HDR Sky Photometer for Fenestration and Daylight Control
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Solution Overview
Problem
Current fenestration control systems struggle to accurately measure and predict sky conditions, leading to inadequate response to changing daylight and weather, resulting in energy inefficiencies and discomfort due to their inability to separately measure direct solar and diffuse sky components, and are costly and complex to integrate.
Innovation Solution
A system utilizing a high dynamic range (HDR) capturer to obtain images of the environment, a mapper to process these images for relevant metrics, and an expert learning system to generate real-time predictions and adjust building systems accordingly, enabling precise control of daylight and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple radiometers and photometers are used to measure sky conditions, then measurement capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple measurement functions (direct solar irradiance, diffuse sky irradiance, and sky brightness) into a single integrated HDR imaging system. The HDR camera captures the entire sky hemisphere in one measurement, replacing the need for separate radiometers and photometers mounted at various orientations. This merging approach maintains comprehensive measurement capability while significantly reducing system complexity.
Solution Approach 2:
The HDR imaging system performs multiple measurement functions simultaneously: it captures direct solar radiation, diffuse sky radiation, and overall sky brightness in a single operation. The single instrument serves universal purposes that previously required multiple specialized devices, including measuring sky conditions from all orientations and detecting cloud features across the entire sky dome.
2Measurement precision
If multiple radiometers and photometers are used to measure sky conditions, then measurement capability is improved, but integration cost increases
Solution Approach 1:
The patent combines multiple measurement functions (direct solar irradiance, diffuse sky irradiance, and sky brightness) into a single integrated HDR imaging system. The HDR camera captures the entire sky hemisphere in one measurement, replacing the need for separate radiometers and photometers mounted at various orientations. This merging approach maintains comprehensive measurement capability while significantly reducing system complexity.
Solution Approach 2:
The system uses digital imaging to create a computational model of the sky radiance distribution. Instead of using multiple physical sensors, the HDR camera captures light information that is then processed to generate virtual measurements equivalent to what multiple instruments would provide. This digital copying approach reduces hardware costs while maintaining measurement accuracy.
3Device complexity
If traditional photometers measure global sky component only, then device simplicity is maintained, but ability to discern clouds from clear sky is lost
Solution Approach 1:
The patent transitions from measuring only the integrated global sky component (one-dimensional summary value) to capturing the full angular distribution of sky radiance (two-dimensional hemispherical map). This dimensional expansion allows the system to resolve spatial variations across the sky dome, enabling cloud detection, cloud position identification, and differentiation between clear sky and cloudy regions while maintaining comprehensive measurement capability.
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 allows for accurate prediction and response to sky-related changes, optimizing energy use, comfort, and reducing integration costs by providing detailed measurements of sky conditions, enabling timely and appropriate adjustments to fenestration and HVAC systems.
Implementation Method 1
an HDR capturer for obtaining an image of a local environment
Data Source
AI summary
Disclosed is a photometer that employs high dynamic range (HDR) image processing and manipulation algorithms for capturing and measuring real-time sky conditions for processing into control input signals to a building's automated fenestration (AF) system, daylight harvesting (DH) system and HVAC system. The photometer comprises a color camera and a fitted fish-eye lens to capture 360-degree, hemispherical, low dynamic range (LDR) color images of the sky. Both camera and lens are housed in a sealed enclosure protecting them from environmental elements and conditions. In some embodiments the camera and processes are controlled and implemented by a back-end computer.