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Passive Solar

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AGelbert:
https://www.youtube.com/watch?v=30ghnDOFbNQ&feature=player_embedded
Couple Builds Greenhouse Around Home to Grow Food and Keep Warm 

http://ecowatch.com/2015/11/30/greenhouse-around-home/

AGelbert:
This glass sphere might revolutionize solar power on Earth
Great article and excellent video!

http://themindunleashed.org/2013/12/glass-sphere-might-revolutionize-solar-power-earth.html

AGelbert:
Cooking with Sunshine    - Saving More Than Energy
Did you now that a solar oven can cost as little as $5 and last two years?

SCI stands for Solar Cookers International, a Sacramento, CA non- profit organization that with the help of other aid groups have trained more than 30,000 people in developing countries to cook with the sun. They are spotlighted in this National Geographic clip.

This amazing invention is a perfect solution to so many problems that transcend simply saving energy.

In developing countries, women have to walk 2- 3 miles to get firewood to cook with. Having this constant indoor pollution burns their eyes and chokes their lungs. The solar oven puts an end to these problems as well as deforestation.

Another truly life saving aspect of the solar oven: It can be used as a sustainable way to purify water. If you heat water to 65 degrees Celsius (149 degrees Fahrenheit) you can pasteurize it and make it safe to drink. See in the video how they created a simple way to measure if the water has reached this temperature.

One happy recipient says : "We are all amazed that a cardboard box can cook!" 


 --Bibi Farber
https://youtu.be/Ofn7jqPDTeY

https://mail.google.com/mail/u/0/#inbox/1572df6368c3636a

AGelbert:
Aluminum Can Solar Heater by Lillyvilleky in energy

--- Quote ---This is how I made an aluminum can solar heater!
--- End quote ---

http://www.instructables.com/id/Aluminum-Can-Solar-Heater/?ALLSTEPS

AGelbert:
The most efficient way to heat water is with a vacuum tube
Agelbert NOTE: The most thermodynamically efficient way to heat water is with a vacuum tube. WHY? Because a vacuum has no thermal conductivity. You trap the heat and that heat tranfers to the matter inside it as long as the sun is out. The tube cracking hazard with these tubes is demonstrated in this video and the surprising (i.e. using SAND!  :o   ) solution  is explained. 

By the way, vacuum tube solar water heating for homes is routine in China where they use solar panel  harvested electricity more for other energy needs. Solar panel electricity is obviously better used for other household electrical demands.

If we did not use electricty to heat our water in the USA, an estimeted 30% LESS energy would be required on the grid! That is a gob smacking amount of energy we unnecessarily waste each year!

Much of China is as far north as Canada, so please do not bring up the "cold climate" excuse for not using this method. No matter how cold it is outside, that cold cannot get to the solar heated part of the vacuum tube because there is ZERO thermal conductivity.

While it is true that air has low thermal conductivity, in northern climates the air in the air tube type is being cooled constantly, which counteracts the solar heat and causes excessive cooling of the water at night. Consequently, air tubes for heating water (note: they do work okay for heating house air) are a bad idea for anything but tropical climates.

Metals are excellent thermal conductors, but they have the electrolysis problem of corroding when dissimilar metals are in contact, so a non-metal type material inside the vacuum tube is preferable to a metal that contacts the copper water pipe within.

Thermal Conductivity Chart
The sand used in the video is VERY fine grained. The finer the grain, the more heat you will be able to capture in it. Coarse grained sand is useless.

Beyond aesthetic considerations, there is no valid reason whatsoever for us to use electricity to heat our water in the USA. Lazy human love of convenience and fossil fuel piggery are selfish, but not scientifically valid, reasons. Have a nice day.   

https://youtu.be/G4NNrRLPsnI
Evacuated Solar Tube Implosion Solar Water Heater Thermal Storage 
GREENPOWERSCIENCE   
 
Published on Jun 5, 2016

Solar evacuated tubes are extremely efficient at transferring sunlight to heat. This heat is then transferred to the material inside. This video is for lower quality water heaters that may experience rain water infiltration from poor designs. This is also an efficient method for enhancing good designs enabling solar thermal storage. If you use heated water in the morning from a system like this, the standard fins may be a better option. The thermal storage does last several hours.

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