Re: Question about type 1 (Solar Collector)

["David Bradley" <bradley@xxxxxxxxxxxxxxx>]

Dear Maurice,
	I suspect that there may be a problem with the setup of Type 1 in your
system because TRNSYS does not assume that the inlet temperature of the
flow through the cold side of the heat exchanger and the inlet temperature
of the flow through the collector are equal unless the heat exchanger is
set up with an efficiency of 100%. The cold side of the heat exchanger is
the tank side so whatever temperature fluid is found at the bottom of the
tank, will be the inlet temperature on the cold side. The inlet temperature
to the collector is the outlet temperature of the heat exchanger "hot" side. 
	If you could send me the .dck file that you are having trouble with, I
would be pleased to take a look at it (bradley@sel.me.wisc.edu).
Alternatively, you might consider using the Type 5 heat exchanger instead
of the one that is built into Type 1.
Cheers,
	David 

At 02:40 PM 1/3/01 +0100, you wrote:
>Dear TRNSYS users,
>
>Now I am busy with a simulation of a system with a solar collector, a heat
>exchanger an a storage tank for a hot water system for a house. For the heat
>exchanger I use the integrated heat exchanger in type 1 (Solar Collector).
>The tenth parameter of type 1 indicates the effeciency of the heat
>exchanger.
>
>The necessary inputs are among other things the solar radiation, the flows
>through the collector and the heat exchanger and the inlet temperature of
>the fluid of the cold side of the heat exchanger. The outputs of type 1 are
>the the outlet temperature of the flow of the cold side of the heat
>exchanger, the flow trough the collector, the rate of energy gain and the
>outlettemperature of the flow through the collector.
>
>I think that the inlet temperature of the flow trough the collector depends
>on the efficiency of the heat exchanger. The worse the efficiency of the
>heat exchanger, the less the temperarure difference between the inlet and
>outlet of the flow through the heat exchanger. I remarked that you cannot
>find this effect in TRNSYS. Type 1 (Solar Collector) supposes that the inlet
>temperature of the flow through the cold side of the heat exchanger and the
>inlet temperature of the flow through the collector are equal. I think this
>is not correct. Does anybody has an idea to avoid this problem ?
>
>I also remarked another strange thing in type 1 (Solar Collector). When I
>use the quadratic efficiency mode (parameter 1 is 1) and the first order
>coefficient of the efficiency curve is 0, then the collector outlet
>temperature and the outlet temperature of the cold side of the heat
>exchanger are equal. This is independent of the efficiency of the heat
>exchanger. I think this is not possible. Does anybody has an explanation
>herefor ?  
>
>With kind regards,
>
>
>Maurice Jong 
>
>=====================================================================
>
>Maurice Jong
>ECN - Energy Research Foundation      Department: Zon, Group DEGO
>P.O. box 1    1755 ZG  Petten              Country:   The Netherlands
>Telephone:    (+31) 224 564938             Fax:       (+31) 224 568966
>E-mail: jong@ecn.nl                             Internet:
>http://home.soneraplaza.nl/mw/prive/mjmjong/
>
>=====================================================================
> 
---------------------------------------------------------------
David BRADLEY
1500 Engineering Drive		ph: +1 608 263 1589
Madison, WI				fax: +1 608 262 8464
53706 
URL: http://sel.me.wisc.edu/trnsys
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