Performance Evaluation of 780 Wp Rooftop Solar PV Power Backup System in Western Kenya

Aim: This study aimed to carry out performance analysis of a 780 Wp PV power backup system installed at a learning institution in Western.

Study design: To achieve this goal, site solar radiation received, ambient temperatures, dc current and dc voltages were measured in order to carry out performance evaluation of the PV backup system.

Place and Duration of Study: Department of electronics and electrical, Kaiboi Technical Training Institute in Nandi County, western Kenya was studied, between January 2020 and December 2020.

Methodology: Performance of any PV system depends on the operating conditions (solar radiation, ambient/module temperature, etc.) available at the site (geolocation dependent), installation (tilt and orientation) of the arrays, and finally proper system sizing (PV array, battery, BOS). In this paper, standard performance parameters reported in literature were utilized to evaluate the performance of the studied PV backup system. The array comprises of four panels interconnected in series/parallel to produce an output power rating of 780 W. A Pyranometer was mounted on the plane of array (POA) to measure solar radiation intercepted by the PV array where daily data were acquired at an interval of five minutes. I-v data were also recorded. Different literature was reviewed to identify the way to do this work.

Results: Based on the performance of the studied PV system, results obtained show that annual effective energy output is 3412.94 kWh, array efficiency range between 11.6% to 14.1% depending on amount of solar radiation, array yield of 4.88 kWh/kW, reference yield of 5.5 kWh/kW, annual average performance ratio of 76.3% and average array capture losses of 0.52 kWh/kW.

Conclusion: It found that the PV backup system need ~5-6 hours to operate at the array’s rated output power, and that the PV backup system performance is adequate with regard to yield and performance ratios.