Heather Dillon

A Fundamental Equation for Calculation of the Thermodynamic Properties of Ethanol

A formulation for the thermodynamic properties of ethanol (C2H5OH) in the liquid, vapor, and saturation states is presented. The formulation is valid for single-phase and saturation states from 250 to 650 K at pressures up to 280 MPa. The formulation includes a fundamental equation and ancillary functions for the estimation of saturation properties. The experimental data used to determine the fundamental equation include pressure-density-temperature, ideal gas heat capacity, speed of sound, and vapor pressure. Saturation values computed from the ancillary functions were used to ensure thermodynamic consistency at the vapor-liquid phase boundary. Comparisons between experimental data and values computed using the fundamental equation are given to verify the uncertainties in the calculated properties. The formulation presented may be used to compute densities to within ±0.2%, heat capacities to within ±3%, and speed of sound to within ±1%. Saturation values of the vapor pressure and saturation densities are represented to within ±0.5%, except near the critical point.

Optimizing the Advanced Ceramic Material for Diesel Particulate Filter Applications

This paper describes the application of pore-scale filtration simulations to the ‘Advanced Ceramic Material’ (ACM) developed by Dow Automotive for use in advanced diesel particulate filters. The application required the generation of a three dimensional substrate geometry to provide the boundary conditions for the flow model. An innovative stochastic modeling technique was applied matching chord length distribution and the porosity profile of the material. Additional experimental validation was provided by the single channel experimental apparatus. Results show that the stochastic reconstruction techniques provide flexibility and appropriate accuracy for the modeling efforts. Early optimization efforts imply that needle length may provide a mechanism for adjusting performance of the ACM for DPF applications. New techniques have been developed to visualize soot deposition in both traditional and new DPF substrate materials. Loading experiments have been conducted on a variety of single channel DPF substrates to develop a deeper understanding of soot penetration, soot deposition characteristics, and to confirm modeling results.

The Effect of Spatially Correlated Roughness and Boundary Conditions on the Conduction of Heat Through a Slab

The nominally one-dimensional conduction of heat through a slab becomes two dimensional when one of the surfaces is rough or when the boundary conditions are spatially nonuniform. This paper develops the stochastic equations for a slab whose surface roughness or convective boundary condition is spatially correlated with correlation lengths ranging from 0 (white noise) to a length long in comparison to the slab thickness. The effect is described in terms of the standard deviation and the resulting spatial correlation of the heat flux as a function of depth into the slab. In contrast to the expectation that the effect is monotonic with respect to the correlation length, it is shown that the effect is maximized at an intermediate correlation length. It is also shown that roughness or a random convective heat transfer coefficient have essentially the same effects on the conducted heat, but that the combination results in a much deeper penetration than does each effect individually. In contrast to the usual methods of solving stochastic problems, both the case of a rough edge and a smooth edge with stochastic convective heat transfer coefficients can only be treated with reasonable computational expense by using direct Monte Carlo simulations.

Independent Analysis of Real-Time, Measured Performance Data From Microcogenerative Fuel Cell Systems Installed in Buildings

Pacific Northwest National Laboratory (PNNL) is working with industry to independently monitor up to 15 distinct 5 kW-electric (kWe) combined heat and power (CHP) high temperature (HT) proton exchange membrane (PEM) fuel cell systems (FCSs) installed in light commercial buildings. This research paper discusses an evaluation of the first six months of measured performance data acquired at a 1 s sampling rate from real-time monitoring equipment attached to the FCSs at building sites. Engineering performance parameters are independently evaluated. Based on an analysis of the first few months of measured operating data, FCS performance is consistent with manufacturer-stated performance. Initial data indicate that the FCSs have relatively stable performance and a long-term average production of about 4.57 kWe of power. This value is consistent with, but slightly below, the manufacturers stated rated electric power output of 5 kWe. The measured system net electric efficiency has averaged 33.7%, based on the higher heating value (HHV) of natural gas fuel. This value, also, is consistent with, but slightly below, the manufacturers stated rated electric efficiency of 36%. The FCSs provide low-grade hot water to the building at a measured average temperature of about 48.4 °C, lower than the manufacturers stated maximum hot water delivery temperature of 65 °C. The uptime of the systems is also evaluated. System availability can be defined as the quotient of total operating time compared to time since commissioning. The average values for system availability vary between 96.1 and 97.3%, depending on the FCS evaluated in the field. Performance at rated value for electrical efficiency (PRVeff) can be defined as the quotient of the system time operating at or above the rated electric efficiency and the time since commissioning. The PRVeff varies between 5.6% and 31.6%, depending on the FCS field unit evaluated. Performance at rated value for electrical power (PRVp) can be defined as the quotient of the system time operating at or above the rated electric power and the time since commissioning. PRVp varies between 6.5% and 16.2%. Performance at rated value for electrical efficiency and power (PRVt) can be defined as the quotient of the system time operating at or above both the rated electric efficiency and the electric power output compared to the time since commissioning. PRVt varies between 0.2% and 1.4%. Optimization to determine the manufacturer rating required to achieve PRVt greater than 80% has been performed based on the collected data. For example, for FCS Unit 130 to achieve a PRVt of 95%, it would have to be down-rated to an electrical power output of 3.2 kWe and an electrical efficiency of 29%. The use of PRV as an assessment metric for FCSs has been developed and reported for the first time in this paper. For FCS Unit 130, a maximum decline in electric power output of approximately 18% was observed over a 500 h period in Jan. 2012.

Independent Evaluation of Measured Performance Data for Cutting-Edge Combined Heat and Power Fuel Cell Systems Installed in Buildings

Pacific Northwest National Laboratory (PNNL) is working with industry to independently monitor up to fifteen distinct 5 kilowatt-electric (kWe) combined heat and power (CHP) high temperature (HT) proton exchange membrane (PEM) fuel cell systems (FCSs) installed in light commercial buildings. This research paper discusses an evaluation of the first six months of measured performance data acquired at a one-second sampling rate from real-time monitoring equipment attached to the FCSs at building sites. Engineering performance parameters are independently evaluated.Based on an analysis of the first few months of measured operating data, FCS performance is consistent with manufacturer-stated performance. Initial data indicate that the FCSs have relatively stable performance and a long term average production of about 4.57 kWe of power. This value is consistent with, but slightly below, the manufacturer’s stated rated electric power output of 5 kWe. The measured system net electric efficiency has averaged 33.7%, based on the higher heating value (HHV) of natural gas fuel. This value, also, is consistent with, but slightly below, the manufacturer’s stated rated electric efficiency of 36%. The FCSs provide low-grade hot water to the building at a measured average temperature of about 48.4°C, lower than the manufacturer’s stated maximum hot water delivery temperature of 65°C.The uptime of the systems is also evaluated. System availability can be defined as the quotient of total operating time compared to time since commissioning. The average values for system availability vary between 96.1 and 97.3%, depending on the FCS evaluated in the field. Performance at Rated Value for electrical efficiency (PRVeff) can be defined as the quotient of the system time operating at or above the rated electric efficiency and the time since commissioning. The PRVeff varies between 5.6% and 31.6%, depending on the FCS field unit evaluated. Performance at Rated Value for electrical power (PRVp) can be defined as the quotient of the system time operating at or above the rated electric power and the time since commissioning. PRVp varies between 6.5% and 16.2%. Performance at Rated Value for electrical efficiency and power (PRVt) can be defined as the quotient of the system time operating at or above both the rated electric efficiency and the electric power output compared to the time since commissioning. PRVt varies between 0.2% and 1.4%. Optimization to determine the manufacturer rating required to achieve PRVt greater than 80% has been performed based on the collected data. For example, for FCS unit 130 to achieve a PRVt of 95%, it would have to be down-rated to an electrical power output of 3.2 kWe and an electrical efficiency of 29%.The use of PRV as an assessment metric for FCSs has been developed and reported for the first time in this paper.For FCS Unit 130, a 20% decline in electric power output was observed from approximately 5 kWe to 4 kWe over a 1,500 hour period between Dec. 14th 2011 and Feb. 14th 2012.Copyright

Design and build of an electrical generator and load control system for a novel small-scale hybrid solar thermal collector

The primary goal of this research was to design the electrical generation and control system for a small-scale solar-thermal collector, which was optimized for the Pacific Northwest. The project team collected data on the existing solar-thermal system and worked to design a power conversion system to generate electricity. Design and implementation of the generator, prime mover, and electric load controller are discussed in the paper.

Building Inclusive Undergraduate Teams

This paper describes a research project to encourage and enhance formation of undergraduate project teams with a focus on inclusivity. The project was developed by a team of undergraduate students working with a pair of engineering faculty. A survey including questions about team study groups was prepared and used to gather data about how engineering student teams are formed and how students perceive teams at different points as they progress through the curriculum. Interviews with junior/senior level students were filmed and the footage was used to build a composite video to serve as motivation to first and second year students. The video was presented in a second year dynamics class and the students were surveyed to understand the effectiveness of the intervention.The survey results indicate that nearly half of all junior/senior engineering students feel ethically charged to include other students in a study group, while only 32% of second year students feel ethically charged. This research is part of a larger effort to develop methods for merging engineering ethics and professionalism in the mechanical engineering curriculum.Copyright

Design of a Power Waveform Capture Platform for Plug Load Monitoring

Plug loads in consumer electronic products consume large quantities of energy, often without the knowledge of the user. To facilitate the development of smart plug strips and new building control systems, an open-source power waveform capture platform has been designed and tested. The system was developed to accurately and safely record the voltage and current waveforms for any plug load such as consumer electronic and electrical systems. The device incorporates a commercially available hardware platform that has been reprogrammed to record the voltage and current waveforms and transfer them in real-time to a computer for storage and further processing. The system samples the voltage and current waveforms with a sampling rate of 2048 Hz, and this detailed data can be used to identify the types of waveforms that are associated with various devices, as well as measure any power parameter of interest such as real power, energy, RMS volts, RMS current, power factor, frequency, etc. The system has been tested with several known electrical loads and has been found to perform well. The paper describes the hardware and software, the test setup, and the test results. Since the hardware is inexpensive (about

Quantitative Study of Photovoltaic Arrays in the Pacific Northwest: Analyzing a Photovoltaic System in Portland Oregon

250) and the software is available for free from the authors, this system can be used by almost anyone to perform detailed studies of the power characteristics of electrical and electronic devices.Copyright

Robust Data Acquisition for Building Lighting Systems

This paper describes a quantitative study conducted on the performance of the photovoltaic (PV) system at the University of Portland in Oregon. The objective of the study was to compare the performance to other PV systems in the Pacific Northwest. Data collected over a span of two years was used to determine the maximum and minimum energy production days of the year, to generate average monthly performance and annual energy plots, to observe correlation between outside temperature and the photovoltaic system performance, and to compare actual performance of the system to the expected performance. The greatest energy production day was found to be July 11, 2013 with total energy production of about 35 kWh. The minimum energy production day was found to be January 16, 2013 with total energy production of about 1 kWh. According to initial calculations and analysis, the actual performance of the photovoltaic system reaches an efficiency of around 12.3%. Expected system performance was listed at an estimated rating of 14.9%, indicating a slight reduction from expected performance. From the analysis conducted, the photovoltaic system has been found to be performing close to expectations. Continued analysis of the system will allow for further comparison to other PV systems in the Pacific Northwest.Copyright