matt, close but no cigar. the unit needs to be more or less vertical so that
the liquid drains all the way back to the burner. If the liquid does not get
back there they burner pot gets scorched and the unit is ruined.

but yes, a cigar regarding efficiency. gas absorbtion refrigerators are much
less efficient than compressor reefers, when comparing energy input vs cooling
capacity. One a boat, electricity is incredibly expensive to make per
kilowatt, and HUGELY expensive compared to the same kilowatt purchased as
propane.

A kilowatt of electricity produced on a boat can cost $2 to $5 dollars EACH,
while a gallon of propane (about 90,000 btu's, or about 30 kilowatts) goes for
maybe a couple bucks (? I can't remember how much I paid for 10# of propane
last summer, but it certainly was pocket change)

You people seem to have missed two things in the thermodynamics part of
your education.

A Servel Cycle (the identifier for water/hydrogen/ammonia abortion
refrigeration) requires both the persistance of two liquid/vapor seals
and a lot of vertical room.

The vertical height is required so the ammonia can get condensed and
then be run down into the evaporator by gravity.

The two sealing loops separate a: ammonia vapor from ammonia liquid and
hydrogen and b: water from hydrogen.

The "household" units - these include RV - do not have seals that work
well out of vertical. Seals for these have been designed that do just
fine at a considerable offset. If the seals get blow out, they will
re-establish themselves with a reasonable amount of running time.

A one time I was employed by a company that was in the process of
developing a refrigeration system that could used the exhaust heat of an
RV to be the motivating heat for the refrigeration (apart from the fact
that the system had real flexability issues as far as installaion) the
whole program went down in flames whent he bottom fell out of the RV
market during the original Arab Oil Embargo.

Another issue for sailors would be that the COP (co-efficient of
performance - sort of the effieciency) of Servel units was not as good
as an R12 or R22 unit.

Matt Colie


Horace Brownbag wrote:
On 04 Jul 2004 02:05:22 GMT, (JAXAshby) wrote:


The
real problem with absorption cycle refrigeration (gas refrigerators) is
that they must stay within 5 to 7 degrees of vertical.

not true. unless the vehicle is NOT moving side to side.


lateral forces mimic inclination.

Jax,

I kind of hate to tell you this, but maintaining the liquid fill in the
generator (you called a burner pot?) is actually pretty simple. We
managed to blow that one away early in the program. With the correct
mixer - generator layout and connection it will function properly at
latteral loads to 1g (project design standard). Wouldn't that would be
close to a 45 deg heel? other thread

The last people that called me about this project a couple of years ago
bought consulting time that produced a spreadsheet that laid out all the
costs and benefits. They were looking at a system to include in
powerboats. Ventilation became a serious issue. That would still be an
issue in good boats. The potential to power the refrigation with
alternative power generation (solar, wind, towfish) were of no interest
to them. The fact that the unit could be run on waste heat from a
modified exhaust manifold did not get anything because the hours at
design load were not there (planing hull). The potential to fuel it
with diesel still did not win the game.

The COP is the game killer. The required ventiation is next. Never
mind that the system has not moving parts and can not wear out.

Matt Colie - See Prior Sigs



JAXAshby wrote:
matt, close but no cigar. the unit needs to be more or less vertical so that
the liquid drains all the way back to the burner. If the liquid does not get
back there they burner pot gets scorched and the unit is ruined.

but yes, a cigar regarding efficiency. gas absorbtion refrigerators are much
less efficient than compressor reefers, when comparing energy input vs cooling
capacity. One a boat, electricity is incredibly expensive to make per
kilowatt, and HUGELY expensive compared to the same kilowatt purchased as
propane.

A kilowatt of electricity produced on a boat can cost $2 to $5 dollars EACH,
while a gallon of propane (about 90,000 btu's, or about 30 kilowatts) goes for
maybe a couple bucks (? I can't remember how much I paid for 10# of propane
last summer, but it certainly was pocket change)


You people seem to have missed two things in the thermodynamics part of
your education.

A Servel Cycle (the identifier for water/hydrogen/ammonia abortion
refrigeration) requires both the persistance of two liquid/vapor seals
and a lot of vertical room.

The vertical height is required so the ammonia can get condensed and
then be run down into the evaporator by gravity.

The two sealing loops separate a: ammonia vapor from ammonia liquid and
hydrogen and b: water from hydrogen.

The "household" units - these include RV - do not have seals that work
well out of vertical. Seals for these have been designed that do just
fine at a considerable offset. If the seals get blow out, they will
re-establish themselves with a reasonable amount of running time.

A one time I was employed by a company that was in the process of
developing a refrigeration system that could used the exhaust heat of an
RV to be the motivating heat for the refrigeration (apart from the fact
that the system had real flexability issues as far as installaion) the
whole program went down in flames whent he bottom fell out of the RV
market during the original Arab Oil Embargo.

Another issue for sailors would be that the COP (co-efficient of
performance - sort of the effieciency) of Servel units was not as good
as an R12 or R22 unit.

Matt Colie


Horace Brownbag wrote:

On 04 Jul 2004 02:05:22 GMT, (JAXAshby) wrote:



The
real problem with absorption cycle refrigeration (gas refrigerators) is
that they must stay within 5 to 7 degrees of vertical.

not true. unless the vehicle is NOT moving side to side.


lateral forces mimic inclination.

On Sun, 04 Jul 2004 22:31:17 -0400, Matt Colie
wrote:
snip
The COP is the game killer. The required ventiation is next. Never
mind that the system has not moving parts and can not wear out.

I hunted for years for a Servel for my rural home. I finally found
one, not ready to pay thousand or so bucks for a new one.

The damn thing was 50 years old. It looked new. I dropped it in.

My electric went down 20 bucks a month, and my propane went up 5...and
only on the quieter winter nights could I hear the flame going.... I
heated with wood; what did I care if the power went out? Which
doesn't mean anything except I thought it was cool.

It was not as fast to recover, not as spacious, nor was the interior
design up to today's standards, but built like a tank. I hated to
part with it.

I hunted for years for a Servel for my rural home. I finally found
one, not ready to pay thousand or so bucks for a new one.




A little OT, but when I was growing up in coastal New England, my parents
got a Servel. When we had bit storms or a hurricane, it was over loaded with
stuff from the neighbors that were without electricity. I lived for a time
in the Cleveland National Forrest, in southern Californian, and the little
cottage had one that was run off our propane tank.

I kind of hate to tell you this, but maintaining the liquid fill in the
generator (you called a burner pot?) is actually pretty simple.

yup, I think I said that right from the start, as long as the boat is rocking
around a bit, but NOT in an RV parked off level more than a few degrees.

it will function properly at
latteral loads to 1g

more than 1 g actually. much more.

Wouldn't that would be
close to a 45 deg heel?

no. lateral loads and degree heel are not interchangeable terms in this issue.

The last people that called me about this project a couple of years ago
bought consulting time

ah, THAT proves you are knowledgeable, doesn't it. someone paid you money to
hear you talk.

They were looking at a system to include in
powerboats.

then they were wasiting their time. powerboats have excess power available
compared to the power needs of a reefer system.

Ventilation became a serious issue. That would still be an
issue in good boats.

nah, a propane reefer has such a tiny flame is hard to tell the unit is running
unless you hold your hand over the chimney for upwards of thirty seconds or
more.

Jax,
I'm on the way to another job and going to take this time to respond
in-line (a method I personally do not choose)

JAXAshby wrote:
I kind of hate to tell you this, but maintaining the liquid fill in the
generator (you called a burner pot?) is actually pretty simple.

yup, I think I said that right from the start, as long as the boat is rocking
around a bit, but NOT in an RV parked off level more than a few degrees.

In the prior note you said this would be tough to do. Our program
target was 1g latteral without blowing the seals and we quickly
discovered that if it did that the operation would be satisfactory at
any any acceptable for and RV. One of my pepole decide to see how far
out of verticle the last protoype could be fired and remain operational.
The rig he built could only do 27deg. He is still using that unit in
his RV.


it will function properly at latteral loads to 1g

more than 1 g actually. much more.

I was not aware that you were part of our team and setting our design goals.


Wouldn't that would be close to a 45 deg heel?

no. lateral loads and degree heel are not interchangeable terms in this issue.

Can you please tell us why not?


The last people that called me about this project a couple of years ago
bought consulting time

ah, THAT proves you are knowledgeable, doesn't it. someone paid you money to
hear you talk.

When was the last time someone paid you for your opinion?


They were looking at a system to include in powerboats.

then they were wasiting their time. powerboats have excess power available
compared to the power needs of a reefer system.

Many smaller powerboats do not have a ship's service generator. Many
also do not have very extensive DC as they are running the alternator
that cmae with the engine package.

Ventilation became a serious issue. That would still be an
issue in good boats.

nah, a propane reefer has such a tiny flame is hard to tell the unit is running
unless you hold your hand over the chimney for upwards of thirty seconds or
more.

If you are so sure, please close yourself in a boat cabin with a fire
going for a day. You might notice the moisture accumuation that is a
by-product of combustion before the oxygen depletion is apparent.

Nice talking to you, I have to go.

Matt Colie
www.southpointechandler.com