Need logic help to calculate the Enthalpy on the basis of given standard table.

[lalitkgehlot89]

Hi,

I want to calculate the water Enthalpy on the basis of given Pressure and Temperature.

There is standard table given on the basis of that i want to calculate the Enthaply. Standard table and input data file in attachment.

Logic is also given in Standard table file.

[ogautier62 · Accepted solution]

Hi

attachement is missing !

[lalitkgehlot89]

Hi get the attached file.

[ogautier62]

thank's

not quite simple ! need some reflexion

[ruma_barman]

stalwar1‌

[sunny_talwar]

Hi Ruma -

I am not sure I follow the logic of what you are trying to do? Do you mind elaborating a little bit as to what is going on within Standard Table?

[ogautier62]

Hi Lalit,

- first load inline manually a reference table like this :

RefTable

T11      T12     P1      E11    E21     P2       T21   T22   E12       E22  

100    150     0,01    2687,5   2783   0,05   100   150    2682,4    2780,2

150    200     0,01    xxx        xxxx   0,05   150   200    xxxx     xxxxx

Eij = enthalpy for Pi Tj

then load your 'input data'  outer join with refTable

where pressure < = P1    <P2   and temperature <=T11  < T12    and <= T21   < T22

  pressure         temperature      T11   T12  P1  ...........

0,1                      100                100   150   0,01 ............

0,1                     270                250   300     0,01   .............

- then you calculate EP1 et EP2 for your temperature as logic 3 :

EP1 :

E11 + (temp - T11)/(T12 - T11) *(E21-E11)

idem EP2 for for P2 and your temperature

- then you calculate E as

linear approx beetween EP1 and EP2

regards

[lalitkgehlot89]

Hi Sunny,

In Scenario I have Pressure and Temperature as source data to calculate water Enthalpy at that pressure and Temperature . on other side I have a standard Table which provides me fixed Enthalpy value at fixed Pressure and Temperature.

For Example :-   Pressure   0.01      Temperature  50.00        Enthalpy   2592.00

                           Pressure   0.01      Temperature  100.00      Enthalpy   2687.50

on the basis of these Pressure and Temperature, Need to calculate water Enthalpy @ Pressure 0.01 and Temperature 75.00.

Enthalpy value at 75.00 temperature not exists in table. it comes between 50 and 100.

Logic for Enthalpy Calculation =  (Enathalpy value at 0.01 Pressure and 50.00 Temp. )  + (( Calculation Temp - upper temp)/(lower temp  - Upper temp))* (lower Enthalpy value - upper Enthalpy Value)

=>   (2592.00)  +(( 75.00 - 50.00)/(100.00 -50.00)) * ( 2687.50 - 2592.00)

As per data I have three situation,

1) Pressure  matched with standard table data but Temperature comes in between two temperature.

2) Temperature matched with standard table data but Pressure comes in between two Pressure.

3) Both Temperature and Pressure  comes in between two Temperature and Pressure.

Logic for all is on Input data sheet of attached file.

standard Table id on Convert Table sheet of attached file.

[lalitkgehlot89]

Hi Olivier,

As Per actual data its not a small table. Please get the actual table attached file.

Sheet "Convert Table" is actual table. and Sheet "Input data" has source Temperature and Pressure against that Enthalpy is required.

Please help me out to write the logic. 

[ogautier62]

lalit,

if you have only 9 input data, why use Qlikview ?

make some C/java program to calculate interpolated enthalpy