Effective Eutectic solutions from the food industry

[bdgWesternMass]

I'm currently looking at Phase Change Materials

This company advertises such products
https://www.pcmproducts.net/Eutectic...ation_PCMs.htm

I picked the E-range PCM as an example which has a range from 0/32 to -65/-85

A 62 pounds or one cubic foot of this material I believe holds about 10,000 BTUs

Here is a table of
https://www.pcmproducts.net/files/Pl...e%202021-1.pdf

Feel free to fact check me

[Richard Kollmann]

Originally Posted by bdgWesternMass

The ozfridge seems to a good proof of the value of the eutectic plate refrigerator.

Although the express the energy usage in AMP/H per day for a 12V DC system I will express them in the less controversial for of watts per day.

Rounding the Amps up to the nearest whole number of 4 at 12 volts I get 48 watts per day.

Finally our own thread participant Richard Kollmann is quoted defining his process of estimating refrigeration loads.

If one was designing a refrigerator today can they still use your estimating guidelines Richard?

Thanks,

Ben

The figures in cruising world and on my slide show or worst case refrigeration design planing figures used to select refrigeration system.I have not found in the last 25 years any changes today of energy reductions to the systems in that earlier comparison relating to Eutectic Evaporators. Any improvements to today's small 12 volt refrigeration has been the SCOP resulting from variable speed compressors and other sources of energy other than house battery.

As far as I know the same volume of energy is stored in each equal size eutectic plate regardless of eutectic fluid used or its eutectic freeze point. Water Ice holds freeze point temperature the longest, Glycol/water Ice temperature is not stable and continues to rise slowly when compressor stops Requiring larger plates or more frequent cycling of compressor. Even with the best true eutectic you will not increase energy stored an perishable amount.

I would worry more about the design of evaporator in plate to absorb heat fast enough, by eliminating heat flow resistance box to refrigerant.

[bdgWesternMass]

Wow this is great info. I feel pretty lucky to have access to your experience.

I will use a cubic foot of ice as my control/reference material.
I'm thinking of system that would store solar over production as "ice".

So I will be oversizing the storage load/eutectic plate size compared to a sensible system.

Finally do you have a perspective on how insulation may have changed things over the past 25 years?

I ask because I'm looking at using aerogels for my panels.

Thanks,

Ben

[Richard Kollmann]

Originally Posted by bdgWesternMass

Wow this is great info. I feel pretty lucky to have access to your experience.

I will use a cubic foot of ice as my control/reference material.
I'm thinking of system that would store solar over production as "ice".

So I will be oversizing the storage load/eutectic plate size compared to a sensible system.

Finally do you have a perspective on how insulation may have changed things over the past 25 years?

I ask because I'm looking at using aerogels for my panels.

Thanks,

Ben

Remember two things about refrigeration Closed cell insulation keeps heat out and open cell is intended to keep cold out and warm in. Both open and closed cell types of insulation act as Dehumidifier of moisture in air circulating in and out of refrigerator insulation each time compressor cycles. To prevent moisture being left in insulation as it leaves insulation cells. To prevent loss of insulation R value refrigeration insulation should be tightly encapsulated and sealed in builders plastic. Closed cells tend to out gas the cells over time.

[OzeLouie]

Originally Posted by Richard Kollmann

The figures in cruising world and on my slide show or worst case refrigeration design planing figures used to select refrigeration system.I have not found in the last 25 years any changes today of energy reductions to the systems in that earlier comparison relating to Eutectic Evaporators. Any improvements to today's small 12 volt refrigeration has been the SCOP resulting from variable speed compressors and other sources of energy other than house battery.

As far as I know the same volume of energy is stored in each equal size eutectic plate regardless of eutectic fluid used or its eutectic freeze point. Water Ice holds freeze point temperature the longest, Glycol/water Ice temperature is not stable and continues to rise slowly when compressor stops Requiring larger plates or more frequent cycling of compressor. Even with the best true eutectic you will not increase energy stored an perishable amount.

I would worry more about the design of evaporator in plate to absorb heat fast enough, by eliminating heat flow resistance box to refrigerant.

Richard there have been many changes to the eutectic systems offered in that period and the main reason I have often asked you to post technical detail, data, drawings, pictures, web site references, in fact anything that depicts your hands on manufacturing involvement, so we can compare where improvements have been made or not.

Why won't you do that? It's is a pity as it would give credibility to your nowadays anti eutectic stance and allow discussion with meaning?
All the waffle in the world or citing what someone said 30 years ago means nothing unless supported by factual data as a result of actual hands on experience with much testing and trials of concepts including data derived and made available to support your position.

BTW, Again I have to say pure water alone, although the best phase change material as RK mentioned, should not be used in sealed eutectic tanks. Add glycol.

[wsmurdoch]

I have a Kollmann Marine Products refrigeration system -- a hybrid system with both an engine driven compressor with a water cooled condenser and a electrical condensing unit with an air cooled condenser both cooling a holding plate in my freezer which in turn cools the refrigerator by a spill over fan. The engine driven system also includes a "Freeze Blast" after the holding plate, a fan and extended surface area coil to speed the cooling when the engine is running. I believe the equipment is as old as the boat: 1988. The system still works. It is absolutely reliable, and because it is constructed from standard parts that are still available today, it is easily repairable anywhere by a skilled owner or local technician.

My wife and I have cruised the Bahamas for 12 winters keeping beer and veggies cold, and meat frozen.

Old copies of Cruising World Magazine available on Google Books contain advertisements for these Kollmann Marine Products systems. Although my system is a "factory" system, its design closely matches the description of one of the several systems described in Mr. Kollmann's book "Do-It-Yourself Boat Refrigeration". Copies occasionally show up on Amazon, ebay, or Abebooks --
both old (1984)

and new (2000).

They (and a later similar book on 12V refrigeration)

are books that Mr. Kollmann wrote to guide cruisers who wished to build or maintain their own refrigeration systems. The books are not technical tomes but are like the knowledge that a journeyman would pass to his apprentice.

In addition, Mr. Kollmann (in retirement) for years has provided assistance to many cruisers by phone, by personal email, through his web sites, and on this forum. I and others have benefited from his guidance and advice for which he has received no benefit.

Bill

[rgleason]

Thanks WS,

I think I have "Do-It-Yourself Boat Refrigeration" in my boat bookcase, and have referred to it and found it useful.

You wrote:
"...a holding plate in my freezer which in turn cools the refrigerator by a spill over fan. The engine driven system also includes a "Freeze Blast" after the holding plate, a fan and extended surface area coil to speed the cooling when the engine is running."

This is an interesting idea, use a fan to try to accelerate cool down of food in the chest when there is extra energy. The use case for me might be midway or towards the end of the first draw down after we have loaded the fridge and started the compressor. However I am not sure how much that would help as the compressor has a big enough job changing the state of the evaporator eutectic tank.


RK wrote:
"Any improvements to today's small 12 volt refrigeration has been the SCOP resulting from variable speed compressors and other sources of energy other than house battery."


Yes, those improvements have been significant enough to reduce the use of direct engine driven compressors in favor of electrical energy sources.




----


Dear Louie, I am very sorry to learn about your Dad, and we are all hoping for the best for him. I faced some of this last year (am clear now and hope to be lucky). I think biggest gift you can give is to spend time with him and possibly talk when he is up to it. Of course your responsibilities are greater now so you will also be very busy too, so you'll have to be focused and balance your time.

[RaymondR]

In his Refrigeration for Pleasure Vessels Nigel Calder appears to advise against the use of glycol water mixes as eutectic fluids. He refers to them as antifreeze solutions and explains that unlike true eutectic solutions they tend to freeze over a range of temperature and are inclined to separation. He also explains that because of the significantly lower temperatures the system must work at to continue the freezing process at the lower temperature end significant detrimental efficiency effects occur.

I vaguely recall that freeze separation is a technique used in chemical separation and if so he could be right.

[rgleason]

Ocean Navigator: From state of cool optimal temps for freezer and veggies, true eutectic vs glycol

Theoretical Aspects of Freezing Process including freezing ice cream

PCM Phase Change Manufacturer A range of solutions

Insilico PCM Microcapsule Might be a source of some ideas.

Nelson details about cold packs

PureTemp - Comparison of PCM

Andor - Effective Eutectic

Phase Change Solutions BioPCM

Truck body eutectic plates

Use of PCM for improving cold storage

PCM Phase Change Material Use in cold/hot food boxes asks a question How can I speed up the freezing time? ".. the eutectic plates must be separated from one another in the freezer, at least by 3 cm. If they are piled up, the cold air cannot circulate between them, which significantly increases the freezing time."

Would an evaporator tank configured as a thinner double plate speed up freezing period? Probably not because the cooling is coming from the evaporator cools inside the tank, rather than outside the container as in this example, also the small compressors and evaporator coils may be a limiting factor to faster cooling.

[wsmurdoch]

I spent some time looking at alternatives to the PG/water mixture that is in my holding plate. It is hard to find something better; better being storing more "cold" per pound and being capable of freezing faster. The fluid needs to...

Absorb and lose significant heat when cycled between say 20F and 0F
Having a freezing point or a small freezing range between say 20F and 0F
Have a high heat conductivity
Have a low viscosity
Be chemically stable
Not be poisonous or noxious
Not be corrosive to stainless steel, copper, or solder
Not be an electrolyte causing galvanic corrosion my plate of copper and stainless
Not be subject to biologic attack when stored warm for long periods
Not burst equipment on freezing.

I spent time in both my employer's technical library, patent files, and manufacturer's literature files looking for a better fluid. I found nothing better. Glacier Bay claimed to have better in their TSS+26 and TSS-8 solutions (which I suspect were sodium/potassium nitrate solutions in water and may have caused their change to all stainless plates), but I have not found their compositions. I did find lots of marketing hype and misstatement. ...and Glacier Bay went out of the business.

[rgleason]

Good list of requirements.
Louie suggested I contact someone about vacuum insulation panels. That person suggested Glacier Bay Barrier Panels and I found them at
Glacier Bay Insulation Test Results Table
Price List - Glacier Bay's BARRIER Superinsulation vacuum insulation panels.


I wonder why they are still available?

[wsmurdoch]

In my memory the business went from Glacier Bay to Pacific Sea Breeze to Rparts (rparts.com). The panels are expensive, they can not be cut, drilled, or modified by the user, a puncture is a failure, and long term gas permeation through the barrier is a failure. But, for their thickness they have a low heat transfer coefficient.

[RaymondR]

It appears to me that the real problem here is not the availability of effective eutectic solutions, there appears to be a plethora of them, but either finding one which does not bring with it unacceptable corrosion problems or alternatively, designing eutectic tanks more resistant to corrosion.

[bdgWesternMass]

Originally Posted by rgleason

Ocean Navigator: From state of cool optimal temps for freezer and veggies, true eutectic vs glycol

Theoretical Aspects of Freezing Process including freezing ice cream

PCM Phase Change Manufacturer A range of solutions

Insilico PCM Microcapsule Might be a source of some ideas.

Nelson details about cold packs

PureTemp - Comparison of PCM

Andor - Effective Eutectic

Phase Change Solutions BioPCM

Truck body eutectic plates

Use of PCM for improving cold storage

PCM Phase Change Material Use in cold/hot food boxes asks a question How can I speed up the freezing time? ".. the eutectic plates must be separated from one another in the freezer, at least by 3 cm. If they are piled up, the cold air cannot circulate between them, which significantly increases the freezing time."

Would an evaporator tank configured as a thinner double plate speed up freezing period? Probably not because the cooling is coming from the evaporator cools inside the tank, rather than outside the container as in this example, also the small compressors and evaporator coils may be a limiting factor to faster cooling.

Gunthela Enterprise - Product Catalogue

Here is a source for Eutectic plates for the food industry not on your list.
I like the rawness of theses panels and will be trying to design a multi-stage system. I'm going to use 6 cubic feet/ .17 cubic meters. As my storage capacity.

[OzeLouie]

Originally Posted by RaymondR

It appears to me that the real problem here is not the availability of effective eutectic solutions, there appears to be a plethora of them, but either finding one which does not bring with it unacceptable corrosion problems or alternatively, designing eutectic tanks more resistant to corrosion.

Yes, the issues are as you say but add in availability world wide, does it have suitable metal corrosion inhibiters, and most important that the PCM can expand while still fluid otherwise your sealed eutectic plate / tank will end up looking like a pumpkin!!

After much searching and testing we concluded that most PCMs had similar performance outcomes but were less practical because of issues stated here, and we were specially concerned long term with those salt based. Those automotive anti freeze products have excellent metal inhibiters, do not separate, are well tested in a very competitive market, and are readily available.

While water is the winner with a narrow phase change temp range, it is not practical due to its PCM temp and inability to be fluid while freezing (expanding)
Water @ 0C phase change requires 93 watts of latent heat per litre removed or added to freeze or thaw, while a 10% / 90% water mix (for fridge cabinet 1c to 5c) will require approx 85 watts of latent heat per litre to freeze or thaw. The result is that the amount of PCM required (litres) to store enough energy to hold-over your cabinet is marginally greater with glycol based (and others!) but thereafter the benefits are the same. The overall performance has mostly to do with the refrigeration systems ability and little to do with the rather dormant PCM facility part of the system. A correctly engineered eutectic system with a *10% PCM mix in a correctly insulated fridge cabinet, will see a cabinet product temperature range of between +2C & +4C
(*Measuring PCM, set 'SET' at -10C unit off & 'HYS' at 8C unit on -2C providing a phase change range from approx -2C to -5C phase change and a ideal cabinet product temp of +2C to +4C)

Note that many eutectic systems now used commercially for perishable goods transportation are re-frozen in a special freezer and don't have internal evaporators to deal with.
This introduces another fridge cooling option for weekend only users: Make a ss eutectic tank the suitable size with a sealable filler cap, fill to 90% full with a 10% glycol / 90% water, stand in home deep freezer and once frozen solid, seal cap. When heading out, remove at carry to boat in a suitable bag / container, put in the boats ice box and cold beers to follow. Good for two days or more then return back to the deepfreeze at home until next outing!