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Re: [TRNSYS-users] Question about Type 563 hybrid solar panel



Dear David,

 

Thanks for the answer. I looked into the Fortran file, but i don’t know how to recompile the DLL file.

 

I had another question yeah I want to understand the total model sorry for the many questions. I was looking to usefull gain and it is a bit strange because it looks like you need a minimum PV power to get some energy gain. Because below 990 kj/hr there is no usefull gain and then suddenly above this 990 kj/hr you have 4560 kj/hr. My panel is 4 by 5 but how can you explain this. Another thing in the summer there is no direct sunlight on the panels because it are facades and the sun in Hong Kong is high in the summer. According to the model there is then also no PV power, but there is still diffuse radiance on the panel and this will heat the panel also up so why no PV Power.

 

The last question how is the controller(type 2b) working? I monitored the controller and the pump and the temperatures which go in the controller but until now I cannot find a relation. In the controller and the pump I didn’t change anything compared to the basic model. The pump is type 3b and the controller type 2b. I also already looked in the documentation and I found there you have to look to the difference between the upper and lower limit so I do and compare this with your dead band limits I also did that and what I don’t understand is how this dead band works. I did already multiple tests with no dead band(I understand) but as soon as I try a low or high dead band I cannot find logic in it. I really want to understand it.

 

For example the low dead band is 2 and the higher dead band is 10 like the default settings

Then you expect when the difference is getting higher than 10  the control signal should go on but it happens already before it reaches 10 and it would  go off when it drops below the 2 but it sometimes already goes off above 2 and that makes no sense to me. Or has this to do with the number of oscillations.   

 

I hope to hear from you soon. Thanks in advance.

 

Best regards,

 

Benjamin Stobbe

 

Van: David BRADLEY [mailto:d.bradley@tess-inc.com]
Verzonden: vrijdag 21 augustus 2015 1:29
Aan: TRNSYS users mailing list at OneBuilding.org <trnsys-users@lists.onebuilding.org>; benjamin_stobbe@hotmail.com >> Benjamin Stobbe <benjamin_stobbe@hotmail.com>
Onderwerp: Re: [TRNSYS-users] Question about Type 563 hybrid solar panel

 

Benjamin,
 In order to get at additional values that are computed by the Type you'd need to have access to a Fortran compiler and would have to modify the source code, recompile the appropriate DLL, and modify the proformas.
 
 As for your question about the outlet temperature being below the inlet temperature, bear in mind that the model takes radiation losses into account and that if you have flow at night you can cool the working fluid down by means of radiation loss from the panel surface to the night sky.
regards,
 David

On 08/20/2015 07:31, Benjamin Stobbe wrote:

Dear people,

 

The last week i played around with the Type 563 hybrid solar panel, but i was wondering in the description in the documentation they do a lot more calculations than which are coming out of the model. For example reasons for me to use trnsyst is to see what happens in the hybrid solar panel and I mean the thermal side. The formulas are really clear but if I see what output I can get out of the model I miss some. For example the temperature of the pc cell so how warm will the pv cell becomes this is interesting to know because in that way you can see how much you cool the panel down with the flow of water on the backside.

 

Some results which coming out of the model don’t make sense for  me for example how is it possible that the outlet temperature is lower than the inlet temperature and also lower than the ambient temperature. Looks like the solar panel is cooling the water down and I think this is a bit strange.

 

I hope to hear from you soon.

 

Best regards,

 

Benjamin Stobbe




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