The Investigation of Impacts and Power Values from PV Grid Connection

One of indirect benefits for installing PV-rooftop system is heat reduction into the building which leads to cooling load reduction duo to PV-shading. This research studies heat reduction by shade of PV module installation on metal sheet roof building in Bangkok. 5-years data collection, ambient air temperature, exposed roof temperature, underneath PV module roof temperature, stable solar irradiance in ten minutes and wind speed information were picked up for one year evaluation. There are classified the days in different seasons into four characteristics, regrading ambient temperature and solar irradiance. The result reveals that high ambient temperature, averaged 33°C, and high solar irradiance, 6.65 kWh/m2/day, accounted for 81% of the days in 2019, are the most benefit for project owner because of reducing air condition demand. This condition, shading from PV module, could reduce heat transfer to the roof around 5.64 KJ/m2 or equivalent to electricity saving by the shade of PV module 0.047 kWh/m2 or 0.424 kWh/m2/day. This research could apply for cooling load calculation of the building installed PV system on the roof. Moreover, it might support the decision making for installing PV-rooftop system and being as a factor for setting up new policy, promoting the residential PV installation.