A Passively Cooled House in the Tropics

passive house tropics

Build-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

“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:

Light Your Organic Tobacco in a Sustainable Way

light your tobacco in a sustainable way

The 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.