AC and fridge performance in high heat

[JoeTampa]

So, summer is here with a vengeance in Florida. Temps have been in the 90's with 90-100% humidity lately.

On Thursday afternoon, I turned the fridge on (propane) in anticipation of taking it out on Friday for the weekend. Temps were in the mid 90s in the trailer, fridge, and freezer (I have thermometers in all). On Friday afternoon when I went to pick the trailer up, temps were only down to 70 in the fridge and 60ish in the freezer. They finally got to the right temps overnight going in to Saturday. Since then, they have struggled - the fridge, mostly - to stay at temp, and I find myself in the place where if I don't set the temp to the coldest setting, the fridge goes above 40 during the day. If I DO set it to the coldest setting, it goes below freezing overnight. I added a battery-powered circulating fan in the fridge to help the cold air circulate yesterday. I don't yet know if that will help.

I also noticed that the venting is somewhat less than spectacular, as it is over 120 degrees not only in the vent area, but also inside the trailer in the pantry and storage compartments on either side of the fridge. The walls are quite warm to nearly hot to the touch.

There is a fan in the vent area blowing up through the baffles (and presumably out the vent), but I didn't discern any meaningful airflow. I put another small fan (12v computer fan) on the baffles blowing straight out the vent cover to see if that helps any, which I guess I will figure out today. The vent cover vent holes are angled downward - in deference to rain, presumably - which would appear to be a potential issue as well.

We have dual AC units in the trailer. They are also unable to keep the temperature down. With the thermostat set to 74, the temp climbs up to 82 or so during the day until the sun starts to go down.

Is this everyone else's experience as well? Any words of advice?

[mike837go]

You are at the extreme limits of the capability of the equipment.
If you check the manuals, you'll find that temps above 90F will severely limit the cooling capacity of a gas absorption fridge. And that an A/C unit only provides 40F or 50F reduction in air temperature.


Getting the RV into a shady place with the curtains closed and limit going in and out of it. Plus stop opening the fridge every hour to check the temp.

[JoeTampa]

Originally Posted by mike837go

You are at the extreme limits of the capability of the equipment.
If you check the manuals, you'll find that temps above 90F will severely limit the cooling capacity of a gas absorption fridge. And that an A/C unit only provides 40F or 50F reduction in air temperature.


Getting the RV into a shady place with the curtains closed and limit going in and out of it. Plus stop opening the fridge every hour to check the temp.

We don't have the option to move to a shady spot, unfortunately. I actually put some reflective sunshade in some of the windows, but it was too late in the day to determine if it helped. The shades have been drawn continuously, and I don't have to open the fridge and freezer to check the temperature - I have a wireless unit with the display mounted outside.

I am wondering if the excess unvented heat from the fridge is both hampering its performance and raising the temp in the trailer.

[mike837go]

Originally Posted by JoeTampa

We don't have the option to move to a shady spot, unfortunately. I actually put some reflective sunshade in some of the windows, but it was too late in the day to determine if it helped. The shades have been drawn continuously, and I don't have to open the fridge and freezer to check the temperature - I have a wireless unit with the display mounted outside.

I am wondering if the excess unvented heat from the fridge is both hampering its performance and raising the temp in the trailer.

I'm sorry if my idea of a sense of humor seemed insulting "checking the fridge every hour" was used as hyperbole.

As you say, when the sun goes down, the equipment handles the load.

The heat from the fridge doesn't influence the cabin temp. By law (and generally a good idea) all of the airflow associated with the fridge (especially combustion gasses) are to be sealed away from the occupied cabin.

You are dealing with a sun-load issue. Sweat it out. Only 84 days of summer left.

[wags999]

Your RV is a metal tube, surrounded on all sides by hot air. The walls are less than half the thickness of a brick and mortar home, roof is the same. There is no way they could effectively put an AC that could handle that heat load, especially since most folks don't camp in those extremes. Here in Az, I checked the surface temperature of my TT. The white metal surface temp, in the sun, was 144 degrees. Fortunately i'm not living in my RV. The air temp was 114 at the time.

I know it's frustrating, but, it's just reality that no RV will be able to keep indoor temps low in extreme heat situations. On the other end, it was also difficult to keep our unit warm (without portable heaters) when the temp dropped into the 20's with wind. Sometimes you can't help being in these extreme temps.

Good Luck and drink lots of lemonade

Reflective coatings in windows does help, and as said above limiting opening doors etc. Also having your awning out can help, if possible. Anything to shade any part of the rig.

[JoeTampa]

Originally Posted by mike837go

I'm sorry if my idea of a sense of humor seemed insulting "checking the fridge every hour" was used as hyperbole.

No, it's a legitimate point. I could have had internal thermostats hanging there that required opening the fridge and freezer to check.

Originally Posted by mike837go

The heat from the fridge doesn't influence the cabin temp. By law (and generally a good idea) all of the airflow associated with the fridge (especially combustion gasses) are to be sealed away from the occupied cabin.

So the heat from the fridge raising the temp of the pantry and storage compartment to 120 degrees is normal/acceptable?

[Dustdevil]

Any kind of shade you can manage will help. Awning on one side, and any sort of tarps you could use to shade the opposite side will assist in keeping the direct sunlight off the walls. If you can shade part of the roof, that helps tremendously. Just don't cover your AC or vents to allow them to circulate the hot air out. Rinsing down the outside walls with a hose can temporarily give the AC the chance it needs to get on top of the heat. Especially if they are aluminum. Same with the roof. While you're at it, put on your swim trunks and hose yourself down and grab a cold drink.

[mike837go]

Originally Posted by JoeTampa

So the heat from the fridge raising the temp of the pantry and storage compartment to 120 degrees is normal/acceptable?

How do come to the conclusion that the fridge is responsible for extra heat inside the RV?

As someone else suggested, the heat transfer from the sun-soaked siding is a much more probable culprit.

[JoeTampa]

Originally Posted by mike837go

How do come to the conclusion that the fridge is responsible for extra heat inside the RV?

As someone else suggested, the heat transfer from the sun-soaked siding is a much more probable culprit.

The temperature at the top of the pantry is much warmer, and the side of the pantry closest to the fridge is much, much warmer than the other sides and rear.

Thermal image

The fridge is on the left side.

[mike837go]

Originally Posted by JoeTampa

The temperature at the top of the pantry is much warmer, and the side of the pantry closest to the fridge is much, much warmer than the other sides and rear.

Thermal image

The fridge is on the left side.

The column for all of the gasses (fresh air for combustion, products of combustion and air to move all the heat out the top vent)

Have you imaged the outside of the trailer to look for hot (and hotter) spots?

How hot is the access cover for the back of the fridge? On my trailer the darned thing is black. And therefor will convert more sunshine to heat than the white siding. What's yours?

[BigJohnD]

Residential fridge like we swapped to will solve all the fridge cooling issues. On the AC, we can maintain 72 deg inside in full sun / no shade, 96-98 deg outside temp, BUT, that's with several changes / modifications. This is with a single 15k AC / 33' rig. We've full timed in a couple of rigs, and keeping cool is a must, so when things don't stay cool, I'm axing away at stuff to make it work. I managed to get our 40' / 4-slide fifth wheel to maintain 72 in the same temps, but again, with several changes. It can be done. Some of the things I've done, people aren't willing to do as they're scared of voiding a warranty, or just don't like the change.

[Doboy Dawg]

Originally Posted by mike837go

You are at the extreme limits of the capability of the equipment.
If you check the manuals, you'll find that temps above 90F will severely limit the cooling capacity of a gas absorption fridge. And that an A/C unit only provides 40F or 50F reduction in air temperature.


Getting the RV into a shady place with the curtains closed and limit going in and out of it. Plus stop opening the fridge every hour to check the temp.

An air conditioner normally provides a 15-20 degree temperature drop. A unit providing a 40-50 degree temperature drop would be refrigeration.

Like previously posted you are at or above the design load of the equipment. If your in a campground or RV park, there are dozens of other units loading the power grid at the peak load times. I hope you are using a power maintaining device, for low voltage protection.

The other posters are pretty much spot on, you need some shade or a swamp cooler. A redneck swamp cooler is simply a water sprinkler on your roof. The other alternative reverts to the early days of AC, coolers of ice with air directed across it.

[Vaquero]

It was 108 yesterday. Dry heat. No shade.
88 inside.
Sounds like my unit is doing all it was designed to do.
Bummer.

[bigbird]

I find the reflective shades help quite a bit and I'll leave some in near the bed to keep it dark in the morning. We bought ours at the dollar store.

[Camper_bob]

Last weekend we were out. Fridge worked just fine, no problems there. AC struggled in the middle of the day; kept the trailer at 78. External air temp was right at 100, and the trailer was in almost full sun. Awning was out, but that's all the effort we made to keep it cool. I have a roll of Reflectix in my garage, but it has not yet been deployed (DW thinks it will "look trashy"), so I plan to use it in other spots where it can't be seen.

FWIW, we gave up and went home. It was just too hot. The pool at home helped tremendously, so I would second the suggestions to find a way to get wet, it will help.

[bigbird]

I'm sure everybody thinks we look trashy but we feel so "cool".

[Chrislorl]

I removed the vent cover on the top of the camper and added two computer fans blowing upward. This has made a huge difference in our frige/freezer combo. I also added a small internal fan to move air over the cooling fins. Together these have made it work in central Florida heat with no problems at all. Yes we have 2 ac units running inside too.

[hoppers4]

The upper fridge vent on my rig has a 4.5" muffin fan. This fan never worked even in high temps. I jumped out the thermostat and put a switch in to control the fan. I also installed a product called Fridge-fix from SmartRVProducts.com. This is a dual fan unit that installs on the top of the interior of the fridge. Rather spendy at $125 but it helps the fridge do its job. These absorption fridges aren't the most efficient units on the market and they need all the help they can get. These two things have improved the fridge to make it more efficient and the Fridge-fix also alleviates the need to defrost the it every other day.

FYI, to prevent auto defrost every other day I turn the fridge off every day for a couple of seconds and then turn it back on.

[Vaquero]

I went to Cabelas and got a 3oz "nasa" survival blanket.
I've cut it up to fit the west facing windows and got it installed.
Heat transfer through glass is almost zero now.
Hoping for a more comfortable evening tomorrow.