Auxiliary energy losses

[rcalvo]

Hi,

The PV field detailed system losses parameter in the auxiliary energy losses I have some doubts:

 

based on the following data from manufacturer .OND file

 

1: Inverter Losses:

This is provided by the manufacturer, in the .OND file.

"Continuos auxiliary loss (fans, etc)" Are this the self-consumption losses in operation of the inverter?

"...from threshold on oper. power" in the .OND file it´s called "...from output power". I don´t understand this kind of losses, would you mind to explain in more detail?

2:plant losses:

"Proportional to plan operation power(W/kW)" Are this losses in W per kW peak or nominal? They are the same and continuos losses all hours of the day/year?

"...from threshold o oper.power" Are this losses into account only the hours from threshold on oper. power(operation of inverter)?

3: Nigth Losses:

What kind of losses are this? Why excluding the inverter nigth loss? if the manufacturer set nigth losses (400 W in this case), where I use it?

Thanks.

[André Mermoud]

The Losses for the system indeed may use the inverter's specified losses if available as default values.

But you have to define them explicitely.

The idea in PVsyst is to give sufficient flexibility for defining these losses in the best possible realistic conditions for your system.

Therefore we propose different possible strategies:

- A constant loss (all fans "ON") from a given produced power (it is sometimes not necessary to cool the inverter if they work at 10% of their power).

- Auxiliary loss proportional to the instantaneous operating power (for example fan's speed controlled by the real temperature increase, i.e. the power, or cooling installation which will have more heat to extract with higher powers).

- Night losses of the auxiliaries (fans, controllers, monitoring, etc).

The night loss of the inverter itself, as specified by the inverter's manufacturer, is accounted independently in the simulation and presented independently in the loss diagram (if significant).