Engel MT35/45/60 question

[frogg]

When you turn your Engel MT35/45/60 fridge on for the very first time (let's say, with the fridge at room temperature), approximately how long does it take before the evaporator (the white panel on the inside) goes below zero?

(Evaporator temperature please, not air temp)

[W&KO]

I have an Engel in the work car......not sure I have anything to test the surface temperature of the evaporator

[frogg]

Thanks W&KO - If you don't have a thermometer, how long before it's covered in frost?

[W&KO]

Just thinking, I do have a infrared gun, I get my work car on Monday.

[Saitch]

I bought a new MT60 about 4 months ago and it is on 24 hours a day as my ale cooler. It is at 0° and if you look at the internal pic, you will notice a little bit of beading in the bottom left of frame. That is all it's done from day one.
My old 40 litre would frost up a bit but I put that down to the 30 year old seal on the lid being a bit dodgy.

[frogg]

Saitch - when the fridge is off (warm), then switch it on - how long (in minutes, seconds, or hours) before the white plate (the evaporator) goes to 0 or frosts over?

pretty much instantly?

[Blknight.aus]

Saitch - when the fridge is off (warm), then switch it on - how long (in minutes, seconds, or hours) before the white plate (the evaporator) goes to 0 or frosts over?

pretty much instantly?


after the compressor starts...

it should be about 15-30 seconds before the inlet point of the evaporator plates temp begins to drop.

after about 2 minutes (depending on starting point, temp, plate size) you should be getting a 0 reading or below at the inlet.

Some fridges have a built in start up delay on first power up and some have a "soft start" on the compressor to reduce initial start up current.

[frogg]

For posterity's sake, I've gone ahead and performed the test I requested using my own MT35F. Below is the results.

152765

[scarry]

That graph is in degrees F.

those temps are very low,-17 degrees F is way lower than that Engle is designed for.

I would suspect my 35 yr old 29 litre Engle would fully frost the plate after around 20 minutes,at 22 degrees ambient,therefore plate temp would be less than 0 degrees c.

Plate temp would gradually creep down to around -25 C or slightly lower at freezer temps

[frogg]

hey scarry,

Sounds like a bingo on around 15-20 minutes for the 0 deg C mark in the Engels - same with my experience and others in this thread.

The Engel is very much designed for extremely low temperatures. The components are rock solid and are capable of going lower if the ambient temps are lower.

As the ambient temps go up, so the lowest temperature the fridge can go to goes up. It all depends on operating conditions. My highest outside has been 36C, and the evaporator seems to stop at about -14 deg C there (though this was with sun on the lid bringing it around 37.8C)

[scarry]

Yes,you will find that the Engle is designed to hold conditions at a certain ambient,without a check on google,guessing it maybe around 35 degrees.

From my experience,once ambient temperatures get above 35 degrees,they struggle to hold -20 degrees C,even running continuously.

When travelling,we organise things so the Engle is only used as a refrigerator,not a freezer.

This not only works the cabinet easier,but also reduces battery drain.

[rick130]

Paul, have you ever bothered putting a fan on the condenser?

Coffee time atm, trying to wake up.
4:45am finish this morning......

[frogg]

Thermal analysis of the Engel MT35F evaporator. The video is 20x speed. Total elapsed time after turning on unit: 20:00 minutes. Temperature readings are probably off - the specs are somewhere around +/- 5F and the emissivity is very difficult to control.

153540
Engel MT35F Thermal Analysis (20x speed) from umb iilicam on Vimeo (https://player.vimeo.com/video/353710246)

Within 10 seconds of being turned on, the condenser (at the rear of the unit) goes to an almost totally uniform 41.6 C in 23.9 C ambient conditions, meaning roughly 17.7 C temperature differential. This seems to be pretty consistent with my experience at 32.2 C, with the condenser hitting 50 C.

The compressor itself stays fairly cool - slightly higher than ambient, but much cooler than the condenser for the most part.

You can put fans anywhere on the condenser as the temperature is almost uniform from top to bottom.

[frogg]

So I've been operating my MT35 for a while now with two 24V condenser fans (instead of the single 24V fan that comes stock.) and I have to say that while it may have some small benefit for the compressor, it doesn't seem to move the needle in a noticeable way for internal temperatures. (Maybe someone out there can do a test with a much larger fan or some crazy blower and see if that helps.)

What does help noticeably with lower temps to a huge degree is insulation, insulation, insulation. If I wrap my engel 'round with a cheap blanket (careful not to cover the vents!), I reckon I get an easy 3-4 degrees centigrade lower temps in the fridge.

I bet if someone had some really nice, thick, high efficiency insulation that they could sew up around their fridge, it could help with high outside temps.