Author Topic: Refridgeration  (Read 2303 times)

Jules Shockley

  • Sr. Member
  • ****
  • Posts: 153
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Dragon Lady
Refridgeration
« on: February 18, 2017, 08:31:19 AM »
Am replacing my old Crosby refer system with a dc unit. I installed 380 watts of solar so there should be sufficient power for a 7 cu ft system with good insulation. I was leaning away from a holding plate system such as cool blue but I have found a new unit at a good price. Holding plate vs evaporator. Any thoughts? Run time, power consumption, efficiency, reliability?
Jules, Dragon Lady

Soggy Paws

  • Moderator
  • Hero Member
  • *****
  • Posts: 523
    • View Profile
    • Cruising with Soggy Paws
  • Boat Type: CSY 44 WT
  • Boat Name: Soggy Paws
Re: Refridgeration
« Reply #1 on: February 18, 2017, 09:11:15 AM »
Jules,

I have spent a lot of time and money on refrigeration over the past 20 years.  I think we finally got it right a few years back when we switched from a Tecumseh compressor/holding plate system to the more modern Frigoboat Danfoss compressor/evaporator plate system.  Compared to the old holding plate systems, the new systems are so much better and aren't expensive--about $1500 US for a good system like ours.  I would never go back or use a holding plate system again.  See some of our notes at:

http://www.svsoggypaws.com/frigoboat_installation.htm
http://svsoggypaws.blogspot.com/search/label/Frigoboat

We are now on the new cat and have installed the same Frigoboat keel cooler system in our recently built 8 cu ft refrigerator box.  It is light weight, quiet, very energy efficient, holds temp within 2 degrees and highly recommended by not only me but also Steve Dashew and Nigel Calder.  It works the way a good refrig should.

 Dave
« Last Edit: February 18, 2017, 09:15:29 AM by Soggy Paws »
CSY 44 Walkthru #35, Soggy Paws
Soggy Paws the CSY has been SOLD
http://svsoggypaws.com/CSY/For_Sale.htm

Jules Shockley

  • Sr. Member
  • ****
  • Posts: 153
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Dragon Lady
Re: Refridgeration
« Reply #2 on: February 18, 2017, 10:32:12 AM »
Thanks Dave,
The negative I saw about evaporator plates was the constantly cycling on and off, I'm sure depending on insulation.
The negative about a holding plate was the ever changing temperature which contributed to much more condensation.
You've been there, done that on a lot of subjects, so your opinion is probably dead on. An evaporator with a spillover system for  about 7 cu ft. I plan to beef up the old boxes for at least 4 inches of additional insulation. Don't know where the compressor will go, maybe a space in the bottom of the boxes, glassed in. Thoughts?

Soggy Paws

  • Moderator
  • Hero Member
  • *****
  • Posts: 523
    • View Profile
    • Cruising with Soggy Paws
  • Boat Type: CSY 44 WT
  • Boat Name: Soggy Paws
Re: Refridgeration
« Reply #3 on: February 18, 2017, 08:56:27 PM »
Jules,

I'm not sure why someone would consider cycling on and off a negative.  Unless it is right in your ear you can't hear the compressor anyway.  A little muffin cooling fan makes more noise than the compressor! By constantly cycling like your home refrig, it can keep the box temp within about 2 degrees.  It does not harm the compressor.  A big reciprocating compressor could not do that. 

You are right about the holding plate negative.  They have a big box temp swing.  Mine saw about 15 degrees while holding over about 8 hours.  And that was with proper R20 insulation for the refrig and R30 for the freezer.  There are many other negatives for holding plates vs evaporator plates too so research carefully.  Just remember that not everything you hear or read is true.  The competition among refrig salesmen is intense.

Once you figure out your box sizes and insulation R value, Frigoboat has an excellent section on their website that will help you size an efficient compressor and evaporator plate.  A little bigger than calculated will be better as it will allow you to run the compressor at its lowest speed giving up to 30% more amp efficient system compared to running the compressor at high speed.  My new Danfoss based system used exactly the same amp hours the old holding plate system did and that was what the Frigoboat literature said it would use.  With two separate BD50 systems running at low speed cooling an 11 cuft side loading refrig and a 3 cu ft top loading freezer we used about 80 ahrs on a daily basis in the tropics.  Just make sure your insulation is right and door gaskets are tight.

If you want better efficiency over an air or water cooled system consider the keel cooler system which is what we are using.  The big benefit is saving about 15 amps a day over the others.  This system has no big cooling fan or water pump run heat exchanger.

Dave


Dave

Dave
CSY 44 Walkthru #35, Soggy Paws
Soggy Paws the CSY has been SOLD
http://svsoggypaws.com/CSY/For_Sale.htm

Mike Zofchak

  • Sr. Member
  • ****
  • Posts: 138
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Buckeye Queen
Re: Refridgeration
« Reply #4 on: February 20, 2017, 08:48:46 AM »
Hello Jules,

I am investigating refer systems right now. I plan on going with an evaporator system over holding plate as well, just not sure which manufacturer. I like the idea of the Keel Cooler just have not made a decision yet. Hate the idea of another two (2) holes in the boat…

I removed my old box and insulation. The old insulation was garbage!! Rebuilt the refer and freezer with new insulation and added steps/shelves to the back were you would normally have the curve of the hull. I would be happy to discuss my new rebuild as I think it is going to work great.
Capt. Mike Zofchak
Land Locked S/V Buckeye Queen

Jules Shockley

  • Sr. Member
  • ****
  • Posts: 153
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Dragon Lady
Re: Refridgeration
« Reply #5 on: February 21, 2017, 07:22:34 AM »
Mike,
I have decided against a holding plate system which is becoming old technology. Fridgoboat or Isotherm have systems that can be converted to keel cooling at a later haulout, which is a much more efficient system. I would like to see your pictures of the rebuild as I am a week from starting the same project. Would be good to know what to expect.
Jules

Mike Zofchak

  • Sr. Member
  • ****
  • Posts: 138
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Buckeye Queen
Re: Refridgeration
« Reply #6 on: February 21, 2017, 10:00:07 AM »
Jules,

I sent you a PM.

Thanks,
Capt. Mike Zofchak
Land Locked S/V Buckeye Queen

Soggy Paws

  • Moderator
  • Hero Member
  • *****
  • Posts: 523
    • View Profile
    • Cruising with Soggy Paws
  • Boat Type: CSY 44 WT
  • Boat Name: Soggy Paws
Re: Refridgeration
« Reply #7 on: February 21, 2017, 07:28:25 PM »
Jules,

A couple of other quick notes:

It would be worth your time to read Nigel Calder's 3 edition Mech and Elec Manual section on refrigeration.  It will give you great detail and help on making decisions on equipment and installation.  Look especially at his testing of various insulation materials.  I took his advice and used extruded polystyrene (blue or pink board) on my freezer on the CSY and now refrig on the cat.  Hard to beat R value of 6.5 and no water absorption.

Don't stress too much about drilling the 1.5 inch keel cooler hole in your hull.  The keel cooler you install is stronger than any hull, has no valve to leak, and if done carefully you will have no problems and a big amp benefit.

If you are considering the Isotherm equivalent, it works, but is less efficient because it is in enclosed space and needs some boat motion to get rid of the heat.  See Calder and others on this. 

We found that the Frigoboat keel cooler can also work if on low speed while on the hard if you drip some water on it over a rag.  We have used that method for months on the hard here in the Philippines with no problem.

Dave
CSY 44 Walkthru #35, Soggy Paws
Soggy Paws the CSY has been SOLD
http://svsoggypaws.com/CSY/For_Sale.htm

Jules Shockley

  • Sr. Member
  • ****
  • Posts: 153
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Dragon Lady
Re: Refridgeration
« Reply #8 on: February 22, 2017, 06:24:59 AM »
Thanks Mike. I sent you a PM.
Jules

Jules Shockley

  • Sr. Member
  • ****
  • Posts: 153
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Dragon Lady
Re: Refridgeration
« Reply #9 on: February 22, 2017, 06:31:49 AM »
Dave,
No problem with the extra hole. In fact I have an unused thru hull that I can convert. It will be a while before I haul again and I noticed that the air cooled model could be converted at a later date. Does sound like the way to go. Where do you recommend I place the compressor as I intend to convert and use the old boxes.
Jules

Soggy Paws

  • Moderator
  • Hero Member
  • *****
  • Posts: 523
    • View Profile
    • Cruising with Soggy Paws
  • Boat Type: CSY 44 WT
  • Boat Name: Soggy Paws
Re: Refridgeration
« Reply #10 on: February 22, 2017, 06:49:54 PM »
Jules,

What boat do you have?
 
The keel cooler needs to be within 5' of the compressor and you want the compressor in a well ventilated space where you can have a small muffin fan run across the top of the compressor.  I mounted a muffin fan on top of the electronic control unit next to the compressor with velcro.  From there it blows across the top of the compressor and removes excess compressor heat.

On the 44 walkthru I mounted the compressor for the refrig in the aft cabin under the small seat in the fwd stbd corner of the room.  It already has a wooden vent screen.

I built the freezer under the main cabin table so it may be different from yours.

Dave
CSY 44 Walkthru #35, Soggy Paws
Soggy Paws the CSY has been SOLD
http://svsoggypaws.com/CSY/For_Sale.htm

Jules Shockley

  • Sr. Member
  • ****
  • Posts: 153
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Dragon Lady
Re: Refridgeration
« Reply #11 on: February 23, 2017, 10:50:26 AM »
Dave,
I have a walkover and I've thought of placing the compressor under the bottom of the current fridge after shortening the boxes to around 7 cu. ft. Of course a recirc fan to draw in cooling air would be a must. The other place would be under the aft end of the stbd settee. Are there other owners who have done this or have ideas?
Jules

Soggy Paws

  • Moderator
  • Hero Member
  • *****
  • Posts: 523
    • View Profile
    • Cruising with Soggy Paws
  • Boat Type: CSY 44 WT
  • Boat Name: Soggy Paws
Re: Refridgeration
« Reply #12 on: February 25, 2017, 07:33:35 AM »
Jules.
We find that for long term overseas cruising 3-4 cuft of freezer and 8-11 cuft of refrig are about right.  We like fresh veggies, cold drinks and a place to keep fresh meat/fish long term.  We much prefer a side loading refrig for its convenience and quick food extraction.  You can't change that.
I am not familiar enough with the 44WO to know where is best for the compressor.  Just don't put it in the engine room and make sure you have good ventilation.

Dave
CSY 44 Walkthru #35, Soggy Paws
Soggy Paws the CSY has been SOLD
http://svsoggypaws.com/CSY/For_Sale.htm

Mike Zofchak

  • Sr. Member
  • ****
  • Posts: 138
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Buckeye Queen
Re: Refridgeration
« Reply #13 on: February 25, 2017, 09:23:42 AM »
Jules,

I did not receive your e-mail.
Capt. Mike Zofchak
Land Locked S/V Buckeye Queen

Jules Shockley

  • Sr. Member
  • ****
  • Posts: 153
    • View Profile
  • Boat Type: CSY 44 W/O
  • Boat Name: Dragon Lady
Re: Refridgeration
« Reply #14 on: February 26, 2017, 11:35:13 AM »
Mike, I sent a text to your phone.