We don't have salt water up here, but we do have the highest incidence of pancreatic cancer in the country. We3ll, the great lakes do in general, not just the Lake Erie area. But, i was interested in getting out of here and going to the Caribbean for a few years. That means I will need water. So, is a reverse osmosis unit a ro unit? Are they all the same, and the ones for the marine environment just marked up so high because it says marine on the package? The Costco unit says it will remove salts. I know this means more than just sodium chloride, but that is also included in what it will remove. So, for under $400, I can get a Costco unit and save $4500 over the ohter units I find at 170 gallons per day. Or am I missing something?
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what is the difference?
RO is essentially filtration - haven't seen the Costco ad so don't know what the difference is
RO is essentially filtration - haven't seen the Costco ad so don't know what the difference is
what would be cool
Is if somebody built a unit that would take in raw water, split the Hydrogen from the Oxygen, re-combine the hydrogen with oxygen, and now you have crystal clear water. The electricity used to split the Hydrogen from Oxygen can be supplied by the electricity generated by combining them later. It may not be a pure 100% self sufficient, but I bet it would use less electricity then a normal water maker.
Is if somebody built a unit that would take in raw water, split the Hydrogen from the Oxygen, re-combine the hydrogen with oxygen, and now you have crystal clear water. The electricity used to split the Hydrogen from Oxygen can be supplied by the electricity generated by combining them later. It may not be a pure 100% self sufficient, but I bet it would use less electricity then a normal water maker.
Franklin' There is your opportunity to make
a million. The results of reverse osmosis depends upon the pore size of the filter. To desalinate water the filter must pass H2O but block NaCl and the many other salts in sea water. Most of the So-called reverse osmosis units sold to clean water can filter virus and bacteria but can not remove inorganic salts.
a million. The results of reverse osmosis depends upon the pore size of the filter. To desalinate water the filter must pass H2O but block NaCl and the many other salts in sea water. Most of the So-called reverse osmosis units sold to clean water can filter virus and bacteria but can not remove inorganic salts.
Pressure vs. salt concentration
The higher the salt concentration the higher the pressure needed to push water through the membrane leaving the salt behind. Household units like sold at Costco depend on the typical municipal water pressure which is sufficient for removing salts from tap water. However at sea there is no high pressure water supply from city taps, the pressure has to be created by a pump and has to be much higher to remove the higher concentrations of salt in sea water plus a much stronger membrane. This why these units cost so much and require a lot of battery amps.
The higher the salt concentration the higher the pressure needed to push water through the membrane leaving the salt behind. Household units like sold at Costco depend on the typical municipal water pressure which is sufficient for removing salts from tap water. However at sea there is no high pressure water supply from city taps, the pressure has to be created by a pump and has to be much higher to remove the higher concentrations of salt in sea water plus a much stronger membrane. This why these units cost so much and require a lot of battery amps.
I didn't know....
That most boats already have a watermaker.... Was trying to find out the exact process it takes to seperate the Hydrogen and also the combining when I read that if you freeze saltwater, the salt falls to the bottom. So if you ever find yourself without fresh water but still have the freezer working, put some saltwater in there.
That most boats already have a watermaker.... Was trying to find out the exact process it takes to seperate the Hydrogen and also the combining when I read that if you freeze saltwater, the salt falls to the bottom. So if you ever find yourself without fresh water but still have the freezer working, put some saltwater in there.
RO
There are 3 types of RO. PAM, CET, TFC. CET and TFC are for freshwater use. PAM is for saltwater or freshwater use and is quite expensive(starts @$800+) and must be kept in a preservative when not in use. CET use has fell off since TFC filter prices have come down. TFC is what the COSTCO filter is. I have tropical fish and use it to soften the hard water we have here in houston. The home units will produce 10 to 15 gallons a day running off of normal water pressure. The PAM are either hand operated or have their own builtin pressure pump. They all produce wastewater sometimes as high as 4 gallons to every 1 gallon produced. CET cellulose acetate TFC thin film composite PAM ?
There are 3 types of RO. PAM, CET, TFC. CET and TFC are for freshwater use. PAM is for saltwater or freshwater use and is quite expensive(starts @$800+) and must be kept in a preservative when not in use. CET use has fell off since TFC filter prices have come down. TFC is what the COSTCO filter is. I have tropical fish and use it to soften the hard water we have here in houston. The home units will produce 10 to 15 gallons a day running off of normal water pressure. The PAM are either hand operated or have their own builtin pressure pump. They all produce wastewater sometimes as high as 4 gallons to every 1 gallon produced. CET cellulose acetate TFC thin film composite PAM ?
Ah....
So you take in raw water, apply electricity that seperates the Hydrogen from the oxygen, feed that into a fuel cell which will generate heat, water, and electricity. So your watermaker is also your water heater. This sounds way too easy...that is if the fuel cell doesn't cost an arm and a leg.
So you take in raw water, apply electricity that seperates the Hydrogen from the oxygen, feed that into a fuel cell which will generate heat, water, and electricity. So your watermaker is also your water heater. This sounds way too easy...that is if the fuel cell doesn't cost an arm and a leg.
try this page
I found this site which explains RO. I also contacted several manufacturers. The main difference that I see is price and volume, which are directly related. The more water per day, the higher the cost.
I found this site which explains RO. I also contacted several manufacturers. The main difference that I see is price and volume, which are directly related. The more water per day, the higher the cost.
her is what I found
It appears as thought the differnece is volume/price and water pressure. The water pressue can be taken care of with a good water pump on board. The other is volume. The mare GPD or Gallons Per Day the unit makes, the higher the cost. If the related like comes out, it has a chart to show what RO does.
It appears as thought the differnece is volume/price and water pressure. The water pressue can be taken care of with a good water pump on board. The other is volume. The mare GPD or Gallons Per Day the unit makes, the higher the cost. If the related like comes out, it has a chart to show what RO does.
Franklin, NO! You DON'T separate H2 and O2
with a RO unit. A RO unit is just a VERY VERY VERY fine filter (called a semi-permeable membrane) that filters sodium and chloride ions from water molecules. IT DOES NOT produce hydrogen and oxygen by the electrolysis of water followed by recombination to make fresh water. It takes high pressure (on the order of 1,000 PSI or more to force the water through the filter membrane to produce reasonably pure water on the low pressure side, and a more concentrated salt solution on the high pressure side of the membrane. It takes a lot of pressure to do this because the pure water really wants to dilute the concentrated brine solution by flowing back through the membrane to produce equal concentrations of salt on both sides of the membrane. The higher the concentration of brine on one side of teh membrane is with respect to the concentration of brine on the other, the higher the force is trying to equalize the concentrations. This force is called Osmosis, and is the opposite of what we want, so we need to put energy into the system to to work against this osmotic pressure. As a side note, the electrolysis of salt water will produce chlorine gas, hydrogen gas and sodium hydroxide, not hydrogen and oxygen (this is how most of the chlorine and sodium hydroxide is produced industrially).
with a RO unit. A RO unit is just a VERY VERY VERY fine filter (called a semi-permeable membrane) that filters sodium and chloride ions from water molecules. IT DOES NOT produce hydrogen and oxygen by the electrolysis of water followed by recombination to make fresh water. It takes high pressure (on the order of 1,000 PSI or more to force the water through the filter membrane to produce reasonably pure water on the low pressure side, and a more concentrated salt solution on the high pressure side of the membrane. It takes a lot of pressure to do this because the pure water really wants to dilute the concentrated brine solution by flowing back through the membrane to produce equal concentrations of salt on both sides of the membrane. The higher the concentration of brine on one side of teh membrane is with respect to the concentration of brine on the other, the higher the force is trying to equalize the concentrations. This force is called Osmosis, and is the opposite of what we want, so we need to put energy into the system to to work against this osmotic pressure. As a side note, the electrolysis of salt water will produce chlorine gas, hydrogen gas and sodium hydroxide, not hydrogen and oxygen (this is how most of the chlorine and sodium hydroxide is produced industrially).
That's not what Franklin said
Re-read his posts. He was speculating about seperating the hydrogen and oxygen from seawater, then recombining them to make fresh water. Franklin also mentioned fuel cells, since the byproduct of their electricity generation is water. I believe most of his discussion is mainly tongue in cheek, but has some validity, just isn't affordable, or would require too much equipment to stow on a cramped sailboat. I also did some research on the freezing of saltwater, and again Franklin is correct. Keep them neurons spinnin' Franklin!
Re-read his posts. He was speculating about seperating the hydrogen and oxygen from seawater, then recombining them to make fresh water. Franklin also mentioned fuel cells, since the byproduct of their electricity generation is water. I believe most of his discussion is mainly tongue in cheek, but has some validity, just isn't affordable, or would require too much equipment to stow on a cramped sailboat. I also did some research on the freezing of saltwater, and again Franklin is correct. Keep them neurons spinnin' Franklin!
About the only thing I know....
About the only thing i know about RO units from sailboat owners and also from the larger units used offshore on the oil and gas platforms is that they are ALL very high maintenance items.You just cant turn it off and leave it. The salt crystallizes and forms a solid mass and jams the whole works. But on the plus side, IF properly maintained, they are fairly reliable. I would like to have a unit, but not budgeted for it in the near future. Right now I will have to opt for 'water conservation'. Tony B
About the only thing i know about RO units from sailboat owners and also from the larger units used offshore on the oil and gas platforms is that they are ALL very high maintenance items.You just cant turn it off and leave it. The salt crystallizes and forms a solid mass and jams the whole works. But on the plus side, IF properly maintained, they are fairly reliable. I would like to have a unit, but not budgeted for it in the near future. Right now I will have to opt for 'water conservation'. Tony B
Not all 'RO' units are the same....
Standard Reverse Osmosis Membranes are of extremely low retention (Molecular weight cut-off - Daltons). What the Costco unit is is probably a very open porosity and much higher molecular weight cut off than whats normally found in RO, therefore the separation efficiency is not going to be 'very much'. Since the Costco unit is a 'dead-end' (not tangential flow as is standard RO) it will plug quickly and with little total throughput of influent water in comparison to a 'true RO' where the flow is tangential ACROSS the membrane (... a few % of 'permeate' going through the membrane). Such 'dead end' RO systems are very costly to operate when you compare the amount of water produced versus the cost of membrane replacement. When looking at a RO unit compare the "total cost" of operation versus total gallons output.
Standard Reverse Osmosis Membranes are of extremely low retention (Molecular weight cut-off - Daltons). What the Costco unit is is probably a very open porosity and much higher molecular weight cut off than whats normally found in RO, therefore the separation efficiency is not going to be 'very much'. Since the Costco unit is a 'dead-end' (not tangential flow as is standard RO) it will plug quickly and with little total throughput of influent water in comparison to a 'true RO' where the flow is tangential ACROSS the membrane (... a few % of 'permeate' going through the membrane). Such 'dead end' RO systems are very costly to operate when you compare the amount of water produced versus the cost of membrane replacement. When looking at a RO unit compare the "total cost" of operation versus total gallons output.
franklin's amazing machine
I'm no physicist, but I think Franklin just proposed the chemical equivalent of a perpetual motion machine. Not that I wouldn't buy one if he could get it working.
I'm no physicist, but I think Franklin just proposed the chemical equivalent of a perpetual motion machine. Not that I wouldn't buy one if he could get it working.
For Hydrolysis yoou need pure water
For hydrolysis you are adding electrons to oxygen which then becomes O2 and hydrogen becomes H2. The problem is that seawater has lots of other ions that will accept electrons most notably chloride which becomes chlorine. So for efficent hydolysis you have to start with firly pure water. But why go that far??? Distillation will purify water and takes a lot less energy. Solar stills have been around for a long time. Many of us have diesel engines. With a little rigging the heat from our diesels could be used to make a still. Rig a heat exchanger to the exhaust manifold. As others have mentioned RO to purify freshwater is easier than trying to make freshwater from seawater. The osmotic pressure that you have to overcome is much greater.
For hydrolysis you are adding electrons to oxygen which then becomes O2 and hydrogen becomes H2. The problem is that seawater has lots of other ions that will accept electrons most notably chloride which becomes chlorine. So for efficent hydolysis you have to start with firly pure water. But why go that far??? Distillation will purify water and takes a lot less energy. Solar stills have been around for a long time. Many of us have diesel engines. With a little rigging the heat from our diesels could be used to make a still. Rig a heat exchanger to the exhaust manifold. As others have mentioned RO to purify freshwater is easier than trying to make freshwater from seawater. The osmotic pressure that you have to overcome is much greater.
Distillation
First, I would like to say my little experiment didn't work all that well. I took a little salt water and put it in ice cube trays and froze it overnight. I took the cubes out and rinses the salt off and then put them in a glass to melt. The melted water still had some salt in it. I guess for it to work correctly, it has to be a larger body of water; icecube trays don't work. As for Distillation, that does seem to be better. I used to have an Icetea maker that you pour 2 quarts of water into and it would heat it to steam, cool off into a cup with tea bags that would then flow the tea water into a jug (still I guess). It only took about 5 minutes to do 2 quarts. Sure, it takes juice to do that, but I do have a generator on board, so all I need to do is to buy that ice tea maker (pretty cheap). The problem with the engine is that it already has a heat exchanger rigged to keep the engine and exhaust cool.
First, I would like to say my little experiment didn't work all that well. I took a little salt water and put it in ice cube trays and froze it overnight. I took the cubes out and rinses the salt off and then put them in a glass to melt. The melted water still had some salt in it. I guess for it to work correctly, it has to be a larger body of water; icecube trays don't work. As for Distillation, that does seem to be better. I used to have an Icetea maker that you pour 2 quarts of water into and it would heat it to steam, cool off into a cup with tea bags that would then flow the tea water into a jug (still I guess). It only took about 5 minutes to do 2 quarts. Sure, it takes juice to do that, but I do have a generator on board, so all I need to do is to buy that ice tea maker (pretty cheap). The problem with the engine is that it already has a heat exchanger rigged to keep the engine and exhaust cool.
reply from the company making Costo's unit
I asked if the units can be used for salt water and she said "No" in an email response. So I am not sure if that means "no, you can't use it for salt water", or "no, you can't use it on a boat becuase there is no pressure", or "no, it is a 120 volt unit and a boat is 12". Just "no". How I think. I am a guy!! I want to get to the root of the problem.
I asked if the units can be used for salt water and she said "No" in an email response. So I am not sure if that means "no, you can't use it for salt water", or "no, you can't use it on a boat becuase there is no pressure", or "no, it is a 120 volt unit and a boat is 12". Just "no". How I think. I am a guy!! I want to get to the root of the problem.
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