kpmancus@phoenix.Princeton.EDU (Keith P. Mancus) (03/30/89)
I've been trying to figure out how to get a "heat-pump" effect to use the fusion system to pump up a heat exchanger to a reasonable temperature. That is, assume that our fusion source will remain at the boiling point of water regardless of what mass flow of coolant we pass through it. What coolant should we choose to allow a production of temperature of ~3000 K on the other end? To see this more clearly, see the following picture. |----------| -> ------ -> ----------- | ------------| 2 |-------------| | | ------------| |-------------| | | | ------ | | | 1 | | 3 | | | ------ | | | |--------------| |----------| | | |--------------| 4 |----------| | |----------| ------ ----------- 1> This is the fusion reactor. Presumably it uses liquid D2O at very high temperature. Ideally it should run at 650 C or so, and very high pressure. It vaporizes the working fluid. 2> This compressor compresses the working fluid (presumably a metal or mixture of metals -- NaK perhaps?) to much higher pressure. In doing so it also raises the temperature. 3> This is the combustion chamber. The working fluid, at high (preferably > 2000 C) temperature, goes through a heat exchanger which heats reaction mass (probably but not necessarily H2) and lets it flow through a standard rocket nozzle. 4> The working fluid is now liquid again. It flows through a nozzle at (4) which drops it back to low pressure. It then reenters (1) as a low pressure liquid again. This is basically a heat pump cycle, but at high temperatures. We certainly can't use water or Freon as the working fluid! I haven't worked out yet just how much of the energy producing the high temperature at (3) comes from the heat at (1) and how much comes from the electrical energy put in the compressor at (2). We assume that a second cycle operates between (1) and a low temperature radiator to produce the electrical energy (through a turbine generator). Still in the thinking stage.... -- ------------------------------------------------------------------ -Keith Mancus <kpmancus@phoenix.princeton.edu> <- preferred <kpmancus@pucc.BITNET>
prs@oliveb.OLIVETTI.COM (Philip Stephens) (03/30/89)
From article <7473@phoenix.Princeton.EDU>, by kpmancus@phoenix.Princeton.EDU (Keith P. Mancus): > > 1> This is the fusion reactor. Presumably it uses liquid D2O > at very high temperature. Ideally it should run at 650 C > or so, and very high pressure. It vaporizes the working fluid. Why boil the D2O? Better to pressurize it so it remains in contact (very high pressure at 650 C, so I'm not sure how hot you can practically run if following my suggestion), and use a non-Pd heat sink to transfer the heat energy to another working fluid. The rest I have no comment on; I'm really thinking more in terms of generating electricity, so anything over 200 C would do pretty well; for driving any working fluid out a rocket nozzle, much higher temperatures would certainly seem desirable. 'Take what you can use, leave the rest'. ---Phil (prs@oliven)