Thought this was cool. A bit expensive though. Energy Balls currently are sold in sizes of either 1 meter or 2 meters in diameter. They can be installed on a pole or a flat roof in as few as four hours, Aurik said. In places where the wind is relatively strong — blowing 15 mph, or 7 meters per second, on average — a 1-meter ball can generate up to 500 kilowatt-hours per year, while the 2-meter ball can supply 1,750 kilowatt-hours per year. The typical U.S. household uses 11,000 kilowatt-hours per year, so additional electricity will have to come from somewhere. However, these are optimum values that assume the small turbine is mounted at least 40 feet (12 meters) above the ground and is free from surrounding trees and buildings that block the wind. The cost of the Energy Ball is between $3,500 and $7,000, not including installation.
I like that idea, esp. the fact that it's asthetically appealing and quieter than a normal turbine. Maybe 3 years from now, when we build our LEEDS home, they will be a little cheaper. With 2 or 3 of those instead of a traditional turbine we could get significant power, paired with PVs and geothermal we should be feeding the grid more than we're taking from it.
Cute idea, and has some merit. Don't be overly impressed by the efficiency claims. Their claims of increased efficiency are when comparing the ball to a similarly sized conventional turbine (small). Propeller efficiency drops dramatically when the blade size gets small. A large propeller turbine will be more efficient than the balls. The venturi effect cited in the article applies to all lifting surfaces, including normal propellers. I assume what they are driving at is low speed, high angle of attack operation. Normal propellers stall in this region of operation, but some lifting surfaces do well operating in the transition zone between laminar flow and full separation. Bumblebee wings are a classic example. Quieter operation is a plus. These balls trade blade speed for low end torque. As I said before, it's not as efficient, but it should be quieter in normal operation. Tom
Evan, make sure you do a wind profile study before you invest in wind (unless you KNOW the site has good wind resources). Gusty winds are not what you want. You want steady wind... and lots of it. If you don't know what sort of wind you've got, defo measure it for a year or so to evaluate the quality of the wind resource. A quick look at a MO wind resources map indicates that wind resources are generally sh*te in MO. However, you won't know at any given location until you measure it. Move to ND, then build your LEED house.
www.superturbine.net With a WindyGirl rectifier for selling to the grid. Multiple blades adds torque, more power than single blade.
Not to put too much cold water on this but,,, Beware claims in the RE biz, especially with regards to small scale wind. Having been in the RE/PV biz for a couple of decades, the absolute LAST renewable device to install is home/small scale wind. The hardware has been (generally) proven unreliable, the amount of wind over estimated and most people are disillusioned after a few years. Wind devices are mechanical devices that live and work in harsh environments, and are subject to large maintenece time/cost. Vertical axis turbines have the potential to have better reliability due to fewer/simpler moving parts, but they suffer from inifficiencies that are inherent to their design. I urge anyone who has a passing interest in installing small scale wind to visit the following site to get some real world insight from those that have gone before: Wind Power Generation - Solar Electric Discussion Forum I am a strong advocate for larger scale wind however. Many of the short comings of small scale wind are addressed due to scale. The height of the turbines are by design much higher than small scale can use (~150' vs ~30') getting the blades in stable air. The moving parts are larger, and the wear items (bearings etc) can be serviced from inside the turbine as opposed to having to lower a (heavy) device to the ground as required in small scale. The blades also turn slower, resulting in less wear on the bearings etc. In most climates, it is suggested that conservation should come first, second and third, followed by passive solar heat, solar hot water, active solar heat, PV solar, and at a great distance behind comes small scale wind. Icarus PS I know of no small scale vertical axis systems that are commercially available. I've seen lots of vaporware, but no real installations
Practically speaking, how are "passive" and "active" solar heat implemented? What is an example of what it is / how it's done?
In simple terms, a passive system requires no parasitic energy, while an active system may use pumps/fans and other energy consuming devices to move energy. An example of a passive solar system could be as simple as opening sun facing (not just south facing) window shades to take advantage of solar gain. You can also design in things like sunspaces with thermal mass designed into the structure to absorb heat passively during the day, giving it back at night for example. A "batch type" solar water heater would be an example of passive. A simple tank, inline with the water line to the water heater, encased under glass, absorbing heat until the call for water. Active systems are by nature more complicated and use some parasitic energy. A active heat system might pass air into and then out of a storage medium such as thermal mass like rock or water using a fan and thermostat system. Active water might be a flat plate collector that passes water through the collector and into a pre-heat tank using a pump and an aqua-stat. In point of fact, many systems are sort of hybrids of both. I live in a house with a solar greenhouse on the south side of the house. The sun shines in on a 3' thick insulated concrete slab all day. At the back of the roof I have used some old fashioned cast iron radiators filled with water to add to the mass. The sun shines on these all day. (The purpose of as much mass as possible is that it allows the mass to absorb BTU's without overheating the space, keeping the hot and cold temp swings to a minimum). At night I close the window quilts and the mass gives those BTU's back to the house. The system is totally passive,,,until I add a fan to move more air from the sunspace into the house. Most passive systems come at no real cost if they are thought about in the design stage. South facing glass, thermal mass, costs no more than anything else, but pays big dividends. We shorten our heating season on both ends but a month or two, and reduce the load the rest of the year, all using space the same way we would otherwise. Icarus
