Combined Heat and Power: A Clean, Local Energy Solution
DOE's Industrial Technologies Program (ITP) has identified combined heat and power (CHP) as one of the most important opportunities available today for increasing energy efficiency and reducing emissions. This article explains CHP technology uses and benefits, and ITP's effort to help the United States achieve a goal of 20% of CHP power generation by 2030.
The need for clean, efficient energy for the 21st century is moving a time-tested technology into the limelight. By providing on-site power generation, waste heat recovery, and system integration, combined heat and power (CHP) offers a realistic, near-term solution for exceptional energy efficiency and emission reduction.
As our nation faces growing electricity demand, volatile fuel costs, environmental concerns, and power reliability issues, DOE's Industrial Technologies Program (ITP) is working to boost CHP technologies to greater levels of efficiency and further expand the use of this clean energy solution. With proper technical and policy support, the goal of 20% generation capacity by 2030 can be achieved, saving approximately 5.8 quadrillion Btu per year, and avoiding 848 million metric tons of CO2 emissions. This is equivalent to removing more than 150 million cars off the road.
How CHP Works
Combined heat and power (CHP), or cogeneration, is the simultaneous production of electricity and heat from a single fuel source. A CHP system recovers the heat normally lost in electricity generation for use in cooling, heating, dehumidification, and other processes. Compared with separate generation of electricity and heat, CHP systems can operate at more than 80% efficiency.
CHP is not a single technology, but an integrated energy system that can be modified depending upon the needs of the energy end user. CHP can use a variety of fuels to provide reliable electricity, mechanical power, or thermal energy for industrial plants, universities, hospitals, or commercial buildings—wherever power is needed.
The diagram below compares the efficiency of a combined heat and power system with that of a conventional power plant. Learn more about how CHP works by visiting ITP's Combined Heat and Power Basics Web site.
Benefits for Peak Performance
Compared with separate heat and power production, combined heat and power systems provide many benefits, including:
- Energy efficiency: CHP systems recycle waste energy and use it for heating and cooling; enhance fuel use efficiency; and increase the benefit to the customer from each cubic foot of natural gas or propane consumed.
- Emissions reduction: Efficient CHP technologies decrease emissions of pollutants and greenhouse gases. What's more, CHP can use clean, renewable fuels such as biomass or biogas to provide electrical and thermal energy.
- Energy reliability and quality: CHP can operate in parallel with the grid to enhance power reliability and support operations, or supply onsite generating capacity. CHP technologies deliver the high-quality power required by computer systems and sensitive manufacturing processes.
- Energy security: CHP systems can operate independently of the grid to sustain critical services such as health care, communications, shelter, and public safety, after disasters.
- Economic development: CHP systems directly relieve grid congestion, reduce or eliminate power purchases, and avoid the need to construct new power plants. In the case of alternate fuels, CHP systems enable the use of local energy resources and support high-tech manufacturing industries.
- Job creation: Further development of and investment in CHP technologies will generate new jobs for highly skilled, technical workers, and boost local economies.
U.S. Combined Heat and Power in Operation
Some of the following documents are available as Adobe Acrobat PDFs.
- ITP's Distributed Energy Web site
- Combined Heat and Power: Effective Energy Solutions for a Sustainable Future (PDF 2.5 MB)
- CHP Resource Guide (PDF 871 KB)
- CHP Regional Application Centers
- CHP Software Tool for Gas Turbine-Driven Systems (PDF 1.3 MB)
- CHP Installation Database
- CHP Permitting and Regulatory Database
- EPA's State and Federal Incentives Funding Database
Currently, there are approximately 3,500 CHP sites in the United States, with a generating capacity of 85 GW or 9% of U.S. total capacity. This local, clean power generation is reducing annual fuel use by 1.9 quadrillion Btu and offsetting 248 million metric tons of CO2 emissions—equal to removing 45 million cars from the road.
Combined heat and power applications span industrial, commercial, and residential market sectors across all 50 states. Find information on CHP installations in your area by using the DOE-supported CHP Installation Database, the primary source for tracking CHP sites and market developments. The database provides details for each site on the facility, application, prime mover, capacity, and fuel type.
Breaking Down Barriers
Despite its proven benefits, a number of hurdles must be overcome to realize the full potential of CHP in the marketplace. Technical, regulatory, policy, and institutional barriers persist, despite successes at the state and regional level and recent federal legislation to boost tax credits for CHP. Read a summary (PDF 116 KB) of the latest CHP federal tax incentives.
ITP is committed to helping our nation overcome these barriers by working collaboratively with U.S. industry and other stakeholders to invest in significant technology improvements, and to transform the market at the federal, state, and regional levels. Ongoing efforts include:
- Increase CHP awareness through DOE's eight CHP Regional Application Centers, which serve as clearinghouses for CHP information and identify and implement regional CHP projects. The centers' educational outreach and technical assistance to end-user customers and state policy-makers are instrumental in helping to transform the market for CHP. To date, the CHP Regional Application Centers have assisted in the installation of 350 CHP projects around the country. Read the full story.
- Develop more efficient CHP components, such as advanced turbines, reciprocating engines, and thermally activated technologies, as well as integrated energy systems for new markets at commercial and small industrial facilities. Read about ITP's R&D to develop advanced reciprocating engine systems (PDF 241 KB).
- Support development of technologies through solicitations to encourage R&D of conventional CHP technologies, as well as those that use alternate fuels. In 2008, DOE issued two separate solicitations for these technology options, which awarded a total of $39 million to selected projects. Read details on the selected alternate fuel and combined heat and power projects.
- Reinforce partnerships with industry stakeholders, national laboratories, and other federal agencies to develop and deploy CHP. Current partners include:
- Environmental Protection Agency
- Federal Energy Management Program
- New York State Energy Research and Development Authority
- U.S. Clean Heat and Power Association
- World Alliance for Decentralized Energy
- American Council for an Energy Efficient Economy
- Northeast-Midwest Institute
- International District Energy Association.
These activities will help to expand the adoption of clean, efficient CHP technologies as a major source of electrical, mechanical, and thermal energy for the United States.
As ITP Program Manager Douglas Kaempf explains,"CHP represents a great near-term opportunity to save energy, reduce carbon emissions, and improve local economies. ITP is taking a lead role in enabling CHP to reach its potential."
For more information about ITP's CHP Program, contact Bob Gemmer.
CHP Regional Application Centers: Paving the Way for Combined Heat and Power
The U.S. Department of Energy's eight CHP Regional Application Centers are key channels for expanding the U.S. market for combined heat and power (CHP). By promoting CHP technologies and practices, serving as clearinghouses for local and regional CHP resources, and working with state policymakers to address barriers, the centers help pave the way to widespread deployment.
Combined heat and power (CHP) has been identified as one of the top solutions for improving industrial energy efficiency and impacting climate change. However, use of CHP is not optimized because of the need for application and project development assistance, lack of end-user and policymaker knowledge, and utility regulation barriers.
To address these issues and promote use of innovative CHP technologies, DOE established CHP Regional Application Centers (RACs) throughout the United States. The core mission of the RACs is to:
- Inform prospective CHP users on the benefits, business model, and resources available for their specific application. These efforts help facilitate CHP project viability through target market workshops, conferences, and Web sites.
- Support CHP project development with technical and financial analysis and assistance on project feasibility studies, permitting issues, and assessment of applicable tariffs/rates.
- Promote CHP as an effective clean energy policy solution to state policy-makers and regulators, and to work with this audience to eliminate barriers that prevent the widespread adoption of CHP.
Local and Regional Resource for Industry
Ethan Allen Success Story
The Ethan Allen Furniture Factory in Beecher Falls, Vermont, was struggling to stay in operation because of its high energy costs. This world-famous plant began in 1896 as the original Ethan Allen factory and employs 500 local workers. The Northeast CHP Regional Application Center stepped in to help to explore the possibility of incorporating combined heat and power for energy savings. The RAC staff recommended replacing the factory's steam engine with a steam turbine, using a biomass-fired boiler, which could save the factory 10% of its yearly energy costs with a 3-year payback. The factory owners implemented the recommendation. With the support and joint funding from the states of Vermont and New Hampshire and the Vermont Electric Cooperative utility, the Ethan Allen Furniture Factory is keeping manufacturing operations in New England. Details.
The eight CHP Regional Application Centers serve the Gulf Coast, Intermountain, Mid-Atlantic, Midwest, Northeast, Northwest, Pacific, and Southeast regions. The local and regional nature of the RACs allows them to address the wide range of market and regulatory requirements for CHP systems that vary by state and utility region. The RACs are able to respond to their customers' individual needs with specific knowledge on the most relevant issues for local CHP project development.
The RACs are led through a collaborative partnership of ten universities, two research organizations, and one non-profit organization. To optimize efforts of all of the centers, meetings and conference calls are held to ensure that efforts are not duplicated, and that ideas are leveraged across the country.
This strategic approach has resulted in proven successes. The RACs have coordinated more than 120 end-user focused workshops, informing more than 9,000 attendees about the benefits of CHP for their applications. In addition, education of state regulators and policymakers on CHP and clean energy benefits has resulted in new incentive programs, inclusion of CHP in energy efficiency and renewable portfolio standards, improved interconnection standards, and more favorable standby policies in many states.
The CHP Regional Application Centers have supported more than 350 projects representing more than 1.3 GWs of CHP installed or in development. Implementation of these projects has offset more than 7.7 million tons of CO2 emissions, which is equivalent to planting 1.9 million acres of trees and removing 1.2 million cars from the road. As a result of energy cost savings identified in one assessment, a 100-year old company that was considering closing down their factory and moving to another location was able to remain in operation in their home state (see sidebar).
CHP Regional Application Centers and Contact Information
|Region||Information and Key Contacts|
|Gulf Coast||Daniel Bullock
Houston Advanced Research Center
University of Maryland
UIC Energy Resources Center
Pace Energy and Climate Center
Washington State University
University of California, Berkeley
Mississippi State University
North Carolina State University
To learn more about the Regional Application Centers, please contact:
Power Equipment Associates
New Report Highlights Jobs, Emission-Savings Benefits of Combined Heat and Power
To increase awareness about clean energy solutions for the nation, the U.S. Department of Energy's Industrial Technologies Program (ITP) and Oak Ridge National Laboratory (ORNL) recently released Combined Heat and Power: Effective Energy Solutions for a Sustainable Future (PDF 2.5 MB). Download Adobe Reader. This comprehensive report highlights combined heat and power (CHP) as a realistic solution to enhance energy efficiency, ensure environmental quality, promote economic growth, and foster a robust energy infrastructure in the United States. It also discusses current opportunities and challenges to widespread national CHP deployment, and sets the stage for future policy dialogue aimed at promoting this clean energy solution.
The report answers the question: "What if 20% of U.S. generating capacity came from CHP?" and presents technology, market, and policy options to achieve this goal by 2030. If this goal were met, projected benefits would include:
- A 60% reduction of the projected increase in carbon dioxide (CO2) emissions by 2030—the equivalent of removing 154 million cars from the road
- Fuel savings of 5.3 quadrillion Btu annually—the equivalent of nearly half the total energy currently consumed by U.S. households
- Economically viable application throughout the nation in large and small industrial facilities, commercial buildings, multi-family and single-family housing, institutional facilities, and campuses
- Creation of 1 million new highly-skilled, competitive "green-collar" jobs through 2030
- Approximately $234 billion in new investments throughout the United States.
Potential Savings of 20% of CHP Generation capacity by 2030
240 Gigawatts (equal to 200-300 coal-fired power plants)
5 quadrillion Btu of energy savings
848 million metric tons of annual CO2 emissions reduction
Combined heat and power, also known as cogeneration, is the concurrent production and use of electricity or mechanical power and thermal energy. CHP includes a suite of technologies that can use a variety of fuels to generate electricity or power at the point of use, allowing normally lost heat to be recovered to provide needed heating or cooling. Using CHP today, the United States already avoids more than 1.9 quadrillion Btu of fuel consumption and annual CO2 emissions—equivalent to removing more than 45 million cars from the road.
The report is a joint effort between ITP and ORNL with substantial input and review by a range of industry, association, and non-governmental stakeholders. To view the report and to learn more about ITP's CHP activities, visit the Industrial Distributed Energy Web site.
Combined Heat and Power in Action: Demonstration Projects Showcase Technologies
Recognizing combined heat and power (CHP) as a realistic, near-term option for reducing energy use and emissions, the U.S. Department of Energy (DOE) has actively supported cost-shared technology R&D and demonstration projects during the past 10 years—contributing to 85 GW of CHP power in more than 3,500 facilities in the United States. This article showcases four successful DOE cost-shared CHP demonstration projects using a variety of technologies, and illustrates the broad applicability of CHP across industrial, commercial, and institutional facilities.
DOE's technology development focuses on gas-fired advanced reciprocating engine systems, industrial gas turbines, microturbines, fuel cells, and thermally-activated technologies. DOE has also focused on integrated energy systems (IES)—combining power generation and heat recovery technologies to develop packaged and modular 'plug and play' systems. The following case studies illustrate some of these technologies in action.
The Verizon Telecommunications Switching Center in Garden City, New York, is a 292,000 square foot building that houses 900 employees and provides telecommunications services to more than 35,000 customers on Long Island. The facility is the largest fuel-cell-based CHP installation providing energy service to a Verizon facility. It uses seven 200 kW, natural-gas-fired fuel cells paralleled with the grid, three reciprocating engines, two 70-ton absorption chillers, and a heat recovery steam generator (HRSG) to provide power, cooling, and heating to the facility.
The CHP system became operational in June 2005. A unique feature of this system is that the fuel cells and reciprocating engines are used to supply energy to the facility at different times and outputs depending on the facility's energy needs. For example, the system recovers high-grade waste heat from the fuel cells for use by the two absorption chillers to cool the central office in the summer. During the winter months, the same waste heat is used by the HRSG for heating to supplement existing boilers.
On an annual basis, this combination of CHP sources provides 16 MMBtu of useful thermal energy and 38,000 Btu of useful electricity, and offsets 11.1 million pounds of CO2. With an annual energy savings of $0.5 million, and implementation costs of approximately $13 million, the payback period is about 10 years.
Verizon hopes to replicate this CHP system within their portfolio of central offices, using lessons learned. According to Jeremy Metz, Energy Team Leader, Verizon Strategic Sourcing, the company hopes to "learn all about operating and maintaining fuel cells now so when their prices come down, we can install them efficiently and cost-effectively."
Download the Verizon Switching Center case study (PDF 384 KB).
Arrow Linen is an industrial laundry facility located near Prospect Park in Brooklyn, New York. The facility uses large quantities of hot water, electricity, and steam to clean uniforms, table linens, and other items for restaurant and institutional customers. In April 2003, two natural-gas-fired 150kW reciprocating engines were installed to produce electricity and preheat hot water. The engines run six days per week for 10 to 14 hours each day and are automatically controlled to match their electrical output to the building load so that no power is exported to the utility. The system provides approximately 75% of the required electricity to run the facility.
Because the engines operate only when the process is active, the CHP system achieves a consistently high efficiency of more than 80%. Additionally, this CHP installation uses nearly all the available heat recovered to meet process hot water loads (2,000 MBtu per hour), and achieved monthly cost savings of $10,000 and annual utility savings of $120,000 with a simple payback of 3 years.
Fort Bragg in Fayetteville, North Carolina, is one of the world's largest U.S. Army installations. The Army post houses the 82nd Airborne Division and the XVIII Airborne Corps, along with Army Special Operations Command and other rapid deployment units. Thanks to development of the system through DOE's Integrated Energy System (IES) program and financing from an energy savings performance contract (ESPC) with Honeywell, Fort Bragg installed a CHP generation system at the 82nd central heating plant in June 2004.
The innovative CHP system at Fort Bragg is used to drive the plant's heating and cooling services for about 50 barracks and buildings. It directs waste heat from a solar 5 MW gas turbine generator to a heat recovery steam generator to produce hot water for heating. During summer, waste heat from the turbine is used to drive an absorption chiller to produce 1,000 tons of chilled water. Additionally, the system has improved fuel efficiency of 33% to 45% to more than 70%, and is expected to save the base about $1.8 million per year. Total energy costs have been reduced by more than 25%.
This CHP installation is also unique in that Fort Bragg operates it with optimization software to determine the best operating strategy on an hourly basis. The software is part of the plant's control system and considers electric, heating, and cooling loads; fuel prices; the electric grid; equipment performance; and current weather data to determine how to meet these loads using the CHP equipment, grid power, and supplementary heating and cooling equipment.
Learn more (PDF 96 KB).
Ronald Reagan Presidential Library and Museum and Air Force One Pavilion
The 100,000 square foot Ronald Reagan Presidential Library and Museum in Simi Valley, California, is located adjacent to the 95,000 square foot Air Force One Pavilion (opened in October 2005), which houses a Boeing 707, Marine One helicopter, Irish pub, and special exhibits. A cogeneration system, including the use of 16 60 kW microturbines, generates 95% of the buildings' electricity and captures waste heat to operate absorption chillers for cooling.
The 16 microturbine units are ideal for the Ronald Reagan facility as they can be run at full load and still allow for ramping up or down as needed per various cooling and power requirements throughout the day. Additionally, because the library has environmental constraints in spaces that house important historical documents, those rooms must be kept at a steady temperature and humidity level.
The system at the library includes three UTC PureComfort™ cooling, heat, and power packages—each with four 60 kW microturbines and one 129-ton Carrier absorption chiller. The direct exhaust-fired chillers use thermal energy from the microturbines to create 387 tons of refrigeration for cooling both the Library and the Pavilion. The exhaust from four PureThermal™ 60 kW turbines, which produce 960 kW, raises the temperature of water to heat the Pavilion during winter months. This system operates at 80% efficiency, reduces greenhouse gases by about 40% and NOx emissions by 90% from grid generated power, and has been estimated to save approximately $300,000 in annual operating costs.
The UTC Pure Comfort System was developed with support from DOE. The system at the Ronald Reagan Presidential Library is one of more than 20 replicable systems that have been installed since the design and demonstration of the initial system.
Download the case study to learn more (PDF 1.3 MB).
Visit the Web sites below to find additional information on CHP systems, technologies, and installations.
- Combined Heat and Power Installation Database: State-specific CHP units
- Regional Application Centers: CHP deployment services, technologies descriptions, installation and contacts databases, target market workshops and presentations, CHP installation tools, and installation documentation.
Maximize System Efficiency with Proper Insulation
Properly designed insulation and refractories for industrial systems can mean big energy and cost savings for manufacturing companies. Dr. Arvind Thekdi, our featured U.S. Department of Energy (DOE) Energy Expert, regularly conducts Save Energy Now energy assessments, and is proficient in helping companies realize energy savings through effective insulation practices. In this issue of Energy Matters, Dr. Thekdi answers questions about calculating heat loss, types of insulation materials, and methods for maximizing system efficiency.
What role does insulation and refractory design play in energy savings?
The terms "refractories" and "insulation" refer to a large family of inorganic, nonmetallic materials used primarily to reduce heat loss or for thermal insulation. Insulation and refractories, individually or in combination, are used to contain heat in all applications where heat is generated, transferred, transmitted, or recovered. Typical industrial applications include boilers, steam and hot fluid piping, furnaces, ovens, heaters, and storage tanks.
Insulating materials include those with low-thermal conductivity that divide an air space into very small pockets, thereby minimizing solid and gas conduction and radiation, and, for most applications, eliminating convection. Properly designed refractory and insulation systems reduce heat loss, conserve energy by reducing heat storage, maintain desired process temperatures, assist in heat transfer, and safely contain process atmosphere, such as flammable, toxic, or hazardous gases, vapors, or liquids.
How much energy can be saved through use of proper refractory and insulating materials?
All insulated surfaces lose some heat. The heat loss depends on a number of factors such as the heating system or heat source temperature, selection and thickness of insulation used, and exposure of insulated surfaces to ambient conditions. Heating systems may lose 2% to 5% of the total heat input for the heating system through insulated surfaces. It is not feasible or always advisable to eliminate all insulation-related heat loss, but it is possible to reduce these losses by 10% to 25%. To achieve this, plant personnel must:
- Review process requirements
- Know available and applicable insulation materials
- Select materials to meet the process requirements
- Properly design, install, and precondition insulation systems during start-up
- Properly operate the equipment to avoid damage to the insulation
- Perform periodic maintenance, repairs, and replacement of the insulation.
How do I calculate heat loss?
For existing furnaces, ovens, or heating systems it is not necessary to perform detailed heat transfer analysis to calculate heat loss from a system; it is only necessary to measure the outside surface temperature. The heat loss calculations require measurement of surface temperature and information on conditions such as ambient temperature, wind velocity, orientation of the surface (vertical, horizontal facing upwards or downwards, etc.) and condition or emissivity (shiny vs. black or rusted) of the surface. Figure 1 shows values of heat loss per square foot of the heating system outside surface for a vertical surface with emissivity of 0.9 and wind velocity of zero miles per hour (indoor installation). This graph should be used as a general guide because wall heat loss depends on a number of factors.
Note that the heat loss calculated using Figure 1 or any other method should be corrected for the "available heat" for a heating system, particularly in a fired system that uses combustion of fuels such as natural gas. The available heat is the amount of heat that remains in the furnace after accounting or subtracting heat contained in flue (exhaust) gases leaving the heating system. The available heat for a fuel-fired heating system can be calculated by using graphs provided in Reference 1 (PDF 2.4 MB) or other industrial combustion books. The actual heat required and energy cost to compensate for the calculated wall heat losses could be considerably higher than the cost of energy calculated without correcting the heat loss calculated for the available heat.
Example: Calculating Savings by Reducing Wall Heat Loss of an Industrial Furnace
Consider the case of a natural gas-fired furnace located in these ambient conditions: little wind and 75°F, with total outside surface area of 500 square feet and surface temperature of 200°F.
From Figure 1, we can estimate the surface heat loss to be 275 Btu/square foot or (275 x 500=) 137,500 Btu/hr. The furnace flue gases are discharged at 1,400°F with 5% oxygen in exhaust gases. The available heat for this system is approximately 55% as calculated by using graphs given in Reference 1 (PDF 2.4 MB) or other industrial combustion books.
In this case, it is necessary to supply (137,500/0.55=) 250,000 Btu/hr to the combustion system. Reduction of surface temperature to 150°F by additional or alternate insulation would reduce heat loss by 35% or approximately 90,000 Btu/hr. For annual operation of 8,000 hours/year and natural gas costs of $10 per MMBtu, the savings would be more than $7,200 per year.
The heating system insulation design should consider the lowest possible and economically justified surface temperature using the economic considerations discussed above.
What types of refractories and insulation materials are available?
Refractories are classified by chemical composition or physical properties. These include silica, alumina-silica, high alumina, basic, and insulating. Most high-temperature refractories, such as firebricks, are high-density (>120 lb/ft3), and offer excellent resistance in challenging operating environments, such as containment of high-temperature slags with different chemical compositions, fumes, dust, and gases. Insulating refractories have lower densities (50 to 70 lb/ft3) and provide insulating properties while offering resistance to corrosion and chemical reactions in a less challenging operating environment.
The three basic types of insulating materials for industrial use are:
- Thin (less than 20 micrometers), low-density (less than 12 lb/ft3) fibers made from organic or inorganic materials
- Cellular material in closed or open cell form made of organic or inorganic material
- Flaked or granular inorganic materials bonded in the desired form.
In most cases, glass (silica), mineral wool, high alumina, mulite, or zirconium are the base materials and can be used to temperatures as high as 2,900°F. See the table below for a list of insulating materials, along with values of range of densities in terms of lbs/ft3 of dry material and range of thermal conductivities at 100°F. Exact values of the properties can be obtained from the suppliers. In general, lower density materials offer lower thermal conductivity or higher resistance to heat flow and store less heat compared to higher-density insulating or refractory materials.
Material for Insulated Heating Systems
Thermal conductivity at 100°F (Btu/hr-ft/°F)
|Carbon steel (0-500°F)||26.363||480.00|
|Rock (mineral) wool (0-1,200°F)||0.021||9.25|
|Ceramic blanket-4 pcf density (300-2,000°F)||0.009||4.00|
|Merchantable ceramic board (200-1,800°F)||0.019||14 to 20|
|Ceramic fiber board (300-2,300°F)||0.043||16 to 28|
|Ceramic fiber block (300-2,400°F)||0.025||8 to 11|
|Low density castable (300-2,200°F)||0.149||48 to 65|
|High density castable (300-2,600°F)||0.429||95 to 140|
|Low temp. insulating firebrick (300-2,300°F)||0.065||38 to 44|
|High temp. insulating firebrick (300-2,800°F)||0.182||48 to 82|
|High density firebrick (300-3,000°F)||2.288||180 to 190|
With the exception of certain high-density materials, thermal conductivity of the insulation generally increases significantly as temperature increases. Figure 2 shows relative thermal conductivity values of commonly used refractories and insulating materials. Note that these values are relative to thermal conductivity of the material at 100°F. Actual values of the thermal conductivity should be obtained from the supplier. Consider temperature of the refractory and appropriate value of thermal conductivity to estimate accurate value of heat loss.
What should I keep in mind when selecting refractories and insulation?
Proper design and installation of refractories and insulation are important for a system's performance and life and the overall economics of plant operation and profits. Consider the following four factors when selecting insulation materials and designing insulation systems:
- Thermal performance: This includes temperature limit; melting or fusion temperature; thermal conductivity that represents insulation capability; heat capacity or storage; thermal expansion; and thermal shock (spalling) resistance.
- Physical properties: These include density or porosity; abrasion; wear and erosion resistance; electrical resistivity for use in electric heating; mechanical strength; and other structural properties at high temperatures.
- Chemical considerations: These include uniformity of composition; reactions between base materials and operating environment such as gases, liquids or solids in contact with the refractory or insulating materials; and volatilization of the constituents or binding agents, corrosion, chemical attack, or diffusion and reactions with the product.
- Economics: This includes initial cost of insulation; installation cost (labor and materials); maintenance and repair; and replacement costs.
Most applications require use of more than one type of insulating material. All major suppliers offer guidelines and help in application and installation of insulation systems. In some cases, special tools and techniques are developed, and personnel must be trained for proper installation work.
What tools and methods are available for design and selection of insulating systems?
When selecting proper insulation thickness, consider the technical factors mentioned above along with economic factors such as energy cost savings and insulation system costs. Cost of insulation is almost proportional to the thickness, however, the rate of energy savings (savings with additional increase in insulation thickness) decreases as the thickness increases. Hence, there is an optimum value of insulation thickness for any application that gives the minimum payback period.
Figure 3 shows a qualitative example of variation in the cost of insulation, energy cost savings and payback period for a typical industrial insulation system. The savings are directly related to reduction in heat loss or energy cost savings, therefore, the optimum thickness will be directly affected by the energy cost. Most suppliers have developed "rules of thumb" for applicable insulation thickness based on a certain energy costs. Users should always ask for explanation of such rules because they may not necessarily give you the optimum values when energy costs rise substantially.
The cost of an insulation material relates to its temperature capability. Hence, insulation and refractory systems are designed to include several layers of different materials that offer optimum economic performance.
In some cases, the most economical thickness may not meet regulatory requirements for the safety of personnel and property, and appropriate design and materials should be used. In other cases, thickness may be reduced when there is a danger of exceeding the limiting refractory or insulating temperature.
A number of tools and design methods are available for selecting the most economical or appropriate refractories or insulation:
- 3E Plus® software, developed jointly by DOE's Industrial Technologies Program and the North American Insulation Manufacturer's Association (NAIMA), can be used to calculate and select the insulation thickness for a variety of conditions.
- The Process Heating Assessment and Survey Tool (PHAST) can be used for preliminary selection of insulating and refractory materials for high temperature furnaces.
- Several insulating material suppliers use their own software programs to design insulation systems for a given application using their own materials with more accurate values of thermal properties. These programs allow users to select a number of combinations of the available materials and calculate heat losses, surface temperature, and heat storage for the selected system.
- Improving Process Heating System Performance: A Sourcebook for Industry, Second Edition (PDF 2.4 MB)
- ITP BestPractices process heating system tip sheets
- Improving Steam System Performance: A Sourcebook for Industry (PDF 1.3 MB)
- ITP BestPractices steam system tip sheets.
Is Combined Heat and Power Right for Your Facility?
Are you thinking of installing a combined heat and power (CHP) system in your facility? Considering the complexities of adding a CHP system to your plant, planning for your installation requires significant time, effort, and investment. To help you get started, DOE's Industrial Technologies Program has developed the following steps to help you to determine if CHP is feasible for your site.
STEP 1: Walk-through Analysis
To begin the screening analysis, you will first need to collect data describing your plant's energy use, and operating and site conditions. Once that is completed, use the simple screening tool below to help you decide whether a detailed analysis is appropriate.
STEP 2: Feasibility Analysis
If the walk-through analysis gives you the thumbs-up, the next step is a screening analysis that considers more specific details, including the following:
- Detailed electric tariffs (retail service rates, partial service rates, standby/back-up rates, transmission and distribution tariffs)
- Fuel availability and price
- Capital budget
- Operating modes (baseload, thermal following, electric following)
- Grid interconnection requirements and costs
- Environmental permitting requirements and costs
- Project structure and development costs (insurance, administrative and management fees, financing.
For help with your feasibility analysis, consider one of the CHP software tools (PDF 3 MB) listed in this survey of available tools.
STEP 3: Preliminary Design
A positive feasibility analysis should lead to a more thorough evaluation that will provide enough information to make a decision, and consider the following factors:
- Analysis of hourly energy requirements and costs
- System part load performance
- System design and preliminary costs
- Return on investment/payback analysis
- Analysis of existing CHP systems.
STEP 4: Detailed Design
If the preliminary design evaluation is favorable, specification for bids would then be prepared for detailed project design and development.
Recognizing Companies that Save Energy Now
Three hundred U.S. manufacturers acknowledged as champions of energy efficiency are not only benefiting from energy and cost savings in their operations, but also serving as examples for the entire industrial community. This article describes ITP's Save Energy Now recognition program for companies who meet efficiency goals, and explains how your company can also be recognized for energy-saving efforts.
The U. S. Department of Energy's Industrial Technologies Program (ITP) established Save Energy Now recognition awards to reward innovative companies for actively pursuing energy-saving opportunities identified through an energy assessment. Since Save Energy Now began in 2007, ITP has recognized 300 U.S. manufacturers who have achieved more than $110 million in cost savings and 16.7 trillion Btu in total energy savings—enough energy to heat more than 330,000 single-family homes annually!
The individual plants and companies that are recognized annually are industry leaders who are investing in the sustainability of their facilities while taking advantage of the benefits of energy and cost savings. They not only reduce industrial energy use and carbon emissions in their facilities, but also serve as powerful examples to the entire manufacturing sector.
These winners play a key role in the success of Save Energy Now, which helps U.S. manufacturers identify ways to reduce energy use in key industrial systems. Between 2006 and 2008, Save Energy Now completed 1,900 energy assessments, which have identified more than $1 billion in potential cost savings and accrued $173 million in actual savings. The 300 awardees to date have contributed more than 60% of the implemented savings from the program and continue to build on their assessment recommendations and replicate these throughout their companies. View listings of the award recipients.
How Do Companies Qualify?
Types of Awards
ITP recognizes companies that have implemented energy-saving opportunities identified through a Save Energy Now energy assessment. Award categories include:
Energy Saver: More than 75,000 MMBtu total energy savings or more than 7.5% total energy savings.
Energy Champion Plant: More than 250,000 MMBtu total energy savings or more than 15% total energy savings.
Energy Champion Team: More than 10% total energy savings in the original plant and replication in two or more additional plants.
Visit the Eligibility Guidelines and Process Web site for information on award criteria.
Plants and companies qualify for an award by participating in a Save Energy Now energy assessment, implementing recommendations found during the assessment, and reporting their progress on schedule. All participants who meet the criteria are eligible to be selected for an Energy Saver or Energy Champion award according to the amount of energy savings implemented (see sidebar).
Once ITP determines that a plant has met the qualifying criteria based on the submitted progress reports, they are notified that they are eligible for an award. After the award is accepted, the company is publicly recognized, presented a trophy at a major industry meeting or ITP event, and listed on the Save Energy Now Web site. In addition to an award, the company receives access to an online recognition packet that includes logos and a customizable banner to help them publicize their success throughout the company and in their corporate communications.
Honoring Leaders in Energy Efficiency
The award events are conducted at national industry meetings as well as state and local energy events. ITP attempts to recognize awardees amongst their peers and chooses a variety of events throughout the country to reach as many winners as possible. Some recent award venues include:
- Grocery Manufacturers Association Sustainability Summit – Washington, DC
- IEEE Industrial Energy Efficiency Workshop – Baltimore, MD
- Industrial Energy Technology Conference – New Orleans, LA
- Manufacturers Association of Florida Annual Summit – Jacksonville, FL
- Michigan Energy Conference – Big Rapids, MI
- North Carolina Sustainable Energy Conference – Raleigh, NC
- Northwest Food Manufacturing and Packaging Expo – Portland, OR
- World Energy Engineering Congress – Washington, DC.
Public recognition of these U.S. manufacturers provides an incentive for energy-saving efforts and publicizes the real-world sustainability and competitive benefits of energy efficiency. The award winners often publish their details of their award in the company newsletter and conduct internal award ceremonies within their plants. These companies find value in the awards through both internal and external marketing along with acknowledgement of their efforts by DOE.
Acknowledging Current and Future Success
The Save Energy Now award winners are shining examples of the energy and cost savings that can be achieved through engineering and management innovation and a commitment to sustainability. These plants and companies are the major success stories of Save Energy Now; ITP hopes to recognize many more companies in the future.
Learn more about the Save Energy Now recognition awards.
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