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

[Hugo Santos]

Dear Achim,

Thanks for the help on the U-values.

As for the CFC control issue, I already established three periods per day to
account for the day and night periods. The problem is upon defining the
control law. I wanted it to be: during the day, turn the shading ON if
internal temperature is over 23°C and OFF if below 22°C; but during the
night period I wanted it to turn OFF if internal temperature is over 23°C
and ON if below 22°C. That is, the inverse! I can't quite understand how the
setpoints for the on/off law are executed or how this could be implemented
with them. There is, for instance, no way of saying if the CFC setpoints
work in a direct or inverse way as in the multi-sensor law for network flow
control.

Thanks again. Cheers,

Hugo Santos


On 21 July 2011 10:45, Geissler Achim <achim.geissler at fhnw.ch> wrote:

> 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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