Problem in modelling

[daraeikh]

Hi everyone,

I am trying to model a gas station which has a delivery once a year (e.g. 20ML/year) and
consumption within the year (e.g 15ML/year). Since my delivery is discrete ( it only
occurs once a year), how I can mode it properly?
If I use "Pulse function", with time step equal to 0.25, at the end of the year, the
model consider delivery equal to 0.25*20=5ML, while in fact 20Ml has been delivered.

Many thanks in advance for your help.

[Administrator]

If the time step for your model is in days, the following should work. Use the "ORDER NOW FLAG" to trigger the order.

Tony.


TIME BETWEEN ORDERS = 30
Units : Day

ORDER NOW FLAG = IF THEN ELSE ( Time Since Last Order
>= TIME BETWEEN ORDERS
, 1
, 0 )
Units : DMNL

RESET TIME SINCE LAST ORDER = order now flag
* Time Since Last Order
/ TIME STEP
Units : day/day

TIME SINCE LAST ORDER = INTEG ( TIME STEP / TIME STEP - reset time since last order , 0 )
Units : day