Adequate Ventilation For Engel Fridge

[MANXMAN]

I have decided not to use the small 3 way fridge I bought for my camper and just received a Engel MT45 to replace it.

Reading through the owner's guide it says that the fridge should be at least 6" away from solid walls for maximum cooling efficiency and minimum electrical consumption.

I've seen many pictures of these units in campers and don't remember seeing them that far from the walls or cabinets. Anyone with experience with these fridges care to offer an opinion about whether or not that much clearance is needed? How much clearance does yours have and how much heat does it give off?

6" clearance on each side of the fridge and 6" from the back wall is more room than I have.

Thanks
Manxman

 

[DesertDave]

Since no one has answered I will take a stab at it. My answer is based on the Dometic in my camper, so not specifically aimed at your model.

These fridges are often installed in boats - the install diagrams for mine showed a similar venting scheme as you describe, a way to get colder air from down low in front of the fridge, up past the condenser coil on the back and then up and away. Since we have a different install we can bring in colder air from down low on the back and exhaust it up high on the back, thus removing the heat. That is how the camper manufacturers install these. One low and one high opening on the outside of the camper. Such venting would sink a boat ;-)

Now for the amount of air, I feel one can improve the performance of the fridges by a proper application of small fans that would move more air past the condenser coil and out of the upper vent. I read a lot of stuff on WTW about this, and a post by Dr. J. where he indicated about a 30% reduction in the amount of electricity used with fans vs. without fans convinced me to install a couple into the frame of the upper vent blowing outward.

I have about a 4" depth of air space between the back of the fridge and the frame of the camper.

 

[DrJ]

Maxman,

I have noticed FWC over the years has changed their designs as far as fridge ventilation for compressor fridges. I've seen them with only a side vent to the inside of the camper. I've seen them with only one outside vent. I've seen them with 2 vents - one upper, one lower - which is what I've got.
The compressor system is much more efficient than the 3 way fridge ammonia system. However it still creates a lot of heat that is trapped in the small enclosed areas we all have our fridges in.
Without some air movement that hot air stays there and makes the system ineffectient. The compressor has to run more often.
If I was redoing my system I would have one outside access panel below for cold air intake. Then I'd make an internal vent on the top of the fridge with fans to pull air to the inside of the camper. I think this would vastly improve the efficiency of the system.
I'm sure that Engel publishes installation recommendations on how much clearance you need. And I would guess that most of our setups in FWC have less clearance than recommend or just bearly meet their standards.
I have noticed an improvement with my amp hour useage by running the fans during the days when it's at least 60 degrees. I think below that temperature it doesn't seem to make as much of a difference.

 

[DrJ]

DesertDave,
You'll have to let me know how your fan system works too. I'm curious to see if it makes a big difference in your setup too.

 

[DesertDave]

DesertDave,
You'll have to let me know how your fan system works too. I'm curious to see if it makes a big difference in your setup too.

I don't have any means of accurately measuring amp draw, but once the ambient temps get higher I can give you some anecdotal info compared to last summer, ie morning battery voltage before the solar controller turns on. Lately the batteries are always at 13.0V in the AM, the same voltage they hold in storage.

 

[MANXMAN]

Maxman,

I have noticed FWC over the years has changed their designs as far as fridge ventilation for compressor fridges. I've seen them with only a side vent to the inside of the camper. I've seen them with only one outside vent. I've seen them with 2 vents - one upper, one lower - which is what I've got.
The compressor system is much more efficient than the 3 way fridge ammonia system. However it still creates a lot of heat that is trapped in the small enclosed areas we all have our fridges in.
Without some air movement that hot air stays there and makes the system ineffectient. The compressor has to run more often.
If I was redoing my system I would have one outside access panel below for cold air intake. Then I'd make an internal vent on the top of the fridge with fans to pull air to the inside of the camper. I think this would vastly improve the efficiency of the system.

Thanks for the replies.

I think that if I give the fridge 2"-3" of clearance on each side and install it where the wall vents for the 3 way fridge are, I should be alright. The two wall vents hopefully will allow enough of the hot air to vent away from the back of the fridge even with only half the side clearance Engel says to give it.

 

[RC Pilot Jim]

Manxman

I have the Engle MT-35 top loader portable. It sits under the front window on my Eagle. sitting cross-wise (picture in my build).

the right side by widow is 4 inches from the wall. Panel above the controls is the handle width from drivers side of camper (maybe 3 inches). Left side faces open area of camper (70 inches). Packed for traveling. some of the left side clearance less than two inches. It doesn't affect cooling at all.

 

[MANXMAN]

Sounds like I'm going to be ok then. I'll go ahead with the 2-3" side clearances and rely on the camper's sidewall vent at the back of the fridge to dissipate whatever heat there might be.

 

[ntsqd]

I found a thermostat for the computer-type box fans that I installed pushing out thru the upper vent. They made a difference on hot days, but the t-stat the I got is too low of a value, the fans would run almost constantly if I hadn't also wired in a switch to turn them off when not needed. Right now I can't say what that temp setting is, but I've also got an adjustable t-stat that I plan to use when I re-wire the system.

Per our TriMetric monitor it is quite surprising how little current these fans draw.