Optical Humidity Sensors for Building Energy Performance and Air Quality Control

As novel building envelopes are implemented to reduce energy use, indoor air quality can be compromised. Humidity sensing must be part of any advanced indoor air quality system, but existing humidity sensors do not maintain accuracy over extended periods of time, so a humidity sensing technology with long- term stability and costs competitive with current sensor products is needed. Luminescence-based optical sensors for relative humidity are proposed, featuring unprecedented long-term stability, extremely high resistance to airborne contaminants, and no water retention, at a cost similar to those of commercially available sensors. Two key innovations will be combined: a passive material doped with a luminescent dye for enhanced stability, and implementation of a family of circuits that process analog signals on low-cost 100% digital components. Phase I demonstrated the feasibility of highly stable luminescence-based optical sensors for relative humidity. Studies of selected IOS sensors and several commercial humidity sensors under stress conditions revealed the superior stability of the IOS sensor elements. Fabrication protocols for high rate production were evaluated, and the feasibility of sensor manufacturing at a competitive cost was established. The electronic design of the digital chip for processing the luminescent signal was established, the first step toward a low cost electronic device. Though the optical sensors selected in Phase I already showed better stability than COTS sensors, there is still significant room for improvement. In Phase II we will perform sensor material optimization, and evaluate the sensor for stability under stress conditions for extended periods, and will optimize humidity sensors. The first demonstration unit of the electronic device will be designed, fabricated, and validated, incorporating the novel digital chip for processing the luminescent signal. Extended validation and comparison with COTS sensor devices will be conducted in the laboratory under a realistic range of environmental conditions and finally in selected field studies, in collaboration with our commercialization partner. Humidity measurement finds broad use in many industries, such as in process controls, food storage and refrigeration, quality control, homebuilding, heating, ventilation, and air conditioning, medical, healthcare, and automotive fields. The humidity monitoring market can be divided into low ppm moisture monitoring applications, mainly found in the process industry market, and ambient relative humidity monitoring applications, mainly in non-process industries where ambient humidity is monitored and controlled. IOS luminescence-based sensors will be adapted to serve both categories of markets. As novel building envelopes are implemented to reduce energy use, indoor air quality can be compromised. Humidity sensing must be part of any advanced indoor air quality system, but existing humidity sensors do not maintain accuracy over extended periods of time, so a humidity sensing technology with long- term stability and costs competitive with current sensor products is needed. Luminescence-based optical sensors for relative humidity are proposed, featuring unprecedented long-term stability, extremely high resistance to airborne contaminants, and no water retention, at a cost similar to those of commercially available sensors. Two key innovations will be combined: a passive material doped with a luminescent dye for enhanced stability, and implementation of a family of circuits that process analog signals on low-cost 100% digital components. Phase I demonstrated the feasibility of highly stable luminescence-based optical sensors for relative humidity. Studies of selected IOS sensors and several commercial humidity sensors under stress conditions revealed the superior stability of the IOS sensor elements. Fabrication protocols for high rate production were evaluated, and the feasibility of sensor manufacturing at a competitive cost was established. The electronic design of the digital chip for processing the luminescent signal was established, the first step toward a low cost electronic device. Though the optical sensors selected in Phase I already showed better stability than COTS sensors, there is still significant room for improvement. In Phase II we will perform sensor material optimization, and evaluate the sensor for stability under stress conditions for extended periods, and will optimize humidity sensors. The first demonstration unit of the electronic device will be designed, fabricated, and validated, incorporating the novel digital chip for processing the luminescent signal. Extended validation and comparison with COTS sensor devices will be conducted in the laboratory under a realistic range of environmental conditions and finally in selected field studies, in collaboration with our commercialization partner. Humidity measurement finds broad use in many industries, such as in process controls, food storage and refrigeration, quality control, homebuilding, heating, ventilation, and air conditioning, medical, healthcare, and automotive fields. The humidity monitoring market can be divided into low ppm moisture monitoring applications, mainly found in the process industry market, and ambient relative humidity monitoring applications, mainly in non-process industries where ambient humidity is monitored and controlled. IOS luminescence-based sensors will be adapted to serve both categories of markets.