Gas vs Electric Refrigeration (1 Viewer)

[RockieRV]

Ok so here is the question.

In a field with no electric, so LPG powering the fridge. It is so much colder than electric, that it freezes everything.

So, two questions -

Why?

and howcome the coldest part of an RV fridge is at the top, when cold air is heavier than warmer air?

(BTW I understand -80 C refrigeration, I just don't understand this)

 

[Lindy-C]

That's funny.....mine normally freezes the stuff in the salad bins at the bottom

Why they run colder on gas I have no idea......probably the same reason the Magic Chef will cremate the bottom of a pizza whilst leaving the top beautifully frozen.........an RV appliance manufacturers trade secret which they have probably spent years developing!

 

[RockieRV]

Thanks Linda. 17 views and just one response........... so you all know what I am talking about, but nobody knows why Now I don't feel so bad.....

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[scotjimland]

Thanks Linda. 17 views and just one response........... so you all know what I am talking about, but nobody knows why Now I don't feel so bad.....

We are far too polite on here to embarrass you Sharon

 

[Brisey]

We have 2 temperature regulating dials on our fridge, one for gas and the other for electric which may explain the difference in temperatures.
Why is it colder at the top?? My only thought on this is that as cold air falls, perhaps the refrigeration matrix is positioned at the top of the unit to allow the cold air to drp to the bottom of the fridge. Hence the coldest air is always at the top.

I'll get me coat

 

[RockieRV]

Thanks Brisey.

And Jim - Go for it, especially as we know each other

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[sammclouis]

we have not noticed a difference between elec 'n' gas..but once dave turned the dial up to 7 (when we just had the motorhome) ...ever tried frozen mushrooms & carrots...not bad!!!

 

[TestPoster]

OK.... without getting involved in a discussion about thermal dynamics
Gas heating on the heat exchanger is far more efficient than the electric element, there is more energy released from the gas burner and so the rate of temperature rise is higher, therefore the more heat is removed from the fridge, I do have a real techy document somewhere if anyone is really interested. I think that Brisey is right, the evaporator is at the top of the fridge so that the local area to the evap will be much colder and the food on the shelves traps the colder air toward the top of the fridge whereas the air at the bottom is warmed to some extent by the food in the box, if that all makes sense
Beat ya to it Jim

Keith

 

[GeorgeTelford]

Hi

On gas during the winter this is noticable due to how the heat exchanger works on a three way fridge, the cooling is dependant on the ambient temperatures, that is why there are winter covers to stop the outside cooler temperatures over freezing the fridge.

Under normal operating temperatures (summer usage) you will find that 12v tends to overfreeze and the gas due to Ambient temperatures as a harder job cooling.

The other point that is hard to express is that 100 C represent different amounts of heat energy depending on the medium, Air and water at 100 C have the same temperature, but different amounts of heat energy.

If you stick your hand in an oven at 100 C and wave it about no problem put your hand in water at the same temperature and you will require hospital treatment for scalding.

George

PS time to fit the winter vent covers

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[RockieRV]

Thanks everyone - I'm still glad I asked!!
Any more answers gratefully received.....

 

[GeorgeTelford]

Didnt finish off as I noticed Keith as pretty much nailed the top vs bottom temperature differential

 

[TestPoster]

Hi George
Don't say nailed...... That could lead to a hole and as it is my fridge that Sharon is talking about I don't want any holes in it
I like your oven / bucket of water analogy, sums it up pretty well in my opinion.

Keith

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[Adria 5]

what my fridge runs on gas too!!!!! i!!!!!!!!!!!!!!!


oh: ray

 

[BGD]

I know why the air at the top is colder than below.................your fridge has in fact been fitted upside-down.

Remove it, up-end it, replace it, and all will undoubtedly be fine.

Alternatively, I guess you could leave the fridge in situ, but turn the motorhome upside down.

:Cool:

 

[johnsandywhite]

:Cool: Just as an addition to this thread about LPG as against Electricity. If you are on a camp site that you have to pay by the KW? It would be cheaper to run on LPG than on Elecgtricity.

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