Experimental Evaluation of a Concentrating PV/Thermal Glazing Façade Technology

The Renewable Energy Framework Directive sets a target of 20% for renewables by 2020. Buildings account for 40% of the total primary energy requirements in the EU and are responsible for 30% of the generated greenhouse gas emissions. Therefore, developing effective solar energy technologies which can be integrated into buildings and provide heat, electricity and/or reduce energy needs, is vital to achieving the set targets. While a range of technologies are available at the moment for building integration most of them are simply super-imposed on the building structure rather than becoming an essential part of it. This does not allow for the full advantages of building integration to materialise as it does not reduce costs by replacing conventional building materials and components. A Concentrating PV/Thermal Glazing (CoPVTG) façade technology that combines glazing based solar concentrating elements, coupled with PV/Thermal absorbers has been developed and experimentally evaluated at the Centre for Sustainable Technologies of the University of Ulster. As a modular multifunctional building component based on conventional double glazing, the CoPVTG is designed to be compatible with traditional façade structures and fenestration framing arrangements, facilitating direct integration into new and retrofit building applications. It can provide solar generated electricity and air heating through the PV/T absorbers while insulating the building thermally. The glazing based concentrating elements are designed to allow the sunlight to enter the building and provide natural daylight when required while redirecting it onto the PV/T absorbers to generate electricity/heat when solar gains need to be minimised to reduce cooling demands.A CoPVTG prototype unit has been fabricated using opti-white glass sheets. The concentrating elements have been cut onto the surface of one of the glass sheets and the PV/T absorbers have been attached using opti-clear silicon. The experimental performance of the prototype has been investigated under a solar simulator. Generation of electricity and heated air has been determined for two directions of the incident solar radiation. The CoPVTG is an innovative multi-functional building component that can contribute to the electrical and thermal building needs while reducing its heating and cooling loads.