FRIDGES IN HOT WEATHER

Baz421 · Guru

FRIDGES IN HOT WEATHER

Whenarewethere · Guru

When I got my Waeco 28 litre fridge I did some tests for 3 days heating a bedroom with 3 heaters to 35C for 3 days. The lowest I could get the fridge was to -13C.

I think you might be pushing it to get the fridge to 48C below ambient temperature. If the fridge has dust around the compressor, poor & or low quality fan ventilation it is not going to help either.

When I did my extensive tests on the fridge with better fan & insulation, the fridge would not get any colder than 48C below ambient, it would only got a bit more efficient using less power.

We are probably all going to be at out cooling limit. The only thing you could do is fill it with thermal mass, lots of water in containers & run the fridge flat out over night so the fridge has the cold mass to get through the next day.

We are going to need to get new fridges designed to operate to say 60C below ambient.

Remember that the World's average temperature is about 15C & we are supposed to try & keep temperature increase to 2C & Australia is supposed to get some of the largest increases.

Peter_n_Margaret · Guru

Baz421 wrote:
Our Vitrifugo 12v van fridge overheated yesreday .

This is our Vitrigrigo fridge. It is a 130L fridge only with extra insulation around the cabinet.

The 43.8C is inside the camper. We have never had it not able to keep up.

Cheers,

Peter

Baz421 · Guru

Different model,,,, first here too. Was 43 here y day and parked in storage near hugh shed and 500mm from van, so anyones guess how hot it was. 48 here today didn't shut down. My model as i stated is not made for Oz temps.

T1 Terry · Guru

Household fridges these days must pass a very tough Aust Standards test involving the fridge and all it packed in test load saturated to 48*C, then switch on in a room that maintains the same 48*C and must pull the whole fridge load evenly down to 5*C and the freezer down to -15*C in 15 hrs with no external assistance such as additional fans to move the heat out of the fridge walls. Only once it has passed that test can it be submitted to the energy star rating tests and carry an Australian Standards approval and a star rating. You will never see a 12v or 24v fridge with an Australian Standards certification or a star rating, they simply can not achieve the test requirements.
This is the 21st century, why would you expect technology that didn't meet to requirements last century work these days? These fridge/freezers do not need additional insulation shoved up the sides or special vents to move the heat away from their condenser, the walls are the heat sink for the condenser tubes and can create their own natural air movement as long as the installation requirements are met.
A modern inverter style household fridge/freezer is a fraction of the price of a 12v/24v fridge and uses less electrical energy (including the inverter losses if a modern PSW correctly sized inverter) than a 12v/24v fridge, so why do people still buy them and expect them to work the same way as the fridge at home does?
Yes, you can build a special purpose low voltage fridge and freezer that may work as required, but not for the price you can pick up a good looking household unit from your chosen retailer. The other advantage is finding someone in the area you are in that can fix it, what are the chances of finding an good low voltage fridgie with all the gear required when your unit dies? At the very worst you can open the RV door and boot the dead one out and replace it with the latest model if you can't get it fixed or the repair cost including the fridgie's labour cost is more than a replacement item.

T1 Terry

Whenarewethere · Guru

You have highlighted the hypocrisy of standards.

A portable fridge is going to need to be able to cool down from a much higher ambient temperature, especially if it is in the back of a car in summer when you need it most.

KJB · Guru

Sounds like low current supply.....

T1 Terry · Guru

Whenarewethere wrote:
You have highlighted the hypocrisy of standards.
A portable fridge is going to need to be able to cool down from a much higher ambient temperature, especially if it is in the back of a car in summer when you need it most.

That is the point, there are no standards a portable low voltage fridge can actually meet yet the common thought was they were the better choice because they were made to suit the rough conditions an RV might see on the road. Sadly that is a misconception, if they made household fridge/freezers as poorly as they build RV fridge/freezers the manufacturer would spend most of their time in the Fair Trading court battling "not fit for purpose" cases. As for 3 way fridges and roof top rattler air conditioners, you would think if it was built for the RV market they would at least put some supports along the gas lines in the 3 way fridges and the refrigerant lines in the roof top rattlers

T1 Terry

BAZZA44 · Senior Member

Baz421 The Vitrifrigo has a Danfoss compressor that does not like to start when cabinet is overheated. Some sort of safety overload thing. The advise for this situation is to put a bag of ice or similar in the fridge cabinet to bring the temp down a bit. Then start the fridge and it should get going.

I remember reading this on a fridge site about Danfoss compressors.

Barry

Stretch60 · Senior Member

We have had consistent temps in high 40's for days now and 12v compressor Novakool is keeping everything nice and cold including the freezer.

Aus-Kiwi · Guru

Try and shade that side of van / motor home . Is it low voltage at fridge ? Possibly a temp
Sensor cutting it out ? Ours is vented pretty well as it had 3 way in same cavity before . Vents at bottom big vent up on roof .

Whenarewethere · Guru

If you have access to water & you have low humidity spray water of the side of the vehicle.

Last January we were in Mildura & it was 45, we went to the swimming pool. When we got out of the water we were frozen because the water evaporated of us so quickly. 30 seconds later back in the water.... repeat.... repeat.... repeat....

T1 Terry · Guru

Often we mount a thermostat on the fridge compressor ad a fan behind it to blow the hot air away from the cabinet while trying to cool the compressor housing a bit. We do this on both the low voltage fridges and the 240vac household fridges we install just to try and make life a little easier for the fridge in the hot weather. No idea if it really helps or not but I couldn't see it doing any harm. We use a 50*C N/O thermostat from Jaycar, a bit of heatsink past on the back and glue 2 screws to the compressor body so we can hold the thermostat in place once the glue sets.

T1 Terry

Baz421 · Guru

BAZZA44 wrote:
Baz421 The Vitrifrigo has a Danfoss compressor that does not like to start when cabinet is overheated. Some sort of safety overload thing. The advise for this situation is to put a bag of ice or similar in the fridge cabinet to bring the temp down a bit. Then start the fridge and it should get going.

I remember reading this on a fridge site about Danfoss compressors.

Barry

Thanks Barry you have hit the nail on the head Cheers

Baz421 · Guru

T1 Terry wrote:
Often we mount a thermostat on the fridge compressor ad a fan behind it to blow the hot air away from the cabinet while trying to cool the compressor housing a bit. We do this on both the low voltage fridges and the 240vac household fridges we install just to try and make life a little easier for the fridge in the hot weather. No idea if it really helps or not but I couldn't see it doing any harm. We use a 50*C N/O thermostat from Jaycar, a bit of heatsink past on the back and glue 2 screws to the compressor body so we can hold the thermostat in place once the glue sets.

T1 Terry

Yes have addition fan on compressor too, as I said has worked well on 42deg days in the past but it may have been well over 50 in cabinet due to where van stored.

Hetho · Senior Member

We have a Novakool 215 Ltr compressor fridge and it is brilliant. 46 degrees in Port Augusta 3 weeks ago; had it for 4 years.

Central Aust. Kimberly's and the top end. Best fridge for all temperatures. IMO.

Regards \.

Hetho.

Stretch60 · Senior Member

Hetho wrote:
We have a Novakool 215 Ltr compressor fridge and it is brilliant. 46 degrees in Port Augusta 3 weeks ago; had it for 4 years.
Central Aust. Kimberly's and the top end. Best fridge for all temperatures. IMO.
Regards \.
Hetho.

Thumbs up from me too Hetho, 45 in Lightning ridge and fridge only on setting number 4 of 7. Still thinking about the Rok?

Stretch

Baz421 · Guru

Ahh found a contributing factor to my problem, now I have time to investigate.

Fan on Danfoss compressor condenser has failed,,, my other one on other side of condenser working OK but didn't do the job.

Damn looks hard to get out too.

Cheers baz

Trevor law · Senior Member

Our danfoss fan packed in 12 Months ago so just bought a replacement fan from jarcar been ok (put it on outside condenser) worked ok but 2 weeks ago hot weather as hit .Fridge struggling ,so decided original fan had to come out, 4 hours later out 1 hour jarcar fan in.Still struggling,lots of Google over weekend found out that jarcar fan only moves 64cfm ,original fan moves 103cfm so order one and hopefully the extra cfm will cool the condenser better. May put jarcar fan as well as a trial .

hopefully this will help,good luck.

Trevor

Whenarewethere · Guru

I have used Noctua fans for years, bit expensive but quieter & more efficient. Their industrial fans have a higher pressure level apart from the volume. The most recent fan I put in although noisier, when installed it is not that much noisier. My 28 litre fridge is quieter than all the larger models so I thick this fan would not really make much more noise. More information on my installation here: https://thegreynomads.activeboard.com/t65231112/custom-6x20-watts-solar-setup-with-mppt/

New fan 120mm https://noctua.at/en/nf-f12-industrialppc-2000

The original Waeco fan was 92mm.

Baz421 · Guru

Trevor law wrote:
Our danfoss fan packed in 12 Months ago so just bought a replacement fan from jarcar been ok (put it on outside condenser) worked ok but 2 weeks ago hot weather as hit .Fridge struggling ,so decided original fan had to come out, 4 hours later out 1 hour jarcar fan in.Still struggling,lots of Google over weekend found out that jarcar fan only moves 64cfm ,original fan moves 103cfm so order one and hopefully the extra cfm will cool the condenser better. May put jarcar fan as well as a trial .
hopefully this will help,good luck.
Trevor

Hey thanks for that advice Trevor. Question ,,, was the original fan just glued to the condenser frame or how did you separate from frame,,,, I can't see any screws and I'm hoping to get it changed through van side wall rather than pull it out again.

Baz

swamp · Senior Member

HI
Hermetic compressors can have thermal overload either internal or external . There also canbe 1 or 2 pressure switches .

There are portables available with 50 75 100mm of insulation .

Baz421 · Guru

Whenarewethere wrote:
I have used Noctua fans for years, bit expensive but quieter & more efficient. Their industrial fans have a higher pressure level apart from the volume. The most recent fan I put in although noisier, when installed it is not that much noisier. My 28 litre fridge is quieter than all the larger models so I thick this fan would not really make much more noise. More information on my installation here: https://thegreynomads.activeboard.com/t65231112/custom-6x20-watts-solar-setup-with-mppt/
New fan 120mm https://noctua.at/en/nf-f12-industrialppc-2000
The original Waeco fan was 92mm.

Thanks for info Jonathon much appreciated

Trevor law · Senior Member

Our fan was fixed to condenser with 4 Phillip head screw and it wasn't easy to remove any of them lots of swear words and bruised hands ,I can't help if yours is glued on no suggestions for you .All I know is it a stupid design that is not meant to be worked on.Sorry I can't help all the best

Trevor

Aus-Kiwi · Guru

I fitted a solar fan on top vent on roof . I find the cooling like a chimney draft wise . Vents at bottom and top . The hot air rises . Creating a good drougt . Like a good beer !

-- Edited by Aus-Kiwi on Tuesday 29th of January 2019 09:13:26 AM

T1 Terry · Guru

If you add a foam baffle just above the lower vent between the wall and the condenser fins, then a second baffle halfway up between the condenser and the fridge body, any air movement will be forced through the condenser fins twice, you could even add a third baffle between the wall and the condenser just below the top vent causing the air to make 3 passes through the condenser. If you mount the fans/s in the top vent it will pull the air through the bottom vent, 3 times through the condenser and then away from the van so the hot air is not trapped inside or drawn back into the lower vent.

T1 Terry

DeBe · Guru

Very hot amb temperatures can cause the Electronic module on the compressor to over heat. If it gets to 100degC on the heatsink due to over heat or overload the compressor will stop, but the Fan will continue to run. The compressor will attempt to restart when the module drops to 90degC with an additional 66 second delay. It will also flash a fault code of 5 flashes if a fault LED is fitted. ( All fridges using these compressors should have a fault LED fitted. If not I would fit one). On my Waeco CR-80 fridge I fited an extra 80mm comp fan to blow fresh air over the control module as heat is the enemy of electronics & can cause premature failure. DANFOSS CONTROLER.2.JPG FAN.1.JPG FAN.2.JPG

Baz421 · Guru

Thanks for advice all,,,

New genuine compressor fan ordered today $75,,, si I'll check arflow against the Jarcar ones on offer.

Cheers Baz

Whenarewethere · Guru

You can get the Noctua fans at Techbuy or Mwave

This is the one I used:

https://www.techbuy.com.au/p/319241/COOLING_FANS_120MM/Noctua/NF-F12-iPPC-2000.asp

https://www.mwave.com.au/product/noctua-120mm-nff12-industrial-ppc-ip67-2000rpm-pwm-fan-ab55451

LUCKY LOZ · Veteran Member

T1Terry regarding your post on 25.1.19 are you saying to just buy a 240 volt household fridge for a caravan. Just lost me there.
If so how would you run it when travelling?

Also would it be viable in your opinion to buy say a 75Ltr Waeco for travelling and have just a household fridge in van to fire up when in van parks when staying for 2 days or more.

Just learning.
Lucky Loz