AUXILIARY ENERGY SAVING POTENTIAL OF SOLAR THERMAL SYSTEMS WITH PREDICTIVE CONTROLS

摘要

Solar thermal systems in residential buildings are generally controlled by two-level controllers, which activate solar thermal energy supply, or at times with low solar radiation auxiliary energy supply. Simple controllers do not have any information on actual or expected solar radiation. This leads to interference of auxiliary- and solar heat supply, which reduces the share of solar thermal energy fed into the thermal storage. Increasing accuracy of weather forecast data suggests incorporation of this information in the control algorithm. This work analyzes the maximum potential performance enhancement when applying such an intelligent predictive control. A solar thermal system for residential use is designed in TRNSYS - this system represents the base case. Further, a number of simulations are conducted with minor variations for the plant parameters - this gives generic results for different system configurations. In addition, each system configuration is altered to mimic the behavior of a plant with intelligent predictive control. Comparison of results indicates an improvement potential up to 10% for annual solar fractions and up to 30% for monthly solar fractions.