Reply To: EmDrive + Focus Fusion = Space Access for all?

[HermannH]

Tulse wrote:

Also, if you have low overall gain the waste heat that is generated is going to be very large compared to the net electrical output.

Of course, the “waste” heat itself can be used either to generate further electricity, or for heating and industrial applications, making the system more economical than figures for just direct electricity generation might suggest.

That is theoretically true, but the coolant temperature must be significantly lower than the maximum operating temperature of the part that needs to be cooled. Therefore the waste heat is probably at a relatively low temperature unlike in a coal power plant where the boiler temperature is pushed as high as possible. The higher the ‘steam’ temperature the more useful things you can do with it. It’s like a car, the waste heat from the engine is good for heating the car in the winter, but otherwise it is just a problem.

My expectation is that the steam temperature is going to be barely high enough to make it worthwhile to generate electricity from it. Also, keep in mind that having to attach a conventional steam based power plant to a FF reactor negates many of the cost advantages.

Imagine a reactor where you have only 10% gain over unity. That means if you feed 1 Mega Joule of energy from the capacitors into the device the electrical energy harvested is 1.1 Mega Joule. 1 Mega Joule of that is needed to charge the capacitors for the next shot, so you are left with a net output of 100 kilo Joules. But you also just generated close to 1 Mega Joule of heat that needs to be disposed. Your ratio of waste heat to useful electrical power is 10 to 1. If your gain is 5% over unity that ratio goes up to 20 to 1 and you will use up all the generated electricity just to power the cooling pumps.

So it is critically important that the gain is significantly higher than unity.