Abstract
PV-Battery systems are commonly sized based on the lowest solar radiation of the site of implementation. This implies that during days of high solar radiation excess energy is available. This study investigated the potential of excess energy for thermal storage from PV systems for a case of a rural health center. The system components of a typical PV installation in a rural health center in Tigray, Ethiopia, were considered. The electricity load profile of the health center and solar radiation data available from Mekelle city were used as inputs to a TRNSYS model. Analysis of excess energy in the system at hourly and ten-minute time intervals was conducted. The analysis results indicate that during the months from September to May excess energy was available that could be thermally stored and utilized. During these months, the excess peak power ranged from 737 to 841 W and daily average excess energy ranged from 2070 to 2959 Wh. In contrast, in the months from June to August, no excess energy was available due to low solar radiation.