Oak Ridge National Laboratory
Official TM Cover: PEPEx Algorithm
Thomas Wenning
Sachin Nimbalkar
Kiran Thirumaran
3/2/2016
ORNL/TM-2017/73028
Energy and Transportation Science Division
PEPEx ALGORITHM
Thomas Wenning (Oak Ridge National Laboratory)
Sachin Nimbalkar (Oak Ridge National Laboratory)
Kiran Thirumaran (Oak Ridge National Laboratory)
Date Published: March 2, 2017
Prepared by
OAK RIDGE NATIONAL LABORATORY
Oak Ridge, TN 37831-6283
managed by
UT-BATTELLE, LLC
for the
US DEPARTMENT OF ENERGY
under contract DE-AC05-00OR22725
CONTENTS
LIST OF FIGURES
LIST OF TABLES
ACRONYMS
1.OVERVIEW
2.PEPEx Algorithm
2.1INTRODUCTION
2.2Step 1: Basic Information
2.3Step 2: Energy and production
2.3.1Units of Measurement
2.3.2Facility’s Energy and Production Data
2.3.3Site to Source conversion (optional)
2.4Step 3: Energy Use Systems
2.5Step 4: Energy Savings oppOrtunity
3.Results
3.1Annual Energy Use
3.2Potential Annual Energy Savings
3.3Suggested Next Steps
APPENDIX A. Energy Distribution by Industry
APPENDIX B. PEPEx Scorecard Questions and Scores
APPENDIX C. PEPEX Suggested Next Steps
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LIST OF FIGURES
Figure 1.The Excel Worksheet Tabs categorized based on their function.
LIST OF TABLES
Table 1. Ranges for PEPEx Scorecard Results
Table 2. Potential Percent of Savings for each End Use
Table A-1. Industry: All Manufacturing (NAICS 31-33)
Table A-2. Industry: Aluminum (NAICS 3313)
Table A-3. Industry: Cement (NAICS 327310)
Table A-4. Industry: Chemicals (NAICS 325)
Table A-5. Industry: Computers and Electronics (NAICS 334, 335)
Table A-6. Industry: Food and Beverage (NAICS 311-312)
Table A-7. Industry: Forest Products (NAICS 321, 322)
Table A-8. Industry: Foundries (NAICS 3315)
Table A-9. Industry: Glass (NAICS 3272, 327993)
Table A-10. Industry: Machinery (NAICS 333)
Table A-11. Industry: Fabricated Metals (NAICS 332)
Table A-12. Industry: Petroleum Refining (NAICS 324110)
Table A-13. Industry: Plastics (NAICS 326)
Table A-14. Industry: Iron and Steel (NAICS 3311, 3312)
Table A-15. Industry: Textiles (NAICS 313-316)
Table A-16. Industry: transportation Equipment (NAICS 336)
Table B-1. Combined Heat and Power Scorecard Question
Table B-2. Compressed Air Scorecard Questions
Table B-3. Process Cooling and Refrigeration Scorecard Questions
Table B-4.Process Heating Scorecard Questions
Table B-5. Pumps Scorecard Questions
Table B-6. Steam Generation Scorecard Questions
Table C-1. Suggested Next Steps
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ACRONYMS
PEPPlant Energy Profiler
PEPExPlant Energy ProfilerExcel
DOEDepartment of Energy
ORNLOak Ridge National Laboratory
MECSManufacturing Energy Consumption Survey
EIAEnergy Information Administration
CHPCombined Heat and Power
HVACHeating, Ventilation and Air-Conditioning
kWhKilowatt hour
MMBTUMillion Btu
HRSGHeat Recovery Steam Generator
FSATFan System Assessment Tool
PSATPump System Assessment Tool
CWSATChilled Water System Assessment Tool
PHSATProcess Heating System Assessment Tool
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1.OVERVIEW
This document outlines the underlying logic and computations performed by the Plant Energy Profiler Excel or PEPEx tool. The goal is to present the algorithm in plain text so that it can be reviewed and validated by subject matter experts, and for reference in any future design or upgrade efforts.
2.PEPEx Algorithm
2.1INTRODUCTION
The PEPEx tool consists of fourdata collection sheets (input sheets) which are used to estimate the amount of energy used to support the operation of a plant and potential energy savings opportunities. In the results sheet, the tool plots the current energy consumption (electric, natural gas, steam and other fuels) of the plant. The potential energy savings are also calculated based on user inputs. The sections below outline the data and scorecard values collected by PEPEx and how they are used for computation. Further, each step defined in this section corresponds to a input sheet that needs to be completed by the user.
Figure1.The Excel Worksheet Tabs categorized based on their function.
2.2Step 1: Basic Information
In the basic info sheet, PEPEx asks for plants contact information, plants' operating schedule and some general energy management questions. While a majority of these questions are for book-keeping purposes, the industry type and the energy management questions affect the results and play into the tools algorithm.
The type of industry selected by the user determines default energy use distribution values for step three, based on data from the latest EIA Manufacturing Energy Consumption Survey (MECS). See appendix A for the default breakdown of energy use by thesystem for each industry choice.
The general energy management scorecard evaluates the energy management steps that have been taken at the plant; including the energy management plan, appointment of an energy management team, and approach for determining theeconomic impact of energy efficient equipment. The answers to these questions affect the recommendations but do not affect the savings
2.3Step 2: Energy and production
The second input sheet in the PEPEx application is “Energy and Production”. The following section lays out the data defined in this section and how it is used by the tool.
2.3.1Units of Measurement
PEPEx allows the user to input the energy data for each fuel in their preferred unit, these units needs to be defined in the first section of this sheet. In order todisplay results for the various energy sources together and to calculate energy intensity, PEPEx converts all the input data to a common output unit. This output unit needs to be defined by the user in this section aswell.
2.3.2Facility’s Energy and Production Data
In this section, the total electricity, natural gas, steam and any other fuel provided to the plant is collected. For each energy stream, the user is asked to enter either the monthly or annual units purchased and associated cost. The user may choose to not enter the cost information in this section and can alternatively use the “Unit cost of Energy” below to provide this information. The energy consumption values gathered in this section are used to calculate the annual energy and the potential savings.
Along with the energy data, the production information for the plant is collected. This step is optional. Similar to energy the user can enter the production data by month or for the entire year. This section is optional, but if complete, the information is used to calculate energy intensity and associated graphs.
2.3.3Site to Source conversion (optional)
The user also has the option to input a source energy factor for each fuel used. Source Energy factor is used to calculate the source energy for each energy stream. Source energy incorporates all transmission, delivery and production losses associated with each energy stream.
The default source factor for each stream is provided, based on those used in Energy Star Portfolio Manager. The user may wish to make appropriate changes to this factor to account for losses associated with transmission, delivery, and production of each energy stream. PEPEx calculates all its results in terms of "site energy" unless explicitly stated.
2.4Step 3: Energy Use Systems
In this section, the percent of total annual energy use that each major system in the plant consumes is defined. Default values are set based on the industry selected in Step one: Basic Info, but the distribution profile can be edited by the user to provide a more custom view of the plant.
This section asks the user to select all of the energy use systems that are used in the plant and the associated primary and secondary fuel. The systems selected in this section determine which questions and scorecards will be needed in step four. The system choices that are shown in this step include:
- Combined Heat and Power
- Compressed Air
- Electrochemical Processes
- Fans and Blowers
- Industrial Facilities (Lighting, HVAC, and Facility Support)
- Materials Handling
- Materials Processing
- Process Cooling and Refrigeration
- Process heating
- Pumps
- Steam Generation Equipment
2.5Step 4: Energy Savings oppOrtunity
This sheet is used to characterize the potential energy saving opportunities for the various major systems in the plant. For each system, the user is asked to rank the energy saving opportunity level based on whether or not an energy savings assessment has been done on the system and how much effort has been put into conserving energy for that system. Data collected in this section affects recommended next steps and the magnitude of potential savings identified in the results section. If the energy savings opportunity for a system is ranked as “high”, a recommendation to perform a detailed system assessment at the site is provided in the suggested next steps section.
The user also has the option to use a scorecard to determine energy savings potential associated with a system by choosing the scorecard option from the drop-down list.
The scorecards are available for the following systems,
- Combined Heat and Power Scorecard
- Compressed Air Scorecard
- Process Cooling and Refrigeration Scorecard
- Process Heating Scorecard
- Pumps Scorecard
- Steam Generation Equipment Scorecard
For each system scorecard, the user may be asked questions about the components, hours of use, measurement and monitoring procedures, maintenance, etc. A full list of questions is shown in tables B.1 through B.6 of Appendix B.
The energy use systems questions are used to determine the level of opportunity to save energy. In each scorecard, the answer to each question is assigned a number value. The total for each scorecard is calculated and used to determine the energy savings opportunities for the system area. Refer to tables B.1 through B.6 in appendix B for the amount of points assigned to each answer. Section 3.2 provides a table that summarizes how the energy saving opportunity level for each system area is computed.
3.Results
PEPEx computes potential annual energy savings and suggested next steps, based on the answers provided in the scorecards, supplied energy, and energy use distribution data.
3.1Annual Energy Use
The total annual electricity, fuel, steam and other fuel is calculated in the results section. The total cost of the electricity, fuel, steam and other fuel is also calculated. The total energy consumption is calculated by converting the energy uses entered in Step 1: Energy and Production into the same unit and summing the inputs.
3.2Potential Annual Energy Savings
Potential energy savings is calculated based on the ranking given to energy use system and the industry selected in Step 1. Answers in Step 2: Energy Use Systems Scorecards and Step 3: Energy Savings Opportunities are assigned a number value. The total for each system is then calculated. Based on the total for the system, a ranking of high, medium, or low is assigned to the energy savings opportunity for that system. See tables B.1 through B.6 in Appendix B for the values assigned for each answer. The key for each system is shown below.
Table 1. Ranges for PEPEx Scorecard Results
Scorecard / Minimum Point Value / Maximum Point Value / RankingCompressed Air / 0 / 40 / High
Compressed Air / 40 / 80 / Medium
Compressed Air / 80 / 100 / Low
Process Cooling and Refrigeration / 0 / 40 / High
Process Cooling and Refrigeration / 40 / 85 / Medium
Process Cooling and Refrigeration / 85 / 100 / Low
Process Heating / 0 / 25 / High
Process Heating / 25 / 50 / Medium
Process Heating / 50 / 100 / Low
Pumps / 0 / 40 / High
Pumps / 40 / 80 / Medium
Pumps / 80 / 100 / Low
Combined heat and power (cogeneration) / 0 / 40 / High
Combined heat and power (cogeneration) / 40 / 80 / Medium
Combined heat and power (cogeneration) / 80 / 100 / Low
Steam Generation Equipment / 0 / 50 / High
Steam Generation Equipment / 50 / 80 / Medium
Steam Generation Equipment / 80 / 100 / Low
Each end use is assigned a ranking of high, medium, or low depending on the score. The ranking for each end use corresponds to a potential percentage of savings. Table 2 lists the percentage savings corresponding to each combination of end use and savings opportunity ranking. The potential percentage of savings is multiplied by the current energy use to determine the potential energy savings.
For example, consider a compressed air system that used 1,000 kWh of energy a year. If the opportunity to save energy in the system was ranked as high, the tool would estimate that the system could save 15% of their annual energy use corresponding to an annual savings of 150 kWh.
Table 2. Potential Percent of Savings for each End Use
End Use / High Savings Opportunity (%) / Medium Savings Opportunity (%) / Low Savings Opportunity (%)Combined heat and power (cogeneration) / 5 / 3 / 1
Compressed air / 20 / 15 / 5
Electrochemical Processes / 0 / 0 / 0
Fans and Blowers / 10 / 10 / 10
Industrial Facilities (Lighting, HVAC and Facility Support) / 15 / 15 / 15
Materials Handling / 0 / 0 / 0
Materials Processing / 0 / 0 / 0
Process cooling and refrigeration / 15 / 10 / 5
Process heating:
Aluminum and Alumina
Cement
EAF Steel
Foundries
Glass and Glass Products
Integrated Steel / 40 / 25 / 10
Process heating:
Chemicals and Allied Products
Fabricated Metal Products
Petroleum Refining / 25 / 15 / 7.5
Process heating (all others) / 15 / 10 / 5
Pumps / 15 / 10 / 10
Steam Generation Equipment / 20 / 15 / 5
3.3Suggested Next Steps
Suggested next steps are determined by the savings opportunity for the system. Each answer in the scorecards is assigned a number value. See tables B.1 through B.6 in Appendix B for the values assigned for each answer. The total from all the answers is calculated for each energy use system. Based on the total from the section, an energy savings opportunity ranking of high, medium, or low is assigned to the system. This ranking determines which recommendations will be shown in the suggested next steps section of the results. See Appendix C for the key that determines which recommendations will be shown given the ranking for the system.
Questions about the user’s current energy management practices are asked in the scorecards in steps 1 If the user states they are currently doing energy management practices that may show up as a recommendation, such as, measuring and monitoring their current energy use, then this suggestion would not show up in the recommendations section.
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APPENDIX A.Energy Distribution by Industry
Table A-1. Industry: All Manufacturing (NAICS 31-33)
End Use / % Electricity Usage / % Steam Usage / % Fuel UsageProcess Uses / Conventional Boilers / 3% / 0% / 17%
CHP/Cogeneration / 0% / 0% / 32%
Other Electricity Generation / 0% / 0% / 0%
Process Heating / 11% / 80% / 42%
Process Cooling and Refrigeration / 7% / 0% / 0%
Electro-Chemical Process / 8% / 0% / 0%
Pumps / 14% / 7% / 1%
Fans / 8% / 3% / 1%
Compressed Air / 9% / 0% / 0%
Materials Handling / 7% / 0% / 0%
Materials Processing / 13% / 0% / 0%
Other Machine Driven Systems / 2% / 1% / 0%
Other Process Uses / 1% / 1% / 2%
Nonprocess Uses / Facility HVAC / 9% / 8% / 4%
Facility Lighting / 7% / 0% / 0%
Other Facility Support / 2% / 0% / 0%
Onsite Transportation / 0% / 0% / 1%
Other Nonprocess Uses / 0% / 0% / 0%
100% / 100% / 100%
Table A-2. Industry: Aluminum (NAICS 3313)
End Use / % Electricity Usage / % Steam Usage / % Fuel UsageConventional Boilers / 0% / 0% / 3%
CHP/Cogeneration / 0% / 0% / 12%
Other Electricity Generation / 0% / 0% / 0%
Process Heating / 5% / 4% / 76%
Process Cooling and Refrigeration / 1% / 0% / 2%
Electro-Chemical Process / 78% / 0% / 0%
Pumps / 1% / 59% / 1%
Fans / 2% / 23% / 0%
Compressed Air / 2% / 0% / 0%
Materials Handling / 6% / 0% / 0%
Materials Processing / 2% / 0% / 0%
Other Machine Driven Systems / 0% / 9% / 0%
Other Process Uses / 0% / 0% / 1%
Facility HVAC / 1% / 6% / 3%
Facility Lighting / 2% / 0% / 0%
Other Facility Support / 1% / 0% / 1%
Onsite Transportation / 0% / 0% / 1%
Other Nonprocess Uses / 0% / 0% / 0%
100% / 100% / 100%
Table A-3. Industry: Cement (NAICS 327310)
End Use / % Electricity Usage / % Steam Usage / % Fuel UsageProcess Uses / Conventional Boilers / 0% / 0% / 0%
CHP/Cogeneration / 0% / 0% / 11%
Other Electricity Generation / 0% / 0% / 0%
Process Heating / 9% / 4% / 88%
Process Cooling and Refrigeration / 0% / 0% / 0%
Electro-Chemical Process / 0% / 0% / 0%
Pumps / 6% / 59% / 1%
Fans / 11% / 0%
Compressed Air / 11% / 0% / 0%
Materials Handling / 36% / 0% / 0%
Materials Processing / 10% / 0% / 0%
Other Machine Driven Systems / 1% / 9% / 0%
Other Process Uses / 2% / 0% / 0%
Nonprocess Uses / Facility HVAC / 7% / 6% / 0%
Facility Lighting / 4% / 0% / 0%
Other Facility Support / 2% / 0% / 0%
Onsite Transportation / 0% / 0% / 1%
Other Nonprocess Uses / 0% / 0% / 0%
100% / 100% / 100%
Table A-4. Industry: Chemicals (NAICS 325)
End Use / % Electricity Usage / % Steam Usage / % Fuel UsageConventional Boilers / 4% / 0% / 25%
CHP/Cogeneration / 0% / 0% / 44%
Other Electricity Generation / 0% / 0% / 0%
Process Heating / 5% / 86% / 22%
Process Cooling and Refrigeration / 8% / 0% / 1%
Electro-Chemical Process / 14% / 0% / 0%
Pumps / 16% / 7% / 2%
Fans / 7% / 3% / 1%
Compressed Air / 17% / 0% / 0%
Materials Handling / 1% / 0% / 0%
Materials Processing / 14% / 0% / 0%
Other Machine Driven Systems / 1% / 1% / 0%
Other Process Uses / 1% / 0% / 2%
Facility HVAC / 6% / 4% / 1%
Facility Lighting / 4% / 0% / 0%
Other Facility Support / 1% / 0% / 0%
Onsite Transportation / 0% / 0% / 0%
Other Nonprocess Uses / 0% / 0% / 0%
100% / 100% / 100%
Table A-5. Industry: Computers and Electronics (NAICS 334, 335)
End Use / % Electricity Usage / % Steam Usage / % Fuel UsageConventional Boilers / 1% / 0% / 31%
CHP/Cogeneration / 0% / 0% / 0%
Other Electricity Generation / 0% / 0% / 0%
Process Heating / 15% / 15% / 31%
Process Cooling and Refrigeration / 9% / 0% / 1%
Electro-Chemical Process / 1% / 0% / 0%
Pumps / 5% / 1% / 0%
Fans / 3% / 0% / 0%
Compressed Air / 4% / 0% / 0%
Materials Handling / 2% / 0% / 0%
Materials Processing / 7% / 0% / 0%
Other Machine Driven Systems / 5% / 0% / 0%
Other Process Uses / 6% / 0% / 2%
Facility HVAC / 24% / 84% / 30%
Facility Lighting / 12% / 0% / 0%
Other Facility Support / 6% / 0% / 0%
Onsite Transportation / 0% / 0% / 3%
Other Nonprocess Uses / 1% / 0% / 1%
100% / 100% / 100%
Table A-6. Industry: Food and Beverage (NAICS 311-312)
End Use / % Electricity Usage / % Steam Usage / % Fuel UsageConventional Boilers / 2% / 0% / 48%
CHP/Cogeneration / 0% / 0% / 18%
Other Electricity Generation / 0% / 0% / 0%
Process Heating / 6% / 78% / 25%
Process Cooling and Refrigeration / 26% / 0% / 0%
Electro-Chemical Process / 0% / 0% / 0%
Pumps / 11% / 3% / 1%
Fans / 5% / 1% / 0%
Compressed Air / 5% / 0% / 0%
Materials Handling / 4% / 0% / 0%
Materials Processing / 17% / 0% / 0%
Other Machine Driven Systems / 4% / 1% / 0%
Other Process Uses / 1% / 0% / 2%
Facility HVAC / 9% / 16% / 4%
Facility Lighting / 7% / 0% / 0%
Other Facility Support / 2% / 0% / 1%
Onsite Transportation / 0% / 0% / 0%
Other Nonprocess Uses / 0% / 0% / 0%
100% / 100% / 100%
Table A-7. Industry: Forest Products (NAICS 321, 322)
End Use / % Electricity Usage / % Steam Usage / % Fuel UsageConventional Boilers / 6% / 0% / 8%
CHP/Cogeneration / 0% / 0% / 79%
Other Electricity Generation / 0% / 0% / 0%
Process Heating / 5% / 85% / 10%
Process Cooling and Refrigeration / 2% / 0% / 0%
Electro-Chemical Process / 1% / 0% / 0%
Pumps / 24% / 5% / 1%
Fans / 15% / 2% / 0%
Compressed Air / 4% / 0% / 0%
Materials Handling / 6% / 0% / 0%
Materials Processing / 16% / 0% / 0%
Other Machine Driven Systems / 11% / 1% / 0%
Other Process Uses / 1% / 0% / 0%
Facility HVAC / 5% / 8% / 1%
Facility Lighting / 5% / 0% / 0%
Other Facility Support / 1% / 0% / 0%
Onsite Transportation / 0% / 0% / 1%
Other Nonprocess Uses / 0% / 0% / 0%
100% / 100% / 100%
Table A-8. Industry: Foundries (NAICS 3315)
End Use / % Electricity Usage / % Steam Usage / % Fuel UsageConventional Boilers / 0% / 0% / 3%
CHP/Cogeneration / 0% / 0% / 0%
Other Electricity Generation / 0% / 0% / 0%
Process Heating / 46% / 4% / 79%
Process Cooling and Refrigeration / 2% / 0% / 0%
Electro-Chemical Process / 4% / 0% / 0%
Pumps / 3% / 59% / 1%
Fans / 5% / 23% / 0%
Compressed Air / 5% / 0% / 0%
Materials Handling / 14% / 0% / 0%
Materials Processing / 3% / 0% / 0%
Other Machine Driven Systems / 0% / 9% / 0%
Other Process Uses / 2% / 0% / 1%
Facility HVAC / 9% / 6% / 13%
Facility Lighting / 5% / 0% / 0%
Other Facility Support / 2% / 0% / 1%
Onsite Transportation / 0% / 0% / 1%
Other Nonprocess Uses / 0% / 0% / 0%
100% / 100% / 100%
Table A-9. Industry: Glass (NAICS 3272, 327993)