Temperature range used as input for design: low, average or extreme?

[clima]

Hi I'm new using PVsyst and i want to know which temperature range is required as input to the system, i.e low, average or extreme temperature data? When I import the temperature using the system meteo data it seems that only the "average" temperature is registered and I wonder if we shouldn't be using the "extreme" temperature range instead since this might affect the system energy production throughput? Thanks for any help here.

[André Mermoud]

The temperature specifications during the sizing - which you specify in the "Project's parameters, button "Albedo-Settings" - is only used for sizing purposes.

It should give indications about the number of PV modules in series.

You have a full explanation in the help "Project design > Grid-connected system definition > Array voltage sizing"

- The "Lower temperature for absolute values" concerns the safety of the system: it is an "absolute" limit value.

- The "Winter, Normal and Summer operational temperatures" have a low importance during the design (see the graph in the help or on the sizing tool). You can slightly overcome the MPP voltage limits without significant losses.

The final test of the validity of your choice for the number of modules in series will be the Inverter loss below the minimum and over the maximum voltage during the simulation (on the loss diagram).

NB: During the simulation, the array temperature is determined from the hourly ambient temperature and the irradiance, using a little energy balance model.

[clima]

Hi André, thank you for your kind answers. My question is about:

Geographical Site Parameters --> Required Data --> "Average Ext. Temperature?"

What is "Ext" means above? Is "external" or "extreme"? It is the air temperature? Average Temperature (between the max and min)?

I mean if I input the temperature manually instead of using Meteonorm 6.1, should I use the "air temperature" for instance:

Jan (25.3 C), Feb (25.5C), Mar (25.6C)....Dez (25.4C). Annual Ave Temp ©: 24.8 or the average "high" example: Jan (34C), Feb (33C), Mar (31C)....Dez (31C)?

If I use Meteonorm 6.1 to input this automatically does it provide a good value?

Thanks for your help

[André Mermoud]

This is another question.

Here Ext is for "external" indeed.

The waited value is the ambient dry bulb temperature, averaged over the month. A realistic daily profile will be constructed by the Synthetic hourly data generator, taking the concomitent irradiance into account.

This will construct a sinus-like profile, with amplitude about proportionnal to the daily irradiance, and a delay of 2-3 hours (i.e. by clear day, the peak temperature is around 15H (solar time)).

This model waits for the real average over 24H, not the "Average Daytime Temperarture" proposed by some databases.