MSPT Cooling System

Hello Paul,

I'm trying to understand how cooling system affects the performance of a Molten Salt Power Tower in SAM.
When using Air-cooled system I find no problem, but when using Evaporative system, SAM gives me a negative "Annual Energy" and an giant PPA price. I'm using wet bulb temperature, reduced pressure (0.087bar) and changed cycle thermal efficiency. Is there any other input that should be changed between air-cooled and evaporative cooling systems?

Thanks again for your help,
Javier.

PD: I've attached SAM and wheather files. In SAM file, you should go to "SUBC (WC)" case. 

Hi Javier,

Does the information in this post help answer your question?

sam.nrel.gov/forum/forum-general/1993-how-does-the-approach-temperature-of-cooling-water-affect-the-power-cycle-efficiency-of-csp-plant.html#6217

Best regards,
Paul.

Hi Paul!

Thanks for the link, it's a very detailed explanation!
I've had a look at that problem, but I find that I'm working in that condenser temperature range. This is my case:

Ambient temperature at design: 22ºC (Wet-bulb temp)
Reference condenser water dT: 10ºC
Approach temperature: 5ºC

I've also increased the cycle thermal efficiency from the dry-cooled case (41.3% to 43%), but I still find the same problem.
I've checked the weather file and realized there is no "wet-bulb temperature" data (Location and Resourse / View data) when you try to graph it. Is it possible?

Thank you again, and best regads,
Javier

Hi Javier,

As described in the "Weather Data, Weather Data Elements" topic of the SAM Help system, when the wet-bulb temperature is missing from the weather file, SAM calculates it from the dry-bulb temperature, atmospheric pressure, and relative humidity values in the weather file, but unfortunately does not report the result.

Best regards,
Paul.

Hi Paul,

Okay, now I see it!
But still I have the same problem with de cooling system. Could you help me?

Thank you again,
Javier

Hi Javier,

I have asked the CSP engineers for a sample file for wet cooling and will let you know when I hear back from them.

Best regards,
Paul.