[TRNSYS-users] doubt regarding type 74 CPC

[Jeff Thornton]

Aditi, 

Type 74 is a somewhat simple way of modeling a low temperature CPC. A
more detailed model can be found in the TESS High Temperature Solar
Library. The model there considers a time-varying loss coefficient as
well as a more rigorous solution of the differential equations that
result from the fluid properties changing with temperature. Using that
model also requires that you use the accompanying storage tank model,
pipes etc to also account for the property changes. 

If the collector you are considering has been tested to the popular c1
to c6 coefficient approach, we also have models that can replicate that
performance model. 

Jeff 

---
Jeff Thornton
President - TESS LLC
22 N. Carroll Street, Madison WI USA 53703
Office: (608) 274-2577 Fax: (608) 278-1475
www.tess-inc.com
E-Mail: thornton at tess-inc.com

On 11/21/2017 6:13 am, Aditi Garg via TRNSYS-users wrote: 

> Hello everyone, 
> 
> I was working on type 74 CPC. I tried checking the collector outlet temp. for a location and I got temperature up to 600 degree C which doesn`t seem so realistic. In parameters of TYPE 74, the overall loss coefficient UL is fixed as 3kJ/hr.m2.K. 
> 
> Now, UL depends on ambient temperature, average collector fluid temperature and some other parameters as well. 
> 
> So if these temperature are varying with time then the loss coefficient should also vary, which is not happening as I think. So is there any option through which we can modify the loss coefficient ( as a function of temperatures and other parameters) and get some realistic collector outlet temperatures. 
> 
>   
> REGARDS 
> ADITI GARG
> 
> PHD RESEARCH SCHOLAR
> 
> Department of Mechanical Engineering
> INDIAN INSTITUTE OF TECHNOLOGY, DELHI
> 
> Hauz Khas,New Delhi-110016
> 
> India
> 
> Email ID: aditigarg107 at gmail.com
> 
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> TRNSYS-users mailing list
> TRNSYS-users at lists.onebuilding.org
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