Condensor fan speed control?

[phantomracer]

Installed a frigoboat refrigeration system in our boat. Working great...however, wifey is unimpressed with the fan sound!

Is there any way to add a speed control to the fan for night use. I don't mind it taking longer to cool, its the noise level I would like to control.

Any ideas?

[DeepFrz]

You don't say now its ducted or to where or if it is ducted but one thing you could try is to line the box with sound absorbing material.

[phantomracer]

the output of the fan is right into the cabin..

[colemj]

Maybe change the fan? When our fan went, I replaced it with a SilentX computer fan and was very surprised at the noise difference. The SilentX computer fan is completely silent - you cannot hear it when you have your head right next to the compressor and it turns on.

Mark

[sailnow2011]

Fan noise is directly related to air flow.
If the fan is more quiet less air will move, and you may overheat the compressor or controller. This would lead to an early failure. If you are OK with that, go for it.
We will be installing a louder fan on ours for longer life.

[phantomracer]

Originally Posted by colemj

Maybe change the fan? When our fan went, I replaced it with a SilentX computer fan and was very surprised at the noise difference. The SilentX computer fan is completely silent - you cannot hear it when you have your head right next to the compressor and it turns on.

Mark

did consider changing the fan..was looking at some.. might do that if I cant figure this out.

[phantomracer]

Originally Posted by sailnow2011

Fan noise is directly related to air flow.
If the fan is more quiet less air will move, and you may overheat the compressor or controller. This would lead to an early failure. If you are OK with that, go for it.
We will be installing a louder fan on ours for longer life.

The fan is the condenser fan. would be no different if we went south and the boat was a lot hotter than it is here in the north east US. There is no fan on the compressor or anything else.. The other units (keel and water cooler versions) dont have fans to cool the compressor or electronics.

I would like to reduce the airflow just for night use..if the fan is noisy..so is the wife.. this would make both quieter!!

[phantomracer]

Here is a pic of the unit. The fan is blowing right into the cabin.

refrigeration works great! So far the Efoy fuel cell has been able to keep up with it without a problem.

[colemj]

Originally Posted by sailnow2011

Fan noise is directly related to air flow.
If the fan is more quiet less air will move, and you may overheat the compressor or controller. This would lead to an early failure. If you are OK with that, go for it.
We will be installing a louder fan on ours for longer life.

Noise is related to more than just airflow. The number of blades, the shape of the blades, the bearings used and other design aspects also impact noise level.

The replacement fans I installed not only had a larger flow rating than the OEM ones being replaced, they also had a higher flow at pressure rating - which means that they keep a higher flow when pushing or pulling against a restriction (the condenser coils in this case). Overall, I upgraded the cooling on our compressor while decreasing the noise.

Mark

[colemj]

Your current Bi-Sonic fan has a noise rating of 48db, which is quite loud for a fan. Our replacement SilenX is rated at 15db.

However, your fan is rated at 88cfm, while our SilenX is rated at 74cfm. The OEM fan on our compressor was only rated at 68cfm.

The difference between 88cfm and 74cfm shouldn't be an issue in your application because you actually have a good installation where the cooling air is not recirculated inside a small enclosed compartment like many installations.

Mark

[a64pilot]

I assume your box insulation is pretty good, if so just turn the thing off when you sleep, it ought to stay cold overnight with the door closed.

[Anna Sail]

Originally Posted by colemj

Your current Bi-Sonic fan has a noise rating of 48db, which is quite loud for a fan. Our replacement SilenX is rated at 15db.

However, your fan is rated at 88cfm, while our SilenX is rated at 74cfm. The OEM fan on our compressor was only rated at 68cfm.

The difference between 88cfm and 74cfm shouldn't be an issue in your application because you actually have a good installation where the cooling air is not recirculated inside a small enclosed compartment like many installations.

Mark

Mark's advice sounds well informed; well worth a try. Proof will be if the change in fan at all effects the results you are currently getting with your Frigoboat system - with the replacement fan, is your system still maintaining the set point of your box at the same or less power consumption? The fan simply removes the heat from the refrigerant. If not enough heat is removed, then your box temp will rise and your compressor will work harder as the thermostat will keep calling for cooling. If the replacement fan doesn't work, you'll know soon enough and can switch it back to the original fan.

[phantomracer]

Originally Posted by a64pilot

I assume your box insulation is pretty good, if so just turn the thing off when you sleep, it ought to stay cold overnight with the door closed.

hehe, the boat is a 1968 with the original ice box.. im not going to assume it is that good When I drilled through the side to run the cables/pipes, there was a decent amount of foam insulation, not as much as modern boxes, no doubt.

I did think about shutting it off overnight, and might do that to keep the wife quiet til I can try another fan.

[colemj]

Just for perspective, these fans cost <$15, so there isn't much monetary risk: SilenX EFX-12-15 Case Fan - Newegg.com

Mark

[phantomracer]

Originally Posted by Anna Sail

Mark's advice sounds well informed; well worth a try. Proof will be if the change in fan at all effects the results you are currently getting with your Frigoboat system - with the replacement fan, is your system still maintaining the set point of your box at the same or less power consumption? The fan simply removes the heat from the refrigerant. If not enough heat is removed, then your box temp will rise and your compressor will work harder as the thermostat will keep calling for cooling. If the replacement fan doesn't work, you'll know soon enough and can switch it back to the original fan.

will try a quieter fan as it is cheap/easy. It can't be worse!

The frigoboat controller i got was their smart controller, which tends to run the compressor slower but for a longer time to conserve power...I thought the controller was the fan speed controller.. of course its not, now I have a duhhh moment..

was reading on the quietx fans, most are saying the 120mm quietx fans are louder than they expected (no doubt a LOT quieter than what i have) but still pretty quiet.

Was going to also build a box for in front of the fan output and line it with batt insulation as a muffler, as a first line of defense, for when we are sleeping (the berth pulls out above the compressor/fan), so it wont be in the way.

I think the quieter fan should work fine. will get some benchmarks from what I have and then try the quieter one.

I assume the fans, made for computers , have standard computer plugs on them and will have to cut them off. I assume it will be logical how to hook up the replacement one?