Impact of shading on a flat CPV system for façade integration

Abstract

Recently adopted energy efficiency policies in the EU induce a movement towards energy-neutral buildings. Building integrated photovoltaics technology connects with this ambition, as aside from the generation of electrical energy, it allows additional benefits such as heat generation, or daylight regulation by transmission of diffuse sunlight through transparent parts of the system. In this study three Concentrator Photocoltaic (CPV) system configurations that allow for the construction of semi-transparent building façade elements are investigated outdoor. The systems are a Fresnel lens based concentrator, a novel flat planar optic concentrator, and a 4x4 panel of these flat optics. The flat optic has no air cavity to account for optical focal depth which is highly beneficial when incorporated in a window. In particular the energy production of the systems when partially shaded is investigated, as adjoining systems will move behind one another during sun tracking, because the optics spacing must be small to achieve good daylight regulation. The planar optic concentrator is found to display similar performance as a Fresnel lens based concentrator of similar concentration. For a multi-receiver panel, shading introduces a loss of performance ranging from 7 to 12% which is attributed to electrical interconnection as individual receivers do not suffer this loss.

Design and testing of highly transparent concentrator photovoltaic modules for efficient dual‐land‐use applications

“…Notably, a portion of diffuse sunlight can be absorbed by the solar cells; however, the portion is negligibly small (less than 0.1% of total diffuse sunlight) in the case of high-concentration CPV (geometrical concentration ratio >100×) according to the acceptance angle limit of the solar concentrator. 15 Similar concepts have also been reported for building windows [16][17][18] and greenhouses. 19 Tripanagnostopoulos et al 16 proposed a CPV/thermal hybrid system with a Fresnel lens for building façades and experimentally evaluated the (a) temperature control performance of the building's interior space, (b) illumination control of the interior space, and (c) energy-harvesting performance (PV characteristics and heat collection) of the system.…”

“…Similar concepts have also been reported for building windows and greenhouses . Tripanagnostopoulos et al proposed a CPV/thermal hybrid system with a Fresnel lens for building façades and experimentally evaluated the (a) temperature control performance of the building's interior space, (b) illumination control of the interior space, and (c) energy‐harvesting performance (PV characteristics and heat collection) of the system.…”

A literature review on Building Integrated Solar Energy Systems (BI-SES) for façades − photovoltaic, thermal and hybrid systems

“…During the tests, the efficiency of the photovoltaic module increased by about 7% (reaching an h e of 22%). In Bunthof et al [47], they build up the examination dependent on three Concentrator Photovoltaic (CPV) systems arrangements that consider the development of semi-straightforward structure veneer components. The systems likewise are a Fresnel focal point based concentrator and a novel level planar optic concentrator.…”

Performance Assessment of Concentrated Photovoltaic Thermal (CPVT) Solar Collector at Different Locations

“…One of these challenges is partial shading which (Decker and Jahn 1997) have investigated. Furthermore, (Bunthof et al 2016) showed that partial shadowing is the primary parameter for decreasing the energy yield of PV arrays. (Woyte, Belmans, and Nijs 2003) studied one possible solution to overcome this challenge by using bypass diodes which allow PV arrays to produce at a lower capacity.…”

“…In this method, electrical current flows in a different path, and this causes a minor fraction of the total power. (Bunthof et al 2016) conducted a study that shows costs of the solar collectors increased by adding bypass diodes to the PV arrays. Considering all these parameters, this study focuses on a PVT receiver without a bypass system.…”