Journal of the Korean Solar Energy Society ISSN:1598-6411(Print) 2508-3562(Online) 한국태양에너지학회 논문집

Photovoltaic (PV) systems are commonly used as on-site electric power generators for ZEBs in the Republic of Korea. To enhance the performance of PV systems, considering efficient installation conditions, such as the optimal azimuth and tilt angles, is critical. Under domestic PV application guidelines, the azimuth of installation for building-applied PV systems is stipulated within a maximum of ±90° based on the south-facing direction. In general, the north-facing direction is known as a weak position for PV systems. However, several studies have shown that the north-facing direction can be a good option for building PV installations, typically when the installation areas are limited within a building site. Even if the PV panel faces north, the system can operate effectively with proper performance when installed at a suitable inclination angle. In existing studies, system behavior has been verified based on simulation-based analysis, but actual operational data analysis remains insufficient. This study aims to evaluate the feasibility of north-facing PV systems based on a performance evaluation of the measured data of a roof PV system. The roof PV system analyzed in this study was composed of modules, module-level power electronics (MLPE), and one inverter. The PV modules and MLPEs were installed on both the southern (SIR) and northern (NIR) inclined roofs. Based on the annual cumulative DC power, the energy yields of the MLPE connected to modules of the SIR and NIR are 1,445.0 and 1,068.7 kWh/kWp, respectively. Our study found that the ratio of the performance of MLPE on the NIR to MLPE on the SIR was 74.0%. This ratio was similar to the energy yield of the PV system on the south vertical plane as compared to that on the south slope plane. The analyzed results revealed that an acceptable performance of the PV system installed on a northern slope at a suitable inclination angle could be expected as compared with other PV installations such as the southern vertical.