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Open Roads Forum  >  Tech Issues

 > Does humidity affect refrig. cooling?

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bob213

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Posted: 05/16/19 01:17pm Link  |  Quote  |  Print  |  Notify Moderator

Arrived in Branson, MO 2 days ago. Refrig worked fine till we got here. Been running on electric and then temps started to rise. Switched to propane last night and this A.M. temps were down to 4 freezer and 34 refrig. Outside temp in high 80's and humid. Refrig is now at 8 freezer and 41 refrig. Is this normal for higher humidity or do I have a larger problem?


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DFord

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Posted: 05/16/19 01:37pm Link  |  Quote  |  Print  |  Notify Moderator

Make sure your fans behind the refrigerator are functional and there's nothing like wasp or mud dubber nests blocking the air flow. It's going to be long hot summer when it finally gets here.


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wolfe10

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Posted: 05/16/19 02:28pm Link  |  Quote  |  Print  |  Notify Moderator

Yes, humidity is one the many, many factors affecting refrigerator performance.

It takes a lot of BTU's to condense water vapor. Same for an air conditioner--you will get a greater temperature delta between incoming air and air out the vents in Arizona than in Florida!

Same for cooling beer in the refrigerator.

But, check "the other stuff" as well:

Dollar bill test on door seals.

Mostly full, but not blocking air flow.

Not opening more often than necessary.

Propane performance: make sure you have done the annual "burner area tune-up".

Good air flow up the back/outside AND have verified correct installation (correct dimension behind, on the sides and above the refrigerator. You would be shocked at how many RV manufacturers DON'T install per the installation instructions. Plenty with excessive clearance in back, open above, etc.

If you have a fan to augment air flow over the condenser (top, back of refrigerator), make sure it is working.

* This post was edited 05/16/19 03:39pm by wolfe10 *


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MEXICOWANDERER

las peñas, michoacan, mexico

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Posted: 05/16/19 03:26pm Link  |  Quote  |  Print  |  Notify Moderator

I posted this is simpler terminology.

85F

75% R/H

Twenty minutes no temperature change, but a drop to 61% in R/H
Then the temperature started ramping down

ajriding

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Posted: 05/16/19 06:14pm Link  |  Quote  |  Print  |  Notify Moderator

Relative humidity will have very little effect on cooling of the fridge.
Unlike a person, who perspires through skin water evaporation, the fridge only conducts heat away. The fridge will cool almost the same in dry and in humid air.
The differences will be less than 2%; un-perceivable if just measuring your temperature in the fridge.
You problems lie elsewhere.

Do you have a fan running behind the fridge? When you drive the air is flowing rapidly through the rear compartment, so fridge cools easier. When you stop the air stops and temps can rise behind the fridge, even with a fan running, but especially with no fan. If you park with fridge side to the sun in the sun then temps get higher and affect cooling.

If you run it off-level while parked for too long then you cook the anti-corrosive chemicals and ruin the fridge. It will not cool.

babock

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Posted: 05/16/19 06:31pm Link  |  Quote  |  Print  |  Notify Moderator

ajriding wrote:

Relative humidity will have very little effect on cooling of the fridge.
Unlike a person, who perspires through skin water evaporation, the fridge only conducts heat away. The fridge will cool almost the same in dry and in humid air.
The differences will be less than 2%; un-perceivable if just measuring your temperature in the fridge.
You problems lie elsewhere.
Incorrect. The heat content of humid air is higher than dry air. The cooling fins not only cool the air but have to condense the water contained in the air. More BTUs are required to lower the temp of moist air vs dry air. It's not a lot but it is definitely more.

Has nothing to do with the way the skin feels during low or high humidity.

* This post was edited 05/16/19 06:56pm by babock *

Chum lee

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Posted: 05/16/19 07:04pm Link  |  Quote  |  Print  |  Notify Moderator

babock wrote:

ajriding wrote:

Relative humidity will have very little effect on cooling of the fridge.
Unlike a person, who perspires through skin water evaporation, the fridge only conducts heat away. The fridge will cool almost the same in dry and in humid air.
The differences will be less than 2%; un-perceivable if just measuring your temperature in the fridge.
Your problems lie elsewhere.
Incorrect. The heat content of humid air is much higher than dry air. The cooling fins not only cool the air but have to condense the water contained in the air. Many more BTUs are required to lower the temp of moist air vs dry air.

Has nothing to do with the way the skin feels during low or high humidity.


Humid air also conducts heat better so that humid air of a given temperature will transfer MORE heat through the outer shell of the refrigerator to inside the box than dry air.

Dry air (inside a sauna for example) helps cool the skin through evaporation of sweat better than a steam bath at the same elevated temperature.

Generally, there isn't a lot of evaporation taking place on the exterior surfaces of the refrigerator because it is only slightly cooler than the environment and there are no sweat glands. That's why some refrigerators (residential mostly) have the "reduce exterior moisture" heating coil function for humid climates.

Chum lee

marcsbigfoot20b27

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Posted: 05/16/19 08:40pm Link  |  Quote  |  Print  |  Notify Moderator

I would be more worried about introducing warm moist air into the fridge by frequent opening of the door than the ambient humidity affecting anything on the outside.
Interesting read.
Cas study of humidity on refrigerator case.

Chum lee

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Posted: 05/17/19 12:16pm Link  |  Quote  |  Print  |  Notify Moderator

marcsbigfoot20b27 wrote:

I would be more worried about introducing warm moist air into the fridge by frequent opening of the door than the ambient humidity affecting anything on the outside.
Interesting read.
Cas study of humidity on refrigerator case.


RV refrigerators aren't really considered display cases, but it is an interesting study. Turns out, most of the humidity inside an RV/residential freezer comes from the ice making process. Think about it. Warm water enters a much cooler dehumidified space. Evaporation occurs, . . . . . frost forms in the air, then turns to ice on the colder surfaces. (yeah, yeah, I know about sublimation too, but you can look that up in your chemistry book if interested) Most RV refrigerators have a condensate drain (which drains to the outside) to handle the condensed moisture inside the refrigerated portion of the space.

Regularly opening the doors in humid air does add significant humidity/condensate too.

Chum lee

pauldub

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Posted: 05/17/19 12:24pm Link  |  Quote  |  Print  |  Notify Moderator

Usually a fridge will cool better when running on propane as opposed to electricity. I usually have to change to a cooler temp setting when running on electric.

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