solar vents

[Talbot]

You can achieve a very good result using a computer fan installed into the vent trunking. It uses miniscule amounts of power, but provides a much higher air flow than the solar fans.

[Alan Wheeler]

I have to agree to the comment about the solar vents. I have two and I think they are a waste of time. They just don't last. You will achive as good if not better result from two Drade vents. The cowl's should be faced in two differing directions. Thus the wind will blow into one and be sucked out the other. It will move more air than those Solar vents ever will dream off moving.

[capt lar]

i'll try reversing one dorade and see if it helps with stuffy cabin. i am concerned that on a small foredeck, where people will step and lines will cross, having anything that protrudes is a negative.
capt. lar

[capt lar]

if that isn't enough.... talbot, sharp idea to put fan inside, perhaps at vent opening in head, and exhaust out, since this is the dorade i will try facing aft. are you saying the fans on "non-laptops" is 12 volt ? capt. lar

[GordMay]

Standard PC fans are 12VDC nominal.

ie: Radio Shack: http://www.radioshack.com/ carries 12VDC Computer Fans:

Micro Fan Catalog # 273-240 - ($12.99)
Air delivery: 7.7cfm ±10%
Voltage range: 10.2 - 13.8VDC - Rated current: 0.13A or 130mA (1.56 watts)

CPU Cooling Fan Catalog # 273-153 - ($19.99)
Air delivery: 23.3 CFM ±15%
Voltage range: 10.8 -13.2V DC, Rated current: 0.21A or 210mA (2.52W)

[capt lar]

great - no holes, easy mount, easy wire. nice solution.
capt. lar

[GordMay]

I'm not certain I understand what you mean by "no holes".
Where do you suppose the "outside" air is coming from, if not through a "hole" of some sort?

BTW: HVAC Engineers used to call it a "Fresh-Air" supply - but, perhaps reflecting the unfortunate reality, these days it's just called "Outside Air".

[Alan Wheeler]

I think he is meaning no holes in the Hatch. If he mounts a fan in a Dorade vent, it means no holes to have to cut. I think that's it.

That's what I did. One in the galley, one forward in the saloon. Circulates the air great, and is totslly invisible. No solar, but the draw is so small, it des not matter.

[capt lar]

wheels, you are correct - by using an existing vent i could simply create air flow mechanically thru use of fan when wind does not provide for free. i do not make new holes or add another obstruction to the deck.
capt. lar

[GordMay]

Capt Lar:
Gotchya good (now).
Adding fans to existing vents reduces the free-area of the vent, which reduces the 'free' (naturally aspirated) ventilation to negligible volumes, necessitating powered use of the fan at all times ventilation is desired.
Of course, when the fan is running, the ventilation will be significantly improved over the previous natural aspiration.
Plan the fan installation to include some kind of bug screen.
Also consider (2) opposing fans - supply & exhaust, which is more efficient than reliance on infiltration (or exfiltration).
Gord

[capt lar]

can do, gord. amps are low so that should be fine. i will be working on my batteries this winter, trying to upgrade and understand choices, so i look forward to asking for more help on the power end in a new thread. have other projects to complete first. did find the mystery leak - chock in an area of previous repair. surface moisture meters are great. help find trouble early.
capt. lar