Fridge that uses little, if any, of your battery!

[OzeLouie]

Originally Posted by Richard Kollmann

I am with you on batteries and charging current but I do not think the pleasure boat refrigeration companies will agree with your energy to freeze a eutectic plate producing equal energy when melting melting. I am still waiting to hear from those who believe energy is created inside eutectic plates.

No one claims energy is created in a eutectic tank, energy is stored. Suggest look up 'Latent heat'

[Uncle Bob]

Originally Posted by Richard Kollmann

I am with you on batteries and charging current but I do not think the pleasure boat refrigeration companies will agree with your energy to freeze a eutectic plate producing equal energy when melting melting. I am still waiting to hear from those who believe energy is created inside eutectic plates.

Richard, you have been pushing this barrow for quite a long time, I haven't seen anyone here suggest that is the case. What has been said is that when a eutectic system is pushed to cycle at a time of abundant power availability using power that would otherwise not be stored, it eliminates the cycle that would otherwise occur at a time when the power would have to come from the battery.
This is effectively storing the energy that would otherwise be lost. Not having to cycle at night the system saves that energy.
Really simple and practical when you think about it.

[OzeLouie]

Its a pity that this thread intended to indicate that a fridge can be used on board with little if any battery drain, has been highjacked by so many. The issue of refrigeration with as little, if any, battery involvement is of immense interest to boaties everywhere especially cruisers
My apologies for my clumsy OP. My first language is not English and I did mess up the estimator when I diligently removed any reference to our company.
Having said that the theme of my OP was to encourage discussion about how the reader could apply refrigeration without the grief of extra batteries. I doubt that if any of them give a stuff about "There are 24 x 60 x 60 = 86 400 seconds in a day.So 433 Watts for 1 day is 37 411 200 Joules. " etc ect.
Lets all get down off the soapbox and get back to discussing how refrigeration can be engineered to be provided without those extra pesky batteries.

[Dsanduril]

Well, if you want to get back to your desire for the thread...

I get the idea of using “excess” solar power when the batteries are full. I do it myself extensively. However, we use it for “discretionary” loads - things that I don’t absolutely need to run every day - at least on our boat refrigeration is not in this category. The reason for this choice is because sun/wind aren’t reliable.

Our largest use of excess power is making water, on days when we have extra power we make water, on days when we don’t have power we don’t. The advantage to this over refrigeration in this role is that my water tanks can hold a week (actually a lot more if we are even remotely careful) of water. The eutectic system you’ve described can only hold/store a day of cold. So on days with no solar/wind you have to use the batteries to run it - you don’t have sufficient storage to ride through the poor production days. That in turns means you can’t really go smaller on the batteries, you need the bigger set to handle the refrigeration load on the bad days. In the end this means all you’re saving is a few battery cycles, not battery bank size or cost.

So, what is the cost differential between the proposed eutectic system and the USD$500 105l fridge that we currently run at 350-400Wh/day?

[Dockhead]

Originally Posted by Richard Kollmann

The question I have for others to answer is, Are the Btu's of melting eutectic ice equal to the amount of Btu energy required to create eutectic ice? If answer is Yes or No explain.

The answer to your question can be found in Noether's Theorem, which is the basis for the Law of Conservation of Energy.


Of course energy which goes to change temperature and make a phase change in one direction, is the same as the energy coming out from the same temperature change and phase change in the other direction.



Whether it all comes out as heat is a different question, but the answer to that is almost perfectly yes.

[Dockhead]

Originally Posted by joelhemington

As all we Luddites know (yes. I'm a Luddite and proud of it) To reduce energy consumption in your frig or freezer all you need to do is fill all unused space with plastic bottles full of water. Less dead air space will give you much better efficiency regardless of your understanding of electrical issues.

My father was just such a Luddite -- he used to yell at me for leaving the fridge door open when I was a little kid.

But he was as wrong as you are. The numbers show why:

The specific heat of water by volume is approximately 3342x greater than that of air.

So the maximum possible air contained in a typical 80 liter marine fridge contains as much heat energy as 24ml of water at the same temperature. So you could open the door of an empty fridge and let all the cold air drain out, so that the air is entirely repaced by room temperature air 14 times, and the cooling required to cool all that air (80 * 14 = 1120 liters) is the same as putting a single room temperature 330ml can of coke in the fridge. Actually even less, because the can of coke also has some metal in it.

So that's a big bunch of nothing -- nothing more than an old wive's tale.

If it were otherwise, then front-loading fridges would be dramatically less efficient than top loading ones, but they aren't.

[Pete7]

Originally Posted by Dsanduril

So, what is the cost differential between the proposed eutectic system and the USD$500 105l fridge that we currently run at 350-400Wh/day?

Now the answer to that question would be useful to know.

[Richard Kollmann]

Originally Posted by OzeLouie

Its a pity that this thread intended to indicate that a fridge can be used on board with little if any battery drain, has been highjacked by so many. The issue of refrigeration with as little, if any, battery involvement is of immense interest to boaties everywhere especially cruisers
My apologies for my clumsy OP. My first language is not English and I did mess up the estimator when I diligently removed any reference to our company.
Having said that the theme of my OP was to encourage discussion about how the reader could apply refrigeration without the grief of extra batteries. I doubt that if any of them give a stuff about "There are 24 x 60 x 60 = 86 400 seconds in a day.So 433 Watts for 1 day is 37 411 200 Joules. " etc ect.
Lets all get down off the soapbox and get back to discussing how refrigeration can be engineered to be provided without those extra pesky batteries.

Sorry Louie but I thought your thread had al ready been side tracked. I have worked with energy efficiency programs most of my working life. There is and has been a good application in pleasure boat refrigeration in years past for storing surplus energy in frozen liquid tanks.
Thirty years ago most marine refrigeration companies almost all offered in their ice box conversion unit’s energy storing eutectic plates. My reason now for asking questions is why there is only two or companies offering eutectic plates for what may have been twelve in the US. Maybe the eutectic plate industry realized small DC compressors do not offer adequate surplus plate latent energy.

Do you really believe Eutectic plates will reduce need created by refrigeration for large capacity batteries? Batteries and engine alternators make up the basic power grid for most production boats. I am glad most boaters and Louie agrees alternative power generation is required to boost power grid, is a must with eutectic plates on refrigerated boxes over three cubic feet in warm climates.

[hzcruiser]

Originally Posted by OzeLouie

[...]
Having said that the theme of my OP was to encourage discussion about how the reader could apply refrigeration without the grief of extra batteries.[...]

Not sure what sort of "discussion" you expected from a post that seemingly wants to state a fact, given the first line reads:

"It can be done and here is an example:"

[BlackHeron]

Originally Posted by OzeLouie

To automate your second start for the day and have it then function between cut in (SET) and cut out (SET + HYS) simply apply a 300k resistor across the external probe terminals with a push button switch in series. This momentary resistance will put the controller into 'run mode, simply press the button and forget.

Louie

Thank you so much! That modification will make my wife very happy. I can run a 2-conductor cable and set a momentary contact switch and inline resistor near the remote panel. I am planning on setting a dedicated DC power usage meter from a ground shunt near it also so I can track power usage of just the fridge over time. That takes a 4-conductor cable from the shunt, so just two more wires for the start switch while I am at it

No more ruined bell peppers, zucchini squash, and baby spinach. The afternoon run cycle is usually a short one since the plate temperature has usually only risen to about -4C in the few hours since the mid-morning big run cycle. By the time ECO2 would cut in on its own the sun is going down or we are shutting down the engine (when moving) and then it is too late.

This will help a lot and make my wife very happy.

Crusiers Forum is sort of a pit of vipers. I wouldn't get too down on the typical responses to your thread here. I've noticed that many of the people on CF are not cruisers at all but weekenders or occasional once or twice a year vacation boaters if they own a boat at all and aren't just wannabe dreamers without one yet. These probably are not your typical customer base.

I first saw your product on a YouTube video called Follow The Boat. Actual cruisers out living the life.

[hzcruiser]

Originally Posted by BlackHeron

Thank you so much! That modification will make my wife very happy. I can run a 2-conductor cable and set a momentary contact switch [...]

Wouldn't it be "automatic" if the compressor would kick in "automatically" in the afternoon rather than you or your wife pressing a button?

[...] These probably are not your typical customer base.[...]

So the post was directed at their "typical customer base" ? Hmmm..

Either way, maybe Ozefridge is adding this "boost" button to their products, as I'm sure their solution works just fine, no matter what units they're using in their calcs? Or having a smart fridge/freezer, which gets turned on (automagically) once the charge controller goes into float mode?

[Coolerking]

If anyone here would like real info on eutectic plates, their manufacture, use and care, PM me.
Our company has been building them for 30+ years, for boats of all sizes.
Many companies that build refrigeration in fact buy them from us.
This will be my only post in this thread.
Have a good one!

[sailorboy1]

Originally Posted by Richard Kollmann

Sorry Louie but I thought your thread had al ready been side tracked. I have worked with energy efficiency programs most of my working life. There is and has been a good application in pleasure boat refrigeration in years past for storing surplus energy in frozen liquid tanks.
Thirty years ago most marine refrigeration companies almost all offered in their ice box conversion unit’s energy storing eutectic plates. My reason now for asking questions is why there is only two or companies offering eutectic plates for what may have been twelve in the US. Maybe the eutectic plate industry realized small DC compressors do not offer adequate surplus plate latent energy.

Do you really believe Eutectic plates will reduce need created by refrigeration for large capacity batteries? Batteries and engine alternators make up the basic power grid for most production boats. I am glad most boaters and Louie agrees alternative power generation is required to boost power grid, is a must with eutectic plates on refrigerated boxes over three cubic feet in warm climates.

I feel solar has greatly reduced euteric plate use. These made more sense back when you had to run the engine to charge so you may as well taken advantage and froze the plate at same time.

[Off Trail]

Originally Posted by sailorboy1

I feel solar has greatly reduced euteric plate use. These made more sense back when you had to run the engine to charge so you may as well taken advantage and froze the plate at same time.

And with the charging efficiency and acceptance rate of lithium batteries, the ability of the holding plate to bank energy is even less interesting. Let the solar max out the batteries. The energy can then be used for a variety of purposes, unlike heat energy which can only be used for refrigeration.

Makes sense, maybe, for small boats that can't fit the solar.

[Richard Kollmann]

Originally Posted by Off Trail

And with the charging efficiency and acceptance rate of lithium batteries, the ability of the holding plate to bank energy is even less interesting. Let the solar max out the batteries. The energy can then be used for a variety of purposes, unlike heat energy which can only be used for refrigeration.

Makes sense, maybe, for small boats that can't fit the solar.

A current survey would be interesting of what wattage size solar panels are you using to support 50% of your refrigeration electrical power needs, per cubic foot (28 liters) box per day.