Plate Heat Exchanger Output

[Johntheo5]

Someone familiar with PHE calculations (SimonH2??) might have a look at this and comment/correct.

Someone asked me to have a look at the output from a Nordic BA 23-40 165kw PHE, all their PHEs have a heat transfer coefficient of 6200W/M2 deg C. the known inputs are primary flow 33.76LPM at 53C, required secondary temperature 48C from cold water at 5C, my calculations below show that the 0.92M2 Hx should give a output of 63.59kw with a secondary flowrate of 21.2LPM. Nordic technical inform me that a 1.98M2 Hx is required (closest Hx is their 2.24M2) to give these outputs/flowrates, am awaiting a reply as to why this is.

 

[Johntheo5]

I also asked Nordic what performance they expected from the above and they replied.......

Side 1) - 33.76 l/min, inlet temp. 53oC

Side 2) - 12 l/min, from 5 to 48oC
Then 35 kW

The only way I can "achieve" this is by reducing side 1 flowrate to 12.37LPM (from 33.76) or reducing the heat transfer coefficient to 2570 (from 6200).,

 

[Johntheo5]

Reply from Nordic, below.

LedNet​	7:17 AM (33 minutes ago)
to me

Hello
We use the sizing software and we rely only on it - we are not reffering so deeply to the manual calculations by our potential Customers. We rely on ours only. Sometimes we got the similar request to study somebody's project and calculations, but we don't reffer to this (as a rule), because we got more than 150 sizings per day, even out of the hot season.
I checked this once again, what my colleage did before - and it looks correct. You can rely on this.
Side 1) - 33.76 l/min, inlet temp. 53oC
Side 2) - 12 l/min, from 5 to 48oC
Then 35 kW