Multi-Purposing your bilge fans-gctid351879

[Guest]

Hi all. One of my projects this winter is to change my heat pumps condenser from water to a dx air over condenser. the lake im on gets really warm and weedy atleast once a weekend the water inlet needs to be cleaned out (or atleast it feels like its that often) I'm in the process of building this condenser housing out of fibrglass. ill be using 2 4" bilge blowers for the all important ignition protected feature. my question is

Are there any codes that state that a bilge blower cant be impeded by say a condenser coil. total airflow will be about 250cfm. I'm hoping i can nix my existing bilge fan and multipurpose the new setup as my dedicated bilge fan.

Thanks for any input.

[Guest]

It is my understanding that the document "Construction Standards for Small Vessels" is the Canadian regulation for new construction boats in your size range. Table 6-1 specifies flow rating for confined engine space ventilation. As long as you can maintain this minimum CFM for your engine space I don't think it could matter what kind of restrictions are in the system.

These standards are for new construction. What you do with your own boat is your own business, but the logic behind most if not all of the regulations is sound, so it is in your own best interests to keep within the intent.

Without knowing all the details, it sounds like a good idea to me so far.

[2850Bounty]

Matt, a question for you:

During the heat of the day (when A/C is most needed), will the ambient air temperature be warmer than the ambient water temperature, or visa-versa?

Liquid contact for removing heat is far more efficient than air contact for removing the same BTU value.

If you're up for a refrigeration project, have you considered installing a thru-hull heat-sink condenser unit?

This replaces the air coil style condenser.

If enough air/water temperature differential, this thru-hull unit will usually be much more efficient.

No sea water pump..... no issues with filtering cooling exchange water..... no modified cooling fans...... no extra electrical circuitry.

It simply sits in the water at/near your draft dimension, and dumps heat into the water through natural convection (see 3rd image).

[Guest]

thats a cool system, and not far off from what 2 other refrigeration mechanics had suggested i do, where i build a heat exchanger and install it on the transom. with that system i was concerned about lifting out of the water while on plane for extended periods.

this thru hall condenser would definately fix that problem but i do beach my boat from time to time, i wonder if id plug that up since i usually beach on mud.

it seems to be sized for refrigerators. or fractional tonnage systems. that would help alot with not letting heat build up in the cabin in the first place.

[2850Bounty]

Yep!

The big boys use this type of condensor system for both refrigeration and A/C.

You are correct.... any heat dumped from this will not be in the cabin. Only that which the freon lines would produce.

The unit is tuff, so no worries about damaging it any more than damaging a true thru-hull tranducer.

As for debris..... if you beach "bow in", it should not be an issue, me thinks.