pianotuna
Regina, SK, Canada
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SJ-Chris wrote: Question: What does "in a mask" mean? Thanks!
-Chris
Think of a floor fan. There is nothing other than the grill work.
Now put that fan in a wall. The wall acts as a mask.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.
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stripit
Prescott
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When we full timed in a Mobile Suites 5th wheel I installed 2 fans, one at the bottom area and one up top at the factory installed vent. This way I was sucking hot air and helping it extract out the top. We found before that if we were parked where the kitchen/refridge side was exposed to the direct sunlight and it got hot, the fridge was not able to keep the correct temps. I could remove the fridge exterior acess panel and either plug in or unplug as the need arose. I bought 2 square box fans about 4 inches across and they fit very well and had no noise we could ever hear.
Stacey Frank
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SJ-Chris
San Jose, Ca
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pianotuna wrote:SJ-Chris wrote:Does anyone have any "before and after" data points or personal observations after having added such a fan?
Thanks!
Chris
Yes.
Cool down from ambient without fans 4.5 hours to first cycle
Cool down from ambient with fans 3 hours to first cycle.
My twin computer fans are in a mask at the top of the chimney. They are thermostatically controlled.
This limits air flow in colder weather.
I do have a thermocube and a 40 watt bulb for freezing temperatures.
pianotuna (and others with fans): What temperature settings do you have on your fan thermostat? What does the ambient outside temperature need to be before your refrigerator vent fan actually turns on? Does the fan only turn on on hot days? Warm days? Or even on cool days?
I would like to understand better what the NORMALtemps are behind the refrigerator while in operation. I assume it is somewhat (or heavily??) dependent on the outside daytime temperature. Say for example on a 70 or 80 degree F afternoon, what temperature does the space behind the refrigerator get? Is it just slightly warmer than outside ambient air temperature? Or is it 20, 30, 50 or more degrees hotter than outside ambient air temperature? I'm trying to understand what the temperature difference is between ambient outside temps and the temp behind the refrigerator. I suppose if the temperature behind the refrigerator gets 40 or 50 degrees hotter than outside ambient air temperatures then blowing in more outside air will definitely help cool that air behind the refrigerator significantly and make a fan worthwhile.
Is there any downside to the refrigerator's operation that could happen by adding a fan to help cool behind the refrigerator? Is it possible to blow TOO MUCH air across the cooling unit and out the top vent? I see some inexpensive fan/blowers online that push ~45CMF. This could be mounted to the side exterior vent and blow up the back of the refrigerator towards the roof vent.
-Chris
* This post was
edited 10/22/22 01:39pm by SJ-Chris *
San Jose, CA
Own two 2015 Thor Majestic 28a Class C RVs
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JaxDad
Greater Toronto Area
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I added a rooftop self-powered vent fan to the top of my C many moons ago, it uses no power and is nearly silent.
They are often used on tradesman’s vans, especially ones that carry anything flammable (torches, liquids, etc) in the back. You’ve probably seen one and just didn’t realize what it was, they look like a child’s spinning top. The principle is, as you drive, or even a light breeze blows, the exposed spinning top turns, this in turn spins a smaller fan down below the roof which forces air up and out through the top spinner.
It works very well, and uses zero electricity.
https://www.flettner.co.uk/van-roof-vents/
Not the same make as the one I used, but the first example I found of a similar product.
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pianotuna
Regina, SK, Canada
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SJ-Chris wrote: I would like to understand better what the NORMALtemps are behind the refrigerator while in operation. I assume it is somewhat (or heavily??) dependent on the outside daytime temperature.
-Chris
If I remember correctly the operating temperature may be up to 700 F. (and no that is not a typo). I think I read this at a site that shuts down the unit when it hits about 350 F.
I set my thermostat at 80 f.
"The refrigerator uses three substances: ammonia, hydrogen gas, and water. The cycle is closed, with all hydrogen, water and ammonia collected and endlessly reused. The system is pressurized to the pressure where the boiling point of ammonia is higher than the temperature of the condenser coil (the coil which transfers heat to the air outside the refrigerator, by being hotter than the outside air.) This pressure is typically 14–16 standard atmospheres (1,400–1,600 kPa) at which pressure the dew point of ammonia will be about 35 °C (95 °F)."
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Blazing Zippers
North Idaho
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I glued two 120mm fans to the inside of the black plastic refer grill. They are at an angle so the fans blow upward. I placed a small switch on the outside of the grill to turn the fans off/on.
I have noticed an improvement in the refer temps.
I had one fan, the switch, and had to buy one fan for $13.00.
The best part of this story is that I did not have to go to ER while doing this mod!!
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SJ-Chris
San Jose, Ca
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Blazing Zippers wrote:
The best part of this story is that I did not have to go to ER while doing this mod!!
LOL....that's always a good start!
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austinjenna
Columbus, Ohio
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Quote:The best part of this story is that I did not have to go to ER while doing this mod!!
Then you must have been doing it wrong. Please disassemble and try again.
2010 F350 CC Lariat 4x4 Short Bed
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2112
Texas
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Quote:What temperature settings do you have on your fan thermostat? My factory installed thermal switch attached to the upper cooling fin is set at 130°F.
That switch failed open so I bypassed it with a manual toggle switch inside the lower side cover so I can manually turn the fans on when needed.
Running the two factory installed fans during the hot Texas summer makes a huge difference.
My fridge is mounted in a slide out so the fans are required for proper cooling in summer
2011 Ford F-150 EcoBoost SuperCab Max Tow, 2084# Payload, 11,300# Tow,
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SJ-Chris
San Jose, Ca
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pianotuna wrote:SJ-Chris wrote: I would like to understand better what the NORMALtemps are behind the refrigerator while in operation. I assume it is somewhat (or heavily??) dependent on the outside daytime temperature.
-Chris
If I remember correctly the operating temperature may be up to 700 F. (and no that is not a typo). I think I read this at a site that shuts down the unit when it hits about 350 F.
I set my thermostat at 80 f.
"The refrigerator uses three substances: ammonia, hydrogen gas, and water. The cycle is closed, with all hydrogen, water and ammonia collected and endlessly reused. The system is pressurized to the pressure where the boiling point of ammonia is higher than the temperature of the condenser coil (the coil which transfers heat to the air outside the refrigerator, by being hotter than the outside air.) This pressure is typically 14–16 standard atmospheres (1,400–1,600 kPa) at which pressure the dew point of ammonia will be about 35 °C (95 °F)."
I have seen a few different websites mention that the BOILER (which is inside the "chimney" and has insulation around it) operates at around 180*C (which would be about 356*F). But that heat would be contained inside the boiler. Then all the "hot liquid" (...sorry, just using generic terms here) flows through the system, coils, etc and eventually cools. I know that all those coils behind the fridge get warm and/or very hot. This will all create heat behind the refrigerator itself (inside the space where the refrigerator is mounted). I have a roof vent, so the hot air will rise and go out the roof vent, and pull in air at the bottom (at whatever the air temperature is outside).
I'm wondering if anyone knows approximately what sort of temperature this air behind the refrigerator gets during normal operation on say an 80*F afternoon. Is it 100*F? 150*F? I don't imagine it could be hotter than that.
Seeing as how the operation of the system is that the "hot liquid" flowing through these coils needs to cool back down as it flows through these coils, I can certainly see how pushing out, for example, 130*F air and replacing it (from the fan blowing it in at a much more significant rate than with no fan) with 80-90*F air will HELP the liquid cool much easier/faster/lower-temp and thus the refrigerator can have a much easier job (and likely cool the interior of the refrigerator/freezer significantly).
Since I enjoy these sorts of projects/experiments, I think I'll move forward with this project on one of my Class C RVs and when I do I'll be sure to report back with before/after comparisons and data. Will likely take me several weeks as I'm busy with other things at the moment. And I think the best test/comparison will happen when temps are back up to 90*F or more.
-Chris
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