Abstract:
Purpose The purpose of this paper is to propose a fixed PV energy system design and a sun tracking PV energy system design to meet the primitive energy demands of a typical house in Sakarya, Turkey with energy payback times (EPBT) and greenhouse payback times (GPBT) calculations. Design/methodology/approach The designs were developed based on the total solar radiation received on the surface of the PV modules. The EPBT and the GPBT of the designs were investigated by utilizing the current embodied energy data of the literature and annual energy output of the proposed systems. The monthly mean total solar radiation, the yearly total solar radiation and the annual energy output of the systems were calculated according to the results of previous studies of authors on 80-W prototypes of a fixed PV energy system tilted at the yearly optimum tilt angle of Sakarya and a two-axis sun tracking PV energy system. Findings The annual energy outputs of the fixed system and the tracking system were established to be 10.092 and 10.311 MJ, respectively. EPBT of the systems were estimated 15.347 years for the fixed system and 11.932 years for the tracking systems which were less than the lifespan of PV modules. The greenhouse gas emitted to produce and install the systems were estimated to be 6,899.342 kg for the fixed system and 5,040.097 kg for the tracking system. GPBT of the systems were calculated to be 5.203 and 2.658 years, respectively. Originality/value PV energy is clean without greenhouse gas emission during the operation. However, significant emissions occur in the life cycle of PV modules until the installation is completed. Therefore reducing the number of PV modules make great differences in the GPBT of PV energy systems. In this paper, comparisons between the GPBT results of the optimally tilted fixed system and tracking system were performed to discuss the best option by means of environmental concerns.
