return 'no value' in conditional statement

Question

I am using a conditional statement to calculate the U-value of heat exchanger. If conditions are not met, I would like to return a nan rather than 0. How can I do this?

if(

and((Q_warm < 13), (Q_warm > 11)),

(Q/(3.64*LMTD)),

0)

Wouter Daniels · Answer

There is no direct nan available, but you can take the square root of a negative number to the same effect. The resulting formula tag will be interpolated over the period with nan values.

if(
    and((Q_warm < 13), (Q_warm > 11)),
    (Q/(3.64*LMTD)),
    sqrt(-1)
)

If you want to see actual gaps, a workaround would be to return 'infinite' values, though any calculations/aggregations done on the tag will also show the value to be infinite for those periods.

if(
    and((Q_warm < 13), (Q_warm > 11)),
    (Q/(3.64*LMTD)),
    1e99
)

return 'no value' in conditional statement

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