Re: a few questions befor i go brazing.....
- Extra coil length in your condenser will make your condenser more
The amount of heat a condenser removes is related to two things.
1) the temperature difference of the cooling water from input to
output of the condenser.
2) the amount of cooling water flowing.
What a longer coil length does is allow you to maximize the
temperature difference while minimizing the flow (makes your condenser
You should operate your condenser with the minimum amount of water
flow that will completely condense the vapors. At that flow setting,
the temperature difference of the cooling water between input and
output to the condenser will determine your efficiency. If the
cooling water is NOT hot at the output of the condenser, you need more
length. If the temperature of the cooling water at the output of the
condenser is 170F, and you are condensing all the vapors then you have
a perfect condenser (not going to happen). If you can reduce the flow
so the cooling water out is burning hot to the touch and you are still
condensing all the vapors, then you have a good condenser.
If your coil is already efficient, making a longer one will not reduce
your cooling water flow.
I have two condensers that both can handle my maximum of 3000 watts
heat input to the boiler.
One condenser is a single helix of 1/4inch tubing inside a 2 inch
pipe. Each turn of the coil is spaced about 1/8inch from each other.
The length of the 2 inch pipe is about 10 inches.
The second condenser is a double helix of 1/4inch tubing inside a 2
inch pipe. The coils are again spaced about 1/8inch from each other.
The length of the 2 inch pipe is about 5 inches.
Both of these coils I run with a stainless steel scrubber packed in
the center of the coil. Otherwise the vapor passes straight through
and doesn't hang around long enough to get cooled.
I like the double helix because is doesn't require as much height.
This leaves more of the floor-to-ceiling space to be used as column.
Doing 2 coils in parallel would work, but the extra complexity isn't
worth the effort.
I have run the coils with flow in both directions. It doesn't seem to
make any difference in operation.
--- In firstname.lastname@example.org, "jestah_nz" <jestah@x> wrote:
> Befor i go brazing it all up i would like to run a few questions past
> every one out there
> firstly if i want to reduce the flow of coolant do i need to change
> the surface area of the condenser? if i make a 3m coil insted of a
> 1.5m one will i need less L/H of coolant? If this is the case what
> is eveyones opinion on double helix style coils? are they effient
> or dose the fact that the coolant flow in both diection make things
> tricky? Could having 2 coils running from bottom up be better?
> I have decided to keep the LM system as i cant return the parts to
> the shop and it will be simpler for me to just shut the VM down
> and open up the LM to collect the tails as i dont want have to take
> off the still head and move it to the side as im short and as it
> stands the thing is HUGE ... i feel so small...
> I have all the part i need for the VM condesner (80cm Liebig) but
> is this overkill since i will only be dealing with the heads and
> body not tails. Could i just get away with the 80cm 1/2 tube and
> have it passivly air cooled? maybe ad a few fins?
> lasly is it better to have the VM offtake at a downward angle? if so
> should i be going for 45 or more ? ( i will have the condesner
> virtical) and would putting a few winds of copper tube around the
> offtake (from the hot output from the top condenser keep it hot or
> as i suspect just cool it down and muck around with the