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At least 433 records · Page 24

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DOE OSTI2020

Modular thermal energy storage system

A thermal energy storage (TES) system includes a plurality of closely packed TES modules, each TES module having a shell enclosing a plurality of sealed tubes that each contain a TES media. A computer-controlled flow control system includes a flow distributor, for example a flow distributor having a plenum configured to receive a heat transfer fluid (HTF), and a plurality of control valves controlled by the computer to controllably distribute the HTF from the plenum to the plurality of TES modules. Sensor data from the TES modules, for example temperature, pressure, and/or flow data, is provided to the computer. In some embodiments the plenum includes two or more compartments with separate HTF flow ports, which may be provided to the controller at different temperatures.

Wirz, Richard E.↗

DOE OSTI2020

Development and Validation of a Simulation Testbed for the Intelligent Building Agents Laboratory (IBAL) Using TRNSYS

This paper documents the development and validation of a dynamic primary cooling and thermal storage system simulation testbed. The system simulation testbed, sIBAL, is based on the Intelligent Building Agents Laboratory (IBAL) at the National Institute of Standards and Technology (NIST), which is a research infrastructure and testbed for the development, evaluation, and demonstration of intelligent control algorithms. The sIBAL testbed developed in this project will serve as a virtual twin of the real facility for future control algorithm development. The details of the methodologies used to develop and validate the simulation testbed, which replicates the dynamic behaviors of the primary cooling and ice storage system in the IBAL facility, are presented. The simulation testbed was developed in TRNSYS using built-in component models and MATLAB functions to replicate the two water-cooled chillers, a thermal storage tank, pumps, valves and other components for four different operation modes. Experiments on IBAL components were designed and executed to generate experimental data for model development and verification of the simulation platform. The validation of the simulation results was carried out in two phases: 1) independent component simulations for the chillers and thermal storage tank, and 2) a combined testbed simulation of the entire hydronic system. Comparison of simulation results to the experimental data obtained from the IBAL facility showed errors within 1 °C for the temperatures outputs of both the chiller and the thermal storage model. The error is within an acceptable range for further intelligent control algorithms development. The findings from the study are summarized and presented along with areas where additional research is needed. In addition, data filtering procedures and model refinement measures utilized to improve the accuracy and accelerate the computation time of the simulation are presented.

cooling systems↗

DOE OSTI2021

Methods for separating isotopes from a sample of fission products

Systems and methods for efficient, effective, and safe separation and isolation of multiple isotopes (e.g., Mo, Zr, Ba, Sr, Te, and lanthanide isotopes) from fission products includes use of a plurality of chromatography columns, each containing a chromatographic resin formulated to target one or more particular isotopes. The system is operable in a “series” configuration to load the multiple columns by a single pass of the sample. Then, the system may be transitioned (e.g., using valves) to a “parallel” configuration in which multiple columns of the system may be operated simultaneously to elute targeted isotopes. Additional parallel operations of the columns, using different eluent compositions, may be used to elute different targeted isotopes. The system may be reconditioned in preparation for a subsequent sample.

Snow, Mathew S.↗

DOE OSTI2021

Devices for fluid management

Disclosed herein are embodiments of devices for managing fluid transport. In particular disclosed embodiments, the devices are used to manage fluid transport in reactor systems, such as bio-assessment systems, chemical synthesis reactors, and the like. The devices disclosed herein include fluid management devices, reservoir assemblies, valving systems, pumps, and combinations thereof. The devices disclosed herein are cost-efficient and user-friendly and can be implemented in a variety of reactor systems.

Iyer, Rashi↗

DOE OSTI2021

PWR decay heat removal system in which steam from the pressurizer drives a turbine which drives a pump to inject water into the reactor pressure vessel

In conjunction with a pressurized water reactor (PWR) and a pressurizer configured to control pressure in the reactor pressure vessel, a decay heat removal system comprises a pressurized passive condenser, a turbine-driven pump connected to suction water from at least one water source into the reactor pressure vessel; and steam piping configured to deliver steam from the pressurizer to the turbine to operate the pump and to discharge the delivered steam into the pressurized passive condenser. The pump and turbine may be mounted on a common shaft via which the turbine drives the pump. The at least one water source may include a refueling water storage tank (RWST) and/or the pressurized passive condenser. A pressurizer power operated relief valve may control discharge of a portion of the delivered steam bypassing the turbine into the pressurized passive condenser to control pressure in the pressurizer.

Graham, Thomas G.↗

DOE OSTI2021

Purging natural gas compressors

When a natural gas compressor completes its compression cycle, residual pressurized natural gas remains in the cylinders, valves, and conduits of the compressor. Gas leaks into the environment increasing greenhouse gas emissions and introducing safety concerns. The systems and methods herein provide ways for substantially reducing or eliminating leakage of natural gas to the atmosphere while the system sits idle between compression cycles.

Echter, Nicholas Paul↗

DOE OSTI2021

Performance of a Hybrid HVAC-Integrated Thermal Storage Device

Thermal equipment in buildings is a primary contributor to peak loads on the electrical grid. Thermal energy storage is a cost-effective strategy to decouple electric use from thermal loads, thus reducing grid peak costs for building owners. One method for storing thermal energy in a building is to integrate a phase change material (PCM) directly into the heating, ventilation, and air conditioning system. These systems often require additional glycol loops, pumps, valves, and heat exchangers to couple the storage to the cooling system and building space, which increases the complexity and cost. This work will discuss an alternate approach where the storage is added directly into the heat pump evaporator. A detailed two-dimensional finite difference heat transfer model of a PCM-refrigerant-glycol heat exchanger was developed to simulate the performance of this component. The fluid stream was discretized along the flow direction to capture changes in the fluid properties and local heat transfer rates, and the phase change material was discretized in both the x and y directions to capture the movement of the melt front. The model was used to understand the impact of different material and geometric properties on the charge and discharge characteristics of the device. Finally, a Ragone framework analogous to that used for electrochemical batteries was used to maximize the energy density and round-trip efficiency of the device while supplying loads appropriate for space cooling in buildings.

buildings↗

DOE OSTI2021

Polymer exhaust for eliminating extruder transients

An additive manufacturing method that includes an extruder providing a supply of working material and a nozzle connected with respect to the extruder, the nozzle directing the working material to a deposit surface. A diverter valve is positioned between the extruder and the nozzle to direct the working material to an exhaust port away from the deposit surface under certain conditions.

Chesser, Phillip C.↗

DOE OSTI2021

Design and Testing of a Water-Cooled Rotating Detonation Combustor at Elevated Operating Pressures - Abstract

This is an extended abstract being submitted for consideration that briefly describes the material that will be included in the final paper. This study will detail the design and testing of a water-cooled Rotating Detonation Combustor (RDC) that permits operation for extended periods of time ensuring that the device has reach a stable operating temperature. Extended run times also provides an opportunity to consider transient behaviors that occur as a result of altering the operating conditions such as equivalence ratio. The experimental setup is also unique in that it consists of a ducted exhaust with a downstream high-temperature valve that can control the pre-combustion pressure in the RDC independent of the combustor annulus and exit geometry. This paper will examine the results from the extended operation of the water-cooled RDC over a range of both transient and steady state equivalence ratios (0.5 - 1.0), pre-combustion operating pressures (0 - 207 kPa), mass flow rates (0.42 – 0.5 kg/sec) and air inlet throat area to combustor channel area ratios (0.09 – 0.32). All tests were performed while operating on hydrogen in air at a nominal air inlet temperature of 340 – 350 K. Limited data obtained at an elevated inlet air temperature of 480 K will also be discussed. Results suggest that under certain conditions the operating mode of the detonation wave can vary as it approaches a stable operating temperature. For the RDC tested, a stable operating temperature is not achieved until approximately 8-10 seconds of run time.

Ferguson, Donald↗

DOE OSTI2021

Method and apparatus for reduction of water re-evaporation in a dedicated dehumidifier/water heater

An apparatus that includes a refrigeration circuit that includes an evaporator, a first condenser and a compressor. The apparatus includes a refrigerant-water heat exchanger that includes a second condenser fluidly coupled to the refrigeration circuit. A control valve is operatively connected to the refrigeration circuit to direct flow of refrigerant through at least one of the first condenser during a dehumidification mode and the second condenser during a water heating mode. A damper is disposed on an upwind side of the evaporator, the damper being operable to reduce airflow across the evaporator during a ventilation mode.

Uselton, Robert B.↗

DOE OSTI2021

System and method for modifying material surface

The present disclosure relates to a method of modifying a surface of a material, in situ, while the material is being used to at least one of form or modify a portion of a part to remove flaws layer-by-layer and improve a part from a layerwise built, or a coating. The method may involve generating first, second and third beams. The third beam may act on a surface of a material to heat a portion of the surface of the material into a flowable state to thus modify a surface characteristic of the material. The first beam may control an optically addressable light valve (OALV) which modifies an energy of the third beam. The second beam may control an optically addressable electric field modulator (OAEFM) to generate an electric field in a vicinity of the surface and to influence a movement of the portion of material while the portion of material is in the flowable state. The beams are modulated based on a sensing element feedback loop.

Elhadj, Selim↗

DOE OSTI2021

Volumetric micro-injector for capillary electrophoresis

A volumetric microfluidic injector for capillary electrophoresis (CE) for highly repeatable sample injection has been designed and built to eliminate known injection bias in hydrodynamic injection. A defined volume from 1-10 nL or 0.1-100 nL of sample is confined in a defined region of a micro-valve PDMS microfluidic injector chip and electrophoretic potential is applied to drive sample into a separation device such as an embedded fused silica capillary for separation and detection. Using a 75 μm ID capillary, the RSD of an absorbance peak area as low as 1.32% (n=11) is obtained. As a comparison, the time-dependent injection was tested using the same chip which resulted in an inferior repeatability.

Ha, Noel Seunghyun↗

DOE OSTI2021

Dynamic Human-in-the-Loop Simulated Nuclear Power Plant Thermal Dispatch System Demonstration and Evaluation Study

An Idaho National Laboratory research team performed a human-in-the-loop study with two formerly licensed retired operators to evaluate thermal power dispatch operations supported by the modified GSE Systems GPWR plant simulator. Virtual representations of the analog control panels were presented on touch-screen bays configured to mimic the control room layout in the newly renovated Human Systems Simulation Laboratory. The operators performed 15 scenarios covering normal evolutions to transition the plant from full turbine operation to joint turbine and thermal power dispatch operations in addition to transient response scenarios induced with simulated faults to evaluate the impact of thermal power dispatch system on operator and plant responses. A prototype human-system interface (HSI) was developed and displayed in tandem with the virtual analog panels to support the operators executing the procedurally drive evolutions and transient responses. An interdisciplinary team of operations experts, nuclear engineers, and human factors experts observed the operators performing the scenarios to evaluate the operations. Only a preliminary analysis of the results has been performed. The full analysis will be shared in a milestone report scheduled for release at the end of September; however, some high-level conclusions were readily available. Two high level findings for the system design were captured in the study. The manual control supported by the HSI to transition from standard operations to thermal power dispatch operation imposed a considerable amount of workload on the operators due to tedious manual valve manipulations and system monitoring required to verify their intended effect. An additional operator would be required in the control room to support the daily evolution. Automatic control for the transition was deemed a requirement for plant adoption without imposing additional staffing costs. The second finding was the necessity for an automatic thermal power dispatch system trip isolation function linked to a turbine and reactor trip signal. The operators completed scenarios with automatic isolation functionality and manually required actuation of the thermal power dispatch system. The operator response was sufficiently slower in the manual trip condition, such that operators were unable to manually actuate key post trip safety functions an indicate a degraded control capability that should be avoided. With an automatic trip signal little to no impact of the thermal power dispatch system was identified on the primary plant response and therefore the system could be readily and safely adopted. Together these two findings represent the need to support the adoption of thermal power dispatch capability into existing operations by leveraging automation to augment any additional operator tasking required to control and monitor an additional system beyond existing operations.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2022

Design and Verification of An Open-Circuit Electro-Hydraulic Actuator System with An Integrated Electro-Hydraulic Unit

This paper proposes an electro-hydraulic actuator (EHA) system, and two novel-designed electro-hydraulic units (EHU) consisting of a fixed-displacement hydraulic pump and a variable-speed electric motor. Both the novel EHU designs integrate an electric machine and a hydraulic machine in a single unit, featuring compactness and power density. However, they differ for salient aspects such as power and electric machine cooling system. The EHA system features an open circuit design, where hydraulic hoses connect the EHU with a tank, a valve manifold, and the hydraulic cylinder. In this way, the proposed EHA technology can be used to implement distributed hydraulic actuation in a vehicle without requiring changes to the hydraulic actuators or at the overall layout of the hydraulic components with respect to the original vehicle design. A dedicated test rig is developed to verify the performance of the proposed EHA system. The efficiency of the EHA is measured in a steady state and under a realistic duty cycle of a commercial compact loader. The measured efficiency of the system can reach 54% with up to 20kN load and 6kW power level.

42 ENGINEERING↗

DOE OSTI2022

Cold Climate Integrated Heat Pump

This paper introduces development of a residential air-source integrated heat pump for cold climates (CCIHP). The heat pump is multi-functional to meet all the home comfort demands, including space cooling, space heating, domestic water heating and energy storage. The CCIHP is an ideal solution to decarbonize northern homes via providing efficient space heating and water heating to replace natural gas. It uses a three-stage compressor and a single set of heat exchangers and valves to deliver all the functions, and thus achieve cost reduction. We developed an innovative system configuration and related controls to solve typical charge unbalance in heat pumps, accelerate charge migration and smoothen mode transition in integrated heat pumps. Laboratory investigations were conducted for individual modes and verified the control functions. Laboratory tests demonstrated that the unit delivered outstanding performance. It achieved 17.0 SEER (seasonal cooling energy efficiency rating) and 11.0 HSPF (heating seasonal performance factor). In the most efficient mode (combined space cooling and water heating mode), the unit reached a total energy efficiency of 35.0 EER and required only 25 minutes to heat a 50-gallon tank of water. The CCIHP can heat 1.7 GPM water from 58 to 125°F in a direct flow-through, when the ambient temperature is above 47°F. In a dedicated water heating mode using outdoor air source, the heat pump operated down to 17°F, achieving a COP > 2.6, and heated 50-gallon water within 1 hour.

Shen, Bo↗

DOE OSTI2022

Reversible pump-turbine installation

The present invention is a reversible pump-turbine installation positioned in a vertical borehole instead of in a conventional underground powerhouse or deep concrete powerhouse. The required plant cavitation coefficient may be achieved by simply boring a vertical borehole to the required depth rather than routing the water flow to and from a deeply buried powerhouse. A pneumatically controlled pressure relief valve may be incorporated into this invention.

Obermeyer, Henry K.↗

DOE OSTI2022

Pressure feedback control of electro-hydraulic actuators using fixed displacement hydraulic machines

This paper presents the development of a control strategy for Electro-Hydraulic Actuator (EHA) systems based on fixed displacement hydraulic machines. Although some previous studies on EHAs show benefits in terms of energy efficiency and regeneration capability compared to conventional hydraulic systems, few studies focus on the dynamic performance of EHAs. Unlike traditional valve-controlled systems, an EHA based on a fixed displacement pump typically relies on variation of the electric motor shaft speed to control the actuator velocity. This study shows that pressure feedback can be used to control the speed of the electric machine, thus achieving the required actuator/machine dynamic response. A simulation model is developed by including the EM, the hydraulic system, and the actuation system, which can give a realistic prediction of the EHA performance for a typical duty cycle. An open-circuit EHA previously proposed by the authors is used to validate the control strategy, and the simulation results show superior dynamic performance, exhibiting a reduction in response time and oscillatory behavior, compared to a feedforward EHA controller. Following the method presented in this study, it is possible to design a controller with a pressure feedback strategy for EHA systems with different size and actuation requirements

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2022

Start-up and Emergency Shutdown Modeling for a Coal-fired 10MWe sCO₂ Power Plant

As part of a Phase II Front End Engineering Design (FEED) study for the DOE Fossil Fuel Large Scale Pilots program, investigations of novel start-up and emergency shutdown methods for a stoker-fed, coal-fired, 10MWe sCO₂ power plant proposal were performed. These investigations were performed using 1D transient system models of the plant created within the GT-SUITE system modeling platform. The system model components were created using vendor quotation data (heat exchangers), performance maps (turbomachines), or FMU models (fired heater). Previously, Echogen Power Systems (Echogen) has used a sCO₂ power cycle start-up method that fills the system with liquid CO₂ to facilitate easy use of an electrically-driven start pump to transition the system from initial CO₂ fill to turbo-compressor initialization. The novel start-up method presented attempts this transition with a minimal filling of the system with liquid CO₂, to reduce the total CO₂ inventory required. This method leaves the start pump vulnerable to a two phase inlet condition as system pressure is below the CO₂ saturation pressure for the condenser cooling water temperature (Tcw). System model cases at Tcw of 18°C, 26°C, and 32°C, corresponding to cold, design, and hot ambient days, were analyzed to determine if the SP inlet condition could be kept as a subcooled liquid and estimate the CO₂ inventory reduction amount./p> Stoker-fed, coal-fired heaters continue to emit heat for some time even after emergency shutdown from events such as a power failure. This heat emission would lead to a failure of the fired heater, as the metal overheats, if the CO₂ flow is shut off. The emergency shutdown method presented utilizes CO₂ vented by a controllable vent valve (CRV) to provide CO₂ cooling flow to the fired heater. To determine the effectiveness of this method at keeping the fired heater peak tubing metal temperature below the ASME material temperature limit, for pressures below 5 MPa, of 816 °C, system model cases with CRV diameters ranging from 4” to 10”, and an alternative CO₂ vent routing with CRV size of 6”, were investigated./p>

01 COAL, LIGNITE, AND PEAT↗