How To Calculate Plate Type Heat Exchanger

How To Calculate Plate Type Heat Exchanger

   The plate heat exchanger is a new type of high-efficiency heat exchanger formed by stacking a series of metal plates with a certain corrugated shape. A thin rectangular channel is formed between the various plates to exchange heat through the plate. Compared with the conventional shell-and-tube heat exchanger, the heat transfer coefficient is much higher under the same flow resistance and pump power consumption, and there is a tendency to replace the shell-and-tube heat exchanger within the applicable range.

Application

Hot side- 65M3/H, Inlet :90 ℃,Outlet:45℃,Cold side-58.5M3/H Inlet:25℃,Outlet:75℃,Pressure:100Kpa

 physical parameters

Hot fluid: Density(ρ1)=979.1kg/m3   Specific heat(cp1)=4.185KJ(kg. ℃)

Cold fluid: Density(ρ1)=988.1kg/m3   Specific heat(cp1)=4.174KJ(kg. ℃)

Design process

1. Heat load (Q)=qm1 .cp1(t1’- t1”)=(65/3600)x979.1x4.185x(90-45)=3329.25Kw

2. Logarithmic mean temperature difference
Tm=T1-T2÷㏑(T1/T2)=(20-15) ÷(20/15)=17.38℃

3.The K-Value(heat transfer coefficient)
water and water:2000-7000w/m
2
water and oil:150-900w/m
2℃ 
Steam and water:1000-2000w/m
2℃ 
water and milk:1000-4000w/m
2

4.Heat transfer area A        Q=AK Tm         A=Q/ Tm.K=3329250W/17.38.4100=46.72

5.Confirm the model and the gasket

Following the flow rate ,we check it require the DN100 connection, Then our model is BR10MBL, The heat transfer area is 0.3.so the model is :  TL10M-10-157-E, with 157 pcs plate
The gasket is according to the temperature and the fluid
NBR  design temperature 110 ℃
EPDM design temperature 150 ℃


6.Check  the velocity in the connection and the two plate
Connection velocity W1 ≤ 3.5-4.5m/s
 Velocity between two plate=Flow rate/Pass x(corrugation depth-plate thickness)x plate width=0.1-0.4m/s
Then for this application W1=4q/3600. π D
2=4x65/(3600x3.14x0.12)=2.26m/s , it ok for this connection
Velocity between two plate=(65÷3600)/(39x0.0034x0.369)=0.37m/s, this is good.
So confirm the model is: TL10M-10-157-E
Pass: 2x39/2x39


Plate heat exchanger pressure drop

About the pressure, General, the customer  advice less than 150Kpa. The pressure according the  Velocity between two plate, if the velocity is quickly , the heat transfer coefficient is high, the pressure will so big. The designer will following the pressure drop requirement to adjust the heat transfer area.