[esp-r] Re: radiator modelling

[Jon Hand]

An abstract representation of a radiator would be to use an ideal zone control
which has a mixed sensor and a mixed actuator (radiant & convective).  One of
the models included in the source (src/validation/DSM/stone_simi_1890) uses
this kind of representation for a WCH system.  It certainly provides the rough
kind of control one gets with TRV (which are strongly influenced by the
radiant environment in the room) and radiators in rooms (most conventional
radiators mostly act as convectors).

The thin zone approach could be done - the side next to the wall would be
(from the outside to the inside)  wall stuff, air gap, metal.
The side facing the room would be just metal.  Set high hc inside the
thin zone.  Be careful about the control.  You are actuating in one zone
but sensing conditions in another zone.  The combination is a bit of a
mind-twister.

-Jon Hand
________________________________________
From: esp-r-bounces at lists.strath.ac.uk [esp-r-bounces at lists.strath.ac.uk] On Behalf Of Andrew Cowie [cn06arc at leeds.ac.uk]
Sent: 19 December 2012 15:13
To: esp-r at lists.strath.ac.uk
Subject: [esp-r]  radiator modelling

Hi all,

I'm trying to model a bog standard radiator in a one-room model.  At the moment im using the thin-zone approach as detailed in exemplar rad_rooms_heat, however it has occurred to me that when a panel is inserted into a surface to link with the thin-zone, it replaces as opposed to augments the construction of the wall that it is on, as obviously it needs to be only a very thin conductive construction for the model to work.  I have found that this actually has a noticable effect when the radiant panel is on the external face of the room.

So my question is this: is there a more explicit way to model a radiator in ESP-r without building a plant network? (i don't really want to use a plant network as a. it seems rather like overkill to create a whole network simply for one element and b. it only introduces more assumptions and complexity into my model)  Basically all that is required is a radiant panel (retaining the construction of the wall behind it) that is maintained at a constant supply temperature; i am not particularly fussed about control laws.  If it is possible to also model heat transfer with the wall behind it this would be ideal, though i appreciate that this would necessitate changing the heat transfer in the fabric from 1-D to 3-D.

Thanks,
Andy Cowie
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