Heat Exchanger Flow

Are you trying to heat the cold water, or cool the hot water?

I would be very helpful (dam near necessity) to know the surface area and liquid volume of each plate in order to arrive at any meaningful number.

So, you're on your own.

Did you check the manufacturer?

Why pump water at all? From the sparse information you provided you could just pour 52° C water into a bucket made of 50 3mm thick diamond plates that has a thermometer immersed in the water. The plates are not diamond plate steel. They're diamond with a thermal conductivity of 22W/[cm*K]. When the water cools to 47° C from evaporation and heating the air, pour your cooled water out. I know that this is not what you wish to do but it does meet your criteria.

To make this absurd answer I had to make several assumptions. I will not waste my time playing 20 questions finding out what is the real situation.

36gpm......

Of course it could be different according to the actual design you are addressing....

http://www.ewp.rpi.edu/hartford/~ernesto/F2011/EP/MaterialsforStudents/Libardi/Shah2003-Ch9.PDF

Yes, see #3

Sorry, but I wrote the answer as soon as I read the question without a look at all other comments. In fact I read the first and did not go further.

I give you a GA!

No problem but thanks anyway!

I have a principle: if you want to be respected you should give respect to the other!

It depends on the size (especially surface area) of the heat exchanger.

Nope, it depends on joules in versus joules out and joules dumped. Since we know none of these i choose 42.

At least I didn't say only on the size. K too....

Your answer is correct.

However, as Good Name points out in his reply #7, your analysis can confirm that, while we DON'T know the HEAT FLOW, we DO know the ratio of the WATER FLOW rates:

W cold / W hot = ΔT hot / ΔT cold = ( 52 - 47 ) / ( 32 - 28 ) = 1.25

Dear Mr.Zvi,

The Original Post reads as "I want to know the water flow capacity required............"

THE CAPACITY REQUIRED (obviously cold water) is the NEED or to be Known, by the Original Poster. Based on that I have pointed out that I ave given details and concluded that 2 unknowns in an equation cannot be solved, which you also know.

As Mr. Code Master has suggested in his posting No.3, above, you have derived the Ratio, which in my opinion, WILL NOT SATISFY the Quiery by the Original Poster.

DHAYANANDHAN.S

Yes, see #3

"water flow capacity" should be plural "capacities" and since you are dealing with rate of flow and volume for two separate system flows to achieve the temperature changes, you need a "Flowrater" on each water line. Then you know the rate of flow and the input temp and output temp for the warm water you will know the required capacity for that system. Then the same applies to the cold water system. Then you will be able to calculate and adjust for the variations in temperatures between the two systems to maintain the desired result. Get some Flowraters for a closed system or graduated barrels at the drains and a stopwatch.