Human power is the rate of work or energy that is produced from the human body. It can also refer to the power (rate of work per time) of a human. Power comes primarily from muscles, but body heat is also used to do work like warming shelters, food, or other humans.
World records of power performance by humans are of interest to work planners and work-process engineers. The average level of human power that can be maintained over a certain duration of time is interesting to engineers designing work operations in industry.
Human-powered transport includes bicycles, rowing, skiing and many other forms of mobility.
Human-powered equipment is occasionally used to generate, and sometimes to store, electrical energy for use where no other source of power is available. These include the Gibson girl survival radio, wind-up or (clockwork) radio and pedal radio.
Normal human metabolism produces heat at a basal metabolic rate of around 80 watts. [1]
During a bicycle race, an elite cyclist can produce around 440 watts of mechanical power over an hour and track cyclists in short bursts over 2500 watts; modern racing bicycles have greater than 95% mechanical efficiency. An adult of good fitness is more likely to average between 50 and 150 watts for an hour of vigorous exercise.[ clarification needed ] Over an 8-hour work shift, an average, healthy, well-fed and motivated manual laborer may sustain an output of around 75 watts of power. [2] However, the potential yield of human electric power is decreased by the inefficiency of any generator device, since all real generators incur losses during the energy conversion process. [3] [4]
It is possible to use exercise equipment for power generation, by attaching the moving parts to components of electric generators; [5] some home gym equipment uses DC generators to power readouts, displays, and control the amount of resistance offered by the machine. [5] The amount of energy generated is so small compared to industrial power sources that the cost of conversion equipment makes it financially impractical. [5] For example, supplying an average United States home solely with electricity generated from exercise equipment for one day would require more than a hundred people to ride stationary bicycles for all of it. [5] [6]
Several forms of transport utilize human power. They include the bicycle, wheelchair, walking, skateboard, wheelbarrow, rowing, skis, and rickshaw. Some forms may utilize more than one person. The historical galley was propelled by freemen or citizens in ancient times, and by slaves captured by pirates in more recent times. The MacCready Gossamer Condor was the first human-powered aircraft capable of controlled and sustained flight, making its first flight in 1977. In 2007, Jason Lewis of Expedition 360 became the first person to circumnavigate the globe at non-polar latitudes using only human power—walking, biking, and rollerblading across the landmasses; and swimming, kayaking, rowing, and using a 26-foot-long pedal-powered boat to cross the oceans. [7] [8]
Treadwheels, also called treadmills, are engines or machines powered by humans. These may resemble a water wheel in appearance, and can be worked either by a human treading paddles set into its circumference (treadmill), or by a human standing inside it (treadwheel).
Some devices use human power. They may directly use mechanical power from muscles, or a generator may convert energy generated by the body into electrical power.
Human-powered equipment primarily consists of electrical appliances which can be powered by electricity generated by human muscle power as an alternative to conventional sources of electricity such as disposable primary batteries and the electrical grid. Such devices contain electric generators or an induction system to recharge their batteries. Separate crank-operated generators are now available to recharge battery-powered portable electronic devices such as mobile phones. Others, such as mechanically powered flashlights, have the generator integrated within the device. Wrist watches can use muscle power to keep their mainsprings wound up.
An alternative to rechargeable batteries for electricity storage is supercapacitors, now being used in some devices such as the mechanically powered flashlight shown here. Devices that store the energy mechanically, rather than electrically, include clockwork radios with a mainspring, which is wound up by a crank and turns a generator to power the radio.
An early example of regular use of human-powered electrical equipment is in early telephone systems; current to ring the remote bell was provided by a subscriber cranking a handle on the telephone, which turned a small magneto generator. Human-powered devices are useful as emergency equipment, when natural disaster, war, or civil disturbance make regular power supplies unavailable. They have also been seen as economical for use in poor countries, where batteries may be expensive and mains electricity unreliable or unavailable. They are also an environmentally preferable alternative to the use of disposable batteries, which are a wasteful source of energy and may introduce heavy metals into the environment. Communication is a common application for the relatively small amount of electric power that can be generated by a human turning a generator.
The World War II-era Gibson girl survival radio used a hand-cranked generator to provide power; this avoided the unreliable performance of dry-cell batteries that might be stored for months before they were needed, although it had the drawback that the survivor had to be fit enough to turn the crank. Survival radios were invented and deployed by both sides during the war. [9] The SCR-578 (and the similar post-war AN/CRT-3) survival radio transmitters carried by aircraft on over-water operations were given the nickname "Gibson Girl" because of their "hourglass" shape, which allowed them to be held stationary between the legs while the generator handle was turned.
During World War II, U.S. troops sometimes employed hand crank generators, GN-35 and GN-45, to power Signal Corps Radio transmitter/receivers. [10] The hand cranking was laborious, but generated sufficient current for smaller radio sets, such as the SCR-131, SCR-161, SCR-171, SCR-284, and SCR-694. [11]
A windup radio or clockwork radio is a radio that is powered by human muscle power rather than batteries or the electrical grid. In the most common arrangement, an internal electric generator is run by a mainspring, which is wound by a hand crank on the case. Turning the crank winds the spring and a full winding will allow several hours of operation. Alternatively, the generator can charge an internal battery.
Radios powered by handcranked generators are not new, but their market was previously seen as limited to emergency or military organizations. The modern clockwork radio was designed and patented in 1991 by British inventor Trevor Baylis as a response to the HIV/AIDS crisis. He envisioned it as a radio for use by poor people in developing countries, especially in Africa, without access to batteries. In 1994, British accountant Chris Staines and his South African partner, Rory Stear, secured the worldwide license to the invention and cofounded Baygen Power Industries (now Freeplay Energy Ltd), which produced the first commercial model. The key to its design, which is no longer in use, was the use of a constant-velocity spring to store the potential energy. After Baylis lost control of his invention when Baygen became Freeplay, the Freeplay Energy units switched to disposable batteries charged by cheaper hand-crank generators.
Like other self-powered equipment, windup radios were intended for camping, emergencies and for areas where there is no electrical grid and replacement batteries are hard to obtain, such as in developing countries or remote settlements. They are also useful where a radio is not used on a regular basis and batteries would deteriorate, such as at a vacation house or cabin.
Windup radios designed for emergency use often include flashlights, blinking emergency lights, and emergency sirens. They also may include multiple alternate power sources, such as disposable or rechargeable batteries, cigarette lighter receptacles, and solar cells.
The pedal radio (or pedal wireless) was a radio transmitter-receiver powered by a pedal-driven generator. It was developed by South Australian engineer and inventor Alfred Traeger in 1929 as a way of providing radio communications to remote homesteads and cattle stations in the Australian outback. [12] There were no mains or generator power available at the time and batteries to provide the power required would have been too expensive. It was a highly important invention, [13] as it was this technology that enabled the Royal Flying Doctor Service, and later the School of the Air, linking people living remotely to emergency services and education. [14]
In electricity generation, a generator is a device that converts motion-based power or fuel-based power into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. Generators provide nearly all the power for electrical grids.
Clockwork refers to the inner workings of either mechanical devices called clocks and watches or other mechanisms that work similarly, using a series of gears driven by a spring or weight.
A power inverter, inverter, or invertor is a power electronic device or circuitry that changes direct current (DC) to alternating current (AC). The resulting AC frequency obtained depends on the particular device employed. Inverters do the opposite of rectifiers which were originally large electromechanical devices converting AC to DC.
Bicycle lighting is illumination attached to bicycles whose purpose above all is, along with reflectors, to improve the visibility of the bicycle and its rider to other road users under circumstances of poor ambient illumination. A secondary purpose is to illuminate reflective materials such as cat's eyes and traffic signs. A third purpose may be to illuminate the roadway so that the rider can see the way ahead. Serving the latter purposes require much more luminous flux and thus more power.
Trevor Graham Baylis was an English inventor best known for the wind-up radio. The radio, instead of relying on batteries or external electrical source, is powered by the user winding a crank. This stores energy in a spring which then drives an electrical generator. Baylis invented it in response to the need to communicate information about AIDS to the "people of Africa". He ran a company in his name dedicated to helping inventors to develop and protect their ideas and to find a route to market.
Energy harvesting (EH) – also known as power harvesting,energy scavenging, or ambient power – is the process by which energy is derived from external sources, then stored for use by small, wireless autonomous devices, like those used in wearable electronics, condition monitoring, and wireless sensor networks.
An atomic battery, nuclear battery, radioisotope battery or radioisotope generator uses energy from the decay of a radioactive isotope to generate electricity. Like a nuclear reactor, it generates electricity from nuclear energy, but it differs by not using a chain reaction. Although commonly called a batteries, atomic batteries are technically not electrochemical and cannot be charged or recharged. Although they are very costly, they have extremely long lives and high energy density, so they are typically used as power sources for equipment that must operate unattended for long periods, such as spacecraft, pacemakers, underwater systems, and automated scientific stations in remote parts of the world.
An electronic component is any basic discrete electronic device or physical entity part of an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial products, available in a singular form and are not to be confused with electrical elements, which are conceptual abstractions representing idealized electronic components and elements. A datasheet for an electronic component is a technical document that provides detailed information about the component's specifications, characteristics, and performance. Discrete circuits are made of individual electronic components that only perform one function each as packaged, which are known as discrete components, although strictly the term discrete component refers to such a component with semiconductor material such as individual transistors.
A mechanically powered flashlight is a flashlight that is powered by electricity generated by the muscle power of the user, so it does not need replacement of batteries, or recharging from an electrical source. There are several types which use different operating mechanisms. They use different motions to generate the required power; such as squeezing a handle, winding a crank, or shaking the flashlight itself. These flashlights can also be distinguished by the technique used to store the energy: a spring, a flywheel, a battery or a capacitor.
Electric power is the rate of transfer of electrical energy within a circuit. Its SI unit is the watt, the general unit of power, defined as one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billions of watts are called kilowatts, megawatts and gigawatts respectively.
Micropower describes the use of very small electric generators and prime movers or devices to convert heat or motion to electricity, for use close to the generator. The generator is typically integrated with microelectronic devices and produces "several watts of power or less." These devices offer the promise of a power source for portable electronic devices which is lighter weight and has a longer operating time than batteries.
A batteryless radio is a radio receiver which does not require the use of a battery to provide it with electrical power.
An emergency radio is, broadly speaking, a radio receiver designed to remain functional in cases of power outage or isolation from contact with civilization. Such radios are often designed to run on minimal or renewable power sources, such as solar.
A dynamo is an electrical generator that creates direct current using a commutator. Dynamos were the first electrical generators capable of delivering power for industry, and the foundation upon which many other later electric-power conversion devices were based, including the electric motor, the alternating-current alternator, and the rotary converter.
Freeplay Energy Ltd, , is a manufacturer and distributor of portable electrical or electronic products such as radios and lights, generally powered by hand cranked generators that charge rechargeable batteries. The company is based in London, UK. The company focuses on creating and developing the international market for self-sufficient energy products, and states that such a focus will help promote education and access to important information throughout the developing world. The company has expanded its market to include outdoor leisure and emergency preparedness markets, seeing the clear demand for self-powered products in such off-grid environments.
Load management, also known as demand-side management (DSM), is the process of balancing the supply of electricity on the network with the electrical load by adjusting or controlling the load rather than the power station output. This can be achieved by direct intervention of the utility in real time, by the use of frequency sensitive relays triggering the circuit breakers, by time clocks, or by using special tariffs to influence consumer behavior. Load management allows utilities to reduce demand for electricity during peak usage times, which can, in turn, reduce costs by eliminating the need for peaking power plants. In addition, some peaking power plants can take more than an hour to bring on-line which makes load management even more critical should a plant go off-line unexpectedly for example. Load management can also help reduce harmful emissions, since peaking plants or backup generators are often dirtier and less efficient than base load power plants. New load-management technologies are constantly under development — both by private industry and public entities.
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell.
A wearable generator is an article of clothing that contains some form of electrical generation system built in. The concept encompasses a variety of generation systems intended to supply small amounts of power to keep portable electronics in a good state of charge through natural motions of the body.
There are numerous versions of vehicle propulsion systems. Many of those came into fruition due to need for cleaner vehicles. Each of them might have many abbreviations and some might be misleading. This article explains shortly what defines them.
Electric(al) devices are devices that functionally rely on electric energy to operate their core parts. They can be contrasted with traditional mechanical devices which depend on different power sources like fuels or human physical strength. Electronic devices are a specialized kind of electrical devices in which electric power is predominantly used for data processing rather than the generation of mechanical forces. To better differentiate between both classes, electric devices that emphasize physical work are also called electromechanical. Mechatronics accentuates the intersection of both fields.
The motion of one body relative to another body with which it is in contact is accompanied by a friction force.
a gym might have to wait decades to recover the money it spent converting its exercise machines to generate electricity
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: CS1 maint: unfit URL (link)The Traeger pedal represents a significant milestone in the history of communication in Australia.
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