Investigating the thermal impact of a novel Concentrated Photovoltaic Glazing (CoPVG) system on buildings

Abstract

A building’s thermal envelope is a contributing factor to the building’s energy efficiency. The materialisation of the thermal envelope is a key parameter when determining the thermal effects to the interior spaces of the building. Glazing is perceived as the weakest element in a building’s thermal envelope, however there is great potential to optimise glazing types to enhance building energy efficiency. The use and types of glazing in buildings has significantly increased and developed in modern architecture. The effects increased ratios of glazing in buildings presents to a building’s internal conditions for space heating and cooling are significant.

Standard or traditional glazing such as single or double glazing has been investigated with focus on their specific thermal properties and low or high thermal resistance. The development of these glazing types has attributed to more energy efficient buildings, minimising heat loss. Innovative glazing such as reflective, low-e, dynamic, prismatic and prismatic with PV glazinghave presented the optimisation of the thermal and optical properties and the effects to the building’s internal spaces. Whilst the integration of innovative glazing has presented energy savings, their form can often be difficult to construct, requiring specialist manufacturing processes when compared to traditional glazing types.

This research investigates the effects on building space heating and cooling energy and associated carbon emissions in various climatic conditions when integrating a novel Concentrated Photovoltaic Glazing (CoPVG) system, when considering its thermal and optical properties. The CoPVG: a stationary concentrated PV glazing system that uses Total Internal Reflection (TIR) to concentrate solar radiation to the portion of PV. This system was chosen for this thesis as its simplistic structure differs from many prismatic lenses and its optical and thermal effects as a glazing unit are presented in conjunction to building energy usage.An experiment was conducted to investigate the CoPVG’s transmissivity and its response to varying solar angles. The experimental results are compared against the previous ray-tracing analysis and showed a minor discrepancy of 10% for the transmissivity.

A unique method of modelling the system is introduced, when considering the systems’ varying transmissivity at different solar angles and the effects of diffuse and direct radiation. Further to this, the optimal window to wall ratio is determined for various climatic conditions Computational modelling is employed when investigating the effects of glazing types and used to determine the effects of reflection, glazing thickness, absorption, g-value, thermal resistance, emissivity and transmissivity.

The results from this showed that the CoPVG works particularly well in warmer climates, such as Larnaca, due to its ability to reduce solar gain. An annual reduction of 65.4% in energy for space cooling for Larnaca was demonstrated when using the CoPVG compared to traditional double glazing. In moderate climates where space heating is a predominant energy user in buildings, the results when the CoPVG is integrated present the difference in energy was 32.2% higher when compared to using traditional glazing, due to reduction of solar gain, increasing the heating energy demand. However, this difference is offset by the electrical generation by the CoPVG. A larger window to wall ratio (WWR) for the CoPVG has shown its benefits in warmer climates. This unique method of studying the CoPVG has provided insight on how its adaptations can be modelled and utilised from a commercial point of view for architects, designers and researchers.

Thesis is embargoed until 30 June 2027

Date of Award	Jun 2025
Original language	English
Supervisor	Mervyn Smyth (Supervisor), Jayanta Mondol (Supervisor) & Aggelos Zacharopoulos (Supervisor)