scholarly journals Numerical Thermal Analysis and 2-D CFD Evaluation Model for An Ideal Cryogenic Regenerator

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 361 ◽  
Author(s):  
Natheer Almtireen ◽  
Jürgen J. Brandner ◽  
Jan G. Korvink
Keyword(s):  
High Reliability ◽  
Low Cost ◽  
Evaluation Model ◽  
Volumetric Flow Rate ◽  
Cooling Capacity ◽  
Heating And Cooling ◽  
The Matrix ◽  
Overall Performance ◽  
Application Requirements ◽  
Vital Element

Regenerative cryocoolers such as Stirling, Gifford–McMahon, and pulse tube cryocoolers possess great merits such as small size, low cost, high reliability, and good cooling capacity. These merits led them to meet many IR and superconducting based application requirements. The regenerator is a vital element in these closed-cycle cryocoolers, but the overall performance depends strongly on the effectiveness of the regenerator. This paper presents a one-dimensional numerical analysis for the idealized thermal equations of the matrix and the working gas inside the regenerator. The algorithm predicts the temperature profiles for the gas during the heating and cooling periods, along with the matrix nodal temperatures. It examines the effect of the regenerator’s length and diameter, the matrix’s geometric parameters, the number of heat transfer units, and the volumetric flow rate, on the performance of an ideal regenerator. This paper proposes a 2D axisymmetric CFD model to evaluate the ideal regenerator model and to validate its findings.

Impact of Operating Parameters on Beta Type Regenerative Stirling Machine Performances

2015 ◽  
Author(s):  
Houda Hachem ◽  
Ramla Gheith ◽  
Sassi Ben Nasrallah ◽  
Fethi Aloui
Keyword(s):  
High Efficiency ◽  
High Reliability ◽  
Water Flow Rate ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Operating Parameters ◽  
Fast Cool ◽  
Heating And Cooling ◽  
Cooling Water Flow Rate ◽  
Commercial Applications

Due to its high efficiency, fast cool-down, small size, light weight, low power consumption, high reliability, Stirling cycle machine has many successful commercial applications such as heating and cooling. In the present paper, performances of a Beta type Stirling machine having a regenerative displacer were investigated. Energy analysis is reproduced taking into account complex phenomena related to compressible fluid mechanics, thermodynamics and heat transfer. A special attention is paid to the effect of such operating parameters as pressure, temperature, frequency and cooling water flow rate on Beta type regenerative Stirling machine performances. A MATLAB program was developed. Net cooling capacity, imputed work and COP inside the machine were assumed and compared to the experimental values. Comparing the results obtained by this code with experimental data, an acceptable agreement can be deduced for the predicted performance of the Stirling machine. The optimum speed is investigated.

Design of Control System of Acceleration and Deceleration of Stepper Motor Based on ATMEGA128

2013 ◽  
Vol 805-806 ◽  
pp. 1001-1006
Author(s):  
Jian Min Wang ◽  
Hai Bo Wei
Keyword(s):  
Control System ◽  
High Reliability ◽  
Low Cost ◽  
Stepper Motor ◽  
Effective Algorithm ◽  
Electromagnetic Device ◽  
Actual Effect ◽  
Acceleration And Deceleration ◽  
Overall Performance ◽  
High Torque

Stepper motor is a common electromagnetic device, the corresponding circuit of control and driver, effective algorithm of acceleration and deceleration play a very important role in improving overall performance. Many advantages were achieved using the control system based on ATMEGA128, such as higher simplicity, low cost, high reliability, high torque at low speeds, and high motion accuracy. At the same time, by using algorithm of acceleration and deceleration, the efficiency of stepper motor is further enhanced, and the actual effect of control of stepper motor is smooth and has good results.

Overall Performance Evaluation of Wind Power and Micro-CAES Hybrid Electricity-Generation System

2011 ◽  
Vol 130-134 ◽  
pp. 2676-2680
Author(s):  
Wen Yi Liu ◽  
Gang Xu ◽  
Yong Ping Yang
Keyword(s):  
Wind Power ◽  
Low Cost ◽  
Evaluation Model ◽  
Supply And Demand ◽  
Environment Protection ◽  
Turbo Expander ◽  
Overall Evaluation ◽  
Overall Performance ◽  
Supply Mode ◽  
Power Supply Mode

Micro-CAES can balance fluctuations in supply and demand of electricity. In this technology, air is compressed with a motor/generator using low cost, off-peak or discarded electricity from wind power and stored underground in caverns or pipes. This pressurized air is released then be burned with gas in a combustor. The hot expanding gases drive a micro-turbo expander and run a motor/generator which, in turn, produces electricity during peak demand periods. By considering the factors including economy, reliability, environment protection, and CO2 emission, a fuzzy overall evaluation model for different power supply mode is proposed. The related calculation and optimization are made. Linking with wind power, the overall performance of micro-CAES is best.

Modelling of bacterial removal in wastewater storage reservoir for irrigation purposes: a case study in Sicily, Italy

2003 ◽  
Vol 3 (4) ◽  
pp. 169-175 ◽  
Author(s):  
S. Barbagallo ◽  
F. Brissaud ◽  
G.L. Cirelli ◽  
S. Consoli ◽  
P. Xu
Keyword(s):  
Municipal Wastewater ◽  
High Reliability ◽  
Low Cost ◽  
Public Awareness ◽  
Storage System ◽  
Wastewater Reuse ◽  
Order Kinetic ◽  
Aquifer Recharge ◽  
Mediterranean Countries ◽  
Storage Reservoirs

In arid and semiarid regions the reclamation and reuse of municipal wastewater can play a strategic role in alleviating water resources shortages. Public awareness is growing about the need to recycle and reuse water for increasing supply availability. Many wastewater reuse projects have been put in operation in European and Mediterranean countries adopting extensive treatment systems such as aquifer recharge, lagooning, constructed wetlands, and storage reservoirs, mainly for landscape and agricultural irrigation. In agricultural reuse systems, there is an increasing interest in extensive technologies because of their high reliability, and easy and low cost operation and maintenance. Wastewater storage reservoirs have become the option selected in many countries because of the advantages they present in comparison with other treatment alternatives, namely the coupling of two purposes, stabilization and seasonal regulation. This paper describes an example of a wastewater storage system, built in Caltagirone (Sicily, Italy). The storage results in a tertiary treatment of a continuous inlet flow of activated sludge effluents. The prediction of the microbiological water quality has been evaluated by means of a non-steady-state first-order kinetic model. Single and multiple regressions were applied to determine the main variables that most significantly affected die-off coefficients. The proposed model has been calibrated using the results of a field monitoring carried out during a period from March to October 2000.

scholarly journals Automated Residential Energy Audits Using a Smart WiFi Thermostat-Enabled Data Mining Approach

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2500
Author(s):  
Abdulrahman Alanezi ◽  
Kevin P. Hallinan ◽  
Kefan Huang
Keyword(s):  
Low Cost ◽  
Model Development ◽  
Cost Savings ◽  
Measured Temperature ◽  
Single Family ◽  
Furnace Efficiency ◽  
Heating And Cooling ◽  
Data Mining Approach ◽  
Energy Auditing ◽  
Energy Audits

Smart WiFi thermostats, when they first reached the market, were touted as a means for achieving substantial heating and cooling energy cost savings. These savings did not materialize until additional features, such as geofencing, were added. Today, average savings from these thermostats of 10–12% in heating and 15% in cooling for a single-family residence have been reported. This research aims to demonstrate additional potential benefit of these thermostats, namely as a potential instrument for conducting virtual energy audits on residences. In this study, archived smart WiFi thermostat measured temperature data in the form of a power spectrum, corresponding historical weather and energy consumption data, building geometry characteristics, and occupancy data were integrated in order to train a machine learning model to predict attic and wall R-Values, furnace efficiency, and air conditioning seasonal energy efficiency ratio (SEER), all of which were known for all residences in this study. The developed model was validated on residences not used for model development. Validation R-squared values of 0.9408, 0.9421, 0.9536, and 0.9053 for predicting attic and wall R-values, furnace efficiency, and AC SEER, respectively, were realized. This research demonstrates promise for low-cost data-based energy auditing of residences reliant upon smart WiFi thermostats.

Electrostatic bellow muscle actuators and energy harvesters that stack up

2021 ◽  
Vol 6 (51) ◽  
pp. eaaz5796
Author(s):  
I. D. Sîrbu ◽  
G. Moretti ◽  
G. Bortolotti ◽  
M. Bolignari ◽  
S. Diré ◽  
...  
Keyword(s):  
High Performance ◽  
High Reliability ◽  
Low Cost ◽  
Artificial Muscle ◽  
Pressure Head ◽  
Robotic Systems ◽  
Maximum Pressure ◽  
Term Operation ◽  
Energy Harvesters ◽  
Out Of Plane

Future robotic systems will be pervasive technologies operating autonomously in unknown spaces that are shared with humans. Such complex interactions make it compulsory for them to be lightweight, soft, and efficient in a way to guarantee safety, robustness, and long-term operation. Such a set of qualities can be achieved using soft multipurpose systems that combine, integrate, and commute between conventional electromechanical and fluidic drives, as well as harvest energy during inactive actuation phases for increased energy efficiency. Here, we present an electrostatic actuator made of thin films and liquid dielectrics combined with rigid polymeric stiffening elements to form a circular electrostatic bellow muscle (EBM) unit capable of out-of-plane contraction. These units are easy to manufacture and can be arranged in arrays and stacks, which can be used as a contractile artificial muscle, as a pump for fluid-driven soft robots, or as an energy harvester. As an artificial muscle, EBMs of 20 to 40 millimeters in diameter can exert forces of up to 6 newtons, lift loads over a hundred times their own weight, and reach contractions of over 40% with strain rates over 1200% per second, with a bandwidth over 10 hertz. As a pump driver, these EBMs produce flow rates of up to 0.63 liters per minute and maximum pressure head of 6 kilopascals, whereas as generator, they reach a conversion efficiency close to 20%. The compact shape, low cost, simple assembling procedure, high reliability, and large contractions make the EBM a promising technology for high-performance robotic systems.

scholarly journals Brief Communication: A low-cost Arduino<sup>®</sup>-based wire extensometer for earth flow monitoring

2017 ◽  
Vol 17 (6) ◽  
pp. 881-885 ◽  
Author(s):  
Luigi Guerriero ◽  
Giovanni Guerriero ◽  
Gerardo Grelle ◽  
Francesco M. Guadagno ◽  
Paola Revellino
Keyword(s):  
High Reliability ◽  
Low Cost ◽  
Mitigation Measures ◽  
Thermal Drift ◽  
Data Logger ◽  
Test Configuration ◽  
Flow Monitoring ◽  
Earth Flow ◽  
Flow Displacement ◽  
Additional Monitoring

Abstract. Continuous monitoring of earth flow displacement is essential for the understanding of the dynamic of the process, its ongoing evolution and designing mitigation measures. Despite its importance, it is not always applied due to its expense and the need for integration with additional sensors to monitor factors controlling movement. To overcome these problems, we developed and tested a low-cost Arduino-based wire-rail extensometer integrating a data logger, a power system and multiple digital and analog inputs. The system is equipped with a high-precision position transducer that in the test configuration offers a measuring range of 1023 mm and an associated accuracy of ±1 mm, and integrates an operating temperature sensor that should allow potential thermal drift that typically affects this kind of systems to be identified and corrected. A field test, conducted at the Pietrafitta earth flow where additional monitoring systems had been installed, indicates a high reliability of the measurement and a high monitoring stability without visible thermal drift.

High-Reliability Low-Cost Gold Plating Connector

1993 ◽  
Author(s):  
Takashi Kamo ◽  
Hiroya Inaoka ◽  
Tetuo Kato ◽  
Tomio Hirano
Keyword(s):  
High Reliability ◽  
Low Cost ◽  
Gold Plating
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