Sensitivity of long-term performance simulations of solar energy systems to the degree of stratification in the thermal storage unit

This paper investigates the sensitivity of the long-term performance simulations of solar energy systems to the degree of stratification in both liquid and packed-bed storage units. The degree of stratification is controlled by the number of nodes used in a finite-difference approximation of the storage system temperature distribution. Short- and long-term simulations of typical water heating and solar thermal power plant systems are conducted. The results indicate that the long-term performance of these systems is far less sensitive to the number of nodes used to represent the degree of stratification than expected based on short-term simulations or experimental data. An explanation is offered for this non-intuitive result. Copyright (C) 2007 John Wiley & Sons, Ltd.