coil, a peltier device or what?
How do they do it?

Don


The one I had was just a fan and a refrigeration coil with a container
under it to collect the water. Maybe they're more sophisticated nowadays.
I assume (always dangerous!) that the hot, moisture laden air then goes
into a condenser in close thermal contact with the air maybe even a heat
exchanger connected to the incoming air path which would stay at a
relatively constant temperature ie room temperature.

Bob

I did wonder if it was peltier.

However I did notice what appeared to be glass fibre covered wires
visible near the Ruby-Dry outlet. The heat output is high, so it may
simply be a heater rather than peltier (which might be insufficient re
wattage, but otherwise useful re one-side heats & one-side cools re
condensation).

If you go to the EHS (think that is the company) and look up the
exploded diagrams, X-Dry I think is on there, it will give an idea of
what is actually inside. More parts than you think from memory.

Bob Minchin wrote:
I assume (always dangerous!) that the hot, moisture laden air then
goes into a condenser in close thermal contact with the air maybe even
a heat exchanger connected to the incoming air path which would stay
at a relatively constant temperature ie room temperature.

Bob
You could be right Bob, I had a look at the EHS site as suggested by JS
bl and came across a drawing on:
http://www.prem-i-air.com/news/NewsArticle.php?aid=29
It does seem to suggest a close proximity to the inlet air.
Cheers
Don

On Feb 21, 12:34*pm, Donwill wrote:
Before asking the question let me explain what I know of them.

Basically they have a wheel which is charged with a dessicant such as
Silica Gel or Lithium chloride or some other reversible hygroscopic
compound.
Air is drawn in from the room by a fan and passes through a sector of
the slowly revolving wheel which absorbs the water vapour before being
passed out again to the room in a dryer state, so far so good.

*Now the water which has been absorbed by the *hygroscopic material in
the wheel needs to be removed, which is done so I understand, *by
heating it up in another sector of the *revolving wheel which *would
drive the water off in a vapour state.
*The water ends up eventually in a liquid state in a reservoir which is
periodically emptied.

*That being the case the sensible heat applied to increase the
temperature of the dessicant in that sector of the wheel AND the latent
heat released in condensing *the water vapour must be contained in and
increases the temperature of the room. However:-

*Q.) There must be another stage surely, which *condenses the water
vapour to the liquid state, *how is it powered ? Is it a refrigeration
coil, a peltier device or what?
How do they do it?

Don

AFAIK, and I lack experience with them, there are 2 ways the output
damp is handled. One is to just vent the hot damp air outside, the
other is to heat it hot in a small volume of air so the resulting hot
damp air is very high in moisture. Then simply cooling it to room temp
causes the precipitation, plus a small volume of damp air released.


NT