Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #11   Report Post  
Doug Dotson
 
Posts: n/a
Default


"Terry Spragg" wrote in message
...
Jeff wrote:

Again, this may be true, but it might not be appropriate for all systems.
Adding a thru-hull and more components probably isn't worth a few
Amp-hours savings.

From Richard Kollman's site:

28. Question: Why would I want air cooling when water is more efficient?

Answer: Boat refrigeration systems smaller than ¼ HP are generally air
cooled for best performance and long term reliability. There are few
conditions where the seawater cooling can out perform air cooling on
these small units. To dispose of the heat in a boat from a small Danfoss
refrigeration system is about the same as disposing of the heat generated
from one person onboard, three hundred BTUs per hour. It is true that
heat from larger refrigeration systems must use seawater because the heat
can not be disposed adequately of onboard a boat.

http://www.kollmann-marine.com/answers.html#28


And, what kind of pump is only a half Amp? Most of the circulating pumps
for DC belt driven systems seem to take an Amp or more. The traditional
March 809, for example, is rated at 1.5 Amps. Of course, the pump for a
Danfoss system could be much smaller.

Doug Dotson wrote:

The water pump on my system draws less than 1/2 amp. Using a
water-cooled
system saves enough energy to more than offset the overhead of the pump.

Doug

"Jeff" wrote in message
...

It may be true that water cooled is usually more efficient, but for a
minimal system based on a BD35, the added efficiency may not be worth
the power use of a water pump. This is a small issue with a large
holding plate system because it only runs one or two hours a day, but
the small evaporator based system may run 8 hours a day, and the water
pump would then add a lot of overhead. And, it adds a through-hull,
strainer and plumbing, and can get clogged with silt. This may be
worthwhile Downeast, where the water is 52 degrees, but might not be in
the tropics.

Doug Dotson wrote:

A water-cooled unit is always more efficient than an air-cooled unit.
Unless
somehow the air temp gets cool for a long period while the water temp
stays
high. Not very common. This is why all the larger units are
water-cooled.

Doug
s/v Callista


"Jeff" wrote in message
...


A lot depends on the size of your fridge and how you use it. If you
can go into a bit of detail, such as the size of the box(es), freezer
requirements, and the nature of your cruising, you might get better
advice. For example, if you cruise in cold water, a water cooled
system would be more efficient. But if you power each day (or run a
genset for A/C) then the power issues might not be important to you.

I have larger Crosby (actually part of A/B) holding plate system for
a separate fridge and freezer system that I've had a love/hate
relationship with. When I pull a steak out of the freezer that's
frozen down to zero degrees, I'm happy. But when I don't need the
freezer, its a real annoyance to use 70 to 100 Amp-hours a day on the
system. And of course, one small leak and the whole system is down.
(This happened twice in 7 seasons, and both times was detected in
home port, not while traveling.)

If I were building my system now, I might consider having two systems
based on the new Danfoss compressors. While perhaps not the most
efficient in total, having two systems for the two boxes would give
more flexibility in case one is lost.

Danfoss is the "hermetic" sealed compressor your A/B is based on, and
is used in most of the smaller systems today. Of course, the units
have changed in the last 20 years, and each company has some "special
technology" that makes theirs the best. You might look over
www.rparts.com to get a free education about the components in use
today. They carry the latest Danfoss units and this will give you a
baseline to see if you're getting your money's worth from whichever
system you decide on.





Dick Behan wrote:


The 20-year-old Adler/Barbour unit on our Victory Tug has expired.
Can't complain about the service, but what do you cruisers out there
think about replacing it? Go with Adler/Barbour again, or is there
a more up-to-date technology (and product) you'd recommend as
superior?
TIA.

Dick Behan
M/V ANNIE





My little electric frige has a warm plate at the rear, more or less
surrounded by cabinetry. My engine room vent inlet passes nearby. I
wonder if venting the warm plate to the vent pipe using a dryer air box
switch might provide some benefits during warm or even cold weather,
depending on the airbox switch?


First, would such a vent improve the efficiency of my frige?


As long as the air you are providing is cooler that what it would otherwise
see.

I am presuming that the engine would suck in the frige heat without any
complications, and that there is enough rise in the intake side for when
the engine is asleep. Hmmm.


Hmmmm is right

Would I benefit from blowing a fan into the open frige on a hot night?
Maybe cooling down just for long enough to doze off in the saloon table
hammock?


You're kidding, right?

Terry K



  #12   Report Post  
Doug Dotson
 
Posts: n/a
Default


"jeannette" wrote in message
...
On Wed, 17 Aug 2005 20:01:57 -0400, Jeff wrote:

It may be true that water cooled is usually more efficient, but for a
minimal system based on a BD35, the added efficiency may not be worth
the power use of a water pump. This is a small issue with a large
holding plate system because it only runs one or two hours a day, but
the small evaporator based system may run 8 hours a day, and the water
pump would then add a lot of overhead. And, it adds a through-hull,
strainer and plumbing, and can get clogged with silt. This may be
worthwhile Downeast, where the water is 52 degrees, but might not be
in the tropics.


The solution is: "Isotherm SP" for self pumping cooling with no moving
parts. I have one for 2 years now and it never missed a bit.

http://www.e-marine-inc.com/products...ation/faq.html

Jeannette
Bristol 32, San Carlos, Mexico
http://www.eblw.com/contepartiro/contepartiro.html


Looks like a system much like the Frikkin-Boat except the heat enchanger
in in the sink drain. OK for a small systems.

Doug
s/v Callista


  #13   Report Post  
DSK
 
Posts: n/a
Default

Jeff wrote:
Again, this may be true, but it might not be appropriate for all
systems. Adding a thru-hull and more components probably isn't worth a
few Amp-hours savings.


It's more than that... water cooling may save a lot o' bucks by using a
smaller unit. And it's more desirable in the tropics, where the ambient
air temp is higher. As air temp gets above the 80s, trying to air cool a
refrig'n condenser gets to be a losing proposition.

Another alternative is the keel cooler. At least two companies now are
making thru-hulls chambered & fitted for refrigeration keel cooling, so
you don't have to drill any more holes in your hull.

Some may be interested in my current project, 98% complete at this
point: installing a freezer built into our dinette seat. After a LOT of
research and spreadsheeting all the numbers, I decided on a Waeco
(Adler-Barbour) CU-84 (based on the Danfoss BD-35) air cooled
refrigeration unit, with an exhaust to the outside. The box is insulated
on 5 sides with R-28 vacuum panels. I am currently finishing the lids, a
relatively demanding bit of fiberglassing that I don't recommend.
http://community.webshots.com/photo/...89712634CcPfiT
(next 7 pics)

Fresh Breezes- Doug King

  #14   Report Post  
Jeff
 
Posts: n/a
Default



DSK wrote:
Jeff wrote:

Again, this may be true, but it might not be appropriate for all
systems. Adding a thru-hull and more components probably isn't worth
a few Amp-hours savings.


It's more than that... water cooling may save a lot o' bucks by using a
smaller unit. And it's more desirable in the tropics, where the ambient
air temp is higher. As air temp gets above the 80s, trying to air cool a
refrig'n condenser gets to be a losing proposition.


So you chose air cooled. How come?

One of the little ironies is that in cold water, the air in the bilge
may be much cooler than on deck or in the engine room. I never
bothered to measure, but I wonder if that's also true in the tropics.

As for savings - the cost difference between the BD50 and BD35 is
pretty small - certainly much less than a through hull, pump, and
condenser. However, once you get larger its clear that water cooling
has advantages.

BTW, my father-in-law, an HVAC engineer and inventor, rigged up his
home A/C to heat the swimming pool water with the waste heat. It
worked great for a number of years, but now that he's 84 and his war
injuries have caught up to him, he has trouble maintaining it. With
the extra plumbing, its possible to loose the pool water, and then be
without both pool and A/C.


Another alternative is the keel cooler. At least two companies now are
making thru-hulls chambered & fitted for refrigeration keel cooling, so
you don't have to drill any more holes in your hull.

Some may be interested in my current project, 98% complete at this
point: installing a freezer built into our dinette seat. After a LOT of
research and spreadsheeting all the numbers, I decided on a Waeco
(Adler-Barbour) CU-84 (based on the Danfoss BD-35) air cooled
refrigeration unit, with an exhaust to the outside. The box is insulated
on 5 sides with R-28 vacuum panels. I am currently finishing the lids, a
relatively demanding bit of fiberglassing that I don't recommend.
http://community.webshots.com/photo/...89712634CcPfiT
(next 7 pics)


I like this setup. As I've mentioned before, using one compressor for
both fridge and freezer can be a problem. The BD35 gives a lot of
bang for the buck.



Fresh Breezes- Doug King

  #15   Report Post  
Doug Dotson
 
Posts: n/a
Default


"Jeff" wrote in message
...


DSK wrote:
Jeff wrote:

Again, this may be true, but it might not be appropriate for all
systems. Adding a thru-hull and more components probably isn't worth a
few Amp-hours savings.


It's more than that... water cooling may save a lot o' bucks by using a
smaller unit. And it's more desirable in the tropics, where the ambient
air temp is higher. As air temp gets above the 80s, trying to air cool a
refrig'n condenser gets to be a losing proposition.


So you chose air cooled. How come?

One of the little ironies is that in cold water, the air in the bilge may
be much cooler than on deck or in the engine room. I never bothered to
measure, but I wonder if that's also true in the tropics.

As for savings - the cost difference between the BD50 and BD35 is pretty
small - certainly much less than a through hull, pump, and condenser.
However, once you get larger its clear that water cooling has advantages.

BTW, my father-in-law, an HVAC engineer and inventor, rigged up his home
A/C to heat the swimming pool water with the waste heat. It worked great
for a number of years, but now that he's 84 and his war injuries have
caught up to him, he has trouble maintaining it. With the extra plumbing,
its possible to loose the pool water, and then be without both pool and
A/C.


Another alternative is the keel cooler. At least two companies now are
making thru-hulls chambered & fitted for refrigeration keel cooling, so
you don't have to drill any more holes in your hull.

Some may be interested in my current project, 98% complete at this point:
installing a freezer built into our dinette seat. After a LOT of research
and spreadsheeting all the numbers, I decided on a Waeco (Adler-Barbour)
CU-84 (based on the Danfoss BD-35) air cooled refrigeration unit, with an
exhaust to the outside. The box is insulated on 5 sides with R-28 vacuum
panels. I am currently finishing the lids, a relatively demanding bit of
fiberglassing that I don't recommend.
http://community.webshots.com/photo/...89712634CcPfiT
(next 7 pics)


I like this setup. As I've mentioned before, using one compressor for
both fridge and freezer can be a problem. The BD35 gives a lot of bang
for the buck.



Fresh Breezes- Doug King


I've gotten great service out of my spillover system. Cold plates in the
freezer only.
Thermostacally controlled vent into the fridge side. Large boxes. Probably 3
cuft
in the freezer and 12 cuft in the fridge.

Doug
s/v Callista




  #16   Report Post  
Jeff
 
Posts: n/a
Default

Doug Dotson wrote:
I like this setup. As I've mentioned before, using one compressor for
both fridge and freezer can be a problem. The BD35 gives a lot of bang
for the buck.

I've gotten great service out of my spillover system. Cold plates in the
freezer only.
Thermostacally controlled vent into the fridge side. Large boxes. Probably 3
cuft
in the freezer and 12 cuft in the fridge.


Then you really don't have a two box system. And, as with mine, you
have no way to run the fridge only. If you truly had two boxes with
two compressors, as I assume DSK has, then you have the option of
shutting down the freezer to save energy, plus you have a backup.

I have nothing against spillover systems, and your compressor system
is probably almost identical to mine. I'm just pointing out
possibilities that might work for different situations.


  #17   Report Post  
DSK
 
Posts: n/a
Default

"Jeff" wrote
So you chose air cooled. How come?


Smaller cheaper unit, plus my confidence in my ability to post-engineer
a seawater assisted cooling unit from either of the two already existing
seawater systems on board.

One of the little ironies is that in cold water, the air in the bilge may
be much cooler than on deck or in the engine room. I never bothered to
measure, but I wonder if that's also true in the tropics.


I'm sure it is. There would be at least a little cooling effect on air
flowing into the bilge and then up thru the condensor... and presumably,
thence overboard. It would help ventilate an area that prob'ly needs it,
too.


As for savings - the cost difference between the BD50 and BD35 is pretty
small - certainly much less than a through hull, pump, and condenser.
However, once you get larger its clear that water cooling has advantages.


Actually the difference in price between the two Waeco units... the one
I bought, and the next size bigger... is about $450, almost 50% more.
That more than paid for the vacuum insulation panels.


BTW, my father-in-law, an HVAC engineer and inventor, rigged up his home
A/C to heat the swimming pool water with the waste heat. It worked great
for a number of years, but now that he's 84 and his war injuries have
caught up to him, he has trouble maintaining it. With the extra plumbing,
its possible to loose the pool water, and then be without both pool and
A/C.


Excellent idea, but by late summer I bet the pool was quite warm. This
would be a great system to use on a spring-fed pond!


Doug Dotson wrote:
I've gotten great service out of my spillover system. Cold plates in the
freezer only.
Thermostacally controlled vent into the fridge side. Large boxes. Probably 3
cuft
in the freezer and 12 cuft in the fridge.


Spillover systems can be very efficient if the access isn't terrible.
For many, to get into the freezer you go thru the fridge, and leave the
door open while you rummage around.

My experience with fridge/freezers in one box is that if you set them
cold enough to keep ice cream, they freeze the milk. Others may have
better design.

Most boat fridge installations commit at least one of the following
cardinal sins: air cooled unit with insufficient air flow, wiring sized
and/or connected improperly so unit sees low voltage, poor insulation,
leaky door. The owners usually gripe about the last tech to service it
and want the refrigerant loop recharged.

Fresh Breezes- Doug King


  #18   Report Post  
Doug Dotson
 
Posts: n/a
Default


"Jeff" wrote in message
...
Doug Dotson wrote:
I like this setup. As I've mentioned before, using one compressor for
both fridge and freezer can be a problem. The BD35 gives a lot of bang
for the buck.

I've gotten great service out of my spillover system. Cold plates in the
freezer only.
Thermostacally controlled vent into the fridge side. Large boxes.
Probably 3 cuft
in the freezer and 12 cuft in the fridge.


Then you really don't have a two box system.


It was two boxes last time I looked.

And, as with mine, you have no way to run the fridge only.


True, but I have no need to do such.

If you truly had two boxes with two compressors, as I assume DSK has,
then you have the option of shutting down the freezer to save energy, plus
you have a backup.


Sorry, a fridge isn't a good backp for a freezer and visa versa. But I truly
have 2 boxes. You can come over and count them if you are in doubt.

I have nothing against spillover systems, and your compressor system is
probably almost identical to mine. I'm just pointing out possibilities
that might work for different situations.

Of course.


  #19   Report Post  
Doug Dotson
 
Posts: n/a
Default


"DSK" wrote in message
...
"Jeff" wrote
So you chose air cooled. How come?


Smaller cheaper unit, plus my confidence in my ability to post-engineer a
seawater assisted cooling unit from either of the two already existing
seawater systems on board.

One of the little ironies is that in cold water, the air in the bilge may
be much cooler than on deck or in the engine room. I never bothered to
measure, but I wonder if that's also true in the tropics.


I'm sure it is. There would be at least a little cooling effect on air
flowing into the bilge and then up thru the condensor... and presumably,
thence overboard. It would help ventilate an area that prob'ly needs it,
too.


As for savings - the cost difference between the BD50 and BD35 is pretty
small - certainly much less than a through hull, pump, and condenser.
However, once you get larger its clear that water cooling has advantages.


Actually the difference in price between the two Waeco units... the one I
bought, and the next size bigger... is about $450, almost 50% more. That
more than paid for the vacuum insulation panels.


BTW, my father-in-law, an HVAC engineer and inventor, rigged up his home
A/C to heat the swimming pool water with the waste heat. It worked great
for a number of years, but now that he's 84 and his war injuries have
caught up to him, he has trouble maintaining it. With the extra
plumbing, its possible to loose the pool water, and then be without both
pool and A/C.


Excellent idea, but by late summer I bet the pool was quite warm. This
would be a great system to use on a spring-fed pond!


Doug Dotson wrote:
I've gotten great service out of my spillover system. Cold plates in the
freezer only.
Thermostacally controlled vent into the fridge side. Large boxes.
Probably 3 cuft
in the freezer and 12 cuft in the fridge.


Spillover systems can be very efficient if the access isn't terrible. For
many, to get into the freezer you go thru the fridge, and leave the door
open while you rummage around.


Never seen one like this. Terrible design IMHO. Door in in the counter
so not that much air escapes.


My experience with fridge/freezers in one box is that if you set them cold
enough to keep ice cream, they freeze the milk. Others may have better
design.


Never had this problem. Our freezer will freeze ice cream rock solid and
will
freeze 2 trays of ice cubes in 1/2 hour. Fridge side never gets below
freezing
due to the thermostatically controlled vent that lets the air from the
freezer
side to the fridge side

Most boat fridge installations commit at least one of the following
cardinal sins: air cooled unit with insufficient air flow, wiring sized
and/or connected improperly so unit sees low voltage, poor insulation,
leaky door. The owners usually gripe about the last tech to service it and
want the refrigerant loop recharged.


I agree!

Fresh Breezes- Doug King

Doug
s/v Callista


  #20   Report Post  
Evan Gatehouse
 
Posts: n/a
Default

DSK wrote:

Some may be interested in my current project, 98% complete at this
point: installing a freezer built into our dinette seat. After a LOT of
research and spreadsheeting all the numbers, I decided on a Waeco
(Adler-Barbour) CU-84 (based on the Danfoss BD-35) air cooled
refrigeration unit, with an exhaust to the outside. The box is insulated
on 5 sides with R-28 vacuum panels. I am currently finishing the lids, a
relatively demanding bit of fiberglassing that I don't recommend.
http://community.webshots.com/photo/...89712634CcPfiT
(next 7 pics)

Fresh Breezes- Doug King


I gotta ask - why the carbon fiber in a freezer?

Evan Gatehouse

Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Norwegian "sjekte" wooden boat advice requested markeike Boat Building 1 July 24th 05 08:19 PM
GPS Advice Tom General 7 January 20th 05 07:47 PM
Alternative Energy for Refrigeration Richard Kollmann Cruising 2 October 28th 04 02:14 AM
Save from $50 to $2000 on refrigeration icstallation and repairs Richard Kollmann Boat Building 0 August 23rd 04 03:54 PM
Sage restoration advice wanted (osmosis) Angus Gratton General 4 November 14th 03 06:04 PM


All times are GMT +1. The time now is 05:20 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 BoatBanter.com.
The comments are property of their posters.
 

About Us

"It's about Boats"

 

Copyright © 2017