Input needed: New fridge system for our Dufour 35

[Terra Nova]

Originally Posted by Rorzech

...This is easy for me to do and I could tell anyone (who's handy) how to do it...

Oh boy...

[David B]

We are also in the process of wanting to extend our cold-storage.
For us, the Dometic CD-30 works the best as far as fitting it into the boat without any real cabinetry changes. That gives us an extra 30 litres of capacity, and being a drawer fridge, uses very little area.
We are cutting it into the timber face on one of the saloon seats, so the whole unit will just be totally out of the way.

Might work for you also.

[OzePete]

Originally Posted by Rorzech

My desire is to have a 2 cu.ft. freezer that can achieve -27 F (I found one)and increase the foam from 2" to 4" and reroute the condenser into the bilge or on deck. The 120V AC compressor uses 40 watts and will run 20% duty cycle.It will be so cold and insulated that it could stay frozen for a couple of days at least if I lost power for some reason,and if I don't go into it a lot. For a fridge I would just use a medium cooler with a couple of frozen water bottles in it. and I could put it anywhere on the boat I feel like, even in the cockpit. Meanwhile making all the Ice I want in the freezer for it. This is easy for me to do and I could tell anyone (who's handy) how to do it.You just need to borrow couple expensive tools (good vacuum pump). Tubes can be put together with unions and flare nuts (so you don't burn down your boat).Evaporators with cap & suction lines can be purchased cheap,the bigger the better. Feel like a challenge ?

Mate, it's my desire to win the big lottery, but that's not going to happen either!!! I have put your proposed cabinet's details through our heat load / consumption estimator and your expectations are not going to be realised. For a start -27F is not going to happen so lets just work with -5F. To maintain -5F withg normal usage in an extreme environment your 55 litre (2CF) cabinet has an hourly heat load of up to 20.6 watts per hour and with a 56% duty cycle it will consume 1.46 amps/ hour. This doesn't account for the loss of energy inverting 12VDC to 110VAC or the fact that AC compressors have a very short life if used in mobile situations. You may wish to reconsider or have someone in the industry assist you.
Cheers,
OzePete Ozefridge

[txg]

I was thinking about the CD-30 as well because we could install it easily in a space where we do have one of our two (french boat...) wine racks. But 30L is still a little bit on the small side and if i start to spend money i want to do it right.

To take frozen bottles out of the freezer and put them in a passive fridge sounds not like a usable long-term solution for me. I want something hassle-free.

@ColdehMarine:

Thank you very much for your continued professional input even if i can't afford buying anything from you. Regarding space for insulation on the factory icebox: Thats hard to say. I would approximate something like this:

-On the bottom, there is probably space for about 5-6 inches of insulation except for the portside bottom corner, there it's only about one inch to the hull.
-Its also about 5-6 inches to the stern end, but only 2-3 on the bow side (and there it has to be spray foam that has to be inserted through small holes from the saloon).
-On the starboard side it is at least 4-5 inches, on the portside it starts at about 1-2 inches on the bottom and then goes up to maybe 4-5.

Maybe the easiest solution to check for the possibility of a spillover system would be to install a bd35 system with a large flat plate on the portside wall, put it to -6°C and then insert some styrofoam to separate the two compartments just to check out if the compressor is powerful enough and if we can live with the Ah consumption. And if it doesn't work as expected we can simply use the whole space as a fridge.

[Typhoon]

Originally Posted by txg

I was thinking about the CD-30 as well because we could install it easily in a space where we do have one of our two (french boat...) wine racks. But 30L is still a little bit on the small side and if i start to spend money i want to do it right.

To take frozen bottles out of the freezer and put them in a passive fridge sounds not like a usable long-term solution for me. I want something hassle-free.

@ColdehMarine:

Thank you very much for your continued professional input even if i can't afford buying anything from you. Regarding space for insulation on the factory icebox: Thats hard to say. I would approximate something like this:

-On the bottom, there is probably space for about 5-6 inches of insulation except for the portside bottom corner, there it's only about one inch to the hull.
-Its also about 5-6 inches to the stern end, but only 2-3 on the bow side (and there it has to be spray foam that has to be inserted through small holes from the saloon).
-On the starboard side it is at least 4-5 inches, on the portside it starts at about 1-2 inches on the bottom and then goes up to maybe 4-5.

Maybe the easiest solution to check for the possibility of a spillover system would be to install a bd35 system with a large flat plate on the portside wall, put it to -6°C and then insert some styrofoam to separate the two compartments just to check out if the compressor is powerful enough and if we can live with the Ah consumption. And if it doesn't work as expected we can simply use the whole space as a fridge.

Not to worry , all advice is given for free with no obligation to buy any thing from us . I just like to help fellow sailors navigate a bit of a mine field known as marine refrigeration.

Seems like you will have lots of insulation, how large is the area % wise of the 1 inch space on the port side bottom, as this will be your freezer section.

Also the single part foam may not fully cure and expand in a large void , this product needs lots of air to cure properly and may stay partially cured , thereby having no insulation value . I would use two part pour in place foam , the 2LB kind and pour it in, in layers , if you pour it in all at once you will damage the enclosure as it expands , it can create a lot of pressure. This will fully cure and give you high R value in that space .

Also you have to order the thermostat from your vendor for a freezer or a fridge , they are different , so maybe just get them both if you decide to stick with just a fridge.

Also you can build a system that will control fridge temperatures with just a simple fan and electronic thermostat that you can set the temperature in your fridge with . I find active spillover systems to have a more consistent temperature in the fridge side then any passive system .

Regards John.

[txg]

Originally Posted by ColdEh Marine

Seems like you will have lots of insulation, how large is the area % wise of the 1 inch space on the port side bottom, as this will be your freezer section.

Its not much. Imagine the hull of the boat that is quite round nearby the waterline and then the corner where side and bottom wall of the icebox join with a 90deg angle. between the corner and the hull there it is only about 1 inch. But if this will prove to be problematic i would simply add 2 more inches of insulation in the freezer inside, its not a big deal if we have a little less space there.

Today i went for a long walk to think this through again and here's what i came up with:

We will buy this isotherm kit with a large flat plate and install it on the boat when we are back in Grenada in january:
Isotherm GE 150 Compact Air Cooled Refrigeration Component System

For temperature control for the freezer compressor and the fridge spillover fan as well we will buy two of those, thanks to funjohnson for the idea:
https://www.amazon.de/Temperature-Co...rb_top?ie=UTF8
This also makes it easy to check temperatures.

After installing the compressor system we will insulate the whole box. As we have to source the insulation in Grenada it will probably consist of standard PU plates, i've already seen them in a shop nearby our boatyard.

We will then try to run the whole box as a freezer to find out if the compressor is powerful enough for our plans. If this is the case, we will build a spillover system like ozefridge sells:
http://www.ozefridge.com.au/wp-conte.../seesketch.jpg
Have a look at the duct, actually there is no air exchanged between fridge and freezer but the aluminium duct works as a heat exchanger. I think this is a brilliant idea to keep frosting in the freezer down. My idea is to suck cold air in at the bottom of the fridge and then use the fan on the top to push it out. This should make a very even temperature in the fridge and also cool down drinks very fast.

Then we will run the whole system and check how the distribution between freezer and fridge is working. Especially i want to make sure that nothing defrosts in the freezer when warm drinks are put in the fridge. Maybe we have to connect the compressor to the fridge thermostat as well so it is running whenever the spillover fan is started.

By making the interior divider removable we can take it out and use the whole box as a fridge whenever we want to. Also, when we're on a longer crossing and are starting to run out of stuff that needs to be cooled we can put in a styrofoam divider and only use the smaller freezer as a fridge to keep drinks cold when we are running low on energy.

Does that sound like a decent plan?

[Typhoon]

Ok , your plan sounds good .
Just a few notes . Do not control the evaporator plate with a box temperature thermostat . These systems are designed to cycle . The system will run out of balance especially as a deep freeze . At best it will use more energy , at worst it could damage your compressor , use the thermostat that is supplied with the system ! If you do not it will invalidate your warranty. There is a reason for this but it is very complicated . Make sure you order the thermostat for a freezer and attach it to the plate as they recommend . If you are going to change it to a fridge you will need a different thermostat for that temperature range.

Next thing , yes put the two inches of insulation in that thin space . The more the better in the freezer side .

Draw the cold air into the top of the fridge from the freezer and out the bottom .

The duct is a great idea if you have the space .

Again I have to say , only control the freezer spillover fan with the electronic thermostat . This will be the controller for the fridge temperature .

Regards John

[Terra Nova]

Originally Posted by txg

...between the corner and the hull there it is only about 1 inch. But if this will prove to be problematic i would simply add 2 more inches of insulation in the freezer inside, its not a big deal if we have a little less space there...

Better do some some reading on marine refrigeration systems before going any further. At that point you would introduce an angled facet in the liner, instead of a sharp, 90* corner. Shoot for 4" minimum insulation.

[Rorzech]

Yes , I like your plan a lot. Just keep in mind that vapour leaks rob your energy so vapour barrier is always on the warm side. You want it as air tight as possible. As far as thermostats go it's better to use a VC-1 attached to the cold plate in the freezer and just use an airway or partly insulated wall between fridge and freezer to maintain a fridge temperature. You want to keep your freezer really cold like 5+F or lower or your food will grow cell damaging crystals making your food taste funny after a couple week Cheers

[Badsanta]

I like the oz frig spillover as it keeps moisture out of the freezer. I plan too do the same but will ad a lid to the freezer

[OzePete]

Originally Posted by Badsanta

I like the oz frig spillover as it keeps moisture out of the freezer. I plan too do the same but will ad a lid to the freezer

Hi Badsanta, If you use a metal heat exchanger located on the freezer side of the divider, you might like to consider;
1: Allow for two air holes say 75mm diameter in the dividing wall, as high and as far apart as possible. (Same level)
2: Have the exchanger cover as much of the wall as possible.
3: Fit a baffle from the top centre downwards to 1/3 from the bottom to ensure air has to travel down then up to best allow heat transfer.
4: Use an 80mm thermostat controlled fan located on the fridge side to push air through one of the 75mm holes and into the exchanger
5: Make the exchanger say with a 15mm air traffic area. (Thickness) The dividing wall can for one side of the exchanger but needs to be sealed.
6: If possible make the exchanger so it can be removed for de-icing if it gets chocked. This can happen in extreme humidity areas or when lid seals are defective. In normal use the exchager will remain ice free.


Cheers, OzePete Ozefridge | 12 Volt Refrigeration Systems

[txg]

We finally got to doing this project.



In the end we bought an Isotherm kit with BD50 and large O-Evaporator.

Insulated the box with 2" PU-Plates and 2-part foam, thickness is between 2 and 7 inch depending on the available space.


I hooked it all up yesterday and while the compressor starts fine, the Evaporator doesn't get cold. The compressor pulls about 4.5 amps and starts to get quite warm after a while, with nothing else happening. The line to the Evaporator stays warm as well. What i noticed is that after stopping the compressor, the thinner connector on the compressor starts to get cold for a while.



Very strange, maybe i did something wrong when connecting compressor and evaporator, though it looks like an easy task. Just screwed it on and tightened it down quite hard.



Looks like we need to find a refrigeration technician tomorrow, currently located in Le Marin, Martinique.

[Richard Kollmann]

Originally Posted by txg

We finally got to doing this project.



In the end we bought an Isotherm kit with BD50 and large O-Evaporator.

Insulated the box with 2" PU-Plates and 2-part foam, thickness is between 2 and 7 inch depending on the available space.


I hooked it all up yesterday and while the compressor starts fine, the Evaporator doesn't get cold. The compressor pulls about 4.5 amps and starts to get quite warm after a while, with nothing else happening. The line to the Evaporator stays warm as well. What i noticed is that after stopping the compressor, the thinner connector on the compressor starts to get cold for a while.



Very strange, maybe i did something wrong when connecting compressor and evaporator, though it looks like an easy task. Just screwed it on and tightened it down quite hard.



Looks like we need to find a refrigeration technician tomorrow, currently located in Le Marin, Martinique.

The Isotherm Model : IS-SGC00005AA was a good choice it provides both a refrigeration and true freezer without a Mickey Mouse spillover gadgets.

These Aero equip self sealing line connectors can leak refrigerant when not sealed in shipment with proper caps. Before spending too much time and money where you are I would recommend adding 134a pure refrigerant bringing amperage draw up to 6.5 amps after 20 minutes. Be sure whoever adds refrigerant purges the servicing equipment first. This should be correct refrigerant charge for local temperatures there but tomorrow if frost extends on line outside refrigerated area email me. Be sure to test the line connection with soap and water.

My books have always recommended to boaters that leak detection by using a 50/50% mixture of dish washing soap and water is the best way for them to find refrigeration leaks. The correct procedure is to use the tips of a one inch brush to beat the soap mixture into a suspected area until it resembles shaving cream then watch area for two to three minutes to see if bubbles begin to form. Very small leaks in suction side of system can only be located with refrigerator box warm and system off due to low pressure in this area when system is cold or running.

[OzePete]

[QUOTE=Richard Kollmann;2644346]The Isotherm Model : IS-SGC00005AA was a good choice it provides both a refrigeration and true freezer without a Mickey Mouse spillover gadgets. Would be IF it worked!

These Aero equip self sealing line connectors can leak refrigerant when not sealed in shipment with proper caps. Before spending too much time and money where you are I would recommend adding 134a pure refrigerant bringing amperage draw up to 6.5 amps after 20 minutes. This 'advice' I disagree with. The system is new so the first thing would be to contact the supplier seeking advice on how THEY wish to sort this problem.

Next, any of these micro refrigeration systems should NEVER simply have refrigerant gas added, although it may be necessary to add some intially for lead detection, followed by evacuation after the leak is identified and repaired. The ONLY time a system needs re-gassing is if it has lost gas via a leak or the system has been opened to replace a component. Either way the system will most likely be contaminated with air / moisture and must be properly evacuated (hopefully with a new filter dryer fitted) and then re charged with pure refrigeration grade refrigerant. Simply adding gas without evacuation, specially R134a, to a system is very bad advise!

Be sure whoever adds refrigerant purges the servicing equipment first. This should be correct refrigerant charge for local temperatures there but tomorrow if frost extends on line outside refrigerated area email me. Be sure to test the line connection with soap and water.

My books have always recommended to boaters that leak detection by using a 50/50% mixture of dish washing soap and water is the best way for them to find refrigeration leaks. The correct procedure is to use the tips of a one inch brush to beat the soap mixture into a suspected area until it resembles shaving cream then watch area for two to three minutes to see if bubbles begin to form. Very small leaks in suction side of system can only be located with refrigerator box warm and system off due to low pressure in this area when system is cold or running. Good advice for leak detection. We and other fridgies use his method as electronic detectors are not real good with R134a [/QUOTE)

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[Richard Kollmann]

Pete if you expect to sell boat refrigeration other than in Australia close to your shop you need to address and solve problems in the best way possible. Your websites solution to return unit to factory will not work on an island 12,000 miles away with only unskilled people. Generally in these remote areas of the world boaters have to rely on other boaters for servicing equipment and pure refrigerant. I have told you before bad advice to a boater on other than your own refrigeration design will lose you future sales.