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User's needs ("load")

The programme offers a great flexibility to define the energy needs of the user (or the "load" of the system).

NB When you are in a stand-alone system, the option "Household consumption" is open by default. You can get the following options, or a summary of your consumers definition, with the button Other profile.

You should choose among the following options:

  • Unlimited load, which only concerns installations connected to a sufficiently "strong" grid to absorb the whole produced power. This is the default option with grid systems. But this option obviously doesn't make sense with a stand-alone installation, where production and especially battery behaviour are closely related to electricity use.
  • Fixed constant load, offers the simplest way to define user's needs. You just have to define it as constant power or yearly energy.
  • Monthly values gives the possibility of defining monthly averages, which will be used by the simulation as constant over each month (no daily modulation). Values are defined using a special graphic tool.
  • Daily profiles in hourly values can be user-defined using a graphic tool, as:
    • Constant over the year: the same profile all along the year,
    • Seasonal modulation: four specific daily profiles, for each season (defined as June-August, September-November, December-February, March-May).
    • Monthly normalisations: one only daily profile, the amplitude of which being modulated according to given monthly sum values.
    • Weekly modulation: a specific daily profile for "working days", and another one for "week-ends". Each of these staying constant over the year. The number of "Working days" in a week is user defined.
  • Probability profiles are designed for grid applications, when the grid load is not illimited. It is the probability distribution of the power which can be absorbed by the load at a given instant. This is especially suited to DC-grid for public transports. Possible power load is divided into 12 classes of given values; the user specifies the probability distribution values for each hour. This profile can be defined:
    • Constant over the year: the same profile all along the year,
    • Seasonal modulation: one specific daily profile for each season (as above).
    • Weekly modulation: a specific daily profile for "working days", and another one for "week-ends".
  • Daily Household consumers is the default user's needs definition for stand-alone systems. It proposes a list of most usual domestic appliances, with unit power and daily use duration. Values can be defined as:
    • Constant over the year: the same daily load value all along the year,
    • Seasonal modulation: one specific daily load for each season.
    • Monthly definitions: a specific appliance distribution for each month.

NB: With this tool a Weekly modulation option is independently available for each season or month, but only for putting some "week-end" days to zero or standby.
This appliance's definition is mainly thought as a presizing tool for stand-alone systems, in order to evaluate the load from a user's point of view. In presizing, the effective use of the defined values, during the simulation process, is equivalent either to a constant load, or to seasonally or monthly constant values. In detailed simulation, a superimposed daily profile may be defined.

  • Load values read on ASCII file is the most flexible load definition: you can edit your own desired load profile (either in hourly or in daily values) in a spreadsheet editor or any ASCII file, and easily import it in PVsyst.

You can find several templates of usual daily profiles (for household, industry, agricultural use), that you can rescale to your effecive power or annual energy.

Model

With the button load, you can get some template models (*.LOD files).

You can also save your Load profile as a model for reusing it in another project.