The Most Effective Solar Cell

Solar cell embodied energy“One can note that the carbon intensity of China at 788 g/kWh is greater than that of Canada at 184 g/kWh. (…). The most effective carbon-mitigating PV cell would be produced in Canada and sent to China. The low carbon intensity of the electric grid in Canada and corresponding low embodied carbon of the cell would combine with the high mitigation potential in China to produce an optimized mitigation technology.”

Unfortunately, it is the other way around. Solar cells are produced in China, and shipped to countries with relatively clean electric grids.

The quote is from: “Towards real energy economics: energy policy driven by life-cycle carbon emission“, Energy Policy 38, 2010.

Build a Solar Thermal Direct-Air Heater for $200

solar thermal direct air heater

“The town I live in is located near the Alberta-BC border, about 100 miles north of the US Canada border. Winters here are long and cold, but many days are crystal clear and sunny.”

“Our tool shed has a south-facing wall which was ideal to mount a solar thermal direct-air collector panel. The collector panel exterior dimensions are 48” high x 49.5” wide. Total budget: $200.00 Result: 16 sq ft harvest up to 6 kWh/day.”

Build a Solar-Thermal Direct-Air Heater (PDF). Introduction (and another project) here.

Bicycle Trailer with Solar Panel Charges Electric Bicycle

Bicycle Trailer with Solar Panel Charges Electric Bicycle

“The electric bicycle has become a very long way in recent years. However, the lack of luggage space and limited range of the battery makes the electric bike less suited to long distances. Solarwind, designed by architect Raf Van Hulle, offers a solution.

The trailer provides extra luggage space and is fitted with a solar panel to keep the electric bicycle’s battery charged.”

Solarwind.

Open Source Energy Production: The Solar Fire P90

solar fire p90

Solar Fire is currently testing a larger version of its low-tech solar concentrator; the Solar Fire P90. Just like its smaller predecessor the Solar Fire P32 (which we covered before), the machine can produce heat, electricity and direct mechanical energy, making it suitable to manufacture almost anything on your roof or in the garden.

The Solar Fire P90 delivers up to 5 kW of electricity and 40 kW of thermal energy, is built using simple, abundant and non-toxic materials, and requires no foundation in the ground. The frame size is 11.5 x 11.5 metres and the machine requires an area of 16 x 16 metres for revolving.

Tracking is done by hand using a simple but ingenious system — one person can operate up to five of these solar concentrators at the same time. The Solar Fire P90 is an open source design, but it can also be bought for about $ 12,000, excluding transport costs.

A video of the tests can be found here. For more information on the workings and applications of these kinds of machines, see the article “The bright future of solar thermal powered factories“.

Picture: Solar Fire.

Solar Cookers That Work At Night

solar cookers that work at night

The solar cooker only works for a few hours in the middle of a sunny day, but not at night or in the mornings when people actually want to cook. Working better means working at night. Climate Healers, an international development technology organization, issued a design challenge last year after their traditional solar cookers failed to catch on in mountain villages in Rajasthan, India.

The challenge was to design a low cost stored energy solar cook stove that could store solar energy without requiring manual interventions from the user. The energy should be stored for at least an 18 hour period and should then be delivered at the users’ control to cook their traditional meals at the times that they choose, which may not necessarily be when the sun is out. People should be able to cook indoors, sitting down. The stove top temperature should be about 200ºC, with heat delivered at approximately 1 KW to the cook surface.

Three US university teams accepted the challenge in early 2011. Later that year, dozens of Indian university teams entered their proposals into the Shaastra Social Innovation Challenge at the Indian Institute of Technology, Madras. Engineering For Change has published the finalists’ papers online. The ten designs follow different strategies, using materials such as sand, aluminum cans, rice husks, water, salt, straw, or olive oil to store solar heat.

Find all the papers at Engineering For Change. Via Makeshift.

Parabolic Basket and Tin Can Solar Cooker

parabolic basket and tin can solar cookers“The objective of this project is to create a solar cooker out of local invasive species and waste materials. We want to create a device that can pasteurize water and be an alternative to the use of fossil fuels for cooking food.”

“The structure of the parabolic solar cooker will be made from the canes, or stems, of the locally invasive Himalaya blackberry. Canes will be harvested and dethorned so they can be woven into a parabolic basket shape. The Himalaya blackberry canes form parabolic curves, so when they dry and stiffen they will maintain the sturdy parabolic shape of the basket.”

“To give the parabolic cooker its necessary reflective surface, we gathered around 300 tin can lids to line the inside of the basket. We punched holes in the can lids so we could string them together in lines of 8-10 lids each. Then we tied these lengths of can lids to the basket using either hemp twine or twist ties. Since there were still many spaces on the basket uncovered by can lids, we gathered a bunch of large can lids and attached those individually to the basket.”

Read more: Parabolic basket and tin can solar cooker. More DIY-posts. Previously: The bright future of solar powered factories.