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Chris Hunt
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Hey everyone just wanted to throw this out so you could see the newest and most efficient design for solar energy collecting. It reduces the impact of waste by using a small panel and collects consistently rain or shine. The design and efficiency blow my mind everytime I think about it and have great respect for the inventor and founder of Rawlemon. Here's the link! https://www.indiegogo.com/projects/rawlemon-solar-devices
 
Topher Belknap
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Location: Midcoast Maine (zone 5b)
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Chris Hunt wrote:...collects consistently rain or shine


When I read that, I think 'only collects as much as a rainy day, even when it is sunny.' Which I don't think is what they are wanting to convey. The energy that is reflected by the clouds above is unavailable at the ground.

While efficiency (in terms of kWh collected per square foot of intercepted sunlight) is interesting, solar is being pushed at the moment by kWh per dollar. The reason most people give for not installing solar is price, not lack of enough collection area. And as that is going away, more people are installing solar. Most people don't even ask about efficiency.

Thank You Kindly,
Topher
 
Markus Loeffler
Posts: 30
Location: Altadena, CA, USA
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It's a nice looking gadget but unfortunately it is not efficient at all. It uses a huge sphere of glass to concentrate light onto a small solar panel that will be moved around to track the sun. This is equal to a dual axis solar tracking mechanism. The amount of energy it can use equals the surface area that is exposed to the sun. Here is a map of the energy levels reaching earth by square meter: http://solar-trap.com/?p=179
For a sphere that is A = 4*Pi*r*r . Because the way the sun moves you can only use half of the sphere: 2*Pi*r*r. As an example: a ball of 40cm diameter will give you 0.5 m2 surface. The same glass sphere has a weight of 0.03 m3 * 2531 kg/m3 = 76kg ~ 167 lbs. Yes, very heavy. You will get a little more surface (0.66 m2) with just one 26' by 40' panel - but that would not be as sexy as the gadget.
It is by far more costly to produce and install a huge glass sphere than mount a small panel. But unfortunately like with the 'Solar Roadways' campaign people get tricked into these gadgets and believe in unrealistic dreams. They on purpose NEVER publish real energy numbers. This one will end up in a landfill after 5 years because then even your phone will use 4x the amount of energy for charging.
 
Bill Crim
pollinator
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Location: Issaquah, WA
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The efficiency of No/Low fuel energy sources isn't the most important aspect. It's usually the capital and maintenance costs that make these sorts of solutions viable or not. In the case of this solution, which I have no doubt will work, the quality of the optics required will be cost prohibitive. When talking materials, greater purity usually means greater energy inputs. If they use lower quality glass, eventually the sphere will warp.

In the case of this system, if the tracking arm ever breaks down, you are going to start a fire, as the focal energy sweeps across your roof.
 
Tony Turkish
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Markus Loeffler wrote:It's a nice looking gadget but unfortunately it is not efficient at all. It uses a huge sphere of glass to concentrate light onto a small solar panel that will be moved around to track the sun. This is equal to a dual axis solar tracking mechanism. The amount of energy it can use equals the surface area that is exposed to the sun. Here is a map of the energy levels reaching earth by square meter: http://solar-trap.com/?p=179
For a sphere that is A = 4*Pi*r*r . Because the way the sun moves you can only use half of the sphere: 2*Pi*r*r. As an example: a ball of 40cm diameter will give you 0.5 m2 surface. The same glass sphere has a weight of 0.03 m3 * 2531 kg/m3 = 76kg ~ 167 lbs. Yes, very heavy. You will get a little more surface (0.66 m2) with just one 26' by 40' panel - but that would not be as sexy as the gadget.
It is by far more costly to produce and install a huge glass sphere than mount a small panel. But unfortunately like with the 'Solar Roadways' campaign people get tricked into these gadgets and believe in unrealistic dreams. They on purpose NEVER publish real energy numbers. This one will end up in a landfill after 5 years because then even your phone will use 4x the amount of energy for charging.


Just to let you know I'm not affiliated with Rawlemon by any means. I just searched this forum to see if anyone has this setup/any experience with it, because I'm interested in this product for a log cabin. Please use constructive critique based on hands on experience with the device, instead of tearing something down.

I'm not sure your calculations stand the test, just not my area of expertise. However, based on the manufacturer's specs this system generates twice yield compared with conventional panel, while utilizing only 1% of the conventional panel surface. Not sure what you mean by "not publishing real energy numbers." -- they are listed on their website in the open.

http://www.rawlemon.com/products/beta-ray-1-80
Technical data:
• Lens Design: Acrylic-Polymer ball lens, water filled
• Numerical Aperture: 1.8m diameter
• Electrical Data: 560W (220W/M2)
• Thermal Data: 890W (350W/m2)
• Combined Efficiency: 57% (Hybrid)
• Capacity Per Day: 3.4 kWH max.
• Battery Capacity: 0.5 kWh
• AC/DC Management: 120V / 220V - Client specific option
• Connections: Collector Header/Return Lines, 200V/16A Din-Socket
• Dual Axis Tracking: Low Inertia DC microdrive
• Control Unit: Tracking/ Sun/Moon, positioning LED beam
• Light Energy: 300lm - up to 800m Spot with LED's
• Weight: 3.350Kg (water: 3.055 liters)
• Dimensions: 3.90 x 2.40 x 3.15 meter
• Wind resistance: Up to 120 m/s

So judging by the specs, does anyone else have a hands on opinion of this thing? One good suggestion so far definitely is the failure of the tracking system -- don't want to start a fire.
 
Connor Macreno
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There was a discussion a while back, I think here on permies, about using water filled tubes as solar concentrators. This would seem to be the same idea using a ball instead of a tube.

Tubes seem to me like they could be a better option. You could use a linear concentrator with a row of tubes; very little energy used for tracking.

Put the whole thing in a box and draft air up through it for heat collection; maybe use it to preheat water passing through the tubes before running to a more standard solar water heater.

Some obvious issues in cold climates.
CLFR_Alternating_Inclination.JPG
[Thumbnail for CLFR_Alternating_Inclination.JPG]
 
Markus Loeffler
Posts: 30
Location: Altadena, CA, USA
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This device is not available so good luck finding anyone with "hands-on" experience. But I can break down numbers for you if you want to evaluate the 'beta-ray-1-80':

1)Numerical Aperture: 1.8m diameter

well, this is strange; the numerical aperture (NA) of an optical system is a dimensionless number (that means no meters) that characterizes the range of angles over which the system can accept or emit light. Is this the area that can catch sunlight?

2)Electrical Data: 560W (220W/M2)

looks like 220W per square meter -> 560/220 = 2.5 square meter

3)Thermal Data: 890W (350W/m2)

this is weird, there is no mentioning how you would use the hot water and the image shows absolutely no connectors. Also a clear water container is the worst solution in creating hot water.

4)Capacity Per Day: 3.4 kWH max.
This is the important number and you can use this calculator http://pvwatts.nrel.gov/ and type in your location and energy needs to compare it with regular solar-panels. I ran the numbers that get close to the 'beta-ray-1-80' with a fixed roof-mount solar array that gives you 4 kWh (15% more than the beta-ray):

DC Rating 1 kW
DC to AC Derate Factor 0.77
Array Type Fixed (roof mount)
Array Tilt 34.2°
Array Azimuth 180°

1kW you get with 4x 255W solar panels like these ones: http://www.altestore.com/store/Solar-Panels/SolarWorld-255-Watt-Solar-Panel-Sunmodule-SW255-Black-Mono-V25-Frame/p10573/

the cost are $1060 for the panels. You would need to add an inverter (about $200), a charge controller ($400) and battery ($400) and some cables. Lets round it up to $2500 for the entire system -- not counting labor & shipping.

Now the rawlemon lists with 9000 Euros, that is about $12000! Very little bang for the buck.
 
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