Ventilation of Freezer Compressor Heat

[lwarden]

Under the settee is both the 110VAC freezer compressor and the inverter charger. There is very little ventalation and I noticed during the summer it was very warm down there, enough so that I pulled the seats to let some air in. I suspect this is making the freezer work very hard to maintain temperature (and probably no good for the inverter either).

I'd like to add some forced air cooling to this area. It appears that I could do this by boxing the compressor and adding a 4" duct flange then running this up to a dryer type vent located just above it. The compressor has a 5" muffin fan drawing the air across the coils. There would be an opening to the inside of the settee air space on the draw side of the coils to allow the cool air in. The trouble is, the dryer vent isn't very appealing and it would be located in the cockpit. Another idea was to do the same box but open up a hole to the engine room to allow the hot air to be pushed down where the air is already hot. Something tells me that this might not be a good idea and figured you guys might be able to shed some light on this or have other ideas. My guess is that without some sort of damper this wouldn't be wise.

I'd like to avoid a secondary fan to vent the settee area since when it needs to be vented is when the condenser fan is running, so might as well use that to also move the hot air out.

I'm interested in any ideas.

Thanks,

 

[Comodave]

I would absolutely not try to push hot air down into the engine room, you will be working again physics since hot air wants to rise. It wants to rise so help it rise, find a way for the cabinet to vent out the top. It does help to have a fan boost it out. Have an intake down low. A photo or two would help us visualize the setup.

 

[lwarden]

Here are a couple pics.

 

[Comodave]

It looks like you have room to add a low and high vent. Just cover the hole with a nice S/S grill. Add a fan that either blows air in the lower vent or out of the higher one. Wire it to the compressor so when the compressor runs the fan will also run. I did this on our last boat with the refer cabinet and it made a huge difference. I used a 50 mAmp fan so the current draw is negligible. This is the fan I got from Amazon.

Noctua NF-F12 PWM, Premium Quiet Fan, 4-Pin (120mm, Brown)

 

[catalinajack]

Those cooling fins need to be vacuumed.

 

[catalinajack]

Lwarden, you did not post pictures of the settee, only the horizontal hatch on which your cushions sit. How about cutting in grills in two vertical locations and installing fans to draw air in at one end and out the other. Muffin fans driven and triggered by your compressor circuitry are likely to be limited to .5 amps current draw which will limit the cfm of the fans. You could use the compressor circuitry to power a relay and the relay to power higher amperage fans.

What is the temperature in there when both the inverter and fridge are running? Inverters usually have a temp spec that is recommended not to be exceeded.

 

[Comodave]

The fan I referred to in post #4 only draws .05 amps or 50 mAmps. Most compressor circuit boards can handle that. My last one specified .5 amp.

 

[BruceK]

Difficult not seeing the boat, but can you run a fan powered duct tube from near the compressor, through the under settee area,exhausting high (safety)through the cockpit bulkhead, with a plastic intake vent in the side of the settee base.
(My previous boat had a 12v undersettee fridge/freezer compartment with compressor in the ER. Worked well, but a power hog. The cold plate system compressor,wisely located directly under the ER exhaust fan duct, worked better.)

 

[lwarden]

Lot's of good suggestions guys, thanks.

Attached is a view of the cockpit. The current plan is to use a 4" vent where circled in red. This area is right above the compressor. This is right above the freezer and some warm air will end up going onto the top of the freezer, but I think it will have minimal impact on the lid and heat load since it's insulated.

I will try and do the box up of the unit so that I can use the existing fan to exhaust the warm air, if that fails I'll add an additional 110VAC muffin fan.

The compartment has some inlet vents down low already and if needed I'll add more.

Second picture shows the settee area and the compressor is located in the far corner.

 

[lwarden]

Putting a bow on this thread...

I have the freezer vent box installed and the results are good. Without the box, temperatures in the settee area were 10+ above ambient with just the freezer running. This was with the inverter located in the vicinity powering only the freezer. I suspect with the battery charger running full tilt they would be higher. With the vent box installed the ambient temps were only 1 degree above ambient. The temps in the condenser fins were several degrees lower as well. It was a hot weekend here in San Diego this weekend so it was a good test. There is a decent warm flow coming out of the 4" vent I installed just above the settee on the back wall.

All in it cost about $20 for the vent, coupler, some scrap plywood and a bit of 4" flex duct I had laying around. No external fan or power/wiring/relays were required.

I'm going to put this one in the win column.

 

[BruceK]

Ain`t convection a wonderful thing when it gets a chance to perform.
There looks to be a lot of Riviera design features in your Lindell 36, esp pic 1 in post 9.

 

[lwarden]

Ain`t convection a wonderful thing when it gets a chance to perform.
There looks to be a lot of Riviera design features in your Lindell 36, esp pic 1 in post 9.

Yes, the designer was "inspired" by the Riviera layout. I'd like to think they took those and made a better version in terms of the quality of the finished product. Not that there is anything wrong with a Riviera, we almost ended up with one, but the level of finish and quality of materials is no match IMO.