Warming RO water?
 

My RO feed water is freezing, just looking for some ideas on how to warm it up. I have heard of using a bucket with water and a heater in it, only problem is you would need alot of tubing for the water to have a chance to warm up, and with more tubing you lose pressure. Is there any other methods to warm the water?

Make RO in a bucket, with heate in it. One bucket at a time. Are you planing a large water change? Basically need a bucket large enough to hold all the water you want to change, or change the water one smaller bucket at a time

Are you talking top up or waterchanges? Either way...bucket with heater.

I dont warm for top-ups. But then, only using 1/2g for TU, added to sump, doesnt change tank temp

The only thing you can do is add a pump and make sure your pressure into your RO unit is 65 psi constantly. (if it is already then forget the pump)

It would cost you a lot more money to warm your feed water with a heater than it would to simply waste more water. (electricity is much more expensive than water)

One other possible option is to coil your RO feed tubing in your sump. This will cool your tank water as well as heat your RO feed water. You must be careful not to cool your tank water too much though otherwise your heater will run and you are back to square one.

You could always tap into you hot water feed line as put a valve and then take it to you RO aswell....this way you can add a little hot water to bring them temp up!

im not certain but im sure that i read your ro unit will work better with cold water then hot so dont tap your hot water line.

Richard

RO membranes are suppose to produce better around 77degrees water temp. I'm getting major condensation on all my RO lines, which has never happened before, so my water is very cold, which will cause you to lose performance. Right now I am getting around 80 psi to my membrane.

Correct they work best in that 25 degree Celcius temp range and the last time I checked the temp of the water coming out of my tap it was like around 16 degree's celcius

This might not work for everyone but I run my supply line through my sump.Being that I heat the water for the tank I figured why not use it. I also make sure I do a five minute flush of the membrane once a week. It seams to add to the life of my RO.

I like the sump idea, only problem is the distance from my RO to sump, would have to travel on the ceiling, then have alot of tubbing in the sump. Would I lose alot of pressure running 50 feet or more of tubing before the water even hits the RO unit?

I tried it with 1/4 RO line, lost a lot of pressure.

I now have 100 feet of 3/8 RO line ($12) and run it in a coil in the sump. It cools my tank and heats the water used for RO. My TDS went down, my fan over my sump runs a lot less, all good stuff.

I highly recommend it.:mrgreen:

Nigel you can always get a heater joint that attaches to your water line before it goes to your membrane. that hook on the copper pipe and its on a gauge to tell you how warm you want the water , works really good i havent tried one yet thou i may once i get back from over sea........

Mike were do you get those, or what are they called, just intrested in reading more on that.

The 3/8 line might be an idea. I'm going to keep checking around and see what I can rig up

Thanks everyone for your inputs

home depot , rona , home hard ware, I think that Cdn tire may have them too....

The 3/8 line is the way to go. You can easily feel the difference in water temp just by touching the in line and the out line with your hand.

If you can't find it for a good price, let me know. I can get it real cheap.

really the 3/8" makes that much of a difference in the water andthe membrane too or just the warmere water

how much pressure did you lose after running the 100 feet of 3/8 line?

I bought a gauge for my system.

I lost about 20 psi (when the system was running, same psi when it is stopped, of course) with the 1/4 inch line.

The 3/8 line has maybe a 1 psi pressure drop, so from 60 to 59 psi, if even that bad.

Don't do 1/4 line!!!!!!!!!!!!!!!!!!!!!

3/8 works perfect, absolutely perfect. The only problem is if you decide to make 100 gallons of water, then my tank drops about 5F in temp. But in normal use it is 100%.

Your pressure loss using a 1/4 inch line versus 1/2 should be almost the same. Being that friction loss is directly tied to flow rate it seems to me that the flow rate for an RO unit is very small. A 50 gallon per day RO unit delivers about .03472 gallons a minute. This translates to a very small pressure loss regardless of the size of your line.

Was running the 1/4" supply line through my sump for a while but abandon because of the pressure drop.

There is merit though in warming the RO. Cutting from here (Aqua-safe) "membranes are flow rated at 77F, 65 PSI and 200 TDS and for every 1F water temperature, the production rate will drop 1.6%"

Has anyone come up with more options for heating their supply water since this thread last posted? I just installed my new RO/DI and I was thinking of coiling about 10 feet of 1/4" supply line and attaching an 8W repti-therm heater to it.

Not sure if that will give me enough time to heat the water much...any thoughts?

Agreed, Definitely needs to be warm... There is a build thread I was watching on another forum, and the guy is in colorado and his RO in line was sooo cold that his RO was produing VERY little water... Was more of a drip that a constant flow.. I think it took him close to a full week to fill 140G tank.

Since this last came up I have taken the line out of my sump. It was just too hard to keep the tank temp up. I looked around for a constant heat supply and decided that my MH ballast would work just fine. My ballasts have the metal fins for cooling. I just ran the water line back and forth under the ballasts. I'm not sure how much my line temp has risen but it's definately warmer to the touch. And it keeps my ballasts a little cooler as well so thats a bonus. Of course it only works during the day but what the heck, it's free heat.:biggrin:

Running through the ballast...a very interesting idea for the future for me. Unfortunately, RO is no-where near my tank right now...so I'm still looking for good ideas.

Tagging along with this one as well since my first RO had very poor performance and I was looking for ways to heat the input. I know the industrial RO unit at the local Exxon/Mobil plant uses steam to pre-heat their lines and the performance is supposedly much better the hotter it is. I was going to use a heat tape (used to keep pipes from freezing) and wire in my own thermostat but looking at my electric bill decided against it:mrgreen:

I ended up doing a 100' of 3/8" RO line and put it in my sump. And worked perfect. I haven't checked the temp lately of the water entering the RO but last time I checked it was around 72-73F. I also did not lose any pressure going into my RO unit.

In keeping along the lines of using the reptile heater...I see zoo med has a heater cable (11.5') at only 15 watts. I could tape this to the supply line and I would get at least 6' of warmer cable. If no-one has any other suggestions...I think this is what I will try.

But, does the sump/tank loose any temp? Personally, with the amount of waste water made, even with the benifits of warmer water. I would think the cost of the electricity to heat the incoming water to the membrane would outweigh the benifits because most of the warmed water just goes down the drain.

Sure it cools the tank.

But if you are like most of us, it is excess heat you need to get rid of. My tank has a total of about 330 gallons, and the lowest I can get my tank down to is about 80F. I have no heaters in my tank.

well, ya if your that warm I guess LOL. It's cold here, my heaters on :D