Development of a design support tool for an innovative building-integrated concentrating photovoltaic façade system

An increasing energy demand from the continuously growing population has triggered an inevitable increment in the energy demand of buildings, which has motivated the transition towards sustainable and smart cities, focused on the design of healthy, energy efficient and aesthetic environments. In recent years, the evolution towards a more sustainable built environment has been taking place and it is imperative that this trend continues.

One of the companies that contributes to this trend is Wellsun, with its signature product Lumiduct, which provides an integrated solution for energy generation and indoor thermal and daylight comfort of buildings. This innovative building-integrated concentrating PV (BICPV) façade system consists of a double-skin façade with an array of movable panels located in its cavity, which track the sun during the day. This optical system treats the diffuse and direct part of solar irradiation in a different manner. The diffuse component freely passes through the modules and reaches the room as soft daylight. The direct part, on the other hand, is concentrated onto tiny, ultra-high-efficiency III-V solar cells to generate electricity. By virtue of the complexity of this technology, Lumiduct provides many functions to a glazed façade, as it reduces solar gains, protects against glare, generates electricity, lets daylight in, and allows for a view to the outside.

During the research and development of this technology in the past years, the various benefits of Lumiduct have been proven and validated with experimental work. However, there is a need to further improve the understanding of the technology and its corresponding value proposition, as the Lumiduct performance is specific for a given building design, location and so on. In order to do so, it is important that the Wellsun team can communicate the multi-dimensional performance of Lumiduct to architects, engineers, building owners, investors and other stakeholders. By doing so, they can position themselves in the market with respect to competitor technologies.

The objective of this project was to develop a computational design support tool (DST) that provides a straightforward way of analysing the performance of the façade system for different building design variants and under different environmental conditions, helping Wellsun to communicate the potential of this technology. The functional requirements were elicited by ensuring that the Lumiduct DST is meaningful, reliable and accessible. The tool developed has been built on top of an integrated simulation model for building performance that accounts for the behaviour of Lumiduct in different physical domains. The development of the simulation models and their automation is described in detail. The quality of these model predictions has been assured through comparisons with a full-scale pilot façade system. The analysis and visualization of the system performance has been determined based on insights obtained from literature, analysis of the potential users and stakeholders and other available design support tools, following a design thinking strategy. The application of the Lumiduct DST is presented through two scenarios, one focused on an orientation study for the Dutch market and another discussing the potential for a ventilated Lumiduct façade in a warm climate. Furthermore, this tool was designed to be easily updatable and extendable to meet the requirements of other stakeholders, motivated by the fact that both the technology and the requirements and expectations are continuously evolving. By maintaining the high-resolution simulation models and the database as the back-end of the tool, different front-ends (user interfaces) can be developed for various audiences in the future, as the provided inputs and key performance indicators that result from the computational models can be carefully selected depending on the targeted end user.