[TRNSYS-users] Problem for simulating Rankine cycle powre plant

[Jeff Thornton]

Jiyun, 

The fix to the steam subroutine has been made to the latest version of
the software (Version 18). Version 17 is no longer supported. If you
have access to a FORTRAN compiler, and are comfortable rebuilding the
TRNSYS DLL, I can send you the details as to which line of the code to
fix. 

As I mentioned in my last reply to your question, the steam-to-steam
heat exchanger model can be used if you find the controls of the
feedwater heater to restrictive. Or you can expand the steam leaving the
first feedwater heater and use it as an input to the second feedwater
heater (as happens in real life). 

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 07/30/2018 10:35 am, qin.jiyun--- via TRNSYS-users wrote: 

> Hi Jeff, 
> 
> Sorry to email you again. 
> 
> I just want to know that when the testing process will be completed? So I can uploaded it. As my version is TRNSYS 17, can I upload the new version of this library? 
> 
> For my second question, I still have a question. You told me that I simply connect the outlet steam from the feedwater heater to the inlet flow to the next feedwater heater. However, the Type 622 uses TTD method to calculate the condensate flow outlet temperature and DCTD method to calcuate the outlet temperture of steam. If I connect the outlet steam from the feewater heater to the inlet flow to the next feedwater heater, the proporties (e.g. pressure, temperature, enthalpy) of the inlet steam to the next feedater heater would be changed. Then, How can type 622 to calcualte the condensate flow outlet temperature by using TTD method? 
> 
> Best Regards, 
> Jiyun Qin 
> 
> -------------------------
> 
> FROM: Jeff Thornton via TRNSYS-users 
> DATE: 2018-07-25 03:34 
> TO: trnsys-users 
> CC: Jeff Thornton 
> SUBJECT: Re: [TRNSYS-users] Problem for simulating Rankine cycle powre plant 
> 
> Jiyun, 
> 
> For some reason, the combination of your settings caused a floating point problem in the Steam subroutine. We have identified the problem, have fixed it, and are now testing it. When that process is complete, we will release it in an updated version of TRNSYS 18. Our apologies for the bug. 
> 
> As for your second question. The feedwater heaters can be cascaded without issue. Simply connect the outlet steam flow from the feedwater heater to the inlet steam flow to the next feedwater heater. 
> 
> 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 07/24/2018 11:16 am, qin.jiyun--- via TRNSYS-users wrote: 
> Dear Someone, 
> 
> I'm using TESS library to build a 300 MW subcritical regenerateive Rankine cycle power plant with seven closed Feedwater heater and one deaerator. I have a problem for simulating the feedwater heater system of power plant. I found that when I add the Type622 component in the model, the model woule be got stuck, and if I delete the Type622 component, the model can be run. I find that there are no linking or setting problem of my model. What's the problem of my model? Please find attached model. 
> 
> I have another question about Type622. I found that there are no inputs for drain steam from higher pressure feedwter heaters. Is this means that TESS library can not be used to simulate the Rankine cycle power plant with more than one closed feedwater heaters? 
> 
> Best Regards, 
> Jiyun Qin 
> 
> -------------------------
> 
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> TRNSYS-users mailing list
> TRNSYS-users at lists.onebuilding.org
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