BowieReefer84 July 13, 2012 July 13, 2012 Found this on a RC forum, and thought others may like this idea. I had never heard of this before. "The GPD ratings are for room temperature (~70° F). Colder water travels more slowly through the membrane, which reduces the output. If you have a high-GPD unit connected to your cold water line, that can be a problem. Here's a solution (from Marc Levenson): You want approximately 25' or 30' feet of tubing from the connection at the cold water running to the RO/DI unit. Fill a 5-gallon bucket with water, and coil the excess tubing in the bucket so it is submerged. Immerse a small aquarium heater and set it to 78° F. As the RO/DI unit kicks on, water in the tubing will be warmed up to 78° as well, since it processes rather slowly, and the membrane will be able to produce maximum output in the dead of winter." Cool idea!
icecool2 July 13, 2012 July 13, 2012 I've heard of this idea too. It's a cool idea, but I never did it because I've already got enough buckets of water to lug around without having to add a heater bucket too
treesprite July 14, 2012 July 14, 2012 I've heard of this idea too. It's a cool idea, but I never did it because I've already got enough buckets of water to lug around without having to add a heater bucket too LOL
F&Fmgr July 14, 2012 July 14, 2012 Found this on a RC forum, and thought others may like this idea. I had never heard of this before. "The GPD ratings are for room temperature (~70° F). Colder water travels more slowly through the membrane, which reduces the output. If you have a high-GPD unit connected to your cold water line, that can be a problem. Here's a solution (from Marc Levenson): You want approximately 25' or 30' feet of tubing from the connection at the cold water running to the RO/DI unit. Fill a 5-gallon bucket with water, and coil the excess tubing in the bucket so it is submerged. Immerse a small aquarium heater and set it to 78° F. As the RO/DI unit kicks on, water in the tubing will be warmed up to 78° as well, since it processes rather slowly, and the membrane will be able to produce maximum output in the dead of winter." Cool idea! Simple and cheap fix! thanks for sharing. Sean
Reefn July 14, 2012 July 14, 2012 Geez - Really - 5 gal buckets? That's a pain. Get a 50+ gal barrel (I use 65gal food grade), put an auto shut off valve and a fried heater in it (plugged in for winter only) and let it run. Plenty of warm RODI water when I need it! Great for all my tanks! Best...
Jon Lazar July 14, 2012 July 14, 2012 (edited) Sounds like a clever idea. Has anyone tried it and measured the temp of the water coming out to see if it works in reality? Edited July 14, 2012 by Jon Lazar
BowieReefer84 July 14, 2012 Author July 14, 2012 Geez - Really - 5 gal buckets? That's a pain. Get a 50+ gal barrel (I use 65gal food grade), put an auto shut off valve and a fried heater in it (plugged in for winter only) and let it run. Plenty of warm RODI water when I need it! Great for all my tanks! Best... I think you misunderstand. It is warming the input water before it goes through your ro/di unit. It is NOT saying use a 5gal bucket to store your water... hth
stankyd July 26, 2012 July 26, 2012 Very cool. I saw a similar DIY chiller running pipe through a freezer and back into a tank.
Chad August 2, 2012 August 2, 2012 My first thought here was "wow, the head loss in a 25' 1/4 tube is really high, that might cause a problem." So I ran some numbers... At the low flow rates (75 and 150 gpd) we see in an RO/DI system, it isn't a big deal with a drop of less than 1 psig. Cool. Full speed ahead!
Jon Lazar August 2, 2012 August 2, 2012 I would think that the contact time is too low, and the thermal transfer characteristics of RO/DI tubing too poor to have a big effect on the temperature. If only there were engineers in WAMAS clever enough to figure a theoretical value for something like that, and then run an experiment to verify...
Chad August 2, 2012 August 2, 2012 Use PEX tubing, it will work out fine Rough math says that with 25' of tubing and a flow rate of ~75 gallons per day through it, the whole volume of the line turns over every minute, so there is around a minute's worth of contact time. That's more than enough time (even at low heat transfer rates) for the supply temperature to go up significantly, though it would take me a bit to figure out a guess (my big book of heat transfer constants is at work). I suspect it's a reasonable amount and would put my money on a rise of ~50% of the difference. The real question here is whether the increased efficiency of the RO membrane is worth the extra complexity and cost of running another heater
DaveS August 3, 2012 August 3, 2012 Chad, did you assume 75gpd because its a 75gpd membrane? Remember, that's the output not input. I think the rule of thumb is 4:1 ratio of bad to good water. So we'd be talking 5x more water or 1/5th the contact time. Oops did the reactor just melt down?
Chad August 3, 2012 August 3, 2012 hah! Yep, totally a good point! Even more support to the efficiency vs. cost/complexity issue...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now