Question about RO/DI efficiency.

[apw63]

I am new to the hobby. I have heard that you can make an RO/DI system more efficient by tapping both the cold and hot water supply. Instead of running just cold water it would be running warm water through the RO/DI. The theory I heard was that it opens up the pores in the RO membrane. Does this sound correct? I would think by opening up the pores you would make it less efficient. If anyone has any ideas I would like to hear them.

Thank you
Andy

 

[sage_commander]

You'll get plenty of replies on this, but my understanding is that a RO/DI system runs most optimally at about 70 deg F. If the incoming water is too cold you will have much more waste water.

HTH

 

[Nano Chris]

I have read that if you use hot water, there is higher TDS (total dissolved solids) in it and it would shorten the life of your filters, but then how would one run cold water at 70 deg F, if you cant use hot water....

 

[Doahh]

77* F is the optimum temperature for an RO-DI Unti

 

[drummereef]

You should only tap the cold water supply.

 

[Travis L. Stevens]

The theory I heard was that it opens up the pores in the RO membrane.

If the theory is correct, then this is the last thing that you want to do. Larger pores would mean that more dissolved solids can get through. You want the least amount possible.

 

[AZDesertRat]

Temperatures much over 90 degrees damage the membrane. Its very hard to temper or regulate the temperatures when feeding from both hot and cold when we are talking about such low flow rates. Some coil a buch of tubing in a bucket of water with a heater in it but if you do the math it takes way more BTUs to heat the water than is practical. Colder water is only one of the things that has an effect on output. You can compensate for cold water by increasing the pressure with a booster pump if you do not have sufficient pressure already.

 

[apw63]

Thanks for the info!

I tested my cold water temp, and straight out of the tap it is 72 F. My RO/DI system only produces around 4 gph. I think at that rate of production the water temp should stay around 70 F. If I let the tap run wide open the water gets down to 67 F.

Andy

 

[Buckeye Hydro]

<a href=showthread.php?s=&postid=10195639#post10195639 target=_blank>Originally posted</a> by apw63
Thanks for the info!

I tested my cold water temp, and straight out of the tap it is 72 F. My RO/DI system only produces around 4 gph. I think at that rate of production the water temp should stay around 70 F. If I let the tap run wide open the water gets down to 67 F.

Andy

Andy - relative to others who use RO in this hobby, you summertime tap water temperature is not unusual. The real kicker is winter tap water temperatures. That's when we hear most complaints about low production of pure water.

We have a calculator on this page ( http://buckeyefieldsupply.com/calc.asp ) that allows you to plug in various pressures and temperatures and see the effect on production from an RO membrane.

Russ