+Mitch Posted January 15, 2014 Share Posted January 15, 2014 I'm too lazy to do my own interweb research, and figure I can leverage the group's shared knowledge Given the typical Texas weather we live in with the temps fluctuating from the 20's to the 70's, how does temperature affect the efficiency of RO/DI systems? I believe the only other factor affecting efficiency is water pressure. What's the ideal? How low of a pressure necessitates the use of a booster pump? How much is too much pressure? How do either affect the rate at which DI resin is consummed? The filters? TIA Quote Link to comment Share on other sites More sharing options...
victoly Posted January 15, 2014 Share Posted January 15, 2014 If you mean effeciency in terms of time, i *think* that colder water would reduce the pore size of the RO membrane and reduce your output rate in addition to reducing the pure/waste ratio. I don't think it should affect resin consumption, because the water coming out of the RO should be of the same quality, it just gets there slower. As for pressure, i believe that higher pressure is better (i.e., it pushes water through the membrane faster), but that you get a diminishing return after what you would expect your max household water pressure to be (something like 80 psi is where the charts start to drop off). You have other things that will fail on your unit (fittings) before you can go too terribly high, and you don't gain anything from doing so. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted January 15, 2014 Author Share Posted January 15, 2014 On BRS's booster pump description, they list as a benefit of higher pressure: Reduced DI resin consumption Quote Link to comment Share on other sites More sharing options...
victoly Posted January 15, 2014 Share Posted January 15, 2014 huh, really. I wonder what the reduction in consumption is. Now if your pressure is super low and you use a booster to get it to where it needs to be i can reason that out. But if your pressure is in normal range and you go higher than that, i can't work out how that would reduce consumption. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted January 15, 2014 Author Share Posted January 15, 2014 So what's the ideal range for temp and pressure for best performance of an RO/DI system? Quote Link to comment Share on other sites More sharing options...
victoly Posted January 15, 2014 Share Posted January 15, 2014 The membranes GPD rating is measured at 65 psi and 25 C (77, f) so i would assume that it is in that neighborhood. 2 Quote Link to comment Share on other sites More sharing options...
Planeden Posted January 15, 2014 Share Posted January 15, 2014 huh, really. I wonder what the reduction in consumption is. Now if your pressure is super low and you use a booster to get it to where it needs to be i can reason that out. But if your pressure is in normal range and you go higher than that, i can't work out how that would reduce consumption. seems that the reasoning would be the same regardless of low vs. super low? does DI resin dissolve? if so, lower pressure = extra contact time = extra consumption. i wonder how much of it is marketing the pumps. @65 psi you get 500 gallons. at 30 psi you get 499.99 gallons. ergo, bump your pump and get longer life...just not noticeably longer. (note values just made up for illustrative purposes. could be off by orders of magnitude) Quote Link to comment Share on other sites More sharing options...
jestep Posted January 15, 2014 Share Posted January 15, 2014 Isn't the waste water difference pretty significant when using a pump. Most of the boosted systems I've looked at have 1:1 pr 1:2 RO to wastewater. Most of the decent quality BRS or Spectrapure and others without a pump are 1:3 - 1:6. If that's all it takes to save 75% of the water that would otherwise be wasted it definitely looks worth it. DI resit swaps molecules so more contact time would equal quicker exhaustion. I can see temp affecting them but can't really see how pressure would have a negative effect on exhaustion rate. Quote Link to comment Share on other sites More sharing options...
victoly Posted January 15, 2014 Share Posted January 15, 2014 huh, really. I wonder what the reduction in consumption is. Now if your pressure is super low and you use a booster to get it to where it needs to be i can reason that out. But if your pressure is in normal range and you go higher than that, i can't work out how that would reduce consumption. seems that the reasoning would be the same regardless of low vs. super low? does DI resin dissolve? if so, lower pressure = extra contact time = extra consumption. i wonder how much of it is marketing the pumps. @65 psi you get 500 gallons. at 30 psi you get 499.99 gallons. ergo, bump your pump and get longer life...just not noticeably longer. (note values just made up for illustrative purposes. could be off by orders of magnitude) I think that the intended purpose of a booster pump is to get a low pressure system to a normal range system, and not from normal to high pressure. I think you're totally right about the marketing proposition there. Isn't the waste water difference pretty significant when using a pump. Most of the boosted systems I've looked at have 1:1 pr 1:2 RO to wastewater. Most of the decent quality BRS or Spectrapure and others without a pump are 1:3 - 1:6. If that's all it takes to save 75% of the water that would otherwise be wasted it definitely looks worth it. DI resit swaps molecules so more contact time would equal quicker exhaustion. I can see temp affecting them but can't really see how pressure would have a negative effect on exhaustion rate. I remember reading somewhere that those systems incorporate additional processes to keep the membrane flushed, and to automatically dump the first few gallons of RO prior to it hitting the resin. I think it was in PMRogers build thread. Either way, i think there's more to it than keeping the system running at high pressure. Quote Link to comment Share on other sites More sharing options...
+Mitch Posted January 16, 2014 Author Share Posted January 16, 2014 This is the response I got from BRS when I queried them: "We recommend 77 Degrees and 65 psi. Although being a little off from these will not harm anything. These are just optimal specs." Quote Link to comment Share on other sites More sharing options...
+Mitch Posted January 16, 2014 Author Share Posted January 16, 2014 Also, BRS customer service guy said he wouldn't personally run it below 40 psi. Quote Link to comment Share on other sites More sharing options...
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