Sensitivity Analysis of the Useful Energy Output from Solar Converters as a Function of the Type and Time-Step of Meteorological Data

Summary

This study is part of a European Concerted Action (Mr KOCH, KFA Jülich) and will help to answer two important questions : What si the accuracy of the useful energy output calculation according to the kind and time step of the meteorological data sets ? and subsequently:

How can these data be reduced to compute faster but accurately the useful energy output ?

For a set of meteorological data at short time steps as large as possible (Bourgoin Jallieu , Paris = 44 days, Jülich = 270 days and other data from Trappes, Carpentras, Ukkel) a reference useful energy output is defined with MINERSOL for the DRU collector (used in the PTF) and an Evacuated Tubular Collector. It is compared to results derived with :

• either a simpler model (no inertia)

• or a smaller data basis (only averages over larger time steps or frequencies of values).

The comparison shows discrepancies up to 20 % due to the reduction in the model or in the data, largely climate-dependent : for the usual computation procedure and the usual hourly data basis both tendancies do compensate in Central Europe climates ; for other climates corrective terms are still to determine but the effects are under 10 % most cases.