Fridge air circulation.

[HTF]

I have a 80L compressor fridge from Thetford and a 25L compressor chest cooler I use as freezer. The freezer will go down -20ºC on the thermostat but I feel the the frozen goods, although frozen, they are not at -20ºC. I have to remove the individual ice cream popsicles from the cardboard box for example and still, they don't freeze very hard. The fridge also, if I ramp up the thermostat, things will get colder near the back wall of the refrigerator and ice will start to form freezing stuff that's only superposed to be cold.

Has anybody experimented with forced air circulation? I was thinking about making some 3D printed diffusers attached to a small radial fan to move the air around to give all the air inside opportunity to cool. Is this a crazy idea?

 

[saxonborg]

Can’t remember where but I have definitely seen somebody fit a small fan in the refrigerator to improve circulation, more than likely it was on YTube.

 

[wildebus]

I would first empty the freezer and see what temperature the freezer is actually going down to. If an empty freezer only goes down to say -15C, moving the air in it won't make it lower.
sounds like the temp is nowhere near -20C if Ice lollies are not frozen hard.

When it comes to the Fridge/Freezer, the control is generally useless. To get the freezer to the coldest temp, you often end up with ice in the fridge so becomes a matter of compromise. I have my freezer running at -17C which is as low as I can go while having the fridge not going too cold.

You can get very handy and inexpensive temperature loggers to see what is going on - here is a link to a 2-pack set https://amzn.to/3Fw0wUm - you could use one in the chest cooler and one in the Thetford.

 

[HTF]

I'm not worried about the micro freeze compartment of the main fridge. The fridge has a 5 step touch power setting that will cool the contents very well if set to 4 or 5. The problem is that with a full fridge, the cooling is not very well distributed and there is much more ice build up next to the little evaporator section at the back right below the freezer compartment and over the drain channel. The goods touching that area will try to freeze. The fan would help move the cold air around to distribute it better. Many household fridges now come with circulation fans.

The same with the horizontal cooler box that works as a cooler or deep freeze (mode I use) depending on the digital temperature setting. The side wall where the evaporator coil is located will reach the temperature but the area compared with the volume is small. I imagine that blowing "hotter" air over this area from the opposite corner of the box would help to distribute the cold. I'm going to try as I don't have much to lose.

 

[trevskoda]

I tested my we table top with a fridge temp unit and it had no bother to hit -20c freezing and +2 main fridge, there are no vents on mine and it is a sealed unit.
But i put 2 up top to keep air around it and the van wood either side.

 

[Landyseverywhere]

We had an LG compressor cool box that we used as a freezer set at minus 18 c never had a problem made no difference ful 1/2 full or near empty.We now have a 240v Russell Hobbs fridge with separate freezer I put a £5 Chinese temp controllerl to override the built in mechanical stat I fitted the probe in the (separate) freezer set to mine -18 max -13 to prevent rapid cycling it works perfectly keeps the fridge around+4.I use the same set up on a home fridge freezer that used to need a new mechanical stat every couple of years.Also use one on the van water heater

 

[Geek]

My motorhome fridge (proper 3-way sort) has three vent fans on the outside and a small circulating fan on the inside. Works brilliantly in any weather. Really steady temperatures and no problems. The fan is in the fridge, but it seems to make the freezer work better too.

The mains fridge in one house has a built-in internal fan, which is audible (stops when you open the door) and the temperature seems stable to quite a tight tolerance between 2 and 4 degrees.

The mains fridge (about twice the size) at the other house has no internal fan and it's impossible to get right. The temperature varies from over 9 to below freezing. Ruins salad!

I do wonder if it is a faulty thermostat, but I'm planning to fit a small usb fan inside it to see if better circulation will improve things.

I'll try to remember to report how it goes when I'm over there next week.

 

[trevskoda]

My motorhome fridge (proper 3-way sort)

Think you meen from the stoneage.

 

[Geek]

Think you meen from the stoneage.

Absolutely not! All the proper high-end (not bling) motorhomes still have 3-way.

Compressor fridges are a fashion fad, like halogen spotlights. And they do have some advantages. I have to turn my fridge off for the chunnel.

I don't want to spend my life obsessing about voltages and charging.

If my fridge (which is now in its 27th year) was to expire, I'd look for a replacement of the same sort, hopefully a second-hand one from someone downgrading to a compressor.

 

[trevskoda]

Absolutely not! All the proper high-end (not bling) motorhomes still have 3-way.

Compressor fridges are a fashion fad, like halogen spotlights. And they do have some advantages. I have to turn my fridge off for the chunnel.

I don't want to spend my life obsessing about voltages and charging.

If my fridge (which is now in its 27th year) was to expire, I'd look for a replacement of the same sort, hopefully a second-hand one from someone downgrading to a compressor.

The titanic used them lol, any i have stripped out of old caravans have been troublesom and very rusty, im told they dont work well in very hot places, and they are very expensive plus require electric fans to help them work well, but to each there own, im sticking with electric.

 

[Geek]

Er, no. The Titanic used compressor fridges.

Yes, I'm told three way fridges don't work very well in hot places, and unless fitted properly, they don't.

However, when they are properly fitted - and yes, with fans, they work extremely well.

Mine happily keeps the freezer at -20 and the fridge at 3 in ambient temperatures of 38. In fact there's more of an issue when it is cold. If the ambient temperature is cool, the fridge stays at 3 more easily, which can cause the freezer to warm up to -15 at times. And yes, I have a temperature display for both so I know that to be the case.

Perhaps when it gets old it will be less good. It's only 26.5 years old so far.

The amount of power used by the four fans (mine has three on the top vent, one inside) is less than 1.5 watts.

 

[Pudsey Bear]

I have a 80L compressor fridge from Thetford and a 25L compressor chest cooler I use as freezer. The freezer will go down -20ºC on the thermostat but I feel the the frozen goods, although frozen, they are not at -20ºC. I have to remove the individual ice cream popsicles from the cardboard box for example and still, they don't freeze very hard. The fridge also, if I ramp up the thermostat, things will get colder near the back wall of the refrigerator and ice will start to form freezing stuff that's only superposed to be cold.

Has anybody experimented with forced air circulation? I was thinking about making some 3D printed diffusers attached to a small radial fan to move the air around to give all the air inside opportunity to cool. Is this a crazy idea?

I fitted a PC fan to my self build, cable tied to the fins, power came in via the drain slot in the back, it did seem to work when tested with an IR gun, down side is for it to work you need space around the food for the air circulation