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DOE OSTI2021

Remote Alaska Communities Energy Efficiency Competition: Energy Efficiency for the Gem of the Yukon (Final Report)

Over the past decade, the City of Ruby has been proactive in working to reduce cost and energy use in the community. Ruby (Tl’aa’ologhe) is a remote city in Alaska located on the south bank of the Yukon River near the Kilbuck-Kuskokwim Mountains, about 50 air miles east of Galena and 230 air miles west of Fairbanks. As of 2019, the community has a population of over 150 people and most of Ruby’s residents are Koyukon Athabascan. Ruby has a long history of promoting local efficiency and clean energy in an effort to become more sustainable. Between 2007-2010, the community hosted Alaska’s first demonstration of an in-river hydrokinetic test project, sponsored by the Yukon River Inter-Tribal Watershed Council. In 2011, a 5kW solar photo-voltaic (PV) array was installed by the Interior Regional Housing Authority. In 2012, the community had a new power plant constructed by the Alaska Energy Authority that supplies waste heat to the washeteria, clinic and public safety garage, saving the community more than 4,000 gallons of heating fuel per year. The clinic, constructed by the Tanana Chiefs Conference, is one of the most energy efficient buildings in the interior and utilizes new building efficiency standards that were passed by the tribes. It has a 5kW solar PV array that provides energy into the local electric grid and offsets approximately 20% of the annual energy use. Building on this legacy, the City of Ruby entered into Department of Energy’s (DOE’s) Remote Alaska Communities Energy Efficiency Competition (RACEE) in 2016, pledging to reduce per-capita energy use 15% by 2020. During the second phase of the competition, 13 communities including Ruby were provided funding for tailored technical assistance to measure energy use and create energy efficiency plans.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

DOE OSTI2024

A Program Design Combining Community Solar and Weatherization for Manufactured Homes in Michigan

The Michigan Department of Environment, Great Lakes, and Energy (EGLE) is interested in combining community solar with weatherization programs for manufactured homes. To collect program strategies, EGLE made a request for technical assistance from the US Department of Energy’s National Community Solar Partnership (NCSP). Lawrence Berkeley National Lab developed this study in response. It briefly reviews issues relevant to the question, attempts to lay out a methodology for more in-depth analysis, and provides some recommendations for program design and implementation. While the research is specific to Michigan, the recommendations and methodologies could serve as an example for other states and regions. The paper first provides an overview of manufactured home communities in Michigan, with a discussion of demographics and energy issues they face. It then discusses weatherization opportunities for manufactured homes, opportunities for community solar, and opportunities for combining the two. The methodology proposed is intended to help EGLE: -Identify priority locations, -Set eligibility criteria for communities and households, and -Make the most of federal and other funding sources The paper concludes with recommendations for a program that combines community solar with efficient electrification of manufactured homes to reduce the burden of the largest source of energy expenditure in Michigan, winter heating bills. Specifically, it envisions community solar subscriptions for occupants of manufactured homes that have been converted to high-efficiency cold weather heat pumps. The combination can be managed to alleviate seasonal variations in both solar and heating bills, such as through an annualized “budget billing” program.

14 SOLAR ENERGY↗

DOE OSTI2025

Performance Evaluation of Low-Cost Condensers Immersed in the Water Tank of a Heat Pump Water Heater

This paper reports the effect of low-cost immersed condensers on the performance of a heat pump water heater (HPWH) that does not require a water-circulating pump. The proposed design is based on the immersion of an L-style condenser coil through an opening in the top of the water tank. The novel design aims to eliminate the need for the water-circulating pumps, thereby substantially improving efficiency and reducing costs and maintenance of the HPWH system. Comprehensive computational fluid dynamics (CFD) simulations and experimental tests were performed, and the results showed that the CFD simulations were close to the experimental data. Further results confirm that the L-style condenser can introduce buoyancy-driven flow and eliminate temperature stratification in the studied HPWH water tank, thereby improving the heat transfer coefficient and coefficient of performance of the HPWH. The testing results further showed that the L-style condenser enabled more than 53% higher coefficient of performance and 400% higher heat transfer coefficient compared with the straight vertical condenser, and achieved much faster water heating. Furthermore, the effects of immersed condensers with different circuits on the HPWH performance were evaluated and compared. All results indicate that the current energy-saving and inexpensive HPWH technology is technically valid, and the benefits of performance improvement and low cost are attractive in future HPWH design.

Gao, Zhiming [ORNL] (ORCID:0000000271397995)↗

NASA NTRS1975

Better vacuum by removal of diffusion-pump-oil contaminants

The complex problem of why large space simulation chambers do not realize true ultimate vacuum was investigated. Some contaminating factors affecting diffusion pump performance were identified, and some advances in vacuum distillation-fractionation technology were achieved which resulted in a two-decade-or-more lower ultimate pressure. Data are presented to show the overall or individual contaminating effects of commonly used phthalate ester plasticizers of 390 to 530 molecular weight on diffusion pump performance. Methods for removing contaminants from diffusion pump silicone oil during operation and for reclaiming contaminated oil by high-vacuum molecular distillation are described. Conceptual self-cleansing designs and operating procedures are proposed for modifying large diffusion pumps into high-efficiency distillation devices. The potential exists for application of these technological advancements to other disciplines, such as medicine, biomedical materials, metallurgy, refining, and chemical (diffusion-enrichment) processing.

Buggele, A. E.↗

NASA NTRS1980

Neodymium YAG lasers. Citations from the International Aerospace Abstracts data base

Various aspects of neodymium yag lasers are discussed in approximately 267 citations. Laser materials and outputs, laser mode locking; crystal, fiber, and nonlinear optics, optical pumping communications, energy conversion efficiency, and laser applications are covered. Pulsed, continuous wave, solid state, Q switched, infrared, and dye lasers are included.

Mauk, S. C.↗

NASA NTRS1983

Laser induced asymmetry and inhomogeneous broadening of the microwave lineshape of a gas cell atomic frequency standard

The possibility of replacing the RF discharge lamp in a rubidium gas cell clock with a single mode laser diode is addressed. Since the short term stability of the rubidium frequency standard is limited by the shot noise of the photodetector, an increased signal-to-noise ratio due to more efficient laser diode optical pumping might improve the short term performance. Because the emission wavelength of the laser diode can be tuned, improved long term performance could be gained through the control of the light shift effect. However, due to the nature of the gas cell frequency standard, various physical phenomena are strongly coupled in their effect on the frequency output, and thus careful consideration must be given to any change in one parameter because of its interrelation with other parameters. Some investigations concerning the coupled effect of the optical and microwave fields in the rubidium atomic clock are reported. It is shown that this type of coupling is an important consideration for any attempt to incorporate a laser diode into a gas cell clock.

Camparo, J. C.↗

NASA NTRS1983

NASA multipurpose airborne DIAL system and measurements of ozone and aerosol profiles

The hardware, operational characteristics, data processing system, and applications of the NASA airborne differential absorption lidar (DIAL) system are described. DIAL functions by assessing the average gas concentration over a specified range interval by analyzing the difference in lidar backscatter signals for laser wavelengths tuned on and off of the molecular absorption line of a gas under investigation. The system comprises two frequency-doubled Nd:YAG lasers pumping two high conversion efficiency tunable dye lasers emitting pulses separated by 100 microsec or less. The return signals are digitized and stored on magnetic tape. The signal collector consists of photomultiplier tubes implanted in a cassegrain telescope. Flight tests of the system involved on-measurements at 285.95 nm and off-measurements at 299.40 nm, which yielded a differential cross section of 1.74 x 10 to the -16th sq cm. In situ measurements with another plane at a nominal altitude of 3.2 km for comparison purposes showed accuracy to within 10% in and above the boundary layer. The system is considered as a test apparatus for more developed versions to be flown on the Shuttle

Browell, E. V.↗

NASA NTRS1989

Theory of the optimally coupled Q-switched laser

The general equations describing Q-switched laser operation are transcendental in nature and require numerical solutions, which greatly complicates the optimization of real devices. Here, it is shown that, using the mathematical technique of Lagrange multipliers, one can derive simple analytic expressions for all of the key parameters of the optimally coupled laser, i.e., one which uses an optimum reflector to obtain maximum laser efficiency for a given pump level. These parameters can all be expressed as functions of a single dimensionless variable z, defined as the ratio of the unsaturated small-signal gain to the dissipative (nonuseful) optical loss, multiplied by a few simple constants. Laser design tradeoff studies and performance projections can be accomplished quickly with the help of several graphs and a simple hand calculator. Sample calculations for a high-gain Nd:YAG and a low-gain alexandrite laser are presented as illustrations of the technique.

Degnan, John J.↗

NASA NTRS1990

Equations For Isocaloric Fountain-Effect Pumps

Report presents equations for thermodynamical characteristics of leaky fountain-effect pumps operating at constant rates of input heating. Differ from those developed previously for fountain-effect pumps operating at constant differences of temperature, in which pressure heads and rates of flow independent of each other. Resulting equations used to calculate various measures of performance of leaky fountain-effect pump; e.g., pressure head as function of mass-flow rate, hydrothermodynamic efficiency, and transfer effectiveness (fraction of pumped mass remaining after portion evaporated to keep process at constant temperature).

Kittel, Peter↗

NASA NTRS1990

A rocket-borne He-3 refrigerator

A self-contained, recyclable He-3 refrigerator suitable for use in space has been developed. The refrigerator is compact, has no moving parts, and requires only electrical connections and thermal contact in order to operate from a 2 K cold stage. A charcoal adsorption pump is used to efficiently condense and cool the He-3. Sintered copper confines the He-3 to the evaporator in zero-gravity and, in fact, allows the refrigerator to operate upside-down in the laboratory. Mounted on a 2 K cold stage, the refrigerator provides 100 microwatts of cooling power at 346 mK, with a 7 hour hold time. On a 1.5 K cold stage, the lowest temperature achieved is 277 mK. The refrigerator has been vibration tested at 7.5 G amplitude from 30 to 400 Hz and 15 G amplitude from 400 to 2000 Hz.

Duband, L.↗

NASA NTRS1993

Design of an oxygen turbopump for use in an Advanced Expander Test Bed engine

A liquid oxygen (LOX) turbopump with a gaseous hydrogen turbine drive was designed for the Advanced Expander Test Bed (AETB), which is a technology test bed to develop future space engines. This turbopump features a single stage, full admission, high reaction turbine: a three-bladed axial flow inducer, a high efficiency single stage centrifugal pump with an integrally shrouded impeller; an interpropellant seal package with an oxygen vaporizer; and a subcritical rotor with two ball bearings for axial loads and one roller bearing for turbine radial loads. Material selections were based on compatibility with operating fluids and temperatures. The pump was designed to operate over a 20:1 power range with a maximum performance point of 283.0 GPM of liquid oxygen at a pump discharge pressure of 2198 psia, and a shaft speed of 47,914 rpm. The split expander cycle engine and the performance it requires of the LOX turbopump is discussed as well as the design of the turbopump components.

Pattison, William W.↗

NASA NTRS2003

Decoupling of Iron and Phosphate in the Global Ocean

Iron is an essential micronutrient for marine phytoplankton, limiting their growth in high nutrient, low chlorophyll regions of the ocean. I use a hierarchy of ocean circulation and biogeochemistry models to understand controls on global iron distribution. I formulate a mechanistic model of iron cycling which includes scavenging onto sinking particles and complexation with an organic ligand. The iron cycle is coupled to a phosphorus cycling model. Iron's aeolian source is prescribed. In the context of a highly idealized multi-box model scheme, the model can be brought into consistency with the relatively sparse ocean observations of iron in the oceans. This biogeochemical scheme is also implemented in a coarse resolution ocean general circulation model. This model also successfully reproduces the broad regional patterns of iron and phosphorus. In particular, the high macronutrient concentrations of the Southern Ocean result from iron limitation in the model. Due to the potential ability of iron to change the efficiency of the carbon pump in the remote Southern Ocean, I study Southern Ocean surface phosphate response to increased aeolian dust flux. My box model and GCM results suggest that a global ten fold increase in dust flux can support a phosphate drawdown of 0.25-0.5 micromolar.

GLOBAL OCEAN MODEL↗

NASA NTRS2004

Progress on Space Borne Laser Risk Reduction at Goddard Space Flight Center

At the direction of NASA Headquarters NASA Goddard Space Flight Center (GSFC) and NASA Langley Research Center (LaRC) undertook in 2002 a program in fundamental research on laser manufacturing technologies aimed at improving the performance and lifetime of lasers sent into space for remote sensing applications. The work at GSFC has concentrated on three areas: 1) development of high power 1 micron lasers, 2) lifetime and reliability testing for 808 nm pump diodes, and 3) efficient conversion of 1 micron radiation to wavelengths needed for various remote sensing tasks. After almost 2 years of development interesting results in all three areas are beginning to emerge. Some of these results will be described along with discussion of future directions.

Heaps, William S.↗

NASA NTRS2010

Free-Piston Stirling Power Conversion Unit for Fission Surface Power, Phase I Final Report

This report summarizes the design of a 12 kW dual opposed free-piston Stirling convertor and controller for potential future use in space missions. The convertor is heated via a pumped NaK loop and cooling is provided by a pumped water circuit. Convertor efficiency is projected at 27 percent (AC electrical out/heat in). The controller converts the AC electrical output to 120 Vdc and is projected at 91 percent efficiency. A mechanically simple arrangement, based on proven technology, was selected in which the piston is resonated almost entirely by the working space pressure swing, while the displacer is resonated by planar mechanical springs in the bounce space.

Wood, J. Gary↗

NASA NTRS2014

Submerged AUV Charging Station

Autonomous Underwater Vehicles (AUVs) are becoming increasingly important for military surveillance and mine detection. Most AUVs are battery powered and have limited lifetimes of a few days to a few weeks. This greatly limits the distance that AUVs can travel underwater. Using a series of submerged AUV charging stations, AUVs could travel a limited distance to the next charging station, recharge its batteries, and continue to the next charging station, thus traveling great distances in a relatively short time, similar to the Old West “Pony Express.” One solution is to use temperature differences at various depths in the ocean to produce electricity, which is then stored in a submerged battery. It is preferred to have the upper buoy submerged a reasonable distance below the surface, so as not to be seen from above and not to be inadvertently destroyed by storms or ocean going vessels. In a previous invention, a phase change material (PCM) is melted (expanded) at warm temperatures, for example, 15 °C, and frozen (contracted) at cooler temperatures, for example, 8 °C. Tubes containing the PCM, which could be paraffin such as pentadecane, would be inserted into a container filled with hydraulic oil. When the PCM is melted (expanded), it pushes the oil out into a container that is pressurized to about 3,000 psi (approx equals 20.7 MPa). When a valve is opened, the high-pressure oil passes through a hydraulic motor, which turns a generator and charges a battery. The low-pressure oil is finally reabsorbed into the PCM canister when the PCM tubes are frozen (contracted). Some of the electricity produced could be used to control an external bladder or a motor to the tether line, such that depth cycling is continued for a very long period of time. Alternatively, after the electricity is generated by the hydraulic motor, the exiting low-pressure oil from the hydraulic motor could be vented directly to an external bladder on the AUV, such that filling of the bladder causes the AUV to rise, and emptying of the bladder allows the AUV to descend. This type of direct buoyancy control is much more energy efficient than using electrical pumps in that the inefficiencies of converting thermal energy to electrical energy to mechanical energy is avoided. AUV charging stations have been developed that use electricity produced by waves on floating buoys and that use electricity from solar photovoltaics on floating buoys. This is the first device that has absolutely no floating or visible parts, and is thus impervious to storms, inadvertent ocean vessel collisions, or enemy sabotage.

Jones, Jack A.↗

NASA NTRS2014

Distributed Prognostics based on Structural Model Decomposition

Within systems health management, prognostics focuses on predicting the remaining useful life of a system. In the model-based prognostics paradigm, physics-based models are constructed that describe the operation of a system and how it fails. Such approaches consist of an estimation phase, in which the health state of the system is first identified, and a prediction phase, in which the health state is projected forward in time to determine the end of life. Centralized solutions to these problems are often computationally expensive, do not scale well as the size of the system grows, and introduce a single point of failure. In this paper, we propose a novel distributed model-based prognostics scheme that formally describes how to decompose both the estimation and prediction problems into independent local subproblems whose solutions may be easily composed into a global solution. The decomposition of the prognostics problem is achieved through structural decomposition of the underlying models. The decomposition algorithm creates from the global system model a set of local submodels suitable for prognostics. Independent local estimation and prediction problems are formed based on these local submodels, resulting in a scalable distributed prognostics approach that allows the local subproblems to be solved in parallel, thus offering increases in computational efficiency. Using a centrifugal pump as a case study, we perform a number of simulation-based experiments to demonstrate the distributed approach, compare the performance with a centralized approach, and establish its scalability. Index Terms-model-based prognostics, distributed prognostics, structural model decomposition ABBREVIATIONS

centrifugal pump↗

NASA NTRS2019

X-Ray Photoelectron Spectroscopy

The interaction of photon and the electron goes back to the early part of 19th century emanating from the photo-electric effect depicted by none other than Albert Einstein (Ref 1) described in 1905, and the redistribution of kinetic energy resulting from the interaction of x-ray and solids reported during early part of the century (Ref.2). The spectrum resolutions obtained at that time was not sufficient to observe distinct peaks in spectra for materials. Thus, these phenomena hardly attracted any attention for many years following these discoveries. The modern X-ray Photoelectron Spectroscopy (XPS) has been possible by the extensive and significant contribution from Kai Siegbahn and others (Ref.3, 4) of Uppsala University. Siegbahn developed and employed a high-resolution electron spectrometer that revealed electron peaks in a spectrum emerging from the interaction of x-rays and solids. Eventually, Kai Siegbahn received Nobel Prize in 1981 for his contributions to XPS. Around 1958, shifts in elemental peaks were realized in compounds when the same elements are bound to other but different elements. This discovery resulted in the chemical state identification in various chemicals as well as the oxidation states of atoms in compounds. Because of these useful physical effects, the Uppsala group named XPS with a synonymous name of ESCA (Electron Spectroscopy for Chemical Analysis) used widely today and will be used here alternatively. Therefore, XPS or ESCA not only identifies the element, but also the compound these elements form, from their chemical shifts. Compared to other micro-analytical techniques such as Energy Dispersive (EDS) or Wavelength Dispersive (WDS) techniques, XPS analyzes only few atomic layers present on the surface. This was discovered early in 1966 (Ref. 5). While this has awarded a merit to the analytical technique to analyze very thin layers such as films and coatings, it often analyzes the adsorbed superficial gases and contaminations on a sample introduced to its analytical chamber. This necessitates the surface is cleaned and the underlying material, material of interest, is exposed in a clean environment such that the material of interest is analyzed. The cleaning is accomplished by a scanning ion gun within the analytical chamber of the instrument. Ion gun uses an argon gas and is commonly attached in most modern machines. Reliable and efficient vacuum systems employed in modern machines does not allow adsorbed layers to rebuild after the surface is cleaned. Development of efficient and reliable vacuum pumps over these developmental years is yet another important step in the commercialization of XPS machines. Vacuum levels of better than 10-7 torr are essential to increase the mean free path of electrons released from the sample surface. Thus, modern machines are equipped with high capacity ion, turbo or cryogenic pumps in their analytical chambers. Today, XPS has advanced from an applied physics laboratory to industry for use in quality control as well as analysis of contaminants and has taken a dominant role in microanalysis. Its uniqueness arises from the fact that it is considered non-destructive compared to other common micro-analytical techniques using the electron and ion excitation sources. Polymers and plastics could be analyzed since the binding energies of saturated and unsaturated bonds in atoms could be separated. Extremely thin layers could be analyzed including materials with layered structures. The technique, though did not advance for many years, has now opened a new window for research as well as applications in industry due to its ability to separate and measure the chemical shifts in bound elements. Principles

Panda, Binayak↗

DOE OSTI2021

Cooling systems having an integrated ionic liquid salt dehumidification system

A cooling systems utilizes an organic ionic salt composition for dehumidification of an airflow. The organic ionic salt composition absorbs moisture from an inlet airflow to produce an outlet airflow with a reduce moisture from that of the inlet airflow. The organic ionic salt composition may be regenerated, wherein the absorbed moisture is expelled by heating with a heating device. The heating device may be an electrochemical heating device, such as a fuel cell, an electrochemical metal hydride heating device, an electrochemical heat pump or compressor, or a condenser of a refrigerant cycle, which may utilize an electrochemical pump or compressor. The efficiency of the cooling system may be increased by utilization of the waste heat the cooling system. The organic ionic salt composition may circulate back and forth or in a loop between a conditioner, where it absorbs moisture, to a regenerator, where moisture is desorbed by heating.

Bahar, Bamdad↗