Thermoelectric Materials: Converting Heat to Electricity

When we think of using electricity one of the prevalent uses is to provide a heat source.  We see this in our everyday lives as ranges and ovens, microwaves, kettles, hot water tanks, baseboard heaters, as well as other applications.  So how about reversing the process and capturing heat and directly converting to electricity, is this possible?  As it happens there is a classification of materials which have a property called a thermoelectric effect.

Boosting energy efficiency is an important element of the transition to a sustainable energy system. There are big savings to be made. For example, less than half the energy content of diesel is actually used to power a diesel truck. The rest is lost, mostly in the form of heat. Many industrial processes also deal with the problem of excessive .

That’s why many research teams are working to develop that can convert waste heat into energy. But it’s no easy task. To efficiently convert heat to electricity, the materials need to be good at conducting electricity, but at the same time poor at conducting heat. For many materials, that’s a contradiction in terms.

“One particular challenge is creating thermoelectric materials that are so stable that they work well at high temperatures,” says Anders Palmqvist, professor of materials chemistry, who is conducting research on thermoelectric materials. (1)

2dthermoelec.jpg

Image 1:  The enlarged illustration (in the circle) shows a 2D electron gas on the surface of a zinc oxide semiconductor. When exposed to a temperature difference, the 2D region exhibits a significantly higher thermoelectric performance compared to that of bulk zinc oxide. The bottom figure shows that the electronic density of states distribution is quantized for 2D and continuous for 3D materials. Credit: Shimizu et al. ©2016 PNAS

The thermoelectric effect is not as efficient as converting electricity to heat, which is generally 100% efficient.  However, with waste energy streams even a small conversion rate may return a significant flow of usable electricity which would normally go up a stack or out a tailpipe.

The large amount of waste heat produced by power plants and automobile engines can be converted into electricity due to the thermoelectric effect, a physics effect that converts temperature differences into electrical energy. Now in a new study, researchers have confirmed theoretical predictions that two-dimensional (2D) materials—those that are as thin as a single nanometer—exhibit a significantly higher thermoelectric effect than three-dimensional (3D) materials, which are typically used for these applications.

The study, which is published in a recent issue of the Proceedings of the National Academy of Sciences by Sunao Shimizu et al., could provide a way to improve the recycling of into useful energy.

Previous research has predicted that 2D materials should have better thermoelectric properties than 3D materials because the electrons in 2D materials are more tightly confined in a much smaller space. This confinement effect changes the way that the electrons can arrange themselves. In 3D materials, this arrangement (called the density of states distribution) is continuous, but in 2D materials, this distribution becomes quantized—only certain values are allowed. At certain densities, the quantization means that less energy is required to move electrons around, which in turn increases the efficiency with which the material can convert heat into . (2)

 

Related Articles:

References:

  1. http://phys.org/news/2016-06-track-electricity.html#jCp
  2. http://phys.org/news/2016-06-electricity-dimensions.html#jCp

Why I did not upgrade to Windows 10

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I am so happy to see those nag messages disappear from my computer, you know the ones reminding you that your period of time to upgrade to Windows 10 will expire on July 31?   Now that we are in August one less thing popping up that bothers me.

The question being do I upgrade or not?  And friends and family who look to me for advice on such issues want to know what I am doing and why.  Intuitively I felt that upgrading was unwise likely do to past experiences with O/S upgrades and backward compatibility of existing hardware and external devices.

Coolpix 995

For example, I own an older Nikon digital camera, Coolpix 995, which is a newer version of my first digital camera, a Coolpix 990.  Getting software that works for this camera for versions of Windows newer than XP has currently been a challenge.  Driver’s are not available for Windows Vista, 7 and definitely not for Window’s 10.  So such is likely for any devices I currently own.

Also, I like to buy used equipment at bargain prices.  I have learned through my own experience that electronic equipment has a short shelf life and prices drop quickly as newer versions of equipment enter the market.  By creating obsolescence in software, hardware becomes prematurely unusable due to compatibility issues.  When this occurs the current solution is usually to discard the item and buy a new replacement.

HP8530W_Elitebook

Another thing besides compatibility and premature obsolescence is extra work and other unknown issues which will inevitably arise from the upgrade.  I have an ‘Elitebook’ HP 8530 W laptop computer with Window’s 7 for my business and personal use, which I purchased for a bargain on Ebay.  I have spent a lot of time setting it up to work properly, I have no need to upgrade the software.

Let someone else figure it all out, then maybe in a couple of years I will buy a more powerful model at a lower price with Windows 10 or the current version already installed.   So I did not upgrade, and I am okay with that.

 

 

 

Entrepreneurial Value and Energy Conservation

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Photo of Arbutus Mall, Vancouver

As an engineer and self-proclaimed entrepreneur I find myself value driven when seeking opportunities.  Usually value is something which can measured, whether it be in profit, market share, response rate, efficiency in operations and resource management, or other metric.  It may be to date unrecognized or otherwise under-utilized or untapped resource which can be subject to improvements or other opportunities.

Education of the market can be a daunting task, and getting recognition may be challenging.  However, perseverance and targeted marketing can eventually lead to opportunities where value can be recognized in a structured manner where a service contract may be offered to complete the scope of the determined project.  Here are some personal thoughts that I am putting down in a Q/A format:

Q.  Why do I write a blog?

A.  Writing a blog on energy in our built and constructed world has multiple benefits.  I get to practice my writing and research skills, learn new and emerging technology, meet new people, continue my growth as an individual and professional, and publish my research.

Q.  Why do I write about energy?

A.  One of the reasons I choose energy conservation and efficiency is my own understanding of how we can rationalize construction projects and work by building operations savings.  In the past with failing mechanical systems in buildings I have specified upgrades to the building plant to improve operations and partially pay for the repairs and upgrades by operational savings.

Q.  What kind of professional services are needed in buildings?

A.  To start we must to perform baseline measurements of the building.  Before changes are made so as to establish existing consumption rates of energy and water, as well as waste streams.  By doing this we can examine methods of reducing consumption rates and establish priorities for improvements and budget proposals for improvements in building equipment, the building envelope, electrical and lighting, as well as fixing ongoing problems or other deficiencies.  Generally speaking, a building energy audit and report is proposed start to this process, where an informal meeting with building staff, obtaining existing plans and doing an initial onsite inspection of operations and systems.

Q.  How can we achieve energy savings and be more green?

A.  Small and local things can add up, this is a fundamental tenet of conservation.  Every act gets examined, where is the waste, what can be reduced, is it needed, how can we do this differently.  All questions need to be asked and answered where an environment is occupied, and can be quite intensive where industry or other energy intensive commercial enterprise may be involved.

Q.  Why do I need an outside consultant or professional to perform this work?

A.  There are many tools a consultant can use and bring to the table with a client.   Knowledge and understanding of systems are important and how they fit together, someone who has experience in systems design, has worked in the field and can provide a service to either establish an initial plan to overseeing the entire project, including design, execution and final occupancy.

Q.  What else is important besides an energy audit?

A.  After an energy audit, building condition review and report may follow a request for proposal if it is determined by the client that repairs are required and a budget for these may be established prior to commencing work.  Within the proposal will be a preliminary scope or statement of work.

 

 

Energy Efficiency Financing for Existing Buildings in California

Much of our efforts to reduce carbon emissions involves fairly complicated and advanced technologies. Whether it’s solar panels, batteries, flywheels, or fuel cells, these technologies have typically required public support to bring them to scale at a reasonable price, along with significant regulatory or legal reforms to accommodate these new ways of doing old things, […]

To recommend policies to boost this capital market financing for energy retrofits, UC Berkeley and UCLA Law are today releasing a new report “Powering the Savings:How California Can Tap the Energy Efficiency Potential in Existing Commercial Buildings.” The report is the 17th in the two law schools’ Climate Change and Business Research Initiative, generously supported by Bank of America since 2009.

The report describes ways that California could unlock more private investment in energy efficiency retrofits, particularly in commercial buildings.  This financing will flow if there’s a predictable, long-term, measured and verified amount of savings that can be directly traced to energy efficiency measures.  New software and methodologies can now more accurately perform this task.  They establish a building’s energy performance baseline, calibrating for a variety of factors, such as weather, building use, and occupancy changes.  That calibrated or “dynamic” baseline can then form the basis for calculating the energy savings that occur due specifically to efficiency improvements.

But the state currently lacks a uniform, state-sanctioned methodology and technology standard, so utilities are reluctant to base efficiency incentives or programs without regulatory approval to use these new methods.  The report therefore recommends that energy regulators encourage utilities to develop aggressive projects based on these emerging metering technologies that can ultimately inform a standard measurement process and catalyze “pay-for-performance” energy efficiency financing, with utilities able to procure energy efficiency savings just like they were a traditional generation resource. […]

via Solving The Energy Efficiency Puzzle — Legal Planet

It takes money to make money: getting money to flow into energy efficiency projects

Energy in Demand - Sustainable Energy - Rod Janssen

Jim Barrett, Chief Economist, for ACEEE, The American Council for an Energy-Efficient Economy, writes an excellent blog on the ACEEE website about an initiative by the Bank of America to increase investments at the community level.

Bank of America’s Energy Efficiency Financing Program shows path to combining energy savings and community development

If you spend any time with the energy efficiency crowd, you will often hear us call it the lowest cost energy resource out there. What you will never hear us say is that energy efficiency is free. Efficiency can do many great things: It saves money, cuts pollution, increases productivity, and creates jobs. What it can’t do is defy one of the fundamental laws that governs all investments—it takes money to make money.

We want to get money flowing into well-designed energy efficiency projects, especially those that can do the most good where it is the most needed…

View original post 1,011 more words

Overly Simple Energy-Economy Models Give Misleading Answers

Does it make a difference if our models of energy and the economy are overly simple? I would argue that it depends on what we plan to use the models for. If all we want to do is determine approximately how many years in the future energy supplies will turn down, then a simple model is perfectly sufficient. But if we want to determine how we might change the current economy to make it hold up better against the forces it is facing, we need a more complex model that explains the economy’s real problems as we reach limits.We need a model that tells the correct shape of the curve, as well as the approximate timing. I suggest reading my recent post regarding complexity and its effects as background for this post.

The common lay interpretation of simple models is that running out of energy supplies can be expected to be our overwhelming problem in the future. A more complete model suggests that our problems as we approach limits are likely to be quite different: growing wealth disparity, inability to maintain complex infrastructure, and growing debt problems.Energy supplies that look easy to extract will not, in fact, be available because prices will not rise high enough. These problems can be expected to change the shape of the curve of future energy consumption to one with a fairly fast decline, such as the Seneca Cliff.

Source: Overly Simple Energy-Economy Models Give Misleading Answers

How Energy Shapes the Economy

In the beginning, the Master Economist created the Economy.  He created businesses large and small, consumers, governments with their regulation, and financial institutions of all types. And the Ma…

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Source: How Energy Shapes the Economy

Flow Batteries: Developments in Energy Storage Systems (ESS)

The need for large scale storage solutions come to the forefront as a means to adjust supply to demand on the electrical grid.  Energy storage systems can adjust time of delivery to eliminate the need for peaker plants, allow for the addition of intermittent renewable energy sources such as wind and solar, or allow for large users to reduce facility operating costs by using a storage system to supplement energy supply reducing peak demand, most notably for summer A/C loads in buildings.

vanadium-flow-battery-wind-energy

Out of engineering research laboratories in materials science and electro-chemistry  are coming new energy storage systems designed for the future to solve these issues meanwhile opening up new enterprises and industry.  The characteristics of an ideal flow battery would include:  a long service life, modularity and scalability, no standby losses, chargeability, low maintenance, and safe.  In addition a flow battery will have to be economic compared to other systems which will need to be determined using LCOE analysis.

Related Articles:

  1. https://duanetilden.com/2015/01/27/determining-the-true-cost-lcoe-of-battery-energy-storage/
  2. https://duanetilden.com/2015/01/26/what-is-levelized-cost-of-energy-or-lcoe/
  3. https://duanetilden.com/2016/01/18/energy-storage-compared-to-conventional-resources-using-lcoe-analysis/
  4. https://duanetilden.com/2015/02/17/vanadium-flow-battery-competes-with-lithium-and-lead-acid-at-grid-scale/ 

Links:

 

 

Measuring and Monitoring Energy Efficiency

Defining Energy Efficiency

To begin, let us ask what is energy efficiency, what are it’s components and how is it measured.  To make comparisons we need to gather data using measures relevant to the industry in question, also to the input forms of energy, waste streams and the useful work performed.  In the case of a building we may use meters to measure consumption or utility bills and compare changes in consumption rates over time.

To an engineer, energy efficiency is the ratio of useful work over total energy input.  For example, a room air conditioner’s efficiency is measured by the energy efficiency ratio (EER). The EER is the ratio of the cooling capacity (in British thermal units [Btu] per hour) to the power input (in watts).

On a grander scale we may be looking improvements over an industry or sector, changing fuel types in a utility such as the conversion of a coal plant to the production of power fueled by natural gas to reduce the carbon load on the environment.  Efficiency may be measured by different metrics depending on the result sought and may include the environmental impact of waste streams.

EnergyEfficientEconomy

Figure 1:  Historical Energy Use Graph  (1)

Whatever the exact yearly investment figure, the historical economic impact of efficiency is quite clear. As the graph () shows, efficiency has provided three times more of the economic services than new production since 1970:

The blue line illustrates demand for energy services (the economic activity associated with energy use) since 1970; the solid red line shows energy use; and the green line illustrates the gain in energy efficiency. While demand for energy services has tripled in the last four decades, actual energy consumption has only grown by 40 percent. Meanwhile, the energy intensity of our economy has fallen by half.

The area between the solid red line and the blue line represents the amount of energy we did not need to consume since 1970; the area between the dashed red line and the solid red line indicates how much energy we consumed since 1970.

The chart shows that energy efficiency met nearly three quarters of the demand for services, while energy supply met only one quarter.

“One immediate conclusion from this assessment is that the productivity of our economy may be more directly tied to greater levels of energy efficiency rather than a continued mining and drilling for new energy resources,” wrote Laitner. (1)

As noted in an article by the EIA;  The central question in the measurement of energy efficiency may really be “efficient with respect to what?” (2)  In general terms when discussing energy efficiency improvements we mean to perform more of a function with the same or less energy or material input.

Energy Efficiency Measures

Energy efficiency measures are those improvement opportunities which exist in a system which when taken will achieve the goals of achieving greater performance.  For example refer to Table 1 of Energy Efficiency Measures which can be effectively reduce energy consumption and provide an ROI of 5 or less years when applied to the commercial refrigeration industry.

energy efficient refrigeration4.jpg

Table 1:  Commercial Refrigeration Energy Efficiency Measures (3)


Government Action on Energy Efficiency

Energy efficiency has been put forward as one of the most effective methods in efforts to address the issue of Climate Change.  Recently, on February 19, 2015, President Obama signed Executive Order (EO) 13693.

“Since the Federal Government is the single largest consumer of energy in the Nation, Federal emissions reductions will have broad impacts.  The goals of EO 13693 build on the strong progress made by Federal agencies during the first six years of the Administration under President Obama’s 2009 Executive Order on Federal Leadership on Environmental, Energy and Economic Performance, including reducing Federal GHG emissions by 17 percent — which helped Federal agencies avoid $1.8 billion in cumulative energy costs — and increasing the share of renewable energy consumption to 9 percent.  

With a footprint that includes 360,000 buildings, 650,000 fleet vehicles, and $445 billion spent annually on goods and services, the Federal Government’s actions to reduce pollution, support renewable energy, and operate more efficiently can make a significant impact on national emissions. This EO builds on the Federal Government’s significant progress in reducing emissions to drive further sustainability actions through the next decade. In addition to cutting emissions and increasing the use of renewable energy, the Executive Order outlines a number of additional measures to make the Federal Government’s operations more sustainable, efficient and energy-secure while saving taxpayer dollars. Specifically, the Executive Order directs Federal agencies to:

– Ensure 25 percent of their total energy (electric and thermal) consumption is from clean energy sources by 2025.

– Reduce energy use in Federal buildings by 2.5 percent per year between 2015 and 2025.

– Reduce per-mile GHG emissions from Federal fleets by 30 percent from 2014 levels by 2025, and increase the percentage of zero emission and plug in hybrid vehicles in Federal fleets.

– Reduce water intensity in Federal buildings by 2 percent per year through 2025. ” (4)


Summary

Energy efficiency has gained recognition as a leading method to reduce the emissions of GHG’s seen to be the cause of climate change.  Under scrutiny, we find that there are different measures of efficiency across different industry, fuel types and levels.  For example on a micro-level, the functioning of a system may be improved by including higher efficiency components in it’s design, such as motors and pumps.

However, there are other changes which can improve efficiency.  Adding automated computer controls can improve a system level efficiency.   Utilities may change from coal burning to natural gas fired power plants, or industry may convert to a process to include for co-generation.  Battery storage and other technological improvements may come along to fill in the gap.

Historically Energy Efficiency measures have proven to be gaining ground by employing people with the savings earned when applying measures to reduce consumption.  These savings reverberate through the economy in a meaningful way, by reducing the need for the construction of more power plants as one example as we on an individual level.  We consume less energy, and using higher efficiency electronic equipment, and other energy savings measures at a consumer level, our communities are capable of more growth with existing energy supplies.

jEnergy production and consumption, as well as population growths also arise to other issues related to energy consumption, such as water consumption, water waste, and solid material waste.  Building with sustainable materials which promote healthy living environments is gaining importance as we understand the health impacts of a building’s environment on the health and well-being of the occupants.  Energy efficiency in the modern era, as we see from recent government mandates and sustainability programs, such as LEED’s for one, also includes for reductions in water intensity and incorporation of renewable energy programs as an alternative to increasing demand on existing utilities.

 

 

Related Blog Posts:

References

  1. http://www.greentechmedia.com/articles/read/report-u.s.-energy-efficiency-is-a-bigger-industry-than-energy-supply
  2. http://www.eia.gov/emeu/efficiency/measure_discussion.htm
  3. http://www.nwfpa.org/nwfpa.info/component/content/article/52-refrigeration/284-energy-efficient-refrigeration-systems
  4. https://www.whitehouse.gov/administration/eop/ceq/sustainability