I'm trying to automatically adjust my window size based on a global

parameter called "Glazing Percentage". The width of the window is fixed

and the height is defined by the following expression:

4.47*(#PA("Glazing Percentage")/0.4)

However, a large glazing percentage leads to problems since the larger

window takes up space in the plenum. So I want to fix this by adjusting

the Y coordinate of the window. To do this, I tried creating the

following expression:

if (#PA("Glazing Percentage") == 0.4)

then #L("Y") = 4.37

else #L("Y") = 4.37 - (1.12*("#PA("Glazing Percentage) - 0.4))

endif

When glazing percentage is set to 0.4, the above expression sets Y to

0.00. As soon as I change it to says 0.5, eQuest crashes.

The math is correct, but there's something wrong with my syntax. Can

anyone please help?

I've attached the pd2 and inp files for reference.

Thanks,

Luka

Sorry, I fixed the typo in the expression. It should say:

if (#PA("Glazing Percentage") == 0.4)

then #L("Y") = 4.37

else #L("Y") = 4.37 - 1.12*(#PA("Glazing Percentage") - 0.4)

endif

And no, that didn't fix it.

Ok I found my mistake.

It's unnecessary to use "#L("Y") " to define the value of Y. I think I

ended up getting into a circular reference problem.

The correct expressions is:

if (#PA("Glazing Percentage") == 0.4)

then 4.37

else 4.37 - 1.12*(#PA("Glazing Percentage") - 0.4)

endif

For those that are on both the BLDG-SIM and this list, I apologize for

the repost...

Question on PIU vs. VAV systems in eQuest...

If a PIU system has only SVAV boxes and all other parameters are

identical, does the PIU act like a VAV in eQuest? Only changing the

system type in my model seems to have a significant impact on energy

usage and I can't track down why that is. The difference is significant

enough that with App. G System 7 VAV w/RH, the choice between PIU and

VAV has an effect on the number of points. Any thoughts would be

appreciated.

Thanks,

Matt

Matt -

You may be observing the result of the different default for

"THERMOSTAT-TYPE" for zones served by each system. The default for VAVS

is "REVERSE-ACTION" while it is "PROPORTIONAL" for PIU. Take a look in

the DOE-2 documentation for descriptions of each of these and how this

property affects ZONE terminal unit and SYSTEM operation.

Kevin Madison