[TRNSYS-users] Steam Boiler's required energy

[Jeff Thornton]

First of all let me say what a pleasure it was to open a project where
the user has obviously taken a lot of time to make the project legible
and easy to follow! Now to your problem. What it comes down to is that
all of the steam components take enthalpy and pressure to set the steam
state (as T and P aren't always indicative of the state). So when you
hooked up the outlet temperature and flow rate from the collector to the
boiler, and left pressure and enthalpy unconnected, the model took the
constant values of the unconnected inputs for P and H and set the steam
state. I have modified your project to include a simple fix (using the
steam properties model to set the state) and a more detailed fix where I
replaced the non-steam models for the mixer and diverter with the steam
versions. Take a look at the differences and choose the method that fits
your needs. 

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 08/22/2018 10:35 am, ­김지혁[기계공학부] via TRNSYS-users wrote: 

> I have designed a PTC power plant. 
> 
> I applied a Tempering valve to control working fluid's direction. 
> 
> If Tout_LPC is lower than Tout_pump2, working fluid won't pass through LPC and will go to the steam boiler directly. 
> 
> However, if Tout_LPC is higher than Tout_pump2, it will go to the steam boiler via LPC. 
> 
> In the 2nd case, Tout_LPC is higher than Tout_pump2, Tout_LPC is 200 degree that is higher than Tout_Pump2, 115 degree. 
> 
> It means that inlet temperature of the boiler is higher(200>115) when the working fluid passes through LPC. 
> 
> So I anticipated that I can save energy for heating up the working fluid in the steam boiler. 
> 
> But I verified that its result is not like it. 
> 
> Required energy in the steam boiler is identical in both cases, passing through LPC and going to the boiler directly, even though the first case's inlet temperature of the boiler is higher than the other one. 
> 
> What is a problem? What parameter should I change? 
> 
> Thanks 
> 
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at lists.onebuilding.org
> http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org [1]
 

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