This document summarizes the assessment of a diagnostic procedure for monitoring and controlling industrial processes. Specifically, it analyzes the monitoring of compressed air used in a blow molding process at a packaging company. Two approaches are evaluated: univariate analysis using a CUSUM control chart based on a key performance index, and multivariate analysis using principal component analysis to construct T2, residual, and bi-plot control charts. The multivariate approach effectively identifies days with different energy performance and production levels, while the univariate CUSUM chart shows the energy performance trend over time but cannot isolate individual events. Removing temperature from the multivariate analysis shows it is insensitive to uncorrelated variables.
1. What is Energy
2. Type of Energy
3. What is Energy Audit
4. Definition of Energy Audit
5. The Need for Energy Audit
6. Why Energy Audit
7. Preliminary Energy Audit
8. Targeted Energy Audit
9. Energy Pyramid
10. Energy Costs in Indian Scenario
Energy Cost Reduction Consultants, Energy Audit Services, Energy Consulting F...SudhanshGupta5
Energy Audit is an instrument for Analyzing energy efficiency potential and measures. An energy review is a significant device or strategy for discovering such possibilities for energy proficiency measures and evaluating their monetary practicality, which can be completed at various levels.
An approach to evaluate the heat exchanger retrofit for installed industrial ...eSAT Journals
Abstract This is part 2 of the conducted study to develop a new systematic method to evaluate the heat exchanger retrofit on existing industrial gas turbines. A new approach has been introduced and validated in the first part comparing with the measured data. This method was used to optimize the obtained cycle performance characteristics and the generated heat exchanger design options based on technical prospective to attain the highest possible improvement on the simple cycle performance. However, it is essential to consider the economic viability of using the recuperative cycle which will be investigated in thispaper. Although that there are several tools which can be used to achieve that objective, this study uses the Net Present Value (NPV) method due to its simplicity and accuracy. The established technique has been applied for the same described gas turbine cycles in the previous part. Based on the stated assumptions, it was found that by applying the recuperation in the first engine,W6BRC, and at full load and 100% utilization factor conditions, the payback period has increased by one year by applying over that of simple cycle. Moreover, at the end of the project life, the recuperative cycle of this engine is expected to achieve an increase of $11M in the NPV over that of simple cycle. This difference between the two cycles becomes greater in the case of the second engine, W7FA, which is ranging between $33.9M and $46.8M.However, the drop in the availability of the overall recuperative gas turbine by about 18% over the simple cycle gas turbine causes the NPV of both cycles to be equal. Moreover, this paper includes a sensitivity study to investigate the effects of utilization factor and recuperator effectiveness and pressure drop on the cumulative discounted cash flow. KeyWords:new systematic method,economic viability, Net Present Value, utilization factor,availability
Defining monitoring & targeting, Elements of monitoring & targeting, Data and information-analysis, Techniques -energy consumption,Production, Cumulative sum of differences (CUSUM).
1. What is Energy
2. Type of Energy
3. What is Energy Audit
4. Definition of Energy Audit
5. The Need for Energy Audit
6. Why Energy Audit
7. Preliminary Energy Audit
8. Targeted Energy Audit
9. Energy Pyramid
10. Energy Costs in Indian Scenario
Energy Cost Reduction Consultants, Energy Audit Services, Energy Consulting F...SudhanshGupta5
Energy Audit is an instrument for Analyzing energy efficiency potential and measures. An energy review is a significant device or strategy for discovering such possibilities for energy proficiency measures and evaluating their monetary practicality, which can be completed at various levels.
An approach to evaluate the heat exchanger retrofit for installed industrial ...eSAT Journals
Abstract This is part 2 of the conducted study to develop a new systematic method to evaluate the heat exchanger retrofit on existing industrial gas turbines. A new approach has been introduced and validated in the first part comparing with the measured data. This method was used to optimize the obtained cycle performance characteristics and the generated heat exchanger design options based on technical prospective to attain the highest possible improvement on the simple cycle performance. However, it is essential to consider the economic viability of using the recuperative cycle which will be investigated in thispaper. Although that there are several tools which can be used to achieve that objective, this study uses the Net Present Value (NPV) method due to its simplicity and accuracy. The established technique has been applied for the same described gas turbine cycles in the previous part. Based on the stated assumptions, it was found that by applying the recuperation in the first engine,W6BRC, and at full load and 100% utilization factor conditions, the payback period has increased by one year by applying over that of simple cycle. Moreover, at the end of the project life, the recuperative cycle of this engine is expected to achieve an increase of $11M in the NPV over that of simple cycle. This difference between the two cycles becomes greater in the case of the second engine, W7FA, which is ranging between $33.9M and $46.8M.However, the drop in the availability of the overall recuperative gas turbine by about 18% over the simple cycle gas turbine causes the NPV of both cycles to be equal. Moreover, this paper includes a sensitivity study to investigate the effects of utilization factor and recuperator effectiveness and pressure drop on the cumulative discounted cash flow. KeyWords:new systematic method,economic viability, Net Present Value, utilization factor,availability
Defining monitoring & targeting, Elements of monitoring & targeting, Data and information-analysis, Techniques -energy consumption,Production, Cumulative sum of differences (CUSUM).
We are a young company promoted by IIT Alumni. We provide services which helps individuals and organizations to take the "Green Route" for cleaner future. Our services includes Energy Audit, EPCM for Renewable energy (Solar & Bio-mass) Projects, Technology Evaluation (Research & Analysis) and carbon management services(footprint, mitigation and branding)
The judicious and effective use of energy to maximize profits (minimize
costs) and enhance competitive positions”
The strategy of adjusting and optimizing energy, using systems and procedures so as to reduce energy requirements per unit of output while holding constant or reducing total costs of producing the output from these systems”
MSM - Multi-Layer Stream Mapping as a Combined Approach for Industrial Proces...António J. Baptista
Abstract
Nowadays achieving sustainable development is a global concern. The issue of unsustainability can be related to population growth and excessive consumption of natural resources. To tackle these issues, several management tools and methodologies have been developed in the last years, to assess, analyse and improve the environmental and economic performance of production systems. This work presents an approach based value stream mapping in order to assess and improve energy efficiency, environmental performance and financial performance of a production system. The developed approach can be applied to any industry or production system, where all the unit processes involved are identified and the inputs/outputs of each unit system quantified and easily perceived. Key environmental performance indicators and the corresponding eco efficiency ratios arise as outcomes of this approach, in which a Multi Layer Stream Mapping (MSM) with visual management attributes is created
An energy audit is an inspection survey and an analysis of energy flows for energy conservation in a building. It may include a process or system to reduce the amount of energy input into the system without negatively affecting the output. In commercial and industrial real estate, an energy audit is the first step in identifying opportunities to reduce energy expense and carbon footprint.
energy audit checklist
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energy audit checklist
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Industrial energy auditing and reportingVignesh Sekar
Industrial Energy Audit is defined as the verification, monitoring and analysis of energy use including submission of technical report containing all the recommendations for improving energy efficiency with cost analysis and an action plan to reduce consumption
Energy Audit and Analysis of an Institutional Building under Subtropical Clim...IJECEIAES
Evaluation and estimation of energy consumption are essential in order to classify the amount of energy used and the way it is utilized in building. Hence, the possibility of any energy savings potential and energy savings opportunities can be identified. The intention of this article is to study and evaluate energy usage pattern of the Central Queensland University campus’ buildings, Queensland, Australia. This article presents the field survey results from the audit of an office building and performance-related measurements of the indoor environmental parameters, for instance, indoor air temperature, humidity and energy consumption concerned to the indoor heating and cooling load. Monthly observed energy usage information was employed to investigate influence of the climate conditions on energy usage.
A New Solution to Improve Power Quality of Renewable Energy Sources Smart Gri...iosrjce
This particular article reveals a prototyped interface current control protocol which is ideal for
multilevel converters and it’s utilization with a three-phase cascaded H-bridge inverter. This kind of
administration approach utilizes a discrete-time type of the device to estimate the longer term benefit from the
current for many voltage vectors, as well as decides on the vector which in turn decreases an expense purpose.
A result of the multitude of voltage vectors obtainable in a multilevel inverter, numerous computations are
expected, producing challenging execution with this strategy in a typical control program. A new improved
strategic approach with the demonstration using physical framework as well as Matlab system significantly
decreases the number of computations without influencing the actual system’s effectiveness is suggested.
Experimental outcomes intended for five-level inverters confirm the suggested strategy. Additionally, author
considered the socio-environmental effects occurring due to carbon foot printing as per KYOTO protocol and
demonstrates the implementation of prototype carbon foot printing control sub-protocol for minimization of
carbon foot printing occurring due to microbial fuel cell micro-grid setup. Hence this will help to manage
attitudinal goals to improve electricity resource quality and efficiency.
We are a young company promoted by IIT Alumni. We provide services which helps individuals and organizations to take the "Green Route" for cleaner future. Our services includes Energy Audit, EPCM for Renewable energy (Solar & Bio-mass) Projects, Technology Evaluation (Research & Analysis) and carbon management services(footprint, mitigation and branding)
The judicious and effective use of energy to maximize profits (minimize
costs) and enhance competitive positions”
The strategy of adjusting and optimizing energy, using systems and procedures so as to reduce energy requirements per unit of output while holding constant or reducing total costs of producing the output from these systems”
MSM - Multi-Layer Stream Mapping as a Combined Approach for Industrial Proces...António J. Baptista
Abstract
Nowadays achieving sustainable development is a global concern. The issue of unsustainability can be related to population growth and excessive consumption of natural resources. To tackle these issues, several management tools and methodologies have been developed in the last years, to assess, analyse and improve the environmental and economic performance of production systems. This work presents an approach based value stream mapping in order to assess and improve energy efficiency, environmental performance and financial performance of a production system. The developed approach can be applied to any industry or production system, where all the unit processes involved are identified and the inputs/outputs of each unit system quantified and easily perceived. Key environmental performance indicators and the corresponding eco efficiency ratios arise as outcomes of this approach, in which a Multi Layer Stream Mapping (MSM) with visual management attributes is created
An energy audit is an inspection survey and an analysis of energy flows for energy conservation in a building. It may include a process or system to reduce the amount of energy input into the system without negatively affecting the output. In commercial and industrial real estate, an energy audit is the first step in identifying opportunities to reduce energy expense and carbon footprint.
energy audit checklist
energy audit companies near me
mass save home energy assessment
home energy audit near me
do it yourself energy audit
energy audit free
free home energy audit
eversource energy audit
eversource home energy audit ct
energy audit checklist
energy audit report sample
what is an energy auditor
energy audit for home
energy audit equipment
energy audit program
home energy audit cost
energy audit ppt
interesting civil engineering topics
seminar topics pdf
civil engineering topics for presentation
civil seminar topics ppt
best seminar topics for civil engineering
seminar topics for mechanical engineers
civil engineering ppt
latest civil engineering seminar topics
Industrial energy auditing and reportingVignesh Sekar
Industrial Energy Audit is defined as the verification, monitoring and analysis of energy use including submission of technical report containing all the recommendations for improving energy efficiency with cost analysis and an action plan to reduce consumption
Energy Audit and Analysis of an Institutional Building under Subtropical Clim...IJECEIAES
Evaluation and estimation of energy consumption are essential in order to classify the amount of energy used and the way it is utilized in building. Hence, the possibility of any energy savings potential and energy savings opportunities can be identified. The intention of this article is to study and evaluate energy usage pattern of the Central Queensland University campus’ buildings, Queensland, Australia. This article presents the field survey results from the audit of an office building and performance-related measurements of the indoor environmental parameters, for instance, indoor air temperature, humidity and energy consumption concerned to the indoor heating and cooling load. Monthly observed energy usage information was employed to investigate influence of the climate conditions on energy usage.
A New Solution to Improve Power Quality of Renewable Energy Sources Smart Gri...iosrjce
This particular article reveals a prototyped interface current control protocol which is ideal for
multilevel converters and it’s utilization with a three-phase cascaded H-bridge inverter. This kind of
administration approach utilizes a discrete-time type of the device to estimate the longer term benefit from the
current for many voltage vectors, as well as decides on the vector which in turn decreases an expense purpose.
A result of the multitude of voltage vectors obtainable in a multilevel inverter, numerous computations are
expected, producing challenging execution with this strategy in a typical control program. A new improved
strategic approach with the demonstration using physical framework as well as Matlab system significantly
decreases the number of computations without influencing the actual system’s effectiveness is suggested.
Experimental outcomes intended for five-level inverters confirm the suggested strategy. Additionally, author
considered the socio-environmental effects occurring due to carbon foot printing as per KYOTO protocol and
demonstrates the implementation of prototype carbon foot printing control sub-protocol for minimization of
carbon foot printing occurring due to microbial fuel cell micro-grid setup. Hence this will help to manage
attitudinal goals to improve electricity resource quality and efficiency.
Plant-Wide Control: Eco-Efficiency and Control Loop ConfigurationISA Interchange
Since the eco-efficiency of all industrial processes/plants has become increasingly important, engineers need to find a way to integrate the control loop configuration and the measurements of eco-efficiency. A new measure of eco-efficiency, the exergy eco-efficiency factor, for control loop configuration, is proposed in this paper. The exergy eco-efficiency factor is based on the thermodynamic concept of exergy which can be used to analyse a process in terms of its efficiency associated with the control configuration. The combination of control pairing configuration techniques (such as the relative gain array, RGA and Niederlinski index, NI) and the proposed exergy eco-efficiency factor will guide the process designer to reach the optimal control design with low operational cost (i.e., energy consumption). The exergy eco-efficiency factor is implemented in the process simulation case study and the reliability of the proposed method is demonstrated by dynamic simulation results.
In today’s commercial buildings, installing an effective
WAGES (water, air, gas, electricity, steam) metering
system can be a source of substantial energy and cost
savings. This white paper examines WAGES metering
as the essential first step toward a comprehensive
energy management strategy. Best practices for
selecting meters, and identifying metering points are
described. In addition, metrics for measuring gains in
energy efficiency are explained.
life cycle cost analysis of a solar energy based hybrid power systemINFOGAIN PUBLICATION
The importance of life-cycle cost analysis of an integrated solar power system is explained in this paper. To analyze the energy power and cash flow computations, there exist many commercial types of energy audit softwares like Emat, Optimizer, Homer, Energy gauge, Treat and so on. Among the aforementioned audit softwares, homer software is selected since it consists of several built-in options to perform audit studies. Homer software basically utilizes the concept of finding the total net present cost to represent the life-cycle cost of the total system. This software is vividly used for obtaining the optimized energy audit solutions to integrate several equipments embedding into a single workable system.
Reinforcement Learning for Building Energy Optimization Through Controlling o...Power System Operation
This paper presents a novel methodology to control HVAC system and minimize energy cost
on the premise of satisfying power system constraints. A multi-agent architecture based on game theory and
reinforcement learning is developed so as to reduce the cost and computational complexity of the microgrid.
The multi-agent architecture comprising agents, state variables, action variables, reward function and cost
game is formulated. The paper lls the gap between multi-agent HVAC systems control and power system
optimization and planning. The results and analysis indicate that the proposed algorithm is benecial to deal
with the problem of ``curse of dimensionality'' for multi-agent microgrid HVAC system control and speed
up learning of unknown power system conditions.
A software algorithm/package for control loop configuration and eco-efficiencyISA Interchange
Software is a powerful tool to help us analyze industrial information and control processes. In this paper, we will show our recently development of a software algorithm/package which can help us select the more eco-efficient control configuration. Nowadays, the eco-efficiency of all industrial processes/plants has become more and more important; engineers need to find a way to integrate control loop configuration and measurements of eco-efficiency. The exergy eco-efficiency factor; a new measure of eco-efficiency for control loop configuration has been developed. This software algorithm/package will combine a commercial simulator, VMGSim, and Excel together to calculate the exergy eco-efficiency factor.
Benchmarking medium voltage feeders using data envelopment analysis: a case s...TELKOMNIKA JOURNAL
Feeder performance evaluation is a key component in improving the power system network.
Currently there is no proper method to find the performance of Medium Voltage Feeders (MVF) except the
number of feeder failures. Performance benchmarking may be used to identify actual performance of
feeders. The results of such benchmarking studies allow the organization to compare feeders with
themselves and identify poorly performing feeders. This paper focuses on prominent benchmarking
techniques used in international regulatory regime and analyses the applicability to MVFs.
Data Envelopment Analysis (DEA) method is selected to analyze the MVFs. Correlation analysis and DEA
analysis are carried out on different models and then the base model is selected for the analysis.
The relative performance of the 32 MVFs of Western Province, Sri Lanka is evaluated using the DEA.
Relative efficiency scores are identified for each feeder. Also the feeders are classified according to the
sensitivity analysis. The results indicate that the DEA analysis may be conveniently employed to evaluate
the performance of the MVFs. The evaluation is carried out once or twice a year with the MV distribution
development plan in order to identify the performance of the feeders and to utilize the available limited
resources efficiently.
Insights into the Efficiencies of On-Shore Wind Turbines: A Data-Centric Anal...Gurdal Ertek
Literature on renewable energy alternative of wind turbines does not include a multidimensional benchmarking study that can help investment decisions as well as design processes. This paper presents a data-centric analysis of commercial on-shore wind turbines and provides actionable insights through analytical benchmarking through Data Envelopment Analysis (DEA), visual data analysis, and statistical hypothesis testing. The paper also introduces a novel visualization approach for the understanding and the interpretation of reference sets, the set of efficient wind turbines that should be taken as benchmark by inefficient ones.
http://research.sabanciuniv.edu.
Insights into the Efficiencies of On-Shore Wind Turbines: A Data-Centric Anal...ertekg
Download Link > https://ertekprojects.com/gurdal-ertek-publications/blog/insights-into-the-efficiencies-of-on-shore-wind-turbines-a-data-centric-analysis/
Literature on renewable energy alternative of wind turbines does not include a multidimensional benchmarking studythat can help investment decisions as well as design processes. This paper presents a data-centric analysis of commercial on-shore wind turbines and provides actionable insights through analytical benchmarking through Data Envelopment Analysis (DEA), visual data analysis, and statistical hypothesis testing. The paper also introduces a novel visualization approach for the understanding and the interpretation of reference sets, the set of efficient wind turbines that should be taken as benchmark by inefficient ones.
This paper presents a novel approach for static transmission expansion planning and
allocation of the associated expansion costs to individual market entities in a restructured power
system. The approach seeks the optimal addition of transmission lines among the possible candidate
transmission lines minimizing the overall system costs and at the same time satisfying the system
operational and security constraints. Novelty of the approach lies in applying a widely known
technique used for overload security analysis to an area such as Transmission expansion planning.
Transmission expansion costs are allocated using distribution factors to the individual entities in a
fair and transparent manner. The results for modified Garver Test system demonstrate that the
approach with the advantage of its simplicity can be applied to transmission expansion planning and
cost allocation in restructured power system
Reliability Constrained Unit Commitment Considering the Effect of DG and DR P...IJECEIAES
Due to increase in energy prices at peak periods and increase in fuel cost, involving Distributed Generation (DG) and consumption management by Demand Response (DR) will be unavoidable options for optimal system operations. Also, with high penetration of DGs and DR programs into power system operation, the reliability criterion is taken into account as one of the most important concerns of system operators in management of power system. In this paper, a Reliability Constrained Unit Commitment (RCUC) at presence of time-based DR program and DGs integrated with conventional units is proposed and executed to reach a reliable and economic operation. Designated cost function has been minimized considering reliability constraint in prevailing UC formulation. The UC scheduling is accomplished in short-term so that the reliability is maintained in acceptable level. Because of complex nature of RCUC problem and full AC load flow constraints, the hybrid algorithm included Simulated Annealing (SA) and Binary Particle Swarm Optimization (BPSO) has been proposed to optimize the problem. Numerical results demonstrate the effectiveness of the proposed method and considerable efficacy of the time-based DR program in reducing operational costs by implementing it on IEEE-RTS79.
A probabilistic multi-objective approach for FACTS devices allocation with di...IJECEIAES
This study presents a probabilistic multi-objective optimization approach to obtain the optimal locations and sizes of static var compensator (SVC) and thyristor-controlled series capacitor (TCSC) in a power transmission network with large level of wind generation. In this study, the uncertainties of the wind power generation and correlated load demand are considered. The uncertainties are modeled in this work using the points estimation method (PEM). The optimization problem is solved using the multi-objective particle swarm optimization (MOPSO) algorithm to find the best position and rating of the flexible AC transmission system (FACTS) devices. The objective of the problem is to maximize the system loadability while minimizing the power losses and FACTS devices installation cost. Additionally, a technique based on fuzzy decision-making approach is employed to extract one of the Pareto optimal solutions as the best compromise one. The proposed approach is applied on the modified IEEE 30bus system. The numerical results evince the effectiveness of the proposed approach and shows the economic benefits that can be achieved when considering the FACTS controller.
Power System Reliability Assessment in a Complex Restructured Power SystemIJECEIAES
The basic purpose of an electric power system is to supply its consumers with electric energy as parsimoniously as possible and with a sensible degree of continuity and quality. It is expected that the solicitation of power system reliability assessment in bulk power systems will continue to increase in the future especially in the newly deregulated power diligence. This paper presents the research conducted on the three areas of incorporating multi-state generating unit models, evaluating system performance indices and identifying transmission paucities in complex system adequacy assessment. The incentives for electricity market participants to endow in new generation and transmission facilities are highly influenced by the market risk in a complex restructured environment. This paper also presents a procedure to identify transmission deficiencies and remedial modification in the composite generation and transmission system and focused on the application of probabilistic techniques in composite system adequacy assessment
EHR ATTRIBUTE-BASED ACCESS CONTROL (ABAC) FOR FOG COMPUTING ENVIRONMENTcsandit
Liquid level tanks are employed in many industrial and chemical areas. Their level must be keep
a defined point or between maximum-minimum points depending on changing of inlet and outlet
liquid quantities. In order to overcome the problem, many level control methods have been
developed. In the paper, it was aimed that obtain a mathematical model of an installed liquid
level tank system. Then, the mathematical model was derived from the installed system
depending on the sizes of the liquid level tank. According to some proportional-integralderivative
(PID) parameters, the model was simulated by using MATLAB/Simulink program.
After that, data of the liquid level tank were taken into a computer by employing data
acquisition cards (DAQs). Lastly, the computer-controlled liquid level control was successfully
practiced through a written computer program embedded into a PID algorithm used the PID
parameters obtained from the simulations into Advantech VisiDAQ software
Similar to Assessment of a diagnostic procedure for the monitoring and control of industrial processes (20)
2. 2 A. Corsini et al./ Energy Procedia 00 (2015) 000–000
higher or lower pressure can occur according to the demand profile. The share of electricity demand for the
production of CA is about 10% of the total energy consumption in a typical industrial plant. $0% of this
energy share could be attributed to losses [5,6]. Although a lot of studies have been carried on EE
technologies, still little is known about the functional and operational aspects [7-9]. The correct
interpretation of a process, necessarily invokes the definition of an Energy Performance Index (EnPI) to
help performance monitoring in energy management systems [10]. Several studies demonstrate the EnPI
pertinence to any kind of energy use [7, 11]. Focusing on CA, the typical and the simplest index measured
to verify the performance of the system is the SER (Service Energy Rate) or SEC (Specific Energy
Consumption), expressed as kWh/m3
of supplied air. The state of the art EnPI derivation [8] is coupled to
Simple Regression Model (SRM) to promote reliable functional indices [9].
The objective of the present work is to apply the use of monitoring data analysis, customary of industrial
product quality control, manufacturing process control and fault detection, to the energy analysis. In this
regard, two methodologies are applied advocating univariate and multivariate analysis in control chart
deviation. Open literature illustrates several methodologies to build control charts. Typically Shewhart,
EWMA, CUSUM techniques are used in the construction of univariate and multivariate charts [12-15].
Concerning the univariate analysis, instead of SER, a functional key performance index (KPI) was
proposed to correlate the production process metrics, and deduct information hidden in the variables
accounting for energy fluxes. The analysis of the time variation of the index was carried out first using the
univariate control chart (CUSUM chart) [12,13]. Concerning the multivariate approach (generally used in
industrial control systems) it was applied to the data set, evaluating mutual interaction of the process
variables with the aim to extract information about the energy consumption. Specifically, we have defined
the ensuing control chart, based on principal component analysis (PCA): T2
chart, residual chart and bi-plot
of PCA scores and loadings [16]. Notably, the analysis focused on the energy/operational audit of a real
industrial plant, data are collected from state of the art process oriented monitoring system.
In the following sections the case study is described. The models applied in the energy efficiency
analysis are discussed. Then, the results obtained through the use of the univariate and the multivariate
methodologies are shown, drawing attention to their flaws and strengths.
2. Methodology
2.1 CUSUM Control chart
In contrast to SEC or SER definitions, the proposed key performance index (KPI) links a dependent
variable e.g. air volume, with an independent one from the productive process. Notably, it was decided to
use the supplied air volume per unit of mass of raw material (HDPE). This index (m3
/kg HDPE) has been
selected because variables have the greatest correlation between them. The analyses were carried out on a
daily basis.
The KPI monitoring analysis was performed by creating a CUSUM chart with the variation of its
standard deviation [12, 14]. The CUSUM chart is a so-called card "with memory", also known as "exact
design card". Data time history is interrogated to define a target value. This value serves to verify the
process is "in control", and in the absence of external inefficiencies should be constant [12, 14]. As soon as
the standard deviation σ is calculated, by comparing actual m3
/kg HDPE to the target value, two control
limits are determined equal to ±4σ (namely upper UCL and lower control limit LCL). In order to be
considered "in control", the process must remain within the range identified by the UCL and LCL. The
construction of the control chart implies the definition of an auxiliary constant k equal to half of the
standard deviation. Finally, two cards were built as:
C+
card = max (0; m3
/kg HDPE index – ( Target value + k ) + C+
n-1 (1)
C-
card = min (0; m3
/kg HDPE index – ( Target value - k ) + C-
n-1 (2)
The process is in "negative drift" when the C+
chart shows an increasing trend that can also get out of
upper control limit, a "positive drift" when the chart C-
stands at values lower than the expected target.
2.2 Principal component based control charts
Principal Component Analysis (PCA) is a multivariate analysis technique first proposed for data
compression and classification [16]. The goal is to reduce the dimension of a data set by finding a new set
3. A. Corsini et al./ Energy Procedia 00 (2015) 000–0003
of variables, smaller than the original one, highlighting the information contained in the data. Information is
meant as the variation present in the sample, given by the correlations between the original variables. The
extracted variables, called Principal Components (PCs), are linear combinations of the original variables in
which the coefficients of the linear combination can be obtained from the eigenvectors of the covariance (or
correlation) matrix of the original data. PCs are uncorrelated with each other and ordered by decreasing
variance. The bi-plot of PCA scores and loadings is the method of representation that displays the data
formed by transforming the original ones into the space of the PCs (scores).The loading provides a measure
of the contribution of each variable to the principal components [15,16].
To further explore the multivariate approach, the T2
chart based on PCA was considered. T2
chart allows
the control of a vector of means for multiple characteristics, the variance/covariance matrix of the control
variables. When an "out-of-control" condition occurs, typically a follow-up chart can be created to indicate
which variables are most likely responsible for the alarm. The T2
statistics gives a measure of the distance
of a sample from the process mean within the plane defined by PC1 and PC2, and the squared PCA
residuals give a measure of the distance of a sample perpendicular to that plane. A high T2
statistic thus
indicates that a sample is exhibiting an extreme variation, but well-accounted for by the PCA model. A
high residual indicates that the sample is exhibiting a variation not well-accounted for by the PCA model.
3. Case Study data
The analysis was carried out at an international packaging company producing plastic bottles (HDPE,
extrusion blow moulding process) [17] at a rate of about one million bottles a day, distinguished by size,
colour and type. The global CA power capacity amounts to 2000 kW.
Figure 1. a) Power on/off day, b) Monitoring variables of production process.
Along the distribution line (which connects the supply system to end uses) there are two probes recording
the pressure (bar) and volumetric flow rate (l/s). The control system of the compressor is regulated by a
control unit [6-7].
Figure 1.a indicates the closing days of the production plant. Data are available on a daily basis. Data
include the volume of supplied air (m3
), number of per day bottles, cumulative weight (kg) of the HDPE,
the cumulative volume (ml) of the HDPE bottle, the bottles blowing time. The last three variables being
directly correlated. The main normalized monitoring variables of the production process are illustrated in
Figure 1.b The data are available for 223 days: from February 2013 to April 2013 and from September
2013 to April 2014. In the May-August 2013 period a lack of data was due to a malfunction of the control
unit. This period is indicated in Figure 1c by the vertical red line (day index 101).
4. Results and discussion
First, we analyze the methodology today used to the energy analysis in industrial process (KPI index
construction), in order to make a comparison with the methodologies proposed.
Figure 2 shows the KPI plot versus time. Solid vertical lines identify the shut-down days of the system,
while dashed line, correspond to upper end lower control limit calculated in terms of KPI standard
deviation. The peaks shown in the graph correspond to shut-down or low production days. Although setting
4. 4 A. Corsini et al./ Energy Procedia 00 (2015) 000–000
an appropriate index admissibility range is possible to identify the days with high or low efficiency. This
approach is limited by the definition of our KPI depends upon a two variable correlation.
Figure 2. EnPI index on time
The next step is the comparison with a univariate cumulative control chart based on the KPI under
scrutiny. In figure 3 shows the CUSUM Chart computed using the method of the standard deviation
explained in the previous paragraph. This second control chart provides more detailed information about
the energy performance of the system. In this case there the indication of a trend for the use of energy and
as such it is not able to display the individual piece of information. However, it is evident by vertical lines
that the days identified (by vertical lines) have a strong influence on the progress of the curve.
Figure 3. CUSUM chart with standard deviations (between the index m3
/kg HDPE value and the m3
/kg HDPE target value)
The performance of the CUSUM chart based on deviation is shown in Figure 3, together with the limit
values. The process is in "negative drift" (solid graph) when the C+
paper shows an increasing trend that
can also get out of control limits, a "positive drift" (dotted graph) when the paper C-
stands at values lower
than the expected target. One of the limits of this type of technique is its inertia, i.e. the inability to detect
punctual events under rapid modification of the operating regimes. As shown in the plot, in shut down days,
the solid drift curve grows rapidly and slowly returns to regular operation days. Similarly the dotted curve,
during high energy efficiency days, decrease and then grow again slowly. This weaken the "readability of
the chart" on a daily time step, demanding for remedial approaches such as the application of opportune
filters to isolate outliers tied to specific operating conditions of the system.
A last multivariate monitoring technique, customary of quality control, was applied to the CA energy
management. This technique includes the construction of three different control charts based on PCA: i. the
bi-plot of scores and loadings, ii. T2
control chart, and iii. its residual control chart. Daily data available
from the monitoring of compressed air flow (m3
/d), mass of HDPE (kg/d), energy consumption (kWh/d)
and temperature (°C) were analysed. The selected PCs were the first and the third (PC1, PC3) because
mostly correlated to the CA energy demand. Results are shown in Figure 4.
Figure 4.a represents the bi-plot of scores an loadings. This representation is able to show the
relationships between the analysed variables and to identify which monitoring variable is responsible for
deviation of the data from the optimum energetic behaviour of the system. As such linking back to the
cause of the malfunction. In Figure 4.a, the points lying in the x-range (-0.5 - 0) are the days of low
production and those in the x-range (0 – 0.5) correspond to the days of high production. Moreover, the
positive y region of the graph is populated by the events with low energy efficiency, in fact they show high
power consumption and reduced use of HDPE. Finally, the lower part the chart is populated by event
representing days with high energy efficiency. The group of points located far left, near (-1,0), correspond
to the shut-down days of the system.
5. A. Corsini et al./ Energy Procedia 00 (2015) 000–0005
Figure 4.b and Figure 4.c, then, illustrate respectively the T2
and its residual control charts. The grey
stripes represent the confidence intervals (or control limits) ranging from 85% to 90% and from 90% to
99% respectively.
Figure 4. Multivariate control chart based on PCA: (a) Bi-plot of scores and loading; (b) T2
control chart; (c) Residual control chart
Figure 5. Multivariate control chart based on PCA (a) Bi-plot of scores and loading; (b) T2
control chart; (c) Residual control chart
The days that exceed 95% confidence limit are defined as out-of-control layer and correspond to the
days of shut-down or startup of the plant. As evident, the T2
charts appear to be sensitive only to the on-off
status of the monitored CA system. To assess the limitation in describing a credible dynamic of the energy
management system a second control limit confidence interval is introduce (equal to 85%). Nevertheless,
also in this case, the out of layers now detect days with energy performance and production volume
variation without distinguishing under-performing or out-performing operations. It could be inferred that
this result depends on the model that lies behind the construction of the chart. In fact, considering the
standard deviation of the distances between the single points and the mean value of the points projected in
the PC1-PC3 plane, as obvious observing Figure 4.a, the cloud of points at greater y distance represent
high/ low energy efficient and high/low production volume.
In order to understand the behaviour of the model in presence of uncorrelated variables, this
methodology was applied again to the dataset, removing the ambient temperature (Figure 5). In this case
the components PC1 and PC2 have been selected.
The bi-plot of scores and loadings (Figure 5.a) features results insensitive to temperature because of the
specific selection of PCs. The T2
control chart, in Figure 5.b, also is very similar to the one constructed
including the ambient temperature influence (Figure 4.b). However, the residual control chart (Figure 5.c),
which represents the error in the T2
scheme, presents much higher values in presence of uncorrelated
variables.
5. Conclusions
In the present study we attempted to analyse the energy use of the compressed air production section of
a b
c
a
b
c
6. 6 A. Corsini et al./ Energy Procedia 00 (2015) 000–000
an industrial plant using three different methods in order to identify their critical issues and strengths. The
novelty of the work lies in the application of methods that are usually used in the industrial filed, but not in
the energetic field. First was found and calculated an ENPI, this index was used to build a usual CUSUM
control chart, based on the difference between the actual data and that provided by a linear regression.
Hence, a new CUSUM control chart (univariate) based on the standard deviation compared with the mean
value was built. Finally multivariate models were applied creating: a T2
control chart, a residual control
chart and a biplot of loadings and scores.
The findings indicate that the available sampling frequency of the data (daily) is too large for a proper
analysis of the energy system. The limit of the univariate control charts consists in the possibility of
analysing only one or a few monitoring variables at a time, thwarting the capture of all the process aspects
influencing the energy field. Also being cumulated cards, describe the system variation and not daily data
thus is unable to return quickly to the starting value.
The multivariate methods turn out to be the best response to the energetic analysis, however, the use of
PCA also shows different limitations in the analysis. The T2
control chart is not able to distinguish between
data that indicate high and low energy efficiency. Nevertheless, the bi-plot of loadings and scores
highlights the contribution of additional information which is obtained in the system. In fact, this chart is
able to detect the distribution of the data set between variables and identify any variable generating
problems. However, it is necessary to adequately analyze the influence of the variables that are not energy-
use-related in order to avoid analysis errors generation.
In conclusion, besides the improvements obtained in the industrial processes energy analysis field, still,
none of these models appears to be completely adequate, leading to the necessity of further methodologies
screening or ad hoc methodology development.
Copyright
Authors keep full copyright over papers published in Energy Procedia.
Acknowledgements
The authors are indebted with Ing. Eileen Tortora for fruitful discussion.
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Biography
Sara Feudo is an Environmental Engineer and PhD fellow in “Industrial production engineering”at Sapienza,
Univerity of Rome. She deals with energy efficiency and mathematical models for energy analysis of industrial
systems.
7. A. Corsini et al./ Energy Procedia 00 (2015) 000–0007
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