PV Gap

Dale Said:

Geothermal Energy system?

We Answered:

You won't be generating electricity from a heat pump. You can get hot water for showers and washing from some units, but not electricity.

The heat pumps are sized by "BTU's" in the US as well as the size of the ground loop field. A competent installer should be able to tell you how they sized the unit for your home. It is not uncommon for different installers to use different criteria for sizing a system for your home.

Roberta Said:

psychical science help (only 8 questions)?

We Answered:

The answers are: A, C, B, B, E, D, A

Ray Said:

what are renewable sources??!?

We Answered:

First, hydropower is technically sustainable, but is no longer actually considered sustainable due to its huge negative impact on the environments. Our dams are aging, and will likely not be replaced in most cases.

Nuclear energy is basically the same form as fossil fuel, but using radioactivity as a source of heat rather than combustion of hydrocarbons. Fuel rods containing enriched U-235 spontaneously decay (alpha-decay, or emitting a helium-nucleus at high-velocity) into a huge tank of water. With thousands or millions of these decays taking place, the water heats up It then forces itself as it expands into an area where its own steam will turn a turbine (just like coal and oil). In more modern plants, the water is kept supercritical, meaning liquid, even though its temperature is above boiling point. This fluid itself will then turn the blades of the turbine, which is far more efficient. This often goes through a number of smaller and smaller turbines as the water cools, ending in a steam turbine before being returned to the heating pool and starting all over again. So a nuclear plant is just a really fancy steam turbine.

Geothermal energy receives hot, high-pressure fluids from beneath the surface. In the old-style plants, steam was once again used to spin the turbine. Modern plants either use the fluids themselves, or a heat transfer system to use the heat, but not the actual fluid, to spin the turbines, before it returns to the deep reservoir.

Solar power comes in two types. Solar photovoltaics ("solar cells"), and reflection.

With photovoltaics, the sunlight hits the silicon grid, and knocks an electron off of the wafer. This electron whips through a circuit, and since a moving electron creates electricity, you get... electricity. The electron will return to its original spot due to some interesting quantum physics. When you have this going on over millions of atoms and electrons, you can get a lot of electricity.

Reflection is when many mirrors are set up around a tall generator turbine. In these cases, they do not use water, they use sodium metal. The mirrors focus the sunlight on the tower, which liquefies the metal, and generates electricity. The use of a sodium metal (recently they're moving into other types of high-temperature fluids) allows for a significant energy density that water could never hope to achieve.

One old method of using solar power was to set up parabolic dishes... long, long dishes, and putting a pipe full of water at the focal point of the mirrors. The water would be heated, and... you guessed it, driven through a turbine, pretty much like every other steam turbine.

Wind power uses very large towers to capture the wind. There are many different types right now, with different shapes of capture-blades, different numbers, some even rotate vertically rather than horizontally. However, whatever method is used to capture the wind, these blades will cause that portion of the tower to spin, which in turn spins another electric turbine.

Deep-current and tidal power are again the same, using the physical motion of water to spin turbine blades.

Wave power is the very interesting one, one of my favorites (after wind and geothermal). However, the actual working of a wave buoy is rather complex. Sometimes, it's more of a long, enclosed, flexible pipe that uses an enclosed oil as a moving fluid to create electricity. Honestly though, there are many proven wave mechanisms, but I can't really help you out more. The number of systems, coupled with some physics that are beyond my own normal knowledge, will keep me from trying to explain it to you. If you want to know more, though, please by all means look into them, because it's fascinating.

I hope this helps!