Who provides the best 12 volt refrigeration systems?

[SV THIRD DAY]

I was asked how MMGW and its' increased temperature in the tropics (where an awful lot of us want to cruise) would affect a cruisers refrigerator choice? The solution or course is.....

[OzePete]

Agree with Rich's comment above. We also offer two phase change brews for our eutectic plates, one for freezers at approx -20C PC the other fridge at approx -5C PC. The freezer brew can be diluted if a warmer freezer temperature is required but usually these two temperature ranges cover all applications provided the eutectic tank capacity is engineered to suit the cabinet / application.
Using a wide Hysteresis (HYS = Difference in number of degree between cut out and cut in.) and controlling the eutectic mass temperature, the cabinet temperature can be adjusted without loosing the phase change benefits. We have thousands of systems floating around doing exactly that.

Having the heat load of your specific cabinet calculated is essential for correct equipment to be chosen and desired results achieved. You might say why when I can just buy one off the shelf?

Like buying a new suit, one size does not fit all and with a new refrigeration system there are even more issues to consider.

A correctly engineered eutectic system will only need *two cycles per day in most conditions. The size of eutectic plate(s) and the refrigeration system's capacity, needs to suit the task in the worst conditions likely because that is when you will need it most.

The only way to be sure of selecting the correct equipment is to have the heat load properly calculated, guess work or what Fred did 20 years ago won't do!

We have a range of four plates from 33 x 29mm to 650 x 540mm each available in 25, 40 and 60mm thicknesses so that the eutectic plate can correctly match the load and actually operate as a Phase Change system. (*ECO2 will cause one of those cycles will occur automatically when power is abundant effectively halving battery demand..)



Cheers OzePete

[Singularity]

Originally Posted by SV THIRD DAY

I was asked how MMGW and its' increased temperature in the tropics (where an awful lot of us want to cruise) would affect a cruisers refrigerator choice? The solution or course is.....

Step #1: LiFePO4 (LFP)

Quote:

LiFePO4 batteries are a game changer for sure.
I installed my 400AH bank over two years ago now and would never go back to lead, so on that we are in Freezer Insulation of R-40 per inch or bettercomplete agreement.
http://www.cruisersforum.com/forums/...-171845-7.html

Step #2: Choose the best refrigeration unit for the tropics
Option A: $2500 DC marine refer unit
Option B: $400 AC unit from a home supply store

$2100 can be invested in solar, fuel for charging, spare AC units, etc.

[SV THIRD DAY]

I'm on year 4 of a LiFePO4 bank....but you STILL have to replace what you use on a dialy basis. A LiFePO4 bank doesn't created daily power...so the Daily Amps In/Amps Out game is still in play you either add more solar or have a more efficiency refrigeration system. The Battery is just the middle man in the equation.

Do you know how many Cruisers I see in Mexico with LiFePO4 banks and a Home refrigerator....ah....I'll let you know when I find one.

Why...because it's the whole package, not just the battery bank, not just the amount of solar, not just the type of refrigerator system. A three legged stool still tips to the weakest link. A guy doing lithimum isn't the guy looking to save a few bucks on Home Depot refrigerator...sounds good in a Chat room, but it just isn't reality.

[newhaul]

Originally Posted by Singularity

Step #1: LiFePO4 (LFP)

Quote:

LiFePO4 batteries are a game changer for sure.
I installed my 400AH bank over two years ago now and would never go back to lead, so on that we are in Freezer Insulation of R-40 per inch or bettercomplete agreement.
http://www.cruisersforum.com/forums/...-171845-7.html

Step #2: Choose the best refrigeration unit for the tropics
Option A: $2500 DC marine refer unit
Option B: $400 AC unit from a home supply store

$2100 can be invested in solar, fuel for charging, spare AC units, etc.

show me an AC unit from homer depot that will do what I want with my unorthodox design and I will buy it and give you a c note for bird dogging it for me.

[OzePete]

Originally Posted by john61ct

How about the potable water antifreeze?

Source links?

And if converting say a freezer box to a fridge, whose holding plates allow the user to swap out the solution themselves?

Should the phase change point really be right at the desired setpoint, center of the hysteresis range, or at the top, or just below?

Two issues, firstly the phase change medium used should freeze 5C to 8C below the required cabinet temperature as others suggest.

Secondly to ensure that phase change actually occurs and the efficiency benefits are achieved, the refrigeration system must run until the mass is frozen solid then stay off until it thaws. Only then do you have a eutectic system and the only way to achieve this is to have the refrigeration systems controller reading the phase change materials mass, not cabinet temperature. Done correctly the cabinet temperature will remain quite constant in all situations.

Back to your question John... if the eutectic plate is properly controlled then SET needs to be say 4 or 5C lower than the phase change temperature and with an 8C hysteresis. So for a fridge PH would be say -5C so SET (Unit 'cut off) would be -10C and with an 8C hysteresis the 'cut in would be -2C ensuring that PH actually occurred with every cycle.

BTW, all so-called eutectic mixes fortunately will phase change over a range of a few degree C., not at a given temperature instantly. This range increases when a lower phase change mix is used. This is also why reading/ controlling the phase change medium's temperature and using a relatively wide hysteresis is essential.

Cheers OzePete

[Singularity]

Originally Posted by newhaul

show me an AC unit from homer depot that will do what I want with my unorthodox design and I will buy it and give you a c note for bird dogging it for me.

I don't need the $ (but would shake you down in the field for a liquid if the opportunity arose and was earned). You mentioned before about a spillover of 5 feet total? Of course you can google around, but Sailorchick (a bonafide engineer in South North America; she's a lady and I would never ask her battery type) wrote that she uses the $250 Edgestar 3.1CF (see link for thread and discussion). What specific size were you needing? AH limit? Horizontal/top open?

---

I think I'm going to bang out an infographic in to more make clear my understanding of things, and why DC refrigeration should not be assumed to be the correct component of a modern refrigeration system...may be a day or two. LFP is a game changer, and this is part of the game that it changed.

[newhaul]

Originally Posted by Singularity

I don't need the $ (but would shake you down in the field for a liquid if the opportunity arose and was earned). You mentioned before about a spillover of 5 feet total? Of course you can google around, but Sailorchick (a bonafide engineer in South North America; she's a lady and I would never ask her battery type) wrote that she uses the $250 Edgestar 3.1CF (see link for thread and discussion). What specific size were you needing? AH limit? Horizontal/top open?

---

I think I'm going to bang out an infographic in to more make clear my understanding of things, and why DC refrigeration should not be assumed to be the correct component of a modern refrigeration system...may be a day or two. LFP is a game changer, and this is part of the game that it changed.

ok here ya go its a top load spill over system 3 cf fridge and 1.5cf freezer but here is where it gets interesting my divider is going to be movable to go all the way from .5 cf freezer and the rest fridge to 4cf freezer and .5cf fridge. Hence the oversize holding plate system . And r40 on one side and r 48 on the rest with r40 in the lid as well with Cryogel. All around. Converting the icebox In a 1963 columbia defender so space is premium.
As far as SC she is using gc2 Fla batteries.
In the picture you can see the outline for the lid and the lifting ring
The ice box is under the little 12 volt coffee pot.

[daletournier]

Originally Posted by Singularity

A question, for the sake of discussion.

Assuming 40,000nm ago you needed a refrigeration system installed. Assume you had a cold box, but it probably at minimum needed a little insulation, or maybe a complete rebuild (seriously, only a day or two project that will take a week for box work). Also 40,000nm ago assume that you had a 400ah 12 lead or AGM battery bank, maybe a cheap pure sine inverter on board, maybe not.

So, if 40,000nm miles ago instead of having a 12v marine refrigeration system installed (which you did), the question I have is: If you could have had a 400ah LFP bank installed with a commercial off the shelf (COTS) 110-240v AC refer for the same price as the 12v marine refer, would you still have kept your lead/AGM batteries, still gone with the 12v marine refer system? You would have been happy to forego the utility that the LFP could provide in favor of the DC refer reliability given the other options?

In fact I planned on a 12v system, but after I got the LFP, it just doesn't make sense to plop down $1500-$3000+ for a DC system when I can use $200-$400 terrestrial COTS 110-240v refer units. If worried about reliability, I can buy 2-3 extra AC voltage refers for <$1,000, stuff them with boat spares, then seal and stack them in the lazarette until the unit(s) in the cabin fail after 2weeks or 9 years, whichever comes first.

Just my thinking.

It depends.

It depends on the type of boat, where do I fit the ac domestic fridge? Without alterations this wouldnt work on my boat. Yes, if I could fit it well and it looked OK.

It depends on what type of cruising I was intending to do. For me personally, Lifepo aren't quite bulletproof enough for out of the way off the grid cruising, at least for the average cruiser (just my opinion). I also don't see enough value above what I already receive from my T105's to justify the expense of quality LiFepo4's. A large bank of 6v lead acid batteries IMO are almost bullet proof, assuming basic maintenance knowledge (which surprisingly many lack). I don't believe the life cycle claims have been proven in the real world yet. Once these systems are refined and past the early adopter stage and are proven to be very durable long term then I'm there. I've had solar regs and Balmar smart reg fail in the past which has potential consequences using LiFepo4 management systems that are a no issue with T105's.

A Marine refrigerator is generally a one off cost most of the time. They are reliable and efficient if incorporated as part of well thought out system.

[Singularity]

Originally Posted by newhaul

ok here ya go its a top load spill over system 3 cf fridge and 1.5cf freezer but here is where it gets interesting my divider is going to be movable to go all the way from .5 cf freezer and the rest fridge to 4cf freezer and .5cf fridge. Hence the oversize holding plate system . And r40 on one side and r 48 on the rest with r40 in the lid as well with Cryogel. All around. Converting the icebox In a 1963 columbia defender so space is premium.
As far as SC she is using gc2 Fla batteries.
In the picture you can see the outline for the lid and the lifting ring
The ice box is under the little 12 volt coffee pot.

I would look for a chest freezer, like the one below. I personally would try to get two separate 2.5cf freezers if I was in your situation. One 2.5cf unit would be "freezer forever." The second 2.5cf unit freezer would be used as a refrigerator by using an external voltage controller (pictured below). Using these freezers as refrigerators is widely done by folks living off-grid, using them to hold beer "kegorators" etc. All different sizes are available so you can mix and match, but a matching pair for redundancy (good or bad) is preferred by me, even if I have to make other compromises.

Without doubt you can hack the freezer to your liking (e.g. add insulation, increase the size of the box (which obviously effects run time, efficiency, etc, but maybe for a dedicated refer, it'd be perfect). Probably can devise a way to split the external-temp controlled freezer, I don't know. But the second refer can immediately be a freezer simply by letting it run on it's own thermostat.

[newhaul]

Originally Posted by Singularity

I would look for a chest freezer, like the one below. I personally would try to get two separate 2.5cf freezers if I was in your situation. One 2.5cf unit would be "freezer forever." The second 2.5cf unit freezer would be used as a refrigerator by using an external voltage controller (pictured below). Using these freezers as refrigerators is widely done by folks living off-grid, using them to hold beer "kegorators" etc. All different sizes are available so you can mix and match, but a matching pair for redundancy (good or bad) is preferred by me, even if I have to make other compromises.

Without doubt you can hack the freezer to your liking (e.g. add insulation, increase the size of the box (which obviously effects run time, efficiency, etc, but maybe for a dedicated refer, it'd be perfect). Probably can devise a way to split the external-temp controlled freezer, I don't know. But the second refer can immediately be a freezer simply by letting it run on it's own thermostat.

won't fit on my boat in to small . I'm only 29 feet long .
I'm using Cryogel ( its expensive) due to only being able to put 60mm of insulation over the majority of the existing box to get necessary r values.
My ice box as it exists is approx 14 inches wide 26 inches deep and about 28 inches long. ( not at boat so I'm guesstimating on length. So about 4.75 cf total ( some beveling of bottom due to hull shape.) will have extracts and pictures next week when I start the insulating project.

Edit I will also loose about .75 cf for the holding plate and the freezer fridge divider.

[sailor1026]

This has been a very educational thread. Missing is a discussion of refrigerants.

R134A has a high Global Warming Potential and newer refrigerants are less (R449A or R442A). There is also some talk of banning R314A and some of the older 400 series refrigerants (R404A and R410A).

[SV THIRD DAY]

Originally Posted by sailor1026

This has been a very educational thread. Missing is a discussion of refrigerants.

R134A has a high Global Warming Potential and newer refrigerants are less (R449A or R442A). There is also some talk of banning R314A and some of the older 400 series refrigerants (R404A and R410A).

R134a will be phased out in the future...new refrigerants that will be direct replacements are already out there....so don't panic yet.

[OzePete]

Originally Posted by sailor1026

This has been a very educational thread. Missing is a discussion of refrigerants.

R134A has a high Global Warming Potential and newer refrigerants are less (R449A or R442A). There is also some talk of banning R314A and some of the older 400 series refrigerants (R404A and R410A).

In 1961 when I started in the refrigeration industry, R12 was relatively new. The 'wise old guys' were very opposed to R12 advising this then young lad to stick with the Methyl Chloride, Sulphur and Ammonia systems!! What horrible gases they were and thankfully R12 become the dominant refrigerant.

We went through decades of bliss where this very efficient refrigerant along with R22 were used in all domestic and small commercial systems. A situation that provided efficient performance as well as efficiency in having equipment serviced. Two refrigerants covered all, now there are dozens of different brews of varying suitability, efficiency, flammability, oil compatibilty etc

I can recall R12 costing us 58 Cents a kilo trade. R134a went to over $62.00 a kilo here in Oz when the 'carbon tax' and other fees were applied, now that the carbon tax is gone it's just below $20.00. The Montreal convention saw a rush to ban these refrigerants based on the 'discovery of a hole in the ozone layer' (Later to be revealed that the hole was always there and expands/ contracts annually!!!)

If R12 was really causing environmental problems, I believe there could have been better ways of dealing with it than imposing the huge costs to consumers and the environment that the proliferation of far more expensive, less efficient refrigerants has caused.

As an old guy with decades in the refrigeration industry (and a bit sceptical!), in balance I believe that the costs to consumers and the environment have increased because of the way the refrigerant issue has been handled, when all aspects are considered. I think it has more to do with 'the bottom line' than the environment! And like Rich said an R134a replacement is on it's way, more $s to be made!

Cheers OzePete

[Richard Kollmann]

Secret to designing boat refrigeration for new Eco Technology refrigerants is in the design of the condenser unit and preventing refrigeration system leaks. Most of the R134a condensing units in icebox conversions sold today when installed correctly should accommodate the Eco blended new drop in replacements.