Research proposal: Thermoelectric cooling in electric vehicles KristopherKerames
This research proposal describes the theory behind thermoelectric cooling (TEC) in the context of electric vehicle thermal management systems, and describes the experimental setup and error analysis required to study TEC in that context.
Active Thermal Management Systems in Electric VehiclesAutomotive IQ
The goal of all thermal management is to deliver a battery pack that functions at an optimum average temperature with even temperature distribution across all cells. Moreover, it must be lightweight, low cost, easy packaged and compatible too. Active thermal management systems offer a wide range of advantages for electric vehicle batteries. But is it actually better than passive systems?
Read more about the topic on the article’s second part on thermal management systems in electric vehicles here: http://bit.ly/Article_ActiveThermalmanagementsystems
Phase Change Materials(PCM) based solar refrigerationVishvesh Shah
Topics to be Covered
Refrigeration Using solar Energy
Introduction
Solar PV Based Refrigeration
Solar Absorption Refrigeration
Energy Storage Systems
Battery
Phase Change Materials
Solar Refrigeration System Model Studies
Solar powered refrigerator with Thermal Energy Storage
Solar Direct Drive Refrigerator for Vaccine Storage
Research proposal: Thermoelectric cooling in electric vehicles KristopherKerames
This research proposal describes the theory behind thermoelectric cooling (TEC) in the context of electric vehicle thermal management systems, and describes the experimental setup and error analysis required to study TEC in that context.
Active Thermal Management Systems in Electric VehiclesAutomotive IQ
The goal of all thermal management is to deliver a battery pack that functions at an optimum average temperature with even temperature distribution across all cells. Moreover, it must be lightweight, low cost, easy packaged and compatible too. Active thermal management systems offer a wide range of advantages for electric vehicle batteries. But is it actually better than passive systems?
Read more about the topic on the article’s second part on thermal management systems in electric vehicles here: http://bit.ly/Article_ActiveThermalmanagementsystems
Phase Change Materials(PCM) based solar refrigerationVishvesh Shah
Topics to be Covered
Refrigeration Using solar Energy
Introduction
Solar PV Based Refrigeration
Solar Absorption Refrigeration
Energy Storage Systems
Battery
Phase Change Materials
Solar Refrigeration System Model Studies
Solar powered refrigerator with Thermal Energy Storage
Solar Direct Drive Refrigerator for Vaccine Storage
“SEMINAR REPORT ON SOLAR ASSISTED VAPOUR ADSORPTION REFRIGERATION SYSTEM”Bhagvat Wadekar
SUMMARY
The range of COP for the Solar VAdRS is 0.2 - 0.7. The development of adsorption system for refrigeration is promising. An overall thermodynamics-based comparison of sorption systems shows that the performance of adsorption systems depends highly on both the adsorption pairs and processes. The technology continues to develop and the cost of producing power with solar thermal adsorption refrigeration is falling. If the costs of fossil fuels, transportation, energy conversion, electricity transmission and system maintenance are taken into account, the cost of energy produced by solar thermal adsorption systems would be much lower than that for conventional refrigeration systems.
The intermittent system has its simplicity and cost effectiveness. However, the main disadvantages such as long adsorption/desorption time have become obstacles for commercial production of the system. Hence, to compete with conventional vapor compression technologies, more efforts should be made in enhancing the COP and SCP. The environmental benefits of this technology and its non-dependence on conventional energy sources makes it highly attractive for further developments and a potential alternative to conventional systems in the future. The future of solar refrigeration and air conditioning seems to be a very good proposition and no doubt will find its place in future industrial applications. The major limiting factor at present is the shape of energy so as to make it available whenever it is required, for example at nights and extended cloudy days when we cannot attain a high enough temperature.
A B S T R A C T
In the present paper, an experimental analysis of a solar water heating collector with an integrated latent heat storage unit is presented. With the purpose to determine the performance of a device on a lab scale, but with commercial features, a flat plate solar collector with phase change material (PCM) containers under the absorber plate was constructed and tested. PCM used was a commercial semi-refined light paraffin with a melting point of 60°C. Tests were carried out in outdoor conditions from October 2016 to March 2017 starting at 7:00 AM until the collector does not transfer heat to the water after sunset. Performance variables as water inlet temperature, outlet temperature, mass flow and solar radiation were measured in order to determine a useful heat and the collector efficiency. Furthermore, operating temperatures of the glass cover, air gap, absorber plate, and PCM containers are presented. Other external variables as ambient temperature, humidity and wind speed were measured with a weather station located next to the collector. The developed prototype reached an average thermal efficiency of 24.11% and a maximum outlet temperature of 50°C. Results indicate that the absorber plate reached the PCM melting point in few cases, this suggests that the use of a PCM with a lower melting point could be a potential strategy to increase thermal storage. A thermal analysis and conclusions of the device performance are discussed.
CONTEMPORARY URBAN AFFAIRS (2017) 1(3), 7-12. Doi: 10.25034/ijcua.2018.3672
www.ijcua.com
With the introduction of the government’s Renewable Heat Incentive (RHI), there is an increasing interest in all the technologies associated with the scheme. This CPD gives an overview of a range of policy initiatives in Renewable Heat, an introduction to the different technologies and looks at some of the benefits and issues you need to consider when using renewable heat.
This CPD seminar covers the following topics: Introduction to REHAU, DECC Heat Strategy & Renewable Heat Incentive (RHI), Ground Source Heat Pumps, Biomass Boilers (incl. district heating), Biogas/Anaerobic Digestion, Solar Thermal & Underground Thermal Energy Storage.
Waste heat recovery, co geration and tri-generationAmol Kokare
Diploma in Mechanical Engg.
Babasaheb Phadtare Polytechnic, kalamb-walchandnagar
Sub- Power plant engineering
Unit-Waste heat recovery, co geration and tri-generation.
By- Prof. Kokare Amol Yashwant
• Design and fabrication of a Vapor absorption Refrigeration using solar energy.Nagaraja D Shenoy
The use of solar energy to power refrigeration with replacing the compression cycle with vapor absorption cycle strives to minimize the negative impacts refrigerators have on the environment and energy. Replacing the electrical energy with solar energy will reduce the consumption of high grade electrical energy. Ammonia being an environmentally friendly gas reduces the effect of ozone layer depletion and global warming by artificial refrigerants. This project deals with a model solar thermal refrigeration system using NH3-H2O vapor absorption system
“SEMINAR REPORT ON SOLAR ASSISTED VAPOUR ADSORPTION REFRIGERATION SYSTEM”Bhagvat Wadekar
SUMMARY
The range of COP for the Solar VAdRS is 0.2 - 0.7. The development of adsorption system for refrigeration is promising. An overall thermodynamics-based comparison of sorption systems shows that the performance of adsorption systems depends highly on both the adsorption pairs and processes. The technology continues to develop and the cost of producing power with solar thermal adsorption refrigeration is falling. If the costs of fossil fuels, transportation, energy conversion, electricity transmission and system maintenance are taken into account, the cost of energy produced by solar thermal adsorption systems would be much lower than that for conventional refrigeration systems.
The intermittent system has its simplicity and cost effectiveness. However, the main disadvantages such as long adsorption/desorption time have become obstacles for commercial production of the system. Hence, to compete with conventional vapor compression technologies, more efforts should be made in enhancing the COP and SCP. The environmental benefits of this technology and its non-dependence on conventional energy sources makes it highly attractive for further developments and a potential alternative to conventional systems in the future. The future of solar refrigeration and air conditioning seems to be a very good proposition and no doubt will find its place in future industrial applications. The major limiting factor at present is the shape of energy so as to make it available whenever it is required, for example at nights and extended cloudy days when we cannot attain a high enough temperature.
A B S T R A C T
In the present paper, an experimental analysis of a solar water heating collector with an integrated latent heat storage unit is presented. With the purpose to determine the performance of a device on a lab scale, but with commercial features, a flat plate solar collector with phase change material (PCM) containers under the absorber plate was constructed and tested. PCM used was a commercial semi-refined light paraffin with a melting point of 60°C. Tests were carried out in outdoor conditions from October 2016 to March 2017 starting at 7:00 AM until the collector does not transfer heat to the water after sunset. Performance variables as water inlet temperature, outlet temperature, mass flow and solar radiation were measured in order to determine a useful heat and the collector efficiency. Furthermore, operating temperatures of the glass cover, air gap, absorber plate, and PCM containers are presented. Other external variables as ambient temperature, humidity and wind speed were measured with a weather station located next to the collector. The developed prototype reached an average thermal efficiency of 24.11% and a maximum outlet temperature of 50°C. Results indicate that the absorber plate reached the PCM melting point in few cases, this suggests that the use of a PCM with a lower melting point could be a potential strategy to increase thermal storage. A thermal analysis and conclusions of the device performance are discussed.
CONTEMPORARY URBAN AFFAIRS (2017) 1(3), 7-12. Doi: 10.25034/ijcua.2018.3672
www.ijcua.com
With the introduction of the government’s Renewable Heat Incentive (RHI), there is an increasing interest in all the technologies associated with the scheme. This CPD gives an overview of a range of policy initiatives in Renewable Heat, an introduction to the different technologies and looks at some of the benefits and issues you need to consider when using renewable heat.
This CPD seminar covers the following topics: Introduction to REHAU, DECC Heat Strategy & Renewable Heat Incentive (RHI), Ground Source Heat Pumps, Biomass Boilers (incl. district heating), Biogas/Anaerobic Digestion, Solar Thermal & Underground Thermal Energy Storage.
Waste heat recovery, co geration and tri-generationAmol Kokare
Diploma in Mechanical Engg.
Babasaheb Phadtare Polytechnic, kalamb-walchandnagar
Sub- Power plant engineering
Unit-Waste heat recovery, co geration and tri-generation.
By- Prof. Kokare Amol Yashwant
• Design and fabrication of a Vapor absorption Refrigeration using solar energy.Nagaraja D Shenoy
The use of solar energy to power refrigeration with replacing the compression cycle with vapor absorption cycle strives to minimize the negative impacts refrigerators have on the environment and energy. Replacing the electrical energy with solar energy will reduce the consumption of high grade electrical energy. Ammonia being an environmentally friendly gas reduces the effect of ozone layer depletion and global warming by artificial refrigerants. This project deals with a model solar thermal refrigeration system using NH3-H2O vapor absorption system
”Waste heat recovery” is the process of “heat integration”, that is, reusing heat energy that would otherwise be disposed of or simply released into the atmosphere. By recovering waste heat, plants can reduce energy costs and CO2 emissions, while simultaneously increasing energy efficiency.
Classification, Advantages and applications, Commercially viable
waste heat recovery devices, Saving potential.
Waste heat is heat, which is generated in a process by way of fuel combustion or chemical
reaction, and then “dumped” into the environment even though it could still be reused for some
useful and economic purpose. The essential quality of heat is not the amount but rather its
“value”. The strategy of how to recover this heat depends in part on the temperature of the waste
heat gases and the economics involved.
WASTE HEAT RECOVERY TO INCREASE BOILER EFFICIENCY USING BAGASSE AS FUEL IAEME Publication
Many industrial heating processes generate waste energy in textile industry; especially exhaust gas from the boiler at the same time reducing global warming. Waste heat found in the
exhaust gas can be used to preheat the incoming gas. This is one of the basic methods for recovery of waste heat. Therefore, this article will present a study the way to recovery heat waste from boiler exhaust gas by mean of shell and tube heat exchanger.
Download Link (Copy URL):
https://sites.google.com/view/varunpratapsingh/teaching-engagements
Syllabus:
Availability and Irreversibility
Availability Function
Second Law Efficiencies
Work Potential Associated with Internal Energy
Waste Heat Recovery
Heat Losses – Quality vs. Quantity
Principle of Heat Recovery Units
Classification of WHRS on Temperature Range Bases
Commercial Viable Waste Heat Recovery Devices
Benefits of Waste Heat Recovery
Development of a Waste Heat Recovery System
Commercial Waste Heat Recovery Devices
West Heat Recovery Boiler (WHRB)
Recuperators- Regenerative, Ceramic, Regenerative Heat Exchanger
Thermal wheel/ Heat Wheel
Heat Pipe
Economiser
Feed Water
Heat Pump
Shell and Tube Heat Exchanger
Plate Heat Exchanger
Run-around coil
Direct Contact Heat Exchanger
Advantages and Limitations of WHRD’s
a). EconomiserAn economiser is a mechanical device which is used a.pdfrajat630669
a). Economiser
An economiser is a mechanical device which is used as a heat exchanger by preheating a fluid to
reduce energy consumption. In a steam boiler, it is a heat ex-changer device that heats up fluids
or recovers residual heat from the combustion product i.e. flue gases in thermal power plant
before being released through the chimney. Flue gases are the combustion exhaust gases
produced at power plants consist of mostly nitrogen, carbon dioxide, water vapor, soot carbon
monoxide etc. Hence, the economiser in thermal power plants, is used to economise the process
of electrical power generation, as the name of the device is suggestive of. The recovered heat is
in turn used to preheat the boiler feed water, that will eventually be converted to super-heated
steam. Thus, saving on fuel consumption and economising the process to a large extent, as we
are essentially gathering the waste heat and applying it to, where it is required. Nowadays
however, in addition to that, the heat available in the exhaust flue gases can be economically
recovered using air pre-heater which are essential in all pulverized coal fired boiler.
b). Reheater
ins some heat either from the combustion gases leaving the boiler (if there is still much
temperature difference) or by adding more heat by burning small amount of fuel. The energy of
the exhaust steam with the gained heat increases the steam enthalpy of the steam and give a good
opportunity to generate much work with the low pressure turbine. The two works (High pressure
W_H and Low pressure W_L) are much greater than the heat added by fuel burned (Q1 and Q2),
so the efficiency increases. Another issue, the reheat helps in saving the turbine blades from
corrosion due to low dryness fraction x<0.88 which it may occur if one single stage turbine is
used.
c). Cogeneration
Cogeneration (Combined Heat and Power or CHP) is the simultaneous production of electricity
and heat, both of which are used. The central and most fundamental principle of cogeneration is
that, in order to maximise the many benefits that arise from it, systems should be based on the
heat demand of the application. This can be an individual building, an industrial factory or a
town/city served by district heat/cooling. Through the utilisation of the heat, the efficiency of a
cogeneration plant can reach 90% or more.
Cogeneration therefore offers energy savings ranging between 15-40% when compared against
the supply of electricity and heat from conventional power stations and boilers.
Cogeneration optimises the energy supply to all types of consumers, with the followingbenefits
for both users and society at large:
d). Turbocharging
A turbocharger, or turbo (colloquialism), from Greek \"\" (\"wake\"),[1] (also from Latin
\"turbo\" (\"spinning top\"),[2]) is aturbine-driven forced induction device that increases an
internal combustion engine\'s efficiency and power output by forcing extra air into the
combustion chamber.[3][4] This improvement over a.
Enhancing Energy Efficiency of Thermochemical Vacuum-Processes and SystemsALD Vacuum Systems Inc.
The energy optimization of thermoprocessing equipment is of great ecological and economical importance. Thermoprocessing equipment consumes up to 40% of the energy used in industrial applications in Germany. Therefore it is necessary to increase the energy efficiency of thermoprocessing equipment in order to meet the EU’s targets to reduce greenhouse gas emissions. In order to exploit the potential for energy savings, it is essential to analyze and optimize processes and plants as well as operating methods of electrically heated vacuum plants used in large scale production.
Alfred Piggott 2012.05.31 Industrial Waste Heat Recovery Thermal Literature Review
1. Credit: Department of Energy
Industrial Waste Heat Recovery
Alfred Piggott
4/20/2012
MEEM 4220 – Internal Combustion Engines
2. 1.0 Introduction ....................................................................................................................................... 3
Table of Contents
2.0 Waste Heat Grades .......................................................................................................................... 3
3.0 Systems for Waste heat Recovery ............................................................................................. 5
3.1 Heat Exchangers .......................................................................................................................... 5
3.2 Load Preheating .......................................................................................................................... 5
3.3 Low Grade Recovery .................................................................................................................. 5
3.3.1 Deep Economizers.............................................................................................................. 6
3.3.2 Indirect Contact Condensation Recovery.................................................................. 6
3.3.3 Direct Contact Condensation Recovery ..................................................................... 6
3.3.4 Transport Membrane Condenser ................................................................................. 6
3.3.5 Heat Pumps ........................................................................................................................... 6
3.3.6 Closed compression cycles ............................................................................................. 6
3.3.7 Open Cycle Vapor Recompression ............................................................................... 6
3.3.8 Absorption Heat Pumps ................................................................................................... 6
3.4 Power Generation ....................................................................................................................... 7
3.4.1 Generating Power via Mechanical work .................................................................... 7
3.4.2 Direct Electrical Conversion Systems ......................................................................... 7
4.0 Conclusion .......................................................................................................................................... 8
5.0 Bibliography ...................................................................................................................................... 9
Waste Heat Recovery Page 2 of 9
3. 1.0 Introduction
As fuel prices rise, supplies decrease, and concerns about environmental impact intensify, we
start looking for new and better energy sources. A pollution-free source of energy that is
often overlooked is waste heat. Waste heat is a byproduct of converting energy from one
form to another. As governed by the second law of thermodynamics, no process of energy
conversion is 100% efficient. Typical fossil fuel energy conversion processes include
converting coal or natural gas to electricity or gasoline to vehicle power.
In 2008 world energy consumption was roughly 505 quadrillion BTU (505 X 1015 BTU) (1).
Conversion of fossil fuels to usable energy accounts for roughly 84% (1) of the world energy
consumption. The efficiency of these fossil fuel conversion processes tends to be around 28-
43% (2). This means 57-72% or 217-288 quadrillion BTU is turned to heat and not part of
the usable output. This equates to roughly 4-5 times more energy going to waste heat than all
the renewable energy (Wind, Solar, Hydropower, Biomass, Geothermal) usage which was
about 50 quadrillion BTU in 2008 (1).
2.0 Waste Heat Grades
The second law of thermodynamics also governs the amount of waste heat that can be
recovered. The higher the temperature of the waste heat, the greater the proportion that can
be recovered. This can be seen with the equation for Carnot efficiency (equation 1). TH is the
temperature of the waste heat and TL is the temperature of the environment, for example the
ambient air temperature or the temperature of a lake or river where a portion of heat not
recovered will be “dumped”.
𝑇𝐿
𝜂 𝐶𝑎𝑟𝑛𝑜𝑡 = 1 −
𝑇𝐻
Equation 1: Carnot Efficiency
Waste heat temperatures are generally classified into three categories (3). These categories
were chosen based on typical industrial waste heat temperatures and the commercially
available equipment to recover the waste heat.
High-Grade 1100 ≤ TH ≤ 3000◦F (590-1650◦C)
Medium-Grade 400 ≤ TH ≤ 1100◦F (205-590◦C)
Low-Grade 80 ≤ TH ≤ 400◦F (27-205◦C)
Table 1 shows various sources of high-grade waste heat. Although high-grade waste heat can
be recovered at a higher efficiency than the lower grades, the cost to do so will be higher due
to special materials and equipment design needed to withstand the higher temperatures.
Waste Heat Recovery Page 3 of 9
4. Table 1: Sources of High Grade Waste Heat [Source (3)]
Table 2 shows sources of medium grade waste heat. This is a temperature range that can still
be economical (3) without the higher cost associated with high-grade recovery conversion
equipment.
Table 2: Sources of Medium Grade Waste Heat [Source (3)]
Table 3 shows sources of low-grade heat. Due to low efficiency at these temperatures, it is
typically not economical to extract work from these sources. Some applications include
preheating process gases, liquids, solids, or space heating.
Waste Heat Recovery Page 4 of 9
5. Table 3: Source of Lowe Grade Waste Heat [Source (3)]
3.0 Systems for Waste heat Recovery
3.1 Heat Exchangers
In medium to high temperature heat recovery systems, heat exchangers use heat from
combustion exhaust gases to preheat pre-combustion incoming air. This reduces the amount
of heat taken from combustion to heat the air and thus more combustion heat is available to
run the intended process. There are many types of heat exchangers used, these include
recuperators, regenerators, heat wheels, passive air preheaters, heat pipes, waste heat boilers
and finned tube heat exchangers / economizers. Each of these has advantages and
disadvantages for a given application.
3.2 Load Preheating
Load preheating refers to the preheating solid materials entering a plant with the waste heat
from the plant process. An example of solid preheating is using the waste heat from a braze
furnace to preheat the parts that will be brazed. This reduces the load on the furnaces and
thus reduced energy consumption.
3.3 Low Grade Recovery
As in high and medium grade waste heat recovery, low-grade waste heat recovery also uses
heat exchangers to accomplish the task. Low-grade recovery has a different set of challenges
than medium and high-grade waste heat recovery. The main challenges are corrosion, large
heat transfer surfaces, and finding a use for recovered heat. Corrosion becomes a challenge
because these heat exchangers cool the gases to a low enough temperature that vapors
condense. These combustion vapors are highly corrosive. Another challenge for low-grade
Waste Heat Recovery Page 5 of 9
6. recovery is the size of the heat exchanger. The laws of heat transfer require a larger surface
area for heat transfer if the difference in temperature of the hot side and cold side is smaller.
3.3.1 Deep Economizers
Deep economizers are corrosion resistant heat exchangers designed to cool exhaust gases to
low-grade 150-160ºF. The heat recovered from the exhaust gas can then be used for another
process.
3.3.2 Indirect Contact Condensation Recovery
Indirect contact condensation recovery units are corrosion resistant shell and tube heat
exchangers that can cool gases enough (100-110ºF) to completely condense vapor which in
turn increases their efficiency.
3.3.3 Direct Contact Condensation Recovery
Direct contact condensation recovery heat exchangers mix process “waste” steam with
cooling fluid that is used to heat or preheat an external system. The direct contact of steam
with the cooling fluid makes this process more efficient than an indirect contact heat
exchanger.
3.3.4 Transport Membrane Condenser
A transport membrane condenser uses capillary action to condense combustion gas vapor
and recover latent heat for use in another process.
3.3.5 Heat Pumps
Heat pumps can increase the temperature of low-grade waste heat for usage in a process that
requires a higher temperature. In certain cases this can be done economically depending on
the temperature rise needed and the cost of fuel and electricity.
3.3.6 Closed compression cycles
The closed compression cycle is essentially a heat pump. This cycle removes heat from one
fluid loop where cooling is needed and adds that heat to another fluid loop where heating is
needed.
3.3.7 Open Cycle Vapor Recompression
These systems use either mechanical or thermal compression to increase the pressure and
thus the temperature of a waste side vapor. This allows the heat to be used in processes
where a higher temperature is needed.
3.3.8 Absorption Heat Pumps
The operation of an absorption heat pump is similar to the closed cycle compression system
but instead of using mechanical compression it uses chemical means driven by heat.
Waste Heat Recovery Page 6 of 9
7. 3.4 Power Generation
Power generation from waste heat typically involves using waste heat to generate mechanical
energy, which subsequently drives an electrical generator. Prevailing technologies for
accomplishing this are the steam Rankine cycle, organic Rankine cycle and the Kalina cycle.
Other types of power generation that currently have not been demonstrated for large-scale
industrial use are thermoelectric, piezoelectric, thermionic and thermal voltaic power
generation. These types convert heat directly to electrical energy.
3.4.1 Generating Power via Mechanical work
3.4.1.1 Steam Rankine Cycle
The most common system that converts heat to mechanical work is the steam Rankine cycle.
This system is typically used for medium grade waste heat as it becomes less economical for
low-grade heat. Furthermore, if temperatures are too low, superheat will not be achieved and
if superheat is not achieved, condensation and erosion of turbine blades will occur.
3.4.1.2 Organic Rankine Cycle
Organic Rankine cycle is much more suitable for low temperature waste heat recovery. This
suitability comes from the organic working fluid, which has a higher vapor pressure and a
lower boiling point than water. The higher molecular mass of the organic working fluid also
allows for smaller turbine design due to more energy imparted on the turbine blade per unit
area.
3.4.1.3 Kalina Cycle
The Kalina cycle is basically a Rankine cycle that uses a mixture of two non-reacting fluids.
The benefit of using two fluids is better thermal matching to the waste heat source. This
thermal matching allows the Kalina cycle to achieve significant efficiency gains over the one
fluid Rankine cycle.
3.4.2 Direct Electrical Conversion Systems
3.4.2.1 Thermoelectric Generation
Thermoelectric generators (TEG) utilize the Seebeck effect to convert heat directly to
electricity. When two different semiconductors are connected electrically in series and a
temperature differential is applied, a voltage is created across the series. Thermoelectric
materials are suitable for medium and high-grade waste heat recovery. Currently the costs are
high and efficiencies are relatively low compared with the Rankine cycles. Advances in
materials will make thermoelectric power generation more competitive.
Waste Heat Recovery Page 7 of 9
8. 3.4.2.2 Piezoelectric Power Generation
Piezoelectric Power Generation (PEPG) converts mechanical vibrations into electricity.
These vibrations come from oscillating gas expansion processes. PEPG are suitable for low-
grade heat recovery. These devices are currently very low efficiency and high cost.
3.4.2.3 Thermionic Generation
Thermionic generation devices operate on the principle of thermionic emission. Thermionic
emission is produced when a temperature difference across two metal oxide plates separated
in a vacuum causes electrons to flow through the vacuum gap. These devices are suitable for
high and low-grade heat sources.
3.4.2.4 Thermophotovoltaic (TPV) Generator
TPV generators operate by converting radiant heat into electricity. The heat source heats an
emitter, which gives off electromagnetic radiation. This radiation travels through a filter and
on to the Photovoltaic cell that converts the radiation into electricity.
4.0 Conclusion
Waste heat is a large potential source of pollution free energy. The maximum efficiency of
the system used to recover waste heat depends on the temperature of the heat and is
governed by laws of thermodynamics. There are many types of waste heat recovery
equipment, each with its own pros and cons depending on the characteristics of the waste
heat source. In the future, it will be possible to convert heat directly to electricity
economically on a larger scale with solid-state devices.
Waste Heat Recovery Page 8 of 9
9. 5.0 Bibliography
1. "International Energy Outlook 2011." U.S. Energy Information Administration (EIA). Sept.
2011. Web. 7 Mar. 2011. <http://www.eia.gov/forecasts/ieo/pdf/0484(2011).pdf>.
2. "Environmental Footprints and Costs of Coal-Based Integrated Gasification Combined Cycle
and Pulverized Coal Technologies." United States Environmental Protection Agency. Nexant,
Inc., July 2006. Web. 7 Mar. 2012. <2.
http://www.epa.gov/air/caaac/coaltech/2007_01_epaigcc.pdf>.
3. Doty, Steve, and Wayne C. Turner. Energy Management Handbook - Seventh Addition. 7th ed.
Lilburn: Fairmont, 2009. Print.
4. "Waste Heat Recovery: Technology and Opportunities in the U.S. Industry." U.S. Department
of Energy Efficiency and Renewable Energy. BCS Incorporated, Mar. 2008. Web. 10 Mar. 2012.
<http://www1.eere.energy.gov/industry/intensiveprocesses/pdfs/waste_heat_recovery.pdf>.
Waste Heat Recovery Page 9 of 9