Photovoltaic Skylight Light-Steering for Daylighting and Heat Gain
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Solution Overview
Problem
Existing skylights with integrated photovoltaics face inefficiencies in converting diffuse light to electricity and suffer from heat gain and glare issues, limiting their effectiveness in daylighting and energy generation.
Innovation Solution
The integration of vertically positioned solar panels with refractive glass elements, such as holographic optical elements and glass prisms, that steer direct sunlight towards solar panels while allowing diffuse light to pass through for daylighting, reducing heat gain and improving energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If photovoltaic cells are integrated into skylights to generate electricity, then energy generation capability is improved, but heat gain and glare issues worsen
Solution Approach 1:
The skylight system is segmented into distinct functional zones: photovoltaic cells positioned at the periphery for energy generation, and a central transparent or translucent area for daylighting. This segmentation allows each zone to perform its primary function without interfering with the other, reducing heat gain and glare in the daylighting area while maintaining energy generation capability.
Solution Approach 2:
Different regions of the skylight are assigned different optical and functional properties. The peripheral regions contain photovoltaic cells with high light absorption properties for electricity generation, while the central region maintains high transparency or translucency for daylighting. This local differentiation allows the system to simultaneously generate electricity and provide natural lighting without the harmful effects occurring in the daylighting zone.
2Ease of manufacture
If photovoltaic cells are positioned horizontally in traditional skylights, then integration is simplified, but conversion efficiency of direct sunlight deteriorates
Solution Approach 1:
The photovoltaic cells are repositioned from a horizontal plane to a vertical or angled configuration at the periphery of the skylight. This dimensional change allows the cells to be oriented perpendicular to incoming direct sunlight, maximizing the angle of incidence and conversion efficiency, while still being integrated into the skylight structure through peripheral mounting.
Solution Approach 2:
Optical elements such as lenses or reflectors are introduced as intermediaries to redirect and concentrate direct sunlight onto the photovoltaic cells. These optical mediators enhance the amount of direct sunlight reaching the cells, thereby improving conversion efficiency without requiring complex repositioning of the cells themselves.
3Power
If photovoltaic cells cover the entire skylight surface, then energy generation is maximized, but daylighting quality deteriorates
Solution Approach 1:
The skylight surface is divided into functional segments: peripheral zones dedicated to photovoltaic energy generation and a central zone dedicated to daylighting. This segmentation ensures that sufficient open area remains for high-quality natural light transmission while photovoltaic cells generate electricity from direct sunlight at the edges, achieving both goals simultaneously.
Solution Approach 2:
Different optical properties are assigned to different regions: the central region maintains high transparency for superior daylighting quality, while peripheral regions contain photovoltaic cells for energy generation. This local quality differentiation allows the system to optimize both daylighting and energy generation in their respective zones without compromise.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution achieves an 84% reduction in heat gain and enhances daylighting quality, generating electricity while minimizing the reliance on the electrical grid, with a lower levelized cost of electricity and improved alignment with peak energy demands.
Implementation Method 1
refractive glass, for steering direct light toward the solar panels
Implementation Method 2
solar panels comprising one or more photovoltaic cells to collect direct radiation from rays of sunlight entering the skylight for conversion to electrical power
Implementation Method 3
reflect diffuse radiation to provide daylighting in the building
Data Source
AI summary
A skylight for a building includes a solar panel arranged within the skylight, the solar panel comprising one or more photovoltaic cells to collect direct radiation from rays of sunlight for conversion to electrical power, and an optical element to receive the direct radiation and refract it to the solar panel, and to receive the direct radiation and diffuse radiation scattered from the rays of sunlight and refract the direct radiation and the diffuse radiation through the skylight, bypassing the solar panel, to provide daylighting in the building.