scholarly journals Development of Thermal Performance Metrics for Direct Gas-Fired Circulating Heaters

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 588
Author(s):  
Benjamin C. Smith ◽  
Brett C. Ramirez ◽  
Steven J. Hoff

Many climate-controlled agricultural buildings use direct gas-fired circulating heaters (DGFCH) for supplement heat. There is no standardized test to calculate thermal efficiency for these heaters. This study aimed to develop a measurement system and analytical analysis for thermal efficiency, quantify the measurement uncertainty, and assess economics of DGFCH efficiency. The measurement system developed was similar to the ASHRAE 103 standard test stand with adaptations to connect the apparatus to the DGFCH. Two different propane measurement systems were used: input ratings < 30 kW used a mass flow system and input ratings > 30 kW used a volumetric gas meter. Three DGFCHs (21.9, 29.3, 73.3 kW) were tested to evaluate the system. Thermal efficiencies ranged from 92.4% to 100.9%. The resulting uncertainty (coverage factor of 2; ~95% Confidence Interval) ranged from 13.1% to 30.7% for input ratings of 56.3 to 11.4 kW. Key sources of uncertainty were propane and mass flow of air measurement. The economic impact of 1% difference in thermal efficiency ranged from USD $61.3 to $72.0 per heating season. Refinement of the testing system and procedures are needed to reduce the uncertainty. The application of this system will aid building designers in selection of DGFCHs for various applications.

2000 ◽  
Vol 2 (3) ◽  
pp. 191-200
Author(s):  
Tanja Niemel\"a ◽  
Markku Lepp\"anen ◽  
Minna P\"aivinen ◽  
Markku Mattila

Ergonomic properties of a pair of pruning shears were tested using a new laboratory measurement system for non-powered hand tools. With this system, it is possible to measure simultaneously the EMG activity of two muscles, the opening angle of hand tool blades by means of a potentiometer and, by means of strain gages, the force transmitted to the handle. A measurement system was tested by comparing the forces needed to cut wood of a certain diameter, and the actual force required, as measured by a material-testing system. The correlation between forearm flexor muscle activity and the compression force created by the user was investigated. The evaluation of the experimental testing system for non-powered hand tools has shown that there are methods for the measurement of force demand and opening angle. However, some improvements are recommended before this measurement system is used widely in the field.


2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Paul F. Beard ◽  
Thomas Povey ◽  
Kamaljit S. Chana

A turbine efficiency measurement system has been developed and installed on the turbine test facility (TTF) at QinetiQ Farnborough. The TTF is an engine-scale short-duration (0.5s run time) rotating transonic facility, which can operate as either single stage (HP vane and rotor) or 112 stage (HP stage with IP or LP vane). The current MT1 HP stage is highly loaded and unshrouded and is therefore relevant to current design trends. Implementation of the efficiency measurement system forms part of the EU Turbine Aero-Thermal External Flows (TATEF II) program. The following aspects of the efficiency measurement system are discussed in this paper: mass-flow rate measurement, power measurement by direct torque measurement, turbine inlet and exit area traverse measurement systems, computation of efficiency by mass weighting, and uncertainty analysis of the experimentally determined turbine efficiency. The calibration of the mass-flow rate and torque measurement systems are also discussed. Emphasis was placed on the need for a low efficiency precision uncertainty, so that changes in efficiency associated with turbine inlet temperature distortion and swirl can be resolved with good accuracy. Measurements with inlet flow distortion form part of the TATEF II program and will be the subject of forthcoming publications.


2015 ◽  
Vol 16 (2) ◽  
pp. 132-158 ◽  
Author(s):  
Jeremy Paley ◽  
Julia Cottrill ◽  
Katherine Errecart ◽  
Aimee White ◽  
Carrie Schaden ◽  
...  

Purpose – The purpose of this paper is to describe the evolution of a common approach to impact assessment across the Global Libraries (GL) portfolio of grants. It presents an overview of two systems, the Performance Metrics (PMs) and the Common Impact Measurement System (CIMS). By providing a standard set of definitions and methods for use across countries, these systems enable grantees to collect data that can be compared and aggregated for the purpose of collective learning, improvement, accountability, and advocacy. Design/methodology/approach – The PMs offer a standard methodology to collect library project performance management data, whereas the CIMS is a standard survey of public library users. The paper describes how the PM and CIMS data are being visualized and used, with examples of findings and lessons learned. Findings – The paper cites examples of the type of PM and CIMS data available, with a focus on employment, gender, and case studies from Botswana and Indonesia. These highlights illustrate how libraries’ user demographics differ from other types of public internet access venues and how libraries can contribute to strong employment and growth. Research limitations/implications – The measurement systems rely on different partners collecting data for the same metrics across different countries; while each grantee adheres to a standard methodology, small procedural, and methodological differences are inevitable. Future research could focus on conducting similar studies elsewhere, outside the cohort of countries in the GL portfolio of grants. Practical implications – The paper offers insights and lessons for library agencies or institutions interested in implementing a common measurement system. Recognizing that few library projects have the resources to track a comprehensive set of indicators, a case study is presented about how smaller initiatives can adapt these systems to their needs. Social implications – The indicators described in this paper enable public libraries to shift their focus from services provided to the outcomes they help individuals and communities realize, potentially increasing the potency of their programming and advocacy. Originality/value – Common measurement systems are not new, but their application in the public library field is novel, as is the Data Atlas, a platform grantees use to compare results across metrics, track progress, and conduct advocacy.


Author(s):  
Michal Omámik ◽  
Ivan Baránek

Metrological Control of Selected Surface Types of a Mechanical Part by Using On-Machine Measurement System The paper is focused on the research of On-machine measurement systems for a CNC multi-axis milling machine. Research is aimed at the suitable selection of measuring parameters for On-machine measurement systems in order to reach an accurate and reliable quality control of the mechanical part. Theoretical information and overall concept of research are also presented.


Author(s):  
Vijayakumar Rajendran ◽  
Harichandran Ramasubbu ◽  
Karthick Alagar ◽  
Vignesh Kumar Ramalingam

An experimental study has been carried out to enhance a solar air heater’s performance by integrating artificial roughness through baffles on the absorber plate. In this paper, the thermal and energy matrices analysis of a Solar Air Heater (SAH) roughened with V up perforated baffles have been investigated. The effect of various mass flow rates on the SAH was analyzed with and without baffles. Experimental outputs like outlet air temperature, useful energy (heat) gain and thermal efficiency were evaluated to confirm the performance improvement. The baffled absorber plate SAH was found to give the maximum thermal efficiency and useful energy gain of 89.3% and 1321.37 W at a mass flow rate of 0.0346 kg/s, 13% and 12% higher than SAH without baffle. This result showed that the V up-shaped ribs in flow arrangement provide better thermal performance than smooth plate SAH for the parameter investigated. Energy matrices analysis and carbon dioxide mitigation of the SAH system were also analyzed.


2003 ◽  
Vol 785 ◽  
Author(s):  
Seth S. Kessler ◽  
S. Mark Spearing

ABSTRACTEmbedded structural health monitoring systems are envisioned to be an important component of future transportation systems. One of the key challenges in designing an SHM system is the choice of sensors, and a sensor layout, which can detect unambiguously relevant structural damage. This paper focuses on the relationship between sensors, the materials of which they are made, and their ability to detect structural damage. Sensor selection maps have been produced which plot the capabilities of the full range of available sensor types vs. the key performance metrics (power consumption, resolution, range, sensor size, coverage). This exercise resulted in the identification of piezoceramic Lamb wave transducers as the sensor of choice. Experimental results are presented for the detailed selection of piezoceramic materials to be used as Lamb wave transducers.


Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2950
Author(s):  
Vinod Kumar ◽  
Liqiang Duan

Coal consumption and CO2 emissions are the major concerns of the 21st century. Solar aided (coal-fired) power generation (SAPG) is paid more and more attention globally, due to the lesser coal rate and initial cost than the original coal-fired power plant and CSP technology respectively. In this paper, the off-design dynamic performance simulation model of a solar aided coal-fired power plant is established. A 330 MW subcritical coal-fired power plant is taken as a case study. On a typical day, three various collector area solar fields are integrated into the coal-fired power plant. By introducing the solar heat, the variations of system performances are analyzed at design load, 75% load, and 50% load. Analyzed parameters with the change of DNI include the thermal oil mass flow rate, the mass flow rate of feed water heated by the solar energy, steam extraction mass flow rate, coal consumption, and the plant thermal efficiency. The research results show that, as DNI increases over a day, the coal saving rate will also increase, the maximum coal saving rate reaches up to 5%, and plant thermal efficiency reaches 40%. It is analyzed that the SAPG system gives the best performance at a lower load and a large aperture area.


1990 ◽  
Vol 112 (1) ◽  
pp. 94-99 ◽  
Author(s):  
E. W. Beans

The thermal efficiency, work per unit mass, and work per unit volume of the simple Rankine and Brayton cycles are expressed in terms of seven independent variables using a simplified thermodynamic model. By requiring equal efficiency, equal work conditions, and the same maximum cycle temperature for both cycles, two necessary relationships are established between the seven independent variables. These two relationships along with two maximum work conditions produce a method for comparing required and selected properties. These comparisons provide useful guidelines for the selection of the cycle and cycle fluids. The comparison analysis shows that for a given application the more attractive cycle is strongly dependent upon the fluids selected.


Author(s):  
Tanja Niemelä ◽  
Markku Leppänen ◽  
Minna Päivinen ◽  
Markku Mattila

During the Eurohandtool Project an experimental testing system for non-powered hand tools was developed for laboratory testing. With this system, it is possible to measure simultaneously (1) the EMG activity of two muscles, (2) the opening angle of hand tool blades by means of a potentiometer and, (3) by means of strain gages, the force transmitted to the handle. The first part of evaluation of the system was to determine its time of warming-up, reliability, linearity and repeatability. This paper concentrates on the second part, during which the aim was to test the measurement system by comparing the forces needed to cut wood of a certain diameter, and the actual force required, as measured by a material-testing system. The correlation between forearm flexor muscle activity and the compression force created by the user was investigated. The evaluation of experimental testing system for non-powered hand tools has shown that there are methods to measure force demand, opening angle and EMG-activity simultaneously. However, it is recommended to make some improvements before this measurement system can be taken into widespread use.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ali Jaber Naeemah ◽  
Kuan Yew Wong

PurposeThe purpose of this paper is (1) to review, analyze and assess the existing literature on lean tools selection studies published from 2005 to 2021; (2) to identify the limitations faced by previous studies; and (3) to suggest future works that are necessary to facilitate the selection of lean tools.Design/methodology/approachA systematic approach was used in order to identify, collect and select the articles. Several keywords related to the selection of lean tools were used to collect articles from different Scopus indexed journals. Next, the study systematically reviewed and analyzed the selected papers to identify the lean tools' selection method and discussed its features and limitations.FindingsAn analysis of the results showed that previous studies have adopted two types of methods for selecting lean tools. First, there are various traditional methods being used. Second, multi-criteria decision-making (MCDM) methods were commonly used in previous studies, such as the multi-objective decision-making method (MODM), single multi-attribute decision-making (MADM) methods and hybrid (MCDM). Moreover, the study revealed that the lean tools' selection methods in previous studies were based on evaluating the relationship between either lean tools and performance metrics or lean tools and waste, or both.Research limitations/implicationsIn terms of its theoretical value, the study is considered as an extension of the previous researches performed on this topic by determining and analyzing the features of the most selection methods of lean tools. Unlike previous review papers, this review had considered discussing and analyzing the characteristics and limitations of these methods. Section 2.2 of this paper reviewed some of the categories of MCDM methods as well as some of the traditional methods used in the selected previous studies. Section 2.1 of this paper explained the concept of lean management and its application benefits. Further, only three sectors were covered by the previous studies in this review paper. This study also provided recommendations for future research. Therefore, it provided researchers with a good conception of how to conduct the studies on lean tools selection. Besides, knowing the methods used in previous studies can help researchers develop new methods to select the best set of lean tools. That is, this study provided and advanced the existing knowledge base for researchers concerning lean tools selection, especially there is limited availability of review papers on this topic. Moreover, the study showed researchers the importance of the relationship between lean tools and indicators or/and performance indicators to determine the appropriate set of lean tools so that the results of future studies will be more realistic and acceptable.Practical implicationsPractically, manufacturers face a significant challenge when selecting proper lean tools. This study may enhance managers, manufacturers and company's knowledge to identify most of the methods used to choose the best set of lean tools and what are the advantages, disadvantages and limitations of these methods as well as the latest studies that have been adopted in this topic. That means this study can direct companies to prioritize the application of lean tools depending on either the manufacturing performance metrics or/and manufacturing wastes so that they avoid incorrect application of lean tools, which will add more non-value added activities to operations. Therefore companies can decrease the time and cost losses and enhancing the quality and efficiency of the performance. Correctly implementing the best set of lean tools in companies will lead in general to correctly applying lean management in corporations. Therefore, these lean tools can boost the economic aspect of companies and society through reducing waste, improving performance indicators, preserving time and cost, achieving quality, efficiency, competitiveness, boosting employee income and improving the gross domestic product. The correct lean tool selection reduces customer complaints and employee stress and improves work conditions, health, safety and labor wellbeing. Besides, the correct lean tools selection improves materials usage, energy usage, water usage and decreases liquid wastes, solid wastes and air emissions. As a result, the right selection of lean tools will have positive effects on both the environment and society. The study may also encourage manufacturers and researchers to adopt studies on lean tools selection in small- and medium-sized companies because the study referred to the importance and participation of these kinds of companies in a large proportion of the economy of developing countries. Further, the study may encourage some countries that have not previously adopted this type of study, academically and industrially to conduct lean tools selection studies.Social implicationsAs mentioned previously, the correct lean tool selection reduces customer complaints and employee stress and improves work conditions, health, safety and labor wellbeing. The proper lean tools selection improves materials usage, energy usage, water usage and decreases liquid wastes, solid wastes and air emissions. As a result, the right choice of lean tools will positively affect both the environment and society.Originality/valueThe study expanded the efforts of previous studies concerning lean management features. It provided an accurate review of most lean tools selection studies published from 2005 to 2021 and was not limited to the manufacturing sector. It further identified and briefly described the selection methods concerning lean tools adopted in each paper.


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