[esp-r] Re: CFC control and U-value.

[Geissler Achim]

Dear Hugo

did you try defining different start times (more than one control period) for your "night time" issue? That should be possible.

On your second issue, yes, the CFC deals with U-value calculation internally, but to check "what you have" the simplest approach is to use Window, as you write. The thickness of the glass and the width of the cavities are taken from the mlc construction, however, so these must be correct in terms of "they must be according to the build-up of the glass you are looking at". The U-value is not a constant with CFCs.

The "QA report" contents is wrong for CFC constructions. This report uses the entry from the mlc construction. The U-value reported thus uses the gap resistance entered in the mlc.

Regards
Achim


Von: esp-r-bounces at lists.strath.ac.uk [mailto:esp-r-bounces at lists.strath.ac.uk] Im Auftrag von Hugo Santos
Gesendet: Mittwoch, 20. Juli 2011 18:43
An: ESP-r mailing list
Betreff: [esp-r] CFC control and U-value.

Good afternoon to everyone,

My question is mostly directed to Bartosz Lomanowski but maybe somebody else may have the answers.

I've successfully implemented CFC windows in my models but there are two details that are bugging me:

The first one is related to the complex fenestration control (by schedule) and more specifically the simplest on/off control. In it there are two setpoints to be defined for opening and closing the shading layer. I'm assuming that, when using a temperature sensor, the closing setpoint works in a direct way (shading is closed when temperature goes OVER the setpoint) and that the opening setpoint works in a inverse way (shading is opened when temperature goes BELOW the setpoint). If that is the case, then how may I implement a control that opens the shades at night when the internal temperature is over a specific setpoint (which seems contrary to the control logic)?

The second issue is how can I be sure of the U-value for my glazing system? Is conduction dealt within the CFC model or should my MLC emulate the correct U-value for the glazing system? Looking at the .cfc files, it seems that conductivity for glass is not taken into account, only the gas layers have conductivity values attributed to them while glass layers seem to only have optical characteristics. If CFC takes glass conductivity into account, does that mean that to find the U-value I must recreate the glazing system defined in GSLEdit but in a program like Window 6 in order to find exactly what are the physical characteristics of the glazing system?

Thanks in advance for any help. Regards,

Hugo Santos
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