CoolBlue - is it worth the extra $$$

[a64pilot]

Originally Posted by missourisailor

Please correct me if I'm remembering wrong, but on a previous fridge thread wasn't it stated that the "freezing water jug" theory was indeed a false theory?

Do we now have a new thought on it?

The freezing water jug thing does nothing to increase efficiency, or does very little anyway, but the idea here is to use it as a sort of flywheel for those times when you have excess Solar that is going to waste you can store some energy in those jugs for later when there is no excess Solar.
But your right, the total AH used on a 24 hour period will not change, so no change in efficiency.
You can of course do the same or similar by adding another battery to your bank, store the power there as opposed to doing it in jugs.

More of a hypothetical scenario than something that is practical.

[SV THIRD DAY]

First call me Rich, "Mr Boren" is what my kids friends call me and it makes me feel old...ha ha

I'm always happy to answer questions, especially when doing so means I have an excuse to not have to start working on my Teak Deck Replacement project when I first wake up in the morning! As an ADD/AHDH person, it is easiest for me to take the questions in order so I don't lose track where I am. Some people can misinterpret that approach is being overly anal..ok..so maybe it is, but that's just who I am. So lets dive in...if you have any follow-ups, shoot them away and I'll be happy to help.

Originally Posted by ErikFinn

I would have a question to Mr. Boren about the CooldBlue system please. Searching through the company's website I presume the "Coolblue" is the only kit system you currently offer, not including the upright "EcoFridge" fridges (not interested in those ones).

For a standard off the shelf unit, you are correct.
Over the years we have identified the standard sizes of holding plates (listed on our Holding Plate Options tab) that will fit into most boxes, so then the client just picks the holding plate orientation and copper tube length for his installation. So many times the "options" turn into up-sales gimmicks and just add to product confusion in my opinion, so if something is needed to make the unit efficient, why call it an option? Why not just include it our get rid of the fluff? Going into crazy techy detail on the website just loses most people, so we don't have an online "But it Now" shopping cart where you mix and match components. We talk to each client and review their box data (size, insulation, layout) and make sure the system we are selling will work for THEIR application, not that of their dock neighbor. That takes more time, but it also leads to happier clients.

For clients that have bigger boxes or special applications (like a64pilot) we can build custom systems if needed and that is something we do all the time. Custom size holding plates, larger single compressors for a client that doesn't want two, etc.

Originally Posted by ErikFinn

I understand the CoolBlue uses the Cubigel GD30FDC compressor, which I believe to be similar in performance to the Danfoss/Secop BD35F, is that correct?

I think I mentioned it earlier in this thread, but when Danfoss was purchased and had their production moved from Germany to China, we saw a huge drop in quality. Increase controller burn outs, some units not working properly right out of the Box, etc. So we switched to the Cubigel compressor made in Spain. Now to be fair to Danfoss, I believe they have worked through those problems, but once we made the switch we found the Cubigel to be of better quality, so we figured why change back. Lets stick with what works, that's a big part of our 5yr warranty when others are 1-2yrs.

Regarding performance, the name of the Cubigel compressor is unfortunate and leads to an easy false assumption that the GD30FDC is equivalent to the Danfoss BD35F. The 30 and 35 reference. But in fact, it is equivalent to the BD50.

Originally Posted by ErikFinn

I tried to find performance specification for the CoolBlue kit, with regards for usage in tropics, for a 200 liter freezer with 10 cm (about 4inch) PU foam insulation, old school bad insulation stuff, no Cryogel Z R30 here...

Ah the Holy Grail of data...that is always just around the corner of discovery but always out of reach. No one really gives the power usage for the tropics...why...because for what boat? What size of Box? For what level of insulation? How much Cold Beer and water do you drink per day? For how many crew members? Top loader/Front loader? Are you happy with a 13-deg freezer or do you want a 4-deg freezer. Now this may seem like a cop-out, but it's just the flat honest truth and ANY vendor of a marine refrigeration unit that says he can tell you the exact power usage YOUR boat set-up will use is either a bozo or a salesman.

So how can we plan, how can we compare the systems and know what works best? Well sadly that's part of the problem and something that leads to much confusion in the industry. Some of it on purpose to keep things hard to compare, but much of it just the reality that boat boxes and cruising circumstances are different.

Rather than try to have a data point for every Box Size, insulation, ambient temp, and user profile, what we have done is to give our standard box performance data:
A 7CF Box with R30 insulation (4" or quality foam) divided in the standard spill over set-up with 1/3 freezer and 2/3 refrigerator space. The test was conducted at 70-degs F. The average daily Amp hour usage was 24AH and the compressor cycled on/off 4 times per 24hrs. This compares to the standard CU200 capillary evaporation plate that used about double the power during the test run.
Now if your insulation is less, you will use more amps.
Bigger Box volume, you will use more amps.
Hotter Ambient temps, you will use more amps.
But sure our unit will use more amps...but so will everyone's else, so the best system starts as low as possible for a baseline and then when the numbers rise along with everyone else's yours will still be lower.

Anecdotal examples of what people's power usage is for their refrigerator/freezer is usually pretty worthless because given along with it is usually not enough data to know what the AH means and how to relate it to you, but we have been in business since 1968 and there are lots of data sets out there on how our system performs and ranks. We wouldn't be selling 20-25 of these system per month if it was all based on a lie.

For your 200L box in the Tropics with "ok" but not great insulation...1/3 freezer and 2/3 freezer...a good honest guess on power usage would be between 30-50AH/Day. The thing about exaggerations is that they always come to light when the client puts an Amp hour meter on his system...so truth and honestly is better than BS

Originally Posted by ErikFinn

I was under the impression that a Danfoss/Secop BD35F could never manage this kind of a BTU demand. Not even a BD50F would suffice, or so I've understood. One would possibly have to go to a BD80F to have a chance. With air cooling, no water cooling.

That is just not my real world experience with refrigeration in the tropics.
Forget who's unit they have but a BD50 or Cubigel GD30FDC is perfectly capable of dealing with a 200L (7.06CF) box with decent insulation. There are thousands of them doing it all around the world. But decent insulation is the key because no matter how efficient your refrigeration system is, if more heat is coming into the Box than the compressor can remove...adios amigo. This is also one of the hardest things to honestly know because most people don't want to try and calculate the R-value of their Box and even if they know it, most don't want to go through the drama of resulating their Box.

So much of the Air vs Water cooling myth for the tropics I think comes form the AB CU200 with or without the water cooling option. Right in their manual it says that at ambient temps above 90-degs F you need to add water cooling. So of course if you are in the tropics then you need water cooling right? Well on their design yes you do, you do IF you don't want to lose some condenser and thus compressor efficiency. But what's not understood well is that they need water cooling due to the size limitation on their condensing unit. It's a design limitation on their particular system, not an indictment of water vs air in general. Do away with that limitation and you can raise the operating temperate of your condenser up to 120-degs F without compressor efficiency loss and now say adios to water cooling, like we have done. It's about the entire system design not just about air vs water as a heat transfer medium, that that hangs up a lot of people.

Originally Posted by ErikFinn

So, that leads to my question, I have understood that the CoolBlue is more efficient than a system with a Danfoss/Secop BD 35F compressor, have I misunderstood or is the CoolBlue really more efficient?

In a sentence:
It's not about the compressor...it's about the overall design the compressor is used in that matters.

For example:
Take two CoolBlue systems side by side, one with a Danfoss BD50 and one with a Cubigel GD30FDC compressor. Which is more "efficient"...and which can pull out more heat from the box...neither. The compressors are nearly identical.

Now take Two identical compressors (Danfoss BD50 or Cubigel GD30FDC) and put them in the CoolBlue configuration with a Thermally Adjusting Expansion Valve with eutectic holding plate and the other in a fixed critical orifice rolled thin aluminum evaporator. Now ask the question again, which is more efficient? The CoolBlue configuration will then use less power. It isn't that the "compressor" itself is more efficient, it is the overall design that the compressor is used in that matters.

This is another Huge area of confusion and I hear it all the time, especially for the older units that used the Danfoss compressors. "Rich, you are full of bovine excrement you use the same compressor as (insert brand X) so you can't say your system uses less power. All of your test data and independent testing is fake". Trust me...I hear it all and at first it bothered me because I took it personal and I would spend hours in emails and online forums trying to defend our data and power usage, but...
But at the end of the day, I have a test box running at the office showing our real numbers side-by-side with several competitor units. So to be honest, I've somewhat moved on and focus on trying to keep up with orders and customer service than deal with spitballs.

Originally Posted by ErikFinn

Could the CoolBlue handle a 200 liter freezer in the tropics? If yes, what exactly is it that makes the CoolBlue so much better? Surely not just a bigger condenser coil?

Yes...Maybe...No..
Lets make sure we are all on the same page here.
200L is 7.06Cubic Feet so in a standard box with good to Ok insulation divided up 1/3 freezer-2/3 refrigerator yes...no problem. Go to the tropics and have ice cream and cold beer with our standard system. Now if you want a 7CF freezer only with no refrigerator...NO...I would not sell you the standard system, but would recommend you buy a second holding plate to be ran in series to your first. The compressor (with good insulation) could still pull it off, daily power would go up, but you want/need more surface area in the box to reach the lower freezer temps for a box that size. That is what we did for a64pilot...a dual holding plate freezer system.
The maybe part is the Compressor Size..would I recommend going up in compressor size...well that's something that we can talk about for your situation and needs but definitely dual holding plates for a 7CF freezer to get more even temps and colder temps.

At the end of the day it's the overall design not just the compressor that makes the CoolBlue more efficient than some other units out there on the market:
Thermally Adjusting Expansion Valve, Larger condensing unit, eutectic holding plate.
Vs
Critical fixed orifice and rolled aluminum evaporator with no hold over capacity.

[a64pilot]

One thing I could not get my head wrapped around, and I thought wouldn't work.
(I am licensed HVAC tech, no expert though, but I understand the theory)
Is that we were going to use a much larger compressor and double the evaporator by using two holding plates, yet use the same condenser?
How is that going to work? We are going to be dumping likely twice the heat into the condenser that a standard system does, yet still rely on air cooling?
Well what has to be is that the reason a cool blue will continue to work in very high air temps is that the condenser is not marginal at all, there is a lot of excess condenser, or how is it my BD80 compressor with dual cold plates works great with the condenser in excess of 100 degree temps?

[SV THIRD DAY]

Originally Posted by missourisailor

Please correct me if I'm remembering wrong, but on a previous fridge thread wasn't it stated that the "freezing water jug" theory was indeed a false theory?
Do we now have a new thought on it?

No, my lab testing data hasn't changed, so I have no revision on the "false water jug theory" that was debunked in another thread. Perhaps you didn't quite follow the context of my quoted comment, so you took away the wrong impression. So thanks for the opportunity to clear that up before another chat-room-rumor was hatched and allowed to run wild up and down the docks. First let review what I was referencing as a way to gain additional efficiency out of a HOLDING PLATE system

Originally Posted by SV THIRD DAY

That's a smart way to take advantage of the excess power...basically store it in the holding plate, as Richard Kollmann suggests is the best way to get efficiency out of a holding plate system. So there are three ways to do this and like everything, one is free and easy, one is cheap and a little more complex, and the other is high tech, but just costs $$.

Free and Easy:
Install a switch that jumpers around your thermostat so that you can manually turn on the compressor unit when you are motoring, running a ships generator, or have your batteries in float mode by wind/solar. This way you will stuff as much "cold" into the holding plates as possible when you have excess power. The negative is that you WILL forget to turn off the compressor until the next morning sometimes like I did and then you will need to hang a sign up somewhere to remind yourself. Another negative is that you don't want to freeze your refrigerator with things getting too cold, so I wold recommend installing a digital thermostat in the refrigerator so you know what's going on in the box.

Cheap and a little more complex:
Get a voltage sensing relay set at 13.9v (or whatever you call full batteries) so that is closes and opens the same switch as I mention above but does it automatically. This way you eliminate the risk of forgetting to turn on and off the unit manually. The negative here is still the risk of freezing your refrigerator if the unit stays on for a long time....like I did when I motored for 2 days across the Sea of Cortez. (you learn things from your mistakes but I liked the frozen mangos). This is where a digital temp display for your refrigerator and freezer comes in VERY HANDY and I recommend that for every boat anyway, because more data is better....right?

High Tech $$ approach:
Ok, this is the best approach and I've been testing it now for over a year and it works great, but it does cost more money. Use an electronic thermostat that that will sense your battery voltage and then turns on the compressor to take advantage of that "free power" BUT can still turn the system off if you hit a cold temp set point. This way you don't risk freezing your refrigerator. It works by tightening up the hysteresis set-point and going down to a new "coldest" set point.
I've seen as much as a 27% power savings of battery power. A place with hot day and cooler nights will benefit most (as well boats with great insulation) because the system can stay off longer at nights when you won't have that excess solar power. I spend most of my day in float mode with my 1300W of solar. But if you never motor, never run a generator, and never have your batteries up to the Full and float mode...well then this will do NOTHING at all for you, except piss you off that you spent about $275 on it! Remember, I'm a cheap live aboard cruiser myself, so anything I can do manually or on the cheap, I LOVE.

Now, the so called "Water Jug rumor" says that you can save on daily battery usage by simply adding jugs of water to your freezer box. The problem with this myth, is like with most myths. There is just enough partial truth in it to suck people in, but it leaves out some critical information. Simply adding jugs of water to your freezer box won't help with your daily power usage if your system is not set-up and designed to take advantage of the eutectic solution (water in the jugs). It sounds great…but I have to defer to the test data.

But Rich, you just said this…have you lost you brain….

Originally Posted by SV THIRD DAY

Bingo...add a 4th Cheap and Easy way to the list...the frozen water jug trick to store BTUs. But yes, if you don't have excess energy...what is the point.

Ah yes…but I was talking about a system designed around the principals of taking advantage of the eutectic properties of the frozen water jug and having extra power available. That's just totally different than tossing a few water jugs in your freezer and hoping for the best. In fact, on one of our tests data sets that "trick" actually increased the power usage of the system because when the system turned on to re-freeze the water, there was no excess solar power available in the dead of night….so battery power was needlessly converted and stored as Ice…that phase change energy cost is high if not controlled properly.

[Zai]

Maybe a stupid question, but what is a cubic liter?

[a64pilot]

Originally Posted by Zai

Maybe a stupid question, but what is a cubic liter?

No it's not, once I think about it a liter is a unit of volume, not length like say a ft.
I wrongly initially thought unit of length. So I guess saying a cubic Liter is sort of like saying Hot Water Heater

I come into the metric system with a little effort, it is not Native unfortunately

Funny thing is when I googled convert cubic liter to square ft., I got a conversion

[SV THIRD DAY]

Originally Posted by a64pilot

One thing I could not get my head wrapped around, and I thought wouldn't work.
(I am licensed HVAC tech, no expert though, but I understand the theory)
Is that we were going to use a much larger compressor and double the evaporator by using two holding plates, yet use the same condenser?
How is that going to work? We are going to be dumping likely twice the heat into the condenser that a standard system does, yet still rely on air cooling?
Well what has to be is that the reason a cool blue will continue to work in very high air temps is that the condenser is not marginal at all, there is a lot of excess condenser, or how is it my BD80 compressor with dual cold plates works great with the condenser in excess of 100 degree temps?

Ding...ding...give that man a Ice Cold Beer!

And that is where the Thermally Adjusting Expansion Valve or TXV come into play. Put on your snake boots folks, here we go into the techy weeds.

The TXV is throttling more or less refrigerant into the holding plate in order to maintain a 10-deg temperature difference between the inlet and outlet of the holding plate. This means we need a place to store the refrigerant as it waits for the TXV to call for it to flow. So that is why when you look at our Drier/Receiver it's huge it's large enough to contain the entire full charge of refrigerant, which is 24oz. In fact, that is where the refrigerant is stored when the unit is charged after testing at the office. We suck everything out of the lines, holding plate and compressor and store it in the drier/receiver when it ships. What does this have to do with the condenser....EVERYTHING.

Maybe I should have gotten into this to answer the "Why are we more efficient question" posed by ErikFinn, but I just never know how deep in the technical weeds people really want to go and honestly, it takes time to explain this properly, so sometimes I lazy out.

On a TXV system you don't have to have a balance between the compressor suction and pressure side (like you do on a Critical Charge system using a fixed orifice), because you have this huge Drier/Receiver where excess refrigerant "waits". So while it is waiting, why not send it through a condensing unit that is massively oversized?

Bingo...exactly...why not. Now rather than losing condenser efficiency at 90-degs ambient air temps with a small surface area like the other air cool guys do, we up-size it for the US Military Spec for desert application of 135-degs. So you can operate our system up to 120-degs F without ANY loss in condenser and thus compressor efficiency.

It's all about the TXV and what it allows you to then do in terms of system design. Well then...why doesn't everyone use a TXV over a fixed critical orifice system? Simple...Cost. The TXV systems simply costs more to build because they are not stamped out by the Cargo container load in China. We are constantly toying with the thought of selling critical orifice systems for those that want to save a little money, but honestly at the end of the day, we can barely keep up with order now...and I'm in California where hiring a new employee is outrageously expensive, so I'd rather not "grow" and face higher taxes and costs.


Our biggest client is the US Military for 12v/solar off the grid mobile food carts and storage units. 5ftx5ftx5ft internal volume Cubes ran by two of our off the shelf standard CoolBlue compressor units with a 1000W solar array, LiFePO4 battery the PolyIsoCyanurate insulation is 12-18" thick incased in a fiberglass body, of course with helicopter lifting eyes.

So I have to chuckle when people say air cooling can't be done in the Tropics. Well it seems to work in Afghanistan with the exact same off the shelf CoolBlue compressor unit. You can see the square vents in the mechanical room portion of the unit and those are the location of the CoolBlue compressor condensers to pull in cool air. The door/hatch is on the opposite side in the photo.

[Laughing Buddha]

Continuing along the diversion from the thread title...

Jugs of water (frozen) in the freezer.

"Seems to work," intuitive - but, where is the science? (Rich, do you have some test data you can share?)

An advantage you get cold water to drink; added (small) water storage capacity; and you can believe you've improved your hold-over times. Aside from the added advantages above, you still need to freeze that water, and it will thaw at about the same rate as other product in your freezer. And all you get for that is; water.

If you have the capacity to add jugs of water (eaten some of the stores from the freezer) you'd be better off inserting closed cell foam blocks. They require no freezing - but don't thaw so much either. (Well, there will be some energy costs when you add them to the freezer if stored at 100+ as they come to box temp.) Foam blocks can be a PITA to workaround in the freezer, and store when not in use, but they would effectively reduce the capacity of air to be chilled and effectively increase the ratio of plate to box volume. A good thing I say.

Another option I'd ask to explore (as Rich brought up Phase Change) what about using some of the more recently marketed PCMs as hold over?

There are products available that have longer holdover times than the conventional Blue Ice, but most I note change state at higher than freezer temp. That would seem to be an OK thing to add to the 'fridge for overnight holdover, but would require re-freezing during day time runs. Any "goodness" here?

Cheers - Jim

[Richard Kollmann]

After taking one month away from the internet to move from Ft Lauderdale to Merritt Island I am amazed at my back log of 946 emails and how a simple question on this site like “Can a Cool Blue refrigeration system be worth the extra money? In my opinion only when A Cool Blue is used in limited applications where box size and climate conditions are limited. Allowing the manufacturer to spin the Cool blue with variable speed Danfoss compressor’s original repetition by creative advertising indicating performance is far better than other companies equipment is a bit to much. My experience in manufacturing one to 250 holding plate systems for boats over the last 30 years leaves me with the understanding that a holding plates only purpose is to store surplus energy if and when surplus energy is available. A 200 to 300 Btu compressor in a refrigerated box does not provide enough surplus energy to maintain frozen solution in plates unless other alternative energy sources are available from wind, solar and water generators.

I also find it difficult to understand why Adler Barbour and Grunert tried the Spanish compressor and then went back to Danfoss compressors with in a year?

[missourisailor]

What has me perplexed is here we have two, world renown refrigeration experts, spinning two completely different tales.

No wonder most folks think that ice cubes on a boat is black magic.
Even I, with my refrigeration experience, am in a bit of a haze right now.

Sooooo. some questions to both experts.

1) If holding plates are more efficient than thin plates, why does it seem that Cool Blue is the only one still using them?

2) If you had favorable thoughts about Cool Blue with the Danfoss compressors and now you don't because of the Spanish compressor. If they went back to the Danfoss, would you be favorable to a holding plate system?

[Richard Kollmann]

Missourisailor

1) I know of no one in the HVACR industry that would say holding holdover plates are more efficient than conventional evaporators. Other than storing surplus energy, if available, holding plates with large enough eutectic solution volumes can provide a flywheel effect of energy like ice when warm drinks are placed in box.

Storage of energy in ice does have merits in avoiding electrical demand charge penalties in large facilities. Now with the availability to reduce the newer variable speed compressor’s speeds improved system balance will improve most any small refrigeration system efficiency in SMALL refrigerated boxes. When water or solution of liquids are phase changed to a solid form by freezing it then becomes an insulator reducing its effect as an efficient evaporator.

2) Danfoss BD compressors have the lead in volume of hours in service, parts available and knowledgeable service most anywhere. Right now Rich in California is the only source for help on Spanish compressor parts and service.

[missourisailor]

Mr. Kollmann,
Thanks for the response. While we wait for the sun to come up on the west coast, for Mr. Boren's comments (I'm using last names to keep people straight), lets move on and he can play catch up.

Your statement is what I have experienced and have always been taught.
However, in Mr. Boren's test case where he is comparing the Ah of a holding plate system verses a thin plate system, his test are showing that the holding plate system uses a whole lot less Ah's.

The problem that I have with his test is that he has changed TWO variables.
ONE - Holding plaste vs thin plate
TWO - orifice vs expansion valve.

I'm wondering if most of the reduced Ah's is not because of the holding plate but has more to do with the use of an expansion valve?

[kmacdonald]

A holding plate system is NOT more efficient. It's only advantage is being able to use excess energy, when available, to be stored in the holding plates for use when less energy is available. It is only suitable for a refrigerator and should never be used in a freezer.

[a64pilot]

You compare a system to a system, not pieces parts to pieces parts or it doesn't tell much.
Reasoning why a Prius gets so much better gas mileage for example is nearly impossible to put you finger on as it is several reasons, from low rolling resistance tires, to lower coefficient of drag, the engine is not an Otto cycle, energy recovery during braking etc., etc. put it all together and the result is greater than the sum of it's parts.
Then and I am not pointing any fingers, but if I manufactured a product, my testing that I published would of course favor my product.
I wouldn't be testing the Prius at highway speeds or in really cold weather as the great mileage isn't as great then. any manufacturers testing will highlight the strengths of their product. Its why Consumer Reports and bunches of other agencies were born.

But a refrigeration system takes a short time for pressures to build and cooling to begin etc. and until then its not very efficient at all. Think of your AC in your boat, how long until really cold air is coming from the vent? Well until then it's not a very efficient cooling machine, yet its drawing power.
If you can get rid of that start up inefficiency, that alone will lower energy consumption. One way to do that is have a thermal mass that will accept the cooling and absorb heat over time making the on and off cycles much longer, short cycling causes premature wear and is inefficient.
But your going to find I believe efficiencies are going to be close, there is no game changing design, least not yet, but a well designed matched system will achieve better efficiency that one mis-matched of course, and picking the good parts runs up cost, nothing is free.
The biggest difference will be in insulation, near perfect insulation would cut energy consumption to almost nothing and you would only need a small system too, win both ways.

Look at the Military unit above, it is 12" to 18" of insulation, that has to be a whole lot of the "secret"

[a64pilot]

Originally Posted by kmacdonald

A holding plate system is NOT more efficient. It's only advantage is being able to use excess energy, when available, to be stored in the holding plates for use when less energy is available. It is only suitable for a refrigerator and should never be used in a freezer.

Yes it can be more efficient by lengthening run times and off times, and to say a cold plate shouldn't be used in a freezer is incorrect. It would be correct if plain water was used in one, but a freezer plates solution will have a different freezing point, variable of course to the temperature your wanting to hold, a freezer plate and a fridge plate can be the same plate, just with a different solution.