*Article* **Long-Term Field Observation of the Power Generation and System Temperature of a Roof-Integrated Photovoltaic System in South Korea**

**Muhammad Hanif Ainun Azhar 1,†, Salh Alhammadi 1,†, Seokjin Jang 1,†, Jitaek Kim 2, Jungtaek Kim <sup>2</sup> and Woo Kyoung Kim 1,\***


**Abstract:** A miniature house roof-integrated photovoltaic (PV) system in South Korea was monitored for 2.5 years. System performance was evaluated through power generation, solar irradiance, and system temperature. The comparison of each month's power generation and solar irradiance revealed a parallel correlation over the entire observation period. The internal module temperature was almost always higher than the roof rear and module rear temperatures by 1–2 and 1–5 ◦C, respectively, while the temperature behind the PV modules was the lowest among the three temperatures, showing that the installation of PV modules as a roofing system does not affect the temperature of the roofing system. The system temperatures affected the power conversion efficiency; a maximum of 11.42% was achieved when the system temperatures were the lowest, and a minimum of 5.24% was achieved when the system temperatures were the highest. Hence, half of the anticipated generated power was lost due to the temperature fluctuation. Overall, installing PV modules as an entire roofing system is possible with this configuration due to the minimum effect on the roof temperature. However, PV system temperature control is essential for maintaining the power generation performance of the PV modules.

**Keywords:** building-integrated photovoltaics; roof-integrated photovoltaics; photovoltaic module temperature; building-integrated photovoltaic system temperature
