Why Solar Roadways are a Silly Idea

“There’s currently a virtually endless supply of places you could install solar panels that DON’T have cars driving over them.” Read more at Equities and check out the comments at Slashdot.

Solar Powered Grain Mill

“Graining cereal crops is a basic, century old business and it will continue to be as important as ever before for centuries to come. Before the age of oil grain milling was entirely based on renewable energy. It was either done by wind energy, hydropower, animals or manpower. For the last century the traditional grain milling has been mainly replaced by electricity and fuel driven milling.”

solar milling

“The Solar PV Grain Mill works to the same principle like any conventional, electrically driven mill. The mill has a very efficient 3-phase AC motor which is directly coupled to the graining system. The main invention of the system is, and that makes it unique among PV systems, that it is a “direct drive system” without the need of batteries. The Solar PV generator converts solar radiation into electricity, and the generated electricity is directly feeding the motor drive. There are no additional conversion losses, such as energy storage losses in batteries, battery maintenance or replacement costs, which are a common problem in conventional Solar PV off-grid systems.”

Read More: Solar Milling. Via Engineering for Change.

I would like to add that the direct drive system also eliminates the high energy use caused by the production of the batteries, which can make solar PV off-grid systems everything but sustainable. Therefore, storing work instead of energy — the solar mill only operates when the sun shines — is a very interesting strategy in sunny regions.

Related:

The Passive Solar Bird Bath

The passive solar bird bath provides some unfrozen water in the winter for the birds to drink. Its a nice simple design that is easy to build. The sun shines through the glazed panel on the south side of the pedistal and warms a solar absorber which heats the bird bath from below during the day. Jim got the idea from passive solar horse watering troughs. Find the building plans at BuildItSolar.

A Passively Cooled House in the Tropics

passive house tropicsBuild-It-Solar blog writes:

Kotaro Nishiki built a passively cooled home in Leyte Philippines at 11 degs north latitude that incorporates a number of unique cooling features that allow the home to be cooled passively and without electricity…

In this area, most homes are constructed of concrete, and the concrete structures tend to absorb solar heat during the daytime, and then retain that heat through the night making the homes uncomfortable.

Kotaro’s design is centered on eliminating these daytime solar gains. He keeps the whole house shaded using these techniques:

  • The south facing single slope roof has on overhang on the south that keeps the south wall in shade most of the day.
  • The north side of the house is shaded by an roof extension sloped down to the north that shades the north side of the house most of the day.
  • The roof is double layered with airflow between the well spaced layers.  This greatly reduces solar heat gain through the roof.
  • The east and west walls of the house are double wall construction with a couple feet between the walls.  The shading that the outer wall offers plus airflow between the double walls keep the wall temperatures low.
  • In addition, he has worked out ways to take advantage of the night
    temperature drop and to use thermal mass on the basement to provide some
    cooling.

More: A unique, passively cooled home in the Tropics (Build-It-Solar), Passive Solar House in Tropical Areas (Kotaro Nishiki). Build-It-Solar has more examples of passively cooled houses.

High-tech Solar Cooker

“Instead of a big solar oven that adapts to our conventional idea of cooking, The GoSun requires a bit of adaptation of our diet. But that really is a feature, not a bug; it can be a healthier diet with less food waste.” Read more: GoSun stove reinvents solar cooking.

Ask No Tech Magazine: Self-Replicating Solar Kilns?

Jon Freise sends us the following question.

helioforge“Have you come across any designs for solar ceramic kilns that might be able to manufacture glass mirrors? If a solar kiln was powered by mirrors, and if it could make a mirror, then it would be possible to have a self replicating solar economy. If the supporting frame was wood instead of steel, it would be possible to assemble anywhere. My college had several wood parabolic dishes used to transmit sounds over long distance. They were built as a toy.”

“I am not certain this concept is even possible. I don’t yet know enough about glass making. But if it was possible to get a net energy gain using a mirror kiln, then solar powered ceramic kilns, solar ovens, and solar brick works, and possibly solar cement works could spread across the world in a self replicating fashion. Your Nubian Vault article shows just what could be done if solar brick works and cement kilns were possible.”
Jon: the Helioforge project is an open source effort to create accessible designs for self-replicating solar kilns and hydrogen crackers that utilize readily available resources. Similar technology was also featured in the article on solar powered factories.

If anyone has more information, comments are open.

Solar Wood Drying Kiln

“Lumber is usually dried to a specific moisture content prior to further manufacturing or use. While lumber can be air-dried, the humidity in most localities prevents the lumber from reaching the moisture content required for the stability needed for interior use. The kiln discussed is designed to be inexpensive to construct and be simple to operate.”

solar wood drying kiln“The solar kiln described was designed, constructed, and tested at Virginia Tech. This design is based on 25 years of research and development on the solar drying of lumber in the United States and foreign countries. Drawings for two versions of this kiln are available; one for 800-1,000 bd ft and the other for 1,500-2,000 board feet of lumber. Both kilns will dry a load of lumber in approximately one month of moderately sunny weather at its location in Blacksburg, VA.”

“Drying lumber can be a complex process where accelerating drying without having quality loss often requires extensive knowledge and experience. The design of the Virginia Tech solar kiln is such that extensive knowledge, experience and control are not required. The size of the collector keeps the kiln from over-heating and causing checking and splitting of the wood. The kiln is simple to construct and utilizes a passive solar collector, four insulated walls and an insulated floor. The roof is made of clear, greenhouse rated, corrugated polyethylene.”

Virginia Tech Solar Kiln. Via Build It Solar.

Earthen Solar Cooker

Earthen_Solar_Cooker_2012“The Earthern Solar Cooker is a large parabolicly shaped hole in the ground lined with reflective materials such as salvaged pieces of broken mirrors or reflective can lids. The mirrors reflect and concentrate sunlight to the base of the hole where ten one gallon black containers of water can be boiled per hour and used for drinking or food preparation. Cooking/water boiling containers are accessed via steps carved into the side of the Earthen Solar Cooker.”

“A 2.5m diameter hole, 1.5m deep cooks 10 gal of rice/hr from 11am to 3pm on an 85f summer day in south central Oregon. Since the power of a parabolic concentrator is proportional to the surface area of it’s aperature (A = 3.14 x r^2), doubling the radius of the hole increases the power of the Earthen Solar Cooker by a factor of four. An Earthen Solar Concentrator the size of a small amphitheater might be capable of casting bronze or boiling the water near the surface of a shallow well located at the vertex, thus making possible the creation of a solar bubble pump that could lift pasteurized water to a tank above ground level.” Read more about the project at Appropedia.

Previously: Parabolic Basket and Tin Can Solar Cooker / Solar Cookers that Work at Night / Build a Solar Powered (Interior) Kitchen.

Light Your Organic Tobacco in a Sustainable Way

Solar fire starterThe Solar Spark Lighter is a pocket-size solar firestarter and lighter. It is a stainless steel parabolic mirror, like the one used to light the Olympic torch. It is designed to focus the sun’s radiant energy to a precise focal point that can reach hundreds of degrees. Just point it at the sun and it lights in seconds. Measures about 4.5″ diameter.

An Engineering Exploration of Stonehenge

Stonehenge and heavenshingeThe Britons worked out how the heavens move thousands of years before the Greeks started thinking about it. That is, in a nutshell, the story of engineer and author  Jonathan Morris.

His hypothesis originated from a solar renewable energy concentration system which he developed, using small fixed pieces of flat reflectors.

By chance, he discovered that the structural support of the solar energy system appears to be duplicated at Stonehenge, the enigmatic monument built 4,000 to 5,000 years ago. Every single one of the technical features required are precisely duplicated in size, height, location and orientation at Stonehenge.

Morris outlines his ideas in a novel (“The Broken Stone”) and a technical outline, available via his website: “Heavens’ Henge: A geocentric worldview“.