Pumping System Oversized Pump & Undersized Pump Coexisting Error

[Ben_Duffy52]

Hi there,

I'm having trouble modelling my groundwater pumping system in PVsyst. 
If I set my Pumping Hydraulic Circuit parameters as follows below:

And my pump and PV setup as below:

I recieve the following error (and the pump is unproductive almost all of the time):

However if I try to increase the depth of the 'Lower dynamic level' at all, or decrease the specific drawdown at all I receieve the following error:

 

If I'm not able to either decrease the drawdown or make the lower dynamic level lower to try and make up for the fact that the pump is supposedly oversized for the well, I'm not sure how I can solve this problem? (FYI for this theoretical project it is acceptable to modify the parameters within reason, the pump level and static level are based on the real pump however.)

Further, it is suggesting that I need a PV array of 2160 modules, which seems very excessive for an agricultural water pump (which is based on a real life grid electric pump of unknown pump brand which is known to work well).

Thank you in advance for any help, it is much needed!
Ben

[Muhammed Sarikaya]

Dear Ben,

First of all, in defining the water needs, you specified a maximum flow rate of 8 m³/h. However, the selected pump operates between 40 m³/h and 200 m³/h. Don't you think the pump is oversized for the well?

Even if you install the pump at depth, the water availability won't change; the well's resources only allow for a flow rate of 8 m³/h maximum.

In real operation, the pump will frequently start and stop because the water level will drop to the level of the pump, and a pump should never operate without water.

I suggest you consider replacing this pump with one that has a lower flow rate, more suitable for the well's capacity.

Regards,

Muhammed Sarikaya

[Ben_Duffy52]

Hi Muhammed Sarikaya,

Thank you for your reply. When I replace the pump with any with a lower flow rate I then get the error below.

At the same time, when I increase the max flowrate of the water source to 42m^3/h, I then get the following error: 

And then as far as I can tell there are no pumps that can supply 918meterW. 

Is it possible that the parameters I have put in for pipe length (1800m) and pumping height (about 300m) are just too great for any of the pumps in the system to handle?

If not is there something that I'm doing wrong here?

I look forward to your reply.

All the best,
Ben

[Ben_Duffy52]

P.S. If you have any suggestions for combinations of values I could insert for the max flow rate, dynamic level and drawdown that would allow my system to work with any pump that would be greatly appreciated!