Refrigerator Coil Fan

[tripper]

I was thinking of installing either two 200 mm computer 12v fans or a 16" car radiator fan (with the power turned down some) on the intake vent for my lp refrigerator with a temp sensor. Has anyone done this before? I am aware of the commercial fan setups, they do not seem very well built. Or even installing them on the exhaust port (on roof).

 

[tx2sturgis]

I assume this is to get rid of excess heat...is the fridge struggling to maintain the set temp? Or just getting old?

I would not put the fan at the roof vent, since the air up there will be very warm, maybe even hot, when the burner is on.

BTW, you can buy computer style fans in the 24v versions that will slowly and quietly operate on 12-14v with no speed circuitry needed. They move about 1/3 of the rated CFM this way. 

You can also buy the 120vac adjustable attic fan controllers, and use that for temperature controlled on-off power for the fan. They have settings from about 80 to 120 degrees or so. They will directly control low voltage DC with no problems. I used one on my old motorhome when I converted it to a dorm-style fridge back in the day. There is a 'swing' of about 10 degrees, they are not a precise thermostat like you use for a furnace. 

A radiator fan is loud, and pulls a lot of current...of course you can use a high amperage PWM motor speed controller to reduce the speed and noise.

You don't want TOO much air flow, it might blow out the burner flame.

 

[John61CT]

It's very common to enhance ventilation for 12V compressor fridges, usually with the gentle silent computer type fans.

But never heard of doing so to increase efficiency for absorption type

Clearing the excess heat out of the living space after it's done its job, sure

But actually ventilating within the working area? I'd say make sure to research more.

 

[frater secessus]

I think sternwake did that one his fridge.

 

[B and C]

There was a guy that used to make a fan powered system for absorption fridges. When it is hot outside, absorption doesn't work as well. Think fridge on the sunny side in heat of the day. He had something in the shape of a house gutter with a downspout piece. The fan was in the downspout piece and the gutter part was up around the coils. With the updraft provided by the muffin fan, it made these fridges work better. Iirc, there was a thermostat (with switch) that would turn on the fan when it was too hot. The switch was in the living space for overall control of when it was running. This greatly improved the air movement from the cooler lower intake to the higher exhaust port.

 

[Chernobylite]

First post. This is actually quite common in RVs and most newer ones come with a fan or fans from the factory. There are several ways to do it:

1) Put the fan midway up the enclosure so as to draw air in from the bottom vent and direct it upwards to the condenser. This is how most RV makers do it.

2) Fan at the bottom near the lower vent, also directed upwards.

3) Fan at the top vent exhausting air across the condenser.

A normally open snap action thermostat of around 130F is typically used and mounted on the
condenser fin. They can be bought specifically for this purpose on Amazon or ebay. I use a small 12 volt adjustable PCB type temp controller with the remote probe on the pipe as it exists the condenser.

Alternately, if you have a roof vent, a solar powered fan is available.

Lastly, many people put a fan inside the fridge either on the bottom blowing upwards or on the evaporator itself.

Any of these mods will improve your fridge's performance in hot weather.

 

[tripper]

Thanks, many good suggestions here, my fridge actually works decent and is fairly new, but I do have to crank it way up on hot days. I just want to make it more efficient so its uses less propane, and to get a hard freeze on ice cream.

 

[tx2sturgis]

I think sternwake did that one his fridge.

Yes he did....mainly to cool the compressor if I remember correctly.

Of course this is an LP fridge, so there is no compressor, but the cooling unit on the back of the fridge that faces the vents depend on airflow just the same. 

As they age, 10-15 years or so later, some will tend to work longer to do the same job....just the nature of the beast.

 

[Chernobylite]

Thanks, many good suggestions here, my fridge actually works decent and is fairly new, but I do have to crank it way up on hot days. I just want to make it more efficient so its uses less propane, and to get a hard freeze on ice cream.

If the fridge is in a slide out (has a top vent rather than roof vent) simply removing the vent cover will help as will adding a piece of curved sheet metal above the condenser to prevent heat from being trapped in any area above it. The lack of such baffling is a common problem in RVs.

Course, having that side in shade will help too but for colder freezer temps the best solution is a fan inside the fridge portion either on the bottom blowing up or multiple fans in front of the evaporator fins. They can be wired to the door light switch or by running wires down through the condensation drain.

Thin, quiet, low current and runs 24/7. Makes my ice cream hard. I have a muffin fan outside in the cooling unit enclosure but it never runs as long as I leave the vent cover off. Anyway, good luck.

 

[Weight]

The absorption fridge will never be ideal. Save up for a 12 volt compressor fridge.

 

[Burbanlife]

On the absorbtion fridge in my camper, I have a vent fan that helps exhaust the heat away from the coils, and inside I have a fan in the fridge section and in AZ heat it does alright

 

[Zoomyn]

Clean coils work better, worth it to polish them and the insect screens up every so often... peeling paint acts like insulation too until it falls off & rust sucks. Check to see if gunk from the low temperature propane pilot light heat source has carbon felt boogered up the boiler heating surface. Yeah, I've got two 1970's Dometic propane fridges. Anyhow, do the cleanings to see if it helps before adding a fan.

 

[tripper]

I have a 12v compressor freezer/fridge too. I like it. When boondocking I keep it stocked full of pork roasts, steaks, vodka, tequila and white castle burgers! I am always tinkering on my RV to make it nicer/better/more efficient.

 

[tx2sturgis]

When boondocking I keep it stocked full of pork roasts, steaks, vodka, tequila and white castle burgers! 

Tequila....it's not just for boondocking anymore....

You can drink it out on the back patio too!

:angel: