The Design and Development of a Capture Efficiency Test Facility By Using Tracer Gas Monitoring For Performance Testing of Kitchen Ventilation Systems

Effective kitchen ventilation systems are critical for removing hazardous pollutants generated during cooking to maintain acceptable levels of indoor air quality. Current indoor air quality standards specify air flow and sound ratings as the only metrics to analyze the performance of kitchen ventilation. Lawrence Berkeley National Laboratory has been working alongside ASTM to develop a test standard for analyzing the fraction of cooking pollutants removed by kitchen range hoods. RELLIS Energy Efficiency Laboratory (REEL) was given the opportunity to design, develop, and construct a capture efficiency test facility using tracer gas monitoring to analyze the performance of kitchen ventilation systems. REEL established seven sub-components of the testing facility based on the requirements outlined in the test standard developed by LBNL. The 4.34 m x 3.93 m x 3.05 m testing chamber was sized to best represent a residential kitchen, which can accommodate range hood flow rates up to 200 L/s. All components and necessary equipment and instrumentation were designed and selected to conform to the dimensional, measurement, and accuracy requirements outlined in the test standard. Testing procedures were developed and preliminary data for 5 kitchen range hoods were taken to qualify the room and to analyze the effects of range hood air flow, mounting height, and cooking surface temperature on capture efficiency. Air flow rates 150 cfm yielded capture efficiencies between 86-92%. Average capture efficiencies were 67.7% and 77.8% for mounting heights of 30” and 21” for flow rates < 150 cfm, respectively, while at air flow rates > 190 cfm, capture efficiencies were measured to be 88.2% (30”) and 90.3% (21”). At air flow rates < 130 cfm capture efficiencies were 66.4% and 55.6% for surface temperatures of 150 0C and 200 0C, respectively. At air flow rates > 160 cfm, capture efficiencies were measured to be 79.9% and 74.3%. It was found that capture efficiency increased with increasing air flow rates, and decreasing mounting heights (closer to cooking surface) and surface temperatures. Large differences in measured capture efficiencies at flow rates < 150 cfm suggests that cooking and ventilation parameters are more impactful at lower operating speeds

A Framework for Automatic Behavior Generation in Multi-Function Swarms

Multi-function swarms are swarms that solve multiple tasks at once. For example, a quadcopter swarm could be tasked with exploring an area of interest while simultaneously functioning as ad-hoc relays. With this type of multi-function comes the challenge of handling potentially conflicting requirements simultaneously. Using the Quality-Diversity algorithm MAP-elites in combination with a suitable controller structure, a framework for automatic behavior generation in multi-function swarms is proposed. The framework is tested on a scenario with three simultaneous tasks: exploration, communication network creation and geolocation of RF emitters. A repertoire is evolved, consisting of a wide range of controllers, or behavior primitives, with different characteristics and trade-offs in the different tasks. This repertoire would enable the swarm to transition between behavior trade-offs online, according to the situational requirements. Furthermore, the effect of noise on the behavior characteristics in MAP-elites is investigated. A moderate number of re-evaluations is found to increase the robustness while keeping the computational requirements relatively low. A few selected controllers are examined, and the dynamics of transitioning between these controllers are explored. Finally, the study develops a methodology for analyzing the makeup of the resulting controllers. This is done through a parameter variation study where the importance of individual inputs to the swarm controllers is assessed and analyzed

The Design and Development of a Capture Efficiency Test Facility By Using Tracer Gas Monitoring For Performance Testing of Kitchen Ventilation Systems

Effective kitchen ventilation systems are critical for removing hazardous pollutants generated during cooking to maintain acceptable levels of indoor air quality. Current indoor air quality standards specify air flow and sound ratings as the only metrics to analyze the performance of kitchen ventilation. Lawrence Berkeley National Laboratory has been working alongside ASTM to develop a test standard for analyzing the fraction of cooking pollutants removed by kitchen range hoods. RELLIS Energy Efficiency Laboratory (REEL) was given the opportunity to design, develop, and construct a capture efficiency test facility using tracer gas monitoring to analyze the performance of kitchen ventilation systems. REEL established seven sub-components of the testing facility based on the requirements outlined in the test standard developed by LBNL. The 4.34 m x 3.93 m x 3.05 m testing chamber was sized to best represent a residential kitchen, which can accommodate range hood flow rates up to 200 L/s. All components and necessary equipment and instrumentation were designed and selected to conform to the dimensional, measurement, and accuracy requirements outlined in the test standard. Testing procedures were developed and preliminary data for 5 kitchen range hoods were taken to qualify the room and to analyze the effects of range hood air flow, mounting height, and cooking surface temperature on capture efficiency. Air flow rates 150 cfm yielded capture efficiencies between 86-92%. Average capture efficiencies were 67.7% and 77.8% for mounting heights of 30” and 21” for flow rates < 150 cfm, respectively, while at air flow rates > 190 cfm, capture efficiencies were measured to be 88.2% (30”) and 90.3% (21”). At air flow rates < 130 cfm capture efficiencies were 66.4% and 55.6% for surface temperatures of 150 0C and 200 0C, respectively. At air flow rates > 160 cfm, capture efficiencies were measured to be 79.9% and 74.3%. It was found that capture efficiency increased with increasing air flow rates, and decreasing mounting heights (closer to cooking surface) and surface temperatures. Large differences in measured capture efficiencies at flow rates < 150 cfm suggests that cooking and ventilation parameters are more impactful at lower operating speeds

DEVELOPMENT OF INSTRUMENTATION AND CONTROL SYSTEMS FOR AN INTEGRAL LARGE SCALE PRESSURIZED WATER REACTOR

Small and large scale integral light water reactors are being developed to supply electrical power and to meet the needs of process heat, primarily for water desalination. This dissertation research focuses on the instrumentation and control of a large integral inherently safe light water reactor (designated as I2S-LWR) which is being designed as part of a grant by the U.S. Department of Energy Integrated Research Project (IRP). This 969 MWe integral pressurized water reactor (PWR) incorporates as many passive safety features as possible while maintaining competitive costs with current light water reactors. In support of this work, the University of Tennessee has been engaged in research to solve the instrumentation and control challenges posed by such a reactor design. This dissertation is a contribution to this effort. The objectives of this dissertation are to establish the feasibility and conceptual development of instrumentation strategies and control approaches for the I2S-LWR, with consideration to the state of the art of the field. The objectives of this work are accomplished by the completion of the following tasks: Assessment of instrumentation needs and technology gaps associated with the instrumentation of the I2S-LWR for process monitoring and control purposes. Development of dynamic models of a large integral PWR core, micro-channel heat exchangers (MCHX) that are contained within the reactor pressure vessel, and steam flashing drums located external to the containment building. Development and demonstration of control strategies for reactor power regulation, steam flashing drum pressure regulation, and flashing drum water level regulation for steady state and load-following conditions. Simulation, detection, and diagnosis of process anomalies in the I2S-LWR model. This dissertation is innovative and significant in that it reports the first instrumentation and control study of nuclear steam supply by integral pressurized water reactor coupled to an isenthalpic expansion vessel for steam generation. Further, this dissertation addresses the instrumentation and control challenges associated with integral reactors, as well as improvements to inherent safety possible in the instrumentation and control design of integral reactors. The results of analysis and simulation demonstrate the successful development of dynamic modeling, control strategies, and instrumentation for a large integral PWR

Airborne laser sensors and integrated systems

The underlying principles and technologies enabling the design and operation of airborne laser sensors are introduced and a detailed review of state-of-the-art avionic systems for civil and military applications is presented. Airborne lasers including Light Detection and Ranging (LIDAR), Laser Range Finders (LRF), and Laser Weapon Systems (LWS) are extensively used today and new promising technologies are being explored. Most laser systems are active devices that operate in a manner very similar to microwave radars but at much higher frequencies (e.g., LIDAR and LRF). Other devices (e.g., laser target designators and beam-riders) are used to precisely direct Laser Guided Weapons (LGW) against ground targets. The integration of both functions is often encountered in modern military avionics navigation-attack systems. The beneficial effects of airborne lasers including the use of smaller components and remarkable angular resolution have resulted in a host of manned and unmanned aircraft applications. On the other hand, laser sensors performance are much more sensitive to the vagaries of the atmosphere and are thus generally restricted to shorter ranges than microwave systems. Hence it is of paramount importance to analyse the performance of laser sensors and systems in various weather and environmental conditions. Additionally, it is important to define airborne laser safety criteria, since several systems currently in service operate in the near infrared with considerable risk for the naked human eye. Therefore, appropriate methods for predicting and evaluating the performance of infrared laser sensors/systems are presented, taking into account laser safety issues. For aircraft experimental activities with laser systems, it is essential to define test requirements taking into account the specific conditions for operational employment of the systems in the intended scenarios and to verify the performance in realistic environments at the test ranges. To support the development of such requirements, useful guidelines are provided for test and evaluation of airborne laser systems including laboratory, ground and flight test activities

A Framework for Automatic Behavior Generation in Multi-Function Swarms

17 USC 105 interim-entered record; under review.Multi-function swarms are swarms that solve multiple tasks at once. For example, a quadcopter swarm could be tasked with exploring an area of interest while simultaneously functioning as ad-hoc relays. With this type of multi-function comes the challenge of handling potentially conflicting requirements simultaneously. Using the Quality-Diversity algorithm MAP-elites in combination with a suitable controller structure, a framework for automatic behavior generation in multi-function swarms is proposed. The framework is tested on a scenario with three simultaneous tasks: exploration, communication network creation and geolocation of Radio Frequency (RF) emitters. A repertoire is evolved, consisting of a wide range of controllers, or behavior primitives, with different characteristics and trade-offs in the different tasks. This repertoire enables the swarm to online transition between behaviors featuring different trade-offs of applications depending on the situational requirements. Furthermore, the effect of noise on the behavior characteristics in MAP-elites is investigated. A moderate number of re-evaluations is found to increase the robustness while keeping the computational requirements relatively low. A few selected controllers are examined, and the dynamics of transitioning between these controllers are explored. Finally, the study investigates the importance of individual sensor or controller inputs. This is done through ablation, where individual inputs are disabled and their impact on the performance of the swarm controllers is assessed and analyzed