[esp-r] Re: Mixing plant and ideal zone controls

[Marco Manzan]

> Date: Mon, 26 Oct 2009 23:15:28 +0100
> From: "Christian Anker Hviid" <cah at byg.dtu.dk>
> Subject: [esp-r]  Mixing plant and ideal zone controls
> To: <esp-r at lists.strath.ac.uk>
> Message-ID: <78B14BBA2B77DF4186B975430E16648B0D1053 at mail3.byg.dtu.dk>
> Content-Type: text/plain;	charset="iso-8859-1"
>
> A question about plant and ideal zone control that I hope someone  
> has a solution for.
>
> I have one zone ventilated by a plant with and without heat  
> recovery. I think I need to link the plant to the zone before the  
> effect of the heat recovery shows in the energy delivered.
> But I also need to specify a zone control that keeps the zone  
> temperature at 20degC. I know I can put in a heating coil into the  
> plant and control it to approximately 20degC, but for the sake of  
> simplicity (in larger scale models) I just want to control my room  
> temperature ideally. How do I link a plant and an ideal zone control  
> to the same zone?
> I think the same problem arises if I want to link an air based and a  
> water based plant to the same zone?
>
>
>
>
>
>
>
> Best regards
>
> Christian Anker Hviid
> Industrial PhD candidate
>
> DTU Byg
> Technical University of Denmark
> Brovej, building 118
> DK-2800 Lyngby
> Phone DTU: +45 4525 1886
> Phone Alectia: +45 8819 1365
> Mail: cah at byg.dtu.dk
>

If only energy balance is concerned you can simply avoid the plant by  
using heat recovery efficiency and changing accordingly the air change  
rate into the zone. If you have a 1 ach external air into the zone and  
heat recovery efficiency is 90 % you can change the infiltration to  
0.1 ach, this way you can still use an ideal zone controller. This  
schema does not works if you want to control also humidity, because  
also external moisture is affected by the reduced infiltration. In  
this case you have to simulate the plant avoiding the ideal controller.

best regards

Marco

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|Marco Manzan               Email: manzan at units.it            |
|Tel:   (+39) 040 5583506   Fax  : (+39) 040  572033          |
|Dipartimento di Ingegneria Navale, del Mare e per l'Ambiente |
|Universita' degli Studi di Trieste                           |
|piazzale Europa 1, 34127 TRIESTE                             |
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