Load sharing energy savings methodology for systems with multiple centrifugal compressors
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32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
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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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Identifying Energy Inefficiencies in Compressed Air Systems: A Systematic Approach with the Compressed Air Scoping Tool
This paper highlights the importance of improving compressed air systems, outlines the tool’s development and features, and underscores its value as a nonbiased resource for system evaluation and optimization. Additionally, the paper presents a case study based on a food manufacturing facility to demonstrate the practical application of the tool. Furthermore, the paper discusses potential future opportunities for enhancing the CA Scoping Tool.
compressed air benchmarking↗
Chapter 22: Compressed Air Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures (September 2011 - August 2020)
Compressed-air systems are used widely throughout industry for many operations, including pneumatic tools, packaging and automation equipment, conveyors, and other industrial process operations. Compressed-air systems are defined as a group of subsystems composed of air compressors, air treatment equipment, controls, piping, pneumatic tools, pneumatically powered machinery, and process applications using compressed air. A compressed-air system has three primary functional subsystems: supply, distribution, and demand. Air compressors are the primary energy consumers in a compressed-air system and are the primary focus of this protocol. The two compressed-air energy efficiency measures specifically addressed in this protocol are: high-efficiency/variable speed drive (VSD) compressor replacing modulating, load/unload, or constant-speed compressor; compressed-air leak survey and repairs. This protocol provides direction on how to reliably verify savings from these two measures using a consistent approach for each.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Gasoline fuels properties for multi-mode operation – Observations in a GDI and the CFR engine
The combustion behavior of five full boiling range RON98 gasoline blends was evaluated for multi-mode operation in a GDI and the CFR octane rating engine. The GDI engine tests were conducted with stoichiometric air-fuel ratio in spark-ignition (SI), and with air-diluted homogeneous charge compression ignition (HCCI) mode. In the CFR engine, the knocking combustion was analyzed under standard RON testing conditions at both peak knocking lambda and stoichiometric air-fuel ratios, whereas compression ignited operation was characterized by utilizing the HCCI number test protocol. Disparate knock limited SI and HCCI combustion behavior was observed for the test fuels, despite four of the fuels having the same RON and octane sensitivity. It was found that knock-limited combustion phasing in the GDI engine did not align well with the RON. However, a detailed comparison of knock-limited SI operation in the GDI and CFR engine revealed that a more appropriate effective RON based on a common knock intensity metric (MAPO) and stoichiometric air-fuel ratio resulted in comparable knock characterization between the two engine platforms. Furthermore, the critical intake air temperature and the critical compression ratio were proposed to characterize knock-limited SI operation, while the minimum intake air heating and compression ratio were used to define a fuel's autoignition propensity for compression ignition operation in the GDI and CFR engine, respectively. Finally, each fuel's characteristic compression ratio needed to obtain knock-limited SI (KLSI) and HCCI operation was used to calculate an effective multi-mode octane number (MM-ON) based on the primary reference fuel blends.
33 ADVANCED PROPULSION SYSTEMS↗
Cryomodule Compressed Air Panels
RF couplers require compressed air to maintain operational temperature and performance. Each type of cryomodule has a different configuration dependent on the number of RF cavities and their specifications. Compressed air panels will be mounted on the lifting brackets of the cryomodules to provide support for the hardware.
Herbst, Lilly↗
Compressed Air Scoping Tool Teaches Energy Efficiency Best Practices
Standards and practices around compressed air systems are evolving as previous golden rules become outdated and unhelpful. One of the most referenced guidelines gives us the perfect example: The previous rule of thumb for compressed air storage – 1-3 gal/cfm1,2 – is now accepted to be 3-5 gal/cfm. This change in recommended storage is only one of many in the industry, resulting in industrial users lost in a sea of contradictory best practices. To help combat confusion and poor information sharing, a collaborative effort between Oak Ridge National Laboratory (ORNL) and the Department of Energy’s (DOE’s) Better Plants program created the Compressed Air (CA) Scoping Tool with the most up-to-date best practices in the industry (as of 2023). It can be used as a nonbiased, one-stop shop for best practice recommendations. The Excelbased tool is designed to be an initial step in understanding the operation of a compressed air system, a baselining tool enabling users to comprehend various aspects of a facility’s system from the production of compressed air to its application by end users.
42 ENGINEERING↗
A case study of replacing pneumatic tools with battery-powered ones at an automobile assembly plant
Compressed air is ubiquitous in manufacturing facilities and vital for the proper operation of numerous types of manufacturing equipment and processes, but compressed air systems are highly inefficient. One way of reducing compressed air usage and the associated electricity consumption is to replace pneumatic tools with battery-powered ones. This paper studied the energy cost savings and return on investment (ROI) of replacing pneumatic torque wrenches with battery-powered ones at a typical automobile assembly plant. With a total triggered time of 400.6 hours and an assumed electricity rate of $0.10/kWh, the annual energy cost savings was estimated to be $104/year per tool. The simple payback period and ROI were 5.8 years and 17.3%, respectively.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Spectral broadening and compression of picosecond pulses in air using a multi-pass cell
We report the spectral broadening and post-compression of picosecond pulses using a multi-pass cell (MPC) operating in air. A 2 m-long bi-concave cavity with 41 reflections and 96.4% transmission was designed and implemented, optimized for the compression of 5.5 ps, 4.5 mJ pulses from a Yb:YAG laser operating at 1030 nm. A 19.3-fold spectral broadening was obtained, increasing the bandwidth from 0.3 nm to 5.8 nm, which enabled pulse compression down to 547 fs with a symmetric temporal profile close to the transform limit. These results demonstrate the feasibility of using open-air MPCs for high-energy picosecond pulse post-compression, without the need for sealed chambers, while preserving high mode quality and transmission. Scaling to pulse higher energy is discussed.
Zaldivar Escola, F. [Univ. of Buenos Aires (Argent↗
The novel Mechanical Ventilator Milano for the COVID-19 pandemic
This paper presents the Mechanical Ventilator Milano (MVM), a novel intensive therapy mechanical ventilator designed for rapid, large-scale, low-cost production for the COVID-19 pandemic. Free of moving mechanical parts and requiring only a source of compressed oxygen and medical air to operate, the MVM is designed to support the long-term invasive ventilation often required for COVID-19 patients and operates in pressure-regulated ventilation modes, which minimize the risk of furthering lung trauma. The MVM was extensively tested against ISO standards in the laboratory using a breathing simulator, with good agreement between input and measured breathing parameters and performing correctly in response to fault conditions and stability tests. The MVM has obtained Emergency Use Authorization by U.S. Food and Drug Administration (FDA) for use in healthcare settings during the COVID-19 pandemic and Health Canada Medical Device Authorization for Importation or Sale, under Interim Order for Use in Relation to COVID-19. Furthermore, following these certifications, mass production is ongoing and distribution is under way in several countries. The MVM was designed, tested, prepared for certification, and mass produced in the space of a few months by a unique collaboration of respiratory healthcare professionals and experimental physicists, working with industrial partners, and is an excellent ventilator candidate for this pandemic anywhere in the world
60 APPLIED LIFE SCIENCES↗
Methane Mitigation Thermoelectric Generator (MMTEG) (Final Scientific/ Technical Report)
Gas Technology Institute (GTI) has completed a $1.815M (plus $500K cost share), 54-month Co-operative agreement with the Department of Energy’s National Energy Technology Laboratory to develop a Methane Mitigation Thermoelectric Generator (MMTEG) system for gas field applications. This novel system uses fugitive gas to produce electrical power and consists of Thermoelectric Generators (TEG) driven by a linear burner, an air compressor, an accumulator, valves, batteries, and power electronics. The electrical power generated by the system is used to compress air and, in turn, the air is used to operate the pneumatic valves at the well site instead of using natural gas (NG) which would then be vented. The team completed the project objectives which included (1) Design, fabricate and test an integrated 6We nominal MMTEG prototype system, (2) Design a “retrofit kit” MMTEG system capable of being field tested at a gas well production site, and (3) build and test the field MMTEG system in a laboratory environment. Multiple system options were developed prior to selecting a “Passive” system which meets cost, NG savings, and greenhouse gas (GHG) reduction targets although not as efficient as initially planned. The MMTEG system is built primarily from commercial off-the-shelf parts (in some cases re-purposed) including the heat exchanger, heat rejection, electronic components, and also the TEGs. The team developed and implemented a novel system including the control system developed by Morrison Applied Sciences (MAS). The team completed incremental demonstrations of the hardware prior to the MMTEG system demonstration. A one-year simulation of the air delivery and battery charging subsystems was completed prior to the integration into the MMTEG system. In addition, the team simulated two-years of thermal cycles for integrated Burner/TEG/heat rejection subsystem. Finally, the entire MMTEG system was assembled, and troubleshooting was completed over a two-week period. Next, the MMTEG system was tested to simulate over 15 weeks of entire system operation over approximately four weeks in an accelerated test fashion with minimal intervention (such as changing fuel tanks). The MMTEG system met the key goals of a unit cost of under $1500 while saving 97% of NG expended today (including leakage) on average by pneumatic systems venting to the atmosphere. The MMTEG system reduced GHG emissions by 1000X (using the methane intensification factor of 28 relative to CO2). GTI is currently pursuing a field test of the MMTEG system. Interfacing with producers has provided additional insight into system improvements. Planned improvements include additional weather protection and control system improvements including the implementation of a long- range radio capability to notify operators if there is a fault.
03 NATURAL GAS↗
Techno-Economic Analysis of an SOFC Hybrid Carbon Conversion Concept
This is a presentation prepared for the 2023 Hydrogen and Fuel Cell Seminar to take place in Long Beach, CA on February 7-9, 2023. The presentation highlights analysis recently conducted by NETL on the cost and performance associated with operating SOFC systems in a hybridized configuration with compressed air energy storage.
Buchheit, Kyle L.↗
Predicting industrial building energy consumption with statistical and machine-learning models informed by physical system parameters
The industrial sector consumes about one-third of global energy, making them a frequent target for energy use reduction. Variation in energy usage is observed with weather conditions, as space conditioning needs to change seasonally, and with production, energy-using equipment is directly tied to production rate. Previous models were based on engineering analyses of equipment and relied on site-specific details. Others consisted of single-variable regressors that did not capture all contributions to energy consumption. Further, new modeling techniques could be applied to rectify these weaknesses. Applying data from 45 different manufacturing plants obtained from industrial energy audits, a supervised machine-learning model is developed to create a general predictor for industrial building energy consumption. The model uses features of air enthalpy, solar radiation, and wind speed to predict weather-dependency; motor, steam, and compressed air system parameters to capture support equipment contributions; and operating schedule, production rate, number of employees, and floor area to determine production-dependency. Results showed that a model that used a linear regressor over a transformed feature space could outperform a support vector machine and utilize features more representative of physical systems. Using informed parameters to build a reliable predictor will more accurately characterize a manufacturing facility's energy savings opportunities.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Controls Status for Fermilab’s PIP-II Project
Testing of Cryomodule first articles at PIP-II's on-site Cryomodule Test Facility (CMTF), where EPICS based controls are already being used, has been invaluable to the project. In addition to validating hardware and controls components, it has provided opportunities to build buy-in and illicit meaningful feedback early-on. A device naming convention has also been significantly refined with an internal working group and the PIP-II integration team. Compressed air and Process Control Water (PCW) systems have been installed, and operations has been engaged in Phoebus display development in preparation for a transition to operations for these systems by 2026. Cryoplant hardware has been put in place, and collaboration between controls and PIP-IIs cryo group for IOC and display development is well underway for commissioning of cryoplant systems to begin early 2026. The project has also received beneficial occupancy of the High-Bay Building in October 2025, keeping us on schedule for Warm Front End commissioning to begin in 2027.
Crisp, Dan [Fermilab]↗
Techno-Economic Analysis and Optimization of a Compressed-Air Energy Storage System Integrated with a Natural Gas Combined-Cycle Plant
To address the rising electricity demand and greenhouse gas concentration in the environment, considerable effort is being carried out across the globe on installing and operating renewable energy sources. However, the renewable energy production is affected by diurnal and seasonal variability. To ensure that the electric grid remains reliable and resilient even for the high penetration of renewables into the grid, various types of energy storage systems are being investigated. In this paper, a compressed-air energy storage (CAES) system integrated with a natural gas combined-cycle (NGCC) power plant is investigated where air is extracted from the gas turbine compressor or injected back into the gas turbine combustor when it is optimal to do so. First-principles dynamic models of the NGCC plant and CAES are developed along with the development of an economic model. The dynamic optimization of the integrated system is undertaken in the Python/Pyomo platform for maximizing the net present value (NPV). NPV optimization is undertaken for 14 regions/cases considering year-long locational marginal price (LMP) data with a 1 h interval. Design variables such as the storage capacity and storage pressure, as well as the operating variables such as the power plant load, air injection rate, and air extraction rate, are optimized. Results show that the integrated CAES system has a higher NPV than the NGCC-only system for all 14 regions, thus indicating the potential deployment of the integrated system under the assumption of the availability of caverns in close proximity to the NGCC plant. The levelized cost of storage is found to be in the range of 136–145 $/MWh. Roundtrip efficiency is found to be between 74.6–82.5%. A sensitivity study with respect to LMP shows that the LMP profile has a significant impact on the extent of air injection/extraction while capital expenditure reduction has a negligible effect.
25 ENERGY STORAGE↗
NFE-24-10417: Durability and Life-time Energy Performance Enhancement of Vapor Compression Systems
This project investigated the use of a Centrifugal Particle Separation (CPS) system to improve the durability and operational reliability of outdoor heat exchangers in vapor-compression based heating, ventilation, air conditioning, and refrigeration (HVACR) systems. The developed method introduced a novel dust and fouling mitigation approach by integrating an ambient air pre-cleaner that employs centrifugal forces to remove particulate matter from incoming air before it reaches the heat exchanger. By reducing the accumulation of dust and debris on coil surfaces, the CPS system aims to lower maintenance requirements and extend equipment lifespan. The project specifically involves coupling a centrifugal air pre-cleaner with a single-zone ductless mini-split system and evaluating its effectiveness in maintaining cleaner coil surfaces. Additionally, the study examined the impact of CPS integration on system energy performance. Through controlled experimental testing and performance monitoring, this work seeks to validate CPS-based air pre-cleaning as a practical, efficient solution for mitigating outdoor coil dust accumulation and fouling in both residential and commercial HVACR applications.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Mechanical Ventilator Milano (MVM): A Novel Mechanical Ventilator Designed for Mass Scale Production in Response to the COVID-19 Pandemics
We present here the design of the Mechanical Ventilator Milano (MVM), a novel mechanical ventilator designed for mass scale production in response to the COVID-19 pandemics, to compensate for the dramatic shortage of such ventilators in many countries. This ventilator is an electro-mechanical equivalent of the old, reliable Manley Ventilator. Our design is optimized to permit large sale production in short time and at a limited cost, relying on off-the-shelf components, readily available worldwide from hardware suppliers. Operation of the MVM requires only a source of compressed oxygen (or compressed medical air) and electrical power. The MVM control and monitoring unit can be connected and networked via WiFi so that no additional electrical connections are necessary other than the connection to the electrical power. At this stage the MVM is not a certified medical device. Construction of the first prototypes is starting with a team of engineers, scientists and computing experts. The purpose of this paper is to disseminate the conceptual design of the MVM broadly and to solicit feedback from the scientific and medical community to speed the process of review, improvement and possible implementation.
Galbiati, C.↗
Effect of geometry and operational parameters on the dehumidification performance of a desiccant coated heat exchanger
Solid desiccant dehumidification systems are an alternative to vapor-compression-based air dehumidification systems. They use solid desiccant materials to adsorb air moisture in space cooling. DCHE can integrate the cooling component in the heat exchanger to achieve higher dehumidification capacity. Comprehensive numeric modeling would be necessary to assist in the design and operation of the DCHE under development to achieve maximum performance. Here, we provide the details of a heat and mass transfer model developed for this purpose. The model aims to cover a gap in existing models by independently modeling heat transfer on the solid desiccant, fin, and tube. The model results were compared with an experimental reference for validation. The air outlet humidity and temperature results for dehumidification and regeneration showed a deviation lower than 15% from the experiment. The validated model was used to perform a parametric study for a series of design and operating conditions. The parametric analysis showed that an increase of 25% in desiccant layer thickness and thermal contact resistance between solid elements reduces moisture removal by 9.1% and 1%, respectively. These results indicate the need to independently model the desiccant layer.
42 ENGINEERING↗
Finding a common ground for RCM experiments. Part B: Benchmark study on ethanol ignition
Rapid compression machines (RCMs) are widely used to investigate gas phase reaction kinetics of various kind of fuels at application relevant conditions. In principle, the operation of an RCM is based on the idea of compressing a homogenous pre-mixed fuel-air mixture by a piston. Usually creviced pistons ensure a homogenous adiabatic core in the center of the reaction chamber which permits the assumption of an isentropic relation between the measured pressure and gas temperature. Despite the ideal core gas compression, non-ideal effects such as heat loss, differences in the compression behavior, and ultimately non-standardized design and operation of rapid compression machines lead to different experimental results in different facilities at nominally the same end of compression conditions. In this study ignition delay times of ethanol are investigated at four different conditions in five independent RCMs. As expected, the raw results of the different facilities indeed show notable differences at the same end of compression conditions. However, according to the adiabatic core hypothesis the agreement between kinetic simulations and experiments should be consistent for all facilities provided that the facility effects are correctly accounted for. To elaborate upon this hypothesis, a kinetic mechanism is optimized to reflect the experimental results of all facilities. In the end, the optimized mechanism predicts all experimental data within the expected uncertainty. This confirms the reliability of RCM experiments for kinetic investigations and the validity of the effective volume approach in simulating RCM data.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗