Efficiency Gains for Diesel Generators Using Stirling Engine Waste Heat Recovery

For years diesel generators have provided for basic electrical power needs in industrial, commercial, military and off-grid markets, especially in developing nations. Besides being a source of air pollution, one of the major challenges with diesel generators in remote areas and developing nations is fuel. Fuel costs in many of these areas are heavily subsidized and vulnerable to price fluctuations. In many smaller towns and villages, the distribution, logistics and delivery of the fuel is not consistent or predictable.

In addition to the fuel pricing and distribution challenges, less-efficient diesel generators intensify local air pollution and climate change challenges. According to a Renewable Energy Policy Project (REPP) research report, emissions in the just the U.S. from diesel generators in 2010 are predicted to be over 370,885 tons of NO_X and 16.6 million tons of CO₂. Diesel generator manufacturers such as Cummins, DRS Fermont, Caterpillar, L-3 and Kubota continuously pursue efficiency gains in their designs.  Waste heat recovery methods such as the Cool Energy technology approach provides can improve efficiency by 10% – 15%.

In addition to solar thermal applications, the Cool Energy SolarHeart® Engine can be coupled directly with diesel generators to increase the overall operating efficiency. It is estimated that over 60% of the total energy generated in a diesel generator is wasted through the exhaust or the cooling jacket/radiator. The SolarHeart Stirling engine converts these relatively low temperatures (<250°C) to mechanical motion which drives the internal electrical generator. Using the waste heat from both the exhaust and the cooling jacket, it is estimated that efficiency gains of 15% could be obtained. Since there is no combustion internal to the SolarHeat Engine, there is no additional pollution created. The current SolarHeart Engine can produce 1.5 kW of power and future models will go as high as 25 kW, to couple with diesel gensets in the 10kW to 250kW range.

Exciting Technology Milestone – 1550 Watts output

Yesterday the Cool Energy team hit a new milestone for our third generation Stirling engine prototype: 1550 watts of output power!  This is a new high-water mark for output power and efficiency, and represents the results of a low-cost breakthrough in the piston/cylinder seal geometry.  This output will work well in the initial pilot installation planned for early next year at the University of Colorado.  Congratulations to the team!

Solar Thermal Industry Overview

An exceptionally well-researched overview of the worldwide solar thermal heating market came out last month in Renewable Energy World.  Reading between the lines and putting information in this post together with data from the REN21 project, it appears that about 28 million square meters of non-tracking solar thermal collectors were installed in 2007, with about 30-40% of that area being evacuated tube collectors, and the remainder flat-plate collectors and pool heating collectors.

Almost all of the new solar thermal collectors in the world (16 GW – 80%) are installed in China, which indicates the cost-effectiveness of the approach.  Most of the remainder are installed in Europe (2 GW – 10%) and scattered other countries (2GW – 10%).  The United States only adds 0.5% of the world’s solar thermal capacity each year (0.1 GW).  Of the 28 million square meters of solar water heating collectors installed each year, only about 0.15 million are installed in the US.

Looked at another way, these are the rates of solar thermal installation in some interesting markets (in units of  square meters/1000 people):

• World average: 4.2
• EU average: 5.6
• China average: 17.3
• US average: 0.5

We can do better, and we need to.  We can create jobs, save energy, save money, and develop a world leadership in all of the relevant renewable energy technologies, or we can lose out to other countries.   With intelligent policies to incentivize adoption of economical energy saving measures, and to help finance the up-front costs, we can play a part in the 60% worldwide growth in solar thermal last year.  Or we can sit on the sidelines.  You know what our vote is.

Siemens Acquires Solel

This week, Siemens purchased solar thermal giant Solel Solar Systems for $418 million. This purchase of Israel-based Solel Solar Systems will give Siemens as stronger market position in the increasingly hot solar-thermal space. Solel Solar Systems already has over 500 employees and is one of the world´s two leading suppliers of solar receivers, which are key components of so-called parabolic trough power plants. They are one of the world’s two leading suppliers of solar receivers and has been present on the Spanish market since 2006, and is also active in the US market. It produces solar troughs and is involved in the manufacture and installation of solar fields for large scale solar energy production.

We are excited to see such large activity in the solar thermal world, and the benefits for entrepreneurs, investors and the environment can be summed up by a quote this week from a Siemens executive:

“The market for solar thermal energy is highly promising, and vigorous growth is expected…” – René Umlauft

Cool Energy SolarHeart Engine News

Over the last 6 weeks or so we have been testing the latest version of the SolarHeart Engine (Gen 3). It started the first time we put heat to it, and has reached a max output of 1100 Watts of electrical power to date. We are refining the piston/cylinder liner design, and hope to get to our target of 1500 Watts soon!

A first look at the Obama cap and trade program on Grist

An acquaintance of mine, Chaz Teplin of NREL, started a thread on Grist that I found interesting enough to comment on.  A price on carbon is coming, and the external costs of polluting that get tacked onto fossil fuel use will determine if we are serious about avoiding global warming and ocean acidification, or not.

Atlantic Graphics – The World is Spiky

Some very interesting visualizations of population distributions, wealth-generation distributions, and intellectual property development distributions were published by the Atlantic Monthly.  As much as I like what Thomas Freidman stand for these days around renewable energy and support for innovative companies, I never could quite relate to the flat world theory.  This brief article is more in line with my views.

Plots and Charts of Historical Financial Market Data

Some perspective on where we are today in financial history, with great charts, is here.  With the market behavior lately, it’s good to get some perspective.

Concentrating Solar Power Research

A new Department of Energy program has awarded 15 new grants for concentrating solar power storage technologies.  It is great to see the re-birth of R&D in American renewable energy!

Cool Energy in Boulder County Business Report

There was an excellent article on Cool Energy in the Boulder County Business report last Friday, February 6, 2009.  Many thanks to the reporter for getting the story accurate and readable!