Do you have a picture of the current setup of the fridge?

Sure thing...

It is still a proof of concept until I can find the mini-freezer of my dreams. Then I'll make it pretty.

But here are some photos, in all their hacked-together glory:

This photo shows the mini-Freezerator, with the new temperature controller sitting atop a special non-conductive T-shirt. Yes, there are hot wires out in the open, evidence of my casual relationship with lethal electricity.


Here is a close-up of the front, showing the new temperature controller, and the Kill-a-Watt that is faithfully still recording data.


It may be hard to see, but there is a wire running from the temperature controller to the temperature sensor, which is inside the Freezerator. The wire is going between the door-sealing strip. I did not modify the mini-freezer in any way, because I wanted to run this test, and I wanted to keep the possibility of re-selling the mini-freezer when I am done with the test.

As I have said before, it's looking like post-hack power consumption is about 50% of pre-hack power consumption. Therefore, to end up with a very, very low power refrigerator, you need to start with a very low power freezer.

This mini-freezer is a Summit, which is known to be a middle-to-low performer.

The mini-freezer of my dreams is a Haier HUM048EA 4.8 Cubic Feet Compact Freezer. It has thicker insulation, uses less power, and has a built in drain tube, which is important.


You can see the nice thick insulation in the photo. As I reported previously, frozen food packaging seems to be "modularized" into sizes that are different from regular food, which presents some interesting moments when storing food. As I mentioned before, the internal shelves are NOT reconfigurable, as they are, in fact the evaporator coils.

Door storage is also a challenge. Since I don't yet have a Haier HUM048EA to hack, I'm not sure of the approach that is needed. Worst case would be to completely rebuild the formed-plastic storage structure. However, it might be possible to modify the existing door structure.

There are also to be found, used upright mini-freezers that have external coils on the back. External coils favor efficiency, so one of these could make an excellent candidate.

As far as I know, all currently manufactured mini-freezers have coils that are integrated into the body.

Best,

-AC

Thank you! :thumbup:

I gotta get me one of those temp controllers. They seem to work good and are reliable.

So far... I have my fingers crossed.

I checked out the board that the controller has, and there's a small electro-mechanical relay, which is rated well above Freezerator loads.

But I am mistrustful of relays, and it's good to know that the signal that will drive a relay will drive a Solid State Relay.

ebay has scads of perfectly good 10, 20, 30 and 40 amp (and larger) SSRs for very reasonable prices. But again, there are also perfectly serviceable SSRs that are lower amps (2X freezer load ought to do it) cheaper, and even better, smaller.

-AC

How much power does the freezerator use compared to your old fridge?

Well, that depends on how far back in history we want to go.

This is a page from my notebook on refrigerator comparison


The red line shows my current Freezerator.

However, if you look at the line below it, you will see the Frostman refrigerator, which was smaller (2.6 cu feet, as I recall) and had external condenser coils on the back (very good design), and was somewhat cheaper to operate than the Freezerator.

But even for a fevered-brain, hack obsessed bachelor such as myself, it was too small to support even my minimized notion of civilized life.

So I opted for a "4-ish" cubic foot model, and finding nothing that came even close to the Frostman, in a refrigerator, or an all-refrigerator, I decided to go out on a limb and try the Freezerator hack.

But to give an answer your question that relates to the the realm of normal sized refrigerators, that sane people use, my refrigerator prior to the Frostman was a much beloved 1930's era refrigerator similar to this photo:


Note how thick the insulation on this puppy. It was a surprisingly efficient unit and as I recall, it was measuring in the range of 1200 watts/day. I was able to bring it back to life after its mechanical heart stopped on two different occasions.

By the way, just to give you an idea of my idea of a refrigerator, my refrigerator before that was like this one (probably from the 20s)...


I treated her really good too, but as with all mechanical devices, she had a heavy date with the salvage yard, that despite all my loving care, she was ultimately destined to meet.

R.I.P.


Best,

-AC

AC,

Where do you keep finding all these relics? All the killer antiques in my area are on the order of Rick Dale prices if they work. If not, they are either garage/yard ornaments or just outrageously priced or both. I guess the rednecks know what they have and then some.

They were built to last, and I thought often about the fact that I was using a refrigerator that could have been bought by my grandparents when they were younger.

Those old units (one refrigerator repairman called them 'Old Girls'), the very first ones came out when electricity was new and expensive, so to attract buyers, the units had to be very economical. Later, when the electricity rates were falling and power companies main problem was selling more electricity, the units became much less efficient, like the 'round top' units.


But the Old Girls were in use before DuPont chemicals had the brainstorm to make a synthetic, patentable refrigerant. The Old Girls used an organic refrigerant, often sulfur dioxide. To my knowledge, there is no one left who is able to service a sulfur dioxide refrigerator.

The compressors in those things lasts a very long time. The part that most often goes out is the motor starter. Motor starters made for modern refrigerators are cheap and will work on the Old Girls. I was able to successfully keep my Old Girls going by replacing the motor starter, and I was able to get another 15 years from each one.

A yard ornament won't work out, but a garage ornament... now that is a whole other story!

If you really have a liking for the 'Old Girls', just keep your eye open, and they will come to you.

By far, my favorite Old Girl is the Monitor top. I had one proudly in my kitchen for many years, just like this one:


I mean, putting the compressor on the top, and letting the heat rise, away from the refrigerator... what a concept!

Best,

-AC

Daox,

I saw your summation HERE, you did a nice job.

Thanks,

-AC

From the blog, Mark asks:

I think it's pretty much THIS ONE.

You should be able to find the specs yourself.

There is absolutely nothing about this unit that makes it a very good candidate for a Freezerator conversion.

In fact it has very little going for it. The efficiency is not so hot and it does not have a built in defrost drain. The reason I got it is that on the day I was looking, I found it for $90 on Craig's List, and I could continue my experiment.

What I learned is that even a very poor performing freezer makes a very acceptable Freezerator... with certain reservations.

Whatever candidate you choose should have a built in defrost drain, because the Freezerator will run very humid, which is great for produce. But there is a constant drivel of condensation, and a defrost drain will let you easily direct the condensation.

Also pick one that has really good performance specs, because your new performance will be better than twice as good.

My ebay temperature controller works well, but my Arduino controller was better.

So, there you have it... Go forth and hack!

-AC

Thanks AC.

For those interested, here is the link to the Summit freezer:

FS60M | Summit Appliance

Here is the energy star tag for the freezer. It is supposed to use approximately 879 Wh/day. Using it has a fridge uses less than half the power (395 Wh/day).

http://ecorenovator.org/forum/attach...1&d=1390400735

Yep, that's the one. Really a badly designed freezer.

But it brilliantly illustrates the Freezerator principle of increasing efficiency by running a freezer at refrigerator temperatures.

If the deplorable summit can come in as a winner, just think what a well designed unit would do!

-AC

So how is the freezerator doing? Did you leave the chinese controller rigged to it? If so, has it given you any trouble?

I decided to get another Uno clone for my next creation. The main reason being is flexibility. I'm just not exactly sure what this new unit will end up like. http://i.ebayimg.com/00/s/NDAwWDUwMA...TIeCR/$_12.JPG

Grand total of $21.99, shipped in 3 days. Ebay seller is 16hertzelectronics. I couldn't resist the shwag package. I believe you can never have enough jumper wires.

I also got some more dallas temp sensors just like your pic. 5 pcs DS18B20 1 meter waterproof. $11.99 shipped, got here in 2 days.

I believe I will be assuming command of a 9000 btu portable a/c unit like the one you got for free. I wish there was a way to pull the code from the micros in these little units. It would make decoding things like switches and display drive components SO much easier.

The Freezerator is doing just great. The temperature controller is still cranking along just fine, no problem with the Chinese unit. The current from starting the little freezer compressor is not so much. The relay seems to be holding up just fine.

We had a power outage about 3 months ago, back in March, so my Kill-a-Watt zeroed out then.

The duration of measurement is now 2185 hours.

The Power used is 26.34 kW-h.

This makes out to be about 12.06 watts per hour, or about 289.32 watt-hours per day.

Here is a photo of my freezerator, exactly as it is in use today:


You can clearly see that it is heaped up with crusty bachelor debris. I include this photo, because the top of the unit is actually one of the condenser surfaces, and if all this crap was not there, the efficiency would be even better.

But 289.32 watt-hours per day is pretty good for a pretty inefficient freezer, that is being badly treated. Starting with a better freezer, and keeping the top and sides, and back clear would yield even better results. But this hummer is only costing me $11.62 per year to run, so I'm not too motivated.

However, as I have previously posted, condensation needs to be addressed. With a regular refrig or freezer the humidity freezes, which dries out the food, but also prevents condensation problems.

With the Freezerator, the humidity doesn't freeze, it drips... which has the benefit of keeping produce in good shape for a much longer period of time that usual.

But the condensation has to go somewhere. I have tried a drip tray, which helped fairly well, but it isn't entirely satisfactory.

The best solution is a drain tube at the lowest point on the bottom of the inside of the Freezerator, that can drain into a reservoir or better yet, outside.

The volume of the condensation isn't much, maybe a half or a quarter of a teaspoon a day (maybe even less)... but it is relentless.

If you're gonna build one of these things (I highly recommend it), build in the drain tube before you ever start it up, because after you start using it, it is a major hassle to remove the food, dry it out and make the mod.


The Arduino temperature controller (Teensy in my case) is much better because you can dial in your hysteresis exactly like you want it. The Chinese temp controller I got is in Centigrade, so the degree intervals are larger, and therefore the temp swings are a bit too big to really hit the sweet spot.

It is quite useful to be able to log temperature swings, because that really helps in fine tuning the beast.

So:

• Freezerator good
• Arduino (or equiv) good
• 1-wire temp sensor good
• Solid State Relay good
• Condensation drain tube very good

Best of luck & take many photos,

-AC

The little fridges are very inefficient for their size, you have done well on the little freezer mod / hack.

My 21 cu. ft insulated fridge has been on the kill a watt meter for 2,221 hrs. in the process it used 85.60 kwh.

Which converts to 20.3 kwh per 5 cu ft. in the 2221 hrs.

I'm afraid that I don't understand what your calculations imply.

Could you explain?

-AC

Math says the insulated 21 cu. ft fridge is 24% more efficient by the cu. ft

Your freezer hack gave you nice gains , I imagine insulation would further the reduction.

OK, I understand that part.

So, how can this fact be beneficial to you in your real-world life?

That is the part that I do not understand?

-AC

I was not implying anything other then what the numbers denote ?

What ever you do DO NOT ADD INSULATION TO YOUR FRIDGE - I REPEAT DO NOT

You don't want helpful advice - YOU GET NONE ya grumpy mf lol

I wish your insights were as useful as you imagine them to be.

-AC

Please explain. Are you talking about adding insulation to a fridge with coils that would be insulated or are you saying not to add insulation inside the fridge? I'm looking to do the latter because I don't need as much cubic footage, I have the spare insulation, and there's no room for insulation on the top, bottom, or sides unless I put the insulation inside the refrigerator.

I realize that you are addressing your question to ecomoder, but I think that adding insulation to an existing refrig will result in only marginal improvement.

However if you gave up on your present fridge, and did a Freezerator conversion, your energy use would be cut in half, or even better.

-AC

I understand what you are saying but if I want both a refrigerator and a freezer in my kitchen without taking up additional space in the kitchen, adding insulation to a fridge/freezer combo unit seems to be the best route to go about it. By putting the insulation inside the fridge, I reduce the volume of air that is lost from when the refrigerator is opened along with being able to reach a higher R value than I otherwise can by putting it all on the outside. Depending on how much spare insulation I have left over I'll be putting some on the back and top as well, I just don't have room on the sides and the design of my fridge doesn't allow for any under the refrigerator.

OK, so on with the project!

-AC

Freezerator Update...
 

The freezerator keeps chugging along.

It is still condensing frost on a continual basis, so there is no buildup.

Produce that is in the freezerator still lasts surprisingly longer than in conventional refrigerators.

I have purchased a, aluminum food service tray that is as long as the freezerator is wide. The front 'feet' of the freezerator are in the tray, and the rear 'feet' of the freezerator are shimmed to bring the freezerator to just slightly more forward than level. So, occasionally the condensation runs out of the door and into the aluminum tray and evaporates. I never see any build-up.

My Kill-a-Watt looses its memory from time to time, but this morning's reading was over a 90.35 hour run, and the Kill-a-Watt recorded 1.46 kW-h used during that time.

My local electricity rate is $0.11/kW-h.

This calculates to $15.57/per year.

All this from the least energy efficient mini-freezer on the market (previously well used), that was converted to a refrigerator with a $20 part.

Best,

-AC_Hacker

That is very good energy usage.
My 4.5 cu mini refrigerator uses 235 KHh a year and I had to shop around to find one that low.

I know what you mean.

The unit I chose was chosen on the basis that I found it on Craig's list, it was cheap, and my girlfriend could help with transportation.

I already knew that the model I chose was at the bottom of the heap, but my intention was to see what the percentage of improvement would be as compared to the a similar unit, designed to be used as a refrigerator.

The results went way beyond my expectations. I imagine that the percentage of improvement would hold for a more efficient mini-freezer, too.

And it would be even better if a chest-type freezer was used, but I know that with my deplorable life-style, many things, heavy things, would accumulate on top of the freezerator lid, and I'd have to deal with them when I was grumpy and hungry.

I'm very happy with the result.

-AC

As I understand it, one of the properties which made sulfur dioxide such a good refrigerant, was that it acts as an excellent lubricant in the compressor and miscibility problems with the compressor oil (probably mineral oil) were non-existent.

These old girls were built at a time when the market was not yet saturated by refrigerators, so companies were building units to sell to first time buyers. Later, in the 50s and beyond, during the hyped up drive to sell to consumers (and not just citizens), manufacturers increased the dimensions of the refrigerators (and especially the freezers for all those TV dinners) to accommodate new tastes and more storage. Another way to increase size, was to reduce the insulation thickness, thus the inside dimensions got larger without increasing the footprint.

I suppose the larger freezer capacity and the energy intensive defrosting that goes with it doesn't help matters either.

Then there's the strip heaters they added to the door mating surfaces to prevent condensation, plus the heaters used in the cabinet walls for the same type of issues, associated with poor insulation.

I think there were a lot of reasons why refrigerator / freezers went through such a long period of inefficiency (arguably continuing to this day). Production of junk is the industry standard when that industry is based on profit and growth.

Regardless, I think people should have an affordable alternative. I would like to produce one.

You did a great job with this freezerator, AC_Hacker! I think it demonstrates how simply modifications can make a huge difference. I'm curious, have you ever attempted to measure the evaporator temperature to get an idea what the delta T is?

Less than 0.4KwH per day is real good.
By comparison my modern 2013 Kenmore (full size up right, freezer on top) uses about 1kwh per day.
Energy star my arse.

The evaporator temperature is a moving target... do you mean peak-chill?

And what temp are you looking for to compare it to?

-AC

I'd say that the Freezerator hack has been a huge success.

I have mentioned this before, the Freezerator is in a perpetual defrost mode, and the inside is always damp. This turns out to be excellent for produce, because it never dries out. On the other hand, there is a drainage issue to contend with. My current configuration has not satisfactorily solved that issue... I sort of do a periodic mop of the interior. I noticed that top-loading freezers often have a drain hole in the bottom, which would b perfect for attaching a drain tube to. I've also seen mini freezers that have a self-defrost feature, which includes a drain tube.

-AC

I think where my curiosity peaks, is in trying to evaluate the performance of a cap tube system designed to operate at around 0 to 10 degrees F, which is never allowed to drop below freezing. So yes, I'm curious of what the lowest surface temperature the evaporator reaches, but I'd also be curious how much superheat is generated, or in other words, just how starved the evaporator is.

Don't get me wrong; I am impressed by how little energy a box of that size, with that little insulation, can use. I'm interested in doing a small refrigerator project from scratch sometime, and it is pretty apparent that the passive heat exchanger is the way to go (with moisture management).

Yours is the first freezerator I've seen which wasn't a chest type. I wonder though if they all share the characteristic of a starved evaporator. I would think the cap tube is too long, or too narrow. But then again, I don't have much experience there! I'm actually going outside in a few minutes to construct a tiny DC dehumidifier with one of those Chinese Coke can compressors! Going to try my hand with some cap tube.

Running a cap tube metered circuit is always a trade-off. With a shorter tube, the system capacity is increased. With a longer tube, the balance point dT is increased. A longer cap tube will take longer to reach a colder box temperature; a shorter cap tube will reach a less cold box temperature faster. So with this freezerator application, shortening the cap tube would give you a faster pulldown of cabinet temp and shorter run times of the compressor.

This all sounds great, right? The only downside is that you run the risk of flooding the evaporator.Once the dT maxes out, the evaporator saturates. The liquid refrigerant cannot all boil off, so a fraction passes through, due to an increase in suction pressure (vs. a longer cap tube) . If this liquid reaches the compressor, bad things happen.

Better to starve the evaporator than to flood it. All refrigeration compressors are classified by the back (suction) pressure they are designed to operate with. Most freezers use low back pressure compressors, which are designed to cool themselves without much mass flow of refrigerant. This is why they are relatively larger in size than their heat pump counterparts of equal capacity: the motor and compressor head have more iron to shed their heat through.

I really don't see that pull down is an issue. I mean the Freezerator is actually a freezer, which has ample cooling power, but you are asking the compressor to run until a higher target temp is reached, the result is it runs in cycles of much shorter duration. If it is not able to meet the temperature, it just keeps running continuously until target temp is reached... then back to business as usual.

The effort in making this thing ultra-minimum. the cost of a unit is the cost of a very cheap freezer plus $20. The cost of running this thing is astonishingly low.

It's actually the simplest, most effective hack I have ever tried.

Before you wear yourself out try to improve it, you really ought to try it out... you'd be amazed.

If you actually want to improve on this thing, improve on dealing with or eliminating condensation. That actually is a problem.


-AC

Oh no, I am a fan of the keep it simple stupid approach as well. Operating a low-temp fridgie unit in medium-temp range is brilliant. With the decreased temp difference between ambient and icebox chamber, everything about the unit performs better than originally designed.

Also, with mass-produced designs, thousands of man-hours of design, trial, and testing work has already been invested. Many models have generations of preceding units' work to stand on. Reliability and longevity is not usually a problem.

The only bad thing I can think of that can happen with keeping food in a cool wet environment such as one of these conversions is listeria.
It likes cool wet environments.
It can double its numbers every 36 hours at 39'F.
So the closer to freezing you can keep your conversion the better.

Pathogenic listeria is normally only harm full to young children, old people and the unborn.
Cooking it kills it and I don't believe it leaves behind any harmful toxins.

Thanks for that, I wasn't aware.

The temperature does cycle, and runs in the 38F - 40F range.

-AC