Session: 17-01-01: Research Posters

Paper Number: 150532

150532 - The Need for Rapid and Accurate Performance Metrics for Vertical Building Integrated Photovoltaics 

The building sector significantly contributes to greenhouse gas emissions. In response, net-zero legislation mandates energy-efficient buildings that generate as much energy as they consume. Building Integrated Photovoltaics (BIPV) provide an on-site energy solution. Traditionally limited to roof installations, BIPV faces challenges when energy demand exceeds roof capacity or when roofs are unavailable. In such cases, BIPV can be mounted on building facades.

 

However, comparing BIPV performance for vertical installations is complex. Unlike roof-mounted systems, vertical BIPV panels face varying orientations, lacking standardized metrics. The purpose of this poster is to emphasize the need to investigate current and newly proposed metrics to compare BIPV products designed for vertical installations.

 

A critical issue arises from the lack of standardized specifications provided by companies installing BIPV on facades. Vague information impedes direct product comparison, making it difficult for consumers to make informed choices. For example, some companies cite power range, while others mention  performance under Standard Test Conditions ( an irradiance of 1000 W/m2 with air mass 1.5 and a cell temperature of 25°C) as their main measure of product performance. However, without standardized metrics for vertical installations, these figures remain abstract and do not facilitate meaningful, rapid product comparisons. 

 

While comparing product performance in photovoltaic (PV) vertical installations is not an easy task, these complexities escalate when PV systems incorporate concentration techniques, such as Luminescent Solar Concentrators (LSCs). LSCs act as waveguides that concentrate light on much smaller areas PV, incorporating luminescent species that shift the wavelength of solar radiation to a range more efficiently converted by PV cells. Due to the intrinsic complexity of the light concentration process, developing relevant metrics becomes even more intricate. 

 

This poster presents a summary of existing metrics for BIPV vertical installations currently used by industry, discussing their shortcomings, and proposes new metrics for evaluating vertical BIPV performance. Furthermore, to facilitate rapid product comparison, annual energy production per unit area was determined for crystalline silicon PV installed vertically and facing south, east or west for multiple geographical locations. Preliminary results show, for examples,  that for south oriented vertical PV the production drops at 60%-70% of that of optimum tilt installation reported under STC. This ratio is anticipated to carry over to other PV types. However, such ratio lookup tables are not applicable to more complex BIPVs like those incorporating LSC, which need new metrics, as discussed in this poster. The study also underscores the industry’s need to establish clear specifications that allow customers to compare system performance effectively and rapidly and choose the most suitable solution for their needs.

Presenting Author: Hannah Arnow Rensselaer Polytechnic Institute

Presenting Author Biography: Hannah is a current PhD student at Rensselaer Polytechnic Institute

Authors:

Sara Rizvi Rensselaer Polytechnic Institute
Hannah Arnow Rensselaer Polytechnic Institute
Diana Borca Tasciuc Rensselaer Polytechnic Institute