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Power

Submission + - New Slash Based Energy Forum (r2dot.org)

Submitted by
rohar
rohar writes: "Having lurked around SlashDot since the late '90's and watching the lack of scalability of some of the newer blogging software, I thought I would put together an energy based forum on some "Old School" Slash that brings together my main interests: Open Source IT and renewable energy system design. The intent is to provide a free hosting system for renewable and traditional energy bloggers that lowers the time commitment and has the features like group moderation and threaded comments that make comments and discussion a little more scalable than blogging. r2dot.org is up and running and after messing with Slash for a week, I have a love/hate relationship with CmdrTaco. :)"
Slashdot.org

Ask Rob Malda 405

Posted by Roblimo from the once-every-seven-years-is-enough dept.
We last interviewed CmdrTaco, along with Hemos, in January 2000. Slashdot's 10th anniversary seems like a good time to put Rob back on the hot seat. He's older now and married, his former hobby site now has well over one million registered user IDs, and Linux has gone from "upstart" operating system to a normal part of the IT landscape. So ask away, one question per post. Expect to see answers to at least 10 of the highest-moderated questions next week. And if you miss your chance to participate in this interview, don't worry. We'll probably do another one with CmdrTaco sometime between 2014 and 2017. CT: Also the clock is ticking if you want to sign up for a Slashdot 10-Year Anniversary party if you want a T-Shirt or a shot at the $1k ThinkGeek gift certificate.

Comment Re:Efficiency? (Score 4, Informative) 78

by rohar (#19126181) Attached to: SHPEGS — DIY Solar/Geothermal Electricity

For a solar tower you..
Convection tower performance is very poor and the convection tower portion of the SHPEGS system accounts for less than 10% of the system output. It is still clean renewable power, but the convection tower wind turbine output is trivial. The chimney is there to allow a large volume of air to move across the heat exchangers efficiently and the wind turbine takes a slight advantage of the effect, but it isn't significant.

I wonder how this would be for growing winter crops as well

The thermal storage would be deep enough to not interact with the surface or shallow groundwater. The Drake Landing project has some information. This is another research document on thermal storage.

There is a lot of potential for integrating bio-methane which requires a very constant temperature as well as this Solar Hydrogen from methane production system. Algae farming also has a potential integration with the solar thermal storage.

Thanks. I'm looking for a number though.

I don't mean to avoid the efficiency question. Again, in an arid location with the majority of electrical usage for AC, Solar PV or Solar Thermal is simpler and probably more suitable. The cost/m2 of collectors is substantially cheaper in a thermal system, so I'm not sure what you are comparing. Marginal and poor land that isn't suitable for crop production or the roof of a Walmart isn't the cost factor, the solar collector is. The MIT group was able to get 1kW from 14m2 of trough collectors on a straight thermal system and the SHPEGS additions should improve on that.

There are also 2 heat sources in the SHPEGS system, solar and hot summer air along with two power generation systems, thermal and the wind turbine. In theory, the absorption system should improve not degrade the straight solar thermal system, so I would expect something better than 10% efficiency on the solar portion if you include the additional heat from the air. The conversion efficiency of the heat being extracted from the air is difficult to calculate. The energy cost is the energy going into the solution pump to pressurize the aqueous ammonia and there isn't the same direct cost in the volume of air being moved, in fact the more air that is moved the better the output of the wind turbine portion.

I used 5% thermal to electrical efficiency for the calculations to be conservative, and generally 10% is used for binary geothermal plants.

If you are comparing Solar PV, you need to account for battery cost and cut all the numbers by at least 50% to account for the daytime only output. Regardless of what is used for electrical storage, there are 3 months of the winter in Canada and the northern US where Solar PV isn't going to put out anything substantial and seasonal electrical storage isn't feasible.

The Toronto Exhibition Palace Live Solar PV Stats page has some historical data on Solar PV in winter in Canada.
Power

Submission + - SHPEGS: DIY Solar/Geothermal Electricity

Submitted by
rohar
rohar writes: "SHPEGS is an open design not-for-profit project to design and prototype a base load renewable electrical generation system suitable for moderate climates and built from common materials. The design centers around creating a local geothermal source with an efficient solar thermal water heater system and can be scaled from the single residence to the mega-project. The project was recently featured in an in-depth The Future of Things article. The heliostat system used in Europe's First Solar Thermal Plant could be used in a scaled down SHPEGS system with Practical Solar's small scale heliostats."
Biotech

Submission + - RIP dust-to-dust.... hello dust-to-silk

Submitted by Paul Pareti
Paul Pareti writes: Seven years ago there was a weird sci-fi short story in the London Magazine. It imagined a project where hybridised silk moths could be genetically instructed to feed on human cadavers instead of mulberry leaf. So they produce an unusually deep colored silk. Now a team of Japanese scientists is reported in the Proceedings of NASUS to have genetically modified silk moths to produce a range of different colors, depending on diet. Not quite eating human flesh yet; but how long is it before cremation is replaced with digestion? And we get to spin our own burial shrouds....
Power

Submission + - Europe's First Solar Thermal Power Online

Submitted by
rohar
rohar writes: "According to BBC News, Solucar, a division of Abengoa has brought Europe's first commercial solar thermal power station online. It is generating 11MW using a heliostat flat mirror and central tower solar steam system. A video of the system is available from BBC.

The system design would integrate very well with the SHPEGS concepts and combining this type of CSP plant with seasonal thermal storage and a massive air-coupled solar heat pump has a very strong potential for high summer insolation/cold winter climates like Canada and the Northern US and Europe."
Power

Submission + - Heating Your Home With A Geothermal Pump

Submitted by Makarand
Makarand writes: This article in the Chronicle describes how geothermal pumps could be used to heat our homes instead of natural gas or electricity. These pumps rely on the fact that regardless of what the surface temperature of the earth is, it is always 60 degrees a few hundred feet below. You have to drill a few holes 200 feet deep and insert U-shaped tubes in them and connect these to a heat exchanger. The tubes are filled with a solution of water and alcohol to prevent corrosion. Circulation pumps drive the water solution through the tubes in the ground and when the solution comes up from underground it is warm because it has passed through an environment of about 60 degrees.The heated liquid then is passed through the heat exchanger which takes care of the business of heating your home.
Power

Submission + - The Future of Things: SHPEGS

Submitted by
rohar
rohar writes: "The Future of Things has an article/interview on the Open Source SHPEGS project. The SHPEGS project is a not-for-profit renewable system design project with the focus of creating a clean, baseload, renewable power system for moderate climates based on solar, geothermal and heat upgrader/pump steampunk technology. The SHPEGS design takes advantage of moderate climates by capturing the heat from the high summer solar insolation and warm summer air of more northern locations and storing it in massive thermal storage. During the winter cycle power is generated as with a traditional geothermal system and a massive quantity of ice is stored underground for summer efficiency. The initial SHPEGS system was featured on slashdot back in January and has seen many refinements in design, interest from commercial ventures and improvements in presentation materials as the project has moved along. Vinod Khosla is a major proponent of Solar Thermal power generation, and he speaks on it in these Australian Four Corners videos."
Power

Submission + - TFOT: Open Source Solar/Geothermal Project

Submitted by Anonymous Coward
An anonymous reader writes: TFOT has a detailed article on an open design renewable energy project. The article give a good overview of some existing renewable systems, their shortcomings and an interview with the SHPEGS project initiator.
Power

Submission + - What's a SHPEGS?

Submitted by
rohar
rohar writes: "In the few months since this Open Design Renewable Energy Project was initiated, the concept has seen vast technical input from many sources and the design and calculations have gone through several revisions. The project has recently had several serious inquiries from VC firms and commercial entities and is rapidly moving into the demonstration project phase. The project will remain open and not-for-profit and attempt to assist commercial entities and communities in adapting the system.

The design focus is to build a feasible renewable base load power station from common materials for moderate climates like Western Canada where there is high solar isolation during the summer, but very cold temperatures and little daylight in winter. A binary geothermal system is integrated with massive local underground thermal storage and a solar thermal powered air-coupled absorption heat pump water heater that has the potential to more than double the thermal output of the solar collectors. Power is generated while heating the thermal storage in the summer and this local thermal storage is used in a traditional binary geothermal system in the winter. The sub-0C winter temperatures and relatively close thermal storage allow for an efficient geothermal system in the winter and the winter air will cool the thermal storage well below freezing for efficient summer operation.

A SHPEGS is a Solar Heat Pump Electrical Generation System."
PlayStation (Games)

Submission + - Cluster Computer Built from PS3's

Submitted by jbcage
jbcage writes: A professor at North Carolina State University has built a cluster computer using 8 PlayStation 3's running Linux. "His cluster of eight PS3 machines — the first such academic cluster in the world — packs the power of a small supercomputer, but at a total cost of about $5,000, it costs less than some desktop computers that have only a fraction of the computing power."

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