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# Incoming heaters for RO membranes

## Incoming heaters for RO membranes

(OP)
Hello all...I'm trying to size parallel instantaneous domestic hot water heaters (twin 10kW units from Grainger) serving a process reverse osmosis skid. BUT the flow through the RO membranes is governed by incoming temperature. So starting with raw city water at 45F, the initial dT will be high, then decrease as the RO membranes allow more flow. as flow increases, the dT across the heaters will drop. Any tips on determining where it'll balance out? I'm thinking graphing an iteration by the minute in Excel starting with 45F. I have the flow vs. temperature data from the RO manufacturer as known. Any help is appreciated.

### RE: Incoming heaters for RO membranes

Iteration is how you do it.
You could narrow it down by platting the flow vs temp for both units on the same graph.
Where they cross will be in the ballpark.

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P.E. Metallurgy, consulting work welcomed

### RE: Incoming heaters for RO membranes

(OP)
Thanks. I will try that.

### RE: Incoming heaters for RO membranes

(OP)
Looks like it worked. Thanks!

### RE: Incoming heaters for RO membranes

It will be interesting to see how close that is to the actual.

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P.E. Metallurgy, consulting work welcomed

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