Dear TRNSYS folk,
I was wondering if anyone can shed some
light on Type60, in particular low flow operation of the
immersed heat exchanger model (IHX). I’m using the 16.01.0003
edition of TRNSYS and 2005-01-31 – Mku version of Type60.
I’ve been happily simulating high-flows
(>40kg/hr per m^2 collector area) but run into
non-convergence warnings (and infinite loops) with, for
example, a specific collector flow of 10kg/hr; storage volume
400 litres with 25 nodes and a simulation time step between 3
and 6 mins; http://sel.me.wisc.edu/trnsys/mailinglist/archive2004/msg00640.html.
I have tried reducing the flow rate to a minute and even less
but non-convergence persists (for an annual simulation that
doesn’t abort I get between 2 and 5 thousand warnings). Some
exemplary energy balances (measured with Type60) are as
follows;
10kg/hr:
Q_coll + Q_aux = 13934081.86 kJ
Q_losses + Q_dhw = 13920759.15 kJ
Q_coll + Q_aux – Q_losses – Q_dhw = Q_err =
13322.71 kJ
50kg/hr:
Q_coll + Q_aux = 13961476.57 kJ
Q_losses + Q_dhw = 13947209.16 kJ
Q_coll + Q_aux – Q_losses – Q_dhw = Q_err =
14267.41 kJ
Is this all within reason? If not, any
tips?
Kind regards,
William Logie
Forschung / Research
Institut für Solartechnik SPF: Adresse / Website
Hochschule für Technik Rapperswil HSR
Tel. +41 55 222 48 34
Fax +41 55 222 48 44