Alright, Brighter brains than I need to convince me this is a bad idea.
Ive been thinking of making an A/C unit with a car heater core as a heat exchanger with lake water pumped through it by a 12v pond pump hung off of the transom (noise considerations)
Our lake is generally cooler than the air and even when it warms up, 5' down is pretty cool. If I could find a quiet enough suirrel cage fan I could fit this under the cooler liner and put high velocity household directional vents. 1 facing fore and 1 aft. The waste water from dehumidification could be scavanged by the bilge pump with a float switch.
Rough estimate on cost at the local junkyard is about $20 for the car parts, $30 for new hosing and wiring $15 for 2 through hulls (Above water line) and the most expensive part is $30 for a submersible pond pump.
Why not??
Small boat A/C
Scott,
I'm with you here, why not try it...
As you know, there are thermal transfer issues that will greatly impact efficiency/effectiveness. There are at least two threads that discuss this in some detail. But, if it can just take the edge off, it would be worth it to me...
Rather than a submersible pond pump, which I've only seen in AC (alternating current) versions, I'm going to try a 12 vdc bilge pump...
If you use a bilge pump, you gotta make sure you get one that is sealed. Yes, they are all designed to work under water, but some actually achieve 'water-proof' by trapping air around electrically sensitive components. This might present problems if you just toss it over the side hanging there by a hose and power cable...
Another issue, is that your pump must have sufficient head capability. Yeah, this should apply to other things in our lives as well... But, the pump will have to lift the cool water all the way up to highest point in the system. The depth under the water can just about be subtracted, since water at 5 ft down is under 5ft of head pressure already. But, you are going to be lifting it several more feet, before it goes down into the cabin. Most pumps are rated for throughput at a specific lift distance (head). You want to make sure you'll get sufficient throughput at whatever lift it will have to make.
I'm with you here, why not try it...
As you know, there are thermal transfer issues that will greatly impact efficiency/effectiveness. There are at least two threads that discuss this in some detail. But, if it can just take the edge off, it would be worth it to me...
Rather than a submersible pond pump, which I've only seen in AC (alternating current) versions, I'm going to try a 12 vdc bilge pump...
If you use a bilge pump, you gotta make sure you get one that is sealed. Yes, they are all designed to work under water, but some actually achieve 'water-proof' by trapping air around electrically sensitive components. This might present problems if you just toss it over the side hanging there by a hose and power cable...
Another issue, is that your pump must have sufficient head capability. Yeah, this should apply to other things in our lives as well... But, the pump will have to lift the cool water all the way up to highest point in the system. The depth under the water can just about be subtracted, since water at 5 ft down is under 5ft of head pressure already. But, you are going to be lifting it several more feet, before it goes down into the cabin. Most pumps are rated for throughput at a specific lift distance (head). You want to make sure you'll get sufficient throughput at whatever lift it will have to make.
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They Theirs
- Captain
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Scott
The Canvas Air Conditioner
James Robert Turner wrote:
Lynn and Larry claim when it gets too hot, they put on a loose shirt and wet it down.
The Canvas Air Conditioner
James Robert Turner wrote:
Posted on Thursday, June 23, 2005 - 10:13 am:
Use this practical analysis to calculate your power requirements for cooling. Multiply the 120 volt AC Amps times ten to get 12 volt amps.
If a common window air conditioner uses 10 amps running, you will need 100 amps to keep a similar capacity DC system running. The Rankin cycle physics apply to either system. Whether you circulate chilled water or air, you will get similar efficiencies.
Since you live in (On) Puget Sound or Lake Washington, why not pump some cold water out of the bay or lake through a 1952 Buick Radiator and back overboard. Use an electric fan to circulate air though the radiator and around the cabin to be cooled. Or if the Buick radiator is too hoakey, pump the cold water though your heater system. Aside from some corrosion issues, it will work. If you can keep the coil temperature around 40 degrees and you will have reasonable results.
BTW, some homes in places where artesian wells exist, divert this well water though boxed auto radiators, over blown by fans, to cool their houses. If the water source is uphill from the house, they don't need pumps for the water. A great resource for information on this is Mother Earth News. (;^)
Jim
Lynn and Larry claim when it gets too hot, they put on a loose shirt and wet it down.
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Catigale
- Site Admin
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Well this is just plain wrong. The AC uses most of those amps to drive a big compressor, which compresses gas to run the cycle which makes it colder...etc The concept above, the heat is essentially dumped into cold water off the boat, so the only electrical use is that you need to move the water.If a common window air conditioner uses 10 amps running, you will need 100 amps to keep a similar capacity DC system running. The Rankin cycle physics apply to either system. Whether you circulate chilled water or air, you will get similar efficiencies.
Still,,,
Chip H did the analysis in a recent thread, and when I ran the numbers, I saw his point that this just wont be effective. It aint rocket science, but it is chemical engineering/thermo and WADR you need a heat exchanger capable of thousands of BTU/hr exchange - this isnt small change.
On edit: 5000 BTU probably overstates the heat exchanger needed in the last line
Last edited by Catigale on Fri Jan 13, 2006 6:50 am, edited 1 time in total.
AC and Red Green
You guys are great. These are great ideas, but I'm sorry I couldn't help of thinking of the Red Green show reading this thread. This might be a good place for more ideas for Mods. 
Check out www.redgreen.com
"The Handyman's Secret Weapon? Duct Tape" Maybe we could have a meeting at "Possum Lodge."
The Man's Prayer --- "I'm a man ... but I can change ... if I have to ... I guess ..."
jda
Check out www.redgreen.com
"The Handyman's Secret Weapon? Duct Tape" Maybe we could have a meeting at "Possum Lodge."
The Man's Prayer --- "I'm a man ... but I can change ... if I have to ... I guess ..."
jda
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Scott
- Admiral
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- Sailboat: Venture 25
- Location: 1978 Catalina 22 with all the Racing Goodies!! 4 horse fire breathing monster on the transom
Im not talking about refrigerating a side of beef, just pulling a little humidity out of the air and cooling the cabin before sleeping maybe. A full size car uses a heat exchanger at about 4x7" by 1/2" thick and cools at or slightly above freezing. This is generally way too cold for me. I can get a heater core at 12x12" by 1 1/2" thick and water in the 60's, if I can lower cabin temp form 110 to say 80 or 90 deg over a 1-2 hr period I would feel like I succeeded.
Doable- or not?
Doable- or not?
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Catigale
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That car AC is taking a much smaller volume from typically 90 to 60 F - I would guess a car AC pulls about 5 HP from the motor, which is 3.5 kW
The Freon in the AC is very cold - since the cooling effort is proportional to the temperature delta between the air and the Freon, running 60F water will have much less cooling effect than the Freon so you would need massive amounts of air to pass over the heat exchanger
I dont think the math adds up on this one.
The Freon in the AC is very cold - since the cooling effort is proportional to the temperature delta between the air and the Freon, running 60F water will have much less cooling effect than the Freon so you would need massive amounts of air to pass over the heat exchanger
I dont think the math adds up on this one.
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k9piper
- Deckhand
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- Sailboat: MacGregor 26M
- Location: Lower Hudson River Valley N.Y.
Small boat A/C
Hi folks,
I'm just sitting here catching up on the posts on the topics on the site.
I have read a few ideas on the A/C topic and wanted to know if anyone has ever tried a product on the market that is refered to as a water cooler? I have seen these work on the Southern Border in the US as well as in many locations in Mexico.
What this thing will do is cool off an area as well as adding some moisture
to the area to be cooled. This is accomplished by putting water into a small holding tank and then taking that water and appling it to a filter that air passes over at a high rate of speed. We use fans to cool ourselves and by adding water to the picture we can add moisture and perhaps reduce the temp 10 maybe mopre degrees.
I am sure that you can get these at Wal-Mart, Target, Home Depot or Lows. I have seen them advertised in the papers as early as today but can't remember the store. They were around $140.00 and they were electrical powered.
Since most want to cool off at night perhaps this might be an option that is affordable. They are also portable and come in many sizes. I have even seen them as small as being placed on one's desk in the work place. I think I might check into it as we do not need constant A/C up her in the Hudson Valley of the Hudson River.
Another option would be to have rapid air movement in and out . That would have some cooling but far less. A/C sure would be nice but will you get out what you pay in cost?
The last option would be stay top side by the cooler and drink yourself cool...hum...a Black and Tan would be nice anytime as would be some liquid grapes chilled to the T.
Come on summer and good by snow!
K9piper
I'm just sitting here catching up on the posts on the topics on the site.
I have read a few ideas on the A/C topic and wanted to know if anyone has ever tried a product on the market that is refered to as a water cooler? I have seen these work on the Southern Border in the US as well as in many locations in Mexico.
What this thing will do is cool off an area as well as adding some moisture
to the area to be cooled. This is accomplished by putting water into a small holding tank and then taking that water and appling it to a filter that air passes over at a high rate of speed. We use fans to cool ourselves and by adding water to the picture we can add moisture and perhaps reduce the temp 10 maybe mopre degrees.
I am sure that you can get these at Wal-Mart, Target, Home Depot or Lows. I have seen them advertised in the papers as early as today but can't remember the store. They were around $140.00 and they were electrical powered.
Since most want to cool off at night perhaps this might be an option that is affordable. They are also portable and come in many sizes. I have even seen them as small as being placed on one's desk in the work place. I think I might check into it as we do not need constant A/C up her in the Hudson Valley of the Hudson River.
Another option would be to have rapid air movement in and out . That would have some cooling but far less. A/C sure would be nice but will you get out what you pay in cost?
The last option would be stay top side by the cooler and drink yourself cool...hum...a Black and Tan would be nice anytime as would be some liquid grapes chilled to the T.
Come on summer and good by snow!
K9piper
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Chip Hindes
- Admiral
- Posts: 2166
- Joined: Mon Jan 05, 2004 6:13 am
- Location: West Sand Lake, NY '01X, "Nextboat" 50HP Tohatsu
I have read a few ideas on the A/C topic and wanted to know if anyone has ever tried a product on the market that is refered to as a water cooler?
Actually they are commonly referred to as evaporative or "swamp" coolers. Many people in the desert SW use them instead of "real" A/C, as they use much less electricity per BTU of cooling, and they have the benefit of adding mositure to air which is uncomfortably dry as well as hot. Unfortunately for most locations in the U.S. and particularly in those locations where you float a boat, they work best at an ambient humidity of 20% and below. Their usefullness declines rapidly with increasing humidity, and above about 35% humidity they don't work at all. LTDT (Lived there, done that).
Regarding the whole remiander of the thread, I don't know how many more times or different ways it can be said:
Your proposal won't work.
We've been through this whole discussion at least twice before. l know it's not what you want to hear, but it's the truth. The only way you're going to get cooling out of the water around your boat is to jump into it.
Or install a water source heat pump. That is the principle of several marine A/C systems. I believe about $3K and up, plus installation including at least one below the water line through hull. Very efficient compared to standard air source A/C, but you still need shore power, a 120VAC generator or mongo DC to AC inverter to run them.
Maybe we can try one more mind exercise: If what you're proposing were actually a good idea and had a prayer of working, even marginally, somebody would already be building and selling it, and the discussion would be only about how they were ripping us off for such a simple device and we cold do it way cheaper.
My 2 cents:
It could work given the right conditions, but wouldn't work in all conditions. If the water is cold enough and the ambient temperature and humidity is right, it would work.
Bottom line is, talking and theorizing won't prove anything. Somebody needs to take the bull by the horns and Do It!
Greg
It could work given the right conditions, but wouldn't work in all conditions. If the water is cold enough and the ambient temperature and humidity is right, it would work.
Bottom line is, talking and theorizing won't prove anything. Somebody needs to take the bull by the horns and Do It!
Greg
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k9piper
- Deckhand
- Posts: 36
- Joined: Sun Mar 27, 2005 5:48 pm
- Sailboat: MacGregor 26M
- Location: Lower Hudson River Valley N.Y.
small boat A/C
Folks ,
It was just a thought. I have not read about this before on the board. Sorry Chip for bringing up a topic that has been talked about so many times over.
I didn't think I was taking up peoples time by sharing a thought or idea. Guess I was wrong.
Sorry folks, from now on I'll try harder by checking deeper before I post.
K9piper
It was just a thought. I have not read about this before on the board. Sorry Chip for bringing up a topic that has been talked about so many times over.
I didn't think I was taking up peoples time by sharing a thought or idea. Guess I was wrong.
Sorry folks, from now on I'll try harder by checking deeper before I post.
K9piper
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They Theirs
- Captain
- Posts: 790
- Joined: Tue Dec 27, 2005 1:42 pm
k9piper,
Chips frustration was to the original topic of pumping water though a heat exchanger and get a cooling/dehumidifying system.
You shouldn't apologize for your post- it may be of benefit to someone in the right climate- like the southwest.
We Mac owners live in different climates and inexpensive setups may work one person but not another with different climate and water conditions.
We live in an area that has hot humid summers, the Washington DC area. I know someone that has 2 wells on his property that he uses to cool his house. Water is pumped from one well, though a heat exchanger located in the air handler, then discharges into the other well. The 55 degree groundwater cools and dehumidifies his house most of the summer. He does have an air conditioning system that will come on if needed- but he says it only comes on a couple times over the summer.
If you are sailing in an area that has thermoclines available, I think they could be used to acclimate the cabin.
A few years ago, I was on a canoe trip in the Cedar Lake area - close to Brent Ontario. Glass and bottles are not allowed in Algonquin Provincial Park, so we took Margarita mix and tequila. Tied a 100'string and weight to an aluminum fuel bottle, attached another string to a cork and plugged the bottle tight. Paddle out and drop the bottle over the side down to 50-60 foot level and pull the string to pop the cork. Retrieve the bottle and used the ice cold water to mix the Margarita.
Now I wouldn't do that in a lake in Ohio, but it worked for where we were at the time.
Greg
Chips frustration was to the original topic of pumping water though a heat exchanger and get a cooling/dehumidifying system.
You shouldn't apologize for your post- it may be of benefit to someone in the right climate- like the southwest.
We Mac owners live in different climates and inexpensive setups may work one person but not another with different climate and water conditions.
We live in an area that has hot humid summers, the Washington DC area. I know someone that has 2 wells on his property that he uses to cool his house. Water is pumped from one well, though a heat exchanger located in the air handler, then discharges into the other well. The 55 degree groundwater cools and dehumidifies his house most of the summer. He does have an air conditioning system that will come on if needed- but he says it only comes on a couple times over the summer.
If you are sailing in an area that has thermoclines available, I think they could be used to acclimate the cabin.
A few years ago, I was on a canoe trip in the Cedar Lake area - close to Brent Ontario. Glass and bottles are not allowed in Algonquin Provincial Park, so we took Margarita mix and tequila. Tied a 100'string and weight to an aluminum fuel bottle, attached another string to a cork and plugged the bottle tight. Paddle out and drop the bottle over the side down to 50-60 foot level and pull the string to pop the cork. Retrieve the bottle and used the ice cold water to mix the Margarita.
Now I wouldn't do that in a lake in Ohio, but it worked for where we were at the time.
Greg