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[citation needed] Some natural gas-driven home fuel cells can generate eight times more energy per year than the same-sized solar installation, even in the best solar locations [citation needed]. For example, a 5 kW home fuel cell produces about 80 MWh of annual combined electricity and heat, compared to approximately 10MWh generated by a 5 kW ...
The distribution network is more costly to build than for gas or electric heating, and so is only found in densely populated areas or compact communities. Not all central heating systems require purchased energy. A few buildings are served by local geothermal heat, using hot water or steam from a local well to provide building heat.
In a modern high-rise building with a well-sealed envelope, the stack effect can create significant pressure differences that must be given design consideration and may need to be addressed with mechanical ventilation. Stairwells, shafts, elevators, and the like, tend to contribute to the stack effect, while interior partitions, floors, and ...
One classical thermal escape mechanism is Jeans escape, [1] named after British astronomer Sir James Jeans, who first described this process of atmospheric loss. [2] In a quantity of gas, the average velocity of any one molecule is measured by the gas's temperature, but the velocities of individual molecules change as they collide with one another, gaining and losing kinetic energy.
The landmark rule from South Coast AQMD would phase out more than 1 million natural gas-powered appliances, including those that heat swimming pools and hot tubs, and require them to be replaced ...
In comparison to an automobile weighing 1500 kg or more, a bicycle typically requires 100–200 times less energy to produce than an automobile. In addition, bicycles require less space both to park and to operate and they damage road surfaces less, adding an infrastructural factor of efficiency.
The orbital phasing can be problematic; once rendezvous has been achieved, low delta-v return windows can be fairly far apart (more than a year, often many years), depending on the body. In general, bodies that are much further away or closer to the Sun than Earth, have more frequent windows for travel, but usually require larger delta-vs.
A Bussard ramjet, one of many possible methods that could serve to propel spacecraft. Interstellar travel is the hypothetical travel of spacecraft between star systems.Due to the vast distances between the Solar System and nearby stars, interstellar travel is not practicable with current propulsion technologies.