In deep on my V17

Sumner · May 18, 2012

MrBill_FLL said:
not sure about that cooler, for the whole cabin..

Give it a try, but from my thermodynamics class I don't think it is going to do the job, but I have tried a number of projects that didn't meet expectations over the years and probably more in the future. Still learned something from all of them.

MrBill_FLL said:
...also check
http://forums.macgregor.sailboatowners.com/showthread.php?t=141195

Yep if you read that thread you will see that Ruth and I are big fans (

) of the fan route....

... more on our site here....

http://purplesagetradingpost.com/sumner/macgregor2/inside-31.html

Sum

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MrBill_FLL · May 18, 2012

in a previous racing life, I used the cool shirt and a similar device to your cooler, connected to my helmet. (forget the name, but just a AL coil in the cooler with forced air).

if you duct a hose right next to your face it will spot cool.... for a little while.

I have a few of the cheap wallyworld 12v truckers fans, (loud/hi amps), but moves the air enough to sleep.

-I think a (cool) solar shower after dusk will really help cool you down. -if you don't have one, I'd suggest it.

I can get 2 showers out of 3 gal, if you shut it off between wash /rinse.

-Oh, volvo does a bay race sat, and takes off sun... might be fun to watch that...

http://volvooceanracemiami.org/calendar-of-events/

-not sure if its off shore or in the bay... Heard they are based out of bayside...

cheers!

rgranger · May 18, 2012

So lets talk air conditioning... <evil grin>

I've been thinking a lot about this and it seems you all are also. Lately I've been considering three different lines of thought. The first (and least likely) is to buy one of those portable "individual" air conditioners with an exit port that looks a lot like a dryer hose. I'm thinking it would be nice to have when I tie up at a marina with electricity. But I don't do that very often... I like to anchor in a cove all by my lonesome. Fans... yeah got one of those but don't have an alternator on my outboard to charge the batteries so I don't use it much. I guess an alternator or more solar would be a logical upgrade... but what about heat exchanger and evaporative cooling?

I once saw a post that claimed that wrapping a beer can in a polar fleece sock and then wetting the fleece cooled the beer can down by 5 or more degrees in about 15 minutes... just from the evaporation effect. (it takes 5700 calories to evaporate one gram of water) The claim was that the polar fleece provided enough surface area to allow a significant evaporative effect (I have not verified this). So this got me thinking... Could you design a boom tent and/or forward deck mats out of fleece, lay it all over the boat in the evening and just hose down the boat before bedtime?... let the breeze cool you off through evaporation. I'm thinking of a good hard sweat for your boat. In theory it should work. You might look crazy (crazy like a fox) but if it works...:dance:

And then what about a simple heat exchanger. Have you guys every heard of anyone taking two simple radiators (get a junked one at the yard) and some one way valves and hose.... drop one radiator over the side of the boat and have your fan blow through the other? I'm thinking one of the primer bulbs like you use on the O.B. fuel line would be enough to get the fluid flowing and the one-way valves would keep it going in one direction. Expansion of the fluid on the hot end and contraction on the cool should keep it going...Geothermal....

Okay... so... tear it up and tell me why I'm a fool

Sumner · May 18, 2012

rgranger said:
....Okay... so... tear it up and tell me why I'm a fool

We cool our house in Utah with a cooler that works on evaporation only...

http://en.wikipedia.org/wiki/Evaporative_cooler

.... and it works great if the humidity is low. Where we live, mountain southwest, it is usually 5% to 20%. Just looked and it is 78 deg and 7% humidity at home as I write this. Here in the east it might work a little, but when the humidity is high, typical, it just is not going to be effective.

Your water heat loop just isn't going to cycle. If it did perpetual motion machines would be more than a myth

.

Spend your money on the low amperage fan on the page I posted a link to on our site above...

http://purplesagetradingpost.com/sumner/macgregor2/inside-31.html

.... For a day or two your battery will probably be fine. Past that add a 40/60 watt panel.

Also we bought 2 O2 Cool fans at Walmart the other day (around $16.00) and they move quite a bit of air and will run a number of hours on D cells or cut the adapter cord off and run on the boats 12 volt battery direct. I think they might not draw much at all on the low setting and move considerable air on that setting also. The adapter only puts out 1/2 amp max. so the fan draws less than that.

Good luck,

Sum

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Merlin Clark · May 18, 2012

Don't jump too soon guys, these things work. I built one, used a piece of that blue insulation foam fm Lowes as the top and a 12v truckers fan to push air into the box. The 2 vents were 1.5" pvc elbows to direct the cool.
Dropped 1 bag of gas station ice in it and stuck it in a black hardtop Wrangler in the middle of the afternoon here last summer. Cooled the jeep off and was still blowing cool air 3 hours later.
If you use some solid ice along with cubes it should last a good while.

Sumner · May 18, 2012

merlinuxo said:
Don't jump too soon guys, these things work.....

Guys use them at Bonneville, racing on the salt flats, to pump cool air to their helmets and I will also. I could see it working some in the jeep for a short perion, but to have any real effect on the volume of air inside of even a trailered sailboat is going to take a lot of ice and I don't think it will last all of that long. Maybe sitting right in front of the vent.

We have one of these running...

http://www.westmarine.com/webapp/wc...hanintel_google&ci_src=14110944&ci_sku=752457

... in the Endeavour right now as we are living/working on her up on stands here in Florida and I think it is only lowering the temps 5-7 degrees during the day. It does make a difference and the interior is a lot larger volume wise than a Mac, but still think you would need lots of ice to make a difference over any length of time.

I found one source that says a 25 lb. block of ice would absorb about 3600 BTU's and the air conditioner above is rated at 6720 BTU/hr. According to that a 25 lb. block of ice might be about the same as the air conditioner running for 30 minutes. I'm up to the fact that my math might be off

,

Sum

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Merlin Clark · May 19, 2012

Sumner said:
Guys use them at Bonneville, racing on the salt flats, to pump cool air to their helmets and I will also. I could see it working some in the jeep for a short perion, but to have any real effect on the volume of air inside of even a trailered sailboat is going to take a lot of ice and I don't think it will last all of that long. Maybe sitting right in front of the vent.

We have one of these running...

http://www.westmarine.com/webapp/wc...hanintel_google&ci_src=14110944&ci_sku=752457

... in the Endeavour right now as we are living/working on her up on stands here in Florida and I think it is only lowering the temps 5-7 degrees during the day. It does make a difference and the interior is a lot larger volume wise than a Mac, but still think you would need lots of ice to make a difference over any length of time.

I found one source that says a 25 lb. block of ice would absorb about 3600 BTU's and the air conditioner above is rated at 6720 BTU/hr. According to that a 25 lb. block of ice might be about the same as the air conditioner running for 30 minutes. I'm up to the fact that my math might be off ,

Sum

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I don't know the theory, just what I experienced Sum.
Do you guys have shade rigged on the Endeavor? A poly tarp boom tent and shade over the fore deck makes a huge difference wiht the interior temps. I rig my tents/shade with 1 1/2" PVC pipe spreaders so that I can walk under them, not just draped over the boom and tied to the lifelines.

Merlin Clark · May 19, 2012

Sumner said:
We have one of these running...

http://www.westmarine.com/webapp/wc...hanintel_google&ci_src=14110944&ci_sku=752457

Sum

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We've had a couple of those Cruiseair jobs too and found that they really don't have any more going for them than a $100 wally world window banger. Except costing 400% more.
Oooops! Just looked at the price! HOLY %$*&! Last one of those I bought was about 500 clams, looks like they're are REALLY hosing down the newbys these days! Must have replaced all the metal and aluminum with unobtainium!

Sumner · May 19, 2012

merlinuxo said:
We've had a couple of those Cruiseair jobs too and found that they really don't have any more going for them than a $100 wally world window banger. Except costing 400% more.
Oooops! Just looked at the price! HOLY %$*&! Last one of those I bought was about 500 clams, looks like they're are REALLY hosing down the newbys these days! Must have replaced all the metal and aluminum with unobtainium!

Yep, they are too expensive for us. It came with the boat, we wouldn't of bought it. I thought about selling it until I asked in a West Marine what I might get out of a used one. He said about $300.00. I thought that is a big difference vs. the cost of a new one sitting on their show-room floor, so we just held onto it. It came with one of the hatch covers and I see that they get close to $300 for just that cover. What a rip-off

.

So far it makes it bearable in the boat, but I don't know about a month from now. Then we will head home to where you have to sleep under the covers every night with just the window open. We only run the cooler there some days and for just part of the day.

If it dies we will buy a cheap one like you mentioned. We won't be using it out on the water, just in the yard while we are up on stands. We will put it in the storage unit when we go out.

No tent over the boat at this time as we are working all over it. If an ice block cooler works then I can't argue that fact

,

Sum

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Texrob · May 21, 2012

I was thinking one could drop a pump overboard below a thermocline or two to draw cool water. On my lake that would be about 15 to 30 feet. Pump the water thru something like a heater core and draw air across it. Humidity should condense removing moisture from the cabin and should blow cool air.

Any thoughts?

Merlin Clark · May 21, 2012

Texrob said:
I was thinking one could drop a pump overboard below a thermocline or two to draw cool water. On my lake that would be about 15 to 30 feet. Pump the water thru something like a heater core and draw air across it. Humidity should condense removing moisture from the cabin and should blow cool air.

Any thoughts?

Could use a small bilge pump and discharge over the side.
"Cool idea".

rgranger · May 21, 2012

Sumner said:
Your water heat loop just isn't going to cycle. If it did perpetual motion machines would be more than a myth .

I don't know how practical it would be but my idea is quite sound and thoroughly routed in thermodynamics. (I teach the course).

I've attached a crude schematic of what I have in mind... You would need to pick a liquid with a large thermal expansion coefficient (ethanol comes to mind as a decent choice; b = 1120). And you would need to make absolutely certain that you could bleed ALL of the gas out of the loop. So as the ethanol was warmed in the "in cabin" heat exchanger it would expand, and the the one-way valve on the left side of the diagram would prevent it from flowing to the left, so as it expanded it would have to flow to the right. As it flowed to the right it would displace ethanol on the other side of the second one-way valve; forcing fluid into the cool-side (overboard) heat exchanger. This displaced ethanol would flow through through the loop and eventually back through the one-way valve on the left side of the diagram.

It is not a perpetual motion machine. The input of energy is thermal... It is a thermal engine machine a.k.a. a Carnot Cycle (the basic math of all internal combustion engines) and the math and theory is well established. The efficiency of a Carnot Cycle is given by....

n = 1 - T(cold)/T(hot)

I also don't think it would cost a lot to make one... I did a quick google search for heating cores and they are $20 on line. I don't know what a one-way valve would cost but in order for this to work the valves would have to be efficient and not restrict the flow very much. and the tubing would need to be robust at least to the point at which the tubing would not expand before forcing the fluid through the one-way valve. You would also need to be able to deign a bleed valve and maybe a port through which you could inject ethanol as you were bleeding the line.

The other idea posted here of cycling the fluid with a bilge pump should work but your are right back to the problem of power consumption. If you can afford that much power, you might as well run an AC unit.

MrBill_FLL · May 21, 2012

I looked at heat exchangers, and evaporation coolers. they work in the Dry west, but have not heard any positive results in humid south.

(check out burningman.org websites on this type stuff... a very creative bunch.)

a honda 2000 will run a 5000 btu window shaker. but I have never run it at sea, due to 1) CO, 2) where to put it so it doesn't start a fire with the exhaust .

but I did run it on the trailer for 30 min...

-Hwood, cutting the cabin down will help. ->shower curtain. but I would think about a fans.

-if you have enough amps, some electric radiator fans move lots of CFM... but at hi amp costs.

also block ice... a 2 liter cut off the top and put in a freezer lasts a long time... 4 of those might even go all night.

-GL!

Texrob · May 21, 2012

The pump would not need to be that powerful, just enough to keep the water flowing. Something like a small 12v fountain pump. Just enough to cool the core. Then a in line fan like the one Atwood makes. I have an extra battery just for running a fan at night that should last overnight.

rgranger · May 21, 2012

Texrob said:
The pump would not need to be that powerful, just enough to keep the water flowing. Something like a small 12v fountain pump. Just enough to cool the core. Then a in line fan like the one Atwood makes. I have an extra battery just for running a fan at night that should last overnight.

Yeah I think you are right... I did a google and found a few options.... This one looks good.

http://www.virtualvillage.com/solar...dium=shcomp&utm_campaign=google_shopping_feed

Sumner · May 21, 2012

rgranger said:
I don't know how practical it would be but my idea is quite sound and thoroughly routed in thermodynamics. (I teach the course).

Sorry, but I made the assumption from your first post...

rgranger said:
..Expansion of the fluid on the hot end and contraction on the cool should keep it going...Geothermal......

...that the fluid you were talking about was water :cry: and I could not see that expanding and contracting.

With gases/liquids as in a frig type setup are you going to see enough temperature differential to make it work like the compressor in a frig?

I guess give it a shot and see if it works,

Sum

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In deep on my V17

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