Re: [TRNSYS-users] Type22 - controlling floor-heating/cooling

[David BRADLEY <d.bradley@tess-inc.com>]

Daniel,
  Often when writing controller models, I add an input or a parameter to tell the controller whether it is operating in heating mode (ie ON when a temperature is too low) or in cooling mode (ON when the temperature is too high). Type22 does not have such a mode so you might need to use two of them, one looking at the temperature difference for heating times and one looking at an inverted temperature difference for cooling.
Kind regards,
 David


On 4/15/2011 09:03, Daniel Bader wrote:

Dear TRNSYS-Users,

 

I have a little problem to control my floor-heating- and cooling-system:

 

I use Type22 – Iterative feedback controller – to regulate the massflowrate of the floor-system.

The inlet temperature is controlled by the mean outside temperature of the day before.

 

In times when the floor is used for cooling the building, the Type22-controller works perfectly.

But in times when heating is needed, the controller doesn’t use the threshold-function to stop the massflow if the rooms are getting too hot (because of internal gains).

 

Think for example at a room in winter with outside temperature about 0°C.

In the night and in the early hours there will be a heating demand, so an inlet-temperature of about 22°C is used for heating.

When the room is used (with lots of internal gains) the inlet temperature of 22°C is used for cooling!

The problem is that you cannot control both (heating and cooling).

Also by adding an on/off command to type22 (like: off when Tair > Twanted – I tried a lot more) doesn’t work.

See also the attached graph (I hope you can understand the problem).

 

Does someone have experiences with that problem to  solve this problem?

 

I would be very pleased for any help!

Thank you in advanced.

 

Kind regards / Freundliche Grüße

 

i.A. Dipl.-Ing.(FH) Daniel Bader

 

GN Bauphysik Ingenieurgesellschaft mbH

Bahnhofstr. 27

70372 Stuttgart

Tel.: 0711-9548800

Fax: 0711-564613

www.gn-bauphysik.com

Geschäftsführer: Dipl.-Ing. (FH) Manfred Finkenberger

Sitz der Gesellschaft: Stuttgart, HRB 14870

 

 

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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

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d.bradley@tess-inc.com

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