ANALYSIS OF CLOSED LOOP SOLAR ENERGY SYSTEMS BY THE PHI/F-CHART METHOD : EFFECT OF DIFFERENT BRAZILIAN LOCATIONS

Resumen

Preliminary designs or small solar systems require inexpensive methods for predicting long-term performance. The PHI/f chart method combines two approaches. Utilizability can be defined as the fraction of the incident solar radiation that can be converted to useful heat. If only radiation above a critical or threshold intensity is useful, then we can define a radiation statistic, called utilizability, as the fraction of the total radiation that is received at an intensity higher than the critical level. Multiplying the average radiation for this period by this fraction to find the total utilizable energy. By his turn, the f-chart method provides a procedure for estimating the fraction, f, of the total monthly heating load that can be supplied by an active solar energy system. In this work, we use the PHI/f-chart method to investigate the annual energy performance of hot-water solar systems under different climatic  conditions,  for different brazilian locations.  The effect of storage tank heat losses is also investigated.