Improving solar PV system efficiency using one-axis 3-position sun tracking

The energy conversion efficiency of commercial solar PV is around 15-19%. Millions of dollars are spent in order to gain a small percentage in energy conversion efficiency. The power generation of solar PV can be increased using sun tracking technology. However, the design of the sun tracker is usually very complicated and expensive. Units are heavy and prone to breakdown and installation is difficult. In the present study, one-axis three-position (1A-3P) low-cost sun tracking PV as a BIPV was developed and tested. The comparative test of a 1A-3P tracking PV system started from 2010/3/01 was carried out. The single-day increase of energy generation is 39% in clear days. The overall increase of total energy generation from March 1, 2010 to May 31, 2012, is 24.2% in Taipei. The expected overall increase of total energy generation with respect to fixed PV is 37.5% in high solar radiation areas. The installation cost of 1A-3P sun tracking PV is about the same as the regular mounting cost of a conventional rooftop PV system, but providing 25-37% higher PV energy generation efficiency. For cost reduction in structural design, the wall mounting of 1A-3P tracker may cause PV not facing south exactly. A long-term comparative field test was carried out to study the effect of misalignment using three identical 1A-3P tracking PV module facing south, southeast 45o, and southwest 45°. The measured energy loss is 4.42∼6.82% for southeast orientation and 4.31∼6.79% for southwest orientation. The test result shows that the energy loss of 1A-3P PV due to misalignment of south is negligible. Many samples of 1A-3P trackers were manufactured and installed for field test. The longest test is over 30 months with satisfactory performance.