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TF/Vitrifrigo compressor fridge condenser fan CFM ratings
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nocreditnodebt
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PostPosted: Sat Oct 20, 2012 3:10 pm    Post subject: TF/Vitrifrigo compressor fridge condenser fan CFM ratings Reply with quote

I am trying to get an Idea of what the condenser fan size and ratings are on Truck Fridge TF-49/65, Indel/ Isotherm and Vitrifrigo compressor fridges members have retrofitted into their Westy's over the years. I imagine the fan's brands and ratings varied throughout the years as the manufacturers found different fans to buy in bulk.

I don't expect anyone to pull out their fridges and look, but perhaps some members have noticed and/or have photos they could check. Even if it is part numbers only I could find the ratings.

I recently purchased a Vitrifrigo c51is through Karl@WestyVentures and was pleasantly surprised to see a 120 MM fan attached by 3 screws to the condenser.
It also came with a 270 ohm resistor on the thermostat circuit to increase compressor speed from 2000 to 2500 rpm. All Danfoss bd35 compressors are capable of having their compressor speed vary from 2000 to 3500 rpm. The slowest speed which yields less than a 50% duty cycle is most efficient. Faster compressor speeds mean faster cool downs but higher amp consumption while the compressor is running. I would also be interested to know whether your fridge came with a resistor in the thermostat circuit.

After some research and converting cubic meters per hour to cubic feet per minute, my stock Costech D12A04lws 120mm Fan is rated at :

71.74 CFM
34.4 DB
0.242 Amps

It is a loud fan with a sleeve bearing.

IdahoSkier posted that he replaced his stock 92 mm fan rated at 38 cfm on his TF-65 with a 92mm 42 cfm fan rated at 15db and that it was attached to the condenser with Zip ties.

I am very happy with my Fridge's performance but I believe the fan speed might be overkill. I am currently running under a 33% duty cycle to keep the box temps under 38f at 75f ambient temperatures. This is with the resistor removed. Duty cycle was slightly under 25% with the resistor installed, but amp draw is higher with higher compressor speeds.

I have found a 120mm fan rated at:
54 CFM
22 DB
0.05 AMPS!

It is in the mail. I believe 54 CFM will be more than adequate to remove heat from the condenser, and at 1/5 the energy consumption perhaps equate to 1 to 2 less amp hours taken from the batteries over 24 hours and be significantly quieter.

An E mail back from Noctua says the minor compressor vibrations should not effect the fan's performance or longevity.

Perhaps this information can be of benefit to other members wishing to slightly reduce battery consumption and noise of their retrofitted compressor fridges.

Here is the ~20$ fan I will be installing:

http://www.noctua.at/main.php?show=productview&products_id=42&lng=en

Also, I found that a small 40mm fan placed in the freezer compartment significantly reduces box temps at the cost of freezer temps, But my Ice trays and gel ice packs are still rocks. With the fan on, I back off the thermostat and have much more consistent temperature readings throughout the whole fridge. With the fan unplugged some parts of the fridge box are 40f+ and some are 33f.

The interior fan I am currently using was removed from some failed electronic device. It is rated at 0.08 amps and 6.1 cfm and 25 db. This is more than the 120mm condenser fan I purchased!

I will be replacing this fan with a low draw 40 mm Sunon Maglev fan.
6.3 cfm
0.03 amps
18 db.

http://www.frozencpu.com/products/17240/fan-1070/S...g36c15s560

I do realize that these fans will produce some minor heat which must then be removed from the system, but I believe the benefit is greater than the detraction. It is also why I researched out the lowest consumption Fan I could.

I'll be posting back with pictures and performance reports next week.

Thanks for reading
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PostPosted: Sat Oct 20, 2012 7:01 pm    Post subject: Reply with quote

You rock. I'm eating this stuff up! I don't have time to do this kind of research.
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PostPosted: Sat Oct 20, 2012 7:27 pm    Post subject: Reply with quote

When I was looking at fans for my "city water" fan install on my '81, I was surprised at how low the draw could be for a relatively higher than expected CFM rating. Given my limited knowledge of them, this seemed like getting "something for nothing" but I guess computer case fan design has only improved over the years.

FWIW, this is the fan in my TF65

Searching the PN, I get this pdf: http://www.tmfan.com/doc/ball%20bearing/90size/DFB922512L.pdf

From that:

40.54 CFM
25.52 dB-a

Neil.


Image may have been reduced in size. Click image to view fullscreen.

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PostPosted: Sat Oct 20, 2012 8:48 pm    Post subject: Reply with quote

Thanks for the replies!

That makes two TF 65's with an ~ 40 cfm fan.

Interesting that a 2.3 cubic foot fridge is using a lower CFM condenser fan than my 1.8. Any idea if they used a resistor in the t-stat circuit on the TF 65 to increase compressor rpm? Does it draw ~ 3.3 amps(2500 rpm) or ~ 2.5 amps(2000 rpm)

1.6 watts at 12 volts = 0.13333 amps.

So that Fan in Neil's photo uses more than twice the amount of current to move less air, and at 3 more decibels than the Noctua NF-F12.

The Noctua's have high static pressure readings as they are really designed to have restriction in front of the fan rather than behind it, but the condensers probably do not have as much restriction as the radiators on high powered water cooled computers. Most fans have a real wide exit angle. These fans have a narrow beam ensuring more air bathes the compressor and controller.

Here is a picture of the resistor which came on my Vitrifrigo:
Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


Resistors can be soldered inline with the wire too.

Image may have been reduced in size. Click image to view fullscreen.


From the pictures I have seen of TF's the condensers are slightly different.
Image may have been reduced in size. Click image to view fullscreen.


I imagine a larger 120mm fan could be used even if the screw holes do not line up. I think My Noctua fan will arrive on Monday, Tuesday at the latest.
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PostPosted: Sat Oct 20, 2012 10:06 pm    Post subject: Reply with quote

Excellent info and research, thank you!
I'm glad you're showing the results of real-world testing that you've done because I'd take ALL of those claimed cfm's and decibel ratings with a large pinch of salt. Most cfm ratings are projected from design but if the numbers come from an actual test, they are done in free air, ie NO restriction front or back with the highest reading from various points, used.
Just as with any product, the manufacturers want to paint the prettiest face they can on their pig. Very Happy
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PostPosted: Sun Oct 21, 2012 12:45 am    Post subject: Reply with quote

I do take the CFM ratings and DBa claims with a grain of salt. I have more muffin fans than any sane person should admit to and am very conscious that the impeller and case designs make huge differences in airflow noise and current consumption. Some of the CFM ratings in comparison to other fans I own seem a little high( I have no way to measure), but all of the posted maximum current draws have been accurate according to my battery monitor. The claimed DB levels of all my fans seem accurate in comparison to one another, though the pitch makes some louder rated fans seem less annoying than others, and this no doubt varies human to human.

I don't think the fans which came with the fridges are inadequate, I just think they are not optimized for their task of removing heat from the whole condenser on a fridge designed to use very little battery power and match the quiet aspect and efficiency of the Danfoss compressor.


In the case of the Fan on my 1.8 cubic foot Vitrifrigo with a 2k rpm compressor speed, I think 71 CFM IS overkill, and the noise, even in my insulated, well ventilated fridge cabinet is a little disturbing, and knowing it is drawing 1/4 amp for 20 minutes every hour at my current duty cycle is also a little disturbing.

The Noctua fan's reviews have been most impressive, and the amp draw, according to several video reviews( of dozens) on U tube is indeed only 0.05 amps, and this electrical savings is significant.

The fact that the company's website is so thorough and they responded to my E mail within an hour was also impressive, and I ordered the fan the next day.

My Favorite fan up to this point has been the Silverstone FM 121. It is adjustable speed, variable from 31 to 110 CFM, <0.1 amps to 0.4 amps, 17 to 39DB and any point in between with the turn of a remotely mounted dial. I use 3 of them to keep my Van at or below ambient temperatures.

Do Note that the Danfoss compressors can only power a Fan consuming upto 0.5 amps. Any higher than this and the controller will assume the fan is failing and will shut off the compressor to prevent damage due to overheating. With the Low draw Noctua fan, one could even use the controller to power 2 fans. One for the condenser, one to evacuate the cooling unit compartment only when the compressor is running, and still use less electricity than the single stock supplied fan.

I have considered using this adjustable speed fan on my condenser to dial in an acceptable noise level and crank it higher when noise was not a factor and my solar was producing extra amps, but ultimately the current consumption of the Noctua NF-F12 cannot be beat.


I will be playing with the location of the internal 40mm fan some more. I found when it was on the floor blowing horizontally it did not do very much but even out the box rising box temps. When I put it in the freezer, box temps dropped to the low 30's and I had to dial back the T stat. I am going to try up top, outside the freezer blowing upwardly on the outside of it. I took the 12 volts from the light and have a quick connector on it, so no extra wires running inside or through the door. Each time I disconnect it, the interior temps rise and I need to crank up the dial a full hatchmark to keep the interior below 40, So I am sold on it's effectiveness.

For those interested in Varying Compressor speeds there are products designed to do so for the marine world who take their refrigeration very seriously.

http://www.veco-na.com/images/Compressor_Speed_Con....25.11.pdf

Danfoss also sells a controller which plugs into the compressor and adjusts speed automatically to load placed in the box.

http://www.rparts.com/documents/aeo_technical_info_06-03_ct31b102.pdf

I have toyed with the idea of an easily accessible 500 ohm potentiometer which would yield compressor rpm from 2000 to somewhere around 2800 rpm for quickly sucking the heat out of warm beer then dialing it back to the minimum for efficiency once that task was completed. A 1500 ohm Pot could take the compressor to 3500 rpm, but these speeds are for fridges 3 times the size of mine with larger evaporator plates.

Thanks for contributing to this thread.
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PostPosted: Sun Oct 21, 2012 7:39 pm    Post subject: Reply with quote

Well my friend, I think your next task is to put all the right pieces together in a box that fits the fridge space and market it! Very Happy
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PostPosted: Sun Oct 21, 2012 9:26 pm    Post subject: Reply with quote

I went into the bar the other day walked up to the Prettiest self declared Princess:
" Hey baby, bet my fridge is more quiet and efficient than anybody else's in here......"

The day that line gets me laid, is the day I think about going into the fridge making business. Laughing


Anybody else with a Danfoss powered TF,NovaKool/Tundra/Waeco/Dometic/Isotherm/ VitriFrigo care to take a gander at their condenser fans and also see if they have been provided a resistor in the thermostat circuit?

Not very interested in Norcold or Engel since they use passive condensers in the front loading versions. The chest versions probably have forced fan condensers, but access to see them is unlikely
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PostPosted: Tue Oct 23, 2012 12:46 pm    Post subject: Reply with quote

I just pulled the fan on my Vitrifrigo C51iSAC to see what it's rated at. It's an X-Fan model RDL1225S, rated at 0.18a, 28dBA and 70.18CFM (see: http://www.x-fan.jp/products/120.html).

These are pretty darned good specs (assuming they are accurate) that would be hard to substantially better with an aftermarket fan. The Noctua listed by the OP would definitely be an improvement in power and noise, but with a 1/3rd less CFM of air.

As it stands, the noise on the fridge is most definitely noticeable, so it would be nice to find something quieter (and more energy efficient to boot), but I'm apprehensive about losing airflow/cooling.
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PostPosted: Tue Oct 23, 2012 1:15 pm    Post subject: Reply with quote

P.S.... Time to put the fan back on - now which way was it pointing????
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PostPosted: Tue Oct 23, 2012 4:08 pm    Post subject: Reply with quote

Thanks for going through that effort.

The Fan sucks air through the condenser and blows air onto the compressor.

Interesting that Vitrifrigo has such higher CFM fans than truckfridge. Looks like your x fan is more impressive than my Costech

I just got my Noctua fan. Pretty impressive.

I'm about to hook it up. Will report back
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PostPosted: Tue Oct 23, 2012 6:51 pm    Post subject: Reply with quote

The Noctua Fan seems to be nicely built, Noticeable heavier than any other 120mm fan I own.

Once I figured out that yellow wire is the (+) I hooked it up to 12 volts.

There is a black/ green/ blue and yellow wires exiting the hub. Instead of the red/black/yellow I am used to.

In free air, The Noctua was not quite as quiet as expected, but moved the amount of air I expected, and in a narrow column.

Attaching it to the condenser, and it was noticeably quieter than the Original 71 cfm Costech, but not nearly as quiet as expected. The Costech in free air is fairly quiet itself, until I put some restriction behind the fan, then it got loud. The Costech vibrates a good amount on it's own too.

So I removed the Noctua while it was running, and as soon as the restriction was removed from behind it, it got quiet again.

Then I placed it on the other side of the condenser so it was pushing air into it, and it did not get any louder. Since I added 3/4" more insulation to the fridge itself, and 9/16" more to the cabinet itself, the fan will have a few inches to pull air in behind it, and i think I am going to leave it on this side.

The Noctua comes with a low noise adapter, which is just a 4 inch connector with a resistor one can put inline on the cord, and this knocks down the 54 cfm to 43.74 cfm, and with this in place, My ear has to be within 18 inches of the fan to hear it. I imagine it knocks down the marginal amp draw slightly too.

So now, some duty cycle tests. I know what to expect with a 71 cfm fan, I will check it at 54 cfm, and at ~44 cfm too.

Will report back.
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PostPosted: Tue Oct 23, 2012 10:10 pm    Post subject: Reply with quote

I took out the LNA adapter so the fan is running at full speed. 54 cfm and pushing air into the condenser.

Last 3 cycles were 4:45(+/- 0:10) ON and 14:50 (+/- 0:07) OFF with the interior at 34.5f. Ambient 68f.

I've never recorded above 12:35 off before, even in cooler ambient temps than current.

I am used to cycles being ~4:25 ON and 9 to 12 minutes OFF.



So far, it appears the lower CFM fan is not negatively effecting duty cycle. If anything it is reduced.

The compressor is running ~30 seconds longer when it is on, but then is staying off longer too, by 2+ minutes, for which I have no theory.

It is out of my cabinet at the moment, But the cabinet is well ventilated, and extra insulation touches the sides and bottom when it is in the cabinet, so it should perform slightly better in the cabinet.

After the compressor turned back on this last cycle, I opened the door too temp readings with my IR thermometer, and dialed back the t stat a few degrees, and it shut off after:
....... 3:15 ON, then 11:35 OFF
Then 4:50 ON, then 16:20 OFF
Then 4:10 ON,


I.m gonna put it back in the cabinet now.
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PostPosted: Wed Oct 24, 2012 2:02 am    Post subject: Reply with quote

The Fan Noise with the fridge installed back in the cabinet is not as quiet as hoped. Quieter than stock, but still noticeable. It is more pleasant though, A soft whoosh instead of an irritating whirrrr.

The Duty cycle has remained impressively low. The Ambient temperatures are dropping, Now to about 60f, but the ON cycles have consistently been 4:30 to 4:50 ON to 15:50 to 19:55 OFF since last post. The OFF cycle duration is curiously longer for which I have no explanation. The ambient temps cannot explain it as they were the same at the beginning of my test and are still much longer than similar temps with the old fan.

It makes no sense. If the Noctua fan is that much better at pushing air through the condenser than the old faster fan pulling the air, then I would expect shorter ON cycles and the same duration OFF cycles

I am now at 2 of 7 on the thermostat dial. The interior temp is now 37.5 degrees. Some really low frequency harmonics which were bothering me with the old fan are now gone, but I did add some soundproofing measures to the cabinet and cannot attribute it all to the fan.

I inadvertently added some restriction to the fan's intake path which I will re engineer and eliminate tomorrow, but so far, I am amazed at the sub 25% Duty cycle and confused by these impressive, and unexpected results.

I Don't know when/if I will try out the Low noise adapter and ~ 43 cfm

Latest Cycle:
5:13 ON, 25:30 OFF. 58 ambient 38 interior
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PostPosted: Wed Oct 24, 2012 7:23 am    Post subject: Reply with quote

hmmmm - I wonder if I should move the stock fan to the other side and see if it improves the noise....
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PostPosted: Wed Oct 24, 2012 10:59 am    Post subject: Reply with quote

The closer I placed a flat board to the fan's intake the louder it got. If your fridge cabinet walls are not at least 2.5 inches away from the fan, or the vent is not directly behind the fan then I do not think it will improve the noise. If i did not have extra ~1.5 inches of insulation, then the fan would be too close to the cabinet wall

A couple questions CCC, do you have the resistor on the t stat circuit?
Was your fan connected on 3 of the four corners vie screws, like mine?

One fan corner was so close to copper tubing they didn't bother with a screw on mine. Now that it is on the other side I can use 4 screws. They are stainless steel BTW.

Were you not able to read the fan's label from the sides while it was still installed on the condenser?

I had to use Needle nose vice grips on one screw head to extract it, and probably would not have gone through the effort just to satisfy some lunatic's request on the internet.

If you do move the fan to the other side, be wary of putting a screw into the copper piping of the condenser. Mine bottomed out a few mm away from the pipes but it was nerve racking.

I noted one more cycle last night of 4:45 ON and 24:50 OFF before sleep got the better of me. Box temps this morning had risen to 38f.

This morning:
5:46 ON/21:52 OFF, just turned dial up slightly. 38.5 f interior, 67f ambient.
6:27 ON/
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PostPosted: Wed Oct 24, 2012 12:48 pm    Post subject: Reply with quote

Okay this will likely be my last duty cycle report, as the results are too consistent.

The ambient temps have increased to the mid 70's, the interior temps have dropped back down to 36.5f with the increased t stat setting, and the duty cycle remains 25% or under.

I keep looking for fault, but with stopwatch at my side and an IR thermometer taking interior and exterior readings every cycle, everything is consistent.

Duty cycle remains improved, noise is down, and the fan itself draws nearly .2 amps less than it's predecessor.

Here's how it looked before returning it into the cabinet.


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PostPosted: Wed Oct 24, 2012 7:15 pm    Post subject: Reply with quote

No resistor.

Three screws, just like yours.

I haven't insulated my fridge like you have.

I'm going to try moving the fan, when I have some time....
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PostPosted: Wed Oct 24, 2012 8:01 pm    Post subject: Reply with quote

Thanks again. Did you remove a resistor, or did it not come with one?

How old is your fridge?

3 hours ago, I added a gallon of 42 degree milk and 2.5 pounds of 43f Turkey to the interior. They are now 38.5 degrees, and the duty cycle has progressively lowered into just slightly over 25% with 68f ambients.

I don't feel there is any risk in going to a lower CFM fan. Perhaps it makes a Difference in initial cool down, but my performance has increased with the lower CFM Noctua fan pushing air.

I know of a 2.2 cubic foot danfoss powered Tundra with a 92mm fan mounted diagonally across the condenser. It too is likely ~40 cfm.

So that makes 3 fridges larger than ours with smaller sized, lower CFM fans.

If you really do not want to lose CFM, you can find quieter rated fans that move just as much air or more, for less amperage, if the ratings can be believed.

http://www.silenx.com/quiet.fans.asp?sku=efx-12-15

.11 amps, 74 cfm, 15 db. But no static pressure figure.

There are variable speed fans too:
http://www.silverstonetek.com/product.php?pid=118&area=en

It's lowest speed is 33 cfm. I sleep with one of these at my head as an intake fan on low. I bet within a cabinet this would be inaudible on low. 110 cfm is likely very overkill in any condition on a fridge.

Other variable speed fans exist too which only go upto ~74 cfm.

Edit: My 120mm Costech fan, that came with my Vitrifrigo, rated at .24 amps......I tested it's current consumption with my multimeter. It was listed at .24 amps. Well it pulled .24 amps, for less than a second, then used 0.1 amps to hold full speed.

I wonder how many fan ratings out there list the inrush current rather than the running at full speed current.

My interior 40 mm fan 4.9 cfm fan, pulls 0.07 amps.

I removed some restriction from behind the Noctua fan and the whooshing sound has lessened by about 25%
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PostPosted: Fri Nov 02, 2012 11:13 pm    Post subject: Reply with quote

I have one more report of a 40 CFM, 92mm condenser fan, on a 2.2 cubic foot Tundra fridge that DOES have a resistor inline to increase compressor speed.

My fridge is still running under a 33% duty cycle in temps up to 85f, and drops down to around 12% in mid 50's ambient temps.

I did a couple more modifications so that the air moved by the condenser fan has nowhere to go but outside the van. The new Noctua condenser Fan sucks cold air from the floor then pushes it through the condenser and through my cooling unit tunnel, and exhausts it out the vehicle with no chance to be recycled through the condenser. I can feel the warmed air when I stick my hand near the vent on the exterior. I do want to recycle this air into the interior in colder temperatures, but that modification will come later when I have designed a better method for doing so.

With the several reports of 40 cfm condenser fans I feel I could add the low noise adapter/ inline resistor provided with the Noctua fan and have more than adequate airflow (43CFM) through the condenser. The Noctua fan has higher Static pressure stats than fans rated at twice its airflow, and I feel it will outperform any 92 mm fan sucking air through only a portion of the condenser, and at a fraction of the current draw, and noise.

I ordered a new interior fridge fan and received it yesterday. I removed the previous worn 40x10mm Delta fan last night with the box temps at 36.5f degrees, but did not install the new fan until today. In the morning, the average box temp had risen to 42.5f degrees without touching the thermostat dial! That is in mid to high 50's overnight ambients and without opening the door for 8 hours! I always take a number of readings with my IR gun floor, left wall, right wall and back, and average them out.

While the fan itself is a minor heat source, I feel it only adds to the fridge performance. There is no doubt it helps cool down contents faster, and evens out internal temperatures significantly, according to my IR thermometer.

The owner of the Tundra fridge has taken A/H readings over 24 hours and found his 50 mm 18 cfm fan increased the amp consumption by 1 a/h over 24 hours compared to no fan. This does not include the amp draw of the fan itself, he claims. I think he was also doing the tests with an empty fridge. My tests have always been with a loaded fridge.

Here is the interior fan I just installed.
http://www.frozencpu.com/products/17240/fan-1070/S...g36c15s560

It only draws 0.03 amps and moves 6.3 CFM. It is the lowest draw fan I could find. I don't think any higher CFM rating would be beneficial. Higher CFM would probably just generate more heat, and push out more cold air when the door is opened.

It is very quiet. My other fans I could hear outside the fridge, this new fan I cannot. It is barely audible with the door open. Hopefully it stays quiet.

Right now I have the 40mm fan placed in the freezer. I am thinking of moving it behind the dial blowing on the exterior of the freezer. The warmest spot in the fridge is the area in back under where the cooling unit resides on the exterior. I think the fan exterior to the freezer will even out the interior temperatures even more.
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