Comparison of theoretical and real energy yield of direct DC-power usage of a Photovoltaic Facade system

Multifunctional facade components have nowadays become a significant research topic as a step towards developing energy-efficient buildings. This paper presents the performance evaluation of an experimental setup of a real fully decentralized fa cade-integrated photovoltaic (PV) system installed in a prototype facade, for direct DC power use. The goal of this evaluation was to test the system's ability to fulfill a pre-designed daily electrical load of 925Wh corresponding to a three-people office space under 100% decentralization. This was achieved by studying the operation under different weather conditions and the impact of the system design and components on its overall output. The evaluation of both the actual and theoretical system outputs indicates poor actual system performance in terms of low energy yield and unacceptable load fulfillment factor, which did not exceed 0.95. At the same time it revealed underutilized system potential which could be exploited theoretically with a proper system configuration. The results in this paper conclude that decentralized facade integrated PV systems can completely satisfy their designated applications if properly-designed and implemented, and provides a methodology which could be used in designing similar systems. Satisfactory fulfillment is shown to be achieved by having 30% additional PV and 9 times bigger storage capacities in this system. (C) 2015 Elsevier Ltd. All rights reserved.