On Wed, 22 Aug 2007 08:06:46 -0400, "Roger Long"
wrote:


"Larry" wrote

Distilled water has none of these problems. What I can't figure out,
especially on power yachts, is why all that waste engine heat going up
the stacks isn't running engine-room-mounted distillers for fresh water
to drink.

You are spot on with this comment. When I was working at Woods Hole, in the
days before reverse osmosis, they had an engineer who knew how to tweak the
waste heat vacuum distillation units to the point that they got a gallon of
fresh water for every gallon of fuel burned; that's after the fuel had
pushed the ship or made electricity.

Take a look at the power draw for a reverse osmosis unit and then figure out
how much "fresh water" you have to carry in the form of fuel.

It a size/expense issue as much as anything else. Navy boilers
commonly used "economizers" to preheat boiler feed water, but
they were fairly massive units sitting in the stacks.
Evaporators aren't exactly mini me's either.
I think a look at the heat exchangers used to provide heated water
might give some idea on what's involved.
Heck, you already don't have space to use your engine crank.
It sure would be fun to tinker with. For a sailboat I'd probably look
at rain collectors, solar stills, and bottled water first.
I've sometimes wondered why IC engine designers haven't yet come
up with an engine that can't better utilize the BTU's in the fuel
instead of throwing it away via heat. Think of those millions of
engines out there wasting all of that energy from radiators, hoses,
heads and blocks.

--Vic

On Wed, 22 Aug 2007 07:40:38 -0500, Vic Smith
wrote:

On Wed, 22 Aug 2007 08:06:46 -0400, "Roger Long"
wrote:


"Larry" wrote

Distilled water has none of these problems. What I can't figure out,
especially on power yachts, is why all that waste engine heat going up
the stacks isn't running engine-room-mounted distillers for fresh water
to drink.

You are spot on with this comment. When I was working at Woods Hole, in the
days before reverse osmosis, they had an engineer who knew how to tweak the
waste heat vacuum distillation units to the point that they got a gallon of
fresh water for every gallon of fuel burned; that's after the fuel had
pushed the ship or made electricity.

Take a look at the power draw for a reverse osmosis unit and then figure out
how much "fresh water" you have to carry in the form of fuel.

It a size/expense issue as much as anything else. Navy boilers
commonly used "economizers" to preheat boiler feed water, but
they were fairly massive units sitting in the stacks.
Evaporators aren't exactly mini me's either.
I think a look at the heat exchangers used to provide heated water
might give some idea on what's involved.
Heck, you already don't have space to use your engine crank.
It sure would be fun to tinker with. For a sailboat I'd probably look
at rain collectors, solar stills, and bottled water first.
I've sometimes wondered why IC engine designers haven't yet come
up with an engine that can't better utilize the BTU's in the fuel
instead of throwing it away via heat. Think of those millions of
engines out there wasting all of that energy from radiators, hoses,
heads and blocks.

The only distillation unit I've seen was one that used the engine to
heat the water also used the engine to drive a vacuum pump to lower
the pressure in the distillation chamber. and I suspect that is how
you would have to do it on a smallish boat. I wasn't primarily
responsible for maintenance on the damned thing but got lumbered with
working on it as I seemed to be the only one at the site that would
admit to understanding its theory of operation. Either I was the only
smart one or the only dumb one (for admitting I understood the beast).
When I left the project water was still a problem at that site.





Bruce in Bangkok
(brucepaigeATgmailDOTcom)

That is consistent with what I observed. The units were about the size of a
25 KW generator and required a lot of understanding and tweaking to function
properly. The reason it came to my notice was everyone's amazement that the
engineer was able to get more water out than even the manufacturer
(DeLaval?) thought possible.

This wouldn't be a current option unless someone were to produce a scaled
down unit for trawler yacht size boats. Even larger craft have gone largely
to reverse osmosis because they are less troublesome to run and manage.

--
Roger Long

"Roger Long" wrote in news:46cc4cf3$0$18928
:

Even larger craft have gone largely
to reverse osmosis because they are less troublesome to run and manage.



You can tell the Love Boat industry has gone to RO because of the number of
people who have been poisoned drinking it.



Larry
--

On Wed, 22 Aug 2007 18:42:08 +0000, Larry wrote:

"Roger Long" wrote in news:46cc4cf3$0$18928
:

Even larger craft have gone largely
to reverse osmosis because they are less troublesome to run and manage.



You can tell the Love Boat industry has gone to RO because of the number of
people who have been poisoned drinking it.



Larry

Not necessarily so Larry, We had 3, 3,000 gal/day R.O units on oil
production barges in the Java sea for about 5 years. While I agree
that they require maintenance they were far easier to maintain then
the exhaust heater and vacuum chamber distillation plant I maintained
in Irian Jaya.

The installations we had were commercial units with detailed operation
manuals. We simply followed the schedule for back flushing and
cleaning the membranes and they produced drinkable water for the
entire period we used them. We know that as we took weekly samples
from the tanks and had them laboratory tested as part of our
contractual obligations with the client.

On the other hand, people who either don't know, or don't care what
equipment they have and how to maintain it shouldn't use it.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

wrote in news:8fqpc31amu1btj9jpfltdtuoo244e4b94h@
4ax.com:

We simply followed the schedule for back flushing and
cleaning the membranes and they produced drinkable water for the
entire period we used them. We know that as we took weekly samples
from the tanks and had them laboratory tested as part of our
contractual obligations with the client.


Wouldn't it be fun to try to look at the lab reports on RO water from a
cruise ship that's in port just long enough to pickup supplies and the next
load of suckers for the craps tables.

Larry
--

On Thu, 23 Aug 2007 02:18:33 +0000, Larry wrote:

wrote in news:8fqpc31amu1btj9jpfltdtuoo244e4b94h@
4ax.com:

We simply followed the schedule for back flushing and
cleaning the membranes and they produced drinkable water for the
entire period we used them. We know that as we took weekly samples
from the tanks and had them laboratory tested as part of our
contractual obligations with the client.


Wouldn't it be fun to try to look at the lab reports on RO water from a
cruise ship that's in port just long enough to pickup supplies and the next
load of suckers for the craps tables.

Larry

Yes, it might well be enlightening. We did the lab testing because we
had to do it and report the results to ARCO on a weekly basis. One
assumes that they had some water problems in the past.

Another point was they we were 50 - 60 miles off shore and took our
water from roughly the depth of the barge. i.e., the intakes were in
the bottom of the one of the tanks so were feeding the thing with the
cleanest water available to us.

Interestingly the only major problem we had with the units, other then
sucking up a load of oily water before we moved the intakes, were the
seals in the high pressure pumps which were made in England. But as we
had a coupl;e of guys who crew changed to the U.K. we just had them
hand carry a bunch of seals back every time they returned from break.

By the way, I have a mate who is into the distilling business,
although he distills a mixture of sugar and water:-). What kind of
still are you using? A simple pot still or a reflux unit?


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

Vic Smith brought forth on stone tablets:
On Wed, 22 Aug 2007 08:06:46 -0400, "Roger Long"
wrote:


"Larry" wrote


Distilled water has none of these problems. What I can't figure out,
especially on power yachts, is why all that waste engine heat going up
the stacks isn't running engine-room-mounted distillers for fresh water
to drink.

You are spot on with this comment. When I was working at Woods Hole, in the
days before reverse osmosis, they had an engineer who knew how to tweak the
waste heat vacuum distillation units to the point that they got a gallon of
fresh water for every gallon of fuel burned; that's after the fuel had
pushed the ship or made electricity.

Take a look at the power draw for a reverse osmosis unit and then figure out
how much "fresh water" you have to carry in the form of fuel.


It a size/expense issue as much as anything else. Navy boilers
commonly used "economizers" to preheat boiler feed water, but
they were fairly massive units sitting in the stacks.
Evaporators aren't exactly mini me's either.
I think a look at the heat exchangers used to provide heated water
might give some idea on what's involved.
Heck, you already don't have space to use your engine crank.
It sure would be fun to tinker with. For a sailboat I'd probably look
at rain collectors, solar stills, and bottled water first.
I've sometimes wondered why IC engine designers haven't yet come
up with an engine that can't better utilize the BTU's in the fuel
instead of throwing it away via heat. Think of those millions of
engines out there wasting all of that energy from radiators, hoses,
heads and blocks.

Take a look at the Crower 6-cycle engine -

bob
s/v Eolian
Seattle

RW Salnick wrote in news:fai0c9$f20$1
@gnus01.u.washington.edu:

Crower 6-cycle engine

A GREAT idea!

What would we do with all those fans in the engine rooms??...(c;

Larry
--

On Wed, 22 Aug 2007 11:47:35 -0700, RW Salnick
wrote:



Take a look at the Crower 6-cycle engine -

Although I didn't look closely, it almost reminds me of a variation of
"water injectors." A non-closed steam circuit doesn't make sense to
me, and once the steam circuit is closed, we're back to the latter
Stanley Steamers, although they could be much improved with turbines.
Anyway, the IC and steam don't seem to mix become of the volume steam
requires.
Since you kept me interested, I found "bmw steam assist"
which is more along the lines I was thinking in recovering waste heat.
The trick is designing a practical heat recovery device that is
adequately efficient in heat transfer, energy conversion, and power
train while still being small in size. And the cost, of course.
I don't think it would actually use water, but something more exotic.
Again I didn't read deeply, but they seem on the right track.
Except - to get the most out this I think it needs to be hybridized to
the extent that when excess heat isn't being used to apply motive
power, that energy should be shunted to a battery for storage.
So it would be a step beyond current gas/battery hybrids, but still
need that honking battery. Another alternative way of storing energy
I recall reading about is the massive flywheel - I think vacuum sealed
- which stores braking energy and feed it back when needed.
Sounded nice until you think of the weight and vacuum required,
or the high-speed flywheel shattering and spraying shrapnel.
Another thought is that the great increase in IC fuel efficiency
has been achieved mostly by better burning of fuel with injectors,
electronic ignition, etc. There might be more bounty in squeezing
the most out of the fuel and working on getting the explosion
itself to transfer more of its direct energy into work.
Though it's heat transfer instead of work, modern home NG furnaces
are up to about 90% efficiency and use PVC exhaust vents.
Wankel was the last radical IC redesign I'm aware of, but there
may be a genius out there that comes up with another that completely
changes our thinking about this.
It won't be me - writing this has wrung me out.

--Vic