AW: [TRNSYS-users] Controlling of the main solar circle pump and of the starting circle pump

["Timo Sengewald" <timo.sengewald@bls-energieplan.de>]

Flo,

your construction seems pretty complicated to me. Why don't you install
just one pump for the collector circle (primary circle for the heat
exchanger, no bypass) and another pump for the storage circle (secondary
circle for the heat exchanger)? You can start the collector pump when
the collector outlet temperature or the insolation reach a certain value
and then start the secondary pump when the temperature difference
between heat exchanger inlet temperature (primary) and storage tank
temperature reach another specified value. This is how I got to know the
control design when using a heat exchanger and storage tank.

When you like to avoid a flow rate over the heat exchanger while the
secondary pump is turned off (but ideally there is no heat loss when one
flow rate is 0) I would suggest using one pump for the collector circle
and a three way valve to control the mass flow through the bypass
(controlled by a differential controller).

Timo



________________________________________________
Timo Sengewald

BLS Energieplan GmbH
Elsenstraße 106
D-12435 Berlin
Tel.: +49 30 53 32 81-0
Fax: +49 30 53 32 81-40


www.bls-energieplan.de


-----Ursprüngliche Nachricht-----
Von: trnsys-users-admin@engr.wisc.edu
[mailto:trnsys-users-admin@engr.wisc.edu] Im Auftrag von hafner
Gesendet: Dienstag, 26. Oktober 2004 14:18
An: Trnsys Users
Betreff: [TRNSYS-users] Controlling of the main solar circle pump and of
the starting circle pump


Dear users,

many solar collector systems have two pumps . the main  solar circle 
pump, which causes an flow rate over the heat exchanger and the starting

circle pump ,
which causes an flow rate over an bypass pipe . So the starting pumps 
starts , if the temperture difference(1) is big enough. if the 
temperature in the bypass pipe is
nearly the collector out temperature (controlling temperature difference

2) , the solar circle pumps starts, and the starting pump should stop. 
So if the temperture difference (1) is lower x ,than the solar pump 
should stop.
So the controling difference is the start condition for the first 
pump,and the stop condition for the second pump.
What is your solution for this ,and does it make sence to simulate this.
Thanks Flo


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