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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Evaluation of the Reliability of Passive Infrared (PIR) Occupancy Sensors for Residential Indoor Lighting

Solid-state lighting (SSL) technologies have penetrated the general illumination market in recent years, largely replacing conventional technologies such as incandescent and fluorescent lighting. Most of the initial excitement about light-emitting diode (LED) sources for SSL devices focused on their energy savings potential resulting from vast improvements in source efficiency and luminous efficacy compared with conventional illumination products. More recently, the focus has shifted toward other aspects of lighting application efficiency, namely intensity effectiveness and spectral efficiency, because of the ease of controlling both the light intensity of LEDs with drive voltage and the color properties of the LED-based illuminators. To capitalize on the energy savings of increased intensity effectiveness and spectral efficiency, a lighting control system (LCS) is often used. While the current penetration of LCSs is relatively modest, it is anticipated that lighting controls (i.e., connected lighting, controls and LED and conventional lighting) could have an installed penetration as higher as 46% by the year 2035, saving an additional 1.3 quads of energy. Despite the large energy savings that can be gained from using LCSs, standard test methods for evaluating sensors employed in LCSs and reliability data of the LCSs and their components are generally lacking. The National Electrical Manufacturers Association (NEMA) developed the only standard, NEMA WD 7-2011 (R2016), to test occupancy and motion sensor performance (herein referred to as “the NEMA protocol”). In a previous U.S. Department of Energy (DOE) effort, some concerns of the NEMA protocol were identified (e.g., strict height and weight limits on test subjects, large amounts of manual effort, sometimes inconsistent repeatability). During the current work, a consistent detection length test (DLT) and a Robotic Sensor Evaluation System (RoboSES) were developed to alleviate some of these concerns. RoboSES acts as a human surrogate by using thermal pads on a mannequin and a remote-controlled mobile base to test a sensor’s field of view (FOV). This report builds on the earlier DOE efforts to understand sensor technologies used in LCSs for general illumination. Specifically, this report describes the optimization of RoboSES, characterizes and establishes test methods to assess the reliability of multiple passive infrared (PIR) sensors, and reports the findings of robustness and reliability testing on two commercial PIR sensors intended for residential applications. The information presented in this report is gained from up to 4,000 hours (hrs) of accelerated stress tests (ASTs).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

Materials Data on Ca(PIr)2 by Materials Project

Ca(IrP)2 crystallizes in the trigonal P3_221 space group. The structure is three-dimensional. Ca is bonded in a 11-coordinate geometry to five Ir and six equivalent P atoms. There are a spread of Ca–Ir bond distances ranging from 3.13–3.32 Å. There are a spread of Ca–P bond distances ranging from 3.02–3.17 Å. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 12-coordinate geometry to three equivalent Ca and four equivalent P atoms. There are two shorter (2.35 Å) and two longer (2.37 Å) Ir–P bond lengths. In the second Ir site, Ir is bonded in a 6-coordinate geometry to two equivalent Ca and four equivalent P atoms. There are two shorter (2.25 Å) and two longer (2.32 Å) Ir–P bond lengths. P is bonded to three equivalent Ca and four Ir atoms to form a mixture of distorted face, edge, and corner-sharing PCa3Ir4 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(PIr)2 by Materials Project

BaIr2P2 is Parent of FeAs superconductors-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba is bonded in a body-centered cubic geometry to eight equivalent P atoms. All Ba–P bond lengths are 3.40 Å. Ir is bonded to four equivalent P atoms to form a mixture of distorted edge and corner-sharing IrP4 tetrahedra. All Ir–P bond lengths are 2.38 Å. P is bonded in a 8-coordinate geometry to four equivalent Ba and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu(PIr)2 by Materials Project

Eu(IrP)2 crystallizes in the trigonal P3_221 space group. The structure is three-dimensional. Eu is bonded in a 11-coordinate geometry to five Ir and six equivalent P atoms. There are a spread of Eu–Ir bond distances ranging from 3.18–3.35 Å. There are a spread of Eu–P bond distances ranging from 3.06–3.18 Å. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded in a 12-coordinate geometry to three equivalent Eu and four equivalent P atoms. There are two shorter (2.35 Å) and two longer (2.40 Å) Ir–P bond lengths. In the second Ir site, Ir is bonded in a 6-coordinate geometry to two equivalent Eu and four equivalent P atoms. There are two shorter (2.27 Å) and two longer (2.33 Å) Ir–P bond lengths. P is bonded to three equivalent Eu and four Ir atoms to form a mixture of distorted face, edge, and corner-sharing PEu3Ir4 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(PIr)2 by Materials Project

SmIr2P2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight Ir and eight P atoms. There are four shorter (3.19 Å) and four longer (3.24 Å) Sm–Ir bond lengths. There are four shorter (3.12 Å) and four longer (3.15 Å) Sm–P bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded to four equivalent Sm and four equivalent P atoms to form a mixture of distorted edge and face-sharing IrSm4P4 cuboctahedra. All Ir–P bond lengths are 2.48 Å. In the second Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Sm and five P atoms. There are four shorter (2.35 Å) and one longer (2.37 Å) Ir–P bond lengths. There are two inequivalent P sites. In the first P site, P is bonded in a 8-coordinate geometry to four equivalent Sm and four equivalent Ir atoms. In the second P site, P is bonded in a 9-coordinate geometry to four equivalent Sm and five Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce(PIr)2 by Materials Project

CeIr2P2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Ce is bonded in a 12-coordinate geometry to eight Ir and eight P atoms. There are four shorter (3.19 Å) and four longer (3.23 Å) Ce–Ir bond lengths. There are four shorter (3.12 Å) and four longer (3.15 Å) Ce–P bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded to four equivalent Ce and four equivalent P atoms to form a mixture of distorted edge and face-sharing IrCe4P4 cuboctahedra. All Ir–P bond lengths are 2.48 Å. In the second Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Ce and five P atoms. There are four shorter (2.35 Å) and one longer (2.36 Å) Ir–P bond lengths. There are two inequivalent P sites. In the first P site, P is bonded in a 8-coordinate geometry to four equivalent Ce and four equivalent Ir atoms. In the second P site, P is bonded in a 9-coordinate geometry to four equivalent Ce and five Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(PIr)2 by Materials Project

K(IrP)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. K is bonded in a body-centered cubic geometry to eight equivalent P atoms. All K–P bond lengths are 3.44 Å. Ir is bonded to four equivalent P atoms to form a mixture of distorted corner and edge-sharing IrP4 tetrahedra. All Ir–P bond lengths are 2.37 Å. P is bonded in a 8-coordinate geometry to four equivalent K and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs(PIr)2 by Materials Project

Cs(IrP)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cs is bonded in a body-centered cubic geometry to eight equivalent P atoms. All Cs–P bond lengths are 3.67 Å. Ir is bonded to four equivalent P atoms to form a mixture of distorted corner and edge-sharing IrP4 tetrahedra. All Ir–P bond lengths are 2.36 Å. P is bonded in a 8-coordinate geometry to four equivalent Cs and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PIrS by Materials Project

IrPS crystallizes in the cubic P2_13 space group. The structure is three-dimensional. Ir5+ is bonded to three equivalent P3- and three equivalent S2- atoms to form IrP3S3 octahedra that share corners with twelve equivalent IrP3S3 octahedra, corners with three equivalent PIr3S tetrahedra, and corners with three equivalent SPIr3 tetrahedra. The corner-sharing octahedra tilt angles range from 65–66°. All Ir–P bond lengths are 2.36 Å. All Ir–S bond lengths are 2.42 Å. P3- is bonded to three equivalent Ir5+ and one S2- atom to form distorted PIr3S tetrahedra that share corners with three equivalent IrP3S3 octahedra, corners with six equivalent PIr3S tetrahedra, and corners with nine equivalent SPIr3 tetrahedra. The corner-sharing octahedral tilt angles are 76°. The P–S bond length is 2.19 Å. S2- is bonded to three equivalent Ir5+ and one P3- atom to form SPIr3 tetrahedra that share corners with three equivalent IrP3S3 octahedra, corners with six equivalent SPIr3 tetrahedra, and corners with nine equivalent PIr3S tetrahedra. The corner-sharing octahedral tilt angles are 77°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb(PIr)2 by Materials Project

Rb(IrP)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Rb is bonded in a body-centered cubic geometry to eight equivalent P atoms. All Rb–P bond lengths are 3.56 Å. Ir is bonded to four equivalent P atoms to form a mixture of distorted edge and corner-sharing IrP4 tetrahedra. All Ir–P bond lengths are 2.36 Å. P is bonded in a 8-coordinate geometry to four equivalent Rb and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Highly Insulated Wall Systems with Exterior Insulation of Polyisocyanurate under Different Facer Materials: Material Characterization and Long-Term Hygrothermal Performance Assessment

The application of exterior insulation in both new construction and retrofits is a common practice to enhance the energy efficiency of buildings. In addition to increased thermal performance, the rigid insulation can serve to keep the sheathing board warm and serve as a water-resistive barrier to keep moisture-related problems due to condensation and wind-driven rain. Polyisocyanurate (PIR) rigid boards have a higher thermal resistance in comparison to other commonly used exterior insulation boards. However, because of its perceived lower permeance, its use as exterior insulation is not very common. In this study, the hygrothermal property of PIR boards with different facer types and thicknesses is characterized. The material data obtained through experimental test and extrapolation is used in a long term hygrothermal performance assessment of a wood frame wall with PIR boards as exterior insulation. Results show that PIR with no facer has the smallest accumulated moisture on the sheathing board in comparison to other insulation boards. Walls with a bigger thickness of exterior insulation perform better when no vapor barrier is used. The PIR exterior insulation supports the moisture control strategy well in colder climates in perfect wall scenarios, where there is no air leakage and moisture intrusion. In cases where there is trapped moisture, the sheathing board has a higher moisture content with PIR boards with both aluminum or fiberglass type facers. An innovative facer material development for PIR boards can help efforts targeting improved energy-efficient and durable wall systems.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Design and Fabrication of Polyisocyanurate Foams toward Significantly Enhanced Thermal Resistivity

Developing high-performance thermal insulation is vital for addressing the ongoing global demand for reduced energy costs. Polyisocyanurate (PIR) foams are commonly used in residential and commercial buildings and in various industrial applications owing to their relatively high thermal insulation properties and fire resistivity. Here, this study aims to further improve the thermal resistivity of PIR foams by (1) incorporating low thermal conductivity blowing agents; (2) tailoring the anisotropy of their cells; (3) tuning polymeric isocyanate quantities; and (4) incorporating a facer barrier, while using steps that easily integrate into current manufacturing processes for PIR foams. The resulting PIR foams exhibit a significant enhancement in thermal resistivity, achieving initial values as high as 8.3 h·ft 2 ·°F/Btu/in., commonly abbreviated as R-8.3/in., which is a 20% improvement compared with that of commercially used PIR foams that achieve approximately R-7/in. The detailed analysis of thermal conductivity measurements, mechanical testing, and morphological characterization elucidates the structure–property relationships. The developed high-performance PIR foams provide a critical pillar for next-generation high-performance insulation, offering promising thermal insulation for buildings and many other applications that have a significant effect on global energy costs.

Anisotropic pores↗
DOE OSTI2020

Using an Absolute Cavity Pyrgeometer to Validate the Calibration of a Secondary Standard Pyrgeometer Outdoors, Independent from the Reference Value of the Atmospheric Longwave Irradiance

Accurate measurements of broadband outdoor longwave irradiance are important for renewable energy applications and the study of the atmosphere and climate change. A unique method of pyrgeometer calibration has been developed to improve the measurement uncertainty [1]. The results of this method yielded irradiance values within ±3 W/m 2 of those traceable to the World InfraRed Standard Group (WISG). This article describes a technique for validating this pyrgeometer calibration method using two Absolute Cavity Pyrgeometers (ACPs). The ACPs and pyrgeometer model PIR were deployed outdoors and the irradiance measured by the PIR was compared against the average irradiance measured by the two ACPs. The irradiance measured by the PIR was calculated using two equations, NREL equation and the Physikalisch Meteorologisches Observatorium Davos (PMOD) equation. The uncertainty with 95% confidence level ( U 95 ) of the irradiance measured by the PIR using NREL equation equaled ±3.51 W/m 2 with respect to SI and using PMOD equation U 95 equaled ±2.99 W/m 2 with respect to SI. These results suggest that the PIR calibration method might be useful in addressing the international need for a secondary standard pyrgeometer traceable to SI.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Using an Absolute Cavity Pyrgeometer to Calibrate Pyrgeometers Outdoors with Respect to the International System of Units

Accurate measurement of the atmospheric longwave irradiance is important for renewable energy and atmospheric science applications. Pyrgeometers are deployed outdoors all over the world to measure the atmospheric longwave irradiance and presently are calibrated with traceability to the interim standards for atmospheric longwave radiation measurement, the standards are based on four pyrgeometers and their average irradiance is the World InfraRed Standard Group (WISG) which is developed and maintained by The Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC). Since 2013 the InfraRed Integrating Sphere (IRIS) developed by PMOD/WRC and the Absolute Cavity Pyrgeometer (ACP) developed by the National Renewable Energy Laboratory (NREL) have been compared outdoors six times at different locations and the difference between the measured atmospheric longwave irradiance by ACP and IRIS was less than 2 W/m2 with traceability to the International System of Units (SI). During the six comparisons the irradiance measured by the interim WISG was 5 W/m2 lower than the irradiance measured by the average irradiance measured by the ACP and IRIS [1]. Based on this discrepancy, the World Meteorological Organization's Commission for Instruments and Methods of Observation (CIMO) recommended that the interim WISG should be adjusted to be traceable to SI units [2]. In anticipation of CIMO's expert team agreement on establishing the world reference using the average irradiance measured by ACP and IRIS in this article we describe a procedure to calibrate pyrgeometers with traceability to SI. One Absolute Cavity Pyrgeometer (ACP95F3) was used to calibrate four pyrgeometers traceable to SI units. Three Eppley PIRs and one Kipp&Zonen CG4 were originally calibrated with traceability to the interim WISG. Using the described procedure below, the responsivity of each pyrgeometer was then adjusted to match the irradiance measured by ACP. Outdoor data was collected during one clear sky nights monitored by the output thermopile voltage of ACP95F3. The irradiance measured by the PIRs was calculated using NREL equation and the CG4 using NREL equation and PMOD/WRC equation. Using the NREL equation, the calculated uncertainty (U_95) of the PIRs varied from 2.43 W/m2 to 2.67 W/m2, and for the CG4 using the NREL equation U_95 equals 1.97 W/m2, and using the PMOD equation U_95 equals 2.88 W/m2 with respect to SI.

International System of Units↗
DOE OSTI2021

Using an Absolute Cavity Pyrgeometer to Validate the Calibration of a Transfer Standard Pyrgeometer Outdoors, Independent from the Reference Value of the Atmospheric Longwave Irradiance

A unique method of pyrgeometer calibration has been developed to improve the measurement uncertainty [1]. The results of this method yielded irradiance values within ±3 W/m2 of those traceable to the World InfraRed Standard Group (WISG). The ACPs and pyrgeometer model PIR were deployed outdoors, and the irradiance measured by the PIR was compared against the irradiance measured by ACP95F3. Based on the results it is possible to achieve an uncertainty of ± 3.51 W/m2. These results suggest that the PIR calibration method might be useful in addressing the international need for a secondary standard pyrgeometer traceable to SI.

absolute cavity pyrgeometer↗
DOE OSTI2023

Using an Absolute Cavity Pyrgeometer to Calibrate Pyrgeometers Outdoors with Respect to the International System of Units

Accurate measurement of the atmospheric longwave irradiance is important for renewable energy and atmospheric science applications. Pyrgeometers are deployed outdoors all over the world to measure the atmospheric longwave irradiance and presently are calibrated with traceability to the interim standards for atmospheric longwave radiation measurement, the standards are based on four pyrgeometers and their average irradiance is the World InfraRed Standard Group (WISG) which is developed and maintained by The Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC). Since 2013 the InfraRed Integrating Sphere (IRIS) developed by PMOD/WRC and the Absolute Cavity Pyrgeometer (ACP) developed by the National Renewable Energy Laboratory (NREL) have been compared outdoors six times at different locations and the difference between the measured atmospheric longwave irradiance by ACP and IRIS was less than 2 w/m2 with traceability to the International System of Units (SI). During the six comparisons the irradiance measured by the interim WISG was 5 w/m2 lower than the irradiance measured by the average irradiance measured by the ACP and IRIS [1]. Based on this discrepancy, the World Meteorological Organization's Commission for Instruments and Methods of Observation (CIMO) recommended that the interim WISG should be adjusted to be traceable to SI units [2]. In anticipation of CIMO's expert team agreement on establishing the world reference using the average irradiance measured by ACP and IRIS in this article we describe a procedure to calibrate pyrgeometers with traceability to SI. One Absolute Cavity Pyrgeometer (ACP95F3) was used to calibrate four pyrgeometers traceable to SI units. Three Eppley PIRs and one Kipp&Zonen CG4 were originally calibrated with traceability to the interim WISG. Using the described procedure below, the responsivity of each pyrgeometer was then adjusted to match the irradiance measured by ACP. Outdoor data was collected during one clear sky night monitored by the output thermopile voltage of ACP95F3. The irradiance measured by the PIRs and CG4 was calculated using NREL equation. The calculated uncertainty (U95) of the PIRs varied from 2.43 w/m2 to 2.67 w/m2 , and for the CG4 equals 1.97 w/m2 with respect to SI.

absolute cavity pyrgeometer↗