CSP 1-day simulation with SAM

Hi,

I would like to know if it is possible to simulate only 1 day with SAM instead of annual simulations.

If it is not possible, is there any trick to do it, like for example setting DNI to zero in the rest of the days of the year or something similar?

Thanks in advance,
Bosco Olabarri

Dear Bosco,

There is not a simple way to use SAM to model a system's performance for a single day. You might be able to make it work by creating a weather file that consists of 365 identical days of hourly data. To do that, you would need a full set of weather data as described in Weather Data Elements Used by Each Performance Model for a 24-hour period.

I have not tried that approach, so I am not sure it would work.

Depending on what you are trying to accomplish, you could choose a single day from the annual results and ignore results for the other days.

Best regards,
Paul.

Dear Bosco

You might be interested to learn from an experience I had.

I tried using SAM 2013.1.15 to model CSP using a weather file with 8760 values at 10 minute resolution. When I ran the simulation, it did not complete. I discovered that SAM checks the solar irradiance data provided against calculated extra-terrestrial solar irradiance. If the given solar irradiance exceeds the extra-terrestrial value, then it is recorded as a bad value. If too many bad values occur, then the simulation stops.

If the bad value limit were increased or the check removed (perhaps by using the SDK when it includes CSP), then I suppose the simulation would run to completion. Note that SAM was designed for hourly time steps so the results from 10 minute weather values may not be as reliable.

Regards
Edward

Dear Paul & Edward,

Thank you very much for your quick response.

What I am trying to accomplish is to obtain model net electric output with recent DNI data to have a quick estimate of the expected real production of a CSP plant on a daily basis.

I would work on it based on your suggestions and let you know if I can achieve it and how.

Best regards,
Bosco

Dear Paul,

As you said, since that SAM simulations are always for 1 year, the only way to achieve single day simulations is extracting the results for that day from the annual results.

In my case, based on your suggestions, what I did to achieve my particular "1-day simulation" was to modify a standard 365 days meteo file for my location (TM3-CSV format) with the input meteo data of my simulation under the following constraints:

1- It is important to change the input meteo data of the day to be simulated in its corresponding date inside the standard meteo file, e.g. a simulation of the 1st of July gives different results depending where you update the meteo data on the file. I guess this is due to some filtering of values falling outside sunrise/set hours according to SPA algorithm. So that 1st of july data have to be updated on the same date in the meteo file.

2- It is also important to change the meteo data of the previous day. The previous day data is important in order to get the most possible accurate initial conditions for the turbine, HTF temperatures etc. This makes difficult to simulate the 1st of January, since it is the first day of the meteo file.

3-Since HTF Solar Field initial temperature seems to be applied always to beginning of the annual simulation, changing its value does not have any impact on the 1-day simualtion unless for your are simulating the 1st of January.

Once the meteo file is changed, after running the case with SAM, you just need to extract from the annual results, the values of the date being simulated.


Thanks for your help.

Best regards,
Bosco Olabarri

PS: I am using SAM 2009.10.13 due to contractual issues on a CSP PT case without TES