Refrigeration - Evaporator vs. Holding Plate

[Richard Kollmann]

Originally Posted by RaymondR

I'm fairly certain Ozylou's employer Ozyfridge would have tested the eutectic solutions they use to see whether the concentrations they specify have any significant freeze temperature range problems, they seem to be fairly thorough sort of people with an inclination to support their theoretical musings with empirical methods.

They also appear to be fairly innovative with the way they designed their dual water/air cooled condensers and their method of avoiding over-condensing and controlling the balance of refrigerent volume between condenser and evaporator whilst using the simple capillary tube flow control device and minimizing cooling fan power consumption.

I am sure all your assumptions are correct it is a well designed but a complected unit.

[Uncle Bob]

Originally Posted by Richard Kollmann

Yes I am sure having spent thirty years in the eutectic plate business and many systems sold used my methods to record their systems performance a few were in my 12/24 volt book. You are correct eutectic plates on a live aboard boat do not have to be completely frozen every morning. A point to remember is the plates mentioned on this thread are not true eutectic solutions so if your are looking to maintain a narrow box temperature the plate must be cycled several times. Temperature drift is not always a problem on beer coolers though.
You should know by now that it is important to question any and all posts here by searching the web for answers to engineering and supporting info. I enjoy being questioned as long as it is maturely presented with no agenda, I will do my best to reply honestly. I look to boaters like you to be the arbitrator when you see opposing what are claimed to be facts.

Richard, I have asked this before and been ignored so I will ask again, why do you persist in belittling Ozefridge and disparaging their product while so many have attested to the products performance as bieng to or above the described performance specs?
They produce a very good reliable refrigeration system, have done for many years I believe and continue to develop and support it.
I have to ask, WHY the continued belittling of every post of firstly Pete and now Louie.

[RaymondR]

Scenes From The Fridge Rebuild

It did say on the can "Super Expanding"

[Uncle Bob]

Originally Posted by RaymondR

Scenes From The Fridge Rebuild

It did say on the can "Super Expanding"

Definately true to the description.

[Richard Kollmann]

Good Relationships and Customer satisfaction documents sell more equipment than insults.

I have been advised to just ignore Louis and Uncle Bob’s insults by forum administrators. Ozefridge, as far as I know has an excellent refrigeration system for the right application such as for of f the grid refrigeration. Over the years I have been involved in all forms of boat and stationary refrigeration designs and when able provided free service calls within the USA. At one time my library of marine mobile refrigeration contained every type of pleasure boat refrigeration with their, manuals, service bulletins and typical repairs.

I have never seen a Ozefreeze refrigeration unit nor would they ever answer one of my technical requests for information as they are a preparatory design company. I only know of two of these units in the US, for the above reasons I have not commented on Ozefridge systems directly. When I have found what I believe are flaws in other manufacturers units like Frigoboat or Adler Barbour I have pointed them out.

It is true I do debate Louie when he gives what I believe to destructive instead of corrective advice on other manufacturers system.
Humor towards yourself is funny but not when making fun of the intelligence of someone senior with more actual appearance, it is also bad for business imaging.

[Bowdrie]

The "Evaporator vs. Holding Plate" is a false narrative, either may be right or wrong depending upon the requirements of the user,, and their is a lot of overlap in applications pertaining to small sailboats.
As to Benefits and Improvements in more modern systems,, well, the physics of the refrigeration cycle haven't changed, their still is no free lunch.
The biggest "improvement" in refrigeration for boats is not so much the equipment itself, but the availability of alternate power sources.
The availability of solar/wind power generation at a reasonable cost is the biggest driver that has made the little 12 volt units a viable option.
In the past, if a sailor wanted a good freezer he would need huge cold plates and an engine driven compressor.
Today even smaller boats have a couple of acres of solar panels and a decent battery bank.
I used to tell people; "Fifty bucks worth of insulation will do you more good than 500 bucks worth of refrigeration equipment".
And, that still holds true,, but now everybody wants a reefer/freezer big enough to put a whole beef carcass into.

[newhaul]

Originally Posted by Bowdrie

The "Evaporator vs. Holding Plate" is a false narrative, either may be right or wrong depending upon the requirements of the user,, and their is a lot of overlap in applications pertaining to small sailboats.
As to Benefits and Improvements in more modern systems,, well, the physics of the refrigeration cycle haven't changed, their still is no free lunch.
The biggest "improvement" in refrigeration for boats is not so much the equipment itself, but the availability of alternate power sources.
The availability of solar/wind power generation at a reasonable cost is the biggest driver that has made the little 12 volt units a viable option.
In the past, if a sailor wanted a good freezer he would need huge cold plates and an engine driven compressor.
Today even smaller boats have a couple of acres of solar panels and a decent battery bank.
I used to tell people; "Fifty bucks worth of insulation will do you more good than 500 bucks worth of refrigeration equipment".
And, that still holds true,, but now everybody wants a reefer/freezer big enough to put a whole beef carcass into.

3.5 cf refrigerator and 1.5 freezer with a 2 inch plate and 2 inches of cryogel 8nsulation R16 per inch

[Pelagic]

Originally Posted by OzeLouie

Komusta ka Pelagic...

Yes some courier systems / customs don't allow us to send with eutectic solution. It has to be added upon installation albeit mounting much lighter empty eutectic plates has some advantage.

Decades ago the Tectaloy product was among many we tested and proved to be the most consistent and uses 'nucleated water and metal inhibiters.



To test for phase change range....

1: Off the unit and observe eutectic mass until it mostly thaws. Note temp on digital controller.

2: Switch on system (Manual switch) and observe the temperature reduction rate.

3: The rate will be relatively quick until phase change commences then appear to stall (flat line) for a few hours.

4: After phase change is complete, the temperature should again lower more rapidly.

5: The period / temperature range noted as described in 3 above, is your phase change area. Expect this to be over a range of 2-3C for fridge and 3-5C for freezer solutions.



If phase change occurs at a temp too low or not at all (remains a liquid) then replace say 15% of the mix with water, conversely if the phase change occurs too early (remains frozen) then replace say 10% of the mix with pure glycol. May have to repeat to get the best results.



I hope this helps... Louie

Thanks Louie, never thought of using the rate of Temp Change as an indicator..... makes sense

Say hi to your dad !